[net-next-2.6.git] / fs / fcntl.c

/*
 *  linux/fs/fcntl.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 */

#include <linux/syscalls.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/fdtable.h>
#include <linux/capability.h>
#include <linux/dnotify.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/security.h>
#include <linux/ptrace.h>
#include <linux/signal.h>
#include <linux/rcupdate.h>
#include <linux/pid_namespace.h>

#include <asm/poll.h>
#include <asm/siginfo.h>
#include <asm/uaccess.h>

void set_close_on_exec(unsigned int fd, int flag)
{
	struct files_struct *files = current->files;
	struct fdtable *fdt;
	spin_lock(&files->file_lock);
	fdt = files_fdtable(files);
	if (flag)
		FD_SET(fd, fdt->close_on_exec);
	else
		FD_CLR(fd, fdt->close_on_exec);
	spin_unlock(&files->file_lock);
}

static int get_close_on_exec(unsigned int fd)
{
	struct files_struct *files = current->files;
	struct fdtable *fdt;
	int res;
	rcu_read_lock();
	fdt = files_fdtable(files);
	res = FD_ISSET(fd, fdt->close_on_exec);
	rcu_read_unlock();
	return res;
}

/*
 * locate_fd finds a free file descriptor in the open_fds fdset,
 * expanding the fd arrays if necessary.  Must be called with the
 * file_lock held for write.
 */

static int locate_fd(unsigned int orig_start, int cloexec)
{
	struct files_struct *files = current->files;
	unsigned int newfd;
	unsigned int start;
	int error;
	struct fdtable *fdt;

	spin_lock(&files->file_lock);

	error = -EINVAL;
	if (orig_start >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
		goto out;

repeat:
	fdt = files_fdtable(files);
	/*
	 * Someone might have closed fd's in the range
	 * orig_start..fdt->next_fd
	 */
	start = orig_start;
	if (start < files->next_fd)
		start = files->next_fd;

	newfd = start;
	if (start < fdt->max_fds)
		newfd = find_next_zero_bit(fdt->open_fds->fds_bits,
					   fdt->max_fds, start);
	
	error = -EMFILE;
	if (newfd >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
		goto out;

	error = expand_files(files, newfd);
	if (error < 0)
		goto out;

	/*
	 * If we needed to expand the fs array we
	 * might have blocked - try again.
	 */
	if (error)
		goto repeat;

	if (start <= files->next_fd)
		files->next_fd = newfd + 1;

	FD_SET(newfd, fdt->open_fds);
	if (cloexec)
		FD_SET(newfd, fdt->close_on_exec);
	else
		FD_CLR(newfd, fdt->close_on_exec);
	error = newfd;

out:
	spin_unlock(&files->file_lock);
	return error;
}

static int dupfd(struct file *file, unsigned int start, int cloexec)
{
	int fd = locate_fd(start, cloexec);
	if (fd >= 0)
		fd_install(fd, file);
	else
		fput(file);

	return fd;
}

asmlinkage long sys_dup2(unsigned int oldfd, unsigned int newfd)
{
	int err = -EBADF;
	struct file * file, *tofree;
	struct files_struct * files = current->files;
	struct fdtable *fdt;

	spin_lock(&files->file_lock);
	if (!(file = fcheck(oldfd)))
		goto out_unlock;
	err = newfd;
	if (newfd == oldfd)
		goto out_unlock;
	err = -EBADF;
	if (newfd >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
		goto out_unlock;
	get_file(file);			/* We are now finished with oldfd */

	err = expand_files(files, newfd);
	if (err < 0)
		goto out_fput;

	/* To avoid races with open() and dup(), we will mark the fd as
	 * in-use in the open-file bitmap throughout the entire dup2()
	 * process.  This is quite safe: do_close() uses the fd array
	 * entry, not the bitmap, to decide what work needs to be
	 * done.  --sct */
	/* Doesn't work. open() might be there first. --AV */

	/* Yes. It's a race. In user space. Nothing sane to do */
	err = -EBUSY;
	fdt = files_fdtable(files);
	tofree = fdt->fd[newfd];
	if (!tofree && FD_ISSET(newfd, fdt->open_fds))
		goto out_fput;

	rcu_assign_pointer(fdt->fd[newfd], file);
	FD_SET(newfd, fdt->open_fds);
	FD_CLR(newfd, fdt->close_on_exec);
	spin_unlock(&files->file_lock);

	if (tofree)
		filp_close(tofree, files);
	err = newfd;
out:
	return err;
out_unlock:
	spin_unlock(&files->file_lock);
	goto out;

out_fput:
	spin_unlock(&files->file_lock);
	fput(file);
	goto out;
}

asmlinkage long sys_dup(unsigned int fildes)
{
	int ret = -EBADF;
	struct file * file = fget(fildes);

	if (file)
		ret = dupfd(file, 0, 0);
	return ret;
}

#define SETFL_MASK (O_APPEND | O_NONBLOCK | O_NDELAY | FASYNC | O_DIRECT | O_NOATIME)

static int setfl(int fd, struct file * filp, unsigned long arg)
{
	struct inode * inode = filp->f_path.dentry->d_inode;
	int error = 0;

	/*
	 * O_APPEND cannot be cleared if the file is marked as append-only
	 * and the file is open for write.
	 */
	if (((arg ^ filp->f_flags) & O_APPEND) && IS_APPEND(inode))
		return -EPERM;

	/* O_NOATIME can only be set by the owner or superuser */
	if ((arg & O_NOATIME) && !(filp->f_flags & O_NOATIME))
		if (!is_owner_or_cap(inode))
			return -EPERM;

	/* required for strict SunOS emulation */
	if (O_NONBLOCK != O_NDELAY)
	       if (arg & O_NDELAY)
		   arg |= O_NONBLOCK;

	if (arg & O_DIRECT) {
		if (!filp->f_mapping || !filp->f_mapping->a_ops ||
			!filp->f_mapping->a_ops->direct_IO)
				return -EINVAL;
	}

	if (filp->f_op && filp->f_op->check_flags)
		error = filp->f_op->check_flags(arg);
	if (error)
		return error;

	if ((arg ^ filp->f_flags) & FASYNC) {
		if (filp->f_op && filp->f_op->fasync) {
			error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0);
			if (error < 0)
				goto out;
		}
	}

	filp->f_flags = (arg & SETFL_MASK) | (filp->f_flags & ~SETFL_MASK);
 out:
	return error;
}

static void f_modown(struct file *filp, struct pid *pid, enum pid_type type,
                     uid_t uid, uid_t euid, int force)
{
	write_lock_irq(&filp->f_owner.lock);
	if (force || !filp->f_owner.pid) {
		put_pid(filp->f_owner.pid);
		filp->f_owner.pid = get_pid(pid);
		filp->f_owner.pid_type = type;
		filp->f_owner.uid = uid;
		filp->f_owner.euid = euid;
	}
	write_unlock_irq(&filp->f_owner.lock);
}

int __f_setown(struct file *filp, struct pid *pid, enum pid_type type,
		int force)
{
	int err;
	
	err = security_file_set_fowner(filp);
	if (err)
		return err;

	f_modown(filp, pid, type, current->uid, current->euid, force);
	return 0;
}
EXPORT_SYMBOL(__f_setown);

int f_setown(struct file *filp, unsigned long arg, int force)
{
	enum pid_type type;
	struct pid *pid;
	int who = arg;
	int result;
	type = PIDTYPE_PID;
	if (who < 0) {
		type = PIDTYPE_PGID;
		who = -who;
	}
	rcu_read_lock();
	pid = find_vpid(who);
	result = __f_setown(filp, pid, type, force);
	rcu_read_unlock();
	return result;
}
EXPORT_SYMBOL(f_setown);

void f_delown(struct file *filp)
{
	f_modown(filp, NULL, PIDTYPE_PID, 0, 0, 1);
}

pid_t f_getown(struct file *filp)
{
	pid_t pid;
	read_lock(&filp->f_owner.lock);
	pid = pid_vnr(filp->f_owner.pid);
	if (filp->f_owner.pid_type == PIDTYPE_PGID)
		pid = -pid;
	read_unlock(&filp->f_owner.lock);
	return pid;
}

static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
		struct file *filp)
{
	long err = -EINVAL;

	switch (cmd) {
	case F_DUPFD:
	case F_DUPFD_CLOEXEC:
		get_file(filp);
		err = dupfd(filp, arg, cmd == F_DUPFD_CLOEXEC);
		break;
	case F_GETFD:
		err = get_close_on_exec(fd) ? FD_CLOEXEC : 0;
		break;
	case F_SETFD:
		err = 0;
		set_close_on_exec(fd, arg & FD_CLOEXEC);
		break;
	case F_GETFL:
		err = filp->f_flags;
		break;
	case F_SETFL:
		err = setfl(fd, filp, arg);
		break;
	case F_GETLK:
		err = fcntl_getlk(filp, (struct flock __user *) arg);
		break;
	case F_SETLK:
	case F_SETLKW:
		err = fcntl_setlk(fd, filp, cmd, (struct flock __user *) arg);
		break;
	case F_GETOWN:
		/*
		 * XXX If f_owner is a process group, the
		 * negative return value will get converted
		 * into an error.  Oops.  If we keep the
		 * current syscall conventions, the only way
		 * to fix this will be in libc.
		 */
		err = f_getown(filp);
		force_successful_syscall_return();
		break;
	case F_SETOWN:
		err = f_setown(filp, arg, 1);
		break;
	case F_GETSIG:
		err = filp->f_owner.signum;
		break;
	case F_SETSIG:
		/* arg == 0 restores default behaviour. */
		if (!valid_signal(arg)) {
			break;
		}
		err = 0;
		filp->f_owner.signum = arg;
		break;
	case F_GETLEASE:
		err = fcntl_getlease(filp);
		break;
	case F_SETLEASE:
		err = fcntl_setlease(fd, filp, arg);
		break;
	case F_NOTIFY:
		err = fcntl_dirnotify(fd, filp, arg);
		break;
	default:
		break;
	}
	return err;
}

asmlinkage long sys_fcntl(unsigned int fd, unsigned int cmd, unsigned long arg)
{	
	struct file *filp;
	long err = -EBADF;

	filp = fget(fd);
	if (!filp)
		goto out;

	err = security_file_fcntl(filp, cmd, arg);
	if (err) {
		fput(filp);
		return err;
	}

	err = do_fcntl(fd, cmd, arg, filp);

 	fput(filp);
out:
	return err;
}

#if BITS_PER_LONG == 32
asmlinkage long sys_fcntl64(unsigned int fd, unsigned int cmd, unsigned long arg)
{	
	struct file * filp;
	long err;

	err = -EBADF;
	filp = fget(fd);
	if (!filp)
		goto out;

	err = security_file_fcntl(filp, cmd, arg);
	if (err) {
		fput(filp);
		return err;
	}
	err = -EBADF;
	
	switch (cmd) {
		case F_GETLK64:
			err = fcntl_getlk64(filp, (struct flock64 __user *) arg);
			break;
		case F_SETLK64:
		case F_SETLKW64:
			err = fcntl_setlk64(fd, filp, cmd,
					(struct flock64 __user *) arg);
			break;
		default:
			err = do_fcntl(fd, cmd, arg, filp);
			break;
	}
	fput(filp);
out:
	return err;
}
#endif

/* Table to convert sigio signal codes into poll band bitmaps */

static const long band_table[NSIGPOLL] = {
	POLLIN | POLLRDNORM,			/* POLL_IN */
	POLLOUT | POLLWRNORM | POLLWRBAND,	/* POLL_OUT */
	POLLIN | POLLRDNORM | POLLMSG,		/* POLL_MSG */
	POLLERR,				/* POLL_ERR */
	POLLPRI | POLLRDBAND,			/* POLL_PRI */
	POLLHUP | POLLERR			/* POLL_HUP */
};

static inline int sigio_perm(struct task_struct *p,
                             struct fown_struct *fown, int sig)
{
	return (((fown->euid == 0) ||
		 (fown->euid == p->suid) || (fown->euid == p->uid) ||
		 (fown->uid == p->suid) || (fown->uid == p->uid)) &&
		!security_file_send_sigiotask(p, fown, sig));
}

static void send_sigio_to_task(struct task_struct *p,
			       struct fown_struct *fown, 
			       int fd,
			       int reason)
{
	if (!sigio_perm(p, fown, fown->signum))
		return;

	switch (fown->signum) {
		siginfo_t si;
		default:
			/* Queue a rt signal with the appropriate fd as its
			   value.  We use SI_SIGIO as the source, not 
			   SI_KERNEL, since kernel signals always get 
			   delivered even if we can't queue.  Failure to
			   queue in this case _should_ be reported; we fall
			   back to SIGIO in that case. --sct */
			si.si_signo = fown->signum;
			si.si_errno = 0;
		        si.si_code  = reason;
			/* Make sure we are called with one of the POLL_*
			   reasons, otherwise we could leak kernel stack into
			   userspace.  */
			BUG_ON((reason & __SI_MASK) != __SI_POLL);
			if (reason - POLL_IN >= NSIGPOLL)
				si.si_band  = ~0L;
			else
				si.si_band = band_table[reason - POLL_IN];
			si.si_fd    = fd;
			if (!group_send_sig_info(fown->signum, &si, p))
				break;
		/* fall-through: fall back on the old plain SIGIO signal */
		case 0:
			group_send_sig_info(SIGIO, SEND_SIG_PRIV, p);
	}
}

void send_sigio(struct fown_struct *fown, int fd, int band)
{
	struct task_struct *p;
	enum pid_type type;
	struct pid *pid;
	
	read_lock(&fown->lock);
	type = fown->pid_type;
	pid = fown->pid;
	if (!pid)
		goto out_unlock_fown;
	
	read_lock(&tasklist_lock);
	do_each_pid_task(pid, type, p) {
		send_sigio_to_task(p, fown, fd, band);
	} while_each_pid_task(pid, type, p);
	read_unlock(&tasklist_lock);
 out_unlock_fown:
	read_unlock(&fown->lock);
}

static void send_sigurg_to_task(struct task_struct *p,
                                struct fown_struct *fown)
{
	if (sigio_perm(p, fown, SIGURG))
		group_send_sig_info(SIGURG, SEND_SIG_PRIV, p);
}

int send_sigurg(struct fown_struct *fown)
{
	struct task_struct *p;
	enum pid_type type;
	struct pid *pid;
	int ret = 0;
	
	read_lock(&fown->lock);
	type = fown->pid_type;
	pid = fown->pid;
	if (!pid)
		goto out_unlock_fown;

	ret = 1;
	
	read_lock(&tasklist_lock);
	do_each_pid_task(pid, type, p) {
		send_sigurg_to_task(p, fown);
	} while_each_pid_task(pid, type, p);
	read_unlock(&tasklist_lock);
 out_unlock_fown:
	read_unlock(&fown->lock);
	return ret;
}

static DEFINE_RWLOCK(fasync_lock);
static struct kmem_cache *fasync_cache __read_mostly;

/*
 * fasync_helper() is used by some character device drivers (mainly mice)
 * to set up the fasync queue. It returns negative on error, 0 if it did
 * no changes and positive if it added/deleted the entry.
 */
int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp)
{
	struct fasync_struct *fa, **fp;
	struct fasync_struct *new = NULL;
	int result = 0;

	if (on) {
		new = kmem_cache_alloc(fasync_cache, GFP_KERNEL);
		if (!new)
			return -ENOMEM;
	}
	write_lock_irq(&fasync_lock);
	for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
		if (fa->fa_file == filp) {
			if(on) {
				fa->fa_fd = fd;
				kmem_cache_free(fasync_cache, new);
			} else {
				*fp = fa->fa_next;
				kmem_cache_free(fasync_cache, fa);
				result = 1;
			}
			goto out;
		}
	}

	if (on) {
		new->magic = FASYNC_MAGIC;
		new->fa_file = filp;
		new->fa_fd = fd;
		new->fa_next = *fapp;
		*fapp = new;
		result = 1;
	}
out:
	write_unlock_irq(&fasync_lock);
	return result;
}

EXPORT_SYMBOL(fasync_helper);

void __kill_fasync(struct fasync_struct *fa, int sig, int band)
{
	while (fa) {
		struct fown_struct * fown;
		if (fa->magic != FASYNC_MAGIC) {
			printk(KERN_ERR "kill_fasync: bad magic number in "
			       "fasync_struct!\n");
			return;
		}
		fown = &fa->fa_file->f_owner;
		/* Don't send SIGURG to processes which have not set a
		   queued signum: SIGURG has its own default signalling
		   mechanism. */
		if (!(sig == SIGURG && fown->signum == 0))
			send_sigio(fown, fa->fa_fd, band);
		fa = fa->fa_next;
	}
}

EXPORT_SYMBOL(__kill_fasync);

void kill_fasync(struct fasync_struct **fp, int sig, int band)
{
	/* First a quick test without locking: usually
	 * the list is empty.
	 */
	if (*fp) {
		read_lock(&fasync_lock);
		/* reread *fp after obtaining the lock */
		__kill_fasync(*fp, sig, band);
		read_unlock(&fasync_lock);
	}
}
EXPORT_SYMBOL(kill_fasync);

static int __init fasync_init(void)
{
	fasync_cache = kmem_cache_create("fasync_cache",
		sizeof(struct fasync_struct), 0, SLAB_PANIC, NULL);
	return 0;
}

module_init(fasync_init)
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>
	17	#include <linux/security.h>
	18	#include <linux/ptrace.h>
7ed20e1a	19	#include <linux/signal.h>
ab2af1f5	20	#include <linux/rcupdate.h>
b488893a	21	#include <linux/pid_namespace.h>
1da177e4 LT	22
	23	#include <asm/poll.h>
	24	#include <asm/siginfo.h>
	25	#include <asm/uaccess.h>
	26
fc9b52cd	27	void set_close_on_exec(unsigned int fd, int flag)
1da177e4 LT	28	{
1da177e4 LT	29	struct files_struct *files = current->files;
badf1662	30	struct fdtable *fdt;
1da177e4	31	spin_lock(&files->file_lock);
badf1662	32	fdt = files_fdtable(files);
1da177e4	33	if (flag)
badf1662	34	FD_SET(fd, fdt->close_on_exec);
1da177e4	35	else
badf1662	36	FD_CLR(fd, fdt->close_on_exec);
1da177e4 LT	37	spin_unlock(&files->file_lock);
	38	}
	39
858119e1	40	static int get_close_on_exec(unsigned int fd)
1da177e4 LT	41	{
1da177e4 LT	42	struct files_struct *files = current->files;
badf1662	43	struct fdtable *fdt;
1da177e4	44	int res;
b835996f	45	rcu_read_lock();
badf1662 DS	46	fdt = files_fdtable(files);
badf1662 DS	47	res = FD_ISSET(fd, fdt->close_on_exec);
b835996f	48	rcu_read_unlock();
1da177e4 LT	49	return res;
	50	}
	51
	52	/*
	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.
	56	*/
	57
f8f95702	58	static int locate_fd(unsigned int orig_start, int cloexec)
1da177e4	59	{
f8f95702	60	struct files_struct *files = current->files;
1da177e4 LT	61	unsigned int newfd;
	62	unsigned int start;
	63	int error;
badf1662	64	struct fdtable *fdt;
1da177e4	65
f8f95702 AV	66	spin_lock(&files->file_lock);
f8f95702 AV	67
1da177e4 LT	68	error = -EINVAL;
	69	if (orig_start >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
	70	goto out;
	71
	72	repeat:
ab2af1f5	73	fdt = files_fdtable(files);
1da177e4 LT	74	/*
1da177e4 LT	75	* Someone might have closed fd's in the range
badf1662	76	* orig_start..fdt->next_fd
1da177e4 LT	77	*/
1da177e4 LT	78	start = orig_start;
0c9e63fd ED	79	if (start < files->next_fd)
0c9e63fd ED	80	start = files->next_fd;
1da177e4 LT	81
1da177e4 LT	82	newfd = start;
bbea9f69	83	if (start < fdt->max_fds)
badf1662	84	newfd = find_next_zero_bit(fdt->open_fds->fds_bits,
bbea9f69	85	fdt->max_fds, start);
1da177e4 LT	86
	87	error = -EMFILE;
	88	if (newfd >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
	89	goto out;
	90
	91	error = expand_files(files, newfd);
	92	if (error < 0)
	93	goto out;
	94
	95	/*
	96	* If we needed to expand the fs array we
	97	* might have blocked - try again.
	98	*/
	99	if (error)
	100	goto repeat;
	101
0c9e63fd ED	102	if (start <= files->next_fd)
0c9e63fd ED	103	files->next_fd = newfd + 1;
ab2af1f5	104
f8f95702 AV	105	FD_SET(newfd, fdt->open_fds);
	106	if (cloexec)
	107	FD_SET(newfd, fdt->close_on_exec);
	108	else
	109	FD_CLR(newfd, fdt->close_on_exec);
1da177e4	110	error = newfd;
f8f95702	111
1da177e4	112	out:
f8f95702	113	spin_unlock(&files->file_lock);
1da177e4 LT	114	return error;
	115	}
	116
22d2b35b	117	static int dupfd(struct file *file, unsigned int start, int cloexec)
1da177e4	118	{
f8f95702 AV	119	int fd = locate_fd(start, cloexec);
f8f95702 AV	120	if (fd >= 0)
1da177e4	121	fd_install(fd, file);
f8f95702	122	else
1da177e4	123	fput(file);
1da177e4 LT	124
	125	return fd;
	126	}
	127
	128	asmlinkage long sys_dup2(unsigned int oldfd, unsigned int newfd)
	129	{
	130	int err = -EBADF;
	131	struct file * file, *tofree;
	132	struct files_struct * files = current->files;
badf1662	133	struct fdtable *fdt;
1da177e4 LT	134
	135	spin_lock(&files->file_lock);
	136	if (!(file = fcheck(oldfd)))
	137	goto out_unlock;
	138	err = newfd;
	139	if (newfd == oldfd)
	140	goto out_unlock;
	141	err = -EBADF;
	142	if (newfd >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
	143	goto out_unlock;
	144	get_file(file); /* We are now finished with oldfd */
	145
	146	err = expand_files(files, newfd);
	147	if (err < 0)
	148	goto out_fput;
	149
	150	/* To avoid races with open() and dup(), we will mark the fd as
	151	* in-use in the open-file bitmap throughout the entire dup2()
	152	* process. This is quite safe: do_close() uses the fd array
	153	* entry, not the bitmap, to decide what work needs to be
	154	* done. --sct */
	155	/* Doesn't work. open() might be there first. --AV */
	156
	157	/* Yes. It's a race. In user space. Nothing sane to do */
	158	err = -EBUSY;
badf1662 DS	159	fdt = files_fdtable(files);
	160	tofree = fdt->fd[newfd];
	161	if (!tofree && FD_ISSET(newfd, fdt->open_fds))
1da177e4 LT	162	goto out_fput;
1da177e4 LT	163
ab2af1f5	164	rcu_assign_pointer(fdt->fd[newfd], file);
badf1662 DS	165	FD_SET(newfd, fdt->open_fds);
badf1662 DS	166	FD_CLR(newfd, fdt->close_on_exec);
1da177e4 LT	167	spin_unlock(&files->file_lock);
	168
	169	if (tofree)
	170	filp_close(tofree, files);
	171	err = newfd;
	172	out:
	173	return err;
	174	out_unlock:
	175	spin_unlock(&files->file_lock);
	176	goto out;
	177
	178	out_fput:
	179	spin_unlock(&files->file_lock);
	180	fput(file);
	181	goto out;
	182	}
	183
	184	asmlinkage long sys_dup(unsigned int fildes)
	185	{
	186	int ret = -EBADF;
	187	struct file * file = fget(fildes);
	188
	189	if (file)
22d2b35b	190	ret = dupfd(file, 0, 0);
1da177e4 LT	191	return ret;
	192	}
	193
	194	#define SETFL_MASK (O_APPEND \| O_NONBLOCK \| O_NDELAY \| FASYNC \| O_DIRECT \| O_NOATIME)
	195
	196	static int setfl(int fd, struct file * filp, unsigned long arg)
	197	{
0f7fc9e4	198	struct inode * inode = filp->f_path.dentry->d_inode;
1da177e4 LT	199	int error = 0;
1da177e4 LT	200
7d95c8f2	201	/*
	202	* O_APPEND cannot be cleared if the file is marked as append-only
	203	* and the file is open for write.
	204	*/
	205	if (((arg ^ filp->f_flags) & O_APPEND) && IS_APPEND(inode))
1da177e4 LT	206	return -EPERM;
	207
	208	/* O_NOATIME can only be set by the owner or superuser */
	209	if ((arg & O_NOATIME) && !(filp->f_flags & O_NOATIME))
3bd858ab	210	if (!is_owner_or_cap(inode))
1da177e4 LT	211	return -EPERM;
	212
	213	/* required for strict SunOS emulation */
	214	if (O_NONBLOCK != O_NDELAY)
	215	if (arg & O_NDELAY)
	216	arg \|= O_NONBLOCK;
	217
	218	if (arg & O_DIRECT) {
	219	if (!filp->f_mapping \|\| !filp->f_mapping->a_ops \|\|
	220	!filp->f_mapping->a_ops->direct_IO)
	221	return -EINVAL;
	222	}
	223
	224	if (filp->f_op && filp->f_op->check_flags)
	225	error = filp->f_op->check_flags(arg);
	226	if (error)
	227	return error;
	228
1da177e4 LT	229	if ((arg ^ filp->f_flags) & FASYNC) {
	230	if (filp->f_op && filp->f_op->fasync) {
	231	error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0);
	232	if (error < 0)
	233	goto out;
	234	}
	235	}
	236
	237	filp->f_flags = (arg & SETFL_MASK) \| (filp->f_flags & ~SETFL_MASK);
	238	out:
1da177e4 LT	239	return error;
	240	}
	241
609d7fa9	242	static void f_modown(struct file filp, struct pid pid, enum pid_type type,
1da177e4 LT	243	uid_t uid, uid_t euid, int force)
	244	{
	245	write_lock_irq(&filp->f_owner.lock);
	246	if (force \|\| !filp->f_owner.pid) {
609d7fa9 EB	247	put_pid(filp->f_owner.pid);
	248	filp->f_owner.pid = get_pid(pid);
	249	filp->f_owner.pid_type = type;
1da177e4 LT	250	filp->f_owner.uid = uid;
	251	filp->f_owner.euid = euid;
	252	}
	253	write_unlock_irq(&filp->f_owner.lock);
	254	}
	255
609d7fa9 EB	256	int __f_setown(struct file filp, struct pid pid, enum pid_type type,
609d7fa9 EB	257	int force)
1da177e4 LT	258	{
	259	int err;
	260
	261	err = security_file_set_fowner(filp);
	262	if (err)
	263	return err;
	264
609d7fa9	265	f_modown(filp, pid, type, current->uid, current->euid, force);
1da177e4 LT	266	return 0;
1da177e4 LT	267	}
609d7fa9	268	EXPORT_SYMBOL(__f_setown);
1da177e4	269
609d7fa9 EB	270	int f_setown(struct file *filp, unsigned long arg, int force)
	271	{
	272	enum pid_type type;
	273	struct pid *pid;
	274	int who = arg;
	275	int result;
	276	type = PIDTYPE_PID;
	277	if (who < 0) {
	278	type = PIDTYPE_PGID;
	279	who = -who;
	280	}
	281	rcu_read_lock();
b488893a	282	pid = find_vpid(who);
609d7fa9 EB	283	result = __f_setown(filp, pid, type, force);
	284	rcu_read_unlock();
	285	return result;
	286	}
1da177e4 LT	287	EXPORT_SYMBOL(f_setown);
	288
	289	void f_delown(struct file *filp)
	290	{
609d7fa9 EB	291	f_modown(filp, NULL, PIDTYPE_PID, 0, 0, 1);
	292	}
	293
	294	pid_t f_getown(struct file *filp)
	295	{
	296	pid_t pid;
43fa1adb	297	read_lock(&filp->f_owner.lock);
6c5f3e7b	298	pid = pid_vnr(filp->f_owner.pid);
609d7fa9 EB	299	if (filp->f_owner.pid_type == PIDTYPE_PGID)
609d7fa9 EB	300	pid = -pid;
43fa1adb	301	read_unlock(&filp->f_owner.lock);
609d7fa9	302	return pid;
1da177e4 LT	303	}
	304
	305	static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
	306	struct file *filp)
	307	{
	308	long err = -EINVAL;
	309
	310	switch (cmd) {
	311	case F_DUPFD:
22d2b35b	312	case F_DUPFD_CLOEXEC:
1da177e4	313	get_file(filp);
22d2b35b	314	err = dupfd(filp, arg, cmd == F_DUPFD_CLOEXEC);
1da177e4 LT	315	break;
	316	case F_GETFD:
	317	err = get_close_on_exec(fd) ? FD_CLOEXEC : 0;
	318	break;
	319	case F_SETFD:
	320	err = 0;
	321	set_close_on_exec(fd, arg & FD_CLOEXEC);
	322	break;
	323	case F_GETFL:
	324	err = filp->f_flags;
	325	break;
	326	case F_SETFL:
	327	err = setfl(fd, filp, arg);
	328	break;
	329	case F_GETLK:
	330	err = fcntl_getlk(filp, (struct flock __user *) arg);
	331	break;
	332	case F_SETLK:
	333	case F_SETLKW:
c293621b	334	err = fcntl_setlk(fd, filp, cmd, (struct flock __user *) arg);
1da177e4 LT	335	break;
	336	case F_GETOWN:
	337	/*
	338	* XXX If f_owner is a process group, the
	339	* negative return value will get converted
	340	* into an error. Oops. If we keep the
	341	* current syscall conventions, the only way
	342	* to fix this will be in libc.
	343	*/
609d7fa9	344	err = f_getown(filp);
1da177e4 LT	345	force_successful_syscall_return();
	346	break;
	347	case F_SETOWN:
	348	err = f_setown(filp, arg, 1);
	349	break;
	350	case F_GETSIG:
	351	err = filp->f_owner.signum;
	352	break;
	353	case F_SETSIG:
	354	/* arg == 0 restores default behaviour. */
7ed20e1a	355	if (!valid_signal(arg)) {
1da177e4 LT	356	break;
	357	}
	358	err = 0;
	359	filp->f_owner.signum = arg;
	360	break;
	361	case F_GETLEASE:
	362	err = fcntl_getlease(filp);
	363	break;
	364	case F_SETLEASE:
	365	err = fcntl_setlease(fd, filp, arg);
	366	break;
	367	case F_NOTIFY:
	368	err = fcntl_dirnotify(fd, filp, arg);
	369	break;
	370	default:
	371	break;
	372	}
	373	return err;
	374	}
	375
	376	asmlinkage long sys_fcntl(unsigned int fd, unsigned int cmd, unsigned long arg)
	377	{
	378	struct file *filp;
	379	long err = -EBADF;
	380
	381	filp = fget(fd);
	382	if (!filp)
	383	goto out;
	384
	385	err = security_file_fcntl(filp, cmd, arg);
	386	if (err) {
	387	fput(filp);
	388	return err;
	389	}
	390
	391	err = do_fcntl(fd, cmd, arg, filp);
	392
	393	fput(filp);
	394	out:
	395	return err;
	396	}
	397
	398	#if BITS_PER_LONG == 32
	399	asmlinkage long sys_fcntl64(unsigned int fd, unsigned int cmd, unsigned long arg)
	400	{
	401	struct file * filp;
	402	long err;
	403
	404	err = -EBADF;
	405	filp = fget(fd);
	406	if (!filp)
	407	goto out;
	408
	409	err = security_file_fcntl(filp, cmd, arg);
	410	if (err) {
	411	fput(filp);
	412	return err;
	413	}
	414	err = -EBADF;
	415
	416	switch (cmd) {
	417	case F_GETLK64:
	418	err = fcntl_getlk64(filp, (struct flock64 __user *) arg);
	419	break;
420	case F_SETLK64:
421	case F_SETLKW64:
c293621b PS	422	err = fcntl_setlk64(fd, filp, cmd,
c293621b PS	423	(struct flock64 __user *) arg);
1da177e4 LT	424	break;
	425	default:
	426	err = do_fcntl(fd, cmd, arg, filp);
	427	break;
	428	}
	429	fput(filp);
	430	out:
	431	return err;
	432	}
	433	#endif
	434
	435	/* Table to convert sigio signal codes into poll band bitmaps */
	436
fa3536cc	437	static const long band_table[NSIGPOLL] = {
1da177e4 LT	438	POLLIN \| POLLRDNORM, /* POLL_IN */
	439	POLLOUT \| POLLWRNORM \| POLLWRBAND, /* POLL_OUT */
	440	POLLIN \| POLLRDNORM \| POLLMSG, /* POLL_MSG */
	441	POLLERR, /* POLL_ERR */
	442	POLLPRI \| POLLRDBAND, /* POLL_PRI */
	443	POLLHUP \| POLLERR /* POLL_HUP */
	444	};
	445
	446	static inline int sigio_perm(struct task_struct *p,
	447	struct fown_struct *fown, int sig)
	448	{
	449	return (((fown->euid == 0) \|\|
	450	(fown->euid == p->suid) \|\| (fown->euid == p->uid) \|\|
	451	(fown->uid == p->suid) \|\| (fown->uid == p->uid)) &&
	452	!security_file_send_sigiotask(p, fown, sig));
	453	}
	454
	455	static void send_sigio_to_task(struct task_struct *p,
	456	struct fown_struct *fown,
	457	int fd,
	458	int reason)
	459	{
	460	if (!sigio_perm(p, fown, fown->signum))
	461	return;
	462
	463	switch (fown->signum) {
	464	siginfo_t si;
	465	default:
	466	/* Queue a rt signal with the appropriate fd as its
	467	value. We use SI_SIGIO as the source, not
	468	SI_KERNEL, since kernel signals always get
	469	delivered even if we can't queue. Failure to
	470	queue in this case _should_ be reported; we fall
	471	back to SIGIO in that case. --sct */
	472	si.si_signo = fown->signum;
	473	si.si_errno = 0;
	474	si.si_code = reason;
	475	/* Make sure we are called with one of the POLL_*
	476	reasons, otherwise we could leak kernel stack into
	477	userspace. */
f6298aab	478	BUG_ON((reason & __SI_MASK) != __SI_POLL);
1da177e4 LT	479	if (reason - POLL_IN >= NSIGPOLL)
	480	si.si_band = ~0L;
	481	else
	482	si.si_band = band_table[reason - POLL_IN];
	483	si.si_fd = fd;
850d6fbe	484	if (!group_send_sig_info(fown->signum, &si, p))
1da177e4 LT	485	break;
	486	/* fall-through: fall back on the old plain SIGIO signal */
	487	case 0:
850d6fbe	488	group_send_sig_info(SIGIO, SEND_SIG_PRIV, p);
1da177e4 LT	489	}
	490	}
	491
	492	void send_sigio(struct fown_struct *fown, int fd, int band)
	493	{
	494	struct task_struct *p;
609d7fa9 EB	495	enum pid_type type;
609d7fa9 EB	496	struct pid *pid;
1da177e4 LT	497
1da177e4 LT	498	read_lock(&fown->lock);
609d7fa9	499	type = fown->pid_type;
1da177e4 LT	500	pid = fown->pid;
	501	if (!pid)
	502	goto out_unlock_fown;
	503
	504	read_lock(&tasklist_lock);
609d7fa9 EB	505	do_each_pid_task(pid, type, p) {
	506	send_sigio_to_task(p, fown, fd, band);
	507	} while_each_pid_task(pid, type, p);
1da177e4 LT	508	read_unlock(&tasklist_lock);
	509	out_unlock_fown:
	510	read_unlock(&fown->lock);
	511	}
	512
	513	static void send_sigurg_to_task(struct task_struct *p,
	514	struct fown_struct *fown)
	515	{
	516	if (sigio_perm(p, fown, SIGURG))
850d6fbe	517	group_send_sig_info(SIGURG, SEND_SIG_PRIV, p);
1da177e4 LT	518	}
	519
	520	int send_sigurg(struct fown_struct *fown)
	521	{
	522	struct task_struct *p;
609d7fa9 EB	523	enum pid_type type;
	524	struct pid *pid;
	525	int ret = 0;
1da177e4 LT	526
1da177e4 LT	527	read_lock(&fown->lock);
609d7fa9	528	type = fown->pid_type;
1da177e4 LT	529	pid = fown->pid;
	530	if (!pid)
	531	goto out_unlock_fown;
	532
	533	ret = 1;
	534
	535	read_lock(&tasklist_lock);
609d7fa9 EB	536	do_each_pid_task(pid, type, p) {
	537	send_sigurg_to_task(p, fown);
	538	} while_each_pid_task(pid, type, p);
1da177e4 LT	539	read_unlock(&tasklist_lock);
	540	out_unlock_fown:
	541	read_unlock(&fown->lock);
	542	return ret;
	543	}
	544
	545	static DEFINE_RWLOCK(fasync_lock);
e18b890b	546	static struct kmem_cache *fasync_cache __read_mostly;
1da177e4 LT	547
	548	/*
	549	* fasync_helper() is used by some character device drivers (mainly mice)
	550	* to set up the fasync queue. It returns negative on error, 0 if it did
	551	* no changes and positive if it added/deleted the entry.
	552	*/
	553	int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp)
	554	{
	555	struct fasync_struct fa, *fp;
	556	struct fasync_struct *new = NULL;
	557	int result = 0;
	558
	559	if (on) {
e94b1766	560	new = kmem_cache_alloc(fasync_cache, GFP_KERNEL);
1da177e4 LT	561	if (!new)
	562	return -ENOMEM;
	563	}
	564	write_lock_irq(&fasync_lock);
	565	for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
	566	if (fa->fa_file == filp) {
	567	if(on) {
	568	fa->fa_fd = fd;
	569	kmem_cache_free(fasync_cache, new);
	570	} else {
	571	*fp = fa->fa_next;
	572	kmem_cache_free(fasync_cache, fa);
	573	result = 1;
	574	}
	575	goto out;
	576	}
	577	}
	578
	579	if (on) {
	580	new->magic = FASYNC_MAGIC;
	581	new->fa_file = filp;
	582	new->fa_fd = fd;
	583	new->fa_next = *fapp;
	584	*fapp = new;
	585	result = 1;
	586	}
	587	out:
	588	write_unlock_irq(&fasync_lock);
	589	return result;
	590	}
	591
	592	EXPORT_SYMBOL(fasync_helper);
	593
	594	void __kill_fasync(struct fasync_struct *fa, int sig, int band)
	595	{
	596	while (fa) {
	597	struct fown_struct * fown;
	598	if (fa->magic != FASYNC_MAGIC) {
	599	printk(KERN_ERR "kill_fasync: bad magic number in "
	600	"fasync_struct!\n");
	601	return;
	602	}
	603	fown = &fa->fa_file->f_owner;
	604	/* Don't send SIGURG to processes which have not set a
	605	queued signum: SIGURG has its own default signalling
	606	mechanism. */
	607	if (!(sig == SIGURG && fown->signum == 0))
	608	send_sigio(fown, fa->fa_fd, band);
	609	fa = fa->fa_next;
	610	}
	611	}
	612
	613	EXPORT_SYMBOL(__kill_fasync);
	614
	615	void kill_fasync(struct fasync_struct **fp, int sig, int band)
	616	{
	617	/* First a quick test without locking: usually
	618	* the list is empty.
	619	*/
	620	if (*fp) {
	621	read_lock(&fasync_lock);
	622	/* reread fp after obtaining the lock /
	623	__kill_fasync(*fp, sig, band);
	624	read_unlock(&fasync_lock);
625	}
626	}
627	EXPORT_SYMBOL(kill_fasync);
628
629	static int __init fasync_init(void)
630	{
631	fasync_cache = kmem_cache_create("fasync_cache",
20c2df83	632	sizeof(struct fasync_struct), 0, SLAB_PANIC, NULL);
1da177e4 LT	633	return 0;
	634	}
	635
	636	module_init(fasync_init)