Commit | Line | Data |
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dbddf429 | 1 | // SPDX-License-Identifier: GPL-2.0 |
cb8fa61c | 2 | /* |
e99525f9 | 3 | * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{linux.intel,addtoit}.com) |
1da177e4 LT |
4 | */ |
5 | ||
1da177e4 | 6 | #include <stdlib.h> |
e99525f9 | 7 | #include <unistd.h> |
1da177e4 | 8 | #include <errno.h> |
1d2ddcfb | 9 | #include <sched.h> |
e99525f9 JD |
10 | #include <signal.h> |
11 | #include <termios.h> | |
1da177e4 | 12 | #include <sys/ioctl.h> |
1da177e4 | 13 | #include "chan_user.h" |
37185b33 AV |
14 | #include <os.h> |
15 | #include <um_malloc.h> | |
89fe6476 JD |
16 | |
17 | void generic_close(int fd, void *unused) | |
18 | { | |
8e2d10e1 | 19 | close(fd); |
89fe6476 JD |
20 | } |
21 | ||
b49d1849 | 22 | int generic_read(int fd, __u8 *c_out, void *unused) |
89fe6476 JD |
23 | { |
24 | int n; | |
25 | ||
c6c4cbaa | 26 | CATCH_EINTR(n = read(fd, c_out, sizeof(*c_out))); |
8e2d10e1 JD |
27 | if (n > 0) |
28 | return n; | |
8e2d10e1 | 29 | else if (n == 0) |
89fe6476 | 30 | return -EIO; |
9b1c0c0e AI |
31 | else if (errno == EAGAIN) |
32 | return 0; | |
8e2d10e1 | 33 | return -errno; |
89fe6476 JD |
34 | } |
35 | ||
8e2d10e1 | 36 | /* XXX Trivial wrapper around write */ |
89fe6476 | 37 | |
b49d1849 | 38 | int generic_write(int fd, const __u8 *buf, size_t n, void *unused) |
89fe6476 | 39 | { |
4cfb44df | 40 | int written = 0; |
c59dbcad JD |
41 | int err; |
42 | ||
4cfb44df BB |
43 | /* The FD may be in blocking mode, as such, need to retry short writes, |
44 | * they may have been interrupted by a signal. | |
45 | */ | |
46 | do { | |
47 | errno = 0; | |
48 | err = write(fd, buf + written, n - written); | |
49 | if (err > 0) { | |
50 | written += err; | |
51 | continue; | |
52 | } | |
53 | } while (err < 0 && errno == EINTR); | |
54 | ||
55 | if (written > 0) | |
56 | return written; | |
c59dbcad JD |
57 | else if (errno == EAGAIN) |
58 | return 0; | |
59 | else if (err == 0) | |
60 | return -EIO; | |
61 | return -errno; | |
89fe6476 JD |
62 | } |
63 | ||
64 | int generic_window_size(int fd, void *unused, unsigned short *rows_out, | |
65 | unsigned short *cols_out) | |
66 | { | |
8e2d10e1 | 67 | struct winsize size; |
89fe6476 JD |
68 | int ret; |
69 | ||
e99525f9 | 70 | if (ioctl(fd, TIOCGWINSZ, &size) < 0) |
8e2d10e1 | 71 | return -errno; |
89fe6476 | 72 | |
8e2d10e1 | 73 | ret = ((*rows_out != size.ws_row) || (*cols_out != size.ws_col)); |
89fe6476 | 74 | |
8e2d10e1 JD |
75 | *rows_out = size.ws_row; |
76 | *cols_out = size.ws_col; | |
89fe6476 JD |
77 | |
78 | return ret; | |
79 | } | |
80 | ||
81 | void generic_free(void *data) | |
82 | { | |
83 | kfree(data); | |
84 | } | |
1da177e4 | 85 | |
55c033c1 | 86 | int generic_console_write(int fd, const char *buf, int n) |
1da177e4 | 87 | { |
ce3b642d | 88 | sigset_t old, no_sigio; |
1da177e4 LT |
89 | struct termios save, new; |
90 | int err; | |
91 | ||
e99525f9 | 92 | if (isatty(fd)) { |
ce3b642d JD |
93 | sigemptyset(&no_sigio); |
94 | sigaddset(&no_sigio, SIGIO); | |
95 | if (sigprocmask(SIG_BLOCK, &no_sigio, &old)) | |
96 | goto error; | |
97 | ||
1da177e4 LT |
98 | CATCH_EINTR(err = tcgetattr(fd, &save)); |
99 | if (err) | |
100 | goto error; | |
101 | new = save; | |
cb8fa61c JD |
102 | /* |
103 | * The terminal becomes a bit less raw, to handle \n also as | |
1da177e4 | 104 | * "Carriage Return", not only as "New Line". Otherwise, the new |
cb8fa61c JD |
105 | * line won't start at the first column. |
106 | */ | |
1da177e4 LT |
107 | new.c_oflag |= OPOST; |
108 | CATCH_EINTR(err = tcsetattr(fd, TCSAFLUSH, &new)); | |
109 | if (err) | |
110 | goto error; | |
111 | } | |
112 | err = generic_write(fd, buf, n, NULL); | |
cb8fa61c JD |
113 | /* |
114 | * Restore raw mode, in any case; we *must* ignore any error apart | |
115 | * EINTR, except for debug. | |
116 | */ | |
ce3b642d | 117 | if (isatty(fd)) { |
1da177e4 | 118 | CATCH_EINTR(tcsetattr(fd, TCSAFLUSH, &save)); |
ce3b642d JD |
119 | sigprocmask(SIG_SETMASK, &old, NULL); |
120 | } | |
121 | ||
e99525f9 | 122 | return err; |
1da177e4 | 123 | error: |
e99525f9 | 124 | return -errno; |
1da177e4 LT |
125 | } |
126 | ||
127 | /* | |
128 | * UML SIGWINCH handling | |
129 | * | |
42a359e3 JD |
130 | * The point of this is to handle SIGWINCH on consoles which have host |
131 | * ttys and relay them inside UML to whatever might be running on the | |
132 | * console and cares about the window size (since SIGWINCH notifies | |
133 | * about terminal size changes). | |
1da177e4 | 134 | * |
42a359e3 JD |
135 | * So, we have a separate thread for each host tty attached to a UML |
136 | * device (side-issue - I'm annoyed that one thread can't have | |
137 | * multiple controlling ttys for the purpose of handling SIGWINCH, but | |
138 | * I imagine there are other reasons that doesn't make any sense). | |
1da177e4 | 139 | * |
42a359e3 JD |
140 | * SIGWINCH can't be received synchronously, so you have to set up to |
141 | * receive it as a signal. That being the case, if you are going to | |
142 | * wait for it, it is convenient to sit in sigsuspend() and wait for | |
143 | * the signal to bounce you out of it (see below for how we make sure | |
144 | * to exit only on SIGWINCH). | |
1da177e4 LT |
145 | */ |
146 | ||
147 | static void winch_handler(int sig) | |
148 | { | |
149 | } | |
150 | ||
151 | struct winch_data { | |
152 | int pty_fd; | |
153 | int pipe_fd; | |
1da177e4 LT |
154 | }; |
155 | ||
139e6e8e | 156 | static __noreturn int winch_thread(void *arg) |
1da177e4 LT |
157 | { |
158 | struct winch_data *data = arg; | |
159 | sigset_t sigs; | |
160 | int pty_fd, pipe_fd; | |
8ca842c4 | 161 | int count; |
1da177e4 LT |
162 | char c = 1; |
163 | ||
1da177e4 LT |
164 | pty_fd = data->pty_fd; |
165 | pipe_fd = data->pipe_fd; | |
8ca842c4 | 166 | count = write(pipe_fd, &c, sizeof(c)); |
e99525f9 | 167 | if (count != sizeof(c)) |
1818b840 BB |
168 | os_info("winch_thread : failed to write synchronization byte, err = %d\n", |
169 | -count); | |
1da177e4 | 170 | |
e99525f9 JD |
171 | /* |
172 | * We are not using SIG_IGN on purpose, so don't fix it as I thought to | |
ed1b58d8 | 173 | * do! If using SIG_IGN, the sigsuspend() call below would not stop on |
e99525f9 JD |
174 | * SIGWINCH. |
175 | */ | |
1da177e4 LT |
176 | |
177 | signal(SIGWINCH, winch_handler); | |
178 | sigfillset(&sigs); | |
ed1b58d8 | 179 | /* Block all signals possible. */ |
e99525f9 | 180 | if (sigprocmask(SIG_SETMASK, &sigs, NULL) < 0) { |
1818b840 BB |
181 | os_info("winch_thread : sigprocmask failed, errno = %d\n", |
182 | errno); | |
139e6e8e | 183 | goto wait_kill; |
1da177e4 | 184 | } |
ed1b58d8 BS |
185 | /* In sigsuspend(), block anything else than SIGWINCH. */ |
186 | sigdelset(&sigs, SIGWINCH); | |
1da177e4 | 187 | |
e99525f9 | 188 | if (setsid() < 0) { |
1818b840 | 189 | os_info("winch_thread : setsid failed, errno = %d\n", |
e99525f9 | 190 | errno); |
139e6e8e | 191 | goto wait_kill; |
1da177e4 LT |
192 | } |
193 | ||
cb8fa61c | 194 | if (ioctl(pty_fd, TIOCSCTTY, 0) < 0) { |
1818b840 BB |
195 | os_info("winch_thread : TIOCSCTTY failed on " |
196 | "fd %d err = %d\n", pty_fd, errno); | |
139e6e8e | 197 | goto wait_kill; |
8ca842c4 JD |
198 | } |
199 | ||
cb8fa61c | 200 | if (tcsetpgrp(pty_fd, os_getpid()) < 0) { |
1818b840 BB |
201 | os_info("winch_thread : tcsetpgrp failed on fd %d err = %d\n", |
202 | pty_fd, errno); | |
139e6e8e | 203 | goto wait_kill; |
1da177e4 LT |
204 | } |
205 | ||
e99525f9 JD |
206 | /* |
207 | * These are synchronization calls between various UML threads on the | |
1da177e4 LT |
208 | * host - since they are not different kernel threads, we cannot use |
209 | * kernel semaphores. We don't use SysV semaphores because they are | |
e99525f9 JD |
210 | * persistent. |
211 | */ | |
8ca842c4 | 212 | count = read(pipe_fd, &c, sizeof(c)); |
e99525f9 | 213 | if (count != sizeof(c)) |
1818b840 BB |
214 | os_info("winch_thread : failed to read synchronization byte, err = %d\n", |
215 | errno); | |
1da177e4 | 216 | |
e99525f9 JD |
217 | while(1) { |
218 | /* | |
219 | * This will be interrupted by SIGWINCH only, since | |
42a359e3 JD |
220 | * other signals are blocked. |
221 | */ | |
ed1b58d8 | 222 | sigsuspend(&sigs); |
1da177e4 | 223 | |
8ca842c4 | 224 | count = write(pipe_fd, &c, sizeof(c)); |
e99525f9 | 225 | if (count != sizeof(c)) |
1818b840 BB |
226 | os_info("winch_thread : write failed, err = %d\n", |
227 | errno); | |
1da177e4 | 228 | } |
139e6e8e BB |
229 | |
230 | wait_kill: | |
231 | c = 2; | |
232 | count = write(pipe_fd, &c, sizeof(c)); | |
233 | while (1) | |
234 | pause(); | |
1da177e4 LT |
235 | } |
236 | ||
2116bda6 | 237 | static int winch_tramp(int fd, struct tty_port *port, int *fd_out, |
42a359e3 | 238 | unsigned long *stack_out) |
1da177e4 LT |
239 | { |
240 | struct winch_data data; | |
57ae0b67 | 241 | int fds[2], n, err, pid; |
1da177e4 LT |
242 | char c; |
243 | ||
244 | err = os_pipe(fds, 1, 1); | |
e99525f9 JD |
245 | if (err < 0) { |
246 | printk(UM_KERN_ERR "winch_tramp : os_pipe failed, err = %d\n", | |
247 | -err); | |
1f96ddb4 | 248 | goto out; |
1da177e4 LT |
249 | } |
250 | ||
251 | data = ((struct winch_data) { .pty_fd = fd, | |
1d2ddcfb | 252 | .pipe_fd = fds[1] } ); |
e99525f9 JD |
253 | /* |
254 | * CLONE_FILES so this thread doesn't hold open files which are open | |
42a359e3 JD |
255 | * now, but later closed in a different thread. This is a |
256 | * problem with /dev/net/tun, which if held open by this | |
257 | * thread, prevents the TUN/TAP device from being reused. | |
1d2ddcfb | 258 | */ |
57ae0b67 JB |
259 | pid = run_helper_thread(winch_thread, &data, CLONE_FILES, stack_out); |
260 | if (pid < 0) { | |
261 | err = pid; | |
e99525f9 JD |
262 | printk(UM_KERN_ERR "fork of winch_thread failed - errno = %d\n", |
263 | -err); | |
1f96ddb4 | 264 | goto out_close; |
1da177e4 LT |
265 | } |
266 | ||
1da177e4 | 267 | *fd_out = fds[0]; |
8ca842c4 | 268 | n = read(fds[0], &c, sizeof(c)); |
e99525f9 JD |
269 | if (n != sizeof(c)) { |
270 | printk(UM_KERN_ERR "winch_tramp : failed to read " | |
271 | "synchronization byte\n"); | |
8ca842c4 | 272 | printk(UM_KERN_ERR "read failed, err = %d\n", errno); |
e99525f9 JD |
273 | printk(UM_KERN_ERR "fd %d will not support SIGWINCH\n", fd); |
274 | err = -EINVAL; | |
1d2ddcfb | 275 | goto out_close; |
1da177e4 | 276 | } |
89df6bfc | 277 | |
ccf1236e ZL |
278 | err = os_set_fd_block(*fd_out, 0); |
279 | if (err) { | |
e99525f9 JD |
280 | printk(UM_KERN_ERR "winch_tramp: failed to set thread_fd " |
281 | "non-blocking.\n"); | |
89df6bfc EGM |
282 | goto out_close; |
283 | } | |
284 | ||
57ae0b67 | 285 | return pid; |
1f96ddb4 JD |
286 | |
287 | out_close: | |
8ca842c4 JD |
288 | close(fds[1]); |
289 | close(fds[0]); | |
1f96ddb4 JD |
290 | out: |
291 | return err; | |
1da177e4 LT |
292 | } |
293 | ||
2116bda6 | 294 | void register_winch(int fd, struct tty_port *port) |
1da177e4 | 295 | { |
42a359e3 JD |
296 | unsigned long stack; |
297 | int pid, thread, count, thread_fd = -1; | |
1da177e4 LT |
298 | char c = 1; |
299 | ||
e99525f9 | 300 | if (!isatty(fd)) |
1da177e4 LT |
301 | return; |
302 | ||
303 | pid = tcgetpgrp(fd); | |
2116bda6 RW |
304 | if (is_skas_winch(pid, fd, port)) { |
305 | register_winch_irq(-1, fd, -1, port, 0); | |
17e05209 AV |
306 | return; |
307 | } | |
308 | ||
309 | if (pid == -1) { | |
2116bda6 | 310 | thread = winch_tramp(fd, port, &thread_fd, &stack); |
42a359e3 JD |
311 | if (thread < 0) |
312 | return; | |
313 | ||
2116bda6 | 314 | register_winch_irq(thread_fd, fd, thread, port, stack); |
42a359e3 | 315 | |
8ca842c4 | 316 | count = write(thread_fd, &c, sizeof(c)); |
e99525f9 JD |
317 | if (count != sizeof(c)) |
318 | printk(UM_KERN_ERR "register_winch : failed to write " | |
8ca842c4 | 319 | "synchronization byte, err = %d\n", errno); |
1da177e4 LT |
320 | } |
321 | } |