[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;
}

asmlinkage long sys_dup3(unsigned int oldfd, unsigned int newfd, int flags)
{
	int err = -EBADF;
	struct file * file, *tofree;
	struct files_struct * files = current->files;
	struct fdtable *fdt;

	if ((flags & ~O_CLOEXEC) != 0)
		return -EINVAL;

	if (unlikely(oldfd == newfd))
		return -EINVAL;

	spin_lock(&files->file_lock);
	err = expand_files(files, newfd);
	file = fcheck(oldfd);
	if (unlikely(!file))
		goto Ebadf;
	if (unlikely(err < 0)) {
		if (err == -EMFILE)
			goto Ebadf;
		goto out_unlock;
	}
	/*
	 * We need to detect attempts to do dup2() over allocated but still
	 * not finished descriptor.  NB: OpenBSD avoids that at the price of
	 * extra work in their equivalent of fget() - they insert struct
	 * file immediately after grabbing descriptor, mark it larval if
	 * more work (e.g. actual opening) is needed and make sure that
	 * fget() treats larval files as absent.  Potentially interesting,
	 * but while extra work in fget() is trivial, locking implications
	 * and amount of surgery on open()-related paths in VFS are not.
	 * FreeBSD fails with -EBADF in the same situation, NetBSD "solution"
	 * deadlocks in rather amusing ways, AFAICS.  All of that is out of
	 * scope of POSIX or SUS, since neither considers shared descriptor
	 * tables and this condition does not arise without those.
	 */
	err = -EBUSY;
	fdt = files_fdtable(files);
	tofree = fdt->fd[newfd];
	if (!tofree && FD_ISSET(newfd, fdt->open_fds))
		goto out_unlock;
	get_file(file);
	rcu_assign_pointer(fdt->fd[newfd], file);
	FD_SET(newfd, fdt->open_fds);
	if (flags & O_CLOEXEC)
		FD_SET(newfd, fdt->close_on_exec);
	else
		FD_CLR(newfd, fdt->close_on_exec);
	spin_unlock(&files->file_lock);

	if (tofree)
		filp_close(tofree, files);

	return newfd;

Ebadf:
	err = -EBADF;
out_unlock:
	spin_unlock(&files->file_lock);
	return err;
}

asmlinkage long sys_dup2(unsigned int oldfd, unsigned int newfd)
{
	if (unlikely(newfd == oldfd)) { /* corner case */
		struct files_struct *files = current->files;
		rcu_read_lock();
		if (!fcheck_files(files, oldfd))
			oldfd = -EBADF;
		rcu_read_unlock();
		return oldfd;
	}
	return sys_dup3(oldfd, newfd, 0);
}

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

	if (file) {
		ret = get_unused_fd();
		if (ret >= 0)
			fd_install(ret, file);
		else
			fput(file);
	}
	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)
{
	const struct cred *cred = current_cred();
	int err;
	
	err = security_file_set_fowner(filp);
	if (err)
		return err;

	f_modown(filp, pid, type, cred->uid, cred->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:
		if (arg >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
			break;
		err = alloc_fd(arg, cmd == F_DUPFD_CLOEXEC ? O_CLOEXEC : 0);
		if (err >= 0) {
			get_file(filp);
			fd_install(err, filp);
		}
		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->cred->suid) || (fown->euid == p->cred->uid) ||
		 (fown->uid == p->cred->suid) || (fown->uid == p->cred->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
336dd1f7	52	asmlinkage long sys_dup3(unsigned int oldfd, unsigned int newfd, int flags)
1da177e4 LT	53	{
	54	int err = -EBADF;
	55	struct file * file, *tofree;
	56	struct files_struct * files = current->files;
badf1662	57	struct fdtable *fdt;
1da177e4	58
336dd1f7 UD	59	if ((flags & ~O_CLOEXEC) != 0)
	60	return -EINVAL;
	61
6c5d0512 AV	62	if (unlikely(oldfd == newfd))
	63	return -EINVAL;
	64
1da177e4	65	spin_lock(&files->file_lock);
1da177e4	66	err = expand_files(files, newfd);
1b7e190b AV	67	file = fcheck(oldfd);
	68	if (unlikely(!file))
	69	goto Ebadf;
4e1e018e AV	70	if (unlikely(err < 0)) {
4e1e018e AV	71	if (err == -EMFILE)
1b7e190b AV	72	goto Ebadf;
1b7e190b AV	73	goto out_unlock;
4e1e018e	74	}
1b7e190b AV	75	/*
	76	* We need to detect attempts to do dup2() over allocated but still
	77	* not finished descriptor. NB: OpenBSD avoids that at the price of
	78	* extra work in their equivalent of fget() - they insert struct
	79	* file immediately after grabbing descriptor, mark it larval if
	80	* more work (e.g. actual opening) is needed and make sure that
	81	* fget() treats larval files as absent. Potentially interesting,
	82	* but while extra work in fget() is trivial, locking implications
	83	* and amount of surgery on open()-related paths in VFS are not.
	84	* FreeBSD fails with -EBADF in the same situation, NetBSD "solution"
	85	* deadlocks in rather amusing ways, AFAICS. All of that is out of
	86	* scope of POSIX or SUS, since neither considers shared descriptor
	87	* tables and this condition does not arise without those.
	88	*/
1da177e4	89	err = -EBUSY;
badf1662 DS	90	fdt = files_fdtable(files);
	91	tofree = fdt->fd[newfd];
	92	if (!tofree && FD_ISSET(newfd, fdt->open_fds))
1b7e190b AV	93	goto out_unlock;
1b7e190b AV	94	get_file(file);
ab2af1f5	95	rcu_assign_pointer(fdt->fd[newfd], file);
badf1662	96	FD_SET(newfd, fdt->open_fds);
336dd1f7 UD	97	if (flags & O_CLOEXEC)
	98	FD_SET(newfd, fdt->close_on_exec);
	99	else
	100	FD_CLR(newfd, fdt->close_on_exec);
1da177e4 LT	101	spin_unlock(&files->file_lock);
	102
	103	if (tofree)
	104	filp_close(tofree, files);
1da177e4	105
1b7e190b AV	106	return newfd;
	107
	108	Ebadf:
	109	err = -EBADF;
	110	out_unlock:
1da177e4	111	spin_unlock(&files->file_lock);
1b7e190b	112	return err;
1da177e4	113	}
336dd1f7 UD	114
	115	asmlinkage long sys_dup2(unsigned int oldfd, unsigned int newfd)
	116	{
6c5d0512 AV	117	if (unlikely(newfd == oldfd)) { /* corner case */
	118	struct files_struct *files = current->files;
	119	rcu_read_lock();
	120	if (!fcheck_files(files, oldfd))
	121	oldfd = -EBADF;
	122	rcu_read_unlock();
	123	return oldfd;
	124	}
336dd1f7 UD	125	return sys_dup3(oldfd, newfd, 0);
336dd1f7 UD	126	}
1da177e4 LT	127
	128	asmlinkage long sys_dup(unsigned int fildes)
	129	{
	130	int ret = -EBADF;
1027abe8 AV	131	struct file *file = fget(fildes);
	132
	133	if (file) {
	134	ret = get_unused_fd();
	135	if (ret >= 0)
	136	fd_install(ret, file);
	137	else
	138	fput(file);
	139	}
1da177e4 LT	140	return ret;
	141	}
	142
	143	#define SETFL_MASK (O_APPEND \| O_NONBLOCK \| O_NDELAY \| FASYNC \| O_DIRECT \| O_NOATIME)
	144
	145	static int setfl(int fd, struct file * filp, unsigned long arg)
	146	{
0f7fc9e4	147	struct inode * inode = filp->f_path.dentry->d_inode;
1da177e4 LT	148	int error = 0;
1da177e4 LT	149
7d95c8f2	150	/*
	151	* O_APPEND cannot be cleared if the file is marked as append-only
	152	* and the file is open for write.
	153	*/
	154	if (((arg ^ filp->f_flags) & O_APPEND) && IS_APPEND(inode))
1da177e4 LT	155	return -EPERM;
	156
	157	/* O_NOATIME can only be set by the owner or superuser */
	158	if ((arg & O_NOATIME) && !(filp->f_flags & O_NOATIME))
3bd858ab	159	if (!is_owner_or_cap(inode))
1da177e4 LT	160	return -EPERM;
	161
	162	/* required for strict SunOS emulation */
	163	if (O_NONBLOCK != O_NDELAY)
	164	if (arg & O_NDELAY)
	165	arg \|= O_NONBLOCK;
	166
	167	if (arg & O_DIRECT) {
	168	if (!filp->f_mapping \|\| !filp->f_mapping->a_ops \|\|
	169	!filp->f_mapping->a_ops->direct_IO)
	170	return -EINVAL;
	171	}
	172
	173	if (filp->f_op && filp->f_op->check_flags)
	174	error = filp->f_op->check_flags(arg);
	175	if (error)
	176	return error;
	177
1da177e4 LT	178	if ((arg ^ filp->f_flags) & FASYNC) {
	179	if (filp->f_op && filp->f_op->fasync) {
	180	error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0);
	181	if (error < 0)
	182	goto out;
	183	}
	184	}
	185
	186	filp->f_flags = (arg & SETFL_MASK) \| (filp->f_flags & ~SETFL_MASK);
	187	out:
1da177e4 LT	188	return error;
	189	}
	190
609d7fa9	191	static void f_modown(struct file filp, struct pid pid, enum pid_type type,
1da177e4 LT	192	uid_t uid, uid_t euid, int force)
	193	{
	194	write_lock_irq(&filp->f_owner.lock);
	195	if (force \|\| !filp->f_owner.pid) {
609d7fa9 EB	196	put_pid(filp->f_owner.pid);
	197	filp->f_owner.pid = get_pid(pid);
	198	filp->f_owner.pid_type = type;
1da177e4 LT	199	filp->f_owner.uid = uid;
	200	filp->f_owner.euid = euid;
	201	}
	202	write_unlock_irq(&filp->f_owner.lock);
	203	}
	204
609d7fa9 EB	205	int __f_setown(struct file filp, struct pid pid, enum pid_type type,
609d7fa9 EB	206	int force)
1da177e4	207	{
86a264ab	208	const struct cred *cred = current_cred();
1da177e4 LT	209	int err;
	210
	211	err = security_file_set_fowner(filp);
	212	if (err)
	213	return err;
	214
86a264ab	215	f_modown(filp, pid, type, cred->uid, cred->euid, force);
1da177e4 LT	216	return 0;
1da177e4 LT	217	}
609d7fa9	218	EXPORT_SYMBOL(__f_setown);
1da177e4	219
609d7fa9 EB	220	int f_setown(struct file *filp, unsigned long arg, int force)
	221	{
	222	enum pid_type type;
	223	struct pid *pid;
	224	int who = arg;
	225	int result;
	226	type = PIDTYPE_PID;
	227	if (who < 0) {
	228	type = PIDTYPE_PGID;
	229	who = -who;
	230	}
	231	rcu_read_lock();
b488893a	232	pid = find_vpid(who);
609d7fa9 EB	233	result = __f_setown(filp, pid, type, force);
	234	rcu_read_unlock();
	235	return result;
	236	}
1da177e4 LT	237	EXPORT_SYMBOL(f_setown);
	238
	239	void f_delown(struct file *filp)
	240	{
609d7fa9 EB	241	f_modown(filp, NULL, PIDTYPE_PID, 0, 0, 1);
	242	}
	243
	244	pid_t f_getown(struct file *filp)
	245	{
	246	pid_t pid;
43fa1adb	247	read_lock(&filp->f_owner.lock);
6c5f3e7b	248	pid = pid_vnr(filp->f_owner.pid);
609d7fa9 EB	249	if (filp->f_owner.pid_type == PIDTYPE_PGID)
609d7fa9 EB	250	pid = -pid;
43fa1adb	251	read_unlock(&filp->f_owner.lock);
609d7fa9	252	return pid;
1da177e4 LT	253	}
	254
	255	static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
	256	struct file *filp)
	257	{
	258	long err = -EINVAL;
	259
	260	switch (cmd) {
	261	case F_DUPFD:
22d2b35b	262	case F_DUPFD_CLOEXEC:
4e1e018e AV	263	if (arg >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
4e1e018e AV	264	break;
1027abe8 AV	265	err = alloc_fd(arg, cmd == F_DUPFD_CLOEXEC ? O_CLOEXEC : 0);
	266	if (err >= 0) {
	267	get_file(filp);
	268	fd_install(err, filp);
	269	}
1da177e4 LT	270	break;
	271	case F_GETFD:
	272	err = get_close_on_exec(fd) ? FD_CLOEXEC : 0;
	273	break;
	274	case F_SETFD:
	275	err = 0;
	276	set_close_on_exec(fd, arg & FD_CLOEXEC);
	277	break;
	278	case F_GETFL:
	279	err = filp->f_flags;
	280	break;
	281	case F_SETFL:
	282	err = setfl(fd, filp, arg);
	283	break;
	284	case F_GETLK:
	285	err = fcntl_getlk(filp, (struct flock __user *) arg);
	286	break;
	287	case F_SETLK:
	288	case F_SETLKW:
c293621b	289	err = fcntl_setlk(fd, filp, cmd, (struct flock __user *) arg);
1da177e4 LT	290	break;
	291	case F_GETOWN:
	292	/*
	293	* XXX If f_owner is a process group, the
	294	* negative return value will get converted
	295	* into an error. Oops. If we keep the
	296	* current syscall conventions, the only way
	297	* to fix this will be in libc.
	298	*/
609d7fa9	299	err = f_getown(filp);
1da177e4 LT	300	force_successful_syscall_return();
	301	break;
	302	case F_SETOWN:
	303	err = f_setown(filp, arg, 1);
	304	break;
	305	case F_GETSIG:
	306	err = filp->f_owner.signum;
	307	break;
	308	case F_SETSIG:
	309	/* arg == 0 restores default behaviour. */
7ed20e1a	310	if (!valid_signal(arg)) {
1da177e4 LT	311	break;
	312	}
	313	err = 0;
	314	filp->f_owner.signum = arg;
	315	break;
	316	case F_GETLEASE:
	317	err = fcntl_getlease(filp);
	318	break;
	319	case F_SETLEASE:
	320	err = fcntl_setlease(fd, filp, arg);
	321	break;
	322	case F_NOTIFY:
	323	err = fcntl_dirnotify(fd, filp, arg);
	324	break;
	325	default:
	326	break;
	327	}
	328	return err;
	329	}
	330
	331	asmlinkage long sys_fcntl(unsigned int fd, unsigned int cmd, unsigned long arg)
	332	{
	333	struct file *filp;
	334	long err = -EBADF;
	335
	336	filp = fget(fd);
	337	if (!filp)
	338	goto out;
	339
	340	err = security_file_fcntl(filp, cmd, arg);
	341	if (err) {
	342	fput(filp);
	343	return err;
	344	}
	345
	346	err = do_fcntl(fd, cmd, arg, filp);
	347
	348	fput(filp);
	349	out:
	350	return err;
	351	}
	352
	353	#if BITS_PER_LONG == 32
	354	asmlinkage long sys_fcntl64(unsigned int fd, unsigned int cmd, unsigned long arg)
	355	{
	356	struct file * filp;
	357	long err;
	358
	359	err = -EBADF;
	360	filp = fget(fd);
	361	if (!filp)
	362	goto out;
	363
	364	err = security_file_fcntl(filp, cmd, arg);
	365	if (err) {
	366	fput(filp);
	367	return err;
	368	}
	369	err = -EBADF;
	370
	371	switch (cmd) {
	372	case F_GETLK64:
	373	err = fcntl_getlk64(filp, (struct flock64 __user *) arg);
	374	break;
375	case F_SETLK64:
376	case F_SETLKW64:
c293621b PS	377	err = fcntl_setlk64(fd, filp, cmd,
c293621b PS	378	(struct flock64 __user *) arg);
1da177e4 LT	379	break;
	380	default:
	381	err = do_fcntl(fd, cmd, arg, filp);
	382	break;
	383	}
	384	fput(filp);
	385	out:
	386	return err;
	387	}
	388	#endif
	389
	390	/* Table to convert sigio signal codes into poll band bitmaps */
	391
fa3536cc	392	static const long band_table[NSIGPOLL] = {
1da177e4 LT	393	POLLIN \| POLLRDNORM, /* POLL_IN */
	394	POLLOUT \| POLLWRNORM \| POLLWRBAND, /* POLL_OUT */
	395	POLLIN \| POLLRDNORM \| POLLMSG, /* POLL_MSG */
	396	POLLERR, /* POLL_ERR */
	397	POLLPRI \| POLLRDBAND, /* POLL_PRI */
	398	POLLHUP \| POLLERR /* POLL_HUP */
	399	};
	400
	401	static inline int sigio_perm(struct task_struct *p,
	402	struct fown_struct *fown, int sig)
	403	{
	404	return (((fown->euid == 0) \|\|
b6dff3ec DH	405	(fown->euid == p->cred->suid) \|\| (fown->euid == p->cred->uid) \|\|
b6dff3ec DH	406	(fown->uid == p->cred->suid) \|\| (fown->uid == p->cred->uid)) &&
1da177e4 LT	407	!security_file_send_sigiotask(p, fown, sig));
	408	}
	409
	410	static void send_sigio_to_task(struct task_struct *p,
	411	struct fown_struct *fown,
	412	int fd,
	413	int reason)
	414	{
	415	if (!sigio_perm(p, fown, fown->signum))
	416	return;
	417
	418	switch (fown->signum) {
	419	siginfo_t si;
	420	default:
	421	/* Queue a rt signal with the appropriate fd as its
	422	value. We use SI_SIGIO as the source, not
	423	SI_KERNEL, since kernel signals always get
	424	delivered even if we can't queue. Failure to
	425	queue in this case _should_ be reported; we fall
	426	back to SIGIO in that case. --sct */
	427	si.si_signo = fown->signum;
	428	si.si_errno = 0;
	429	si.si_code = reason;
	430	/* Make sure we are called with one of the POLL_*
	431	reasons, otherwise we could leak kernel stack into
	432	userspace. */
f6298aab	433	BUG_ON((reason & __SI_MASK) != __SI_POLL);
1da177e4 LT	434	if (reason - POLL_IN >= NSIGPOLL)
	435	si.si_band = ~0L;
	436	else
	437	si.si_band = band_table[reason - POLL_IN];
	438	si.si_fd = fd;
850d6fbe	439	if (!group_send_sig_info(fown->signum, &si, p))
1da177e4 LT	440	break;
	441	/* fall-through: fall back on the old plain SIGIO signal */
	442	case 0:
850d6fbe	443	group_send_sig_info(SIGIO, SEND_SIG_PRIV, p);
1da177e4 LT	444	}
	445	}
	446
	447	void send_sigio(struct fown_struct *fown, int fd, int band)
	448	{
	449	struct task_struct *p;
609d7fa9 EB	450	enum pid_type type;
609d7fa9 EB	451	struct pid *pid;
1da177e4 LT	452
1da177e4 LT	453	read_lock(&fown->lock);
609d7fa9	454	type = fown->pid_type;
1da177e4 LT	455	pid = fown->pid;
	456	if (!pid)
	457	goto out_unlock_fown;
	458
	459	read_lock(&tasklist_lock);
609d7fa9 EB	460	do_each_pid_task(pid, type, p) {
	461	send_sigio_to_task(p, fown, fd, band);
	462	} while_each_pid_task(pid, type, p);
1da177e4 LT	463	read_unlock(&tasklist_lock);
	464	out_unlock_fown:
	465	read_unlock(&fown->lock);
	466	}
	467
	468	static void send_sigurg_to_task(struct task_struct *p,
	469	struct fown_struct *fown)
	470	{
	471	if (sigio_perm(p, fown, SIGURG))
850d6fbe	472	group_send_sig_info(SIGURG, SEND_SIG_PRIV, p);
1da177e4 LT	473	}
	474
	475	int send_sigurg(struct fown_struct *fown)
	476	{
	477	struct task_struct *p;
609d7fa9 EB	478	enum pid_type type;
	479	struct pid *pid;
	480	int ret = 0;
1da177e4 LT	481
1da177e4 LT	482	read_lock(&fown->lock);
609d7fa9	483	type = fown->pid_type;
1da177e4 LT	484	pid = fown->pid;
	485	if (!pid)
	486	goto out_unlock_fown;
	487
	488	ret = 1;
	489
	490	read_lock(&tasklist_lock);
609d7fa9 EB	491	do_each_pid_task(pid, type, p) {
	492	send_sigurg_to_task(p, fown);
	493	} while_each_pid_task(pid, type, p);
1da177e4 LT	494	read_unlock(&tasklist_lock);
	495	out_unlock_fown:
	496	read_unlock(&fown->lock);
	497	return ret;
	498	}
	499
	500	static DEFINE_RWLOCK(fasync_lock);
e18b890b	501	static struct kmem_cache *fasync_cache __read_mostly;
1da177e4 LT	502
	503	/*
	504	* fasync_helper() is used by some character device drivers (mainly mice)
	505	* to set up the fasync queue. It returns negative on error, 0 if it did
	506	* no changes and positive if it added/deleted the entry.
	507	*/
	508	int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp)
	509	{
	510	struct fasync_struct fa, *fp;
	511	struct fasync_struct *new = NULL;
	512	int result = 0;
	513
	514	if (on) {
e94b1766	515	new = kmem_cache_alloc(fasync_cache, GFP_KERNEL);
1da177e4 LT	516	if (!new)
	517	return -ENOMEM;
	518	}
	519	write_lock_irq(&fasync_lock);
	520	for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
	521	if (fa->fa_file == filp) {
	522	if(on) {
	523	fa->fa_fd = fd;
	524	kmem_cache_free(fasync_cache, new);
	525	} else {
	526	*fp = fa->fa_next;
	527	kmem_cache_free(fasync_cache, fa);
	528	result = 1;
	529	}
	530	goto out;
	531	}
	532	}
	533
	534	if (on) {
	535	new->magic = FASYNC_MAGIC;
	536	new->fa_file = filp;
	537	new->fa_fd = fd;
	538	new->fa_next = *fapp;
	539	*fapp = new;
	540	result = 1;
	541	}
	542	out:
	543	write_unlock_irq(&fasync_lock);
	544	return result;
	545	}
	546
	547	EXPORT_SYMBOL(fasync_helper);
	548
	549	void __kill_fasync(struct fasync_struct *fa, int sig, int band)
	550	{
	551	while (fa) {
	552	struct fown_struct * fown;
	553	if (fa->magic != FASYNC_MAGIC) {
	554	printk(KERN_ERR "kill_fasync: bad magic number in "
	555	"fasync_struct!\n");
	556	return;
	557	}
	558	fown = &fa->fa_file->f_owner;
	559	/* Don't send SIGURG to processes which have not set a
	560	queued signum: SIGURG has its own default signalling
	561	mechanism. */
	562	if (!(sig == SIGURG && fown->signum == 0))
	563	send_sigio(fown, fa->fa_fd, band);
	564	fa = fa->fa_next;
	565	}
	566	}
	567
	568	EXPORT_SYMBOL(__kill_fasync);
	569
	570	void kill_fasync(struct fasync_struct **fp, int sig, int band)
	571	{
	572	/* First a quick test without locking: usually
	573	* the list is empty.
	574	*/
	575	if (*fp) {
	576	read_lock(&fasync_lock);
	577	/* reread fp after obtaining the lock /
	578	__kill_fasync(*fp, sig, band);
	579	read_unlock(&fasync_lock);
580	}
581	}
582	EXPORT_SYMBOL(kill_fasync);
583
584	static int __init fasync_init(void)
585	{
586	fasync_cache = kmem_cache_create("fasync_cache",
20c2df83	587	sizeof(struct fasync_struct), 0, SLAB_PANIC, NULL);
1da177e4 LT	588	return 0;
	589	}
	590
	591	module_init(fasync_init)