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> |
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 | ||
27 | void fastcall set_close_on_exec(unsigned int fd, int flag) | |
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 | ||
52 | /* | |
53 | * locate_fd finds a free file descriptor in the open_fds fdset, | |
54 | * expanding the fd arrays if necessary. Must be called with the | |
55 | * file_lock held for write. | |
56 | */ | |
57 | ||
58 | static int locate_fd(struct files_struct *files, | |
59 | struct file *file, unsigned int orig_start) | |
60 | { | |
61 | unsigned int newfd; | |
62 | unsigned int start; | |
63 | int error; | |
badf1662 | 64 | struct fdtable *fdt; |
1da177e4 LT |
65 | |
66 | error = -EINVAL; | |
67 | if (orig_start >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur) | |
68 | goto out; | |
69 | ||
70 | repeat: | |
ab2af1f5 | 71 | fdt = files_fdtable(files); |
1da177e4 LT |
72 | /* |
73 | * Someone might have closed fd's in the range | |
badf1662 | 74 | * orig_start..fdt->next_fd |
1da177e4 LT |
75 | */ |
76 | start = orig_start; | |
0c9e63fd ED |
77 | if (start < files->next_fd) |
78 | start = files->next_fd; | |
1da177e4 LT |
79 | |
80 | newfd = start; | |
bbea9f69 | 81 | if (start < fdt->max_fds) |
badf1662 | 82 | newfd = find_next_zero_bit(fdt->open_fds->fds_bits, |
bbea9f69 | 83 | fdt->max_fds, start); |
1da177e4 LT |
84 | |
85 | error = -EMFILE; | |
86 | if (newfd >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur) | |
87 | goto out; | |
88 | ||
89 | error = expand_files(files, newfd); | |
90 | if (error < 0) | |
91 | goto out; | |
92 | ||
93 | /* | |
94 | * If we needed to expand the fs array we | |
95 | * might have blocked - try again. | |
96 | */ | |
97 | if (error) | |
98 | goto repeat; | |
99 | ||
ab2af1f5 DS |
100 | /* |
101 | * We reacquired files_lock, so we are safe as long as | |
102 | * we reacquire the fdtable pointer and use it while holding | |
103 | * the lock, no one can free it during that time. | |
104 | */ | |
0c9e63fd ED |
105 | if (start <= files->next_fd) |
106 | files->next_fd = newfd + 1; | |
ab2af1f5 | 107 | |
1da177e4 LT |
108 | error = newfd; |
109 | ||
110 | out: | |
111 | return error; | |
112 | } | |
113 | ||
22d2b35b | 114 | static int dupfd(struct file *file, unsigned int start, int cloexec) |
1da177e4 LT |
115 | { |
116 | struct files_struct * files = current->files; | |
badf1662 | 117 | struct fdtable *fdt; |
1da177e4 LT |
118 | int fd; |
119 | ||
120 | spin_lock(&files->file_lock); | |
121 | fd = locate_fd(files, file, start); | |
122 | if (fd >= 0) { | |
badf1662 DS |
123 | /* locate_fd() may have expanded fdtable, load the ptr */ |
124 | fdt = files_fdtable(files); | |
125 | FD_SET(fd, fdt->open_fds); | |
22d2b35b UD |
126 | if (cloexec) |
127 | FD_SET(fd, fdt->close_on_exec); | |
128 | else | |
129 | FD_CLR(fd, fdt->close_on_exec); | |
1da177e4 LT |
130 | spin_unlock(&files->file_lock); |
131 | fd_install(fd, file); | |
132 | } else { | |
133 | spin_unlock(&files->file_lock); | |
134 | fput(file); | |
135 | } | |
136 | ||
137 | return fd; | |
138 | } | |
139 | ||
140 | asmlinkage long sys_dup2(unsigned int oldfd, unsigned int newfd) | |
141 | { | |
142 | int err = -EBADF; | |
143 | struct file * file, *tofree; | |
144 | struct files_struct * files = current->files; | |
badf1662 | 145 | struct fdtable *fdt; |
1da177e4 LT |
146 | |
147 | spin_lock(&files->file_lock); | |
148 | if (!(file = fcheck(oldfd))) | |
149 | goto out_unlock; | |
150 | err = newfd; | |
151 | if (newfd == oldfd) | |
152 | goto out_unlock; | |
153 | err = -EBADF; | |
154 | if (newfd >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur) | |
155 | goto out_unlock; | |
156 | get_file(file); /* We are now finished with oldfd */ | |
157 | ||
158 | err = expand_files(files, newfd); | |
159 | if (err < 0) | |
160 | goto out_fput; | |
161 | ||
162 | /* To avoid races with open() and dup(), we will mark the fd as | |
163 | * in-use in the open-file bitmap throughout the entire dup2() | |
164 | * process. This is quite safe: do_close() uses the fd array | |
165 | * entry, not the bitmap, to decide what work needs to be | |
166 | * done. --sct */ | |
167 | /* Doesn't work. open() might be there first. --AV */ | |
168 | ||
169 | /* Yes. It's a race. In user space. Nothing sane to do */ | |
170 | err = -EBUSY; | |
badf1662 DS |
171 | fdt = files_fdtable(files); |
172 | tofree = fdt->fd[newfd]; | |
173 | if (!tofree && FD_ISSET(newfd, fdt->open_fds)) | |
1da177e4 LT |
174 | goto out_fput; |
175 | ||
ab2af1f5 | 176 | rcu_assign_pointer(fdt->fd[newfd], file); |
badf1662 DS |
177 | FD_SET(newfd, fdt->open_fds); |
178 | FD_CLR(newfd, fdt->close_on_exec); | |
1da177e4 LT |
179 | spin_unlock(&files->file_lock); |
180 | ||
181 | if (tofree) | |
182 | filp_close(tofree, files); | |
183 | err = newfd; | |
184 | out: | |
185 | return err; | |
186 | out_unlock: | |
187 | spin_unlock(&files->file_lock); | |
188 | goto out; | |
189 | ||
190 | out_fput: | |
191 | spin_unlock(&files->file_lock); | |
192 | fput(file); | |
193 | goto out; | |
194 | } | |
195 | ||
196 | asmlinkage long sys_dup(unsigned int fildes) | |
197 | { | |
198 | int ret = -EBADF; | |
199 | struct file * file = fget(fildes); | |
200 | ||
201 | if (file) | |
22d2b35b | 202 | ret = dupfd(file, 0, 0); |
1da177e4 LT |
203 | return ret; |
204 | } | |
205 | ||
206 | #define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | FASYNC | O_DIRECT | O_NOATIME) | |
207 | ||
208 | static int setfl(int fd, struct file * filp, unsigned long arg) | |
209 | { | |
0f7fc9e4 | 210 | struct inode * inode = filp->f_path.dentry->d_inode; |
1da177e4 LT |
211 | int error = 0; |
212 | ||
7d95c8f2 | 213 | /* |
214 | * O_APPEND cannot be cleared if the file is marked as append-only | |
215 | * and the file is open for write. | |
216 | */ | |
217 | if (((arg ^ filp->f_flags) & O_APPEND) && IS_APPEND(inode)) | |
1da177e4 LT |
218 | return -EPERM; |
219 | ||
220 | /* O_NOATIME can only be set by the owner or superuser */ | |
221 | if ((arg & O_NOATIME) && !(filp->f_flags & O_NOATIME)) | |
3bd858ab | 222 | if (!is_owner_or_cap(inode)) |
1da177e4 LT |
223 | return -EPERM; |
224 | ||
225 | /* required for strict SunOS emulation */ | |
226 | if (O_NONBLOCK != O_NDELAY) | |
227 | if (arg & O_NDELAY) | |
228 | arg |= O_NONBLOCK; | |
229 | ||
230 | if (arg & O_DIRECT) { | |
231 | if (!filp->f_mapping || !filp->f_mapping->a_ops || | |
232 | !filp->f_mapping->a_ops->direct_IO) | |
233 | return -EINVAL; | |
234 | } | |
235 | ||
236 | if (filp->f_op && filp->f_op->check_flags) | |
237 | error = filp->f_op->check_flags(arg); | |
238 | if (error) | |
239 | return error; | |
240 | ||
241 | lock_kernel(); | |
242 | if ((arg ^ filp->f_flags) & FASYNC) { | |
243 | if (filp->f_op && filp->f_op->fasync) { | |
244 | error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0); | |
245 | if (error < 0) | |
246 | goto out; | |
247 | } | |
248 | } | |
249 | ||
250 | filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK); | |
251 | out: | |
252 | unlock_kernel(); | |
253 | return error; | |
254 | } | |
255 | ||
609d7fa9 | 256 | static void f_modown(struct file *filp, struct pid *pid, enum pid_type type, |
1da177e4 LT |
257 | uid_t uid, uid_t euid, int force) |
258 | { | |
259 | write_lock_irq(&filp->f_owner.lock); | |
260 | if (force || !filp->f_owner.pid) { | |
609d7fa9 EB |
261 | put_pid(filp->f_owner.pid); |
262 | filp->f_owner.pid = get_pid(pid); | |
263 | filp->f_owner.pid_type = type; | |
1da177e4 LT |
264 | filp->f_owner.uid = uid; |
265 | filp->f_owner.euid = euid; | |
266 | } | |
267 | write_unlock_irq(&filp->f_owner.lock); | |
268 | } | |
269 | ||
609d7fa9 EB |
270 | int __f_setown(struct file *filp, struct pid *pid, enum pid_type type, |
271 | int force) | |
1da177e4 LT |
272 | { |
273 | int err; | |
274 | ||
275 | err = security_file_set_fowner(filp); | |
276 | if (err) | |
277 | return err; | |
278 | ||
609d7fa9 | 279 | f_modown(filp, pid, type, current->uid, current->euid, force); |
1da177e4 LT |
280 | return 0; |
281 | } | |
609d7fa9 | 282 | EXPORT_SYMBOL(__f_setown); |
1da177e4 | 283 | |
609d7fa9 EB |
284 | int f_setown(struct file *filp, unsigned long arg, int force) |
285 | { | |
286 | enum pid_type type; | |
287 | struct pid *pid; | |
288 | int who = arg; | |
289 | int result; | |
290 | type = PIDTYPE_PID; | |
291 | if (who < 0) { | |
292 | type = PIDTYPE_PGID; | |
293 | who = -who; | |
294 | } | |
295 | rcu_read_lock(); | |
b488893a | 296 | pid = find_vpid(who); |
609d7fa9 EB |
297 | result = __f_setown(filp, pid, type, force); |
298 | rcu_read_unlock(); | |
299 | return result; | |
300 | } | |
1da177e4 LT |
301 | EXPORT_SYMBOL(f_setown); |
302 | ||
303 | void f_delown(struct file *filp) | |
304 | { | |
609d7fa9 EB |
305 | f_modown(filp, NULL, PIDTYPE_PID, 0, 0, 1); |
306 | } | |
307 | ||
308 | pid_t f_getown(struct file *filp) | |
309 | { | |
310 | pid_t pid; | |
43fa1adb | 311 | read_lock(&filp->f_owner.lock); |
b488893a | 312 | pid = pid_nr_ns(filp->f_owner.pid, current->nsproxy->pid_ns); |
609d7fa9 EB |
313 | if (filp->f_owner.pid_type == PIDTYPE_PGID) |
314 | pid = -pid; | |
43fa1adb | 315 | read_unlock(&filp->f_owner.lock); |
609d7fa9 | 316 | return pid; |
1da177e4 LT |
317 | } |
318 | ||
319 | static long do_fcntl(int fd, unsigned int cmd, unsigned long arg, | |
320 | struct file *filp) | |
321 | { | |
322 | long err = -EINVAL; | |
323 | ||
324 | switch (cmd) { | |
325 | case F_DUPFD: | |
22d2b35b | 326 | case F_DUPFD_CLOEXEC: |
1da177e4 | 327 | get_file(filp); |
22d2b35b | 328 | err = dupfd(filp, arg, cmd == F_DUPFD_CLOEXEC); |
1da177e4 LT |
329 | break; |
330 | case F_GETFD: | |
331 | err = get_close_on_exec(fd) ? FD_CLOEXEC : 0; | |
332 | break; | |
333 | case F_SETFD: | |
334 | err = 0; | |
335 | set_close_on_exec(fd, arg & FD_CLOEXEC); | |
336 | break; | |
337 | case F_GETFL: | |
338 | err = filp->f_flags; | |
339 | break; | |
340 | case F_SETFL: | |
341 | err = setfl(fd, filp, arg); | |
342 | break; | |
343 | case F_GETLK: | |
344 | err = fcntl_getlk(filp, (struct flock __user *) arg); | |
345 | break; | |
346 | case F_SETLK: | |
347 | case F_SETLKW: | |
c293621b | 348 | err = fcntl_setlk(fd, filp, cmd, (struct flock __user *) arg); |
1da177e4 LT |
349 | break; |
350 | case F_GETOWN: | |
351 | /* | |
352 | * XXX If f_owner is a process group, the | |
353 | * negative return value will get converted | |
354 | * into an error. Oops. If we keep the | |
355 | * current syscall conventions, the only way | |
356 | * to fix this will be in libc. | |
357 | */ | |
609d7fa9 | 358 | err = f_getown(filp); |
1da177e4 LT |
359 | force_successful_syscall_return(); |
360 | break; | |
361 | case F_SETOWN: | |
362 | err = f_setown(filp, arg, 1); | |
363 | break; | |
364 | case F_GETSIG: | |
365 | err = filp->f_owner.signum; | |
366 | break; | |
367 | case F_SETSIG: | |
368 | /* arg == 0 restores default behaviour. */ | |
7ed20e1a | 369 | if (!valid_signal(arg)) { |
1da177e4 LT |
370 | break; |
371 | } | |
372 | err = 0; | |
373 | filp->f_owner.signum = arg; | |
374 | break; | |
375 | case F_GETLEASE: | |
376 | err = fcntl_getlease(filp); | |
377 | break; | |
378 | case F_SETLEASE: | |
379 | err = fcntl_setlease(fd, filp, arg); | |
380 | break; | |
381 | case F_NOTIFY: | |
382 | err = fcntl_dirnotify(fd, filp, arg); | |
383 | break; | |
384 | default: | |
385 | break; | |
386 | } | |
387 | return err; | |
388 | } | |
389 | ||
390 | asmlinkage long sys_fcntl(unsigned int fd, unsigned int cmd, unsigned long arg) | |
391 | { | |
392 | struct file *filp; | |
393 | long err = -EBADF; | |
394 | ||
395 | filp = fget(fd); | |
396 | if (!filp) | |
397 | goto out; | |
398 | ||
399 | err = security_file_fcntl(filp, cmd, arg); | |
400 | if (err) { | |
401 | fput(filp); | |
402 | return err; | |
403 | } | |
404 | ||
405 | err = do_fcntl(fd, cmd, arg, filp); | |
406 | ||
407 | fput(filp); | |
408 | out: | |
409 | return err; | |
410 | } | |
411 | ||
412 | #if BITS_PER_LONG == 32 | |
413 | asmlinkage long sys_fcntl64(unsigned int fd, unsigned int cmd, unsigned long arg) | |
414 | { | |
415 | struct file * filp; | |
416 | long err; | |
417 | ||
418 | err = -EBADF; | |
419 | filp = fget(fd); | |
420 | if (!filp) | |
421 | goto out; | |
422 | ||
423 | err = security_file_fcntl(filp, cmd, arg); | |
424 | if (err) { | |
425 | fput(filp); | |
426 | return err; | |
427 | } | |
428 | err = -EBADF; | |
429 | ||
430 | switch (cmd) { | |
431 | case F_GETLK64: | |
432 | err = fcntl_getlk64(filp, (struct flock64 __user *) arg); | |
433 | break; | |
434 | case F_SETLK64: | |
435 | case F_SETLKW64: | |
c293621b PS |
436 | err = fcntl_setlk64(fd, filp, cmd, |
437 | (struct flock64 __user *) arg); | |
1da177e4 LT |
438 | break; |
439 | default: | |
440 | err = do_fcntl(fd, cmd, arg, filp); | |
441 | break; | |
442 | } | |
443 | fput(filp); | |
444 | out: | |
445 | return err; | |
446 | } | |
447 | #endif | |
448 | ||
449 | /* Table to convert sigio signal codes into poll band bitmaps */ | |
450 | ||
fa3536cc | 451 | static const long band_table[NSIGPOLL] = { |
1da177e4 LT |
452 | POLLIN | POLLRDNORM, /* POLL_IN */ |
453 | POLLOUT | POLLWRNORM | POLLWRBAND, /* POLL_OUT */ | |
454 | POLLIN | POLLRDNORM | POLLMSG, /* POLL_MSG */ | |
455 | POLLERR, /* POLL_ERR */ | |
456 | POLLPRI | POLLRDBAND, /* POLL_PRI */ | |
457 | POLLHUP | POLLERR /* POLL_HUP */ | |
458 | }; | |
459 | ||
460 | static inline int sigio_perm(struct task_struct *p, | |
461 | struct fown_struct *fown, int sig) | |
462 | { | |
463 | return (((fown->euid == 0) || | |
464 | (fown->euid == p->suid) || (fown->euid == p->uid) || | |
465 | (fown->uid == p->suid) || (fown->uid == p->uid)) && | |
466 | !security_file_send_sigiotask(p, fown, sig)); | |
467 | } | |
468 | ||
469 | static void send_sigio_to_task(struct task_struct *p, | |
470 | struct fown_struct *fown, | |
471 | int fd, | |
472 | int reason) | |
473 | { | |
474 | if (!sigio_perm(p, fown, fown->signum)) | |
475 | return; | |
476 | ||
477 | switch (fown->signum) { | |
478 | siginfo_t si; | |
479 | default: | |
480 | /* Queue a rt signal with the appropriate fd as its | |
481 | value. We use SI_SIGIO as the source, not | |
482 | SI_KERNEL, since kernel signals always get | |
483 | delivered even if we can't queue. Failure to | |
484 | queue in this case _should_ be reported; we fall | |
485 | back to SIGIO in that case. --sct */ | |
486 | si.si_signo = fown->signum; | |
487 | si.si_errno = 0; | |
488 | si.si_code = reason; | |
489 | /* Make sure we are called with one of the POLL_* | |
490 | reasons, otherwise we could leak kernel stack into | |
491 | userspace. */ | |
f6298aab | 492 | BUG_ON((reason & __SI_MASK) != __SI_POLL); |
1da177e4 LT |
493 | if (reason - POLL_IN >= NSIGPOLL) |
494 | si.si_band = ~0L; | |
495 | else | |
496 | si.si_band = band_table[reason - POLL_IN]; | |
497 | si.si_fd = fd; | |
850d6fbe | 498 | if (!group_send_sig_info(fown->signum, &si, p)) |
1da177e4 LT |
499 | break; |
500 | /* fall-through: fall back on the old plain SIGIO signal */ | |
501 | case 0: | |
850d6fbe | 502 | group_send_sig_info(SIGIO, SEND_SIG_PRIV, p); |
1da177e4 LT |
503 | } |
504 | } | |
505 | ||
506 | void send_sigio(struct fown_struct *fown, int fd, int band) | |
507 | { | |
508 | struct task_struct *p; | |
609d7fa9 EB |
509 | enum pid_type type; |
510 | struct pid *pid; | |
1da177e4 LT |
511 | |
512 | read_lock(&fown->lock); | |
609d7fa9 | 513 | type = fown->pid_type; |
1da177e4 LT |
514 | pid = fown->pid; |
515 | if (!pid) | |
516 | goto out_unlock_fown; | |
517 | ||
518 | read_lock(&tasklist_lock); | |
609d7fa9 EB |
519 | do_each_pid_task(pid, type, p) { |
520 | send_sigio_to_task(p, fown, fd, band); | |
521 | } while_each_pid_task(pid, type, p); | |
1da177e4 LT |
522 | read_unlock(&tasklist_lock); |
523 | out_unlock_fown: | |
524 | read_unlock(&fown->lock); | |
525 | } | |
526 | ||
527 | static void send_sigurg_to_task(struct task_struct *p, | |
528 | struct fown_struct *fown) | |
529 | { | |
530 | if (sigio_perm(p, fown, SIGURG)) | |
850d6fbe | 531 | group_send_sig_info(SIGURG, SEND_SIG_PRIV, p); |
1da177e4 LT |
532 | } |
533 | ||
534 | int send_sigurg(struct fown_struct *fown) | |
535 | { | |
536 | struct task_struct *p; | |
609d7fa9 EB |
537 | enum pid_type type; |
538 | struct pid *pid; | |
539 | int ret = 0; | |
1da177e4 LT |
540 | |
541 | read_lock(&fown->lock); | |
609d7fa9 | 542 | type = fown->pid_type; |
1da177e4 LT |
543 | pid = fown->pid; |
544 | if (!pid) | |
545 | goto out_unlock_fown; | |
546 | ||
547 | ret = 1; | |
548 | ||
549 | read_lock(&tasklist_lock); | |
609d7fa9 EB |
550 | do_each_pid_task(pid, type, p) { |
551 | send_sigurg_to_task(p, fown); | |
552 | } while_each_pid_task(pid, type, p); | |
1da177e4 LT |
553 | read_unlock(&tasklist_lock); |
554 | out_unlock_fown: | |
555 | read_unlock(&fown->lock); | |
556 | return ret; | |
557 | } | |
558 | ||
559 | static DEFINE_RWLOCK(fasync_lock); | |
e18b890b | 560 | static struct kmem_cache *fasync_cache __read_mostly; |
1da177e4 LT |
561 | |
562 | /* | |
563 | * fasync_helper() is used by some character device drivers (mainly mice) | |
564 | * to set up the fasync queue. It returns negative on error, 0 if it did | |
565 | * no changes and positive if it added/deleted the entry. | |
566 | */ | |
567 | int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp) | |
568 | { | |
569 | struct fasync_struct *fa, **fp; | |
570 | struct fasync_struct *new = NULL; | |
571 | int result = 0; | |
572 | ||
573 | if (on) { | |
e94b1766 | 574 | new = kmem_cache_alloc(fasync_cache, GFP_KERNEL); |
1da177e4 LT |
575 | if (!new) |
576 | return -ENOMEM; | |
577 | } | |
578 | write_lock_irq(&fasync_lock); | |
579 | for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) { | |
580 | if (fa->fa_file == filp) { | |
581 | if(on) { | |
582 | fa->fa_fd = fd; | |
583 | kmem_cache_free(fasync_cache, new); | |
584 | } else { | |
585 | *fp = fa->fa_next; | |
586 | kmem_cache_free(fasync_cache, fa); | |
587 | result = 1; | |
588 | } | |
589 | goto out; | |
590 | } | |
591 | } | |
592 | ||
593 | if (on) { | |
594 | new->magic = FASYNC_MAGIC; | |
595 | new->fa_file = filp; | |
596 | new->fa_fd = fd; | |
597 | new->fa_next = *fapp; | |
598 | *fapp = new; | |
599 | result = 1; | |
600 | } | |
601 | out: | |
602 | write_unlock_irq(&fasync_lock); | |
603 | return result; | |
604 | } | |
605 | ||
606 | EXPORT_SYMBOL(fasync_helper); | |
607 | ||
608 | void __kill_fasync(struct fasync_struct *fa, int sig, int band) | |
609 | { | |
610 | while (fa) { | |
611 | struct fown_struct * fown; | |
612 | if (fa->magic != FASYNC_MAGIC) { | |
613 | printk(KERN_ERR "kill_fasync: bad magic number in " | |
614 | "fasync_struct!\n"); | |
615 | return; | |
616 | } | |
617 | fown = &fa->fa_file->f_owner; | |
618 | /* Don't send SIGURG to processes which have not set a | |
619 | queued signum: SIGURG has its own default signalling | |
620 | mechanism. */ | |
621 | if (!(sig == SIGURG && fown->signum == 0)) | |
622 | send_sigio(fown, fa->fa_fd, band); | |
623 | fa = fa->fa_next; | |
624 | } | |
625 | } | |
626 | ||
627 | EXPORT_SYMBOL(__kill_fasync); | |
628 | ||
629 | void kill_fasync(struct fasync_struct **fp, int sig, int band) | |
630 | { | |
631 | /* First a quick test without locking: usually | |
632 | * the list is empty. | |
633 | */ | |
634 | if (*fp) { | |
635 | read_lock(&fasync_lock); | |
636 | /* reread *fp after obtaining the lock */ | |
637 | __kill_fasync(*fp, sig, band); | |
638 | read_unlock(&fasync_lock); | |
639 | } | |
640 | } | |
641 | EXPORT_SYMBOL(kill_fasync); | |
642 | ||
643 | static int __init fasync_init(void) | |
644 | { | |
645 | fasync_cache = kmem_cache_create("fasync_cache", | |
20c2df83 | 646 | sizeof(struct fasync_struct), 0, SLAB_PANIC, NULL); |
1da177e4 LT |
647 | return 0; |
648 | } | |
649 | ||
650 | module_init(fasync_init) |