4 * Copyright (C) 1991, 1992 Linus Torvalds
7 #include <linux/syscalls.h>
8 #include <linux/init.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>
24 #include <asm/siginfo.h>
25 #include <asm/uaccess.h>
27 void set_close_on_exec(unsigned int fd, int flag)
29 struct files_struct *files = current->files;
31 spin_lock(&files->file_lock);
32 fdt = files_fdtable(files);
34 FD_SET(fd, fdt->close_on_exec);
36 FD_CLR(fd, fdt->close_on_exec);
37 spin_unlock(&files->file_lock);
40 static int get_close_on_exec(unsigned int fd)
42 struct files_struct *files = current->files;
46 fdt = files_fdtable(files);
47 res = FD_ISSET(fd, fdt->close_on_exec);
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.
58 static int locate_fd(unsigned int orig_start, int cloexec)
60 struct files_struct *files = current->files;
66 spin_lock(&files->file_lock);
69 if (orig_start >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
73 fdt = files_fdtable(files);
75 * Someone might have closed fd's in the range
76 * orig_start..fdt->next_fd
79 if (start < files->next_fd)
80 start = files->next_fd;
83 if (start < fdt->max_fds)
84 newfd = find_next_zero_bit(fdt->open_fds->fds_bits,
88 if (newfd >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
91 error = expand_files(files, newfd);
96 * If we needed to expand the fs array we
97 * might have blocked - try again.
102 if (start <= files->next_fd)
103 files->next_fd = newfd + 1;
105 FD_SET(newfd, fdt->open_fds);
107 FD_SET(newfd, fdt->close_on_exec);
109 FD_CLR(newfd, fdt->close_on_exec);
113 spin_unlock(&files->file_lock);
117 static int dupfd(struct file *file, unsigned int start, int cloexec)
119 int fd = locate_fd(start, cloexec);
121 fd_install(fd, file);
128 asmlinkage long sys_dup3(unsigned int oldfd, unsigned int newfd, int flags)
131 struct file * file, *tofree;
132 struct files_struct * files = current->files;
135 if ((flags & ~O_CLOEXEC) != 0)
138 if (unlikely(oldfd == newfd))
141 spin_lock(&files->file_lock);
142 if (!(file = fcheck(oldfd)))
144 if (newfd >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
146 get_file(file); /* We are now finished with oldfd */
148 err = expand_files(files, newfd);
152 /* To avoid races with open() and dup(), we will mark the fd as
153 * in-use in the open-file bitmap throughout the entire dup2()
154 * process. This is quite safe: do_close() uses the fd array
155 * entry, not the bitmap, to decide what work needs to be
157 /* Doesn't work. open() might be there first. --AV */
159 /* Yes. It's a race. In user space. Nothing sane to do */
161 fdt = files_fdtable(files);
162 tofree = fdt->fd[newfd];
163 if (!tofree && FD_ISSET(newfd, fdt->open_fds))
166 rcu_assign_pointer(fdt->fd[newfd], file);
167 FD_SET(newfd, fdt->open_fds);
168 if (flags & O_CLOEXEC)
169 FD_SET(newfd, fdt->close_on_exec);
171 FD_CLR(newfd, fdt->close_on_exec);
172 spin_unlock(&files->file_lock);
175 filp_close(tofree, files);
180 spin_unlock(&files->file_lock);
184 spin_unlock(&files->file_lock);
189 asmlinkage long sys_dup2(unsigned int oldfd, unsigned int newfd)
191 if (unlikely(newfd == oldfd)) { /* corner case */
192 struct files_struct *files = current->files;
194 if (!fcheck_files(files, oldfd))
199 return sys_dup3(oldfd, newfd, 0);
202 asmlinkage long sys_dup(unsigned int fildes)
205 struct file * file = fget(fildes);
208 ret = dupfd(file, 0, 0);
212 #define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | FASYNC | O_DIRECT | O_NOATIME)
214 static int setfl(int fd, struct file * filp, unsigned long arg)
216 struct inode * inode = filp->f_path.dentry->d_inode;
220 * O_APPEND cannot be cleared if the file is marked as append-only
221 * and the file is open for write.
223 if (((arg ^ filp->f_flags) & O_APPEND) && IS_APPEND(inode))
226 /* O_NOATIME can only be set by the owner or superuser */
227 if ((arg & O_NOATIME) && !(filp->f_flags & O_NOATIME))
228 if (!is_owner_or_cap(inode))
231 /* required for strict SunOS emulation */
232 if (O_NONBLOCK != O_NDELAY)
236 if (arg & O_DIRECT) {
237 if (!filp->f_mapping || !filp->f_mapping->a_ops ||
238 !filp->f_mapping->a_ops->direct_IO)
242 if (filp->f_op && filp->f_op->check_flags)
243 error = filp->f_op->check_flags(arg);
247 if ((arg ^ filp->f_flags) & FASYNC) {
248 if (filp->f_op && filp->f_op->fasync) {
249 error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0);
255 filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK);
260 static void f_modown(struct file *filp, struct pid *pid, enum pid_type type,
261 uid_t uid, uid_t euid, int force)
263 write_lock_irq(&filp->f_owner.lock);
264 if (force || !filp->f_owner.pid) {
265 put_pid(filp->f_owner.pid);
266 filp->f_owner.pid = get_pid(pid);
267 filp->f_owner.pid_type = type;
268 filp->f_owner.uid = uid;
269 filp->f_owner.euid = euid;
271 write_unlock_irq(&filp->f_owner.lock);
274 int __f_setown(struct file *filp, struct pid *pid, enum pid_type type,
279 err = security_file_set_fowner(filp);
283 f_modown(filp, pid, type, current->uid, current->euid, force);
286 EXPORT_SYMBOL(__f_setown);
288 int f_setown(struct file *filp, unsigned long arg, int force)
300 pid = find_vpid(who);
301 result = __f_setown(filp, pid, type, force);
305 EXPORT_SYMBOL(f_setown);
307 void f_delown(struct file *filp)
309 f_modown(filp, NULL, PIDTYPE_PID, 0, 0, 1);
312 pid_t f_getown(struct file *filp)
315 read_lock(&filp->f_owner.lock);
316 pid = pid_vnr(filp->f_owner.pid);
317 if (filp->f_owner.pid_type == PIDTYPE_PGID)
319 read_unlock(&filp->f_owner.lock);
323 static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
330 case F_DUPFD_CLOEXEC:
332 err = dupfd(filp, arg, cmd == F_DUPFD_CLOEXEC);
335 err = get_close_on_exec(fd) ? FD_CLOEXEC : 0;
339 set_close_on_exec(fd, arg & FD_CLOEXEC);
345 err = setfl(fd, filp, arg);
348 err = fcntl_getlk(filp, (struct flock __user *) arg);
352 err = fcntl_setlk(fd, filp, cmd, (struct flock __user *) arg);
356 * XXX If f_owner is a process group, the
357 * negative return value will get converted
358 * into an error. Oops. If we keep the
359 * current syscall conventions, the only way
360 * to fix this will be in libc.
362 err = f_getown(filp);
363 force_successful_syscall_return();
366 err = f_setown(filp, arg, 1);
369 err = filp->f_owner.signum;
372 /* arg == 0 restores default behaviour. */
373 if (!valid_signal(arg)) {
377 filp->f_owner.signum = arg;
380 err = fcntl_getlease(filp);
383 err = fcntl_setlease(fd, filp, arg);
386 err = fcntl_dirnotify(fd, filp, arg);
394 asmlinkage long sys_fcntl(unsigned int fd, unsigned int cmd, unsigned long arg)
403 err = security_file_fcntl(filp, cmd, arg);
409 err = do_fcntl(fd, cmd, arg, filp);
416 #if BITS_PER_LONG == 32
417 asmlinkage long sys_fcntl64(unsigned int fd, unsigned int cmd, unsigned long arg)
427 err = security_file_fcntl(filp, cmd, arg);
436 err = fcntl_getlk64(filp, (struct flock64 __user *) arg);
440 err = fcntl_setlk64(fd, filp, cmd,
441 (struct flock64 __user *) arg);
444 err = do_fcntl(fd, cmd, arg, filp);
453 /* Table to convert sigio signal codes into poll band bitmaps */
455 static const long band_table[NSIGPOLL] = {
456 POLLIN | POLLRDNORM, /* POLL_IN */
457 POLLOUT | POLLWRNORM | POLLWRBAND, /* POLL_OUT */
458 POLLIN | POLLRDNORM | POLLMSG, /* POLL_MSG */
459 POLLERR, /* POLL_ERR */
460 POLLPRI | POLLRDBAND, /* POLL_PRI */
461 POLLHUP | POLLERR /* POLL_HUP */
464 static inline int sigio_perm(struct task_struct *p,
465 struct fown_struct *fown, int sig)
467 return (((fown->euid == 0) ||
468 (fown->euid == p->suid) || (fown->euid == p->uid) ||
469 (fown->uid == p->suid) || (fown->uid == p->uid)) &&
470 !security_file_send_sigiotask(p, fown, sig));
473 static void send_sigio_to_task(struct task_struct *p,
474 struct fown_struct *fown,
478 if (!sigio_perm(p, fown, fown->signum))
481 switch (fown->signum) {
484 /* Queue a rt signal with the appropriate fd as its
485 value. We use SI_SIGIO as the source, not
486 SI_KERNEL, since kernel signals always get
487 delivered even if we can't queue. Failure to
488 queue in this case _should_ be reported; we fall
489 back to SIGIO in that case. --sct */
490 si.si_signo = fown->signum;
493 /* Make sure we are called with one of the POLL_*
494 reasons, otherwise we could leak kernel stack into
496 BUG_ON((reason & __SI_MASK) != __SI_POLL);
497 if (reason - POLL_IN >= NSIGPOLL)
500 si.si_band = band_table[reason - POLL_IN];
502 if (!group_send_sig_info(fown->signum, &si, p))
504 /* fall-through: fall back on the old plain SIGIO signal */
506 group_send_sig_info(SIGIO, SEND_SIG_PRIV, p);
510 void send_sigio(struct fown_struct *fown, int fd, int band)
512 struct task_struct *p;
516 read_lock(&fown->lock);
517 type = fown->pid_type;
520 goto out_unlock_fown;
522 read_lock(&tasklist_lock);
523 do_each_pid_task(pid, type, p) {
524 send_sigio_to_task(p, fown, fd, band);
525 } while_each_pid_task(pid, type, p);
526 read_unlock(&tasklist_lock);
528 read_unlock(&fown->lock);
531 static void send_sigurg_to_task(struct task_struct *p,
532 struct fown_struct *fown)
534 if (sigio_perm(p, fown, SIGURG))
535 group_send_sig_info(SIGURG, SEND_SIG_PRIV, p);
538 int send_sigurg(struct fown_struct *fown)
540 struct task_struct *p;
545 read_lock(&fown->lock);
546 type = fown->pid_type;
549 goto out_unlock_fown;
553 read_lock(&tasklist_lock);
554 do_each_pid_task(pid, type, p) {
555 send_sigurg_to_task(p, fown);
556 } while_each_pid_task(pid, type, p);
557 read_unlock(&tasklist_lock);
559 read_unlock(&fown->lock);
563 static DEFINE_RWLOCK(fasync_lock);
564 static struct kmem_cache *fasync_cache __read_mostly;
567 * fasync_helper() is used by some character device drivers (mainly mice)
568 * to set up the fasync queue. It returns negative on error, 0 if it did
569 * no changes and positive if it added/deleted the entry.
571 int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp)
573 struct fasync_struct *fa, **fp;
574 struct fasync_struct *new = NULL;
578 new = kmem_cache_alloc(fasync_cache, GFP_KERNEL);
582 write_lock_irq(&fasync_lock);
583 for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
584 if (fa->fa_file == filp) {
587 kmem_cache_free(fasync_cache, new);
590 kmem_cache_free(fasync_cache, fa);
598 new->magic = FASYNC_MAGIC;
601 new->fa_next = *fapp;
606 write_unlock_irq(&fasync_lock);
610 EXPORT_SYMBOL(fasync_helper);
612 void __kill_fasync(struct fasync_struct *fa, int sig, int band)
615 struct fown_struct * fown;
616 if (fa->magic != FASYNC_MAGIC) {
617 printk(KERN_ERR "kill_fasync: bad magic number in "
621 fown = &fa->fa_file->f_owner;
622 /* Don't send SIGURG to processes which have not set a
623 queued signum: SIGURG has its own default signalling
625 if (!(sig == SIGURG && fown->signum == 0))
626 send_sigio(fown, fa->fa_fd, band);
631 EXPORT_SYMBOL(__kill_fasync);
633 void kill_fasync(struct fasync_struct **fp, int sig, int band)
635 /* First a quick test without locking: usually
639 read_lock(&fasync_lock);
640 /* reread *fp after obtaining the lock */
641 __kill_fasync(*fp, sig, band);
642 read_unlock(&fasync_lock);
645 EXPORT_SYMBOL(kill_fasync);
647 static int __init fasync_init(void)
649 fasync_cache = kmem_cache_create("fasync_cache",
650 sizeof(struct fasync_struct), 0, SLAB_PANIC, NULL);
654 module_init(fasync_init)