Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * linux/kernel/printk.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | * | |
6 | * Modified to make sys_syslog() more flexible: added commands to | |
7 | * return the last 4k of kernel messages, regardless of whether | |
8 | * they've been read or not. Added option to suppress kernel printk's | |
9 | * to the console. Added hook for sending the console messages | |
10 | * elsewhere, in preparation for a serial line console (someday). | |
11 | * Ted Ts'o, 2/11/93. | |
12 | * Modified for sysctl support, 1/8/97, Chris Horn. | |
40dc5651 | 13 | * Fixed SMP synchronization, 08/08/99, Manfred Spraul |
624dffcb | 14 | * manfred@colorfullife.com |
1da177e4 | 15 | * Rewrote bits to get rid of console_lock |
e1f8e874 | 16 | * 01Mar01 Andrew Morton |
1da177e4 LT |
17 | */ |
18 | ||
19 | #include <linux/kernel.h> | |
20 | #include <linux/mm.h> | |
21 | #include <linux/tty.h> | |
22 | #include <linux/tty_driver.h> | |
1da177e4 LT |
23 | #include <linux/console.h> |
24 | #include <linux/init.h> | |
bfe8df3d RD |
25 | #include <linux/jiffies.h> |
26 | #include <linux/nmi.h> | |
1da177e4 | 27 | #include <linux/module.h> |
3b9c0410 | 28 | #include <linux/moduleparam.h> |
1da177e4 | 29 | #include <linux/interrupt.h> /* For in_interrupt() */ |
1da177e4 LT |
30 | #include <linux/delay.h> |
31 | #include <linux/smp.h> | |
32 | #include <linux/security.h> | |
33 | #include <linux/bootmem.h> | |
162a7e75 | 34 | #include <linux/memblock.h> |
a27bb332 | 35 | #include <linux/aio.h> |
1da177e4 | 36 | #include <linux/syscalls.h> |
04d491ab | 37 | #include <linux/kexec.h> |
d37d39ae | 38 | #include <linux/kdb.h> |
3fff4c42 | 39 | #include <linux/ratelimit.h> |
456b565c | 40 | #include <linux/kmsg_dump.h> |
00234592 | 41 | #include <linux/syslog.h> |
034260d6 KC |
42 | #include <linux/cpu.h> |
43 | #include <linux/notifier.h> | |
fb842b00 | 44 | #include <linux/rculist.h> |
e11fea92 | 45 | #include <linux/poll.h> |
74876a98 | 46 | #include <linux/irq_work.h> |
196779b9 | 47 | #include <linux/utsname.h> |
1da177e4 LT |
48 | |
49 | #include <asm/uaccess.h> | |
50 | ||
95100358 JB |
51 | #define CREATE_TRACE_POINTS |
52 | #include <trace/events/printk.h> | |
53 | ||
d197c43d | 54 | #include "console_cmdline.h" |
bbeddf52 | 55 | #include "braille.h" |
d197c43d | 56 | |
1da177e4 | 57 | /* printk's without a loglevel use this.. */ |
5af5bcb8 | 58 | #define DEFAULT_MESSAGE_LOGLEVEL CONFIG_DEFAULT_MESSAGE_LOGLEVEL |
1da177e4 LT |
59 | |
60 | /* We show everything that is MORE important than this.. */ | |
61 | #define MINIMUM_CONSOLE_LOGLEVEL 1 /* Minimum loglevel we let people use */ | |
62 | #define DEFAULT_CONSOLE_LOGLEVEL 7 /* anything MORE serious than KERN_DEBUG */ | |
63 | ||
1da177e4 LT |
64 | int console_printk[4] = { |
65 | DEFAULT_CONSOLE_LOGLEVEL, /* console_loglevel */ | |
66 | DEFAULT_MESSAGE_LOGLEVEL, /* default_message_loglevel */ | |
67 | MINIMUM_CONSOLE_LOGLEVEL, /* minimum_console_loglevel */ | |
68 | DEFAULT_CONSOLE_LOGLEVEL, /* default_console_loglevel */ | |
69 | }; | |
70 | ||
1da177e4 | 71 | /* |
0bbfb7c2 | 72 | * Low level drivers may need that to know if they can schedule in |
1da177e4 LT |
73 | * their unblank() callback or not. So let's export it. |
74 | */ | |
75 | int oops_in_progress; | |
76 | EXPORT_SYMBOL(oops_in_progress); | |
77 | ||
78 | /* | |
79 | * console_sem protects the console_drivers list, and also | |
80 | * provides serialisation for access to the entire console | |
81 | * driver system. | |
82 | */ | |
5b8c4f23 | 83 | static DEFINE_SEMAPHORE(console_sem); |
1da177e4 | 84 | struct console *console_drivers; |
a29d1cfe IM |
85 | EXPORT_SYMBOL_GPL(console_drivers); |
86 | ||
daee7797 DV |
87 | #ifdef CONFIG_LOCKDEP |
88 | static struct lockdep_map console_lock_dep_map = { | |
89 | .name = "console_lock" | |
90 | }; | |
91 | #endif | |
92 | ||
1da177e4 LT |
93 | /* |
94 | * This is used for debugging the mess that is the VT code by | |
95 | * keeping track if we have the console semaphore held. It's | |
96 | * definitely not the perfect debug tool (we don't know if _WE_ | |
97 | * hold it are racing, but it helps tracking those weird code | |
98 | * path in the console code where we end up in places I want | |
99 | * locked without the console sempahore held | |
100 | */ | |
557240b4 | 101 | static int console_locked, console_suspended; |
1da177e4 | 102 | |
fe3d8ad3 FT |
103 | /* |
104 | * If exclusive_console is non-NULL then only this console is to be printed to. | |
105 | */ | |
106 | static struct console *exclusive_console; | |
107 | ||
1da177e4 LT |
108 | /* |
109 | * Array of consoles built from command line options (console=) | |
110 | */ | |
1da177e4 LT |
111 | |
112 | #define MAX_CMDLINECONSOLES 8 | |
113 | ||
114 | static struct console_cmdline console_cmdline[MAX_CMDLINECONSOLES]; | |
d197c43d | 115 | |
1da177e4 LT |
116 | static int selected_console = -1; |
117 | static int preferred_console = -1; | |
9e124fe1 MA |
118 | int console_set_on_cmdline; |
119 | EXPORT_SYMBOL(console_set_on_cmdline); | |
1da177e4 LT |
120 | |
121 | /* Flag: console code may call schedule() */ | |
122 | static int console_may_schedule; | |
123 | ||
7ff9554b KS |
124 | /* |
125 | * The printk log buffer consists of a chain of concatenated variable | |
126 | * length records. Every record starts with a record header, containing | |
127 | * the overall length of the record. | |
128 | * | |
129 | * The heads to the first and last entry in the buffer, as well as the | |
130 | * sequence numbers of these both entries are maintained when messages | |
131 | * are stored.. | |
132 | * | |
133 | * If the heads indicate available messages, the length in the header | |
134 | * tells the start next message. A length == 0 for the next message | |
135 | * indicates a wrap-around to the beginning of the buffer. | |
136 | * | |
137 | * Every record carries the monotonic timestamp in microseconds, as well as | |
138 | * the standard userspace syslog level and syslog facility. The usual | |
139 | * kernel messages use LOG_KERN; userspace-injected messages always carry | |
140 | * a matching syslog facility, by default LOG_USER. The origin of every | |
141 | * message can be reliably determined that way. | |
142 | * | |
143 | * The human readable log message directly follows the message header. The | |
144 | * length of the message text is stored in the header, the stored message | |
145 | * is not terminated. | |
146 | * | |
e11fea92 KS |
147 | * Optionally, a message can carry a dictionary of properties (key/value pairs), |
148 | * to provide userspace with a machine-readable message context. | |
149 | * | |
150 | * Examples for well-defined, commonly used property names are: | |
151 | * DEVICE=b12:8 device identifier | |
152 | * b12:8 block dev_t | |
153 | * c127:3 char dev_t | |
154 | * n8 netdev ifindex | |
155 | * +sound:card0 subsystem:devname | |
156 | * SUBSYSTEM=pci driver-core subsystem name | |
157 | * | |
158 | * Valid characters in property names are [a-zA-Z0-9.-_]. The plain text value | |
159 | * follows directly after a '=' character. Every property is terminated by | |
160 | * a '\0' character. The last property is not terminated. | |
161 | * | |
162 | * Example of a message structure: | |
163 | * 0000 ff 8f 00 00 00 00 00 00 monotonic time in nsec | |
164 | * 0008 34 00 record is 52 bytes long | |
165 | * 000a 0b 00 text is 11 bytes long | |
166 | * 000c 1f 00 dictionary is 23 bytes long | |
167 | * 000e 03 00 LOG_KERN (facility) LOG_ERR (level) | |
168 | * 0010 69 74 27 73 20 61 20 6c "it's a l" | |
169 | * 69 6e 65 "ine" | |
170 | * 001b 44 45 56 49 43 "DEVIC" | |
171 | * 45 3d 62 38 3a 32 00 44 "E=b8:2\0D" | |
172 | * 52 49 56 45 52 3d 62 75 "RIVER=bu" | |
173 | * 67 "g" | |
174 | * 0032 00 00 00 padding to next message header | |
175 | * | |
62e32ac3 | 176 | * The 'struct printk_log' buffer header must never be directly exported to |
e11fea92 KS |
177 | * userspace, it is a kernel-private implementation detail that might |
178 | * need to be changed in the future, when the requirements change. | |
179 | * | |
180 | * /dev/kmsg exports the structured data in the following line format: | |
181 | * "level,sequnum,timestamp;<message text>\n" | |
182 | * | |
183 | * The optional key/value pairs are attached as continuation lines starting | |
184 | * with a space character and terminated by a newline. All possible | |
185 | * non-prinatable characters are escaped in the "\xff" notation. | |
186 | * | |
187 | * Users of the export format should ignore possible additional values | |
188 | * separated by ',', and find the message after the ';' character. | |
7ff9554b KS |
189 | */ |
190 | ||
084681d1 | 191 | enum log_flags { |
5becfb1d KS |
192 | LOG_NOCONS = 1, /* already flushed, do not print to console */ |
193 | LOG_NEWLINE = 2, /* text ended with a newline */ | |
194 | LOG_PREFIX = 4, /* text started with a prefix */ | |
195 | LOG_CONT = 8, /* text is a fragment of a continuation line */ | |
084681d1 KS |
196 | }; |
197 | ||
62e32ac3 | 198 | struct printk_log { |
7ff9554b KS |
199 | u64 ts_nsec; /* timestamp in nanoseconds */ |
200 | u16 len; /* length of entire record */ | |
201 | u16 text_len; /* length of text buffer */ | |
202 | u16 dict_len; /* length of dictionary buffer */ | |
084681d1 KS |
203 | u8 facility; /* syslog facility */ |
204 | u8 flags:5; /* internal record flags */ | |
205 | u8 level:3; /* syslog level */ | |
7ff9554b KS |
206 | }; |
207 | ||
208 | /* | |
209 | * The logbuf_lock protects kmsg buffer, indices, counters. It is also | |
210 | * used in interesting ways to provide interlocking in console_unlock(); | |
211 | */ | |
212 | static DEFINE_RAW_SPINLOCK(logbuf_lock); | |
d59745ce | 213 | |
96efedf1 | 214 | #ifdef CONFIG_PRINTK |
dc72c32e | 215 | DECLARE_WAIT_QUEUE_HEAD(log_wait); |
7f3a781d KS |
216 | /* the next printk record to read by syslog(READ) or /proc/kmsg */ |
217 | static u64 syslog_seq; | |
218 | static u32 syslog_idx; | |
5becfb1d | 219 | static enum log_flags syslog_prev; |
eb02dac9 | 220 | static size_t syslog_partial; |
7ff9554b KS |
221 | |
222 | /* index and sequence number of the first record stored in the buffer */ | |
223 | static u64 log_first_seq; | |
224 | static u32 log_first_idx; | |
225 | ||
226 | /* index and sequence number of the next record to store in the buffer */ | |
227 | static u64 log_next_seq; | |
228 | static u32 log_next_idx; | |
229 | ||
eab07260 KS |
230 | /* the next printk record to write to the console */ |
231 | static u64 console_seq; | |
232 | static u32 console_idx; | |
233 | static enum log_flags console_prev; | |
234 | ||
7ff9554b KS |
235 | /* the next printk record to read after the last 'clear' command */ |
236 | static u64 clear_seq; | |
237 | static u32 clear_idx; | |
238 | ||
70498253 KS |
239 | #define PREFIX_MAX 32 |
240 | #define LOG_LINE_MAX 1024 - PREFIX_MAX | |
7f3a781d KS |
241 | |
242 | /* record buffer */ | |
6ebb017d | 243 | #if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) |
f8450fca SW |
244 | #define LOG_ALIGN 4 |
245 | #else | |
62e32ac3 | 246 | #define LOG_ALIGN __alignof__(struct printk_log) |
f8450fca | 247 | #endif |
7f3a781d | 248 | #define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT) |
f8450fca | 249 | static char __log_buf[__LOG_BUF_LEN] __aligned(LOG_ALIGN); |
7f3a781d KS |
250 | static char *log_buf = __log_buf; |
251 | static u32 log_buf_len = __LOG_BUF_LEN; | |
252 | ||
253 | /* cpu currently holding logbuf_lock */ | |
254 | static volatile unsigned int logbuf_cpu = UINT_MAX; | |
7ff9554b KS |
255 | |
256 | /* human readable text of the record */ | |
62e32ac3 | 257 | static char *log_text(const struct printk_log *msg) |
7ff9554b | 258 | { |
62e32ac3 | 259 | return (char *)msg + sizeof(struct printk_log); |
7ff9554b KS |
260 | } |
261 | ||
262 | /* optional key/value pair dictionary attached to the record */ | |
62e32ac3 | 263 | static char *log_dict(const struct printk_log *msg) |
7ff9554b | 264 | { |
62e32ac3 | 265 | return (char *)msg + sizeof(struct printk_log) + msg->text_len; |
7ff9554b KS |
266 | } |
267 | ||
268 | /* get record by index; idx must point to valid msg */ | |
62e32ac3 | 269 | static struct printk_log *log_from_idx(u32 idx) |
7ff9554b | 270 | { |
62e32ac3 | 271 | struct printk_log *msg = (struct printk_log *)(log_buf + idx); |
7ff9554b KS |
272 | |
273 | /* | |
274 | * A length == 0 record is the end of buffer marker. Wrap around and | |
275 | * read the message at the start of the buffer. | |
276 | */ | |
277 | if (!msg->len) | |
62e32ac3 | 278 | return (struct printk_log *)log_buf; |
7ff9554b KS |
279 | return msg; |
280 | } | |
281 | ||
282 | /* get next record; idx must point to valid msg */ | |
283 | static u32 log_next(u32 idx) | |
284 | { | |
62e32ac3 | 285 | struct printk_log *msg = (struct printk_log *)(log_buf + idx); |
7ff9554b KS |
286 | |
287 | /* length == 0 indicates the end of the buffer; wrap */ | |
288 | /* | |
289 | * A length == 0 record is the end of buffer marker. Wrap around and | |
290 | * read the message at the start of the buffer as *this* one, and | |
291 | * return the one after that. | |
292 | */ | |
293 | if (!msg->len) { | |
62e32ac3 | 294 | msg = (struct printk_log *)log_buf; |
7ff9554b KS |
295 | return msg->len; |
296 | } | |
297 | return idx + msg->len; | |
298 | } | |
299 | ||
7ff9554b KS |
300 | /* insert record into the buffer, discard old ones, update heads */ |
301 | static void log_store(int facility, int level, | |
084681d1 | 302 | enum log_flags flags, u64 ts_nsec, |
7ff9554b KS |
303 | const char *dict, u16 dict_len, |
304 | const char *text, u16 text_len) | |
305 | { | |
62e32ac3 | 306 | struct printk_log *msg; |
7ff9554b KS |
307 | u32 size, pad_len; |
308 | ||
309 | /* number of '\0' padding bytes to next message */ | |
62e32ac3 | 310 | size = sizeof(struct printk_log) + text_len + dict_len; |
7ff9554b KS |
311 | pad_len = (-size) & (LOG_ALIGN - 1); |
312 | size += pad_len; | |
313 | ||
314 | while (log_first_seq < log_next_seq) { | |
315 | u32 free; | |
316 | ||
317 | if (log_next_idx > log_first_idx) | |
318 | free = max(log_buf_len - log_next_idx, log_first_idx); | |
319 | else | |
320 | free = log_first_idx - log_next_idx; | |
321 | ||
62e32ac3 | 322 | if (free > size + sizeof(struct printk_log)) |
7ff9554b KS |
323 | break; |
324 | ||
325 | /* drop old messages until we have enough contiuous space */ | |
326 | log_first_idx = log_next(log_first_idx); | |
327 | log_first_seq++; | |
328 | } | |
329 | ||
62e32ac3 | 330 | if (log_next_idx + size + sizeof(struct printk_log) >= log_buf_len) { |
7ff9554b KS |
331 | /* |
332 | * This message + an additional empty header does not fit | |
333 | * at the end of the buffer. Add an empty header with len == 0 | |
334 | * to signify a wrap around. | |
335 | */ | |
62e32ac3 | 336 | memset(log_buf + log_next_idx, 0, sizeof(struct printk_log)); |
7ff9554b KS |
337 | log_next_idx = 0; |
338 | } | |
339 | ||
340 | /* fill message */ | |
62e32ac3 | 341 | msg = (struct printk_log *)(log_buf + log_next_idx); |
7ff9554b KS |
342 | memcpy(log_text(msg), text, text_len); |
343 | msg->text_len = text_len; | |
344 | memcpy(log_dict(msg), dict, dict_len); | |
345 | msg->dict_len = dict_len; | |
084681d1 KS |
346 | msg->facility = facility; |
347 | msg->level = level & 7; | |
348 | msg->flags = flags & 0x1f; | |
349 | if (ts_nsec > 0) | |
350 | msg->ts_nsec = ts_nsec; | |
351 | else | |
352 | msg->ts_nsec = local_clock(); | |
7ff9554b | 353 | memset(log_dict(msg) + dict_len, 0, pad_len); |
62e32ac3 | 354 | msg->len = sizeof(struct printk_log) + text_len + dict_len + pad_len; |
7ff9554b KS |
355 | |
356 | /* insert message */ | |
357 | log_next_idx += msg->len; | |
358 | log_next_seq++; | |
359 | } | |
d59745ce | 360 | |
637241a9 KC |
361 | #ifdef CONFIG_SECURITY_DMESG_RESTRICT |
362 | int dmesg_restrict = 1; | |
363 | #else | |
364 | int dmesg_restrict; | |
365 | #endif | |
366 | ||
367 | static int syslog_action_restricted(int type) | |
368 | { | |
369 | if (dmesg_restrict) | |
370 | return 1; | |
371 | /* | |
372 | * Unless restricted, we allow "read all" and "get buffer size" | |
373 | * for everybody. | |
374 | */ | |
375 | return type != SYSLOG_ACTION_READ_ALL && | |
376 | type != SYSLOG_ACTION_SIZE_BUFFER; | |
377 | } | |
378 | ||
379 | static int check_syslog_permissions(int type, bool from_file) | |
380 | { | |
381 | /* | |
382 | * If this is from /proc/kmsg and we've already opened it, then we've | |
383 | * already done the capabilities checks at open time. | |
384 | */ | |
385 | if (from_file && type != SYSLOG_ACTION_OPEN) | |
386 | return 0; | |
387 | ||
388 | if (syslog_action_restricted(type)) { | |
389 | if (capable(CAP_SYSLOG)) | |
390 | return 0; | |
391 | /* | |
392 | * For historical reasons, accept CAP_SYS_ADMIN too, with | |
393 | * a warning. | |
394 | */ | |
395 | if (capable(CAP_SYS_ADMIN)) { | |
396 | pr_warn_once("%s (%d): Attempt to access syslog with " | |
397 | "CAP_SYS_ADMIN but no CAP_SYSLOG " | |
398 | "(deprecated).\n", | |
399 | current->comm, task_pid_nr(current)); | |
400 | return 0; | |
401 | } | |
402 | return -EPERM; | |
403 | } | |
404 | return security_syslog(type); | |
405 | } | |
406 | ||
407 | ||
e11fea92 KS |
408 | /* /dev/kmsg - userspace message inject/listen interface */ |
409 | struct devkmsg_user { | |
410 | u64 seq; | |
411 | u32 idx; | |
d39f3d77 | 412 | enum log_flags prev; |
e11fea92 KS |
413 | struct mutex lock; |
414 | char buf[8192]; | |
415 | }; | |
416 | ||
417 | static ssize_t devkmsg_writev(struct kiocb *iocb, const struct iovec *iv, | |
418 | unsigned long count, loff_t pos) | |
419 | { | |
420 | char *buf, *line; | |
421 | int i; | |
422 | int level = default_message_loglevel; | |
423 | int facility = 1; /* LOG_USER */ | |
424 | size_t len = iov_length(iv, count); | |
425 | ssize_t ret = len; | |
426 | ||
427 | if (len > LOG_LINE_MAX) | |
428 | return -EINVAL; | |
429 | buf = kmalloc(len+1, GFP_KERNEL); | |
430 | if (buf == NULL) | |
431 | return -ENOMEM; | |
432 | ||
433 | line = buf; | |
434 | for (i = 0; i < count; i++) { | |
cdf53441 KS |
435 | if (copy_from_user(line, iv[i].iov_base, iv[i].iov_len)) { |
436 | ret = -EFAULT; | |
e11fea92 | 437 | goto out; |
cdf53441 | 438 | } |
e11fea92 KS |
439 | line += iv[i].iov_len; |
440 | } | |
441 | ||
442 | /* | |
443 | * Extract and skip the syslog prefix <[0-9]*>. Coming from userspace | |
444 | * the decimal value represents 32bit, the lower 3 bit are the log | |
445 | * level, the rest are the log facility. | |
446 | * | |
447 | * If no prefix or no userspace facility is specified, we | |
448 | * enforce LOG_USER, to be able to reliably distinguish | |
449 | * kernel-generated messages from userspace-injected ones. | |
450 | */ | |
451 | line = buf; | |
452 | if (line[0] == '<') { | |
453 | char *endp = NULL; | |
454 | ||
455 | i = simple_strtoul(line+1, &endp, 10); | |
456 | if (endp && endp[0] == '>') { | |
457 | level = i & 7; | |
458 | if (i >> 3) | |
459 | facility = i >> 3; | |
460 | endp++; | |
461 | len -= endp - line; | |
462 | line = endp; | |
463 | } | |
464 | } | |
465 | line[len] = '\0'; | |
466 | ||
467 | printk_emit(facility, level, NULL, 0, "%s", line); | |
468 | out: | |
469 | kfree(buf); | |
470 | return ret; | |
471 | } | |
472 | ||
473 | static ssize_t devkmsg_read(struct file *file, char __user *buf, | |
474 | size_t count, loff_t *ppos) | |
475 | { | |
476 | struct devkmsg_user *user = file->private_data; | |
62e32ac3 | 477 | struct printk_log *msg; |
5fc32490 | 478 | u64 ts_usec; |
e11fea92 | 479 | size_t i; |
d39f3d77 | 480 | char cont = '-'; |
e11fea92 KS |
481 | size_t len; |
482 | ssize_t ret; | |
483 | ||
484 | if (!user) | |
485 | return -EBADF; | |
486 | ||
4a77a5a0 YL |
487 | ret = mutex_lock_interruptible(&user->lock); |
488 | if (ret) | |
489 | return ret; | |
5c53d819 | 490 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
491 | while (user->seq == log_next_seq) { |
492 | if (file->f_flags & O_NONBLOCK) { | |
493 | ret = -EAGAIN; | |
5c53d819 | 494 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
495 | goto out; |
496 | } | |
497 | ||
5c53d819 | 498 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
499 | ret = wait_event_interruptible(log_wait, |
500 | user->seq != log_next_seq); | |
501 | if (ret) | |
502 | goto out; | |
5c53d819 | 503 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
504 | } |
505 | ||
506 | if (user->seq < log_first_seq) { | |
507 | /* our last seen message is gone, return error and reset */ | |
508 | user->idx = log_first_idx; | |
509 | user->seq = log_first_seq; | |
510 | ret = -EPIPE; | |
5c53d819 | 511 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
512 | goto out; |
513 | } | |
514 | ||
515 | msg = log_from_idx(user->idx); | |
5fc32490 KS |
516 | ts_usec = msg->ts_nsec; |
517 | do_div(ts_usec, 1000); | |
d39f3d77 KS |
518 | |
519 | /* | |
520 | * If we couldn't merge continuation line fragments during the print, | |
521 | * export the stored flags to allow an optional external merge of the | |
522 | * records. Merging the records isn't always neccessarily correct, like | |
523 | * when we hit a race during printing. In most cases though, it produces | |
524 | * better readable output. 'c' in the record flags mark the first | |
525 | * fragment of a line, '+' the following. | |
526 | */ | |
527 | if (msg->flags & LOG_CONT && !(user->prev & LOG_CONT)) | |
528 | cont = 'c'; | |
529 | else if ((msg->flags & LOG_CONT) || | |
530 | ((user->prev & LOG_CONT) && !(msg->flags & LOG_PREFIX))) | |
531 | cont = '+'; | |
532 | ||
533 | len = sprintf(user->buf, "%u,%llu,%llu,%c;", | |
534 | (msg->facility << 3) | msg->level, | |
535 | user->seq, ts_usec, cont); | |
536 | user->prev = msg->flags; | |
e11fea92 KS |
537 | |
538 | /* escape non-printable characters */ | |
539 | for (i = 0; i < msg->text_len; i++) { | |
3ce9a7c0 | 540 | unsigned char c = log_text(msg)[i]; |
e11fea92 | 541 | |
e3f5a5f2 | 542 | if (c < ' ' || c >= 127 || c == '\\') |
e11fea92 KS |
543 | len += sprintf(user->buf + len, "\\x%02x", c); |
544 | else | |
545 | user->buf[len++] = c; | |
546 | } | |
547 | user->buf[len++] = '\n'; | |
548 | ||
549 | if (msg->dict_len) { | |
550 | bool line = true; | |
551 | ||
552 | for (i = 0; i < msg->dict_len; i++) { | |
3ce9a7c0 | 553 | unsigned char c = log_dict(msg)[i]; |
e11fea92 KS |
554 | |
555 | if (line) { | |
556 | user->buf[len++] = ' '; | |
557 | line = false; | |
558 | } | |
559 | ||
560 | if (c == '\0') { | |
561 | user->buf[len++] = '\n'; | |
562 | line = true; | |
563 | continue; | |
564 | } | |
565 | ||
e3f5a5f2 | 566 | if (c < ' ' || c >= 127 || c == '\\') { |
e11fea92 KS |
567 | len += sprintf(user->buf + len, "\\x%02x", c); |
568 | continue; | |
569 | } | |
570 | ||
571 | user->buf[len++] = c; | |
572 | } | |
573 | user->buf[len++] = '\n'; | |
574 | } | |
575 | ||
576 | user->idx = log_next(user->idx); | |
577 | user->seq++; | |
5c53d819 | 578 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
579 | |
580 | if (len > count) { | |
581 | ret = -EINVAL; | |
582 | goto out; | |
583 | } | |
584 | ||
585 | if (copy_to_user(buf, user->buf, len)) { | |
586 | ret = -EFAULT; | |
587 | goto out; | |
588 | } | |
589 | ret = len; | |
590 | out: | |
591 | mutex_unlock(&user->lock); | |
592 | return ret; | |
593 | } | |
594 | ||
595 | static loff_t devkmsg_llseek(struct file *file, loff_t offset, int whence) | |
596 | { | |
597 | struct devkmsg_user *user = file->private_data; | |
598 | loff_t ret = 0; | |
599 | ||
600 | if (!user) | |
601 | return -EBADF; | |
602 | if (offset) | |
603 | return -ESPIPE; | |
604 | ||
5c53d819 | 605 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
606 | switch (whence) { |
607 | case SEEK_SET: | |
608 | /* the first record */ | |
609 | user->idx = log_first_idx; | |
610 | user->seq = log_first_seq; | |
611 | break; | |
612 | case SEEK_DATA: | |
613 | /* | |
614 | * The first record after the last SYSLOG_ACTION_CLEAR, | |
615 | * like issued by 'dmesg -c'. Reading /dev/kmsg itself | |
616 | * changes no global state, and does not clear anything. | |
617 | */ | |
618 | user->idx = clear_idx; | |
619 | user->seq = clear_seq; | |
620 | break; | |
621 | case SEEK_END: | |
622 | /* after the last record */ | |
623 | user->idx = log_next_idx; | |
624 | user->seq = log_next_seq; | |
625 | break; | |
626 | default: | |
627 | ret = -EINVAL; | |
628 | } | |
5c53d819 | 629 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
630 | return ret; |
631 | } | |
632 | ||
633 | static unsigned int devkmsg_poll(struct file *file, poll_table *wait) | |
634 | { | |
635 | struct devkmsg_user *user = file->private_data; | |
636 | int ret = 0; | |
637 | ||
638 | if (!user) | |
639 | return POLLERR|POLLNVAL; | |
640 | ||
641 | poll_wait(file, &log_wait, wait); | |
642 | ||
5c53d819 | 643 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
644 | if (user->seq < log_next_seq) { |
645 | /* return error when data has vanished underneath us */ | |
646 | if (user->seq < log_first_seq) | |
647 | ret = POLLIN|POLLRDNORM|POLLERR|POLLPRI; | |
0a285317 NK |
648 | else |
649 | ret = POLLIN|POLLRDNORM; | |
e11fea92 | 650 | } |
5c53d819 | 651 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
652 | |
653 | return ret; | |
654 | } | |
655 | ||
656 | static int devkmsg_open(struct inode *inode, struct file *file) | |
657 | { | |
658 | struct devkmsg_user *user; | |
659 | int err; | |
660 | ||
661 | /* write-only does not need any file context */ | |
662 | if ((file->f_flags & O_ACCMODE) == O_WRONLY) | |
663 | return 0; | |
664 | ||
637241a9 KC |
665 | err = check_syslog_permissions(SYSLOG_ACTION_READ_ALL, |
666 | SYSLOG_FROM_READER); | |
e11fea92 KS |
667 | if (err) |
668 | return err; | |
669 | ||
670 | user = kmalloc(sizeof(struct devkmsg_user), GFP_KERNEL); | |
671 | if (!user) | |
672 | return -ENOMEM; | |
673 | ||
674 | mutex_init(&user->lock); | |
675 | ||
5c53d819 | 676 | raw_spin_lock_irq(&logbuf_lock); |
e11fea92 KS |
677 | user->idx = log_first_idx; |
678 | user->seq = log_first_seq; | |
5c53d819 | 679 | raw_spin_unlock_irq(&logbuf_lock); |
e11fea92 KS |
680 | |
681 | file->private_data = user; | |
682 | return 0; | |
683 | } | |
684 | ||
685 | static int devkmsg_release(struct inode *inode, struct file *file) | |
686 | { | |
687 | struct devkmsg_user *user = file->private_data; | |
688 | ||
689 | if (!user) | |
690 | return 0; | |
691 | ||
692 | mutex_destroy(&user->lock); | |
693 | kfree(user); | |
694 | return 0; | |
695 | } | |
696 | ||
697 | const struct file_operations kmsg_fops = { | |
698 | .open = devkmsg_open, | |
699 | .read = devkmsg_read, | |
700 | .aio_write = devkmsg_writev, | |
701 | .llseek = devkmsg_llseek, | |
702 | .poll = devkmsg_poll, | |
703 | .release = devkmsg_release, | |
704 | }; | |
705 | ||
04d491ab NH |
706 | #ifdef CONFIG_KEXEC |
707 | /* | |
4c1ace64 | 708 | * This appends the listed symbols to /proc/vmcore |
04d491ab | 709 | * |
4c1ace64 | 710 | * /proc/vmcore is used by various utilities, like crash and makedumpfile to |
04d491ab NH |
711 | * obtain access to symbols that are otherwise very difficult to locate. These |
712 | * symbols are specifically used so that utilities can access and extract the | |
713 | * dmesg log from a vmcore file after a crash. | |
714 | */ | |
715 | void log_buf_kexec_setup(void) | |
716 | { | |
717 | VMCOREINFO_SYMBOL(log_buf); | |
04d491ab | 718 | VMCOREINFO_SYMBOL(log_buf_len); |
7ff9554b KS |
719 | VMCOREINFO_SYMBOL(log_first_idx); |
720 | VMCOREINFO_SYMBOL(log_next_idx); | |
6791457a | 721 | /* |
62e32ac3 | 722 | * Export struct printk_log size and field offsets. User space tools can |
6791457a VG |
723 | * parse it and detect any changes to structure down the line. |
724 | */ | |
62e32ac3 JP |
725 | VMCOREINFO_STRUCT_SIZE(printk_log); |
726 | VMCOREINFO_OFFSET(printk_log, ts_nsec); | |
727 | VMCOREINFO_OFFSET(printk_log, len); | |
728 | VMCOREINFO_OFFSET(printk_log, text_len); | |
729 | VMCOREINFO_OFFSET(printk_log, dict_len); | |
04d491ab NH |
730 | } |
731 | #endif | |
732 | ||
162a7e75 MT |
733 | /* requested log_buf_len from kernel cmdline */ |
734 | static unsigned long __initdata new_log_buf_len; | |
735 | ||
736 | /* save requested log_buf_len since it's too early to process it */ | |
1da177e4 LT |
737 | static int __init log_buf_len_setup(char *str) |
738 | { | |
eed4a2ab | 739 | unsigned size = memparse(str, &str); |
1da177e4 LT |
740 | |
741 | if (size) | |
742 | size = roundup_pow_of_two(size); | |
162a7e75 MT |
743 | if (size > log_buf_len) |
744 | new_log_buf_len = size; | |
745 | ||
746 | return 0; | |
1da177e4 | 747 | } |
162a7e75 MT |
748 | early_param("log_buf_len", log_buf_len_setup); |
749 | ||
750 | void __init setup_log_buf(int early) | |
751 | { | |
752 | unsigned long flags; | |
162a7e75 MT |
753 | char *new_log_buf; |
754 | int free; | |
755 | ||
756 | if (!new_log_buf_len) | |
757 | return; | |
1da177e4 | 758 | |
162a7e75 | 759 | if (early) { |
9da791df SS |
760 | new_log_buf = |
761 | memblock_virt_alloc(new_log_buf_len, PAGE_SIZE); | |
162a7e75 | 762 | } else { |
9da791df | 763 | new_log_buf = memblock_virt_alloc_nopanic(new_log_buf_len, 0); |
162a7e75 MT |
764 | } |
765 | ||
766 | if (unlikely(!new_log_buf)) { | |
767 | pr_err("log_buf_len: %ld bytes not available\n", | |
768 | new_log_buf_len); | |
769 | return; | |
770 | } | |
771 | ||
07354eb1 | 772 | raw_spin_lock_irqsave(&logbuf_lock, flags); |
162a7e75 MT |
773 | log_buf_len = new_log_buf_len; |
774 | log_buf = new_log_buf; | |
775 | new_log_buf_len = 0; | |
7ff9554b KS |
776 | free = __LOG_BUF_LEN - log_next_idx; |
777 | memcpy(log_buf, __log_buf, __LOG_BUF_LEN); | |
07354eb1 | 778 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
162a7e75 MT |
779 | |
780 | pr_info("log_buf_len: %d\n", log_buf_len); | |
781 | pr_info("early log buf free: %d(%d%%)\n", | |
782 | free, (free * 100) / __LOG_BUF_LEN); | |
783 | } | |
1da177e4 | 784 | |
2fa72c8f AC |
785 | static bool __read_mostly ignore_loglevel; |
786 | ||
787 | static int __init ignore_loglevel_setup(char *str) | |
788 | { | |
789 | ignore_loglevel = 1; | |
27083bac | 790 | pr_info("debug: ignoring loglevel setting.\n"); |
2fa72c8f AC |
791 | |
792 | return 0; | |
793 | } | |
794 | ||
795 | early_param("ignore_loglevel", ignore_loglevel_setup); | |
796 | module_param(ignore_loglevel, bool, S_IRUGO | S_IWUSR); | |
797 | MODULE_PARM_DESC(ignore_loglevel, "ignore loglevel setting, to" | |
798 | "print all kernel messages to the console."); | |
799 | ||
bfe8df3d RD |
800 | #ifdef CONFIG_BOOT_PRINTK_DELAY |
801 | ||
674dff65 | 802 | static int boot_delay; /* msecs delay after each printk during bootup */ |
3a3b6ed2 | 803 | static unsigned long long loops_per_msec; /* based on boot_delay */ |
bfe8df3d RD |
804 | |
805 | static int __init boot_delay_setup(char *str) | |
806 | { | |
807 | unsigned long lpj; | |
bfe8df3d RD |
808 | |
809 | lpj = preset_lpj ? preset_lpj : 1000000; /* some guess */ | |
810 | loops_per_msec = (unsigned long long)lpj / 1000 * HZ; | |
811 | ||
812 | get_option(&str, &boot_delay); | |
813 | if (boot_delay > 10 * 1000) | |
814 | boot_delay = 0; | |
815 | ||
3a3b6ed2 DY |
816 | pr_debug("boot_delay: %u, preset_lpj: %ld, lpj: %lu, " |
817 | "HZ: %d, loops_per_msec: %llu\n", | |
818 | boot_delay, preset_lpj, lpj, HZ, loops_per_msec); | |
29e9d225 | 819 | return 0; |
bfe8df3d | 820 | } |
29e9d225 | 821 | early_param("boot_delay", boot_delay_setup); |
bfe8df3d | 822 | |
2fa72c8f | 823 | static void boot_delay_msec(int level) |
bfe8df3d RD |
824 | { |
825 | unsigned long long k; | |
826 | unsigned long timeout; | |
827 | ||
2fa72c8f AC |
828 | if ((boot_delay == 0 || system_state != SYSTEM_BOOTING) |
829 | || (level >= console_loglevel && !ignore_loglevel)) { | |
bfe8df3d | 830 | return; |
2fa72c8f | 831 | } |
bfe8df3d | 832 | |
3a3b6ed2 | 833 | k = (unsigned long long)loops_per_msec * boot_delay; |
bfe8df3d RD |
834 | |
835 | timeout = jiffies + msecs_to_jiffies(boot_delay); | |
836 | while (k) { | |
837 | k--; | |
838 | cpu_relax(); | |
839 | /* | |
840 | * use (volatile) jiffies to prevent | |
841 | * compiler reduction; loop termination via jiffies | |
842 | * is secondary and may or may not happen. | |
843 | */ | |
844 | if (time_after(jiffies, timeout)) | |
845 | break; | |
846 | touch_nmi_watchdog(); | |
847 | } | |
848 | } | |
849 | #else | |
2fa72c8f | 850 | static inline void boot_delay_msec(int level) |
bfe8df3d RD |
851 | { |
852 | } | |
853 | #endif | |
854 | ||
7ff9554b KS |
855 | #if defined(CONFIG_PRINTK_TIME) |
856 | static bool printk_time = 1; | |
857 | #else | |
858 | static bool printk_time; | |
859 | #endif | |
860 | module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR); | |
861 | ||
084681d1 KS |
862 | static size_t print_time(u64 ts, char *buf) |
863 | { | |
864 | unsigned long rem_nsec; | |
865 | ||
866 | if (!printk_time) | |
867 | return 0; | |
868 | ||
35dac27c RD |
869 | rem_nsec = do_div(ts, 1000000000); |
870 | ||
084681d1 | 871 | if (!buf) |
35dac27c | 872 | return snprintf(NULL, 0, "[%5lu.000000] ", (unsigned long)ts); |
084681d1 | 873 | |
084681d1 KS |
874 | return sprintf(buf, "[%5lu.%06lu] ", |
875 | (unsigned long)ts, rem_nsec / 1000); | |
876 | } | |
877 | ||
62e32ac3 | 878 | static size_t print_prefix(const struct printk_log *msg, bool syslog, char *buf) |
649e6ee3 | 879 | { |
3ce9a7c0 | 880 | size_t len = 0; |
43a73a50 | 881 | unsigned int prefix = (msg->facility << 3) | msg->level; |
649e6ee3 | 882 | |
3ce9a7c0 KS |
883 | if (syslog) { |
884 | if (buf) { | |
43a73a50 | 885 | len += sprintf(buf, "<%u>", prefix); |
3ce9a7c0 KS |
886 | } else { |
887 | len += 3; | |
43a73a50 KS |
888 | if (prefix > 999) |
889 | len += 3; | |
890 | else if (prefix > 99) | |
891 | len += 2; | |
892 | else if (prefix > 9) | |
3ce9a7c0 KS |
893 | len++; |
894 | } | |
895 | } | |
649e6ee3 | 896 | |
084681d1 | 897 | len += print_time(msg->ts_nsec, buf ? buf + len : NULL); |
3ce9a7c0 | 898 | return len; |
649e6ee3 KS |
899 | } |
900 | ||
62e32ac3 | 901 | static size_t msg_print_text(const struct printk_log *msg, enum log_flags prev, |
5becfb1d | 902 | bool syslog, char *buf, size_t size) |
7ff9554b | 903 | { |
3ce9a7c0 KS |
904 | const char *text = log_text(msg); |
905 | size_t text_size = msg->text_len; | |
5becfb1d KS |
906 | bool prefix = true; |
907 | bool newline = true; | |
3ce9a7c0 KS |
908 | size_t len = 0; |
909 | ||
5becfb1d KS |
910 | if ((prev & LOG_CONT) && !(msg->flags & LOG_PREFIX)) |
911 | prefix = false; | |
912 | ||
913 | if (msg->flags & LOG_CONT) { | |
914 | if ((prev & LOG_CONT) && !(prev & LOG_NEWLINE)) | |
915 | prefix = false; | |
916 | ||
917 | if (!(msg->flags & LOG_NEWLINE)) | |
918 | newline = false; | |
919 | } | |
920 | ||
3ce9a7c0 KS |
921 | do { |
922 | const char *next = memchr(text, '\n', text_size); | |
923 | size_t text_len; | |
924 | ||
925 | if (next) { | |
926 | text_len = next - text; | |
927 | next++; | |
928 | text_size -= next - text; | |
929 | } else { | |
930 | text_len = text_size; | |
931 | } | |
7ff9554b | 932 | |
3ce9a7c0 KS |
933 | if (buf) { |
934 | if (print_prefix(msg, syslog, NULL) + | |
70498253 | 935 | text_len + 1 >= size - len) |
3ce9a7c0 | 936 | break; |
7ff9554b | 937 | |
5becfb1d KS |
938 | if (prefix) |
939 | len += print_prefix(msg, syslog, buf + len); | |
3ce9a7c0 KS |
940 | memcpy(buf + len, text, text_len); |
941 | len += text_len; | |
5becfb1d KS |
942 | if (next || newline) |
943 | buf[len++] = '\n'; | |
3ce9a7c0 KS |
944 | } else { |
945 | /* SYSLOG_ACTION_* buffer size only calculation */ | |
5becfb1d KS |
946 | if (prefix) |
947 | len += print_prefix(msg, syslog, NULL); | |
948 | len += text_len; | |
949 | if (next || newline) | |
950 | len++; | |
3ce9a7c0 | 951 | } |
7ff9554b | 952 | |
5becfb1d | 953 | prefix = true; |
3ce9a7c0 KS |
954 | text = next; |
955 | } while (text); | |
7ff9554b | 956 | |
7ff9554b KS |
957 | return len; |
958 | } | |
959 | ||
960 | static int syslog_print(char __user *buf, int size) | |
961 | { | |
962 | char *text; | |
62e32ac3 | 963 | struct printk_log *msg; |
116e90b2 | 964 | int len = 0; |
7ff9554b | 965 | |
70498253 | 966 | text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL); |
7ff9554b KS |
967 | if (!text) |
968 | return -ENOMEM; | |
969 | ||
116e90b2 JB |
970 | while (size > 0) { |
971 | size_t n; | |
eb02dac9 | 972 | size_t skip; |
116e90b2 JB |
973 | |
974 | raw_spin_lock_irq(&logbuf_lock); | |
975 | if (syslog_seq < log_first_seq) { | |
976 | /* messages are gone, move to first one */ | |
977 | syslog_seq = log_first_seq; | |
978 | syslog_idx = log_first_idx; | |
5becfb1d | 979 | syslog_prev = 0; |
eb02dac9 | 980 | syslog_partial = 0; |
116e90b2 JB |
981 | } |
982 | if (syslog_seq == log_next_seq) { | |
983 | raw_spin_unlock_irq(&logbuf_lock); | |
984 | break; | |
985 | } | |
eb02dac9 KS |
986 | |
987 | skip = syslog_partial; | |
116e90b2 | 988 | msg = log_from_idx(syslog_idx); |
70498253 KS |
989 | n = msg_print_text(msg, syslog_prev, true, text, |
990 | LOG_LINE_MAX + PREFIX_MAX); | |
eb02dac9 KS |
991 | if (n - syslog_partial <= size) { |
992 | /* message fits into buffer, move forward */ | |
116e90b2 JB |
993 | syslog_idx = log_next(syslog_idx); |
994 | syslog_seq++; | |
5becfb1d | 995 | syslog_prev = msg->flags; |
eb02dac9 KS |
996 | n -= syslog_partial; |
997 | syslog_partial = 0; | |
998 | } else if (!len){ | |
999 | /* partial read(), remember position */ | |
1000 | n = size; | |
1001 | syslog_partial += n; | |
116e90b2 JB |
1002 | } else |
1003 | n = 0; | |
1004 | raw_spin_unlock_irq(&logbuf_lock); | |
1005 | ||
1006 | if (!n) | |
1007 | break; | |
1008 | ||
eb02dac9 | 1009 | if (copy_to_user(buf, text + skip, n)) { |
116e90b2 JB |
1010 | if (!len) |
1011 | len = -EFAULT; | |
1012 | break; | |
1013 | } | |
eb02dac9 KS |
1014 | |
1015 | len += n; | |
1016 | size -= n; | |
1017 | buf += n; | |
7ff9554b | 1018 | } |
7ff9554b KS |
1019 | |
1020 | kfree(text); | |
1021 | return len; | |
1022 | } | |
1023 | ||
1024 | static int syslog_print_all(char __user *buf, int size, bool clear) | |
1025 | { | |
1026 | char *text; | |
1027 | int len = 0; | |
1028 | ||
70498253 | 1029 | text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL); |
7ff9554b KS |
1030 | if (!text) |
1031 | return -ENOMEM; | |
1032 | ||
1033 | raw_spin_lock_irq(&logbuf_lock); | |
1034 | if (buf) { | |
1035 | u64 next_seq; | |
1036 | u64 seq; | |
1037 | u32 idx; | |
5becfb1d | 1038 | enum log_flags prev; |
7ff9554b KS |
1039 | |
1040 | if (clear_seq < log_first_seq) { | |
1041 | /* messages are gone, move to first available one */ | |
1042 | clear_seq = log_first_seq; | |
1043 | clear_idx = log_first_idx; | |
1044 | } | |
1045 | ||
1046 | /* | |
1047 | * Find first record that fits, including all following records, | |
1048 | * into the user-provided buffer for this dump. | |
e2ae715d | 1049 | */ |
7ff9554b KS |
1050 | seq = clear_seq; |
1051 | idx = clear_idx; | |
5becfb1d | 1052 | prev = 0; |
7ff9554b | 1053 | while (seq < log_next_seq) { |
62e32ac3 | 1054 | struct printk_log *msg = log_from_idx(idx); |
3ce9a7c0 | 1055 | |
5becfb1d | 1056 | len += msg_print_text(msg, prev, true, NULL, 0); |
e3756477 | 1057 | prev = msg->flags; |
7ff9554b KS |
1058 | idx = log_next(idx); |
1059 | seq++; | |
1060 | } | |
e2ae715d KS |
1061 | |
1062 | /* move first record forward until length fits into the buffer */ | |
7ff9554b KS |
1063 | seq = clear_seq; |
1064 | idx = clear_idx; | |
5becfb1d | 1065 | prev = 0; |
7ff9554b | 1066 | while (len > size && seq < log_next_seq) { |
62e32ac3 | 1067 | struct printk_log *msg = log_from_idx(idx); |
3ce9a7c0 | 1068 | |
5becfb1d | 1069 | len -= msg_print_text(msg, prev, true, NULL, 0); |
e3756477 | 1070 | prev = msg->flags; |
7ff9554b KS |
1071 | idx = log_next(idx); |
1072 | seq++; | |
1073 | } | |
1074 | ||
e2ae715d | 1075 | /* last message fitting into this dump */ |
7ff9554b KS |
1076 | next_seq = log_next_seq; |
1077 | ||
1078 | len = 0; | |
5becfb1d | 1079 | prev = 0; |
7ff9554b | 1080 | while (len >= 0 && seq < next_seq) { |
62e32ac3 | 1081 | struct printk_log *msg = log_from_idx(idx); |
7ff9554b KS |
1082 | int textlen; |
1083 | ||
70498253 KS |
1084 | textlen = msg_print_text(msg, prev, true, text, |
1085 | LOG_LINE_MAX + PREFIX_MAX); | |
7ff9554b KS |
1086 | if (textlen < 0) { |
1087 | len = textlen; | |
1088 | break; | |
1089 | } | |
1090 | idx = log_next(idx); | |
1091 | seq++; | |
5becfb1d | 1092 | prev = msg->flags; |
7ff9554b KS |
1093 | |
1094 | raw_spin_unlock_irq(&logbuf_lock); | |
1095 | if (copy_to_user(buf + len, text, textlen)) | |
1096 | len = -EFAULT; | |
1097 | else | |
1098 | len += textlen; | |
1099 | raw_spin_lock_irq(&logbuf_lock); | |
1100 | ||
1101 | if (seq < log_first_seq) { | |
1102 | /* messages are gone, move to next one */ | |
1103 | seq = log_first_seq; | |
1104 | idx = log_first_idx; | |
5becfb1d | 1105 | prev = 0; |
7ff9554b KS |
1106 | } |
1107 | } | |
1108 | } | |
1109 | ||
1110 | if (clear) { | |
1111 | clear_seq = log_next_seq; | |
1112 | clear_idx = log_next_idx; | |
1113 | } | |
1114 | raw_spin_unlock_irq(&logbuf_lock); | |
1115 | ||
1116 | kfree(text); | |
1117 | return len; | |
1118 | } | |
1119 | ||
00234592 | 1120 | int do_syslog(int type, char __user *buf, int len, bool from_file) |
1da177e4 | 1121 | { |
7ff9554b KS |
1122 | bool clear = false; |
1123 | static int saved_console_loglevel = -1; | |
ee24aebf | 1124 | int error; |
1da177e4 | 1125 | |
ee24aebf LT |
1126 | error = check_syslog_permissions(type, from_file); |
1127 | if (error) | |
1128 | goto out; | |
12b3052c EP |
1129 | |
1130 | error = security_syslog(type); | |
1da177e4 LT |
1131 | if (error) |
1132 | return error; | |
1133 | ||
1134 | switch (type) { | |
d78ca3cd | 1135 | case SYSLOG_ACTION_CLOSE: /* Close log */ |
1da177e4 | 1136 | break; |
d78ca3cd | 1137 | case SYSLOG_ACTION_OPEN: /* Open log */ |
1da177e4 | 1138 | break; |
d78ca3cd | 1139 | case SYSLOG_ACTION_READ: /* Read from log */ |
1da177e4 LT |
1140 | error = -EINVAL; |
1141 | if (!buf || len < 0) | |
1142 | goto out; | |
1143 | error = 0; | |
1144 | if (!len) | |
1145 | goto out; | |
1146 | if (!access_ok(VERIFY_WRITE, buf, len)) { | |
1147 | error = -EFAULT; | |
1148 | goto out; | |
1149 | } | |
40dc5651 | 1150 | error = wait_event_interruptible(log_wait, |
7ff9554b | 1151 | syslog_seq != log_next_seq); |
cb424ffe | 1152 | if (error) |
1da177e4 | 1153 | goto out; |
7ff9554b | 1154 | error = syslog_print(buf, len); |
1da177e4 | 1155 | break; |
d78ca3cd KC |
1156 | /* Read/clear last kernel messages */ |
1157 | case SYSLOG_ACTION_READ_CLEAR: | |
7ff9554b | 1158 | clear = true; |
1da177e4 | 1159 | /* FALL THRU */ |
d78ca3cd KC |
1160 | /* Read last kernel messages */ |
1161 | case SYSLOG_ACTION_READ_ALL: | |
1da177e4 LT |
1162 | error = -EINVAL; |
1163 | if (!buf || len < 0) | |
1164 | goto out; | |
1165 | error = 0; | |
1166 | if (!len) | |
1167 | goto out; | |
1168 | if (!access_ok(VERIFY_WRITE, buf, len)) { | |
1169 | error = -EFAULT; | |
1170 | goto out; | |
1171 | } | |
7ff9554b | 1172 | error = syslog_print_all(buf, len, clear); |
1da177e4 | 1173 | break; |
d78ca3cd KC |
1174 | /* Clear ring buffer */ |
1175 | case SYSLOG_ACTION_CLEAR: | |
7ff9554b | 1176 | syslog_print_all(NULL, 0, true); |
4661e356 | 1177 | break; |
d78ca3cd KC |
1178 | /* Disable logging to console */ |
1179 | case SYSLOG_ACTION_CONSOLE_OFF: | |
1aaad49e FP |
1180 | if (saved_console_loglevel == -1) |
1181 | saved_console_loglevel = console_loglevel; | |
1da177e4 LT |
1182 | console_loglevel = minimum_console_loglevel; |
1183 | break; | |
d78ca3cd KC |
1184 | /* Enable logging to console */ |
1185 | case SYSLOG_ACTION_CONSOLE_ON: | |
1aaad49e FP |
1186 | if (saved_console_loglevel != -1) { |
1187 | console_loglevel = saved_console_loglevel; | |
1188 | saved_console_loglevel = -1; | |
1189 | } | |
1da177e4 | 1190 | break; |
d78ca3cd KC |
1191 | /* Set level of messages printed to console */ |
1192 | case SYSLOG_ACTION_CONSOLE_LEVEL: | |
1da177e4 LT |
1193 | error = -EINVAL; |
1194 | if (len < 1 || len > 8) | |
1195 | goto out; | |
1196 | if (len < minimum_console_loglevel) | |
1197 | len = minimum_console_loglevel; | |
1198 | console_loglevel = len; | |
1aaad49e FP |
1199 | /* Implicitly re-enable logging to console */ |
1200 | saved_console_loglevel = -1; | |
1da177e4 LT |
1201 | error = 0; |
1202 | break; | |
d78ca3cd KC |
1203 | /* Number of chars in the log buffer */ |
1204 | case SYSLOG_ACTION_SIZE_UNREAD: | |
7ff9554b KS |
1205 | raw_spin_lock_irq(&logbuf_lock); |
1206 | if (syslog_seq < log_first_seq) { | |
1207 | /* messages are gone, move to first one */ | |
1208 | syslog_seq = log_first_seq; | |
1209 | syslog_idx = log_first_idx; | |
5becfb1d | 1210 | syslog_prev = 0; |
eb02dac9 | 1211 | syslog_partial = 0; |
7ff9554b KS |
1212 | } |
1213 | if (from_file) { | |
1214 | /* | |
1215 | * Short-cut for poll(/"proc/kmsg") which simply checks | |
1216 | * for pending data, not the size; return the count of | |
1217 | * records, not the length. | |
1218 | */ | |
1219 | error = log_next_idx - syslog_idx; | |
1220 | } else { | |
5becfb1d KS |
1221 | u64 seq = syslog_seq; |
1222 | u32 idx = syslog_idx; | |
1223 | enum log_flags prev = syslog_prev; | |
7ff9554b KS |
1224 | |
1225 | error = 0; | |
7ff9554b | 1226 | while (seq < log_next_seq) { |
62e32ac3 | 1227 | struct printk_log *msg = log_from_idx(idx); |
3ce9a7c0 | 1228 | |
5becfb1d | 1229 | error += msg_print_text(msg, prev, true, NULL, 0); |
7ff9554b KS |
1230 | idx = log_next(idx); |
1231 | seq++; | |
5becfb1d | 1232 | prev = msg->flags; |
7ff9554b | 1233 | } |
eb02dac9 | 1234 | error -= syslog_partial; |
7ff9554b KS |
1235 | } |
1236 | raw_spin_unlock_irq(&logbuf_lock); | |
1da177e4 | 1237 | break; |
d78ca3cd KC |
1238 | /* Size of the log buffer */ |
1239 | case SYSLOG_ACTION_SIZE_BUFFER: | |
1da177e4 LT |
1240 | error = log_buf_len; |
1241 | break; | |
1242 | default: | |
1243 | error = -EINVAL; | |
1244 | break; | |
1245 | } | |
1246 | out: | |
1247 | return error; | |
1248 | } | |
1249 | ||
1e7bfb21 | 1250 | SYSCALL_DEFINE3(syslog, int, type, char __user *, buf, int, len) |
1da177e4 | 1251 | { |
637241a9 | 1252 | return do_syslog(type, buf, len, SYSLOG_FROM_READER); |
1da177e4 LT |
1253 | } |
1254 | ||
1da177e4 LT |
1255 | /* |
1256 | * Call the console drivers, asking them to write out | |
1257 | * log_buf[start] to log_buf[end - 1]. | |
ac751efa | 1258 | * The console_lock must be held. |
1da177e4 | 1259 | */ |
7ff9554b | 1260 | static void call_console_drivers(int level, const char *text, size_t len) |
1da177e4 | 1261 | { |
7ff9554b | 1262 | struct console *con; |
1da177e4 | 1263 | |
07c65f4d | 1264 | trace_console(text, len); |
7ff9554b KS |
1265 | |
1266 | if (level >= console_loglevel && !ignore_loglevel) | |
1267 | return; | |
1268 | if (!console_drivers) | |
1269 | return; | |
1270 | ||
1271 | for_each_console(con) { | |
1272 | if (exclusive_console && con != exclusive_console) | |
1273 | continue; | |
1274 | if (!(con->flags & CON_ENABLED)) | |
1275 | continue; | |
1276 | if (!con->write) | |
1277 | continue; | |
1278 | if (!cpu_online(smp_processor_id()) && | |
1279 | !(con->flags & CON_ANYTIME)) | |
1280 | continue; | |
1281 | con->write(con, text, len); | |
1282 | } | |
1da177e4 LT |
1283 | } |
1284 | ||
1285 | /* | |
1286 | * Zap console related locks when oopsing. Only zap at most once | |
1287 | * every 10 seconds, to leave time for slow consoles to print a | |
1288 | * full oops. | |
1289 | */ | |
1290 | static void zap_locks(void) | |
1291 | { | |
1292 | static unsigned long oops_timestamp; | |
1293 | ||
1294 | if (time_after_eq(jiffies, oops_timestamp) && | |
40dc5651 | 1295 | !time_after(jiffies, oops_timestamp + 30 * HZ)) |
1da177e4 LT |
1296 | return; |
1297 | ||
1298 | oops_timestamp = jiffies; | |
1299 | ||
94d24fc4 | 1300 | debug_locks_off(); |
1da177e4 | 1301 | /* If a crash is occurring, make sure we can't deadlock */ |
07354eb1 | 1302 | raw_spin_lock_init(&logbuf_lock); |
1da177e4 | 1303 | /* And make sure that we print immediately */ |
5b8c4f23 | 1304 | sema_init(&console_sem, 1); |
1da177e4 LT |
1305 | } |
1306 | ||
76a8ad29 ME |
1307 | /* Check if we have any console registered that can be called early in boot. */ |
1308 | static int have_callable_console(void) | |
1309 | { | |
1310 | struct console *con; | |
1311 | ||
4d091611 | 1312 | for_each_console(con) |
76a8ad29 ME |
1313 | if (con->flags & CON_ANYTIME) |
1314 | return 1; | |
1315 | ||
1316 | return 0; | |
1317 | } | |
1318 | ||
266c2e0a LT |
1319 | /* |
1320 | * Can we actually use the console at this time on this cpu? | |
1321 | * | |
1322 | * Console drivers may assume that per-cpu resources have | |
1323 | * been allocated. So unless they're explicitly marked as | |
1324 | * being able to cope (CON_ANYTIME) don't call them until | |
1325 | * this CPU is officially up. | |
1326 | */ | |
1327 | static inline int can_use_console(unsigned int cpu) | |
1328 | { | |
1329 | return cpu_online(cpu) || have_callable_console(); | |
1330 | } | |
1331 | ||
1332 | /* | |
1333 | * Try to get console ownership to actually show the kernel | |
1334 | * messages from a 'printk'. Return true (and with the | |
ac751efa | 1335 | * console_lock held, and 'console_locked' set) if it |
266c2e0a LT |
1336 | * is successful, false otherwise. |
1337 | * | |
1338 | * This gets called with the 'logbuf_lock' spinlock held and | |
1339 | * interrupts disabled. It should return with 'lockbuf_lock' | |
1340 | * released but interrupts still disabled. | |
1341 | */ | |
ac751efa | 1342 | static int console_trylock_for_printk(unsigned int cpu) |
8155c02a | 1343 | __releases(&logbuf_lock) |
266c2e0a | 1344 | { |
0b5e1c52 | 1345 | int retval = 0, wake = 0; |
266c2e0a | 1346 | |
ac751efa | 1347 | if (console_trylock()) { |
093a07e2 LT |
1348 | retval = 1; |
1349 | ||
1350 | /* | |
1351 | * If we can't use the console, we need to release | |
1352 | * the console semaphore by hand to avoid flushing | |
1353 | * the buffer. We need to hold the console semaphore | |
1354 | * in order to do this test safely. | |
1355 | */ | |
1356 | if (!can_use_console(cpu)) { | |
1357 | console_locked = 0; | |
0b5e1c52 | 1358 | wake = 1; |
093a07e2 LT |
1359 | retval = 0; |
1360 | } | |
1361 | } | |
7ff9554b | 1362 | logbuf_cpu = UINT_MAX; |
dbda92d1 | 1363 | raw_spin_unlock(&logbuf_lock); |
0b5e1c52 PZ |
1364 | if (wake) |
1365 | up(&console_sem); | |
266c2e0a LT |
1366 | return retval; |
1367 | } | |
32a76006 | 1368 | |
af91322e DY |
1369 | int printk_delay_msec __read_mostly; |
1370 | ||
1371 | static inline void printk_delay(void) | |
1372 | { | |
1373 | if (unlikely(printk_delay_msec)) { | |
1374 | int m = printk_delay_msec; | |
1375 | ||
1376 | while (m--) { | |
1377 | mdelay(1); | |
1378 | touch_nmi_watchdog(); | |
1379 | } | |
1380 | } | |
1381 | } | |
1382 | ||
084681d1 KS |
1383 | /* |
1384 | * Continuation lines are buffered, and not committed to the record buffer | |
1385 | * until the line is complete, or a race forces it. The line fragments | |
1386 | * though, are printed immediately to the consoles to ensure everything has | |
1387 | * reached the console in case of a kernel crash. | |
1388 | */ | |
1389 | static struct cont { | |
1390 | char buf[LOG_LINE_MAX]; | |
1391 | size_t len; /* length == 0 means unused buffer */ | |
1392 | size_t cons; /* bytes written to console */ | |
1393 | struct task_struct *owner; /* task of first print*/ | |
1394 | u64 ts_nsec; /* time of first print */ | |
1395 | u8 level; /* log level of first message */ | |
1396 | u8 facility; /* log level of first message */ | |
eab07260 | 1397 | enum log_flags flags; /* prefix, newline flags */ |
084681d1 KS |
1398 | bool flushed:1; /* buffer sealed and committed */ |
1399 | } cont; | |
1400 | ||
70498253 | 1401 | static void cont_flush(enum log_flags flags) |
084681d1 KS |
1402 | { |
1403 | if (cont.flushed) | |
1404 | return; | |
1405 | if (cont.len == 0) | |
1406 | return; | |
1407 | ||
eab07260 KS |
1408 | if (cont.cons) { |
1409 | /* | |
1410 | * If a fragment of this line was directly flushed to the | |
1411 | * console; wait for the console to pick up the rest of the | |
1412 | * line. LOG_NOCONS suppresses a duplicated output. | |
1413 | */ | |
1414 | log_store(cont.facility, cont.level, flags | LOG_NOCONS, | |
1415 | cont.ts_nsec, NULL, 0, cont.buf, cont.len); | |
1416 | cont.flags = flags; | |
1417 | cont.flushed = true; | |
1418 | } else { | |
1419 | /* | |
1420 | * If no fragment of this line ever reached the console, | |
1421 | * just submit it to the store and free the buffer. | |
1422 | */ | |
1423 | log_store(cont.facility, cont.level, flags, 0, | |
1424 | NULL, 0, cont.buf, cont.len); | |
1425 | cont.len = 0; | |
1426 | } | |
084681d1 KS |
1427 | } |
1428 | ||
1429 | static bool cont_add(int facility, int level, const char *text, size_t len) | |
1430 | { | |
1431 | if (cont.len && cont.flushed) | |
1432 | return false; | |
1433 | ||
1434 | if (cont.len + len > sizeof(cont.buf)) { | |
70498253 KS |
1435 | /* the line gets too long, split it up in separate records */ |
1436 | cont_flush(LOG_CONT); | |
084681d1 KS |
1437 | return false; |
1438 | } | |
1439 | ||
1440 | if (!cont.len) { | |
1441 | cont.facility = facility; | |
1442 | cont.level = level; | |
1443 | cont.owner = current; | |
1444 | cont.ts_nsec = local_clock(); | |
eab07260 | 1445 | cont.flags = 0; |
084681d1 KS |
1446 | cont.cons = 0; |
1447 | cont.flushed = false; | |
1448 | } | |
1449 | ||
1450 | memcpy(cont.buf + cont.len, text, len); | |
1451 | cont.len += len; | |
eab07260 KS |
1452 | |
1453 | if (cont.len > (sizeof(cont.buf) * 80) / 100) | |
1454 | cont_flush(LOG_CONT); | |
1455 | ||
084681d1 KS |
1456 | return true; |
1457 | } | |
1458 | ||
1459 | static size_t cont_print_text(char *text, size_t size) | |
1460 | { | |
1461 | size_t textlen = 0; | |
1462 | size_t len; | |
1463 | ||
eab07260 | 1464 | if (cont.cons == 0 && (console_prev & LOG_NEWLINE)) { |
084681d1 KS |
1465 | textlen += print_time(cont.ts_nsec, text); |
1466 | size -= textlen; | |
1467 | } | |
1468 | ||
1469 | len = cont.len - cont.cons; | |
1470 | if (len > 0) { | |
1471 | if (len+1 > size) | |
1472 | len = size-1; | |
1473 | memcpy(text + textlen, cont.buf + cont.cons, len); | |
1474 | textlen += len; | |
1475 | cont.cons = cont.len; | |
1476 | } | |
1477 | ||
1478 | if (cont.flushed) { | |
eab07260 KS |
1479 | if (cont.flags & LOG_NEWLINE) |
1480 | text[textlen++] = '\n'; | |
084681d1 KS |
1481 | /* got everything, release buffer */ |
1482 | cont.len = 0; | |
1483 | } | |
1484 | return textlen; | |
1485 | } | |
1486 | ||
7ff9554b KS |
1487 | asmlinkage int vprintk_emit(int facility, int level, |
1488 | const char *dict, size_t dictlen, | |
1489 | const char *fmt, va_list args) | |
1da177e4 | 1490 | { |
7ff9554b | 1491 | static int recursion_bug; |
7ff9554b KS |
1492 | static char textbuf[LOG_LINE_MAX]; |
1493 | char *text = textbuf; | |
c313af14 | 1494 | size_t text_len; |
5becfb1d | 1495 | enum log_flags lflags = 0; |
ac60ad74 | 1496 | unsigned long flags; |
32a76006 | 1497 | int this_cpu; |
7ff9554b | 1498 | int printed_len = 0; |
1da177e4 | 1499 | |
2fa72c8f | 1500 | boot_delay_msec(level); |
af91322e | 1501 | printk_delay(); |
bfe8df3d | 1502 | |
1da177e4 | 1503 | /* This stops the holder of console_sem just where we want him */ |
1a9a8aef | 1504 | local_irq_save(flags); |
32a76006 IM |
1505 | this_cpu = smp_processor_id(); |
1506 | ||
1507 | /* | |
1508 | * Ouch, printk recursed into itself! | |
1509 | */ | |
7ff9554b | 1510 | if (unlikely(logbuf_cpu == this_cpu)) { |
32a76006 IM |
1511 | /* |
1512 | * If a crash is occurring during printk() on this CPU, | |
1513 | * then try to get the crash message out but make sure | |
1514 | * we can't deadlock. Otherwise just return to avoid the | |
1515 | * recursion and return - but flag the recursion so that | |
1516 | * it can be printed at the next appropriate moment: | |
1517 | */ | |
94d24fc4 | 1518 | if (!oops_in_progress && !lockdep_recursing(current)) { |
3b8945e8 | 1519 | recursion_bug = 1; |
32a76006 IM |
1520 | goto out_restore_irqs; |
1521 | } | |
1522 | zap_locks(); | |
1523 | } | |
1524 | ||
a0f1ccfd | 1525 | lockdep_off(); |
07354eb1 | 1526 | raw_spin_lock(&logbuf_lock); |
7ff9554b | 1527 | logbuf_cpu = this_cpu; |
1da177e4 | 1528 | |
3b8945e8 | 1529 | if (recursion_bug) { |
7ff9554b KS |
1530 | static const char recursion_msg[] = |
1531 | "BUG: recent printk recursion!"; | |
1532 | ||
3b8945e8 | 1533 | recursion_bug = 0; |
7ff9554b KS |
1534 | printed_len += strlen(recursion_msg); |
1535 | /* emit KERN_CRIT message */ | |
5becfb1d | 1536 | log_store(0, 2, LOG_PREFIX|LOG_NEWLINE, 0, |
084681d1 | 1537 | NULL, 0, recursion_msg, printed_len); |
32a76006 | 1538 | } |
1da177e4 | 1539 | |
7ff9554b KS |
1540 | /* |
1541 | * The printf needs to come first; we need the syslog | |
1542 | * prefix which might be passed-in as a parameter. | |
1543 | */ | |
c313af14 | 1544 | text_len = vscnprintf(text, sizeof(textbuf), fmt, args); |
5fd29d6c | 1545 | |
7ff9554b | 1546 | /* mark and strip a trailing newline */ |
c313af14 KS |
1547 | if (text_len && text[text_len-1] == '\n') { |
1548 | text_len--; | |
5becfb1d | 1549 | lflags |= LOG_NEWLINE; |
7ff9554b | 1550 | } |
9d90c8d9 | 1551 | |
088a52aa JP |
1552 | /* strip kernel syslog prefix and extract log level or control flags */ |
1553 | if (facility == 0) { | |
1554 | int kern_level = printk_get_level(text); | |
1555 | ||
1556 | if (kern_level) { | |
1557 | const char *end_of_header = printk_skip_level(text); | |
1558 | switch (kern_level) { | |
1559 | case '0' ... '7': | |
1560 | if (level == -1) | |
1561 | level = kern_level - '0'; | |
1562 | case 'd': /* KERN_DEFAULT */ | |
1563 | lflags |= LOG_PREFIX; | |
1564 | case 'c': /* KERN_CONT */ | |
1565 | break; | |
1566 | } | |
1567 | text_len -= end_of_header - text; | |
1568 | text = (char *)end_of_header; | |
5fd29d6c LT |
1569 | } |
1570 | } | |
1571 | ||
c313af14 KS |
1572 | if (level == -1) |
1573 | level = default_message_loglevel; | |
9d90c8d9 | 1574 | |
5becfb1d KS |
1575 | if (dict) |
1576 | lflags |= LOG_PREFIX|LOG_NEWLINE; | |
ac60ad74 | 1577 | |
5becfb1d | 1578 | if (!(lflags & LOG_NEWLINE)) { |
084681d1 KS |
1579 | /* |
1580 | * Flush the conflicting buffer. An earlier newline was missing, | |
1581 | * or another task also prints continuation lines. | |
1582 | */ | |
5becfb1d | 1583 | if (cont.len && (lflags & LOG_PREFIX || cont.owner != current)) |
eab07260 | 1584 | cont_flush(LOG_NEWLINE); |
c313af14 | 1585 | |
084681d1 KS |
1586 | /* buffer line if possible, otherwise store it right away */ |
1587 | if (!cont_add(facility, level, text, text_len)) | |
5becfb1d | 1588 | log_store(facility, level, lflags | LOG_CONT, 0, |
084681d1 | 1589 | dict, dictlen, text, text_len); |
5c5d5ca5 | 1590 | } else { |
084681d1 | 1591 | bool stored = false; |
c313af14 | 1592 | |
084681d1 | 1593 | /* |
d3620822 SR |
1594 | * If an earlier newline was missing and it was the same task, |
1595 | * either merge it with the current buffer and flush, or if | |
1596 | * there was a race with interrupts (prefix == true) then just | |
1597 | * flush it out and store this line separately. | |
084681d1 | 1598 | */ |
084681d1 | 1599 | if (cont.len && cont.owner == current) { |
5becfb1d | 1600 | if (!(lflags & LOG_PREFIX)) |
d3620822 | 1601 | stored = cont_add(facility, level, text, text_len); |
eab07260 | 1602 | cont_flush(LOG_NEWLINE); |
c313af14 | 1603 | } |
084681d1 KS |
1604 | |
1605 | if (!stored) | |
5becfb1d | 1606 | log_store(facility, level, lflags, 0, |
084681d1 | 1607 | dict, dictlen, text, text_len); |
1da177e4 | 1608 | } |
084681d1 | 1609 | printed_len += text_len; |
1da177e4 | 1610 | |
266c2e0a | 1611 | /* |
7ff9554b KS |
1612 | * Try to acquire and then immediately release the console semaphore. |
1613 | * The release will print out buffers and wake up /dev/kmsg and syslog() | |
1614 | * users. | |
266c2e0a | 1615 | * |
7ff9554b KS |
1616 | * The console_trylock_for_printk() function will release 'logbuf_lock' |
1617 | * regardless of whether it actually gets the console semaphore or not. | |
266c2e0a | 1618 | */ |
ac751efa TH |
1619 | if (console_trylock_for_printk(this_cpu)) |
1620 | console_unlock(); | |
76a8ad29 | 1621 | |
266c2e0a | 1622 | lockdep_on(); |
32a76006 | 1623 | out_restore_irqs: |
1a9a8aef | 1624 | local_irq_restore(flags); |
76a8ad29 | 1625 | |
1da177e4 LT |
1626 | return printed_len; |
1627 | } | |
7ff9554b KS |
1628 | EXPORT_SYMBOL(vprintk_emit); |
1629 | ||
1630 | asmlinkage int vprintk(const char *fmt, va_list args) | |
1631 | { | |
1632 | return vprintk_emit(0, -1, NULL, 0, fmt, args); | |
1633 | } | |
1da177e4 LT |
1634 | EXPORT_SYMBOL(vprintk); |
1635 | ||
7ff9554b KS |
1636 | asmlinkage int printk_emit(int facility, int level, |
1637 | const char *dict, size_t dictlen, | |
1638 | const char *fmt, ...) | |
1639 | { | |
1640 | va_list args; | |
1641 | int r; | |
1642 | ||
1643 | va_start(args, fmt); | |
1644 | r = vprintk_emit(facility, level, dict, dictlen, fmt, args); | |
1645 | va_end(args); | |
1646 | ||
1647 | return r; | |
1648 | } | |
1649 | EXPORT_SYMBOL(printk_emit); | |
1650 | ||
1651 | /** | |
1652 | * printk - print a kernel message | |
1653 | * @fmt: format string | |
1654 | * | |
1655 | * This is printk(). It can be called from any context. We want it to work. | |
1656 | * | |
1657 | * We try to grab the console_lock. If we succeed, it's easy - we log the | |
1658 | * output and call the console drivers. If we fail to get the semaphore, we | |
1659 | * place the output into the log buffer and return. The current holder of | |
1660 | * the console_sem will notice the new output in console_unlock(); and will | |
1661 | * send it to the consoles before releasing the lock. | |
1662 | * | |
1663 | * One effect of this deferred printing is that code which calls printk() and | |
1664 | * then changes console_loglevel may break. This is because console_loglevel | |
1665 | * is inspected when the actual printing occurs. | |
1666 | * | |
1667 | * See also: | |
1668 | * printf(3) | |
1669 | * | |
1670 | * See the vsnprintf() documentation for format string extensions over C99. | |
1671 | */ | |
1672 | asmlinkage int printk(const char *fmt, ...) | |
1673 | { | |
1674 | va_list args; | |
1675 | int r; | |
1676 | ||
1677 | #ifdef CONFIG_KGDB_KDB | |
1678 | if (unlikely(kdb_trap_printk)) { | |
1679 | va_start(args, fmt); | |
1680 | r = vkdb_printf(fmt, args); | |
1681 | va_end(args); | |
1682 | return r; | |
1683 | } | |
1684 | #endif | |
1685 | va_start(args, fmt); | |
1686 | r = vprintk_emit(0, -1, NULL, 0, fmt, args); | |
1687 | va_end(args); | |
1688 | ||
1689 | return r; | |
1690 | } | |
1691 | EXPORT_SYMBOL(printk); | |
7f3a781d | 1692 | |
96efedf1 | 1693 | #else /* CONFIG_PRINTK */ |
d59745ce | 1694 | |
70498253 KS |
1695 | #define LOG_LINE_MAX 0 |
1696 | #define PREFIX_MAX 0 | |
7f3a781d | 1697 | #define LOG_LINE_MAX 0 |
96efedf1 KS |
1698 | static u64 syslog_seq; |
1699 | static u32 syslog_idx; | |
eab07260 KS |
1700 | static u64 console_seq; |
1701 | static u32 console_idx; | |
96efedf1 KS |
1702 | static enum log_flags syslog_prev; |
1703 | static u64 log_first_seq; | |
1704 | static u32 log_first_idx; | |
1705 | static u64 log_next_seq; | |
eab07260 | 1706 | static enum log_flags console_prev; |
084681d1 KS |
1707 | static struct cont { |
1708 | size_t len; | |
1709 | size_t cons; | |
1710 | u8 level; | |
1711 | bool flushed:1; | |
1712 | } cont; | |
62e32ac3 | 1713 | static struct printk_log *log_from_idx(u32 idx) { return NULL; } |
7f3a781d | 1714 | static u32 log_next(u32 idx) { return 0; } |
7f3a781d | 1715 | static void call_console_drivers(int level, const char *text, size_t len) {} |
62e32ac3 | 1716 | static size_t msg_print_text(const struct printk_log *msg, enum log_flags prev, |
5becfb1d | 1717 | bool syslog, char *buf, size_t size) { return 0; } |
084681d1 | 1718 | static size_t cont_print_text(char *text, size_t size) { return 0; } |
d59745ce | 1719 | |
7f3a781d | 1720 | #endif /* CONFIG_PRINTK */ |
d59745ce | 1721 | |
d0380e6c TG |
1722 | #ifdef CONFIG_EARLY_PRINTK |
1723 | struct console *early_console; | |
1724 | ||
1725 | void early_vprintk(const char *fmt, va_list ap) | |
1726 | { | |
1727 | if (early_console) { | |
1728 | char buf[512]; | |
1729 | int n = vscnprintf(buf, sizeof(buf), fmt, ap); | |
1730 | ||
1731 | early_console->write(early_console, buf, n); | |
1732 | } | |
1733 | } | |
1734 | ||
1735 | asmlinkage void early_printk(const char *fmt, ...) | |
1736 | { | |
1737 | va_list ap; | |
1738 | ||
1739 | va_start(ap, fmt); | |
1740 | early_vprintk(fmt, ap); | |
1741 | va_end(ap); | |
1742 | } | |
1743 | #endif | |
1744 | ||
f7511d5f ST |
1745 | static int __add_preferred_console(char *name, int idx, char *options, |
1746 | char *brl_options) | |
1747 | { | |
1748 | struct console_cmdline *c; | |
1749 | int i; | |
1750 | ||
1751 | /* | |
1752 | * See if this tty is not yet registered, and | |
1753 | * if we have a slot free. | |
1754 | */ | |
23475408 JP |
1755 | for (i = 0, c = console_cmdline; |
1756 | i < MAX_CMDLINECONSOLES && c->name[0]; | |
1757 | i++, c++) { | |
1758 | if (strcmp(c->name, name) == 0 && c->index == idx) { | |
1759 | if (!brl_options) | |
1760 | selected_console = i; | |
1761 | return 0; | |
f7511d5f | 1762 | } |
23475408 | 1763 | } |
f7511d5f ST |
1764 | if (i == MAX_CMDLINECONSOLES) |
1765 | return -E2BIG; | |
1766 | if (!brl_options) | |
1767 | selected_console = i; | |
f7511d5f ST |
1768 | strlcpy(c->name, name, sizeof(c->name)); |
1769 | c->options = options; | |
bbeddf52 JP |
1770 | braille_set_options(c, brl_options); |
1771 | ||
f7511d5f ST |
1772 | c->index = idx; |
1773 | return 0; | |
1774 | } | |
2ea1c539 JB |
1775 | /* |
1776 | * Set up a list of consoles. Called from init/main.c | |
1777 | */ | |
1778 | static int __init console_setup(char *str) | |
1779 | { | |
eaa944af | 1780 | char buf[sizeof(console_cmdline[0].name) + 4]; /* 4 for index */ |
f7511d5f | 1781 | char *s, *options, *brl_options = NULL; |
2ea1c539 JB |
1782 | int idx; |
1783 | ||
bbeddf52 JP |
1784 | if (_braille_console_setup(&str, &brl_options)) |
1785 | return 1; | |
f7511d5f | 1786 | |
2ea1c539 JB |
1787 | /* |
1788 | * Decode str into name, index, options. | |
1789 | */ | |
1790 | if (str[0] >= '0' && str[0] <= '9') { | |
eaa944af YL |
1791 | strcpy(buf, "ttyS"); |
1792 | strncpy(buf + 4, str, sizeof(buf) - 5); | |
2ea1c539 | 1793 | } else { |
eaa944af | 1794 | strncpy(buf, str, sizeof(buf) - 1); |
2ea1c539 | 1795 | } |
eaa944af | 1796 | buf[sizeof(buf) - 1] = 0; |
2ea1c539 JB |
1797 | if ((options = strchr(str, ',')) != NULL) |
1798 | *(options++) = 0; | |
1799 | #ifdef __sparc__ | |
1800 | if (!strcmp(str, "ttya")) | |
eaa944af | 1801 | strcpy(buf, "ttyS0"); |
2ea1c539 | 1802 | if (!strcmp(str, "ttyb")) |
eaa944af | 1803 | strcpy(buf, "ttyS1"); |
2ea1c539 | 1804 | #endif |
eaa944af | 1805 | for (s = buf; *s; s++) |
2ea1c539 JB |
1806 | if ((*s >= '0' && *s <= '9') || *s == ',') |
1807 | break; | |
1808 | idx = simple_strtoul(s, NULL, 10); | |
1809 | *s = 0; | |
1810 | ||
f7511d5f | 1811 | __add_preferred_console(buf, idx, options, brl_options); |
9e124fe1 | 1812 | console_set_on_cmdline = 1; |
2ea1c539 JB |
1813 | return 1; |
1814 | } | |
1815 | __setup("console=", console_setup); | |
1816 | ||
3c0547ba MM |
1817 | /** |
1818 | * add_preferred_console - add a device to the list of preferred consoles. | |
ddad86c2 MW |
1819 | * @name: device name |
1820 | * @idx: device index | |
1821 | * @options: options for this console | |
3c0547ba MM |
1822 | * |
1823 | * The last preferred console added will be used for kernel messages | |
1824 | * and stdin/out/err for init. Normally this is used by console_setup | |
1825 | * above to handle user-supplied console arguments; however it can also | |
1826 | * be used by arch-specific code either to override the user or more | |
1827 | * commonly to provide a default console (ie from PROM variables) when | |
1828 | * the user has not supplied one. | |
1829 | */ | |
fb445ee5 | 1830 | int add_preferred_console(char *name, int idx, char *options) |
3c0547ba | 1831 | { |
f7511d5f | 1832 | return __add_preferred_console(name, idx, options, NULL); |
3c0547ba MM |
1833 | } |
1834 | ||
b6b1d877 | 1835 | int update_console_cmdline(char *name, int idx, char *name_new, int idx_new, char *options) |
18a8bd94 YL |
1836 | { |
1837 | struct console_cmdline *c; | |
1838 | int i; | |
1839 | ||
23475408 JP |
1840 | for (i = 0, c = console_cmdline; |
1841 | i < MAX_CMDLINECONSOLES && c->name[0]; | |
1842 | i++, c++) | |
1843 | if (strcmp(c->name, name) == 0 && c->index == idx) { | |
1844 | strlcpy(c->name, name_new, sizeof(c->name)); | |
1845 | c->name[sizeof(c->name) - 1] = 0; | |
1846 | c->options = options; | |
1847 | c->index = idx_new; | |
1848 | return i; | |
18a8bd94 YL |
1849 | } |
1850 | /* not found */ | |
1851 | return -1; | |
1852 | } | |
1853 | ||
2329abfa | 1854 | bool console_suspend_enabled = 1; |
8f4ce8c3 AS |
1855 | EXPORT_SYMBOL(console_suspend_enabled); |
1856 | ||
1857 | static int __init console_suspend_disable(char *str) | |
1858 | { | |
1859 | console_suspend_enabled = 0; | |
1860 | return 1; | |
1861 | } | |
1862 | __setup("no_console_suspend", console_suspend_disable); | |
134620f7 YZ |
1863 | module_param_named(console_suspend, console_suspend_enabled, |
1864 | bool, S_IRUGO | S_IWUSR); | |
1865 | MODULE_PARM_DESC(console_suspend, "suspend console during suspend" | |
1866 | " and hibernate operations"); | |
8f4ce8c3 | 1867 | |
557240b4 LT |
1868 | /** |
1869 | * suspend_console - suspend the console subsystem | |
1870 | * | |
1871 | * This disables printk() while we go into suspend states | |
1872 | */ | |
1873 | void suspend_console(void) | |
1874 | { | |
8f4ce8c3 AS |
1875 | if (!console_suspend_enabled) |
1876 | return; | |
0d63081d | 1877 | printk("Suspending console(s) (use no_console_suspend to debug)\n"); |
ac751efa | 1878 | console_lock(); |
557240b4 | 1879 | console_suspended = 1; |
403f3075 | 1880 | up(&console_sem); |
557240b4 LT |
1881 | } |
1882 | ||
1883 | void resume_console(void) | |
1884 | { | |
8f4ce8c3 AS |
1885 | if (!console_suspend_enabled) |
1886 | return; | |
403f3075 | 1887 | down(&console_sem); |
557240b4 | 1888 | console_suspended = 0; |
ac751efa | 1889 | console_unlock(); |
557240b4 LT |
1890 | } |
1891 | ||
034260d6 KC |
1892 | /** |
1893 | * console_cpu_notify - print deferred console messages after CPU hotplug | |
1894 | * @self: notifier struct | |
1895 | * @action: CPU hotplug event | |
1896 | * @hcpu: unused | |
1897 | * | |
1898 | * If printk() is called from a CPU that is not online yet, the messages | |
1899 | * will be spooled but will not show up on the console. This function is | |
1900 | * called when a new CPU comes online (or fails to come up), and ensures | |
1901 | * that any such output gets printed. | |
1902 | */ | |
0db0628d | 1903 | static int console_cpu_notify(struct notifier_block *self, |
034260d6 KC |
1904 | unsigned long action, void *hcpu) |
1905 | { | |
1906 | switch (action) { | |
1907 | case CPU_ONLINE: | |
1908 | case CPU_DEAD: | |
034260d6 KC |
1909 | case CPU_DOWN_FAILED: |
1910 | case CPU_UP_CANCELED: | |
ac751efa TH |
1911 | console_lock(); |
1912 | console_unlock(); | |
034260d6 KC |
1913 | } |
1914 | return NOTIFY_OK; | |
1915 | } | |
1916 | ||
1da177e4 | 1917 | /** |
ac751efa | 1918 | * console_lock - lock the console system for exclusive use. |
1da177e4 | 1919 | * |
ac751efa | 1920 | * Acquires a lock which guarantees that the caller has |
1da177e4 LT |
1921 | * exclusive access to the console system and the console_drivers list. |
1922 | * | |
1923 | * Can sleep, returns nothing. | |
1924 | */ | |
ac751efa | 1925 | void console_lock(void) |
1da177e4 | 1926 | { |
6b898c07 DV |
1927 | might_sleep(); |
1928 | ||
1da177e4 | 1929 | down(&console_sem); |
403f3075 AH |
1930 | if (console_suspended) |
1931 | return; | |
1da177e4 LT |
1932 | console_locked = 1; |
1933 | console_may_schedule = 1; | |
daee7797 | 1934 | mutex_acquire(&console_lock_dep_map, 0, 0, _RET_IP_); |
1da177e4 | 1935 | } |
ac751efa | 1936 | EXPORT_SYMBOL(console_lock); |
1da177e4 | 1937 | |
ac751efa TH |
1938 | /** |
1939 | * console_trylock - try to lock the console system for exclusive use. | |
1940 | * | |
1941 | * Tried to acquire a lock which guarantees that the caller has | |
1942 | * exclusive access to the console system and the console_drivers list. | |
1943 | * | |
1944 | * returns 1 on success, and 0 on failure to acquire the lock. | |
1945 | */ | |
1946 | int console_trylock(void) | |
1da177e4 LT |
1947 | { |
1948 | if (down_trylock(&console_sem)) | |
ac751efa | 1949 | return 0; |
403f3075 AH |
1950 | if (console_suspended) { |
1951 | up(&console_sem); | |
ac751efa | 1952 | return 0; |
403f3075 | 1953 | } |
1da177e4 LT |
1954 | console_locked = 1; |
1955 | console_may_schedule = 0; | |
daee7797 | 1956 | mutex_acquire(&console_lock_dep_map, 0, 1, _RET_IP_); |
ac751efa | 1957 | return 1; |
1da177e4 | 1958 | } |
ac751efa | 1959 | EXPORT_SYMBOL(console_trylock); |
1da177e4 LT |
1960 | |
1961 | int is_console_locked(void) | |
1962 | { | |
1963 | return console_locked; | |
1964 | } | |
1da177e4 | 1965 | |
eab07260 KS |
1966 | static void console_cont_flush(char *text, size_t size) |
1967 | { | |
1968 | unsigned long flags; | |
1969 | size_t len; | |
1970 | ||
1971 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
1972 | ||
1973 | if (!cont.len) | |
1974 | goto out; | |
1975 | ||
1976 | /* | |
1977 | * We still queue earlier records, likely because the console was | |
1978 | * busy. The earlier ones need to be printed before this one, we | |
1979 | * did not flush any fragment so far, so just let it queue up. | |
1980 | */ | |
1981 | if (console_seq < log_next_seq && !cont.cons) | |
1982 | goto out; | |
1983 | ||
1984 | len = cont_print_text(text, size); | |
1985 | raw_spin_unlock(&logbuf_lock); | |
1986 | stop_critical_timings(); | |
1987 | call_console_drivers(cont.level, text, len); | |
1988 | start_critical_timings(); | |
1989 | local_irq_restore(flags); | |
1990 | return; | |
1991 | out: | |
1992 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); | |
1993 | } | |
7ff9554b | 1994 | |
1da177e4 | 1995 | /** |
ac751efa | 1996 | * console_unlock - unlock the console system |
1da177e4 | 1997 | * |
ac751efa | 1998 | * Releases the console_lock which the caller holds on the console system |
1da177e4 LT |
1999 | * and the console driver list. |
2000 | * | |
ac751efa TH |
2001 | * While the console_lock was held, console output may have been buffered |
2002 | * by printk(). If this is the case, console_unlock(); emits | |
2003 | * the output prior to releasing the lock. | |
1da177e4 | 2004 | * |
7f3a781d | 2005 | * If there is output waiting, we wake /dev/kmsg and syslog() users. |
1da177e4 | 2006 | * |
ac751efa | 2007 | * console_unlock(); may be called from any context. |
1da177e4 | 2008 | */ |
ac751efa | 2009 | void console_unlock(void) |
1da177e4 | 2010 | { |
70498253 | 2011 | static char text[LOG_LINE_MAX + PREFIX_MAX]; |
7ff9554b | 2012 | static u64 seen_seq; |
1da177e4 | 2013 | unsigned long flags; |
7ff9554b KS |
2014 | bool wake_klogd = false; |
2015 | bool retry; | |
1da177e4 | 2016 | |
557240b4 | 2017 | if (console_suspended) { |
403f3075 | 2018 | up(&console_sem); |
557240b4 LT |
2019 | return; |
2020 | } | |
78944e54 AD |
2021 | |
2022 | console_may_schedule = 0; | |
2023 | ||
084681d1 | 2024 | /* flush buffered message fragment immediately to console */ |
eab07260 | 2025 | console_cont_flush(text, sizeof(text)); |
4f2a8d3c | 2026 | again: |
7ff9554b | 2027 | for (;;) { |
62e32ac3 | 2028 | struct printk_log *msg; |
3ce9a7c0 | 2029 | size_t len; |
7ff9554b KS |
2030 | int level; |
2031 | ||
07354eb1 | 2032 | raw_spin_lock_irqsave(&logbuf_lock, flags); |
7ff9554b KS |
2033 | if (seen_seq != log_next_seq) { |
2034 | wake_klogd = true; | |
2035 | seen_seq = log_next_seq; | |
2036 | } | |
2037 | ||
2038 | if (console_seq < log_first_seq) { | |
2039 | /* messages are gone, move to first one */ | |
2040 | console_seq = log_first_seq; | |
2041 | console_idx = log_first_idx; | |
5becfb1d | 2042 | console_prev = 0; |
7ff9554b | 2043 | } |
084681d1 | 2044 | skip: |
7ff9554b KS |
2045 | if (console_seq == log_next_seq) |
2046 | break; | |
2047 | ||
2048 | msg = log_from_idx(console_idx); | |
084681d1 KS |
2049 | if (msg->flags & LOG_NOCONS) { |
2050 | /* | |
2051 | * Skip record we have buffered and already printed | |
2052 | * directly to the console when we received it. | |
2053 | */ | |
2054 | console_idx = log_next(console_idx); | |
2055 | console_seq++; | |
68b6507d KS |
2056 | /* |
2057 | * We will get here again when we register a new | |
2058 | * CON_PRINTBUFFER console. Clear the flag so we | |
2059 | * will properly dump everything later. | |
2060 | */ | |
2061 | msg->flags &= ~LOG_NOCONS; | |
eab07260 | 2062 | console_prev = msg->flags; |
084681d1 KS |
2063 | goto skip; |
2064 | } | |
649e6ee3 | 2065 | |
084681d1 | 2066 | level = msg->level; |
5becfb1d KS |
2067 | len = msg_print_text(msg, console_prev, false, |
2068 | text, sizeof(text)); | |
7ff9554b KS |
2069 | console_idx = log_next(console_idx); |
2070 | console_seq++; | |
5becfb1d | 2071 | console_prev = msg->flags; |
07354eb1 | 2072 | raw_spin_unlock(&logbuf_lock); |
7ff9554b | 2073 | |
81d68a96 | 2074 | stop_critical_timings(); /* don't trace print latency */ |
7ff9554b | 2075 | call_console_drivers(level, text, len); |
81d68a96 | 2076 | start_critical_timings(); |
1da177e4 LT |
2077 | local_irq_restore(flags); |
2078 | } | |
2079 | console_locked = 0; | |
daee7797 | 2080 | mutex_release(&console_lock_dep_map, 1, _RET_IP_); |
fe3d8ad3 FT |
2081 | |
2082 | /* Release the exclusive_console once it is used */ | |
2083 | if (unlikely(exclusive_console)) | |
2084 | exclusive_console = NULL; | |
2085 | ||
07354eb1 | 2086 | raw_spin_unlock(&logbuf_lock); |
4f2a8d3c | 2087 | |
0b5e1c52 | 2088 | up(&console_sem); |
4f2a8d3c PZ |
2089 | |
2090 | /* | |
2091 | * Someone could have filled up the buffer again, so re-check if there's | |
2092 | * something to flush. In case we cannot trylock the console_sem again, | |
2093 | * there's a new owner and the console_unlock() from them will do the | |
2094 | * flush, no worries. | |
2095 | */ | |
07354eb1 | 2096 | raw_spin_lock(&logbuf_lock); |
7ff9554b | 2097 | retry = console_seq != log_next_seq; |
09dc3cf9 PZ |
2098 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
2099 | ||
4f2a8d3c PZ |
2100 | if (retry && console_trylock()) |
2101 | goto again; | |
2102 | ||
e3e8a75d KK |
2103 | if (wake_klogd) |
2104 | wake_up_klogd(); | |
1da177e4 | 2105 | } |
ac751efa | 2106 | EXPORT_SYMBOL(console_unlock); |
1da177e4 | 2107 | |
ddad86c2 MW |
2108 | /** |
2109 | * console_conditional_schedule - yield the CPU if required | |
1da177e4 LT |
2110 | * |
2111 | * If the console code is currently allowed to sleep, and | |
2112 | * if this CPU should yield the CPU to another task, do | |
2113 | * so here. | |
2114 | * | |
ac751efa | 2115 | * Must be called within console_lock();. |
1da177e4 LT |
2116 | */ |
2117 | void __sched console_conditional_schedule(void) | |
2118 | { | |
2119 | if (console_may_schedule) | |
2120 | cond_resched(); | |
2121 | } | |
2122 | EXPORT_SYMBOL(console_conditional_schedule); | |
2123 | ||
1da177e4 LT |
2124 | void console_unblank(void) |
2125 | { | |
2126 | struct console *c; | |
2127 | ||
2128 | /* | |
2129 | * console_unblank can no longer be called in interrupt context unless | |
2130 | * oops_in_progress is set to 1.. | |
2131 | */ | |
2132 | if (oops_in_progress) { | |
2133 | if (down_trylock(&console_sem) != 0) | |
2134 | return; | |
2135 | } else | |
ac751efa | 2136 | console_lock(); |
1da177e4 LT |
2137 | |
2138 | console_locked = 1; | |
2139 | console_may_schedule = 0; | |
4d091611 | 2140 | for_each_console(c) |
1da177e4 LT |
2141 | if ((c->flags & CON_ENABLED) && c->unblank) |
2142 | c->unblank(); | |
ac751efa | 2143 | console_unlock(); |
1da177e4 | 2144 | } |
1da177e4 LT |
2145 | |
2146 | /* | |
2147 | * Return the console tty driver structure and its associated index | |
2148 | */ | |
2149 | struct tty_driver *console_device(int *index) | |
2150 | { | |
2151 | struct console *c; | |
2152 | struct tty_driver *driver = NULL; | |
2153 | ||
ac751efa | 2154 | console_lock(); |
4d091611 | 2155 | for_each_console(c) { |
1da177e4 LT |
2156 | if (!c->device) |
2157 | continue; | |
2158 | driver = c->device(c, index); | |
2159 | if (driver) | |
2160 | break; | |
2161 | } | |
ac751efa | 2162 | console_unlock(); |
1da177e4 LT |
2163 | return driver; |
2164 | } | |
2165 | ||
2166 | /* | |
2167 | * Prevent further output on the passed console device so that (for example) | |
2168 | * serial drivers can disable console output before suspending a port, and can | |
2169 | * re-enable output afterwards. | |
2170 | */ | |
2171 | void console_stop(struct console *console) | |
2172 | { | |
ac751efa | 2173 | console_lock(); |
1da177e4 | 2174 | console->flags &= ~CON_ENABLED; |
ac751efa | 2175 | console_unlock(); |
1da177e4 LT |
2176 | } |
2177 | EXPORT_SYMBOL(console_stop); | |
2178 | ||
2179 | void console_start(struct console *console) | |
2180 | { | |
ac751efa | 2181 | console_lock(); |
1da177e4 | 2182 | console->flags |= CON_ENABLED; |
ac751efa | 2183 | console_unlock(); |
1da177e4 LT |
2184 | } |
2185 | EXPORT_SYMBOL(console_start); | |
2186 | ||
7bf69395 FDN |
2187 | static int __read_mostly keep_bootcon; |
2188 | ||
2189 | static int __init keep_bootcon_setup(char *str) | |
2190 | { | |
2191 | keep_bootcon = 1; | |
27083bac | 2192 | pr_info("debug: skip boot console de-registration.\n"); |
7bf69395 FDN |
2193 | |
2194 | return 0; | |
2195 | } | |
2196 | ||
2197 | early_param("keep_bootcon", keep_bootcon_setup); | |
2198 | ||
1da177e4 LT |
2199 | /* |
2200 | * The console driver calls this routine during kernel initialization | |
2201 | * to register the console printing procedure with printk() and to | |
2202 | * print any messages that were printed by the kernel before the | |
2203 | * console driver was initialized. | |
4d091611 RG |
2204 | * |
2205 | * This can happen pretty early during the boot process (because of | |
2206 | * early_printk) - sometimes before setup_arch() completes - be careful | |
2207 | * of what kernel features are used - they may not be initialised yet. | |
2208 | * | |
2209 | * There are two types of consoles - bootconsoles (early_printk) and | |
2210 | * "real" consoles (everything which is not a bootconsole) which are | |
2211 | * handled differently. | |
2212 | * - Any number of bootconsoles can be registered at any time. | |
2213 | * - As soon as a "real" console is registered, all bootconsoles | |
2214 | * will be unregistered automatically. | |
2215 | * - Once a "real" console is registered, any attempt to register a | |
2216 | * bootconsoles will be rejected | |
1da177e4 | 2217 | */ |
4d091611 | 2218 | void register_console(struct console *newcon) |
1da177e4 | 2219 | { |
40dc5651 | 2220 | int i; |
1da177e4 | 2221 | unsigned long flags; |
4d091611 | 2222 | struct console *bcon = NULL; |
23475408 | 2223 | struct console_cmdline *c; |
1da177e4 | 2224 | |
16cf48a6 AB |
2225 | if (console_drivers) |
2226 | for_each_console(bcon) | |
2227 | if (WARN(bcon == newcon, | |
2228 | "console '%s%d' already registered\n", | |
2229 | bcon->name, bcon->index)) | |
2230 | return; | |
2231 | ||
4d091611 RG |
2232 | /* |
2233 | * before we register a new CON_BOOT console, make sure we don't | |
2234 | * already have a valid console | |
2235 | */ | |
2236 | if (console_drivers && newcon->flags & CON_BOOT) { | |
2237 | /* find the last or real console */ | |
2238 | for_each_console(bcon) { | |
2239 | if (!(bcon->flags & CON_BOOT)) { | |
27083bac | 2240 | pr_info("Too late to register bootconsole %s%d\n", |
4d091611 RG |
2241 | newcon->name, newcon->index); |
2242 | return; | |
2243 | } | |
2244 | } | |
69331af7 GH |
2245 | } |
2246 | ||
4d091611 RG |
2247 | if (console_drivers && console_drivers->flags & CON_BOOT) |
2248 | bcon = console_drivers; | |
2249 | ||
2250 | if (preferred_console < 0 || bcon || !console_drivers) | |
1da177e4 LT |
2251 | preferred_console = selected_console; |
2252 | ||
4d091611 RG |
2253 | if (newcon->early_setup) |
2254 | newcon->early_setup(); | |
18a8bd94 | 2255 | |
1da177e4 LT |
2256 | /* |
2257 | * See if we want to use this console driver. If we | |
2258 | * didn't select a console we take the first one | |
2259 | * that registers here. | |
2260 | */ | |
2261 | if (preferred_console < 0) { | |
4d091611 RG |
2262 | if (newcon->index < 0) |
2263 | newcon->index = 0; | |
2264 | if (newcon->setup == NULL || | |
2265 | newcon->setup(newcon, NULL) == 0) { | |
2266 | newcon->flags |= CON_ENABLED; | |
2267 | if (newcon->device) { | |
2268 | newcon->flags |= CON_CONSDEV; | |
cd3a1b85 JK |
2269 | preferred_console = 0; |
2270 | } | |
1da177e4 LT |
2271 | } |
2272 | } | |
2273 | ||
2274 | /* | |
2275 | * See if this console matches one we selected on | |
2276 | * the command line. | |
2277 | */ | |
23475408 JP |
2278 | for (i = 0, c = console_cmdline; |
2279 | i < MAX_CMDLINECONSOLES && c->name[0]; | |
2280 | i++, c++) { | |
2281 | if (strcmp(c->name, newcon->name) != 0) | |
1da177e4 | 2282 | continue; |
4d091611 | 2283 | if (newcon->index >= 0 && |
23475408 | 2284 | newcon->index != c->index) |
1da177e4 | 2285 | continue; |
4d091611 | 2286 | if (newcon->index < 0) |
23475408 | 2287 | newcon->index = c->index; |
bbeddf52 | 2288 | |
23475408 | 2289 | if (_braille_register_console(newcon, c)) |
f7511d5f | 2290 | return; |
bbeddf52 | 2291 | |
4d091611 RG |
2292 | if (newcon->setup && |
2293 | newcon->setup(newcon, console_cmdline[i].options) != 0) | |
1da177e4 | 2294 | break; |
4d091611 | 2295 | newcon->flags |= CON_ENABLED; |
23475408 | 2296 | newcon->index = c->index; |
ab4af03a | 2297 | if (i == selected_console) { |
4d091611 | 2298 | newcon->flags |= CON_CONSDEV; |
ab4af03a GE |
2299 | preferred_console = selected_console; |
2300 | } | |
1da177e4 LT |
2301 | break; |
2302 | } | |
2303 | ||
4d091611 | 2304 | if (!(newcon->flags & CON_ENABLED)) |
1da177e4 LT |
2305 | return; |
2306 | ||
8259cf43 RG |
2307 | /* |
2308 | * If we have a bootconsole, and are switching to a real console, | |
2309 | * don't print everything out again, since when the boot console, and | |
2310 | * the real console are the same physical device, it's annoying to | |
2311 | * see the beginning boot messages twice | |
2312 | */ | |
2313 | if (bcon && ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV)) | |
4d091611 | 2314 | newcon->flags &= ~CON_PRINTBUFFER; |
1da177e4 LT |
2315 | |
2316 | /* | |
2317 | * Put this console in the list - keep the | |
2318 | * preferred driver at the head of the list. | |
2319 | */ | |
ac751efa | 2320 | console_lock(); |
4d091611 RG |
2321 | if ((newcon->flags & CON_CONSDEV) || console_drivers == NULL) { |
2322 | newcon->next = console_drivers; | |
2323 | console_drivers = newcon; | |
2324 | if (newcon->next) | |
2325 | newcon->next->flags &= ~CON_CONSDEV; | |
1da177e4 | 2326 | } else { |
4d091611 RG |
2327 | newcon->next = console_drivers->next; |
2328 | console_drivers->next = newcon; | |
1da177e4 | 2329 | } |
4d091611 | 2330 | if (newcon->flags & CON_PRINTBUFFER) { |
1da177e4 | 2331 | /* |
ac751efa | 2332 | * console_unlock(); will print out the buffered messages |
1da177e4 LT |
2333 | * for us. |
2334 | */ | |
07354eb1 | 2335 | raw_spin_lock_irqsave(&logbuf_lock, flags); |
7ff9554b KS |
2336 | console_seq = syslog_seq; |
2337 | console_idx = syslog_idx; | |
5becfb1d | 2338 | console_prev = syslog_prev; |
07354eb1 | 2339 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
fe3d8ad3 FT |
2340 | /* |
2341 | * We're about to replay the log buffer. Only do this to the | |
2342 | * just-registered console to avoid excessive message spam to | |
2343 | * the already-registered consoles. | |
2344 | */ | |
2345 | exclusive_console = newcon; | |
1da177e4 | 2346 | } |
ac751efa | 2347 | console_unlock(); |
fbc92a34 | 2348 | console_sysfs_notify(); |
8259cf43 RG |
2349 | |
2350 | /* | |
2351 | * By unregistering the bootconsoles after we enable the real console | |
2352 | * we get the "console xxx enabled" message on all the consoles - | |
2353 | * boot consoles, real consoles, etc - this is to ensure that end | |
2354 | * users know there might be something in the kernel's log buffer that | |
2355 | * went to the bootconsole (that they do not see on the real console) | |
2356 | */ | |
27083bac | 2357 | pr_info("%sconsole [%s%d] enabled\n", |
6b802394 KC |
2358 | (newcon->flags & CON_BOOT) ? "boot" : "" , |
2359 | newcon->name, newcon->index); | |
7bf69395 FDN |
2360 | if (bcon && |
2361 | ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV) && | |
2362 | !keep_bootcon) { | |
6b802394 KC |
2363 | /* We need to iterate through all boot consoles, to make |
2364 | * sure we print everything out, before we unregister them. | |
8259cf43 | 2365 | */ |
8259cf43 RG |
2366 | for_each_console(bcon) |
2367 | if (bcon->flags & CON_BOOT) | |
2368 | unregister_console(bcon); | |
8259cf43 | 2369 | } |
1da177e4 LT |
2370 | } |
2371 | EXPORT_SYMBOL(register_console); | |
2372 | ||
40dc5651 | 2373 | int unregister_console(struct console *console) |
1da177e4 | 2374 | { |
40dc5651 | 2375 | struct console *a, *b; |
bbeddf52 | 2376 | int res; |
1da177e4 | 2377 | |
27083bac | 2378 | pr_info("%sconsole [%s%d] disabled\n", |
6b802394 KC |
2379 | (console->flags & CON_BOOT) ? "boot" : "" , |
2380 | console->name, console->index); | |
2381 | ||
bbeddf52 JP |
2382 | res = _braille_unregister_console(console); |
2383 | if (res) | |
2384 | return res; | |
f7511d5f | 2385 | |
bbeddf52 | 2386 | res = 1; |
ac751efa | 2387 | console_lock(); |
1da177e4 LT |
2388 | if (console_drivers == console) { |
2389 | console_drivers=console->next; | |
2390 | res = 0; | |
e9b15b54 | 2391 | } else if (console_drivers) { |
1da177e4 LT |
2392 | for (a=console_drivers->next, b=console_drivers ; |
2393 | a; b=a, a=b->next) { | |
2394 | if (a == console) { | |
2395 | b->next = a->next; | |
2396 | res = 0; | |
2397 | break; | |
40dc5651 | 2398 | } |
1da177e4 LT |
2399 | } |
2400 | } | |
40dc5651 | 2401 | |
69331af7 | 2402 | /* |
ab4af03a GE |
2403 | * If this isn't the last console and it has CON_CONSDEV set, we |
2404 | * need to set it on the next preferred console. | |
1da177e4 | 2405 | */ |
69331af7 | 2406 | if (console_drivers != NULL && console->flags & CON_CONSDEV) |
ab4af03a | 2407 | console_drivers->flags |= CON_CONSDEV; |
1da177e4 | 2408 | |
ac751efa | 2409 | console_unlock(); |
fbc92a34 | 2410 | console_sysfs_notify(); |
1da177e4 LT |
2411 | return res; |
2412 | } | |
2413 | EXPORT_SYMBOL(unregister_console); | |
d59745ce | 2414 | |
034260d6 | 2415 | static int __init printk_late_init(void) |
0c5564bd | 2416 | { |
4d091611 RG |
2417 | struct console *con; |
2418 | ||
2419 | for_each_console(con) { | |
4c30c6f5 | 2420 | if (!keep_bootcon && con->flags & CON_BOOT) { |
42c2c8c8 | 2421 | unregister_console(con); |
cb00e99c | 2422 | } |
0c5564bd | 2423 | } |
034260d6 | 2424 | hotcpu_notifier(console_cpu_notify, 0); |
0c5564bd RG |
2425 | return 0; |
2426 | } | |
034260d6 | 2427 | late_initcall(printk_late_init); |
0c5564bd | 2428 | |
7ef3d2fd | 2429 | #if defined CONFIG_PRINTK |
dc72c32e FW |
2430 | /* |
2431 | * Delayed printk version, for scheduler-internal messages: | |
2432 | */ | |
2433 | #define PRINTK_BUF_SIZE 512 | |
2434 | ||
2435 | #define PRINTK_PENDING_WAKEUP 0x01 | |
2436 | #define PRINTK_PENDING_SCHED 0x02 | |
2437 | ||
2438 | static DEFINE_PER_CPU(int, printk_pending); | |
2439 | static DEFINE_PER_CPU(char [PRINTK_BUF_SIZE], printk_sched_buf); | |
2440 | ||
2441 | static void wake_up_klogd_work_func(struct irq_work *irq_work) | |
2442 | { | |
2443 | int pending = __this_cpu_xchg(printk_pending, 0); | |
2444 | ||
2445 | if (pending & PRINTK_PENDING_SCHED) { | |
2446 | char *buf = __get_cpu_var(printk_sched_buf); | |
27083bac | 2447 | pr_warn("[sched_delayed] %s", buf); |
dc72c32e FW |
2448 | } |
2449 | ||
2450 | if (pending & PRINTK_PENDING_WAKEUP) | |
2451 | wake_up_interruptible(&log_wait); | |
2452 | } | |
2453 | ||
2454 | static DEFINE_PER_CPU(struct irq_work, wake_up_klogd_work) = { | |
2455 | .func = wake_up_klogd_work_func, | |
2456 | .flags = IRQ_WORK_LAZY, | |
2457 | }; | |
2458 | ||
2459 | void wake_up_klogd(void) | |
2460 | { | |
2461 | preempt_disable(); | |
2462 | if (waitqueue_active(&log_wait)) { | |
2463 | this_cpu_or(printk_pending, PRINTK_PENDING_WAKEUP); | |
2464 | irq_work_queue(&__get_cpu_var(wake_up_klogd_work)); | |
2465 | } | |
2466 | preempt_enable(); | |
2467 | } | |
717115e1 | 2468 | |
600e1458 PZ |
2469 | int printk_sched(const char *fmt, ...) |
2470 | { | |
2471 | unsigned long flags; | |
2472 | va_list args; | |
2473 | char *buf; | |
2474 | int r; | |
2475 | ||
2476 | local_irq_save(flags); | |
2477 | buf = __get_cpu_var(printk_sched_buf); | |
2478 | ||
2479 | va_start(args, fmt); | |
2480 | r = vsnprintf(buf, PRINTK_BUF_SIZE, fmt, args); | |
2481 | va_end(args); | |
2482 | ||
2483 | __this_cpu_or(printk_pending, PRINTK_PENDING_SCHED); | |
74876a98 | 2484 | irq_work_queue(&__get_cpu_var(wake_up_klogd_work)); |
600e1458 PZ |
2485 | local_irq_restore(flags); |
2486 | ||
2487 | return r; | |
2488 | } | |
2489 | ||
1da177e4 LT |
2490 | /* |
2491 | * printk rate limiting, lifted from the networking subsystem. | |
2492 | * | |
641de9d8 UKK |
2493 | * This enforces a rate limit: not more than 10 kernel messages |
2494 | * every 5s to make a denial-of-service attack impossible. | |
1da177e4 | 2495 | */ |
641de9d8 UKK |
2496 | DEFINE_RATELIMIT_STATE(printk_ratelimit_state, 5 * HZ, 10); |
2497 | ||
5c828713 | 2498 | int __printk_ratelimit(const char *func) |
1da177e4 | 2499 | { |
5c828713 | 2500 | return ___ratelimit(&printk_ratelimit_state, func); |
1da177e4 | 2501 | } |
5c828713 | 2502 | EXPORT_SYMBOL(__printk_ratelimit); |
f46c4833 AM |
2503 | |
2504 | /** | |
2505 | * printk_timed_ratelimit - caller-controlled printk ratelimiting | |
2506 | * @caller_jiffies: pointer to caller's state | |
2507 | * @interval_msecs: minimum interval between prints | |
2508 | * | |
2509 | * printk_timed_ratelimit() returns true if more than @interval_msecs | |
2510 | * milliseconds have elapsed since the last time printk_timed_ratelimit() | |
2511 | * returned true. | |
2512 | */ | |
2513 | bool printk_timed_ratelimit(unsigned long *caller_jiffies, | |
2514 | unsigned int interval_msecs) | |
2515 | { | |
f2d28a2e GK |
2516 | if (*caller_jiffies == 0 |
2517 | || !time_in_range(jiffies, *caller_jiffies, | |
2518 | *caller_jiffies | |
2519 | + msecs_to_jiffies(interval_msecs))) { | |
2520 | *caller_jiffies = jiffies; | |
f46c4833 AM |
2521 | return true; |
2522 | } | |
2523 | return false; | |
2524 | } | |
2525 | EXPORT_SYMBOL(printk_timed_ratelimit); | |
456b565c SK |
2526 | |
2527 | static DEFINE_SPINLOCK(dump_list_lock); | |
2528 | static LIST_HEAD(dump_list); | |
2529 | ||
2530 | /** | |
2531 | * kmsg_dump_register - register a kernel log dumper. | |
6485536b | 2532 | * @dumper: pointer to the kmsg_dumper structure |
456b565c SK |
2533 | * |
2534 | * Adds a kernel log dumper to the system. The dump callback in the | |
2535 | * structure will be called when the kernel oopses or panics and must be | |
2536 | * set. Returns zero on success and %-EINVAL or %-EBUSY otherwise. | |
2537 | */ | |
2538 | int kmsg_dump_register(struct kmsg_dumper *dumper) | |
2539 | { | |
2540 | unsigned long flags; | |
2541 | int err = -EBUSY; | |
2542 | ||
2543 | /* The dump callback needs to be set */ | |
2544 | if (!dumper->dump) | |
2545 | return -EINVAL; | |
2546 | ||
2547 | spin_lock_irqsave(&dump_list_lock, flags); | |
2548 | /* Don't allow registering multiple times */ | |
2549 | if (!dumper->registered) { | |
2550 | dumper->registered = 1; | |
fb842b00 | 2551 | list_add_tail_rcu(&dumper->list, &dump_list); |
456b565c SK |
2552 | err = 0; |
2553 | } | |
2554 | spin_unlock_irqrestore(&dump_list_lock, flags); | |
2555 | ||
2556 | return err; | |
2557 | } | |
2558 | EXPORT_SYMBOL_GPL(kmsg_dump_register); | |
2559 | ||
2560 | /** | |
2561 | * kmsg_dump_unregister - unregister a kmsg dumper. | |
6485536b | 2562 | * @dumper: pointer to the kmsg_dumper structure |
456b565c SK |
2563 | * |
2564 | * Removes a dump device from the system. Returns zero on success and | |
2565 | * %-EINVAL otherwise. | |
2566 | */ | |
2567 | int kmsg_dump_unregister(struct kmsg_dumper *dumper) | |
2568 | { | |
2569 | unsigned long flags; | |
2570 | int err = -EINVAL; | |
2571 | ||
2572 | spin_lock_irqsave(&dump_list_lock, flags); | |
2573 | if (dumper->registered) { | |
2574 | dumper->registered = 0; | |
fb842b00 | 2575 | list_del_rcu(&dumper->list); |
456b565c SK |
2576 | err = 0; |
2577 | } | |
2578 | spin_unlock_irqrestore(&dump_list_lock, flags); | |
fb842b00 | 2579 | synchronize_rcu(); |
456b565c SK |
2580 | |
2581 | return err; | |
2582 | } | |
2583 | EXPORT_SYMBOL_GPL(kmsg_dump_unregister); | |
2584 | ||
7ff9554b KS |
2585 | static bool always_kmsg_dump; |
2586 | module_param_named(always_kmsg_dump, always_kmsg_dump, bool, S_IRUGO | S_IWUSR); | |
2587 | ||
456b565c SK |
2588 | /** |
2589 | * kmsg_dump - dump kernel log to kernel message dumpers. | |
2590 | * @reason: the reason (oops, panic etc) for dumping | |
2591 | * | |
e2ae715d KS |
2592 | * Call each of the registered dumper's dump() callback, which can |
2593 | * retrieve the kmsg records with kmsg_dump_get_line() or | |
2594 | * kmsg_dump_get_buffer(). | |
456b565c SK |
2595 | */ |
2596 | void kmsg_dump(enum kmsg_dump_reason reason) | |
2597 | { | |
456b565c | 2598 | struct kmsg_dumper *dumper; |
456b565c SK |
2599 | unsigned long flags; |
2600 | ||
c22ab332 MG |
2601 | if ((reason > KMSG_DUMP_OOPS) && !always_kmsg_dump) |
2602 | return; | |
2603 | ||
e2ae715d KS |
2604 | rcu_read_lock(); |
2605 | list_for_each_entry_rcu(dumper, &dump_list, list) { | |
2606 | if (dumper->max_reason && reason > dumper->max_reason) | |
2607 | continue; | |
2608 | ||
2609 | /* initialize iterator with data about the stored records */ | |
2610 | dumper->active = true; | |
2611 | ||
2612 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
2613 | dumper->cur_seq = clear_seq; | |
2614 | dumper->cur_idx = clear_idx; | |
2615 | dumper->next_seq = log_next_seq; | |
2616 | dumper->next_idx = log_next_idx; | |
2617 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); | |
2618 | ||
2619 | /* invoke dumper which will iterate over records */ | |
2620 | dumper->dump(dumper, reason); | |
2621 | ||
2622 | /* reset iterator */ | |
2623 | dumper->active = false; | |
2624 | } | |
2625 | rcu_read_unlock(); | |
2626 | } | |
2627 | ||
2628 | /** | |
533827c9 | 2629 | * kmsg_dump_get_line_nolock - retrieve one kmsg log line (unlocked version) |
e2ae715d KS |
2630 | * @dumper: registered kmsg dumper |
2631 | * @syslog: include the "<4>" prefixes | |
2632 | * @line: buffer to copy the line to | |
2633 | * @size: maximum size of the buffer | |
2634 | * @len: length of line placed into buffer | |
2635 | * | |
2636 | * Start at the beginning of the kmsg buffer, with the oldest kmsg | |
2637 | * record, and copy one record into the provided buffer. | |
2638 | * | |
2639 | * Consecutive calls will return the next available record moving | |
2640 | * towards the end of the buffer with the youngest messages. | |
2641 | * | |
2642 | * A return value of FALSE indicates that there are no more records to | |
2643 | * read. | |
533827c9 AV |
2644 | * |
2645 | * The function is similar to kmsg_dump_get_line(), but grabs no locks. | |
e2ae715d | 2646 | */ |
533827c9 AV |
2647 | bool kmsg_dump_get_line_nolock(struct kmsg_dumper *dumper, bool syslog, |
2648 | char *line, size_t size, size_t *len) | |
e2ae715d | 2649 | { |
62e32ac3 | 2650 | struct printk_log *msg; |
e2ae715d KS |
2651 | size_t l = 0; |
2652 | bool ret = false; | |
2653 | ||
2654 | if (!dumper->active) | |
2655 | goto out; | |
7ff9554b | 2656 | |
e2ae715d KS |
2657 | if (dumper->cur_seq < log_first_seq) { |
2658 | /* messages are gone, move to first available one */ | |
2659 | dumper->cur_seq = log_first_seq; | |
2660 | dumper->cur_idx = log_first_idx; | |
2661 | } | |
456b565c | 2662 | |
e2ae715d | 2663 | /* last entry */ |
533827c9 | 2664 | if (dumper->cur_seq >= log_next_seq) |
e2ae715d | 2665 | goto out; |
456b565c | 2666 | |
e2ae715d | 2667 | msg = log_from_idx(dumper->cur_idx); |
5becfb1d | 2668 | l = msg_print_text(msg, 0, syslog, line, size); |
e2ae715d KS |
2669 | |
2670 | dumper->cur_idx = log_next(dumper->cur_idx); | |
2671 | dumper->cur_seq++; | |
2672 | ret = true; | |
e2ae715d KS |
2673 | out: |
2674 | if (len) | |
2675 | *len = l; | |
2676 | return ret; | |
2677 | } | |
533827c9 AV |
2678 | |
2679 | /** | |
2680 | * kmsg_dump_get_line - retrieve one kmsg log line | |
2681 | * @dumper: registered kmsg dumper | |
2682 | * @syslog: include the "<4>" prefixes | |
2683 | * @line: buffer to copy the line to | |
2684 | * @size: maximum size of the buffer | |
2685 | * @len: length of line placed into buffer | |
2686 | * | |
2687 | * Start at the beginning of the kmsg buffer, with the oldest kmsg | |
2688 | * record, and copy one record into the provided buffer. | |
2689 | * | |
2690 | * Consecutive calls will return the next available record moving | |
2691 | * towards the end of the buffer with the youngest messages. | |
2692 | * | |
2693 | * A return value of FALSE indicates that there are no more records to | |
2694 | * read. | |
2695 | */ | |
2696 | bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog, | |
2697 | char *line, size_t size, size_t *len) | |
2698 | { | |
2699 | unsigned long flags; | |
2700 | bool ret; | |
2701 | ||
2702 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
2703 | ret = kmsg_dump_get_line_nolock(dumper, syslog, line, size, len); | |
2704 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); | |
2705 | ||
2706 | return ret; | |
2707 | } | |
e2ae715d KS |
2708 | EXPORT_SYMBOL_GPL(kmsg_dump_get_line); |
2709 | ||
2710 | /** | |
2711 | * kmsg_dump_get_buffer - copy kmsg log lines | |
2712 | * @dumper: registered kmsg dumper | |
2713 | * @syslog: include the "<4>" prefixes | |
4f0f4af5 | 2714 | * @buf: buffer to copy the line to |
e2ae715d KS |
2715 | * @size: maximum size of the buffer |
2716 | * @len: length of line placed into buffer | |
2717 | * | |
2718 | * Start at the end of the kmsg buffer and fill the provided buffer | |
2719 | * with as many of the the *youngest* kmsg records that fit into it. | |
2720 | * If the buffer is large enough, all available kmsg records will be | |
2721 | * copied with a single call. | |
2722 | * | |
2723 | * Consecutive calls will fill the buffer with the next block of | |
2724 | * available older records, not including the earlier retrieved ones. | |
2725 | * | |
2726 | * A return value of FALSE indicates that there are no more records to | |
2727 | * read. | |
2728 | */ | |
2729 | bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog, | |
2730 | char *buf, size_t size, size_t *len) | |
2731 | { | |
2732 | unsigned long flags; | |
2733 | u64 seq; | |
2734 | u32 idx; | |
2735 | u64 next_seq; | |
2736 | u32 next_idx; | |
5becfb1d | 2737 | enum log_flags prev; |
e2ae715d KS |
2738 | size_t l = 0; |
2739 | bool ret = false; | |
2740 | ||
2741 | if (!dumper->active) | |
2742 | goto out; | |
2743 | ||
2744 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
2745 | if (dumper->cur_seq < log_first_seq) { | |
2746 | /* messages are gone, move to first available one */ | |
2747 | dumper->cur_seq = log_first_seq; | |
2748 | dumper->cur_idx = log_first_idx; | |
2749 | } | |
2750 | ||
2751 | /* last entry */ | |
2752 | if (dumper->cur_seq >= dumper->next_seq) { | |
2753 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); | |
2754 | goto out; | |
2755 | } | |
2756 | ||
2757 | /* calculate length of entire buffer */ | |
2758 | seq = dumper->cur_seq; | |
2759 | idx = dumper->cur_idx; | |
5becfb1d | 2760 | prev = 0; |
e2ae715d | 2761 | while (seq < dumper->next_seq) { |
62e32ac3 | 2762 | struct printk_log *msg = log_from_idx(idx); |
e2ae715d | 2763 | |
5becfb1d | 2764 | l += msg_print_text(msg, prev, true, NULL, 0); |
e2ae715d KS |
2765 | idx = log_next(idx); |
2766 | seq++; | |
5becfb1d | 2767 | prev = msg->flags; |
e2ae715d KS |
2768 | } |
2769 | ||
2770 | /* move first record forward until length fits into the buffer */ | |
2771 | seq = dumper->cur_seq; | |
2772 | idx = dumper->cur_idx; | |
5becfb1d | 2773 | prev = 0; |
e2ae715d | 2774 | while (l > size && seq < dumper->next_seq) { |
62e32ac3 | 2775 | struct printk_log *msg = log_from_idx(idx); |
456b565c | 2776 | |
5becfb1d | 2777 | l -= msg_print_text(msg, prev, true, NULL, 0); |
e2ae715d KS |
2778 | idx = log_next(idx); |
2779 | seq++; | |
5becfb1d | 2780 | prev = msg->flags; |
456b565c | 2781 | } |
e2ae715d KS |
2782 | |
2783 | /* last message in next interation */ | |
2784 | next_seq = seq; | |
2785 | next_idx = idx; | |
2786 | ||
2787 | l = 0; | |
5becfb1d | 2788 | prev = 0; |
e2ae715d | 2789 | while (seq < dumper->next_seq) { |
62e32ac3 | 2790 | struct printk_log *msg = log_from_idx(idx); |
e2ae715d | 2791 | |
5becfb1d | 2792 | l += msg_print_text(msg, prev, syslog, buf + l, size - l); |
e2ae715d KS |
2793 | idx = log_next(idx); |
2794 | seq++; | |
5becfb1d | 2795 | prev = msg->flags; |
e2ae715d KS |
2796 | } |
2797 | ||
2798 | dumper->next_seq = next_seq; | |
2799 | dumper->next_idx = next_idx; | |
2800 | ret = true; | |
7ff9554b | 2801 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
e2ae715d KS |
2802 | out: |
2803 | if (len) | |
2804 | *len = l; | |
2805 | return ret; | |
2806 | } | |
2807 | EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer); | |
456b565c | 2808 | |
533827c9 AV |
2809 | /** |
2810 | * kmsg_dump_rewind_nolock - reset the interator (unlocked version) | |
2811 | * @dumper: registered kmsg dumper | |
2812 | * | |
2813 | * Reset the dumper's iterator so that kmsg_dump_get_line() and | |
2814 | * kmsg_dump_get_buffer() can be called again and used multiple | |
2815 | * times within the same dumper.dump() callback. | |
2816 | * | |
2817 | * The function is similar to kmsg_dump_rewind(), but grabs no locks. | |
2818 | */ | |
2819 | void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper) | |
2820 | { | |
2821 | dumper->cur_seq = clear_seq; | |
2822 | dumper->cur_idx = clear_idx; | |
2823 | dumper->next_seq = log_next_seq; | |
2824 | dumper->next_idx = log_next_idx; | |
2825 | } | |
2826 | ||
e2ae715d KS |
2827 | /** |
2828 | * kmsg_dump_rewind - reset the interator | |
2829 | * @dumper: registered kmsg dumper | |
2830 | * | |
2831 | * Reset the dumper's iterator so that kmsg_dump_get_line() and | |
2832 | * kmsg_dump_get_buffer() can be called again and used multiple | |
2833 | * times within the same dumper.dump() callback. | |
2834 | */ | |
2835 | void kmsg_dump_rewind(struct kmsg_dumper *dumper) | |
2836 | { | |
2837 | unsigned long flags; | |
2838 | ||
2839 | raw_spin_lock_irqsave(&logbuf_lock, flags); | |
533827c9 | 2840 | kmsg_dump_rewind_nolock(dumper); |
e2ae715d | 2841 | raw_spin_unlock_irqrestore(&logbuf_lock, flags); |
456b565c | 2842 | } |
e2ae715d | 2843 | EXPORT_SYMBOL_GPL(kmsg_dump_rewind); |
196779b9 | 2844 | |
98e5e1bf TH |
2845 | static char dump_stack_arch_desc_str[128]; |
2846 | ||
2847 | /** | |
2848 | * dump_stack_set_arch_desc - set arch-specific str to show with task dumps | |
2849 | * @fmt: printf-style format string | |
2850 | * @...: arguments for the format string | |
2851 | * | |
2852 | * The configured string will be printed right after utsname during task | |
2853 | * dumps. Usually used to add arch-specific system identifiers. If an | |
2854 | * arch wants to make use of such an ID string, it should initialize this | |
2855 | * as soon as possible during boot. | |
2856 | */ | |
2857 | void __init dump_stack_set_arch_desc(const char *fmt, ...) | |
2858 | { | |
2859 | va_list args; | |
2860 | ||
2861 | va_start(args, fmt); | |
2862 | vsnprintf(dump_stack_arch_desc_str, sizeof(dump_stack_arch_desc_str), | |
2863 | fmt, args); | |
2864 | va_end(args); | |
2865 | } | |
2866 | ||
196779b9 TH |
2867 | /** |
2868 | * dump_stack_print_info - print generic debug info for dump_stack() | |
2869 | * @log_lvl: log level | |
2870 | * | |
2871 | * Arch-specific dump_stack() implementations can use this function to | |
2872 | * print out the same debug information as the generic dump_stack(). | |
2873 | */ | |
2874 | void dump_stack_print_info(const char *log_lvl) | |
2875 | { | |
2876 | printk("%sCPU: %d PID: %d Comm: %.20s %s %s %.*s\n", | |
2877 | log_lvl, raw_smp_processor_id(), current->pid, current->comm, | |
2878 | print_tainted(), init_utsname()->release, | |
2879 | (int)strcspn(init_utsname()->version, " "), | |
2880 | init_utsname()->version); | |
98e5e1bf TH |
2881 | |
2882 | if (dump_stack_arch_desc_str[0] != '\0') | |
2883 | printk("%sHardware name: %s\n", | |
2884 | log_lvl, dump_stack_arch_desc_str); | |
3d1cb205 TH |
2885 | |
2886 | print_worker_info(log_lvl, current); | |
196779b9 TH |
2887 | } |
2888 | ||
a43cb95d TH |
2889 | /** |
2890 | * show_regs_print_info - print generic debug info for show_regs() | |
2891 | * @log_lvl: log level | |
2892 | * | |
2893 | * show_regs() implementations can use this function to print out generic | |
2894 | * debug information. | |
2895 | */ | |
2896 | void show_regs_print_info(const char *log_lvl) | |
2897 | { | |
2898 | dump_stack_print_info(log_lvl); | |
2899 | ||
2900 | printk("%stask: %p ti: %p task.ti: %p\n", | |
2901 | log_lvl, current, current_thread_info(), | |
2902 | task_thread_info(current)); | |
2903 | } | |
2904 | ||
7ef3d2fd | 2905 | #endif |