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> | |
35f3d14d | 17 | #include <linux/pipe_fs_i.h> |
1da177e4 LT |
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> |
1d151c33 | 23 | #include <linux/user_namespace.h> |
1da177e4 LT |
24 | |
25 | #include <asm/poll.h> | |
26 | #include <asm/siginfo.h> | |
27 | #include <asm/uaccess.h> | |
28 | ||
76398425 | 29 | #define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | O_DIRECT | O_NOATIME) |
1da177e4 LT |
30 | |
31 | static int setfl(int fd, struct file * filp, unsigned long arg) | |
32 | { | |
496ad9aa | 33 | struct inode * inode = file_inode(filp); |
1da177e4 LT |
34 | int error = 0; |
35 | ||
7d95c8f2 | 36 | /* |
37 | * O_APPEND cannot be cleared if the file is marked as append-only | |
38 | * and the file is open for write. | |
39 | */ | |
40 | if (((arg ^ filp->f_flags) & O_APPEND) && IS_APPEND(inode)) | |
1da177e4 LT |
41 | return -EPERM; |
42 | ||
43 | /* O_NOATIME can only be set by the owner or superuser */ | |
44 | if ((arg & O_NOATIME) && !(filp->f_flags & O_NOATIME)) | |
2e149670 | 45 | if (!inode_owner_or_capable(inode)) |
1da177e4 LT |
46 | return -EPERM; |
47 | ||
48 | /* required for strict SunOS emulation */ | |
49 | if (O_NONBLOCK != O_NDELAY) | |
50 | if (arg & O_NDELAY) | |
51 | arg |= O_NONBLOCK; | |
52 | ||
53 | if (arg & O_DIRECT) { | |
54 | if (!filp->f_mapping || !filp->f_mapping->a_ops || | |
55 | !filp->f_mapping->a_ops->direct_IO) | |
56 | return -EINVAL; | |
57 | } | |
58 | ||
72c2d531 | 59 | if (filp->f_op->check_flags) |
1da177e4 LT |
60 | error = filp->f_op->check_flags(arg); |
61 | if (error) | |
62 | return error; | |
63 | ||
218d11a8 | 64 | /* |
76398425 | 65 | * ->fasync() is responsible for setting the FASYNC bit. |
218d11a8 | 66 | */ |
72c2d531 | 67 | if (((arg ^ filp->f_flags) & FASYNC) && filp->f_op->fasync) { |
76398425 JC |
68 | error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0); |
69 | if (error < 0) | |
70 | goto out; | |
60aa4924 JC |
71 | if (error > 0) |
72 | error = 0; | |
1da177e4 | 73 | } |
db1dd4d3 | 74 | spin_lock(&filp->f_lock); |
1da177e4 | 75 | filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK); |
db1dd4d3 | 76 | spin_unlock(&filp->f_lock); |
76398425 | 77 | |
1da177e4 | 78 | out: |
1da177e4 LT |
79 | return error; |
80 | } | |
81 | ||
609d7fa9 | 82 | static void f_modown(struct file *filp, struct pid *pid, enum pid_type type, |
2f38d70f | 83 | int force) |
1da177e4 | 84 | { |
80e1e823 | 85 | write_lock_irq(&filp->f_owner.lock); |
1da177e4 | 86 | if (force || !filp->f_owner.pid) { |
609d7fa9 EB |
87 | put_pid(filp->f_owner.pid); |
88 | filp->f_owner.pid = get_pid(pid); | |
89 | filp->f_owner.pid_type = type; | |
2f38d70f ON |
90 | |
91 | if (pid) { | |
92 | const struct cred *cred = current_cred(); | |
93 | filp->f_owner.uid = cred->uid; | |
94 | filp->f_owner.euid = cred->euid; | |
95 | } | |
1da177e4 | 96 | } |
80e1e823 | 97 | write_unlock_irq(&filp->f_owner.lock); |
1da177e4 LT |
98 | } |
99 | ||
609d7fa9 EB |
100 | int __f_setown(struct file *filp, struct pid *pid, enum pid_type type, |
101 | int force) | |
1da177e4 LT |
102 | { |
103 | int err; | |
2f38d70f | 104 | |
1da177e4 LT |
105 | err = security_file_set_fowner(filp); |
106 | if (err) | |
107 | return err; | |
108 | ||
2f38d70f | 109 | f_modown(filp, pid, type, force); |
1da177e4 LT |
110 | return 0; |
111 | } | |
609d7fa9 | 112 | EXPORT_SYMBOL(__f_setown); |
1da177e4 | 113 | |
609d7fa9 EB |
114 | int f_setown(struct file *filp, unsigned long arg, int force) |
115 | { | |
116 | enum pid_type type; | |
117 | struct pid *pid; | |
118 | int who = arg; | |
119 | int result; | |
120 | type = PIDTYPE_PID; | |
121 | if (who < 0) { | |
122 | type = PIDTYPE_PGID; | |
123 | who = -who; | |
124 | } | |
125 | rcu_read_lock(); | |
b488893a | 126 | pid = find_vpid(who); |
609d7fa9 EB |
127 | result = __f_setown(filp, pid, type, force); |
128 | rcu_read_unlock(); | |
129 | return result; | |
130 | } | |
1da177e4 LT |
131 | EXPORT_SYMBOL(f_setown); |
132 | ||
133 | void f_delown(struct file *filp) | |
134 | { | |
2f38d70f | 135 | f_modown(filp, NULL, PIDTYPE_PID, 1); |
609d7fa9 EB |
136 | } |
137 | ||
138 | pid_t f_getown(struct file *filp) | |
139 | { | |
140 | pid_t pid; | |
43fa1adb | 141 | read_lock(&filp->f_owner.lock); |
6c5f3e7b | 142 | pid = pid_vnr(filp->f_owner.pid); |
609d7fa9 EB |
143 | if (filp->f_owner.pid_type == PIDTYPE_PGID) |
144 | pid = -pid; | |
43fa1adb | 145 | read_unlock(&filp->f_owner.lock); |
609d7fa9 | 146 | return pid; |
1da177e4 LT |
147 | } |
148 | ||
ba0a6c9f PZ |
149 | static int f_setown_ex(struct file *filp, unsigned long arg) |
150 | { | |
63784dd0 | 151 | struct f_owner_ex __user *owner_p = (void __user *)arg; |
ba0a6c9f PZ |
152 | struct f_owner_ex owner; |
153 | struct pid *pid; | |
154 | int type; | |
155 | int ret; | |
156 | ||
157 | ret = copy_from_user(&owner, owner_p, sizeof(owner)); | |
158 | if (ret) | |
5b54470d | 159 | return -EFAULT; |
ba0a6c9f PZ |
160 | |
161 | switch (owner.type) { | |
162 | case F_OWNER_TID: | |
163 | type = PIDTYPE_MAX; | |
164 | break; | |
165 | ||
166 | case F_OWNER_PID: | |
167 | type = PIDTYPE_PID; | |
168 | break; | |
169 | ||
978b4053 | 170 | case F_OWNER_PGRP: |
ba0a6c9f PZ |
171 | type = PIDTYPE_PGID; |
172 | break; | |
173 | ||
174 | default: | |
175 | return -EINVAL; | |
176 | } | |
177 | ||
178 | rcu_read_lock(); | |
179 | pid = find_vpid(owner.pid); | |
180 | if (owner.pid && !pid) | |
181 | ret = -ESRCH; | |
182 | else | |
183 | ret = __f_setown(filp, pid, type, 1); | |
184 | rcu_read_unlock(); | |
185 | ||
186 | return ret; | |
187 | } | |
188 | ||
189 | static int f_getown_ex(struct file *filp, unsigned long arg) | |
190 | { | |
63784dd0 | 191 | struct f_owner_ex __user *owner_p = (void __user *)arg; |
ba0a6c9f PZ |
192 | struct f_owner_ex owner; |
193 | int ret = 0; | |
194 | ||
195 | read_lock(&filp->f_owner.lock); | |
196 | owner.pid = pid_vnr(filp->f_owner.pid); | |
197 | switch (filp->f_owner.pid_type) { | |
198 | case PIDTYPE_MAX: | |
199 | owner.type = F_OWNER_TID; | |
200 | break; | |
201 | ||
202 | case PIDTYPE_PID: | |
203 | owner.type = F_OWNER_PID; | |
204 | break; | |
205 | ||
206 | case PIDTYPE_PGID: | |
978b4053 | 207 | owner.type = F_OWNER_PGRP; |
ba0a6c9f PZ |
208 | break; |
209 | ||
210 | default: | |
211 | WARN_ON(1); | |
212 | ret = -EINVAL; | |
213 | break; | |
214 | } | |
215 | read_unlock(&filp->f_owner.lock); | |
216 | ||
5b54470d | 217 | if (!ret) { |
ba0a6c9f | 218 | ret = copy_to_user(owner_p, &owner, sizeof(owner)); |
5b54470d DC |
219 | if (ret) |
220 | ret = -EFAULT; | |
221 | } | |
ba0a6c9f PZ |
222 | return ret; |
223 | } | |
224 | ||
1d151c33 CG |
225 | #ifdef CONFIG_CHECKPOINT_RESTORE |
226 | static int f_getowner_uids(struct file *filp, unsigned long arg) | |
227 | { | |
228 | struct user_namespace *user_ns = current_user_ns(); | |
63784dd0 | 229 | uid_t __user *dst = (void __user *)arg; |
1d151c33 CG |
230 | uid_t src[2]; |
231 | int err; | |
232 | ||
233 | read_lock(&filp->f_owner.lock); | |
234 | src[0] = from_kuid(user_ns, filp->f_owner.uid); | |
235 | src[1] = from_kuid(user_ns, filp->f_owner.euid); | |
236 | read_unlock(&filp->f_owner.lock); | |
237 | ||
238 | err = put_user(src[0], &dst[0]); | |
239 | err |= put_user(src[1], &dst[1]); | |
240 | ||
241 | return err; | |
242 | } | |
243 | #else | |
244 | static int f_getowner_uids(struct file *filp, unsigned long arg) | |
245 | { | |
246 | return -EINVAL; | |
247 | } | |
248 | #endif | |
249 | ||
1da177e4 LT |
250 | static long do_fcntl(int fd, unsigned int cmd, unsigned long arg, |
251 | struct file *filp) | |
252 | { | |
253 | long err = -EINVAL; | |
254 | ||
255 | switch (cmd) { | |
256 | case F_DUPFD: | |
fe17f22d AV |
257 | err = f_dupfd(arg, filp, 0); |
258 | break; | |
22d2b35b | 259 | case F_DUPFD_CLOEXEC: |
12197718 | 260 | err = f_dupfd(arg, filp, O_CLOEXEC); |
1da177e4 LT |
261 | break; |
262 | case F_GETFD: | |
263 | err = get_close_on_exec(fd) ? FD_CLOEXEC : 0; | |
264 | break; | |
265 | case F_SETFD: | |
266 | err = 0; | |
267 | set_close_on_exec(fd, arg & FD_CLOEXEC); | |
268 | break; | |
269 | case F_GETFL: | |
270 | err = filp->f_flags; | |
271 | break; | |
272 | case F_SETFL: | |
273 | err = setfl(fd, filp, arg); | |
274 | break; | |
275 | case F_GETLK: | |
276 | err = fcntl_getlk(filp, (struct flock __user *) arg); | |
277 | break; | |
278 | case F_SETLK: | |
279 | case F_SETLKW: | |
c293621b | 280 | err = fcntl_setlk(fd, filp, cmd, (struct flock __user *) arg); |
1da177e4 LT |
281 | break; |
282 | case F_GETOWN: | |
283 | /* | |
284 | * XXX If f_owner is a process group, the | |
285 | * negative return value will get converted | |
286 | * into an error. Oops. If we keep the | |
287 | * current syscall conventions, the only way | |
288 | * to fix this will be in libc. | |
289 | */ | |
609d7fa9 | 290 | err = f_getown(filp); |
1da177e4 LT |
291 | force_successful_syscall_return(); |
292 | break; | |
293 | case F_SETOWN: | |
294 | err = f_setown(filp, arg, 1); | |
295 | break; | |
ba0a6c9f PZ |
296 | case F_GETOWN_EX: |
297 | err = f_getown_ex(filp, arg); | |
298 | break; | |
299 | case F_SETOWN_EX: | |
300 | err = f_setown_ex(filp, arg); | |
301 | break; | |
1d151c33 CG |
302 | case F_GETOWNER_UIDS: |
303 | err = f_getowner_uids(filp, arg); | |
304 | break; | |
1da177e4 LT |
305 | case F_GETSIG: |
306 | err = filp->f_owner.signum; | |
307 | break; | |
308 | case F_SETSIG: | |
309 | /* arg == 0 restores default behaviour. */ | |
7ed20e1a | 310 | if (!valid_signal(arg)) { |
1da177e4 LT |
311 | break; |
312 | } | |
313 | err = 0; | |
314 | filp->f_owner.signum = arg; | |
315 | break; | |
316 | case F_GETLEASE: | |
317 | err = fcntl_getlease(filp); | |
318 | break; | |
319 | case F_SETLEASE: | |
320 | err = fcntl_setlease(fd, filp, arg); | |
321 | break; | |
322 | case F_NOTIFY: | |
323 | err = fcntl_dirnotify(fd, filp, arg); | |
324 | break; | |
35f3d14d JA |
325 | case F_SETPIPE_SZ: |
326 | case F_GETPIPE_SZ: | |
327 | err = pipe_fcntl(filp, cmd, arg); | |
328 | break; | |
1da177e4 LT |
329 | default: |
330 | break; | |
331 | } | |
332 | return err; | |
333 | } | |
334 | ||
1abf0c71 AV |
335 | static int check_fcntl_cmd(unsigned cmd) |
336 | { | |
337 | switch (cmd) { | |
338 | case F_DUPFD: | |
339 | case F_DUPFD_CLOEXEC: | |
340 | case F_GETFD: | |
341 | case F_SETFD: | |
342 | case F_GETFL: | |
343 | return 1; | |
344 | } | |
345 | return 0; | |
346 | } | |
347 | ||
a26eab24 | 348 | SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd, unsigned long, arg) |
1da177e4 | 349 | { |
2903ff01 | 350 | struct fd f = fdget_raw(fd); |
1da177e4 LT |
351 | long err = -EBADF; |
352 | ||
2903ff01 | 353 | if (!f.file) |
1da177e4 LT |
354 | goto out; |
355 | ||
2903ff01 | 356 | if (unlikely(f.file->f_mode & FMODE_PATH)) { |
545ec2c7 AV |
357 | if (!check_fcntl_cmd(cmd)) |
358 | goto out1; | |
1abf0c71 AV |
359 | } |
360 | ||
2903ff01 | 361 | err = security_file_fcntl(f.file, cmd, arg); |
545ec2c7 | 362 | if (!err) |
2903ff01 | 363 | err = do_fcntl(fd, cmd, arg, f.file); |
1da177e4 | 364 | |
545ec2c7 | 365 | out1: |
2903ff01 | 366 | fdput(f); |
1da177e4 LT |
367 | out: |
368 | return err; | |
369 | } | |
370 | ||
371 | #if BITS_PER_LONG == 32 | |
a26eab24 HC |
372 | SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd, |
373 | unsigned long, arg) | |
1da177e4 | 374 | { |
2903ff01 | 375 | struct fd f = fdget_raw(fd); |
545ec2c7 | 376 | long err = -EBADF; |
1da177e4 | 377 | |
2903ff01 | 378 | if (!f.file) |
1da177e4 LT |
379 | goto out; |
380 | ||
2903ff01 | 381 | if (unlikely(f.file->f_mode & FMODE_PATH)) { |
545ec2c7 AV |
382 | if (!check_fcntl_cmd(cmd)) |
383 | goto out1; | |
1abf0c71 AV |
384 | } |
385 | ||
2903ff01 | 386 | err = security_file_fcntl(f.file, cmd, arg); |
545ec2c7 AV |
387 | if (err) |
388 | goto out1; | |
1da177e4 LT |
389 | |
390 | switch (cmd) { | |
391 | case F_GETLK64: | |
2903ff01 | 392 | err = fcntl_getlk64(f.file, (struct flock64 __user *) arg); |
1da177e4 LT |
393 | break; |
394 | case F_SETLK64: | |
395 | case F_SETLKW64: | |
2903ff01 | 396 | err = fcntl_setlk64(fd, f.file, cmd, |
c293621b | 397 | (struct flock64 __user *) arg); |
1da177e4 LT |
398 | break; |
399 | default: | |
2903ff01 | 400 | err = do_fcntl(fd, cmd, arg, f.file); |
1da177e4 LT |
401 | break; |
402 | } | |
545ec2c7 | 403 | out1: |
2903ff01 | 404 | fdput(f); |
1da177e4 LT |
405 | out: |
406 | return err; | |
407 | } | |
408 | #endif | |
409 | ||
410 | /* Table to convert sigio signal codes into poll band bitmaps */ | |
411 | ||
fa3536cc | 412 | static const long band_table[NSIGPOLL] = { |
1da177e4 LT |
413 | POLLIN | POLLRDNORM, /* POLL_IN */ |
414 | POLLOUT | POLLWRNORM | POLLWRBAND, /* POLL_OUT */ | |
415 | POLLIN | POLLRDNORM | POLLMSG, /* POLL_MSG */ | |
416 | POLLERR, /* POLL_ERR */ | |
417 | POLLPRI | POLLRDBAND, /* POLL_PRI */ | |
418 | POLLHUP | POLLERR /* POLL_HUP */ | |
419 | }; | |
420 | ||
421 | static inline int sigio_perm(struct task_struct *p, | |
422 | struct fown_struct *fown, int sig) | |
423 | { | |
c69e8d9c DH |
424 | const struct cred *cred; |
425 | int ret; | |
426 | ||
427 | rcu_read_lock(); | |
428 | cred = __task_cred(p); | |
8e96e3b7 EB |
429 | ret = ((uid_eq(fown->euid, GLOBAL_ROOT_UID) || |
430 | uid_eq(fown->euid, cred->suid) || uid_eq(fown->euid, cred->uid) || | |
431 | uid_eq(fown->uid, cred->suid) || uid_eq(fown->uid, cred->uid)) && | |
c69e8d9c DH |
432 | !security_file_send_sigiotask(p, fown, sig)); |
433 | rcu_read_unlock(); | |
434 | return ret; | |
1da177e4 LT |
435 | } |
436 | ||
437 | static void send_sigio_to_task(struct task_struct *p, | |
8eeee4e2 | 438 | struct fown_struct *fown, |
ba0a6c9f | 439 | int fd, int reason, int group) |
1da177e4 | 440 | { |
8eeee4e2 ON |
441 | /* |
442 | * F_SETSIG can change ->signum lockless in parallel, make | |
443 | * sure we read it once and use the same value throughout. | |
444 | */ | |
445 | int signum = ACCESS_ONCE(fown->signum); | |
446 | ||
447 | if (!sigio_perm(p, fown, signum)) | |
1da177e4 LT |
448 | return; |
449 | ||
8eeee4e2 | 450 | switch (signum) { |
1da177e4 LT |
451 | siginfo_t si; |
452 | default: | |
453 | /* Queue a rt signal with the appropriate fd as its | |
454 | value. We use SI_SIGIO as the source, not | |
455 | SI_KERNEL, since kernel signals always get | |
456 | delivered even if we can't queue. Failure to | |
457 | queue in this case _should_ be reported; we fall | |
458 | back to SIGIO in that case. --sct */ | |
8eeee4e2 | 459 | si.si_signo = signum; |
1da177e4 LT |
460 | si.si_errno = 0; |
461 | si.si_code = reason; | |
462 | /* Make sure we are called with one of the POLL_* | |
463 | reasons, otherwise we could leak kernel stack into | |
464 | userspace. */ | |
f6298aab | 465 | BUG_ON((reason & __SI_MASK) != __SI_POLL); |
1da177e4 LT |
466 | if (reason - POLL_IN >= NSIGPOLL) |
467 | si.si_band = ~0L; | |
468 | else | |
469 | si.si_band = band_table[reason - POLL_IN]; | |
470 | si.si_fd = fd; | |
ba0a6c9f | 471 | if (!do_send_sig_info(signum, &si, p, group)) |
1da177e4 LT |
472 | break; |
473 | /* fall-through: fall back on the old plain SIGIO signal */ | |
474 | case 0: | |
ba0a6c9f | 475 | do_send_sig_info(SIGIO, SEND_SIG_PRIV, p, group); |
1da177e4 LT |
476 | } |
477 | } | |
478 | ||
479 | void send_sigio(struct fown_struct *fown, int fd, int band) | |
480 | { | |
481 | struct task_struct *p; | |
609d7fa9 EB |
482 | enum pid_type type; |
483 | struct pid *pid; | |
ba0a6c9f | 484 | int group = 1; |
1da177e4 LT |
485 | |
486 | read_lock(&fown->lock); | |
ba0a6c9f | 487 | |
609d7fa9 | 488 | type = fown->pid_type; |
ba0a6c9f PZ |
489 | if (type == PIDTYPE_MAX) { |
490 | group = 0; | |
491 | type = PIDTYPE_PID; | |
492 | } | |
493 | ||
1da177e4 LT |
494 | pid = fown->pid; |
495 | if (!pid) | |
496 | goto out_unlock_fown; | |
497 | ||
498 | read_lock(&tasklist_lock); | |
609d7fa9 | 499 | do_each_pid_task(pid, type, p) { |
ba0a6c9f | 500 | send_sigio_to_task(p, fown, fd, band, group); |
609d7fa9 | 501 | } while_each_pid_task(pid, type, p); |
1da177e4 LT |
502 | read_unlock(&tasklist_lock); |
503 | out_unlock_fown: | |
504 | read_unlock(&fown->lock); | |
505 | } | |
506 | ||
507 | static void send_sigurg_to_task(struct task_struct *p, | |
ba0a6c9f | 508 | struct fown_struct *fown, int group) |
1da177e4 LT |
509 | { |
510 | if (sigio_perm(p, fown, SIGURG)) | |
ba0a6c9f | 511 | do_send_sig_info(SIGURG, SEND_SIG_PRIV, p, group); |
1da177e4 LT |
512 | } |
513 | ||
514 | int send_sigurg(struct fown_struct *fown) | |
515 | { | |
516 | struct task_struct *p; | |
609d7fa9 EB |
517 | enum pid_type type; |
518 | struct pid *pid; | |
ba0a6c9f | 519 | int group = 1; |
609d7fa9 | 520 | int ret = 0; |
1da177e4 LT |
521 | |
522 | read_lock(&fown->lock); | |
ba0a6c9f | 523 | |
609d7fa9 | 524 | type = fown->pid_type; |
ba0a6c9f PZ |
525 | if (type == PIDTYPE_MAX) { |
526 | group = 0; | |
527 | type = PIDTYPE_PID; | |
528 | } | |
529 | ||
1da177e4 LT |
530 | pid = fown->pid; |
531 | if (!pid) | |
532 | goto out_unlock_fown; | |
533 | ||
534 | ret = 1; | |
535 | ||
536 | read_lock(&tasklist_lock); | |
609d7fa9 | 537 | do_each_pid_task(pid, type, p) { |
ba0a6c9f | 538 | send_sigurg_to_task(p, fown, group); |
609d7fa9 | 539 | } while_each_pid_task(pid, type, p); |
1da177e4 LT |
540 | read_unlock(&tasklist_lock); |
541 | out_unlock_fown: | |
542 | read_unlock(&fown->lock); | |
543 | return ret; | |
544 | } | |
545 | ||
989a2979 | 546 | static DEFINE_SPINLOCK(fasync_lock); |
e18b890b | 547 | static struct kmem_cache *fasync_cache __read_mostly; |
1da177e4 | 548 | |
989a2979 ED |
549 | static void fasync_free_rcu(struct rcu_head *head) |
550 | { | |
551 | kmem_cache_free(fasync_cache, | |
552 | container_of(head, struct fasync_struct, fa_rcu)); | |
553 | } | |
554 | ||
1da177e4 | 555 | /* |
53281b6d LT |
556 | * Remove a fasync entry. If successfully removed, return |
557 | * positive and clear the FASYNC flag. If no entry exists, | |
558 | * do nothing and return 0. | |
559 | * | |
560 | * NOTE! It is very important that the FASYNC flag always | |
561 | * match the state "is the filp on a fasync list". | |
562 | * | |
1da177e4 | 563 | */ |
f7347ce4 | 564 | int fasync_remove_entry(struct file *filp, struct fasync_struct **fapp) |
1da177e4 LT |
565 | { |
566 | struct fasync_struct *fa, **fp; | |
1da177e4 LT |
567 | int result = 0; |
568 | ||
53281b6d | 569 | spin_lock(&filp->f_lock); |
989a2979 | 570 | spin_lock(&fasync_lock); |
53281b6d LT |
571 | for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) { |
572 | if (fa->fa_file != filp) | |
573 | continue; | |
989a2979 ED |
574 | |
575 | spin_lock_irq(&fa->fa_lock); | |
576 | fa->fa_file = NULL; | |
577 | spin_unlock_irq(&fa->fa_lock); | |
578 | ||
53281b6d | 579 | *fp = fa->fa_next; |
989a2979 | 580 | call_rcu(&fa->fa_rcu, fasync_free_rcu); |
53281b6d LT |
581 | filp->f_flags &= ~FASYNC; |
582 | result = 1; | |
583 | break; | |
1da177e4 | 584 | } |
989a2979 | 585 | spin_unlock(&fasync_lock); |
53281b6d LT |
586 | spin_unlock(&filp->f_lock); |
587 | return result; | |
588 | } | |
589 | ||
f7347ce4 LT |
590 | struct fasync_struct *fasync_alloc(void) |
591 | { | |
592 | return kmem_cache_alloc(fasync_cache, GFP_KERNEL); | |
593 | } | |
594 | ||
53281b6d | 595 | /* |
f7347ce4 LT |
596 | * NOTE! This can be used only for unused fasync entries: |
597 | * entries that actually got inserted on the fasync list | |
598 | * need to be released by rcu - see fasync_remove_entry. | |
53281b6d | 599 | */ |
f7347ce4 | 600 | void fasync_free(struct fasync_struct *new) |
53281b6d | 601 | { |
f7347ce4 LT |
602 | kmem_cache_free(fasync_cache, new); |
603 | } | |
53281b6d | 604 | |
f7347ce4 LT |
605 | /* |
606 | * Insert a new entry into the fasync list. Return the pointer to the | |
607 | * old one if we didn't use the new one. | |
55f335a8 LT |
608 | * |
609 | * NOTE! It is very important that the FASYNC flag always | |
610 | * match the state "is the filp on a fasync list". | |
f7347ce4 LT |
611 | */ |
612 | struct fasync_struct *fasync_insert_entry(int fd, struct file *filp, struct fasync_struct **fapp, struct fasync_struct *new) | |
613 | { | |
614 | struct fasync_struct *fa, **fp; | |
4a6a4499 | 615 | |
4a6a4499 | 616 | spin_lock(&filp->f_lock); |
989a2979 | 617 | spin_lock(&fasync_lock); |
1da177e4 | 618 | for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) { |
53281b6d LT |
619 | if (fa->fa_file != filp) |
620 | continue; | |
989a2979 ED |
621 | |
622 | spin_lock_irq(&fa->fa_lock); | |
53281b6d | 623 | fa->fa_fd = fd; |
989a2979 | 624 | spin_unlock_irq(&fa->fa_lock); |
53281b6d | 625 | goto out; |
1da177e4 LT |
626 | } |
627 | ||
989a2979 | 628 | spin_lock_init(&new->fa_lock); |
53281b6d LT |
629 | new->magic = FASYNC_MAGIC; |
630 | new->fa_file = filp; | |
631 | new->fa_fd = fd; | |
632 | new->fa_next = *fapp; | |
989a2979 | 633 | rcu_assign_pointer(*fapp, new); |
53281b6d LT |
634 | filp->f_flags |= FASYNC; |
635 | ||
1da177e4 | 636 | out: |
989a2979 | 637 | spin_unlock(&fasync_lock); |
4a6a4499 | 638 | spin_unlock(&filp->f_lock); |
f7347ce4 LT |
639 | return fa; |
640 | } | |
641 | ||
642 | /* | |
643 | * Add a fasync entry. Return negative on error, positive if | |
644 | * added, and zero if did nothing but change an existing one. | |
f7347ce4 LT |
645 | */ |
646 | static int fasync_add_entry(int fd, struct file *filp, struct fasync_struct **fapp) | |
647 | { | |
648 | struct fasync_struct *new; | |
649 | ||
650 | new = fasync_alloc(); | |
651 | if (!new) | |
652 | return -ENOMEM; | |
653 | ||
654 | /* | |
655 | * fasync_insert_entry() returns the old (update) entry if | |
656 | * it existed. | |
657 | * | |
658 | * So free the (unused) new entry and return 0 to let the | |
659 | * caller know that we didn't add any new fasync entries. | |
660 | */ | |
661 | if (fasync_insert_entry(fd, filp, fapp, new)) { | |
662 | fasync_free(new); | |
663 | return 0; | |
664 | } | |
665 | ||
666 | return 1; | |
1da177e4 LT |
667 | } |
668 | ||
53281b6d LT |
669 | /* |
670 | * fasync_helper() is used by almost all character device drivers | |
671 | * to set up the fasync queue, and for regular files by the file | |
672 | * lease code. It returns negative on error, 0 if it did no changes | |
673 | * and positive if it added/deleted the entry. | |
674 | */ | |
675 | int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp) | |
676 | { | |
677 | if (!on) | |
678 | return fasync_remove_entry(filp, fapp); | |
679 | return fasync_add_entry(fd, filp, fapp); | |
680 | } | |
681 | ||
1da177e4 LT |
682 | EXPORT_SYMBOL(fasync_helper); |
683 | ||
989a2979 ED |
684 | /* |
685 | * rcu_read_lock() is held | |
686 | */ | |
687 | static void kill_fasync_rcu(struct fasync_struct *fa, int sig, int band) | |
1da177e4 LT |
688 | { |
689 | while (fa) { | |
989a2979 | 690 | struct fown_struct *fown; |
f4985dc7 AM |
691 | unsigned long flags; |
692 | ||
1da177e4 LT |
693 | if (fa->magic != FASYNC_MAGIC) { |
694 | printk(KERN_ERR "kill_fasync: bad magic number in " | |
695 | "fasync_struct!\n"); | |
696 | return; | |
697 | } | |
f4985dc7 | 698 | spin_lock_irqsave(&fa->fa_lock, flags); |
989a2979 ED |
699 | if (fa->fa_file) { |
700 | fown = &fa->fa_file->f_owner; | |
701 | /* Don't send SIGURG to processes which have not set a | |
702 | queued signum: SIGURG has its own default signalling | |
703 | mechanism. */ | |
704 | if (!(sig == SIGURG && fown->signum == 0)) | |
705 | send_sigio(fown, fa->fa_fd, band); | |
706 | } | |
f4985dc7 | 707 | spin_unlock_irqrestore(&fa->fa_lock, flags); |
989a2979 | 708 | fa = rcu_dereference(fa->fa_next); |
1da177e4 LT |
709 | } |
710 | } | |
711 | ||
1da177e4 LT |
712 | void kill_fasync(struct fasync_struct **fp, int sig, int band) |
713 | { | |
714 | /* First a quick test without locking: usually | |
715 | * the list is empty. | |
716 | */ | |
717 | if (*fp) { | |
989a2979 ED |
718 | rcu_read_lock(); |
719 | kill_fasync_rcu(rcu_dereference(*fp), sig, band); | |
720 | rcu_read_unlock(); | |
1da177e4 LT |
721 | } |
722 | } | |
723 | EXPORT_SYMBOL(kill_fasync); | |
724 | ||
454eedb8 | 725 | static int __init fcntl_init(void) |
1da177e4 | 726 | { |
3ab04d5c JB |
727 | /* |
728 | * Please add new bits here to ensure allocation uniqueness. | |
729 | * Exceptions: O_NONBLOCK is a two bit define on parisc; O_NDELAY | |
730 | * is defined as O_NONBLOCK on some platforms and not on others. | |
731 | */ | |
3d62c45b | 732 | BUILD_BUG_ON(20 - 1 /* for O_RDONLY being 0 */ != HWEIGHT32( |
454eedb8 WF |
733 | O_RDONLY | O_WRONLY | O_RDWR | |
734 | O_CREAT | O_EXCL | O_NOCTTY | | |
3ab04d5c | 735 | O_TRUNC | O_APPEND | /* O_NONBLOCK | */ |
454eedb8 WF |
736 | __O_SYNC | O_DSYNC | FASYNC | |
737 | O_DIRECT | O_LARGEFILE | O_DIRECTORY | | |
738 | O_NOFOLLOW | O_NOATIME | O_CLOEXEC | | |
3d62c45b | 739 | __FMODE_EXEC | O_PATH | __O_TMPFILE |
454eedb8 WF |
740 | )); |
741 | ||
1da177e4 | 742 | fasync_cache = kmem_cache_create("fasync_cache", |
20c2df83 | 743 | sizeof(struct fasync_struct), 0, SLAB_PANIC, NULL); |
1da177e4 LT |
744 | return 0; |
745 | } | |
746 | ||
454eedb8 | 747 | module_init(fcntl_init) |