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Commit | Line | Data |
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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> |
218d11a8 | 22 | #include <linux/smp_lock.h> |
1da177e4 LT |
23 | |
24 | #include <asm/poll.h> | |
25 | #include <asm/siginfo.h> | |
26 | #include <asm/uaccess.h> | |
27 | ||
fc9b52cd | 28 | void set_close_on_exec(unsigned int fd, int flag) |
1da177e4 LT |
29 | { |
30 | struct files_struct *files = current->files; | |
badf1662 | 31 | struct fdtable *fdt; |
1da177e4 | 32 | spin_lock(&files->file_lock); |
badf1662 | 33 | fdt = files_fdtable(files); |
1da177e4 | 34 | if (flag) |
badf1662 | 35 | FD_SET(fd, fdt->close_on_exec); |
1da177e4 | 36 | else |
badf1662 | 37 | FD_CLR(fd, fdt->close_on_exec); |
1da177e4 LT |
38 | spin_unlock(&files->file_lock); |
39 | } | |
40 | ||
858119e1 | 41 | static int get_close_on_exec(unsigned int fd) |
1da177e4 LT |
42 | { |
43 | struct files_struct *files = current->files; | |
badf1662 | 44 | struct fdtable *fdt; |
1da177e4 | 45 | int res; |
b835996f | 46 | rcu_read_lock(); |
badf1662 DS |
47 | fdt = files_fdtable(files); |
48 | res = FD_ISSET(fd, fdt->close_on_exec); | |
b835996f | 49 | rcu_read_unlock(); |
1da177e4 LT |
50 | return res; |
51 | } | |
52 | ||
a26eab24 | 53 | SYSCALL_DEFINE3(dup3, unsigned int, oldfd, unsigned int, newfd, int, flags) |
1da177e4 LT |
54 | { |
55 | int err = -EBADF; | |
56 | struct file * file, *tofree; | |
57 | struct files_struct * files = current->files; | |
badf1662 | 58 | struct fdtable *fdt; |
1da177e4 | 59 | |
336dd1f7 UD |
60 | if ((flags & ~O_CLOEXEC) != 0) |
61 | return -EINVAL; | |
62 | ||
6c5d0512 AV |
63 | if (unlikely(oldfd == newfd)) |
64 | return -EINVAL; | |
65 | ||
1da177e4 | 66 | spin_lock(&files->file_lock); |
1da177e4 | 67 | err = expand_files(files, newfd); |
1b7e190b AV |
68 | file = fcheck(oldfd); |
69 | if (unlikely(!file)) | |
70 | goto Ebadf; | |
4e1e018e AV |
71 | if (unlikely(err < 0)) { |
72 | if (err == -EMFILE) | |
1b7e190b AV |
73 | goto Ebadf; |
74 | goto out_unlock; | |
4e1e018e | 75 | } |
1b7e190b AV |
76 | /* |
77 | * We need to detect attempts to do dup2() over allocated but still | |
78 | * not finished descriptor. NB: OpenBSD avoids that at the price of | |
79 | * extra work in their equivalent of fget() - they insert struct | |
80 | * file immediately after grabbing descriptor, mark it larval if | |
81 | * more work (e.g. actual opening) is needed and make sure that | |
82 | * fget() treats larval files as absent. Potentially interesting, | |
83 | * but while extra work in fget() is trivial, locking implications | |
84 | * and amount of surgery on open()-related paths in VFS are not. | |
85 | * FreeBSD fails with -EBADF in the same situation, NetBSD "solution" | |
86 | * deadlocks in rather amusing ways, AFAICS. All of that is out of | |
87 | * scope of POSIX or SUS, since neither considers shared descriptor | |
88 | * tables and this condition does not arise without those. | |
89 | */ | |
1da177e4 | 90 | err = -EBUSY; |
badf1662 DS |
91 | fdt = files_fdtable(files); |
92 | tofree = fdt->fd[newfd]; | |
93 | if (!tofree && FD_ISSET(newfd, fdt->open_fds)) | |
1b7e190b AV |
94 | goto out_unlock; |
95 | get_file(file); | |
ab2af1f5 | 96 | rcu_assign_pointer(fdt->fd[newfd], file); |
badf1662 | 97 | FD_SET(newfd, fdt->open_fds); |
336dd1f7 UD |
98 | if (flags & O_CLOEXEC) |
99 | FD_SET(newfd, fdt->close_on_exec); | |
100 | else | |
101 | FD_CLR(newfd, fdt->close_on_exec); | |
1da177e4 LT |
102 | spin_unlock(&files->file_lock); |
103 | ||
104 | if (tofree) | |
105 | filp_close(tofree, files); | |
1da177e4 | 106 | |
1b7e190b AV |
107 | return newfd; |
108 | ||
109 | Ebadf: | |
110 | err = -EBADF; | |
111 | out_unlock: | |
1da177e4 | 112 | spin_unlock(&files->file_lock); |
1b7e190b | 113 | return err; |
1da177e4 | 114 | } |
336dd1f7 | 115 | |
a26eab24 | 116 | SYSCALL_DEFINE2(dup2, unsigned int, oldfd, unsigned int, newfd) |
336dd1f7 | 117 | { |
6c5d0512 AV |
118 | if (unlikely(newfd == oldfd)) { /* corner case */ |
119 | struct files_struct *files = current->files; | |
120 | rcu_read_lock(); | |
121 | if (!fcheck_files(files, oldfd)) | |
122 | oldfd = -EBADF; | |
123 | rcu_read_unlock(); | |
124 | return oldfd; | |
125 | } | |
336dd1f7 UD |
126 | return sys_dup3(oldfd, newfd, 0); |
127 | } | |
1da177e4 | 128 | |
a26eab24 | 129 | SYSCALL_DEFINE1(dup, unsigned int, fildes) |
1da177e4 LT |
130 | { |
131 | int ret = -EBADF; | |
1027abe8 AV |
132 | struct file *file = fget(fildes); |
133 | ||
134 | if (file) { | |
135 | ret = get_unused_fd(); | |
136 | if (ret >= 0) | |
137 | fd_install(ret, file); | |
138 | else | |
139 | fput(file); | |
140 | } | |
1da177e4 LT |
141 | return ret; |
142 | } | |
143 | ||
76398425 | 144 | #define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | O_DIRECT | O_NOATIME) |
1da177e4 LT |
145 | |
146 | static int setfl(int fd, struct file * filp, unsigned long arg) | |
147 | { | |
0f7fc9e4 | 148 | struct inode * inode = filp->f_path.dentry->d_inode; |
1da177e4 LT |
149 | int error = 0; |
150 | ||
7d95c8f2 | 151 | /* |
152 | * O_APPEND cannot be cleared if the file is marked as append-only | |
153 | * and the file is open for write. | |
154 | */ | |
155 | if (((arg ^ filp->f_flags) & O_APPEND) && IS_APPEND(inode)) | |
1da177e4 LT |
156 | return -EPERM; |
157 | ||
158 | /* O_NOATIME can only be set by the owner or superuser */ | |
159 | if ((arg & O_NOATIME) && !(filp->f_flags & O_NOATIME)) | |
3bd858ab | 160 | if (!is_owner_or_cap(inode)) |
1da177e4 LT |
161 | return -EPERM; |
162 | ||
163 | /* required for strict SunOS emulation */ | |
164 | if (O_NONBLOCK != O_NDELAY) | |
165 | if (arg & O_NDELAY) | |
166 | arg |= O_NONBLOCK; | |
167 | ||
168 | if (arg & O_DIRECT) { | |
169 | if (!filp->f_mapping || !filp->f_mapping->a_ops || | |
170 | !filp->f_mapping->a_ops->direct_IO) | |
171 | return -EINVAL; | |
172 | } | |
173 | ||
174 | if (filp->f_op && filp->f_op->check_flags) | |
175 | error = filp->f_op->check_flags(arg); | |
176 | if (error) | |
177 | return error; | |
178 | ||
218d11a8 | 179 | /* |
76398425 | 180 | * ->fasync() is responsible for setting the FASYNC bit. |
218d11a8 | 181 | */ |
76398425 JC |
182 | if (((arg ^ filp->f_flags) & FASYNC) && filp->f_op && |
183 | filp->f_op->fasync) { | |
184 | error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0); | |
185 | if (error < 0) | |
186 | goto out; | |
1da177e4 | 187 | } |
db1dd4d3 | 188 | spin_lock(&filp->f_lock); |
1da177e4 | 189 | filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK); |
db1dd4d3 | 190 | spin_unlock(&filp->f_lock); |
76398425 | 191 | |
1da177e4 | 192 | out: |
1da177e4 LT |
193 | return error; |
194 | } | |
195 | ||
609d7fa9 | 196 | static void f_modown(struct file *filp, struct pid *pid, enum pid_type type, |
1da177e4 LT |
197 | uid_t uid, uid_t euid, int force) |
198 | { | |
199 | write_lock_irq(&filp->f_owner.lock); | |
200 | if (force || !filp->f_owner.pid) { | |
609d7fa9 EB |
201 | put_pid(filp->f_owner.pid); |
202 | filp->f_owner.pid = get_pid(pid); | |
203 | filp->f_owner.pid_type = type; | |
1da177e4 LT |
204 | filp->f_owner.uid = uid; |
205 | filp->f_owner.euid = euid; | |
206 | } | |
207 | write_unlock_irq(&filp->f_owner.lock); | |
208 | } | |
209 | ||
609d7fa9 EB |
210 | int __f_setown(struct file *filp, struct pid *pid, enum pid_type type, |
211 | int force) | |
1da177e4 | 212 | { |
86a264ab | 213 | const struct cred *cred = current_cred(); |
1da177e4 LT |
214 | int err; |
215 | ||
216 | err = security_file_set_fowner(filp); | |
217 | if (err) | |
218 | return err; | |
219 | ||
86a264ab | 220 | f_modown(filp, pid, type, cred->uid, cred->euid, force); |
1da177e4 LT |
221 | return 0; |
222 | } | |
609d7fa9 | 223 | EXPORT_SYMBOL(__f_setown); |
1da177e4 | 224 | |
609d7fa9 EB |
225 | int f_setown(struct file *filp, unsigned long arg, int force) |
226 | { | |
227 | enum pid_type type; | |
228 | struct pid *pid; | |
229 | int who = arg; | |
230 | int result; | |
231 | type = PIDTYPE_PID; | |
232 | if (who < 0) { | |
233 | type = PIDTYPE_PGID; | |
234 | who = -who; | |
235 | } | |
236 | rcu_read_lock(); | |
b488893a | 237 | pid = find_vpid(who); |
609d7fa9 EB |
238 | result = __f_setown(filp, pid, type, force); |
239 | rcu_read_unlock(); | |
240 | return result; | |
241 | } | |
1da177e4 LT |
242 | EXPORT_SYMBOL(f_setown); |
243 | ||
244 | void f_delown(struct file *filp) | |
245 | { | |
609d7fa9 EB |
246 | f_modown(filp, NULL, PIDTYPE_PID, 0, 0, 1); |
247 | } | |
248 | ||
249 | pid_t f_getown(struct file *filp) | |
250 | { | |
251 | pid_t pid; | |
43fa1adb | 252 | read_lock(&filp->f_owner.lock); |
6c5f3e7b | 253 | pid = pid_vnr(filp->f_owner.pid); |
609d7fa9 EB |
254 | if (filp->f_owner.pid_type == PIDTYPE_PGID) |
255 | pid = -pid; | |
43fa1adb | 256 | read_unlock(&filp->f_owner.lock); |
609d7fa9 | 257 | return pid; |
1da177e4 LT |
258 | } |
259 | ||
260 | static long do_fcntl(int fd, unsigned int cmd, unsigned long arg, | |
261 | struct file *filp) | |
262 | { | |
263 | long err = -EINVAL; | |
264 | ||
265 | switch (cmd) { | |
266 | case F_DUPFD: | |
22d2b35b | 267 | case F_DUPFD_CLOEXEC: |
4e1e018e AV |
268 | if (arg >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur) |
269 | break; | |
1027abe8 AV |
270 | err = alloc_fd(arg, cmd == F_DUPFD_CLOEXEC ? O_CLOEXEC : 0); |
271 | if (err >= 0) { | |
272 | get_file(filp); | |
273 | fd_install(err, filp); | |
274 | } | |
1da177e4 LT |
275 | break; |
276 | case F_GETFD: | |
277 | err = get_close_on_exec(fd) ? FD_CLOEXEC : 0; | |
278 | break; | |
279 | case F_SETFD: | |
280 | err = 0; | |
281 | set_close_on_exec(fd, arg & FD_CLOEXEC); | |
282 | break; | |
283 | case F_GETFL: | |
284 | err = filp->f_flags; | |
285 | break; | |
286 | case F_SETFL: | |
287 | err = setfl(fd, filp, arg); | |
288 | break; | |
289 | case F_GETLK: | |
290 | err = fcntl_getlk(filp, (struct flock __user *) arg); | |
291 | break; | |
292 | case F_SETLK: | |
293 | case F_SETLKW: | |
c293621b | 294 | err = fcntl_setlk(fd, filp, cmd, (struct flock __user *) arg); |
1da177e4 LT |
295 | break; |
296 | case F_GETOWN: | |
297 | /* | |
298 | * XXX If f_owner is a process group, the | |
299 | * negative return value will get converted | |
300 | * into an error. Oops. If we keep the | |
301 | * current syscall conventions, the only way | |
302 | * to fix this will be in libc. | |
303 | */ | |
609d7fa9 | 304 | err = f_getown(filp); |
1da177e4 LT |
305 | force_successful_syscall_return(); |
306 | break; | |
307 | case F_SETOWN: | |
308 | err = f_setown(filp, arg, 1); | |
309 | break; | |
310 | case F_GETSIG: | |
311 | err = filp->f_owner.signum; | |
312 | break; | |
313 | case F_SETSIG: | |
314 | /* arg == 0 restores default behaviour. */ | |
7ed20e1a | 315 | if (!valid_signal(arg)) { |
1da177e4 LT |
316 | break; |
317 | } | |
318 | err = 0; | |
319 | filp->f_owner.signum = arg; | |
320 | break; | |
321 | case F_GETLEASE: | |
322 | err = fcntl_getlease(filp); | |
323 | break; | |
324 | case F_SETLEASE: | |
325 | err = fcntl_setlease(fd, filp, arg); | |
326 | break; | |
327 | case F_NOTIFY: | |
328 | err = fcntl_dirnotify(fd, filp, arg); | |
329 | break; | |
330 | default: | |
331 | break; | |
332 | } | |
333 | return err; | |
334 | } | |
335 | ||
a26eab24 | 336 | SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd, unsigned long, arg) |
1da177e4 LT |
337 | { |
338 | struct file *filp; | |
339 | long err = -EBADF; | |
340 | ||
341 | filp = fget(fd); | |
342 | if (!filp) | |
343 | goto out; | |
344 | ||
345 | err = security_file_fcntl(filp, cmd, arg); | |
346 | if (err) { | |
347 | fput(filp); | |
348 | return err; | |
349 | } | |
350 | ||
351 | err = do_fcntl(fd, cmd, arg, filp); | |
352 | ||
353 | fput(filp); | |
354 | out: | |
355 | return err; | |
356 | } | |
357 | ||
358 | #if BITS_PER_LONG == 32 | |
a26eab24 HC |
359 | SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd, |
360 | unsigned long, arg) | |
1da177e4 LT |
361 | { |
362 | struct file * filp; | |
363 | long err; | |
364 | ||
365 | err = -EBADF; | |
366 | filp = fget(fd); | |
367 | if (!filp) | |
368 | goto out; | |
369 | ||
370 | err = security_file_fcntl(filp, cmd, arg); | |
371 | if (err) { | |
372 | fput(filp); | |
373 | return err; | |
374 | } | |
375 | err = -EBADF; | |
376 | ||
377 | switch (cmd) { | |
378 | case F_GETLK64: | |
379 | err = fcntl_getlk64(filp, (struct flock64 __user *) arg); | |
380 | break; | |
381 | case F_SETLK64: | |
382 | case F_SETLKW64: | |
c293621b PS |
383 | err = fcntl_setlk64(fd, filp, cmd, |
384 | (struct flock64 __user *) arg); | |
1da177e4 LT |
385 | break; |
386 | default: | |
387 | err = do_fcntl(fd, cmd, arg, filp); | |
388 | break; | |
389 | } | |
390 | fput(filp); | |
391 | out: | |
392 | return err; | |
393 | } | |
394 | #endif | |
395 | ||
396 | /* Table to convert sigio signal codes into poll band bitmaps */ | |
397 | ||
fa3536cc | 398 | static const long band_table[NSIGPOLL] = { |
1da177e4 LT |
399 | POLLIN | POLLRDNORM, /* POLL_IN */ |
400 | POLLOUT | POLLWRNORM | POLLWRBAND, /* POLL_OUT */ | |
401 | POLLIN | POLLRDNORM | POLLMSG, /* POLL_MSG */ | |
402 | POLLERR, /* POLL_ERR */ | |
403 | POLLPRI | POLLRDBAND, /* POLL_PRI */ | |
404 | POLLHUP | POLLERR /* POLL_HUP */ | |
405 | }; | |
406 | ||
407 | static inline int sigio_perm(struct task_struct *p, | |
408 | struct fown_struct *fown, int sig) | |
409 | { | |
c69e8d9c DH |
410 | const struct cred *cred; |
411 | int ret; | |
412 | ||
413 | rcu_read_lock(); | |
414 | cred = __task_cred(p); | |
415 | ret = ((fown->euid == 0 || | |
416 | fown->euid == cred->suid || fown->euid == cred->uid || | |
417 | fown->uid == cred->suid || fown->uid == cred->uid) && | |
418 | !security_file_send_sigiotask(p, fown, sig)); | |
419 | rcu_read_unlock(); | |
420 | return ret; | |
1da177e4 LT |
421 | } |
422 | ||
423 | static void send_sigio_to_task(struct task_struct *p, | |
424 | struct fown_struct *fown, | |
425 | int fd, | |
426 | int reason) | |
427 | { | |
428 | if (!sigio_perm(p, fown, fown->signum)) | |
429 | return; | |
430 | ||
431 | switch (fown->signum) { | |
432 | siginfo_t si; | |
433 | default: | |
434 | /* Queue a rt signal with the appropriate fd as its | |
435 | value. We use SI_SIGIO as the source, not | |
436 | SI_KERNEL, since kernel signals always get | |
437 | delivered even if we can't queue. Failure to | |
438 | queue in this case _should_ be reported; we fall | |
439 | back to SIGIO in that case. --sct */ | |
440 | si.si_signo = fown->signum; | |
441 | si.si_errno = 0; | |
442 | si.si_code = reason; | |
443 | /* Make sure we are called with one of the POLL_* | |
444 | reasons, otherwise we could leak kernel stack into | |
445 | userspace. */ | |
f6298aab | 446 | BUG_ON((reason & __SI_MASK) != __SI_POLL); |
1da177e4 LT |
447 | if (reason - POLL_IN >= NSIGPOLL) |
448 | si.si_band = ~0L; | |
449 | else | |
450 | si.si_band = band_table[reason - POLL_IN]; | |
451 | si.si_fd = fd; | |
850d6fbe | 452 | if (!group_send_sig_info(fown->signum, &si, p)) |
1da177e4 LT |
453 | break; |
454 | /* fall-through: fall back on the old plain SIGIO signal */ | |
455 | case 0: | |
850d6fbe | 456 | group_send_sig_info(SIGIO, SEND_SIG_PRIV, p); |
1da177e4 LT |
457 | } |
458 | } | |
459 | ||
460 | void send_sigio(struct fown_struct *fown, int fd, int band) | |
461 | { | |
462 | struct task_struct *p; | |
609d7fa9 EB |
463 | enum pid_type type; |
464 | struct pid *pid; | |
1da177e4 LT |
465 | |
466 | read_lock(&fown->lock); | |
609d7fa9 | 467 | type = fown->pid_type; |
1da177e4 LT |
468 | pid = fown->pid; |
469 | if (!pid) | |
470 | goto out_unlock_fown; | |
471 | ||
472 | read_lock(&tasklist_lock); | |
609d7fa9 EB |
473 | do_each_pid_task(pid, type, p) { |
474 | send_sigio_to_task(p, fown, fd, band); | |
475 | } while_each_pid_task(pid, type, p); | |
1da177e4 LT |
476 | read_unlock(&tasklist_lock); |
477 | out_unlock_fown: | |
478 | read_unlock(&fown->lock); | |
479 | } | |
480 | ||
481 | static void send_sigurg_to_task(struct task_struct *p, | |
482 | struct fown_struct *fown) | |
483 | { | |
484 | if (sigio_perm(p, fown, SIGURG)) | |
850d6fbe | 485 | group_send_sig_info(SIGURG, SEND_SIG_PRIV, p); |
1da177e4 LT |
486 | } |
487 | ||
488 | int send_sigurg(struct fown_struct *fown) | |
489 | { | |
490 | struct task_struct *p; | |
609d7fa9 EB |
491 | enum pid_type type; |
492 | struct pid *pid; | |
493 | int ret = 0; | |
1da177e4 LT |
494 | |
495 | read_lock(&fown->lock); | |
609d7fa9 | 496 | type = fown->pid_type; |
1da177e4 LT |
497 | pid = fown->pid; |
498 | if (!pid) | |
499 | goto out_unlock_fown; | |
500 | ||
501 | ret = 1; | |
502 | ||
503 | read_lock(&tasklist_lock); | |
609d7fa9 EB |
504 | do_each_pid_task(pid, type, p) { |
505 | send_sigurg_to_task(p, fown); | |
506 | } while_each_pid_task(pid, type, p); | |
1da177e4 LT |
507 | read_unlock(&tasklist_lock); |
508 | out_unlock_fown: | |
509 | read_unlock(&fown->lock); | |
510 | return ret; | |
511 | } | |
512 | ||
513 | static DEFINE_RWLOCK(fasync_lock); | |
e18b890b | 514 | static struct kmem_cache *fasync_cache __read_mostly; |
1da177e4 LT |
515 | |
516 | /* | |
76398425 | 517 | * fasync_helper() is used by almost all character device drivers |
1da177e4 LT |
518 | * to set up the fasync queue. It returns negative on error, 0 if it did |
519 | * no changes and positive if it added/deleted the entry. | |
520 | */ | |
521 | int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp) | |
522 | { | |
523 | struct fasync_struct *fa, **fp; | |
524 | struct fasync_struct *new = NULL; | |
525 | int result = 0; | |
526 | ||
527 | if (on) { | |
e94b1766 | 528 | new = kmem_cache_alloc(fasync_cache, GFP_KERNEL); |
1da177e4 LT |
529 | if (!new) |
530 | return -ENOMEM; | |
531 | } | |
532 | write_lock_irq(&fasync_lock); | |
533 | for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) { | |
534 | if (fa->fa_file == filp) { | |
535 | if(on) { | |
536 | fa->fa_fd = fd; | |
537 | kmem_cache_free(fasync_cache, new); | |
538 | } else { | |
539 | *fp = fa->fa_next; | |
540 | kmem_cache_free(fasync_cache, fa); | |
541 | result = 1; | |
542 | } | |
543 | goto out; | |
544 | } | |
545 | } | |
546 | ||
547 | if (on) { | |
548 | new->magic = FASYNC_MAGIC; | |
549 | new->fa_file = filp; | |
550 | new->fa_fd = fd; | |
551 | new->fa_next = *fapp; | |
552 | *fapp = new; | |
553 | result = 1; | |
554 | } | |
555 | out: | |
76398425 JC |
556 | /* Fix up FASYNC bit while still holding fasync_lock */ |
557 | spin_lock(&filp->f_lock); | |
558 | if (on) | |
559 | filp->f_flags |= FASYNC; | |
560 | else | |
561 | filp->f_flags &= ~FASYNC; | |
562 | spin_unlock(&filp->f_lock); | |
1da177e4 LT |
563 | write_unlock_irq(&fasync_lock); |
564 | return result; | |
565 | } | |
566 | ||
567 | EXPORT_SYMBOL(fasync_helper); | |
568 | ||
569 | void __kill_fasync(struct fasync_struct *fa, int sig, int band) | |
570 | { | |
571 | while (fa) { | |
572 | struct fown_struct * fown; | |
573 | if (fa->magic != FASYNC_MAGIC) { | |
574 | printk(KERN_ERR "kill_fasync: bad magic number in " | |
575 | "fasync_struct!\n"); | |
576 | return; | |
577 | } | |
578 | fown = &fa->fa_file->f_owner; | |
579 | /* Don't send SIGURG to processes which have not set a | |
580 | queued signum: SIGURG has its own default signalling | |
581 | mechanism. */ | |
582 | if (!(sig == SIGURG && fown->signum == 0)) | |
583 | send_sigio(fown, fa->fa_fd, band); | |
584 | fa = fa->fa_next; | |
585 | } | |
586 | } | |
587 | ||
588 | EXPORT_SYMBOL(__kill_fasync); | |
589 | ||
590 | void kill_fasync(struct fasync_struct **fp, int sig, int band) | |
591 | { | |
592 | /* First a quick test without locking: usually | |
593 | * the list is empty. | |
594 | */ | |
595 | if (*fp) { | |
596 | read_lock(&fasync_lock); | |
597 | /* reread *fp after obtaining the lock */ | |
598 | __kill_fasync(*fp, sig, band); | |
599 | read_unlock(&fasync_lock); | |
600 | } | |
601 | } | |
602 | EXPORT_SYMBOL(kill_fasync); | |
603 | ||
604 | static int __init fasync_init(void) | |
605 | { | |
606 | fasync_cache = kmem_cache_create("fasync_cache", | |
20c2df83 | 607 | sizeof(struct fasync_struct), 0, SLAB_PANIC, NULL); |
1da177e4 LT |
608 | return 0; |
609 | } | |
610 | ||
611 | module_init(fasync_init) |