x86 mmiotrace: split set_page_presence()
[linux-2.6/mini2440.git] / fs / fcntl.c
blobbd215cc791da53eb9713063600a56ab3edb1c92a
1 /*
2 * linux/fs/fcntl.c
4 * Copyright (C) 1991, 1992 Linus Torvalds
5 */
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>
12 #include <linux/fdtable.h>
13 #include <linux/capability.h>
14 #include <linux/dnotify.h>
15 #include <linux/slab.h>
16 #include <linux/module.h>
17 #include <linux/security.h>
18 #include <linux/ptrace.h>
19 #include <linux/signal.h>
20 #include <linux/rcupdate.h>
21 #include <linux/pid_namespace.h>
22 #include <linux/smp_lock.h>
24 #include <asm/poll.h>
25 #include <asm/siginfo.h>
26 #include <asm/uaccess.h>
28 void set_close_on_exec(unsigned int fd, int flag)
30 struct files_struct *files = current->files;
31 struct fdtable *fdt;
32 spin_lock(&files->file_lock);
33 fdt = files_fdtable(files);
34 if (flag)
35 FD_SET(fd, fdt->close_on_exec);
36 else
37 FD_CLR(fd, fdt->close_on_exec);
38 spin_unlock(&files->file_lock);
41 static int get_close_on_exec(unsigned int fd)
43 struct files_struct *files = current->files;
44 struct fdtable *fdt;
45 int res;
46 rcu_read_lock();
47 fdt = files_fdtable(files);
48 res = FD_ISSET(fd, fdt->close_on_exec);
49 rcu_read_unlock();
50 return res;
53 SYSCALL_DEFINE3(dup3, unsigned int, oldfd, unsigned int, newfd, int, flags)
55 int err = -EBADF;
56 struct file * file, *tofree;
57 struct files_struct * files = current->files;
58 struct fdtable *fdt;
60 if ((flags & ~O_CLOEXEC) != 0)
61 return -EINVAL;
63 if (unlikely(oldfd == newfd))
64 return -EINVAL;
66 spin_lock(&files->file_lock);
67 err = expand_files(files, newfd);
68 file = fcheck(oldfd);
69 if (unlikely(!file))
70 goto Ebadf;
71 if (unlikely(err < 0)) {
72 if (err == -EMFILE)
73 goto Ebadf;
74 goto out_unlock;
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.
90 err = -EBUSY;
91 fdt = files_fdtable(files);
92 tofree = fdt->fd[newfd];
93 if (!tofree && FD_ISSET(newfd, fdt->open_fds))
94 goto out_unlock;
95 get_file(file);
96 rcu_assign_pointer(fdt->fd[newfd], file);
97 FD_SET(newfd, fdt->open_fds);
98 if (flags & O_CLOEXEC)
99 FD_SET(newfd, fdt->close_on_exec);
100 else
101 FD_CLR(newfd, fdt->close_on_exec);
102 spin_unlock(&files->file_lock);
104 if (tofree)
105 filp_close(tofree, files);
107 return newfd;
109 Ebadf:
110 err = -EBADF;
111 out_unlock:
112 spin_unlock(&files->file_lock);
113 return err;
116 SYSCALL_DEFINE2(dup2, unsigned int, oldfd, unsigned int, newfd)
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;
126 return sys_dup3(oldfd, newfd, 0);
129 SYSCALL_DEFINE1(dup, unsigned int, fildes)
131 int ret = -EBADF;
132 struct file *file = fget(fildes);
134 if (file) {
135 ret = get_unused_fd();
136 if (ret >= 0)
137 fd_install(ret, file);
138 else
139 fput(file);
141 return ret;
144 #define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | FASYNC | O_DIRECT | O_NOATIME)
146 static int setfl(int fd, struct file * filp, unsigned long arg)
148 struct inode * inode = filp->f_path.dentry->d_inode;
149 int error = 0;
152 * O_APPEND cannot be cleared if the file is marked as append-only
153 * and the file is open for write.
155 if (((arg ^ filp->f_flags) & O_APPEND) && IS_APPEND(inode))
156 return -EPERM;
158 /* O_NOATIME can only be set by the owner or superuser */
159 if ((arg & O_NOATIME) && !(filp->f_flags & O_NOATIME))
160 if (!is_owner_or_cap(inode))
161 return -EPERM;
163 /* required for strict SunOS emulation */
164 if (O_NONBLOCK != O_NDELAY)
165 if (arg & O_NDELAY)
166 arg |= O_NONBLOCK;
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;
174 if (filp->f_op && filp->f_op->check_flags)
175 error = filp->f_op->check_flags(arg);
176 if (error)
177 return error;
180 * We still need a lock here for now to keep multiple FASYNC calls
181 * from racing with each other.
183 lock_kernel();
184 if ((arg ^ filp->f_flags) & FASYNC) {
185 if (filp->f_op && filp->f_op->fasync) {
186 error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0);
187 if (error < 0)
188 goto out;
192 filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK);
193 out:
194 unlock_kernel();
195 return error;
198 static void f_modown(struct file *filp, struct pid *pid, enum pid_type type,
199 uid_t uid, uid_t euid, int force)
201 write_lock_irq(&filp->f_owner.lock);
202 if (force || !filp->f_owner.pid) {
203 put_pid(filp->f_owner.pid);
204 filp->f_owner.pid = get_pid(pid);
205 filp->f_owner.pid_type = type;
206 filp->f_owner.uid = uid;
207 filp->f_owner.euid = euid;
209 write_unlock_irq(&filp->f_owner.lock);
212 int __f_setown(struct file *filp, struct pid *pid, enum pid_type type,
213 int force)
215 const struct cred *cred = current_cred();
216 int err;
218 err = security_file_set_fowner(filp);
219 if (err)
220 return err;
222 f_modown(filp, pid, type, cred->uid, cred->euid, force);
223 return 0;
225 EXPORT_SYMBOL(__f_setown);
227 int f_setown(struct file *filp, unsigned long arg, int force)
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;
238 rcu_read_lock();
239 pid = find_vpid(who);
240 result = __f_setown(filp, pid, type, force);
241 rcu_read_unlock();
242 return result;
244 EXPORT_SYMBOL(f_setown);
246 void f_delown(struct file *filp)
248 f_modown(filp, NULL, PIDTYPE_PID, 0, 0, 1);
251 pid_t f_getown(struct file *filp)
253 pid_t pid;
254 read_lock(&filp->f_owner.lock);
255 pid = pid_vnr(filp->f_owner.pid);
256 if (filp->f_owner.pid_type == PIDTYPE_PGID)
257 pid = -pid;
258 read_unlock(&filp->f_owner.lock);
259 return pid;
262 static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
263 struct file *filp)
265 long err = -EINVAL;
267 switch (cmd) {
268 case F_DUPFD:
269 case F_DUPFD_CLOEXEC:
270 if (arg >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
271 break;
272 err = alloc_fd(arg, cmd == F_DUPFD_CLOEXEC ? O_CLOEXEC : 0);
273 if (err >= 0) {
274 get_file(filp);
275 fd_install(err, filp);
277 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:
296 err = fcntl_setlk(fd, filp, cmd, (struct flock __user *) arg);
297 break;
298 case F_GETOWN:
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.
306 err = f_getown(filp);
307 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. */
317 if (!valid_signal(arg)) {
318 break;
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;
335 return err;
338 SYSCALL_DEFINE3(fcntl, unsigned int, fd, unsigned int, cmd, unsigned long, arg)
340 struct file *filp;
341 long err = -EBADF;
343 filp = fget(fd);
344 if (!filp)
345 goto out;
347 err = security_file_fcntl(filp, cmd, arg);
348 if (err) {
349 fput(filp);
350 return err;
353 err = do_fcntl(fd, cmd, arg, filp);
355 fput(filp);
356 out:
357 return err;
360 #if BITS_PER_LONG == 32
361 SYSCALL_DEFINE3(fcntl64, unsigned int, fd, unsigned int, cmd,
362 unsigned long, arg)
364 struct file * filp;
365 long err;
367 err = -EBADF;
368 filp = fget(fd);
369 if (!filp)
370 goto out;
372 err = security_file_fcntl(filp, cmd, arg);
373 if (err) {
374 fput(filp);
375 return err;
377 err = -EBADF;
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:
385 err = fcntl_setlk64(fd, filp, cmd,
386 (struct flock64 __user *) arg);
387 break;
388 default:
389 err = do_fcntl(fd, cmd, arg, filp);
390 break;
392 fput(filp);
393 out:
394 return err;
396 #endif
398 /* Table to convert sigio signal codes into poll band bitmaps */
400 static const long band_table[NSIGPOLL] = {
401 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 */
409 static inline int sigio_perm(struct task_struct *p,
410 struct fown_struct *fown, int sig)
412 const struct cred *cred;
413 int ret;
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;
425 static void send_sigio_to_task(struct task_struct *p,
426 struct fown_struct *fown,
427 int fd,
428 int reason)
430 if (!sigio_perm(p, fown, fown->signum))
431 return;
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. */
448 BUG_ON((reason & __SI_MASK) != __SI_POLL);
449 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;
454 if (!group_send_sig_info(fown->signum, &si, p))
455 break;
456 /* fall-through: fall back on the old plain SIGIO signal */
457 case 0:
458 group_send_sig_info(SIGIO, SEND_SIG_PRIV, p);
462 void send_sigio(struct fown_struct *fown, int fd, int band)
464 struct task_struct *p;
465 enum pid_type type;
466 struct pid *pid;
468 read_lock(&fown->lock);
469 type = fown->pid_type;
470 pid = fown->pid;
471 if (!pid)
472 goto out_unlock_fown;
474 read_lock(&tasklist_lock);
475 do_each_pid_task(pid, type, p) {
476 send_sigio_to_task(p, fown, fd, band);
477 } while_each_pid_task(pid, type, p);
478 read_unlock(&tasklist_lock);
479 out_unlock_fown:
480 read_unlock(&fown->lock);
483 static void send_sigurg_to_task(struct task_struct *p,
484 struct fown_struct *fown)
486 if (sigio_perm(p, fown, SIGURG))
487 group_send_sig_info(SIGURG, SEND_SIG_PRIV, p);
490 int send_sigurg(struct fown_struct *fown)
492 struct task_struct *p;
493 enum pid_type type;
494 struct pid *pid;
495 int ret = 0;
497 read_lock(&fown->lock);
498 type = fown->pid_type;
499 pid = fown->pid;
500 if (!pid)
501 goto out_unlock_fown;
503 ret = 1;
505 read_lock(&tasklist_lock);
506 do_each_pid_task(pid, type, p) {
507 send_sigurg_to_task(p, fown);
508 } while_each_pid_task(pid, type, p);
509 read_unlock(&tasklist_lock);
510 out_unlock_fown:
511 read_unlock(&fown->lock);
512 return ret;
515 static DEFINE_RWLOCK(fasync_lock);
516 static struct kmem_cache *fasync_cache __read_mostly;
519 * fasync_helper() is used by some character device drivers (mainly mice)
520 * 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.
523 int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp)
525 struct fasync_struct *fa, **fp;
526 struct fasync_struct *new = NULL;
527 int result = 0;
529 if (on) {
530 new = kmem_cache_alloc(fasync_cache, GFP_KERNEL);
531 if (!new)
532 return -ENOMEM;
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;
545 goto out;
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;
557 out:
558 write_unlock_irq(&fasync_lock);
559 return result;
562 EXPORT_SYMBOL(fasync_helper);
564 void __kill_fasync(struct fasync_struct *fa, int sig, int band)
566 while (fa) {
567 struct fown_struct * fown;
568 if (fa->magic != FASYNC_MAGIC) {
569 printk(KERN_ERR "kill_fasync: bad magic number in "
570 "fasync_struct!\n");
571 return;
573 fown = &fa->fa_file->f_owner;
574 /* Don't send SIGURG to processes which have not set a
575 queued signum: SIGURG has its own default signalling
576 mechanism. */
577 if (!(sig == SIGURG && fown->signum == 0))
578 send_sigio(fown, fa->fa_fd, band);
579 fa = fa->fa_next;
583 EXPORT_SYMBOL(__kill_fasync);
585 void kill_fasync(struct fasync_struct **fp, int sig, int band)
587 /* First a quick test without locking: usually
588 * the list is empty.
590 if (*fp) {
591 read_lock(&fasync_lock);
592 /* reread *fp after obtaining the lock */
593 __kill_fasync(*fp, sig, band);
594 read_unlock(&fasync_lock);
597 EXPORT_SYMBOL(kill_fasync);
599 static int __init fasync_init(void)
601 fasync_cache = kmem_cache_create("fasync_cache",
602 sizeof(struct fasync_struct), 0, SLAB_PANIC, NULL);
603 return 0;
606 module_init(fasync_init)