Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * linux/fs/fcntl.c | |
3 | * | |
4 | * Copyright (C) 1991, 1992 Linus Torvalds | |
5 | */ | |
6 | ||
7 | #include <linux/syscalls.h> | |
8 | #include <linux/init.h> | |
9 | #include <linux/mm.h> | |
10 | #include <linux/fs.h> | |
11 | #include <linux/file.h> | |
16f7e0fe | 12 | #include <linux/capability.h> |
1da177e4 LT |
13 | #include <linux/dnotify.h> |
14 | #include <linux/smp_lock.h> | |
15 | #include <linux/slab.h> | |
16 | #include <linux/module.h> | |
17 | #include <linux/security.h> | |
18 | #include <linux/ptrace.h> | |
7ed20e1a | 19 | #include <linux/signal.h> |
ab2af1f5 | 20 | #include <linux/rcupdate.h> |
1da177e4 LT |
21 | |
22 | #include <asm/poll.h> | |
23 | #include <asm/siginfo.h> | |
24 | #include <asm/uaccess.h> | |
25 | ||
26 | void fastcall set_close_on_exec(unsigned int fd, int flag) | |
27 | { | |
28 | struct files_struct *files = current->files; | |
badf1662 | 29 | struct fdtable *fdt; |
1da177e4 | 30 | spin_lock(&files->file_lock); |
badf1662 | 31 | fdt = files_fdtable(files); |
1da177e4 | 32 | if (flag) |
badf1662 | 33 | FD_SET(fd, fdt->close_on_exec); |
1da177e4 | 34 | else |
badf1662 | 35 | FD_CLR(fd, fdt->close_on_exec); |
1da177e4 LT |
36 | spin_unlock(&files->file_lock); |
37 | } | |
38 | ||
858119e1 | 39 | static int get_close_on_exec(unsigned int fd) |
1da177e4 LT |
40 | { |
41 | struct files_struct *files = current->files; | |
badf1662 | 42 | struct fdtable *fdt; |
1da177e4 | 43 | int res; |
b835996f | 44 | rcu_read_lock(); |
badf1662 DS |
45 | fdt = files_fdtable(files); |
46 | res = FD_ISSET(fd, fdt->close_on_exec); | |
b835996f | 47 | rcu_read_unlock(); |
1da177e4 LT |
48 | return res; |
49 | } | |
50 | ||
51 | /* | |
52 | * locate_fd finds a free file descriptor in the open_fds fdset, | |
53 | * expanding the fd arrays if necessary. Must be called with the | |
54 | * file_lock held for write. | |
55 | */ | |
56 | ||
57 | static int locate_fd(struct files_struct *files, | |
58 | struct file *file, unsigned int orig_start) | |
59 | { | |
60 | unsigned int newfd; | |
61 | unsigned int start; | |
62 | int error; | |
badf1662 | 63 | struct fdtable *fdt; |
1da177e4 LT |
64 | |
65 | error = -EINVAL; | |
66 | if (orig_start >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur) | |
67 | goto out; | |
68 | ||
69 | repeat: | |
ab2af1f5 | 70 | fdt = files_fdtable(files); |
1da177e4 LT |
71 | /* |
72 | * Someone might have closed fd's in the range | |
badf1662 | 73 | * orig_start..fdt->next_fd |
1da177e4 LT |
74 | */ |
75 | start = orig_start; | |
0c9e63fd ED |
76 | if (start < files->next_fd) |
77 | start = files->next_fd; | |
1da177e4 LT |
78 | |
79 | newfd = start; | |
bbea9f69 | 80 | if (start < fdt->max_fds) |
badf1662 | 81 | newfd = find_next_zero_bit(fdt->open_fds->fds_bits, |
bbea9f69 | 82 | fdt->max_fds, start); |
1da177e4 LT |
83 | |
84 | error = -EMFILE; | |
85 | if (newfd >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur) | |
86 | goto out; | |
87 | ||
88 | error = expand_files(files, newfd); | |
89 | if (error < 0) | |
90 | goto out; | |
91 | ||
92 | /* | |
93 | * If we needed to expand the fs array we | |
94 | * might have blocked - try again. | |
95 | */ | |
96 | if (error) | |
97 | goto repeat; | |
98 | ||
ab2af1f5 DS |
99 | /* |
100 | * We reacquired files_lock, so we are safe as long as | |
101 | * we reacquire the fdtable pointer and use it while holding | |
102 | * the lock, no one can free it during that time. | |
103 | */ | |
0c9e63fd ED |
104 | if (start <= files->next_fd) |
105 | files->next_fd = newfd + 1; | |
ab2af1f5 | 106 | |
1da177e4 LT |
107 | error = newfd; |
108 | ||
109 | out: | |
110 | return error; | |
111 | } | |
112 | ||
22d2b35b | 113 | static int dupfd(struct file *file, unsigned int start, int cloexec) |
1da177e4 LT |
114 | { |
115 | struct files_struct * files = current->files; | |
badf1662 | 116 | struct fdtable *fdt; |
1da177e4 LT |
117 | int fd; |
118 | ||
119 | spin_lock(&files->file_lock); | |
120 | fd = locate_fd(files, file, start); | |
121 | if (fd >= 0) { | |
badf1662 DS |
122 | /* locate_fd() may have expanded fdtable, load the ptr */ |
123 | fdt = files_fdtable(files); | |
124 | FD_SET(fd, fdt->open_fds); | |
22d2b35b UD |
125 | if (cloexec) |
126 | FD_SET(fd, fdt->close_on_exec); | |
127 | else | |
128 | FD_CLR(fd, fdt->close_on_exec); | |
1da177e4 LT |
129 | spin_unlock(&files->file_lock); |
130 | fd_install(fd, file); | |
131 | } else { | |
132 | spin_unlock(&files->file_lock); | |
133 | fput(file); | |
134 | } | |
135 | ||
136 | return fd; | |
137 | } | |
138 | ||
139 | asmlinkage long sys_dup2(unsigned int oldfd, unsigned int newfd) | |
140 | { | |
141 | int err = -EBADF; | |
142 | struct file * file, *tofree; | |
143 | struct files_struct * files = current->files; | |
badf1662 | 144 | struct fdtable *fdt; |
1da177e4 LT |
145 | |
146 | spin_lock(&files->file_lock); | |
147 | if (!(file = fcheck(oldfd))) | |
148 | goto out_unlock; | |
149 | err = newfd; | |
150 | if (newfd == oldfd) | |
151 | goto out_unlock; | |
152 | err = -EBADF; | |
153 | if (newfd >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur) | |
154 | goto out_unlock; | |
155 | get_file(file); /* We are now finished with oldfd */ | |
156 | ||
157 | err = expand_files(files, newfd); | |
158 | if (err < 0) | |
159 | goto out_fput; | |
160 | ||
161 | /* To avoid races with open() and dup(), we will mark the fd as | |
162 | * in-use in the open-file bitmap throughout the entire dup2() | |
163 | * process. This is quite safe: do_close() uses the fd array | |
164 | * entry, not the bitmap, to decide what work needs to be | |
165 | * done. --sct */ | |
166 | /* Doesn't work. open() might be there first. --AV */ | |
167 | ||
168 | /* Yes. It's a race. In user space. Nothing sane to do */ | |
169 | err = -EBUSY; | |
badf1662 DS |
170 | fdt = files_fdtable(files); |
171 | tofree = fdt->fd[newfd]; | |
172 | if (!tofree && FD_ISSET(newfd, fdt->open_fds)) | |
1da177e4 LT |
173 | goto out_fput; |
174 | ||
ab2af1f5 | 175 | rcu_assign_pointer(fdt->fd[newfd], file); |
badf1662 DS |
176 | FD_SET(newfd, fdt->open_fds); |
177 | FD_CLR(newfd, fdt->close_on_exec); | |
1da177e4 LT |
178 | spin_unlock(&files->file_lock); |
179 | ||
180 | if (tofree) | |
181 | filp_close(tofree, files); | |
182 | err = newfd; | |
183 | out: | |
184 | return err; | |
185 | out_unlock: | |
186 | spin_unlock(&files->file_lock); | |
187 | goto out; | |
188 | ||
189 | out_fput: | |
190 | spin_unlock(&files->file_lock); | |
191 | fput(file); | |
192 | goto out; | |
193 | } | |
194 | ||
195 | asmlinkage long sys_dup(unsigned int fildes) | |
196 | { | |
197 | int ret = -EBADF; | |
198 | struct file * file = fget(fildes); | |
199 | ||
200 | if (file) | |
22d2b35b | 201 | ret = dupfd(file, 0, 0); |
1da177e4 LT |
202 | return ret; |
203 | } | |
204 | ||
205 | #define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | FASYNC | O_DIRECT | O_NOATIME) | |
206 | ||
207 | static int setfl(int fd, struct file * filp, unsigned long arg) | |
208 | { | |
0f7fc9e4 | 209 | struct inode * inode = filp->f_path.dentry->d_inode; |
1da177e4 LT |
210 | int error = 0; |
211 | ||
7d95c8f2 | 212 | /* |
213 | * O_APPEND cannot be cleared if the file is marked as append-only | |
214 | * and the file is open for write. | |
215 | */ | |
216 | if (((arg ^ filp->f_flags) & O_APPEND) && IS_APPEND(inode)) | |
1da177e4 LT |
217 | return -EPERM; |
218 | ||
219 | /* O_NOATIME can only be set by the owner or superuser */ | |
220 | if ((arg & O_NOATIME) && !(filp->f_flags & O_NOATIME)) | |
3bd858ab | 221 | if (!is_owner_or_cap(inode)) |
1da177e4 LT |
222 | return -EPERM; |
223 | ||
224 | /* required for strict SunOS emulation */ | |
225 | if (O_NONBLOCK != O_NDELAY) | |
226 | if (arg & O_NDELAY) | |
227 | arg |= O_NONBLOCK; | |
228 | ||
229 | if (arg & O_DIRECT) { | |
230 | if (!filp->f_mapping || !filp->f_mapping->a_ops || | |
231 | !filp->f_mapping->a_ops->direct_IO) | |
232 | return -EINVAL; | |
233 | } | |
234 | ||
235 | if (filp->f_op && filp->f_op->check_flags) | |
236 | error = filp->f_op->check_flags(arg); | |
237 | if (error) | |
238 | return error; | |
239 | ||
240 | lock_kernel(); | |
241 | if ((arg ^ filp->f_flags) & FASYNC) { | |
242 | if (filp->f_op && filp->f_op->fasync) { | |
243 | error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0); | |
244 | if (error < 0) | |
245 | goto out; | |
246 | } | |
247 | } | |
248 | ||
249 | filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK); | |
250 | out: | |
251 | unlock_kernel(); | |
252 | return error; | |
253 | } | |
254 | ||
609d7fa9 | 255 | static void f_modown(struct file *filp, struct pid *pid, enum pid_type type, |
1da177e4 LT |
256 | uid_t uid, uid_t euid, int force) |
257 | { | |
258 | write_lock_irq(&filp->f_owner.lock); | |
259 | if (force || !filp->f_owner.pid) { | |
609d7fa9 EB |
260 | put_pid(filp->f_owner.pid); |
261 | filp->f_owner.pid = get_pid(pid); | |
262 | filp->f_owner.pid_type = type; | |
1da177e4 LT |
263 | filp->f_owner.uid = uid; |
264 | filp->f_owner.euid = euid; | |
265 | } | |
266 | write_unlock_irq(&filp->f_owner.lock); | |
267 | } | |
268 | ||
609d7fa9 EB |
269 | int __f_setown(struct file *filp, struct pid *pid, enum pid_type type, |
270 | int force) | |
1da177e4 LT |
271 | { |
272 | int err; | |
273 | ||
274 | err = security_file_set_fowner(filp); | |
275 | if (err) | |
276 | return err; | |
277 | ||
609d7fa9 | 278 | f_modown(filp, pid, type, current->uid, current->euid, force); |
1da177e4 LT |
279 | return 0; |
280 | } | |
609d7fa9 | 281 | EXPORT_SYMBOL(__f_setown); |
1da177e4 | 282 | |
609d7fa9 EB |
283 | int f_setown(struct file *filp, unsigned long arg, int force) |
284 | { | |
285 | enum pid_type type; | |
286 | struct pid *pid; | |
287 | int who = arg; | |
288 | int result; | |
289 | type = PIDTYPE_PID; | |
290 | if (who < 0) { | |
291 | type = PIDTYPE_PGID; | |
292 | who = -who; | |
293 | } | |
294 | rcu_read_lock(); | |
295 | pid = find_pid(who); | |
296 | result = __f_setown(filp, pid, type, force); | |
297 | rcu_read_unlock(); | |
298 | return result; | |
299 | } | |
1da177e4 LT |
300 | EXPORT_SYMBOL(f_setown); |
301 | ||
302 | void f_delown(struct file *filp) | |
303 | { | |
609d7fa9 EB |
304 | f_modown(filp, NULL, PIDTYPE_PID, 0, 0, 1); |
305 | } | |
306 | ||
307 | pid_t f_getown(struct file *filp) | |
308 | { | |
309 | pid_t pid; | |
43fa1adb | 310 | read_lock(&filp->f_owner.lock); |
609d7fa9 EB |
311 | pid = pid_nr(filp->f_owner.pid); |
312 | if (filp->f_owner.pid_type == PIDTYPE_PGID) | |
313 | pid = -pid; | |
43fa1adb | 314 | read_unlock(&filp->f_owner.lock); |
609d7fa9 | 315 | return pid; |
1da177e4 LT |
316 | } |
317 | ||
318 | static long do_fcntl(int fd, unsigned int cmd, unsigned long arg, | |
319 | struct file *filp) | |
320 | { | |
321 | long err = -EINVAL; | |
322 | ||
323 | switch (cmd) { | |
324 | case F_DUPFD: | |
22d2b35b | 325 | case F_DUPFD_CLOEXEC: |
1da177e4 | 326 | get_file(filp); |
22d2b35b | 327 | err = dupfd(filp, arg, cmd == F_DUPFD_CLOEXEC); |
1da177e4 LT |
328 | break; |
329 | case F_GETFD: | |
330 | err = get_close_on_exec(fd) ? FD_CLOEXEC : 0; | |
331 | break; | |
332 | case F_SETFD: | |
333 | err = 0; | |
334 | set_close_on_exec(fd, arg & FD_CLOEXEC); | |
335 | break; | |
336 | case F_GETFL: | |
337 | err = filp->f_flags; | |
338 | break; | |
339 | case F_SETFL: | |
340 | err = setfl(fd, filp, arg); | |
341 | break; | |
342 | case F_GETLK: | |
343 | err = fcntl_getlk(filp, (struct flock __user *) arg); | |
344 | break; | |
345 | case F_SETLK: | |
346 | case F_SETLKW: | |
c293621b | 347 | err = fcntl_setlk(fd, filp, cmd, (struct flock __user *) arg); |
1da177e4 LT |
348 | break; |
349 | case F_GETOWN: | |
350 | /* | |
351 | * XXX If f_owner is a process group, the | |
352 | * negative return value will get converted | |
353 | * into an error. Oops. If we keep the | |
354 | * current syscall conventions, the only way | |
355 | * to fix this will be in libc. | |
356 | */ | |
609d7fa9 | 357 | err = f_getown(filp); |
1da177e4 LT |
358 | force_successful_syscall_return(); |
359 | break; | |
360 | case F_SETOWN: | |
361 | err = f_setown(filp, arg, 1); | |
362 | break; | |
363 | case F_GETSIG: | |
364 | err = filp->f_owner.signum; | |
365 | break; | |
366 | case F_SETSIG: | |
367 | /* arg == 0 restores default behaviour. */ | |
7ed20e1a | 368 | if (!valid_signal(arg)) { |
1da177e4 LT |
369 | break; |
370 | } | |
371 | err = 0; | |
372 | filp->f_owner.signum = arg; | |
373 | break; | |
374 | case F_GETLEASE: | |
375 | err = fcntl_getlease(filp); | |
376 | break; | |
377 | case F_SETLEASE: | |
378 | err = fcntl_setlease(fd, filp, arg); | |
379 | break; | |
380 | case F_NOTIFY: | |
381 | err = fcntl_dirnotify(fd, filp, arg); | |
382 | break; | |
383 | default: | |
384 | break; | |
385 | } | |
386 | return err; | |
387 | } | |
388 | ||
389 | asmlinkage long sys_fcntl(unsigned int fd, unsigned int cmd, unsigned long arg) | |
390 | { | |
391 | struct file *filp; | |
392 | long err = -EBADF; | |
393 | ||
394 | filp = fget(fd); | |
395 | if (!filp) | |
396 | goto out; | |
397 | ||
398 | err = security_file_fcntl(filp, cmd, arg); | |
399 | if (err) { | |
400 | fput(filp); | |
401 | return err; | |
402 | } | |
403 | ||
404 | err = do_fcntl(fd, cmd, arg, filp); | |
405 | ||
406 | fput(filp); | |
407 | out: | |
408 | return err; | |
409 | } | |
410 | ||
411 | #if BITS_PER_LONG == 32 | |
412 | asmlinkage long sys_fcntl64(unsigned int fd, unsigned int cmd, unsigned long arg) | |
413 | { | |
414 | struct file * filp; | |
415 | long err; | |
416 | ||
417 | err = -EBADF; | |
418 | filp = fget(fd); | |
419 | if (!filp) | |
420 | goto out; | |
421 | ||
422 | err = security_file_fcntl(filp, cmd, arg); | |
423 | if (err) { | |
424 | fput(filp); | |
425 | return err; | |
426 | } | |
427 | err = -EBADF; | |
428 | ||
429 | switch (cmd) { | |
430 | case F_GETLK64: | |
431 | err = fcntl_getlk64(filp, (struct flock64 __user *) arg); | |
432 | break; | |
433 | case F_SETLK64: | |
434 | case F_SETLKW64: | |
c293621b PS |
435 | err = fcntl_setlk64(fd, filp, cmd, |
436 | (struct flock64 __user *) arg); | |
1da177e4 LT |
437 | break; |
438 | default: | |
439 | err = do_fcntl(fd, cmd, arg, filp); | |
440 | break; | |
441 | } | |
442 | fput(filp); | |
443 | out: | |
444 | return err; | |
445 | } | |
446 | #endif | |
447 | ||
448 | /* Table to convert sigio signal codes into poll band bitmaps */ | |
449 | ||
fa3536cc | 450 | static const long band_table[NSIGPOLL] = { |
1da177e4 LT |
451 | POLLIN | POLLRDNORM, /* POLL_IN */ |
452 | POLLOUT | POLLWRNORM | POLLWRBAND, /* POLL_OUT */ | |
453 | POLLIN | POLLRDNORM | POLLMSG, /* POLL_MSG */ | |
454 | POLLERR, /* POLL_ERR */ | |
455 | POLLPRI | POLLRDBAND, /* POLL_PRI */ | |
456 | POLLHUP | POLLERR /* POLL_HUP */ | |
457 | }; | |
458 | ||
459 | static inline int sigio_perm(struct task_struct *p, | |
460 | struct fown_struct *fown, int sig) | |
461 | { | |
462 | return (((fown->euid == 0) || | |
463 | (fown->euid == p->suid) || (fown->euid == p->uid) || | |
464 | (fown->uid == p->suid) || (fown->uid == p->uid)) && | |
465 | !security_file_send_sigiotask(p, fown, sig)); | |
466 | } | |
467 | ||
468 | static void send_sigio_to_task(struct task_struct *p, | |
469 | struct fown_struct *fown, | |
470 | int fd, | |
471 | int reason) | |
472 | { | |
473 | if (!sigio_perm(p, fown, fown->signum)) | |
474 | return; | |
475 | ||
476 | switch (fown->signum) { | |
477 | siginfo_t si; | |
478 | default: | |
479 | /* Queue a rt signal with the appropriate fd as its | |
480 | value. We use SI_SIGIO as the source, not | |
481 | SI_KERNEL, since kernel signals always get | |
482 | delivered even if we can't queue. Failure to | |
483 | queue in this case _should_ be reported; we fall | |
484 | back to SIGIO in that case. --sct */ | |
485 | si.si_signo = fown->signum; | |
486 | si.si_errno = 0; | |
487 | si.si_code = reason; | |
488 | /* Make sure we are called with one of the POLL_* | |
489 | reasons, otherwise we could leak kernel stack into | |
490 | userspace. */ | |
f6298aab | 491 | BUG_ON((reason & __SI_MASK) != __SI_POLL); |
1da177e4 LT |
492 | if (reason - POLL_IN >= NSIGPOLL) |
493 | si.si_band = ~0L; | |
494 | else | |
495 | si.si_band = band_table[reason - POLL_IN]; | |
496 | si.si_fd = fd; | |
850d6fbe | 497 | if (!group_send_sig_info(fown->signum, &si, p)) |
1da177e4 LT |
498 | break; |
499 | /* fall-through: fall back on the old plain SIGIO signal */ | |
500 | case 0: | |
850d6fbe | 501 | group_send_sig_info(SIGIO, SEND_SIG_PRIV, p); |
1da177e4 LT |
502 | } |
503 | } | |
504 | ||
505 | void send_sigio(struct fown_struct *fown, int fd, int band) | |
506 | { | |
507 | struct task_struct *p; | |
609d7fa9 EB |
508 | enum pid_type type; |
509 | struct pid *pid; | |
1da177e4 LT |
510 | |
511 | read_lock(&fown->lock); | |
609d7fa9 | 512 | type = fown->pid_type; |
1da177e4 LT |
513 | pid = fown->pid; |
514 | if (!pid) | |
515 | goto out_unlock_fown; | |
516 | ||
517 | read_lock(&tasklist_lock); | |
609d7fa9 EB |
518 | do_each_pid_task(pid, type, p) { |
519 | send_sigio_to_task(p, fown, fd, band); | |
520 | } while_each_pid_task(pid, type, p); | |
1da177e4 LT |
521 | read_unlock(&tasklist_lock); |
522 | out_unlock_fown: | |
523 | read_unlock(&fown->lock); | |
524 | } | |
525 | ||
526 | static void send_sigurg_to_task(struct task_struct *p, | |
527 | struct fown_struct *fown) | |
528 | { | |
529 | if (sigio_perm(p, fown, SIGURG)) | |
850d6fbe | 530 | group_send_sig_info(SIGURG, SEND_SIG_PRIV, p); |
1da177e4 LT |
531 | } |
532 | ||
533 | int send_sigurg(struct fown_struct *fown) | |
534 | { | |
535 | struct task_struct *p; | |
609d7fa9 EB |
536 | enum pid_type type; |
537 | struct pid *pid; | |
538 | int ret = 0; | |
1da177e4 LT |
539 | |
540 | read_lock(&fown->lock); | |
609d7fa9 | 541 | type = fown->pid_type; |
1da177e4 LT |
542 | pid = fown->pid; |
543 | if (!pid) | |
544 | goto out_unlock_fown; | |
545 | ||
546 | ret = 1; | |
547 | ||
548 | read_lock(&tasklist_lock); | |
609d7fa9 EB |
549 | do_each_pid_task(pid, type, p) { |
550 | send_sigurg_to_task(p, fown); | |
551 | } while_each_pid_task(pid, type, p); | |
1da177e4 LT |
552 | read_unlock(&tasklist_lock); |
553 | out_unlock_fown: | |
554 | read_unlock(&fown->lock); | |
555 | return ret; | |
556 | } | |
557 | ||
558 | static DEFINE_RWLOCK(fasync_lock); | |
e18b890b | 559 | static struct kmem_cache *fasync_cache __read_mostly; |
1da177e4 LT |
560 | |
561 | /* | |
562 | * fasync_helper() is used by some character device drivers (mainly mice) | |
563 | * to set up the fasync queue. It returns negative on error, 0 if it did | |
564 | * no changes and positive if it added/deleted the entry. | |
565 | */ | |
566 | int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp) | |
567 | { | |
568 | struct fasync_struct *fa, **fp; | |
569 | struct fasync_struct *new = NULL; | |
570 | int result = 0; | |
571 | ||
572 | if (on) { | |
e94b1766 | 573 | new = kmem_cache_alloc(fasync_cache, GFP_KERNEL); |
1da177e4 LT |
574 | if (!new) |
575 | return -ENOMEM; | |
576 | } | |
577 | write_lock_irq(&fasync_lock); | |
578 | for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) { | |
579 | if (fa->fa_file == filp) { | |
580 | if(on) { | |
581 | fa->fa_fd = fd; | |
582 | kmem_cache_free(fasync_cache, new); | |
583 | } else { | |
584 | *fp = fa->fa_next; | |
585 | kmem_cache_free(fasync_cache, fa); | |
586 | result = 1; | |
587 | } | |
588 | goto out; | |
589 | } | |
590 | } | |
591 | ||
592 | if (on) { | |
593 | new->magic = FASYNC_MAGIC; | |
594 | new->fa_file = filp; | |
595 | new->fa_fd = fd; | |
596 | new->fa_next = *fapp; | |
597 | *fapp = new; | |
598 | result = 1; | |
599 | } | |
600 | out: | |
601 | write_unlock_irq(&fasync_lock); | |
602 | return result; | |
603 | } | |
604 | ||
605 | EXPORT_SYMBOL(fasync_helper); | |
606 | ||
607 | void __kill_fasync(struct fasync_struct *fa, int sig, int band) | |
608 | { | |
609 | while (fa) { | |
610 | struct fown_struct * fown; | |
611 | if (fa->magic != FASYNC_MAGIC) { | |
612 | printk(KERN_ERR "kill_fasync: bad magic number in " | |
613 | "fasync_struct!\n"); | |
614 | return; | |
615 | } | |
616 | fown = &fa->fa_file->f_owner; | |
617 | /* Don't send SIGURG to processes which have not set a | |
618 | queued signum: SIGURG has its own default signalling | |
619 | mechanism. */ | |
620 | if (!(sig == SIGURG && fown->signum == 0)) | |
621 | send_sigio(fown, fa->fa_fd, band); | |
622 | fa = fa->fa_next; | |
623 | } | |
624 | } | |
625 | ||
626 | EXPORT_SYMBOL(__kill_fasync); | |
627 | ||
628 | void kill_fasync(struct fasync_struct **fp, int sig, int band) | |
629 | { | |
630 | /* First a quick test without locking: usually | |
631 | * the list is empty. | |
632 | */ | |
633 | if (*fp) { | |
634 | read_lock(&fasync_lock); | |
635 | /* reread *fp after obtaining the lock */ | |
636 | __kill_fasync(*fp, sig, band); | |
637 | read_unlock(&fasync_lock); | |
638 | } | |
639 | } | |
640 | EXPORT_SYMBOL(kill_fasync); | |
641 | ||
642 | static int __init fasync_init(void) | |
643 | { | |
644 | fasync_cache = kmem_cache_create("fasync_cache", | |
20c2df83 | 645 | sizeof(struct fasync_struct), 0, SLAB_PANIC, NULL); |
1da177e4 LT |
646 | return 0; |
647 | } | |
648 | ||
649 | module_init(fasync_init) |