]>
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> | |
9f3acc31 | 12 | #include <linux/fdtable.h> |
16f7e0fe | 13 | #include <linux/capability.h> |
1da177e4 | 14 | #include <linux/dnotify.h> |
1da177e4 LT |
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> |
b488893a | 21 | #include <linux/pid_namespace.h> |
1da177e4 LT |
22 | |
23 | #include <asm/poll.h> | |
24 | #include <asm/siginfo.h> | |
25 | #include <asm/uaccess.h> | |
26 | ||
fc9b52cd | 27 | void set_close_on_exec(unsigned int fd, int flag) |
1da177e4 LT |
28 | { |
29 | struct files_struct *files = current->files; | |
badf1662 | 30 | struct fdtable *fdt; |
1da177e4 | 31 | spin_lock(&files->file_lock); |
badf1662 | 32 | fdt = files_fdtable(files); |
1da177e4 | 33 | if (flag) |
badf1662 | 34 | FD_SET(fd, fdt->close_on_exec); |
1da177e4 | 35 | else |
badf1662 | 36 | FD_CLR(fd, fdt->close_on_exec); |
1da177e4 LT |
37 | spin_unlock(&files->file_lock); |
38 | } | |
39 | ||
858119e1 | 40 | static int get_close_on_exec(unsigned int fd) |
1da177e4 LT |
41 | { |
42 | struct files_struct *files = current->files; | |
badf1662 | 43 | struct fdtable *fdt; |
1da177e4 | 44 | int res; |
b835996f | 45 | rcu_read_lock(); |
badf1662 DS |
46 | fdt = files_fdtable(files); |
47 | res = FD_ISSET(fd, fdt->close_on_exec); | |
b835996f | 48 | rcu_read_unlock(); |
1da177e4 LT |
49 | return res; |
50 | } | |
51 | ||
a26eab24 | 52 | SYSCALL_DEFINE3(dup3, unsigned int, oldfd, unsigned int, newfd, int, flags) |
1da177e4 LT |
53 | { |
54 | int err = -EBADF; | |
55 | struct file * file, *tofree; | |
56 | struct files_struct * files = current->files; | |
badf1662 | 57 | struct fdtable *fdt; |
1da177e4 | 58 | |
336dd1f7 UD |
59 | if ((flags & ~O_CLOEXEC) != 0) |
60 | return -EINVAL; | |
61 | ||
6c5d0512 AV |
62 | if (unlikely(oldfd == newfd)) |
63 | return -EINVAL; | |
64 | ||
1da177e4 | 65 | spin_lock(&files->file_lock); |
1da177e4 | 66 | err = expand_files(files, newfd); |
1b7e190b AV |
67 | file = fcheck(oldfd); |
68 | if (unlikely(!file)) | |
69 | goto Ebadf; | |
4e1e018e AV |
70 | if (unlikely(err < 0)) { |
71 | if (err == -EMFILE) | |
1b7e190b AV |
72 | goto Ebadf; |
73 | goto out_unlock; | |
4e1e018e | 74 | } |
1b7e190b AV |
75 | /* |
76 | * We need to detect attempts to do dup2() over allocated but still | |
77 | * not finished descriptor. NB: OpenBSD avoids that at the price of | |
78 | * extra work in their equivalent of fget() - they insert struct | |
79 | * file immediately after grabbing descriptor, mark it larval if | |
80 | * more work (e.g. actual opening) is needed and make sure that | |
81 | * fget() treats larval files as absent. Potentially interesting, | |
82 | * but while extra work in fget() is trivial, locking implications | |
83 | * and amount of surgery on open()-related paths in VFS are not. | |
84 | * FreeBSD fails with -EBADF in the same situation, NetBSD "solution" | |
85 | * deadlocks in rather amusing ways, AFAICS. All of that is out of | |
86 | * scope of POSIX or SUS, since neither considers shared descriptor | |
87 | * tables and this condition does not arise without those. | |
88 | */ | |
1da177e4 | 89 | err = -EBUSY; |
badf1662 DS |
90 | fdt = files_fdtable(files); |
91 | tofree = fdt->fd[newfd]; | |
92 | if (!tofree && FD_ISSET(newfd, fdt->open_fds)) | |
1b7e190b AV |
93 | goto out_unlock; |
94 | get_file(file); | |
ab2af1f5 | 95 | rcu_assign_pointer(fdt->fd[newfd], file); |
badf1662 | 96 | FD_SET(newfd, fdt->open_fds); |
336dd1f7 UD |
97 | if (flags & O_CLOEXEC) |
98 | FD_SET(newfd, fdt->close_on_exec); | |
99 | else | |
100 | FD_CLR(newfd, fdt->close_on_exec); | |
1da177e4 LT |
101 | spin_unlock(&files->file_lock); |
102 | ||
103 | if (tofree) | |
104 | filp_close(tofree, files); | |
1da177e4 | 105 | |
1b7e190b AV |
106 | return newfd; |
107 | ||
108 | Ebadf: | |
109 | err = -EBADF; | |
110 | out_unlock: | |
1da177e4 | 111 | spin_unlock(&files->file_lock); |
1b7e190b | 112 | return err; |
1da177e4 | 113 | } |
336dd1f7 | 114 | |
a26eab24 | 115 | SYSCALL_DEFINE2(dup2, unsigned int, oldfd, unsigned int, newfd) |
336dd1f7 | 116 | { |
6c5d0512 AV |
117 | if (unlikely(newfd == oldfd)) { /* corner case */ |
118 | struct files_struct *files = current->files; | |
2b79bc4f JM |
119 | int retval = oldfd; |
120 | ||
6c5d0512 AV |
121 | rcu_read_lock(); |
122 | if (!fcheck_files(files, oldfd)) | |
2b79bc4f | 123 | retval = -EBADF; |
6c5d0512 | 124 | rcu_read_unlock(); |
2b79bc4f | 125 | return retval; |
6c5d0512 | 126 | } |
336dd1f7 UD |
127 | return sys_dup3(oldfd, newfd, 0); |
128 | } | |
1da177e4 | 129 | |
a26eab24 | 130 | SYSCALL_DEFINE1(dup, unsigned int, fildes) |
1da177e4 LT |
131 | { |
132 | int ret = -EBADF; | |
1027abe8 AV |
133 | struct file *file = fget(fildes); |
134 | ||
135 | if (file) { | |
136 | ret = get_unused_fd(); | |
137 | if (ret >= 0) | |
138 | fd_install(ret, file); | |
139 | else | |
140 | fput(file); | |
141 | } | |
1da177e4 LT |
142 | return ret; |
143 | } | |
144 | ||
76398425 | 145 | #define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | O_DIRECT | O_NOATIME) |
1da177e4 LT |
146 | |
147 | static int setfl(int fd, struct file * filp, unsigned long arg) | |
148 | { | |
0f7fc9e4 | 149 | struct inode * inode = filp->f_path.dentry->d_inode; |
1da177e4 LT |
150 | int error = 0; |
151 | ||
7d95c8f2 | 152 | /* |
153 | * O_APPEND cannot be cleared if the file is marked as append-only | |
154 | * and the file is open for write. | |
155 | */ | |
156 | if (((arg ^ filp->f_flags) & O_APPEND) && IS_APPEND(inode)) | |
1da177e4 LT |
157 | return -EPERM; |
158 | ||
159 | /* O_NOATIME can only be set by the owner or superuser */ | |
160 | if ((arg & O_NOATIME) && !(filp->f_flags & O_NOATIME)) | |
3bd858ab | 161 | if (!is_owner_or_cap(inode)) |
1da177e4 LT |
162 | return -EPERM; |
163 | ||
164 | /* required for strict SunOS emulation */ | |
165 | if (O_NONBLOCK != O_NDELAY) | |
166 | if (arg & O_NDELAY) | |
167 | arg |= O_NONBLOCK; | |
168 | ||
169 | if (arg & O_DIRECT) { | |
170 | if (!filp->f_mapping || !filp->f_mapping->a_ops || | |
171 | !filp->f_mapping->a_ops->direct_IO) | |
172 | return -EINVAL; | |
173 | } | |
174 | ||
175 | if (filp->f_op && filp->f_op->check_flags) | |
176 | error = filp->f_op->check_flags(arg); | |
177 | if (error) | |
178 | return error; | |
179 | ||
218d11a8 | 180 | /* |
76398425 | 181 | * ->fasync() is responsible for setting the FASYNC bit. |
218d11a8 | 182 | */ |
76398425 JC |
183 | if (((arg ^ filp->f_flags) & FASYNC) && filp->f_op && |
184 | filp->f_op->fasync) { | |
185 | error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0); | |
186 | if (error < 0) | |
187 | goto out; | |
60aa4924 JC |
188 | if (error > 0) |
189 | error = 0; | |
1da177e4 | 190 | } |
db1dd4d3 | 191 | spin_lock(&filp->f_lock); |
1da177e4 | 192 | filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK); |
db1dd4d3 | 193 | spin_unlock(&filp->f_lock); |
76398425 | 194 | |
1da177e4 | 195 | out: |
1da177e4 LT |
196 | return error; |
197 | } | |
198 | ||
609d7fa9 | 199 | static void f_modown(struct file *filp, struct pid *pid, enum pid_type type, |
2f38d70f | 200 | int force) |
1da177e4 LT |
201 | { |
202 | write_lock_irq(&filp->f_owner.lock); | |
203 | if (force || !filp->f_owner.pid) { | |
609d7fa9 EB |
204 | put_pid(filp->f_owner.pid); |
205 | filp->f_owner.pid = get_pid(pid); | |
206 | filp->f_owner.pid_type = type; | |
2f38d70f ON |
207 | |
208 | if (pid) { | |
209 | const struct cred *cred = current_cred(); | |
210 | filp->f_owner.uid = cred->uid; | |
211 | filp->f_owner.euid = cred->euid; | |
212 | } | |
1da177e4 LT |
213 | } |
214 | write_unlock_irq(&filp->f_owner.lock); | |
215 | } | |
216 | ||
609d7fa9 EB |
217 | int __f_setown(struct file *filp, struct pid *pid, enum pid_type type, |
218 | int force) | |
1da177e4 LT |
219 | { |
220 | int err; | |
2f38d70f | 221 | |
1da177e4 LT |
222 | err = security_file_set_fowner(filp); |
223 | if (err) | |
224 | return err; | |
225 | ||
2f38d70f | 226 | f_modown(filp, pid, type, force); |
1da177e4 LT |
227 | return 0; |
228 | } | |
609d7fa9 | 229 | EXPORT_SYMBOL(__f_setown); |
1da177e4 | 230 | |
609d7fa9 EB |
231 | int f_setown(struct file *filp, unsigned long arg, int force) |
232 | { | |
233 | enum pid_type type; | |
234 | struct pid *pid; | |
235 | int who = arg; | |
236 | int result; | |
237 | type = PIDTYPE_PID; | |
238 | if (who < 0) { | |
239 | type = PIDTYPE_PGID; | |
240 | who = -who; | |
241 | } | |
242 | rcu_read_lock(); | |
b488893a | 243 | pid = find_vpid(who); |
609d7fa9 EB |
244 | result = __f_setown(filp, pid, type, force); |
245 | rcu_read_unlock(); | |
246 | return result; | |
247 | } | |
1da177e4 LT |
248 | EXPORT_SYMBOL(f_setown); |
249 | ||
250 | void f_delown(struct file *filp) | |
251 | { | |
2f38d70f | 252 | f_modown(filp, NULL, PIDTYPE_PID, 1); |
609d7fa9 EB |
253 | } |
254 | ||
255 | pid_t f_getown(struct file *filp) | |
256 | { | |
257 | pid_t pid; | |
43fa1adb | 258 | read_lock(&filp->f_owner.lock); |
6c5f3e7b | 259 | pid = pid_vnr(filp->f_owner.pid); |
609d7fa9 EB |
260 | if (filp->f_owner.pid_type == PIDTYPE_PGID) |
261 | pid = -pid; | |
43fa1adb | 262 | read_unlock(&filp->f_owner.lock); |
609d7fa9 | 263 | return pid; |
1da177e4 LT |
264 | } |
265 | ||
266 | static long do_fcntl(int fd, unsigned int cmd, unsigned long arg, | |
267 | struct file *filp) | |
268 | { | |
269 | long err = -EINVAL; | |
270 | ||
271 | switch (cmd) { | |
272 | case F_DUPFD: | |
22d2b35b | 273 | case F_DUPFD_CLOEXEC: |
4e1e018e AV |
274 | if (arg >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur) |
275 | break; | |
1027abe8 AV |
276 | err = alloc_fd(arg, cmd == F_DUPFD_CLOEXEC ? O_CLOEXEC : 0); |
277 | if (err >= 0) { | |
278 | get_file(filp); | |
279 | fd_install(err, filp); | |
280 | } | |
1da177e4 LT |
281 | break; |
282 | case F_GETFD: | |
283 | err = get_close_on_exec(fd) ? FD_CLOEXEC : 0; | |
284 | break; | |
285 | case F_SETFD: | |
286 | err = 0; | |
287 | set_close_on_exec(fd, arg & FD_CLOEXEC); | |
288 | break; | |
289 | case F_GETFL: | |
290 | err = filp->f_flags; | |
291 | break; | |
292 | case F_SETFL: | |
293 | err = setfl(fd, filp, arg); | |
294 | break; | |
295 | case F_GETLK: | |
296 | err = fcntl_getlk(filp, (struct flock __user *) arg); | |
297 | break; | |
298 | case F_SETLK: | |
299 | case F_SETLKW: | |
c293621b | 300 | err = fcntl_setlk(fd, filp, cmd, (struct flock __user *) arg); |
1da177e4 LT |
301 | break; |
302 | case F_GETOWN: | |
303 | /* | |
304 | * XXX If f_owner is a process group, the | |
305 | * negative return value will get converted | |
306 | * into an error. Oops. If we keep the | |
307 | * current syscall conventions, the only way | |
308 | * to fix this will be in libc. | |
309 | */ | |
609d7fa9 | 310 | err = f_getown(filp); |
1da177e4 LT |
311 | force_successful_syscall_return(); |
312 | break; | |
313 | case F_SETOWN: | |
314 | err = f_setown(filp, arg, 1); | |
315 | break; | |
316 | case F_GETSIG: | |
317 | err = filp->f_owner.signum; | |
318 | break; | |
319 | case F_SETSIG: | |
320 | /* arg == 0 restores default behaviour. */ | |
7ed20e1a | 321 | if (!valid_signal(arg)) { |
1da177e4 LT |
322 | break; |
323 | } | |
324 | err = 0; | |
325 | filp->f_owner.signum = arg; | |
326 | break; | |
327 | case F_GETLEASE: | |
328 | err = fcntl_getlease(filp); | |
329 | break; | |
330 | case F_SETLEASE: | |
331 | err = fcntl_setlease(fd, filp, arg); | |
332 | break; | |
333 | case F_NOTIFY: | |
334 | err = fcntl_dirnotify(fd, filp, arg); | |
335 | break; | |
336 | default: | |
337 | break; | |
338 | } | |
339 | return err; | |
340 | } | |
341 | ||
a26eab24 | 342 | SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd, unsigned long, arg) |
1da177e4 LT |
343 | { |
344 | struct file *filp; | |
345 | long err = -EBADF; | |
346 | ||
347 | filp = fget(fd); | |
348 | if (!filp) | |
349 | goto out; | |
350 | ||
351 | err = security_file_fcntl(filp, cmd, arg); | |
352 | if (err) { | |
353 | fput(filp); | |
354 | return err; | |
355 | } | |
356 | ||
357 | err = do_fcntl(fd, cmd, arg, filp); | |
358 | ||
359 | fput(filp); | |
360 | out: | |
361 | return err; | |
362 | } | |
363 | ||
364 | #if BITS_PER_LONG == 32 | |
a26eab24 HC |
365 | SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd, |
366 | unsigned long, arg) | |
1da177e4 LT |
367 | { |
368 | struct file * filp; | |
369 | long err; | |
370 | ||
371 | err = -EBADF; | |
372 | filp = fget(fd); | |
373 | if (!filp) | |
374 | goto out; | |
375 | ||
376 | err = security_file_fcntl(filp, cmd, arg); | |
377 | if (err) { | |
378 | fput(filp); | |
379 | return err; | |
380 | } | |
381 | err = -EBADF; | |
382 | ||
383 | switch (cmd) { | |
384 | case F_GETLK64: | |
385 | err = fcntl_getlk64(filp, (struct flock64 __user *) arg); | |
386 | break; | |
387 | case F_SETLK64: | |
388 | case F_SETLKW64: | |
c293621b PS |
389 | err = fcntl_setlk64(fd, filp, cmd, |
390 | (struct flock64 __user *) arg); | |
1da177e4 LT |
391 | break; |
392 | default: | |
393 | err = do_fcntl(fd, cmd, arg, filp); | |
394 | break; | |
395 | } | |
396 | fput(filp); | |
397 | out: | |
398 | return err; | |
399 | } | |
400 | #endif | |
401 | ||
402 | /* Table to convert sigio signal codes into poll band bitmaps */ | |
403 | ||
fa3536cc | 404 | static const long band_table[NSIGPOLL] = { |
1da177e4 LT |
405 | POLLIN | POLLRDNORM, /* POLL_IN */ |
406 | POLLOUT | POLLWRNORM | POLLWRBAND, /* POLL_OUT */ | |
407 | POLLIN | POLLRDNORM | POLLMSG, /* POLL_MSG */ | |
408 | POLLERR, /* POLL_ERR */ | |
409 | POLLPRI | POLLRDBAND, /* POLL_PRI */ | |
410 | POLLHUP | POLLERR /* POLL_HUP */ | |
411 | }; | |
412 | ||
413 | static inline int sigio_perm(struct task_struct *p, | |
414 | struct fown_struct *fown, int sig) | |
415 | { | |
c69e8d9c DH |
416 | const struct cred *cred; |
417 | int ret; | |
418 | ||
419 | rcu_read_lock(); | |
420 | cred = __task_cred(p); | |
421 | ret = ((fown->euid == 0 || | |
422 | fown->euid == cred->suid || fown->euid == cred->uid || | |
423 | fown->uid == cred->suid || fown->uid == cred->uid) && | |
424 | !security_file_send_sigiotask(p, fown, sig)); | |
425 | rcu_read_unlock(); | |
426 | return ret; | |
1da177e4 LT |
427 | } |
428 | ||
429 | static void send_sigio_to_task(struct task_struct *p, | |
8eeee4e2 | 430 | struct fown_struct *fown, |
1da177e4 LT |
431 | int fd, |
432 | int reason) | |
433 | { | |
8eeee4e2 ON |
434 | /* |
435 | * F_SETSIG can change ->signum lockless in parallel, make | |
436 | * sure we read it once and use the same value throughout. | |
437 | */ | |
438 | int signum = ACCESS_ONCE(fown->signum); | |
439 | ||
440 | if (!sigio_perm(p, fown, signum)) | |
1da177e4 LT |
441 | return; |
442 | ||
8eeee4e2 | 443 | switch (signum) { |
1da177e4 LT |
444 | siginfo_t si; |
445 | default: | |
446 | /* Queue a rt signal with the appropriate fd as its | |
447 | value. We use SI_SIGIO as the source, not | |
448 | SI_KERNEL, since kernel signals always get | |
449 | delivered even if we can't queue. Failure to | |
450 | queue in this case _should_ be reported; we fall | |
451 | back to SIGIO in that case. --sct */ | |
8eeee4e2 | 452 | si.si_signo = signum; |
1da177e4 LT |
453 | si.si_errno = 0; |
454 | si.si_code = reason; | |
455 | /* Make sure we are called with one of the POLL_* | |
456 | reasons, otherwise we could leak kernel stack into | |
457 | userspace. */ | |
f6298aab | 458 | BUG_ON((reason & __SI_MASK) != __SI_POLL); |
1da177e4 LT |
459 | if (reason - POLL_IN >= NSIGPOLL) |
460 | si.si_band = ~0L; | |
461 | else | |
462 | si.si_band = band_table[reason - POLL_IN]; | |
463 | si.si_fd = fd; | |
8eeee4e2 | 464 | if (!group_send_sig_info(signum, &si, p)) |
1da177e4 LT |
465 | break; |
466 | /* fall-through: fall back on the old plain SIGIO signal */ | |
467 | case 0: | |
850d6fbe | 468 | group_send_sig_info(SIGIO, SEND_SIG_PRIV, p); |
1da177e4 LT |
469 | } |
470 | } | |
471 | ||
472 | void send_sigio(struct fown_struct *fown, int fd, int band) | |
473 | { | |
474 | struct task_struct *p; | |
609d7fa9 EB |
475 | enum pid_type type; |
476 | struct pid *pid; | |
1da177e4 LT |
477 | |
478 | read_lock(&fown->lock); | |
609d7fa9 | 479 | type = fown->pid_type; |
1da177e4 LT |
480 | pid = fown->pid; |
481 | if (!pid) | |
482 | goto out_unlock_fown; | |
483 | ||
484 | read_lock(&tasklist_lock); | |
609d7fa9 EB |
485 | do_each_pid_task(pid, type, p) { |
486 | send_sigio_to_task(p, fown, fd, band); | |
487 | } while_each_pid_task(pid, type, p); | |
1da177e4 LT |
488 | read_unlock(&tasklist_lock); |
489 | out_unlock_fown: | |
490 | read_unlock(&fown->lock); | |
491 | } | |
492 | ||
493 | static void send_sigurg_to_task(struct task_struct *p, | |
494 | struct fown_struct *fown) | |
495 | { | |
496 | if (sigio_perm(p, fown, SIGURG)) | |
850d6fbe | 497 | group_send_sig_info(SIGURG, SEND_SIG_PRIV, p); |
1da177e4 LT |
498 | } |
499 | ||
500 | int send_sigurg(struct fown_struct *fown) | |
501 | { | |
502 | struct task_struct *p; | |
609d7fa9 EB |
503 | enum pid_type type; |
504 | struct pid *pid; | |
505 | int ret = 0; | |
1da177e4 LT |
506 | |
507 | read_lock(&fown->lock); | |
609d7fa9 | 508 | type = fown->pid_type; |
1da177e4 LT |
509 | pid = fown->pid; |
510 | if (!pid) | |
511 | goto out_unlock_fown; | |
512 | ||
513 | ret = 1; | |
514 | ||
515 | read_lock(&tasklist_lock); | |
609d7fa9 EB |
516 | do_each_pid_task(pid, type, p) { |
517 | send_sigurg_to_task(p, fown); | |
518 | } while_each_pid_task(pid, type, p); | |
1da177e4 LT |
519 | read_unlock(&tasklist_lock); |
520 | out_unlock_fown: | |
521 | read_unlock(&fown->lock); | |
522 | return ret; | |
523 | } | |
524 | ||
525 | static DEFINE_RWLOCK(fasync_lock); | |
e18b890b | 526 | static struct kmem_cache *fasync_cache __read_mostly; |
1da177e4 LT |
527 | |
528 | /* | |
76398425 | 529 | * fasync_helper() is used by almost all character device drivers |
1da177e4 LT |
530 | * to set up the fasync queue. It returns negative on error, 0 if it did |
531 | * no changes and positive if it added/deleted the entry. | |
532 | */ | |
533 | int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp) | |
534 | { | |
535 | struct fasync_struct *fa, **fp; | |
536 | struct fasync_struct *new = NULL; | |
537 | int result = 0; | |
538 | ||
539 | if (on) { | |
e94b1766 | 540 | new = kmem_cache_alloc(fasync_cache, GFP_KERNEL); |
1da177e4 LT |
541 | if (!new) |
542 | return -ENOMEM; | |
543 | } | |
4a6a4499 JC |
544 | |
545 | /* | |
546 | * We need to take f_lock first since it's not an IRQ-safe | |
547 | * lock. | |
548 | */ | |
549 | spin_lock(&filp->f_lock); | |
1da177e4 LT |
550 | write_lock_irq(&fasync_lock); |
551 | for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) { | |
552 | if (fa->fa_file == filp) { | |
553 | if(on) { | |
554 | fa->fa_fd = fd; | |
555 | kmem_cache_free(fasync_cache, new); | |
556 | } else { | |
557 | *fp = fa->fa_next; | |
558 | kmem_cache_free(fasync_cache, fa); | |
559 | result = 1; | |
560 | } | |
561 | goto out; | |
562 | } | |
563 | } | |
564 | ||
565 | if (on) { | |
566 | new->magic = FASYNC_MAGIC; | |
567 | new->fa_file = filp; | |
568 | new->fa_fd = fd; | |
569 | new->fa_next = *fapp; | |
570 | *fapp = new; | |
571 | result = 1; | |
572 | } | |
573 | out: | |
76398425 JC |
574 | if (on) |
575 | filp->f_flags |= FASYNC; | |
576 | else | |
577 | filp->f_flags &= ~FASYNC; | |
1da177e4 | 578 | write_unlock_irq(&fasync_lock); |
4a6a4499 | 579 | spin_unlock(&filp->f_lock); |
1da177e4 LT |
580 | return result; |
581 | } | |
582 | ||
583 | EXPORT_SYMBOL(fasync_helper); | |
584 | ||
585 | void __kill_fasync(struct fasync_struct *fa, int sig, int band) | |
586 | { | |
587 | while (fa) { | |
588 | struct fown_struct * fown; | |
589 | if (fa->magic != FASYNC_MAGIC) { | |
590 | printk(KERN_ERR "kill_fasync: bad magic number in " | |
591 | "fasync_struct!\n"); | |
592 | return; | |
593 | } | |
594 | fown = &fa->fa_file->f_owner; | |
595 | /* Don't send SIGURG to processes which have not set a | |
596 | queued signum: SIGURG has its own default signalling | |
597 | mechanism. */ | |
598 | if (!(sig == SIGURG && fown->signum == 0)) | |
599 | send_sigio(fown, fa->fa_fd, band); | |
600 | fa = fa->fa_next; | |
601 | } | |
602 | } | |
603 | ||
604 | EXPORT_SYMBOL(__kill_fasync); | |
605 | ||
606 | void kill_fasync(struct fasync_struct **fp, int sig, int band) | |
607 | { | |
608 | /* First a quick test without locking: usually | |
609 | * the list is empty. | |
610 | */ | |
611 | if (*fp) { | |
612 | read_lock(&fasync_lock); | |
613 | /* reread *fp after obtaining the lock */ | |
614 | __kill_fasync(*fp, sig, band); | |
615 | read_unlock(&fasync_lock); | |
616 | } | |
617 | } | |
618 | EXPORT_SYMBOL(kill_fasync); | |
619 | ||
620 | static int __init fasync_init(void) | |
621 | { | |
622 | fasync_cache = kmem_cache_create("fasync_cache", | |
20c2df83 | 623 | sizeof(struct fasync_struct), 0, SLAB_PANIC, NULL); |
1da177e4 LT |
624 | return 0; |
625 | } | |
626 | ||
627 | module_init(fasync_init) |