blob: d865ca66ccba1a6fb331150a75c7d50b5545e87c [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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>
Al Viro9f3acc32008-04-24 07:44:08 -040012#include <linux/fdtable.h>
Randy Dunlap16f7e0f2006-01-11 12:17:46 -080013#include <linux/capability.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070014#include <linux/dnotify.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070015#include <linux/slab.h>
16#include <linux/module.h>
17#include <linux/security.h>
18#include <linux/ptrace.h>
Jesper Juhl7ed20e12005-05-01 08:59:14 -070019#include <linux/signal.h>
Dipankar Sarmaab2af1f2005-09-09 13:04:13 -070020#include <linux/rcupdate.h>
Pavel Emelyanovb4888932007-10-18 23:40:14 -070021#include <linux/pid_namespace.h>
Jonathan Corbet218d11a2008-12-05 16:12:48 -070022#include <linux/smp_lock.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070023
24#include <asm/poll.h>
25#include <asm/siginfo.h>
26#include <asm/uaccess.h>
27
Harvey Harrisonfc9b52c2008-02-08 04:19:52 -080028void set_close_on_exec(unsigned int fd, int flag)
Linus Torvalds1da177e2005-04-16 15:20:36 -070029{
30 struct files_struct *files = current->files;
Dipankar Sarmabadf1662005-09-09 13:04:10 -070031 struct fdtable *fdt;
Linus Torvalds1da177e2005-04-16 15:20:36 -070032 spin_lock(&files->file_lock);
Dipankar Sarmabadf1662005-09-09 13:04:10 -070033 fdt = files_fdtable(files);
Linus Torvalds1da177e2005-04-16 15:20:36 -070034 if (flag)
Dipankar Sarmabadf1662005-09-09 13:04:10 -070035 FD_SET(fd, fdt->close_on_exec);
Linus Torvalds1da177e2005-04-16 15:20:36 -070036 else
Dipankar Sarmabadf1662005-09-09 13:04:10 -070037 FD_CLR(fd, fdt->close_on_exec);
Linus Torvalds1da177e2005-04-16 15:20:36 -070038 spin_unlock(&files->file_lock);
39}
40
Arjan van de Ven858119e2006-01-14 13:20:43 -080041static int get_close_on_exec(unsigned int fd)
Linus Torvalds1da177e2005-04-16 15:20:36 -070042{
43 struct files_struct *files = current->files;
Dipankar Sarmabadf1662005-09-09 13:04:10 -070044 struct fdtable *fdt;
Linus Torvalds1da177e2005-04-16 15:20:36 -070045 int res;
Dipankar Sarmab8359962005-09-09 13:04:14 -070046 rcu_read_lock();
Dipankar Sarmabadf1662005-09-09 13:04:10 -070047 fdt = files_fdtable(files);
48 res = FD_ISSET(fd, fdt->close_on_exec);
Dipankar Sarmab8359962005-09-09 13:04:14 -070049 rcu_read_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -070050 return res;
51}
52
Heiko Carstensa26eab22009-01-14 14:14:17 +010053SYSCALL_DEFINE3(dup3, unsigned int, oldfd, unsigned int, newfd, int, flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -070054{
55 int err = -EBADF;
56 struct file * file, *tofree;
57 struct files_struct * files = current->files;
Dipankar Sarmabadf1662005-09-09 13:04:10 -070058 struct fdtable *fdt;
Linus Torvalds1da177e2005-04-16 15:20:36 -070059
Ulrich Drepper336dd1f2008-07-23 21:29:29 -070060 if ((flags & ~O_CLOEXEC) != 0)
61 return -EINVAL;
62
Al Viro6c5d0512008-07-26 13:38:19 -040063 if (unlikely(oldfd == newfd))
64 return -EINVAL;
65
Linus Torvalds1da177e2005-04-16 15:20:36 -070066 spin_lock(&files->file_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -070067 err = expand_files(files, newfd);
Al Viro1b7e1902008-07-30 06:18:03 -040068 file = fcheck(oldfd);
69 if (unlikely(!file))
70 goto Ebadf;
Al Viro4e1e0182008-07-26 16:01:20 -040071 if (unlikely(err < 0)) {
72 if (err == -EMFILE)
Al Viro1b7e1902008-07-30 06:18:03 -040073 goto Ebadf;
74 goto out_unlock;
Al Viro4e1e0182008-07-26 16:01:20 -040075 }
Al Viro1b7e1902008-07-30 06:18:03 -040076 /*
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 */
Linus Torvalds1da177e2005-04-16 15:20:36 -070090 err = -EBUSY;
Dipankar Sarmabadf1662005-09-09 13:04:10 -070091 fdt = files_fdtable(files);
92 tofree = fdt->fd[newfd];
93 if (!tofree && FD_ISSET(newfd, fdt->open_fds))
Al Viro1b7e1902008-07-30 06:18:03 -040094 goto out_unlock;
95 get_file(file);
Dipankar Sarmaab2af1f2005-09-09 13:04:13 -070096 rcu_assign_pointer(fdt->fd[newfd], file);
Dipankar Sarmabadf1662005-09-09 13:04:10 -070097 FD_SET(newfd, fdt->open_fds);
Ulrich Drepper336dd1f2008-07-23 21:29:29 -070098 if (flags & O_CLOEXEC)
99 FD_SET(newfd, fdt->close_on_exec);
100 else
101 FD_CLR(newfd, fdt->close_on_exec);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102 spin_unlock(&files->file_lock);
103
104 if (tofree)
105 filp_close(tofree, files);
Al Viro1b7e1902008-07-30 06:18:03 -0400106
107 return newfd;
108
109Ebadf:
110 err = -EBADF;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111out_unlock:
112 spin_unlock(&files->file_lock);
Al Viro1b7e1902008-07-30 06:18:03 -0400113 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114}
115
Heiko Carstensa26eab22009-01-14 14:14:17 +0100116SYSCALL_DEFINE2(dup2, unsigned int, oldfd, unsigned int, newfd)
Ulrich Drepper336dd1f2008-07-23 21:29:29 -0700117{
Al Viro6c5d0512008-07-26 13:38:19 -0400118 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 }
Ulrich Drepper336dd1f2008-07-23 21:29:29 -0700126 return sys_dup3(oldfd, newfd, 0);
127}
128
Heiko Carstensa26eab22009-01-14 14:14:17 +0100129SYSCALL_DEFINE1(dup, unsigned int, fildes)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130{
131 int ret = -EBADF;
Al Viro1027abe2008-07-30 04:13:04 -0400132 struct file *file = fget(fildes);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700133
Al Viro1027abe2008-07-30 04:13:04 -0400134 if (file) {
135 ret = get_unused_fd();
136 if (ret >= 0)
137 fd_install(ret, file);
138 else
139 fput(file);
140 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141 return ret;
142}
143
Jonathan Corbet76398422009-02-01 14:26:59 -0700144#define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | O_DIRECT | O_NOATIME)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700145
146static int setfl(int fd, struct file * filp, unsigned long arg)
147{
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800148 struct inode * inode = filp->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149 int error = 0;
150
dean gaudet7d95c8f2006-02-03 03:04:30 -0800151 /*
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))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700156 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))
Satyam Sharma3bd858a2007-07-17 15:00:08 +0530160 if (!is_owner_or_cap(inode))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700161 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
Jonathan Corbet218d11a2008-12-05 16:12:48 -0700179 /*
Jonathan Corbet76398422009-02-01 14:26:59 -0700180 * ->fasync() is responsible for setting the FASYNC bit.
Jonathan Corbet218d11a2008-12-05 16:12:48 -0700181 */
Jonathan Corbet76398422009-02-01 14:26:59 -0700182 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;
Jonathan Corbet60aa4922009-02-01 14:52:56 -0700187 if (error > 0)
188 error = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700189 }
Jonathan Corbetdb1dd4d2009-02-06 15:25:24 -0700190 spin_lock(&filp->f_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191 filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK);
Jonathan Corbetdb1dd4d2009-02-06 15:25:24 -0700192 spin_unlock(&filp->f_lock);
Jonathan Corbet76398422009-02-01 14:26:59 -0700193
Linus Torvalds1da177e2005-04-16 15:20:36 -0700194 out:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700195 return error;
196}
197
Eric W. Biederman609d7fa2006-10-02 02:17:15 -0700198static void f_modown(struct file *filp, struct pid *pid, enum pid_type type,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700199 uid_t uid, uid_t euid, int force)
200{
201 write_lock_irq(&filp->f_owner.lock);
202 if (force || !filp->f_owner.pid) {
Eric W. Biederman609d7fa2006-10-02 02:17:15 -0700203 put_pid(filp->f_owner.pid);
204 filp->f_owner.pid = get_pid(pid);
205 filp->f_owner.pid_type = type;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700206 filp->f_owner.uid = uid;
207 filp->f_owner.euid = euid;
208 }
209 write_unlock_irq(&filp->f_owner.lock);
210}
211
Eric W. Biederman609d7fa2006-10-02 02:17:15 -0700212int __f_setown(struct file *filp, struct pid *pid, enum pid_type type,
213 int force)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700214{
David Howells86a264a2008-11-14 10:39:18 +1100215 const struct cred *cred = current_cred();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700216 int err;
217
218 err = security_file_set_fowner(filp);
219 if (err)
220 return err;
221
David Howells86a264a2008-11-14 10:39:18 +1100222 f_modown(filp, pid, type, cred->uid, cred->euid, force);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700223 return 0;
224}
Eric W. Biederman609d7fa2006-10-02 02:17:15 -0700225EXPORT_SYMBOL(__f_setown);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226
Eric W. Biederman609d7fa2006-10-02 02:17:15 -0700227int f_setown(struct file *filp, unsigned long arg, int force)
228{
229 enum pid_type type;
230 struct pid *pid;
231 int who = arg;
232 int result;
233 type = PIDTYPE_PID;
234 if (who < 0) {
235 type = PIDTYPE_PGID;
236 who = -who;
237 }
238 rcu_read_lock();
Pavel Emelyanovb4888932007-10-18 23:40:14 -0700239 pid = find_vpid(who);
Eric W. Biederman609d7fa2006-10-02 02:17:15 -0700240 result = __f_setown(filp, pid, type, force);
241 rcu_read_unlock();
242 return result;
243}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700244EXPORT_SYMBOL(f_setown);
245
246void f_delown(struct file *filp)
247{
Eric W. Biederman609d7fa2006-10-02 02:17:15 -0700248 f_modown(filp, NULL, PIDTYPE_PID, 0, 0, 1);
249}
250
251pid_t f_getown(struct file *filp)
252{
253 pid_t pid;
Eric W. Biederman43fa1ad2006-10-02 02:17:27 -0700254 read_lock(&filp->f_owner.lock);
Pavel Emelyanov6c5f3e72008-02-08 04:19:20 -0800255 pid = pid_vnr(filp->f_owner.pid);
Eric W. Biederman609d7fa2006-10-02 02:17:15 -0700256 if (filp->f_owner.pid_type == PIDTYPE_PGID)
257 pid = -pid;
Eric W. Biederman43fa1ad2006-10-02 02:17:27 -0700258 read_unlock(&filp->f_owner.lock);
Eric W. Biederman609d7fa2006-10-02 02:17:15 -0700259 return pid;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260}
261
262static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
263 struct file *filp)
264{
265 long err = -EINVAL;
266
267 switch (cmd) {
268 case F_DUPFD:
Ulrich Drepper22d2b352007-10-16 23:30:26 -0700269 case F_DUPFD_CLOEXEC:
Al Viro4e1e0182008-07-26 16:01:20 -0400270 if (arg >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
271 break;
Al Viro1027abe2008-07-30 04:13:04 -0400272 err = alloc_fd(arg, cmd == F_DUPFD_CLOEXEC ? O_CLOEXEC : 0);
273 if (err >= 0) {
274 get_file(filp);
275 fd_install(err, filp);
276 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277 break;
278 case F_GETFD:
279 err = get_close_on_exec(fd) ? FD_CLOEXEC : 0;
280 break;
281 case F_SETFD:
282 err = 0;
283 set_close_on_exec(fd, arg & FD_CLOEXEC);
284 break;
285 case F_GETFL:
286 err = filp->f_flags;
287 break;
288 case F_SETFL:
289 err = setfl(fd, filp, arg);
290 break;
291 case F_GETLK:
292 err = fcntl_getlk(filp, (struct flock __user *) arg);
293 break;
294 case F_SETLK:
295 case F_SETLKW:
Peter Staubachc2936212005-07-27 11:45:09 -0700296 err = fcntl_setlk(fd, filp, cmd, (struct flock __user *) arg);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700297 break;
298 case F_GETOWN:
299 /*
300 * XXX If f_owner is a process group, the
301 * negative return value will get converted
302 * into an error. Oops. If we keep the
303 * current syscall conventions, the only way
304 * to fix this will be in libc.
305 */
Eric W. Biederman609d7fa2006-10-02 02:17:15 -0700306 err = f_getown(filp);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700307 force_successful_syscall_return();
308 break;
309 case F_SETOWN:
310 err = f_setown(filp, arg, 1);
311 break;
312 case F_GETSIG:
313 err = filp->f_owner.signum;
314 break;
315 case F_SETSIG:
316 /* arg == 0 restores default behaviour. */
Jesper Juhl7ed20e12005-05-01 08:59:14 -0700317 if (!valid_signal(arg)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318 break;
319 }
320 err = 0;
321 filp->f_owner.signum = arg;
322 break;
323 case F_GETLEASE:
324 err = fcntl_getlease(filp);
325 break;
326 case F_SETLEASE:
327 err = fcntl_setlease(fd, filp, arg);
328 break;
329 case F_NOTIFY:
330 err = fcntl_dirnotify(fd, filp, arg);
331 break;
332 default:
333 break;
334 }
335 return err;
336}
337
Heiko Carstensa26eab22009-01-14 14:14:17 +0100338SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd, unsigned long, arg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700339{
340 struct file *filp;
341 long err = -EBADF;
342
343 filp = fget(fd);
344 if (!filp)
345 goto out;
346
347 err = security_file_fcntl(filp, cmd, arg);
348 if (err) {
349 fput(filp);
350 return err;
351 }
352
353 err = do_fcntl(fd, cmd, arg, filp);
354
355 fput(filp);
356out:
357 return err;
358}
359
360#if BITS_PER_LONG == 32
Heiko Carstensa26eab22009-01-14 14:14:17 +0100361SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd,
362 unsigned long, arg)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363{
364 struct file * filp;
365 long err;
366
367 err = -EBADF;
368 filp = fget(fd);
369 if (!filp)
370 goto out;
371
372 err = security_file_fcntl(filp, cmd, arg);
373 if (err) {
374 fput(filp);
375 return err;
376 }
377 err = -EBADF;
378
379 switch (cmd) {
380 case F_GETLK64:
381 err = fcntl_getlk64(filp, (struct flock64 __user *) arg);
382 break;
383 case F_SETLK64:
384 case F_SETLKW64:
Peter Staubachc2936212005-07-27 11:45:09 -0700385 err = fcntl_setlk64(fd, filp, cmd,
386 (struct flock64 __user *) arg);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700387 break;
388 default:
389 err = do_fcntl(fd, cmd, arg, filp);
390 break;
391 }
392 fput(filp);
393out:
394 return err;
395}
396#endif
397
398/* Table to convert sigio signal codes into poll band bitmaps */
399
Eric Dumazetfa3536c2006-03-26 01:37:24 -0800400static const long band_table[NSIGPOLL] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700401 POLLIN | POLLRDNORM, /* POLL_IN */
402 POLLOUT | POLLWRNORM | POLLWRBAND, /* POLL_OUT */
403 POLLIN | POLLRDNORM | POLLMSG, /* POLL_MSG */
404 POLLERR, /* POLL_ERR */
405 POLLPRI | POLLRDBAND, /* POLL_PRI */
406 POLLHUP | POLLERR /* POLL_HUP */
407};
408
409static inline int sigio_perm(struct task_struct *p,
410 struct fown_struct *fown, int sig)
411{
David Howellsc69e8d92008-11-14 10:39:19 +1100412 const struct cred *cred;
413 int ret;
414
415 rcu_read_lock();
416 cred = __task_cred(p);
417 ret = ((fown->euid == 0 ||
418 fown->euid == cred->suid || fown->euid == cred->uid ||
419 fown->uid == cred->suid || fown->uid == cred->uid) &&
420 !security_file_send_sigiotask(p, fown, sig));
421 rcu_read_unlock();
422 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700423}
424
425static void send_sigio_to_task(struct task_struct *p,
426 struct fown_struct *fown,
427 int fd,
428 int reason)
429{
430 if (!sigio_perm(p, fown, fown->signum))
431 return;
432
433 switch (fown->signum) {
434 siginfo_t si;
435 default:
436 /* Queue a rt signal with the appropriate fd as its
437 value. We use SI_SIGIO as the source, not
438 SI_KERNEL, since kernel signals always get
439 delivered even if we can't queue. Failure to
440 queue in this case _should_ be reported; we fall
441 back to SIGIO in that case. --sct */
442 si.si_signo = fown->signum;
443 si.si_errno = 0;
444 si.si_code = reason;
445 /* Make sure we are called with one of the POLL_*
446 reasons, otherwise we could leak kernel stack into
447 userspace. */
Eric Sesterhennf6298aa2006-04-02 13:37:19 +0200448 BUG_ON((reason & __SI_MASK) != __SI_POLL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700449 if (reason - POLL_IN >= NSIGPOLL)
450 si.si_band = ~0L;
451 else
452 si.si_band = band_table[reason - POLL_IN];
453 si.si_fd = fd;
Oleg Nesterov850d6fb2006-01-08 01:03:29 -0800454 if (!group_send_sig_info(fown->signum, &si, p))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700455 break;
456 /* fall-through: fall back on the old plain SIGIO signal */
457 case 0:
Oleg Nesterov850d6fb2006-01-08 01:03:29 -0800458 group_send_sig_info(SIGIO, SEND_SIG_PRIV, p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700459 }
460}
461
462void send_sigio(struct fown_struct *fown, int fd, int band)
463{
464 struct task_struct *p;
Eric W. Biederman609d7fa2006-10-02 02:17:15 -0700465 enum pid_type type;
466 struct pid *pid;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700467
468 read_lock(&fown->lock);
Eric W. Biederman609d7fa2006-10-02 02:17:15 -0700469 type = fown->pid_type;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700470 pid = fown->pid;
471 if (!pid)
472 goto out_unlock_fown;
473
474 read_lock(&tasklist_lock);
Eric W. Biederman609d7fa2006-10-02 02:17:15 -0700475 do_each_pid_task(pid, type, p) {
476 send_sigio_to_task(p, fown, fd, band);
477 } while_each_pid_task(pid, type, p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478 read_unlock(&tasklist_lock);
479 out_unlock_fown:
480 read_unlock(&fown->lock);
481}
482
483static void send_sigurg_to_task(struct task_struct *p,
484 struct fown_struct *fown)
485{
486 if (sigio_perm(p, fown, SIGURG))
Oleg Nesterov850d6fb2006-01-08 01:03:29 -0800487 group_send_sig_info(SIGURG, SEND_SIG_PRIV, p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700488}
489
490int send_sigurg(struct fown_struct *fown)
491{
492 struct task_struct *p;
Eric W. Biederman609d7fa2006-10-02 02:17:15 -0700493 enum pid_type type;
494 struct pid *pid;
495 int ret = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700496
497 read_lock(&fown->lock);
Eric W. Biederman609d7fa2006-10-02 02:17:15 -0700498 type = fown->pid_type;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700499 pid = fown->pid;
500 if (!pid)
501 goto out_unlock_fown;
502
503 ret = 1;
504
505 read_lock(&tasklist_lock);
Eric W. Biederman609d7fa2006-10-02 02:17:15 -0700506 do_each_pid_task(pid, type, p) {
507 send_sigurg_to_task(p, fown);
508 } while_each_pid_task(pid, type, p);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700509 read_unlock(&tasklist_lock);
510 out_unlock_fown:
511 read_unlock(&fown->lock);
512 return ret;
513}
514
515static DEFINE_RWLOCK(fasync_lock);
Christoph Lametere18b8902006-12-06 20:33:20 -0800516static struct kmem_cache *fasync_cache __read_mostly;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700517
518/*
Jonathan Corbet76398422009-02-01 14:26:59 -0700519 * fasync_helper() is used by almost all character device drivers
Linus Torvalds1da177e2005-04-16 15:20:36 -0700520 * to set up the fasync queue. It returns negative on error, 0 if it did
521 * no changes and positive if it added/deleted the entry.
522 */
523int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp)
524{
525 struct fasync_struct *fa, **fp;
526 struct fasync_struct *new = NULL;
527 int result = 0;
528
529 if (on) {
Christoph Lametere94b1762006-12-06 20:33:17 -0800530 new = kmem_cache_alloc(fasync_cache, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700531 if (!new)
532 return -ENOMEM;
533 }
534 write_lock_irq(&fasync_lock);
535 for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
536 if (fa->fa_file == filp) {
537 if(on) {
538 fa->fa_fd = fd;
539 kmem_cache_free(fasync_cache, new);
540 } else {
541 *fp = fa->fa_next;
542 kmem_cache_free(fasync_cache, fa);
543 result = 1;
544 }
545 goto out;
546 }
547 }
548
549 if (on) {
550 new->magic = FASYNC_MAGIC;
551 new->fa_file = filp;
552 new->fa_fd = fd;
553 new->fa_next = *fapp;
554 *fapp = new;
555 result = 1;
556 }
557out:
Jonathan Corbet76398422009-02-01 14:26:59 -0700558 /* Fix up FASYNC bit while still holding fasync_lock */
559 spin_lock(&filp->f_lock);
560 if (on)
561 filp->f_flags |= FASYNC;
562 else
563 filp->f_flags &= ~FASYNC;
564 spin_unlock(&filp->f_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700565 write_unlock_irq(&fasync_lock);
566 return result;
567}
568
569EXPORT_SYMBOL(fasync_helper);
570
571void __kill_fasync(struct fasync_struct *fa, int sig, int band)
572{
573 while (fa) {
574 struct fown_struct * fown;
575 if (fa->magic != FASYNC_MAGIC) {
576 printk(KERN_ERR "kill_fasync: bad magic number in "
577 "fasync_struct!\n");
578 return;
579 }
580 fown = &fa->fa_file->f_owner;
581 /* Don't send SIGURG to processes which have not set a
582 queued signum: SIGURG has its own default signalling
583 mechanism. */
584 if (!(sig == SIGURG && fown->signum == 0))
585 send_sigio(fown, fa->fa_fd, band);
586 fa = fa->fa_next;
587 }
588}
589
590EXPORT_SYMBOL(__kill_fasync);
591
592void kill_fasync(struct fasync_struct **fp, int sig, int band)
593{
594 /* First a quick test without locking: usually
595 * the list is empty.
596 */
597 if (*fp) {
598 read_lock(&fasync_lock);
599 /* reread *fp after obtaining the lock */
600 __kill_fasync(*fp, sig, band);
601 read_unlock(&fasync_lock);
602 }
603}
604EXPORT_SYMBOL(kill_fasync);
605
606static int __init fasync_init(void)
607{
608 fasync_cache = kmem_cache_create("fasync_cache",
Paul Mundt20c2df82007-07-20 10:11:58 +0900609 sizeof(struct fasync_struct), 0, SLAB_PANIC, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700610 return 0;
611}
612
613module_init(fasync_init)