4 * Copyright (C) 1991, 1992 Linus Torvalds
7 #include <linux/init.h>
10 #include <linux/file.h>
11 #include <linux/dnotify.h>
12 #include <linux/smp_lock.h>
13 #include <linux/slab.h>
14 #include <linux/module.h>
15 #include <linux/security.h>
16 #include <linux/ptrace.h>
17 #include <linux/vs_limit.h>
20 #include <asm/siginfo.h>
21 #include <asm/uaccess.h>
23 void fastcall set_close_on_exec(unsigned int fd, int flag)
25 struct files_struct *files = current->files;
26 spin_lock(&files->file_lock);
28 FD_SET(fd, files->close_on_exec);
30 FD_CLR(fd, files->close_on_exec);
31 spin_unlock(&files->file_lock);
34 static inline int get_close_on_exec(unsigned int fd)
36 struct files_struct *files = current->files;
38 spin_lock(&files->file_lock);
39 res = FD_ISSET(fd, files->close_on_exec);
40 spin_unlock(&files->file_lock);
45 /* Expand files. Return <0 on error; 0 nothing done; 1 files expanded,
46 * we may have blocked.
48 * Should be called with the files->file_lock spinlock held for write.
50 static int expand_files(struct files_struct *files, int nr)
54 printk (KERN_ERR "%s %d: nr = %d\n", __FUNCTION__, current->pid, nr);
57 if (nr >= files->max_fdset) {
59 if ((err = expand_fdset(files, nr)))
62 if (nr >= files->max_fds) {
64 if ((err = expand_fd_array(files, nr)))
71 printk (KERN_ERR "%s %d: return %d\n", __FUNCTION__, current->pid, err);
77 * locate_fd finds a free file descriptor in the open_fds fdset,
78 * expanding the fd arrays if necessary. Must be called with the
79 * file_lock held for write.
82 static int locate_fd(struct files_struct *files,
83 struct file *file, unsigned int orig_start)
90 if (orig_start >= current->rlim[RLIMIT_NOFILE].rlim_cur)
95 * Someone might have closed fd's in the range
96 * orig_start..files->next_fd
99 if (start < files->next_fd)
100 start = files->next_fd;
103 if (start < files->max_fdset) {
104 newfd = find_next_zero_bit(files->open_fds->fds_bits,
105 files->max_fdset, start);
109 if (newfd >= current->rlim[RLIMIT_NOFILE].rlim_cur)
111 if (!vx_files_avail(1))
114 error = expand_files(files, newfd);
119 * If we needed to expand the fs array we
120 * might have blocked - try again.
125 if (start <= files->next_fd)
126 files->next_fd = newfd + 1;
134 int dupfd(struct file *file, unsigned int start)
136 struct files_struct * files = current->files;
139 spin_lock(&files->file_lock);
140 fd = locate_fd(files, file, start);
142 FD_SET(fd, files->open_fds);
143 FD_CLR(fd, files->close_on_exec);
144 spin_unlock(&files->file_lock);
146 fd_install(fd, file);
148 spin_unlock(&files->file_lock);
155 EXPORT_SYMBOL_GPL(dupfd);
157 asmlinkage long sys_dup2(unsigned int oldfd, unsigned int newfd)
160 struct file * file, *tofree;
161 struct files_struct * files = current->files;
163 spin_lock(&files->file_lock);
164 if (!(file = fcheck(oldfd)))
170 if (newfd >= current->rlim[RLIMIT_NOFILE].rlim_cur)
172 get_file(file); /* We are now finished with oldfd */
174 err = expand_files(files, newfd);
178 /* To avoid races with open() and dup(), we will mark the fd as
179 * in-use in the open-file bitmap throughout the entire dup2()
180 * process. This is quite safe: do_close() uses the fd array
181 * entry, not the bitmap, to decide what work needs to be
183 /* Doesn't work. open() might be there first. --AV */
185 /* Yes. It's a race. In user space. Nothing sane to do */
187 tofree = files->fd[newfd];
188 if (!tofree && FD_ISSET(newfd, files->open_fds))
191 files->fd[newfd] = file;
192 FD_SET(newfd, files->open_fds);
193 FD_CLR(newfd, files->close_on_exec);
194 spin_unlock(&files->file_lock);
195 vx_openfd_inc(newfd);
198 filp_close(tofree, files);
203 spin_unlock(&files->file_lock);
207 spin_unlock(&files->file_lock);
212 asmlinkage long sys_dup(unsigned int fildes)
215 struct file * file = fget(fildes);
218 ret = dupfd(file, 0);
222 #define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | FASYNC | O_DIRECT)
224 static int setfl(int fd, struct file * filp, unsigned long arg)
226 struct inode * inode = filp->f_dentry->d_inode;
229 /* O_APPEND cannot be cleared if the file is marked as append-only */
230 if (!(arg & O_APPEND) && IS_APPEND(inode))
233 /* required for strict SunOS emulation */
234 if (O_NONBLOCK != O_NDELAY)
238 if (arg & O_DIRECT) {
239 if (!filp->f_mapping || !filp->f_mapping->a_ops ||
240 !filp->f_mapping->a_ops->direct_IO)
245 if ((arg ^ filp->f_flags) & FASYNC) {
246 if (filp->f_op && filp->f_op->fasync) {
247 error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0);
253 filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK);
259 static void f_modown(struct file *filp, unsigned long pid,
260 uid_t uid, uid_t euid, int force)
262 write_lock_irq(&filp->f_owner.lock);
263 if (force || !filp->f_owner.pid) {
264 filp->f_owner.pid = pid;
265 filp->f_owner.uid = uid;
266 filp->f_owner.euid = euid;
268 write_unlock_irq(&filp->f_owner.lock);
271 int f_setown(struct file *filp, unsigned long arg, int force)
275 err = security_file_set_fowner(filp);
279 f_modown(filp, arg, current->uid, current->euid, force);
283 EXPORT_SYMBOL(f_setown);
285 void f_delown(struct file *filp)
287 f_modown(filp, 0, 0, 0, 1);
290 EXPORT_SYMBOL(f_delown);
292 long generic_file_fcntl(int fd, unsigned int cmd,
293 unsigned long arg, struct file *filp)
300 err = dupfd(filp, arg);
303 err = get_close_on_exec(fd) ? FD_CLOEXEC : 0;
307 set_close_on_exec(fd, arg & FD_CLOEXEC);
313 err = setfl(fd, filp, arg);
316 err = fcntl_getlk(filp, (struct flock __user *) arg);
320 err = fcntl_setlk(filp, cmd, (struct flock __user *) arg);
324 * XXX If f_owner is a process group, the
325 * negative return value will get converted
326 * into an error. Oops. If we keep the
327 * current syscall conventions, the only way
328 * to fix this will be in libc.
330 err = filp->f_owner.pid;
331 force_successful_syscall_return();
334 err = f_setown(filp, arg, 1);
337 err = filp->f_owner.signum;
340 /* arg == 0 restores default behaviour. */
341 if (arg < 0 || arg > _NSIG) {
345 filp->f_owner.signum = arg;
348 err = fcntl_getlease(filp);
351 err = fcntl_setlease(fd, filp, arg);
354 err = fcntl_dirnotify(fd, filp, arg);
361 EXPORT_SYMBOL(generic_file_fcntl);
363 static long do_fcntl(int fd, unsigned int cmd,
364 unsigned long arg, struct file *filp)
366 if (filp->f_op && filp->f_op->fcntl)
367 return filp->f_op->fcntl(fd, cmd, arg, filp);
368 return generic_file_fcntl(fd, cmd, arg, filp);
371 asmlinkage long sys_fcntl(int fd, unsigned int cmd, unsigned long arg)
380 err = security_file_fcntl(filp, cmd, arg);
386 err = do_fcntl(fd, cmd, arg, filp);
393 #if BITS_PER_LONG == 32
394 asmlinkage long sys_fcntl64(unsigned int fd, unsigned int cmd, unsigned long arg)
404 err = security_file_fcntl(filp, cmd, arg);
413 err = fcntl_getlk64(filp, (struct flock64 __user *) arg);
417 err = fcntl_setlk64(filp, cmd, (struct flock64 __user *) arg);
420 err = do_fcntl(fd, cmd, arg, filp);
429 /* Table to convert sigio signal codes into poll band bitmaps */
431 static long band_table[NSIGPOLL] = {
432 POLLIN | POLLRDNORM, /* POLL_IN */
433 POLLOUT | POLLWRNORM | POLLWRBAND, /* POLL_OUT */
434 POLLIN | POLLRDNORM | POLLMSG, /* POLL_MSG */
435 POLLERR, /* POLL_ERR */
436 POLLPRI | POLLRDBAND, /* POLL_PRI */
437 POLLHUP | POLLERR /* POLL_HUP */
440 static inline int sigio_perm(struct task_struct *p,
441 struct fown_struct *fown)
443 return ((fown->euid == 0) ||
444 (fown->euid == p->suid) || (fown->euid == p->uid) ||
445 (fown->uid == p->suid) || (fown->uid == p->uid));
448 static void send_sigio_to_task(struct task_struct *p,
449 struct fown_struct *fown,
453 if (!sigio_perm(p, fown))
456 if (security_file_send_sigiotask(p, fown, fd, reason))
459 switch (fown->signum) {
462 /* Queue a rt signal with the appropriate fd as its
463 value. We use SI_SIGIO as the source, not
464 SI_KERNEL, since kernel signals always get
465 delivered even if we can't queue. Failure to
466 queue in this case _should_ be reported; we fall
467 back to SIGIO in that case. --sct */
468 si.si_signo = fown->signum;
471 /* Make sure we are called with one of the POLL_*
472 reasons, otherwise we could leak kernel stack into
474 if ((reason & __SI_MASK) != __SI_POLL)
476 if (reason - POLL_IN >= NSIGPOLL)
479 si.si_band = band_table[reason - POLL_IN];
481 if (!send_sig_info(fown->signum, &si, p))
483 /* fall-through: fall back on the old plain SIGIO signal */
485 send_group_sig_info(SIGIO, SEND_SIG_PRIV, p);
489 void send_sigio(struct fown_struct *fown, int fd, int band)
491 struct task_struct *p;
494 read_lock(&fown->lock);
497 goto out_unlock_fown;
499 read_lock(&tasklist_lock);
501 p = find_task_by_pid(pid);
503 send_sigio_to_task(p, fown, fd, band);
508 for_each_task_pid(-pid, PIDTYPE_PGID, p, l, pidptr) {
509 send_sigio_to_task(p, fown, fd, band);
512 read_unlock(&tasklist_lock);
514 read_unlock(&fown->lock);
517 static void send_sigurg_to_task(struct task_struct *p,
518 struct fown_struct *fown)
520 if (sigio_perm(p, fown))
521 send_group_sig_info(SIGURG, SEND_SIG_PRIV, p);
524 int send_sigurg(struct fown_struct *fown)
526 struct task_struct *p;
529 read_lock(&fown->lock);
532 goto out_unlock_fown;
536 read_lock(&tasklist_lock);
538 p = find_task_by_pid(pid);
540 send_sigurg_to_task(p, fown);
545 for_each_task_pid(-pid, PIDTYPE_PGID, p, l, pidptr) {
546 send_sigurg_to_task(p, fown);
549 read_unlock(&tasklist_lock);
551 read_unlock(&fown->lock);
555 static rwlock_t fasync_lock = RW_LOCK_UNLOCKED;
556 static kmem_cache_t *fasync_cache;
559 * fasync_helper() is used by some character device drivers (mainly mice)
560 * to set up the fasync queue. It returns negative on error, 0 if it did
561 * no changes and positive if it added/deleted the entry.
563 int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp)
565 struct fasync_struct *fa, **fp;
566 struct fasync_struct *new = NULL;
570 new = kmem_cache_alloc(fasync_cache, SLAB_KERNEL);
574 write_lock_irq(&fasync_lock);
575 for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
576 if (fa->fa_file == filp) {
579 kmem_cache_free(fasync_cache, new);
582 kmem_cache_free(fasync_cache, fa);
590 new->magic = FASYNC_MAGIC;
593 new->fa_next = *fapp;
598 write_unlock_irq(&fasync_lock);
602 EXPORT_SYMBOL(fasync_helper);
604 void __kill_fasync(struct fasync_struct *fa, int sig, int band)
607 struct fown_struct * fown;
608 if (fa->magic != FASYNC_MAGIC) {
609 printk(KERN_ERR "kill_fasync: bad magic number in "
613 fown = &fa->fa_file->f_owner;
614 /* Don't send SIGURG to processes which have not set a
615 queued signum: SIGURG has its own default signalling
617 if (!(sig == SIGURG && fown->signum == 0))
618 send_sigio(fown, fa->fa_fd, band);
623 EXPORT_SYMBOL(__kill_fasync);
625 void kill_fasync(struct fasync_struct **fp, int sig, int band)
627 /* First a quick test without locking: usually
631 read_lock(&fasync_lock);
632 /* reread *fp after obtaining the lock */
633 __kill_fasync(*fp, sig, band);
634 read_unlock(&fasync_lock);
637 EXPORT_SYMBOL(kill_fasync);
639 static int __init fasync_init(void)
641 fasync_cache = kmem_cache_create("fasync_cache",
642 sizeof(struct fasync_struct), 0, SLAB_PANIC, NULL, NULL);
646 module_init(fasync_init)