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 LT |
14 | #include <linux/dnotify.h> |
15 | #include <linux/smp_lock.h> | |
16 | #include <linux/slab.h> | |
17 | #include <linux/module.h> | |
18 | #include <linux/security.h> | |
19 | #include <linux/ptrace.h> | |
7ed20e1a | 20 | #include <linux/signal.h> |
ab2af1f5 | 21 | #include <linux/rcupdate.h> |
b488893a | 22 | #include <linux/pid_namespace.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 | ||
53 | /* | |
54 | * locate_fd finds a free file descriptor in the open_fds fdset, | |
55 | * expanding the fd arrays if necessary. Must be called with the | |
56 | * file_lock held for write. | |
57 | */ | |
58 | ||
f8f95702 | 59 | static int locate_fd(unsigned int orig_start, int cloexec) |
1da177e4 | 60 | { |
f8f95702 | 61 | struct files_struct *files = current->files; |
1da177e4 LT |
62 | unsigned int newfd; |
63 | unsigned int start; | |
64 | int error; | |
badf1662 | 65 | struct fdtable *fdt; |
1da177e4 | 66 | |
f8f95702 AV |
67 | spin_lock(&files->file_lock); |
68 | ||
1da177e4 LT |
69 | error = -EINVAL; |
70 | if (orig_start >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur) | |
71 | goto out; | |
72 | ||
73 | repeat: | |
ab2af1f5 | 74 | fdt = files_fdtable(files); |
1da177e4 LT |
75 | /* |
76 | * Someone might have closed fd's in the range | |
badf1662 | 77 | * orig_start..fdt->next_fd |
1da177e4 LT |
78 | */ |
79 | start = orig_start; | |
0c9e63fd ED |
80 | if (start < files->next_fd) |
81 | start = files->next_fd; | |
1da177e4 LT |
82 | |
83 | newfd = start; | |
bbea9f69 | 84 | if (start < fdt->max_fds) |
badf1662 | 85 | newfd = find_next_zero_bit(fdt->open_fds->fds_bits, |
bbea9f69 | 86 | fdt->max_fds, start); |
1da177e4 LT |
87 | |
88 | error = -EMFILE; | |
89 | if (newfd >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur) | |
90 | goto out; | |
91 | ||
92 | error = expand_files(files, newfd); | |
93 | if (error < 0) | |
94 | goto out; | |
95 | ||
96 | /* | |
97 | * If we needed to expand the fs array we | |
98 | * might have blocked - try again. | |
99 | */ | |
100 | if (error) | |
101 | goto repeat; | |
102 | ||
0c9e63fd ED |
103 | if (start <= files->next_fd) |
104 | files->next_fd = newfd + 1; | |
ab2af1f5 | 105 | |
f8f95702 AV |
106 | FD_SET(newfd, fdt->open_fds); |
107 | if (cloexec) | |
108 | FD_SET(newfd, fdt->close_on_exec); | |
109 | else | |
110 | FD_CLR(newfd, fdt->close_on_exec); | |
1da177e4 | 111 | error = newfd; |
f8f95702 | 112 | |
1da177e4 | 113 | out: |
f8f95702 | 114 | spin_unlock(&files->file_lock); |
1da177e4 LT |
115 | return error; |
116 | } | |
117 | ||
22d2b35b | 118 | static int dupfd(struct file *file, unsigned int start, int cloexec) |
1da177e4 | 119 | { |
f8f95702 AV |
120 | int fd = locate_fd(start, cloexec); |
121 | if (fd >= 0) | |
1da177e4 | 122 | fd_install(fd, file); |
f8f95702 | 123 | else |
1da177e4 | 124 | fput(file); |
1da177e4 LT |
125 | |
126 | return fd; | |
127 | } | |
128 | ||
129 | asmlinkage long sys_dup2(unsigned int oldfd, unsigned int newfd) | |
130 | { | |
131 | int err = -EBADF; | |
132 | struct file * file, *tofree; | |
133 | struct files_struct * files = current->files; | |
badf1662 | 134 | struct fdtable *fdt; |
1da177e4 LT |
135 | |
136 | spin_lock(&files->file_lock); | |
137 | if (!(file = fcheck(oldfd))) | |
138 | goto out_unlock; | |
139 | err = newfd; | |
140 | if (newfd == oldfd) | |
141 | goto out_unlock; | |
142 | err = -EBADF; | |
143 | if (newfd >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur) | |
144 | goto out_unlock; | |
145 | get_file(file); /* We are now finished with oldfd */ | |
146 | ||
147 | err = expand_files(files, newfd); | |
148 | if (err < 0) | |
149 | goto out_fput; | |
150 | ||
151 | /* To avoid races with open() and dup(), we will mark the fd as | |
152 | * in-use in the open-file bitmap throughout the entire dup2() | |
153 | * process. This is quite safe: do_close() uses the fd array | |
154 | * entry, not the bitmap, to decide what work needs to be | |
155 | * done. --sct */ | |
156 | /* Doesn't work. open() might be there first. --AV */ | |
157 | ||
158 | /* Yes. It's a race. In user space. Nothing sane to do */ | |
159 | err = -EBUSY; | |
badf1662 DS |
160 | fdt = files_fdtable(files); |
161 | tofree = fdt->fd[newfd]; | |
162 | if (!tofree && FD_ISSET(newfd, fdt->open_fds)) | |
1da177e4 LT |
163 | goto out_fput; |
164 | ||
ab2af1f5 | 165 | rcu_assign_pointer(fdt->fd[newfd], file); |
badf1662 DS |
166 | FD_SET(newfd, fdt->open_fds); |
167 | FD_CLR(newfd, fdt->close_on_exec); | |
1da177e4 LT |
168 | spin_unlock(&files->file_lock); |
169 | ||
170 | if (tofree) | |
171 | filp_close(tofree, files); | |
172 | err = newfd; | |
173 | out: | |
174 | return err; | |
175 | out_unlock: | |
176 | spin_unlock(&files->file_lock); | |
177 | goto out; | |
178 | ||
179 | out_fput: | |
180 | spin_unlock(&files->file_lock); | |
181 | fput(file); | |
182 | goto out; | |
183 | } | |
184 | ||
185 | asmlinkage long sys_dup(unsigned int fildes) | |
186 | { | |
187 | int ret = -EBADF; | |
188 | struct file * file = fget(fildes); | |
189 | ||
190 | if (file) | |
22d2b35b | 191 | ret = dupfd(file, 0, 0); |
1da177e4 LT |
192 | return ret; |
193 | } | |
194 | ||
195 | #define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | FASYNC | O_DIRECT | O_NOATIME) | |
196 | ||
197 | static int setfl(int fd, struct file * filp, unsigned long arg) | |
198 | { | |
0f7fc9e4 | 199 | struct inode * inode = filp->f_path.dentry->d_inode; |
1da177e4 LT |
200 | int error = 0; |
201 | ||
7d95c8f2 | 202 | /* |
203 | * O_APPEND cannot be cleared if the file is marked as append-only | |
204 | * and the file is open for write. | |
205 | */ | |
206 | if (((arg ^ filp->f_flags) & O_APPEND) && IS_APPEND(inode)) | |
1da177e4 LT |
207 | return -EPERM; |
208 | ||
209 | /* O_NOATIME can only be set by the owner or superuser */ | |
210 | if ((arg & O_NOATIME) && !(filp->f_flags & O_NOATIME)) | |
3bd858ab | 211 | if (!is_owner_or_cap(inode)) |
1da177e4 LT |
212 | return -EPERM; |
213 | ||
214 | /* required for strict SunOS emulation */ | |
215 | if (O_NONBLOCK != O_NDELAY) | |
216 | if (arg & O_NDELAY) | |
217 | arg |= O_NONBLOCK; | |
218 | ||
219 | if (arg & O_DIRECT) { | |
220 | if (!filp->f_mapping || !filp->f_mapping->a_ops || | |
221 | !filp->f_mapping->a_ops->direct_IO) | |
222 | return -EINVAL; | |
223 | } | |
224 | ||
225 | if (filp->f_op && filp->f_op->check_flags) | |
226 | error = filp->f_op->check_flags(arg); | |
227 | if (error) | |
228 | return error; | |
229 | ||
230 | lock_kernel(); | |
231 | if ((arg ^ filp->f_flags) & FASYNC) { | |
232 | if (filp->f_op && filp->f_op->fasync) { | |
233 | error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0); | |
234 | if (error < 0) | |
235 | goto out; | |
236 | } | |
237 | } | |
238 | ||
239 | filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK); | |
240 | out: | |
241 | unlock_kernel(); | |
242 | return error; | |
243 | } | |
244 | ||
609d7fa9 | 245 | static void f_modown(struct file *filp, struct pid *pid, enum pid_type type, |
1da177e4 LT |
246 | uid_t uid, uid_t euid, int force) |
247 | { | |
248 | write_lock_irq(&filp->f_owner.lock); | |
249 | if (force || !filp->f_owner.pid) { | |
609d7fa9 EB |
250 | put_pid(filp->f_owner.pid); |
251 | filp->f_owner.pid = get_pid(pid); | |
252 | filp->f_owner.pid_type = type; | |
1da177e4 LT |
253 | filp->f_owner.uid = uid; |
254 | filp->f_owner.euid = euid; | |
255 | } | |
256 | write_unlock_irq(&filp->f_owner.lock); | |
257 | } | |
258 | ||
609d7fa9 EB |
259 | int __f_setown(struct file *filp, struct pid *pid, enum pid_type type, |
260 | int force) | |
1da177e4 LT |
261 | { |
262 | int err; | |
263 | ||
264 | err = security_file_set_fowner(filp); | |
265 | if (err) | |
266 | return err; | |
267 | ||
609d7fa9 | 268 | f_modown(filp, pid, type, current->uid, current->euid, force); |
1da177e4 LT |
269 | return 0; |
270 | } | |
609d7fa9 | 271 | EXPORT_SYMBOL(__f_setown); |
1da177e4 | 272 | |
609d7fa9 EB |
273 | int f_setown(struct file *filp, unsigned long arg, int force) |
274 | { | |
275 | enum pid_type type; | |
276 | struct pid *pid; | |
277 | int who = arg; | |
278 | int result; | |
279 | type = PIDTYPE_PID; | |
280 | if (who < 0) { | |
281 | type = PIDTYPE_PGID; | |
282 | who = -who; | |
283 | } | |
284 | rcu_read_lock(); | |
b488893a | 285 | pid = find_vpid(who); |
609d7fa9 EB |
286 | result = __f_setown(filp, pid, type, force); |
287 | rcu_read_unlock(); | |
288 | return result; | |
289 | } | |
1da177e4 LT |
290 | EXPORT_SYMBOL(f_setown); |
291 | ||
292 | void f_delown(struct file *filp) | |
293 | { | |
609d7fa9 EB |
294 | f_modown(filp, NULL, PIDTYPE_PID, 0, 0, 1); |
295 | } | |
296 | ||
297 | pid_t f_getown(struct file *filp) | |
298 | { | |
299 | pid_t pid; | |
43fa1adb | 300 | read_lock(&filp->f_owner.lock); |
6c5f3e7b | 301 | pid = pid_vnr(filp->f_owner.pid); |
609d7fa9 EB |
302 | if (filp->f_owner.pid_type == PIDTYPE_PGID) |
303 | pid = -pid; | |
43fa1adb | 304 | read_unlock(&filp->f_owner.lock); |
609d7fa9 | 305 | return pid; |
1da177e4 LT |
306 | } |
307 | ||
308 | static long do_fcntl(int fd, unsigned int cmd, unsigned long arg, | |
309 | struct file *filp) | |
310 | { | |
311 | long err = -EINVAL; | |
312 | ||
313 | switch (cmd) { | |
314 | case F_DUPFD: | |
22d2b35b | 315 | case F_DUPFD_CLOEXEC: |
1da177e4 | 316 | get_file(filp); |
22d2b35b | 317 | err = dupfd(filp, arg, cmd == F_DUPFD_CLOEXEC); |
1da177e4 LT |
318 | break; |
319 | case F_GETFD: | |
320 | err = get_close_on_exec(fd) ? FD_CLOEXEC : 0; | |
321 | break; | |
322 | case F_SETFD: | |
323 | err = 0; | |
324 | set_close_on_exec(fd, arg & FD_CLOEXEC); | |
325 | break; | |
326 | case F_GETFL: | |
327 | err = filp->f_flags; | |
328 | break; | |
329 | case F_SETFL: | |
330 | err = setfl(fd, filp, arg); | |
331 | break; | |
332 | case F_GETLK: | |
333 | err = fcntl_getlk(filp, (struct flock __user *) arg); | |
334 | break; | |
335 | case F_SETLK: | |
336 | case F_SETLKW: | |
c293621b | 337 | err = fcntl_setlk(fd, filp, cmd, (struct flock __user *) arg); |
1da177e4 LT |
338 | break; |
339 | case F_GETOWN: | |
340 | /* | |
341 | * XXX If f_owner is a process group, the | |
342 | * negative return value will get converted | |
343 | * into an error. Oops. If we keep the | |
344 | * current syscall conventions, the only way | |
345 | * to fix this will be in libc. | |
346 | */ | |
609d7fa9 | 347 | err = f_getown(filp); |
1da177e4 LT |
348 | force_successful_syscall_return(); |
349 | break; | |
350 | case F_SETOWN: | |
351 | err = f_setown(filp, arg, 1); | |
352 | break; | |
353 | case F_GETSIG: | |
354 | err = filp->f_owner.signum; | |
355 | break; | |
356 | case F_SETSIG: | |
357 | /* arg == 0 restores default behaviour. */ | |
7ed20e1a | 358 | if (!valid_signal(arg)) { |
1da177e4 LT |
359 | break; |
360 | } | |
361 | err = 0; | |
362 | filp->f_owner.signum = arg; | |
363 | break; | |
364 | case F_GETLEASE: | |
365 | err = fcntl_getlease(filp); | |
366 | break; | |
367 | case F_SETLEASE: | |
368 | err = fcntl_setlease(fd, filp, arg); | |
369 | break; | |
370 | case F_NOTIFY: | |
371 | err = fcntl_dirnotify(fd, filp, arg); | |
372 | break; | |
373 | default: | |
374 | break; | |
375 | } | |
376 | return err; | |
377 | } | |
378 | ||
379 | asmlinkage long sys_fcntl(unsigned int fd, unsigned int cmd, unsigned long arg) | |
380 | { | |
381 | struct file *filp; | |
382 | long err = -EBADF; | |
383 | ||
384 | filp = fget(fd); | |
385 | if (!filp) | |
386 | goto out; | |
387 | ||
388 | err = security_file_fcntl(filp, cmd, arg); | |
389 | if (err) { | |
390 | fput(filp); | |
391 | return err; | |
392 | } | |
393 | ||
394 | err = do_fcntl(fd, cmd, arg, filp); | |
395 | ||
396 | fput(filp); | |
397 | out: | |
398 | return err; | |
399 | } | |
400 | ||
401 | #if BITS_PER_LONG == 32 | |
402 | asmlinkage long sys_fcntl64(unsigned int fd, unsigned int cmd, unsigned long arg) | |
403 | { | |
404 | struct file * filp; | |
405 | long err; | |
406 | ||
407 | err = -EBADF; | |
408 | filp = fget(fd); | |
409 | if (!filp) | |
410 | goto out; | |
411 | ||
412 | err = security_file_fcntl(filp, cmd, arg); | |
413 | if (err) { | |
414 | fput(filp); | |
415 | return err; | |
416 | } | |
417 | err = -EBADF; | |
418 | ||
419 | switch (cmd) { | |
420 | case F_GETLK64: | |
421 | err = fcntl_getlk64(filp, (struct flock64 __user *) arg); | |
422 | break; | |
423 | case F_SETLK64: | |
424 | case F_SETLKW64: | |
c293621b PS |
425 | err = fcntl_setlk64(fd, filp, cmd, |
426 | (struct flock64 __user *) arg); | |
1da177e4 LT |
427 | break; |
428 | default: | |
429 | err = do_fcntl(fd, cmd, arg, filp); | |
430 | break; | |
431 | } | |
432 | fput(filp); | |
433 | out: | |
434 | return err; | |
435 | } | |
436 | #endif | |
437 | ||
438 | /* Table to convert sigio signal codes into poll band bitmaps */ | |
439 | ||
fa3536cc | 440 | static const long band_table[NSIGPOLL] = { |
1da177e4 LT |
441 | POLLIN | POLLRDNORM, /* POLL_IN */ |
442 | POLLOUT | POLLWRNORM | POLLWRBAND, /* POLL_OUT */ | |
443 | POLLIN | POLLRDNORM | POLLMSG, /* POLL_MSG */ | |
444 | POLLERR, /* POLL_ERR */ | |
445 | POLLPRI | POLLRDBAND, /* POLL_PRI */ | |
446 | POLLHUP | POLLERR /* POLL_HUP */ | |
447 | }; | |
448 | ||
449 | static inline int sigio_perm(struct task_struct *p, | |
450 | struct fown_struct *fown, int sig) | |
451 | { | |
452 | return (((fown->euid == 0) || | |
453 | (fown->euid == p->suid) || (fown->euid == p->uid) || | |
454 | (fown->uid == p->suid) || (fown->uid == p->uid)) && | |
455 | !security_file_send_sigiotask(p, fown, sig)); | |
456 | } | |
457 | ||
458 | static void send_sigio_to_task(struct task_struct *p, | |
459 | struct fown_struct *fown, | |
460 | int fd, | |
461 | int reason) | |
462 | { | |
463 | if (!sigio_perm(p, fown, fown->signum)) | |
464 | return; | |
465 | ||
466 | switch (fown->signum) { | |
467 | siginfo_t si; | |
468 | default: | |
469 | /* Queue a rt signal with the appropriate fd as its | |
470 | value. We use SI_SIGIO as the source, not | |
471 | SI_KERNEL, since kernel signals always get | |
472 | delivered even if we can't queue. Failure to | |
473 | queue in this case _should_ be reported; we fall | |
474 | back to SIGIO in that case. --sct */ | |
475 | si.si_signo = fown->signum; | |
476 | si.si_errno = 0; | |
477 | si.si_code = reason; | |
478 | /* Make sure we are called with one of the POLL_* | |
479 | reasons, otherwise we could leak kernel stack into | |
480 | userspace. */ | |
f6298aab | 481 | BUG_ON((reason & __SI_MASK) != __SI_POLL); |
1da177e4 LT |
482 | if (reason - POLL_IN >= NSIGPOLL) |
483 | si.si_band = ~0L; | |
484 | else | |
485 | si.si_band = band_table[reason - POLL_IN]; | |
486 | si.si_fd = fd; | |
850d6fbe | 487 | if (!group_send_sig_info(fown->signum, &si, p)) |
1da177e4 LT |
488 | break; |
489 | /* fall-through: fall back on the old plain SIGIO signal */ | |
490 | case 0: | |
850d6fbe | 491 | group_send_sig_info(SIGIO, SEND_SIG_PRIV, p); |
1da177e4 LT |
492 | } |
493 | } | |
494 | ||
495 | void send_sigio(struct fown_struct *fown, int fd, int band) | |
496 | { | |
497 | struct task_struct *p; | |
609d7fa9 EB |
498 | enum pid_type type; |
499 | struct pid *pid; | |
1da177e4 LT |
500 | |
501 | read_lock(&fown->lock); | |
609d7fa9 | 502 | type = fown->pid_type; |
1da177e4 LT |
503 | pid = fown->pid; |
504 | if (!pid) | |
505 | goto out_unlock_fown; | |
506 | ||
507 | read_lock(&tasklist_lock); | |
609d7fa9 EB |
508 | do_each_pid_task(pid, type, p) { |
509 | send_sigio_to_task(p, fown, fd, band); | |
510 | } while_each_pid_task(pid, type, p); | |
1da177e4 LT |
511 | read_unlock(&tasklist_lock); |
512 | out_unlock_fown: | |
513 | read_unlock(&fown->lock); | |
514 | } | |
515 | ||
516 | static void send_sigurg_to_task(struct task_struct *p, | |
517 | struct fown_struct *fown) | |
518 | { | |
519 | if (sigio_perm(p, fown, SIGURG)) | |
850d6fbe | 520 | group_send_sig_info(SIGURG, SEND_SIG_PRIV, p); |
1da177e4 LT |
521 | } |
522 | ||
523 | int send_sigurg(struct fown_struct *fown) | |
524 | { | |
525 | struct task_struct *p; | |
609d7fa9 EB |
526 | enum pid_type type; |
527 | struct pid *pid; | |
528 | int ret = 0; | |
1da177e4 LT |
529 | |
530 | read_lock(&fown->lock); | |
609d7fa9 | 531 | type = fown->pid_type; |
1da177e4 LT |
532 | pid = fown->pid; |
533 | if (!pid) | |
534 | goto out_unlock_fown; | |
535 | ||
536 | ret = 1; | |
537 | ||
538 | read_lock(&tasklist_lock); | |
609d7fa9 EB |
539 | do_each_pid_task(pid, type, p) { |
540 | send_sigurg_to_task(p, fown); | |
541 | } while_each_pid_task(pid, type, p); | |
1da177e4 LT |
542 | read_unlock(&tasklist_lock); |
543 | out_unlock_fown: | |
544 | read_unlock(&fown->lock); | |
545 | return ret; | |
546 | } | |
547 | ||
548 | static DEFINE_RWLOCK(fasync_lock); | |
e18b890b | 549 | static struct kmem_cache *fasync_cache __read_mostly; |
1da177e4 LT |
550 | |
551 | /* | |
552 | * fasync_helper() is used by some character device drivers (mainly mice) | |
553 | * to set up the fasync queue. It returns negative on error, 0 if it did | |
554 | * no changes and positive if it added/deleted the entry. | |
555 | */ | |
556 | int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp) | |
557 | { | |
558 | struct fasync_struct *fa, **fp; | |
559 | struct fasync_struct *new = NULL; | |
560 | int result = 0; | |
561 | ||
562 | if (on) { | |
e94b1766 | 563 | new = kmem_cache_alloc(fasync_cache, GFP_KERNEL); |
1da177e4 LT |
564 | if (!new) |
565 | return -ENOMEM; | |
566 | } | |
567 | write_lock_irq(&fasync_lock); | |
568 | for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) { | |
569 | if (fa->fa_file == filp) { | |
570 | if(on) { | |
571 | fa->fa_fd = fd; | |
572 | kmem_cache_free(fasync_cache, new); | |
573 | } else { | |
574 | *fp = fa->fa_next; | |
575 | kmem_cache_free(fasync_cache, fa); | |
576 | result = 1; | |
577 | } | |
578 | goto out; | |
579 | } | |
580 | } | |
581 | ||
582 | if (on) { | |
583 | new->magic = FASYNC_MAGIC; | |
584 | new->fa_file = filp; | |
585 | new->fa_fd = fd; | |
586 | new->fa_next = *fapp; | |
587 | *fapp = new; | |
588 | result = 1; | |
589 | } | |
590 | out: | |
591 | write_unlock_irq(&fasync_lock); | |
592 | return result; | |
593 | } | |
594 | ||
595 | EXPORT_SYMBOL(fasync_helper); | |
596 | ||
597 | void __kill_fasync(struct fasync_struct *fa, int sig, int band) | |
598 | { | |
599 | while (fa) { | |
600 | struct fown_struct * fown; | |
601 | if (fa->magic != FASYNC_MAGIC) { | |
602 | printk(KERN_ERR "kill_fasync: bad magic number in " | |
603 | "fasync_struct!\n"); | |
604 | return; | |
605 | } | |
606 | fown = &fa->fa_file->f_owner; | |
607 | /* Don't send SIGURG to processes which have not set a | |
608 | queued signum: SIGURG has its own default signalling | |
609 | mechanism. */ | |
610 | if (!(sig == SIGURG && fown->signum == 0)) | |
611 | send_sigio(fown, fa->fa_fd, band); | |
612 | fa = fa->fa_next; | |
613 | } | |
614 | } | |
615 | ||
616 | EXPORT_SYMBOL(__kill_fasync); | |
617 | ||
618 | void kill_fasync(struct fasync_struct **fp, int sig, int band) | |
619 | { | |
620 | /* First a quick test without locking: usually | |
621 | * the list is empty. | |
622 | */ | |
623 | if (*fp) { | |
624 | read_lock(&fasync_lock); | |
625 | /* reread *fp after obtaining the lock */ | |
626 | __kill_fasync(*fp, sig, band); | |
627 | read_unlock(&fasync_lock); | |
628 | } | |
629 | } | |
630 | EXPORT_SYMBOL(kill_fasync); | |
631 | ||
632 | static int __init fasync_init(void) | |
633 | { | |
634 | fasync_cache = kmem_cache_create("fasync_cache", | |
20c2df83 | 635 | sizeof(struct fasync_struct), 0, SLAB_PANIC, NULL); |
1da177e4 LT |
636 | return 0; |
637 | } | |
638 | ||
639 | module_init(fasync_init) |