[linux.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/capability.h>
#include <linux/dnotify.h>
#include <linux/smp_lock.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 <asm/poll.h>
#include <asm/siginfo.h>
#include <asm/uaccess.h>

void fastcall 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(struct files_struct *files, 
			    struct file *file, unsigned int orig_start)
{
	unsigned int newfd;
	unsigned int start;
	int error;
	struct fdtable *fdt;

	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 < fdt->next_fd)
		start = fdt->next_fd;

	newfd = start;
	if (start < fdt->max_fdset) {
		newfd = find_next_zero_bit(fdt->open_fds->fds_bits,
			fdt->max_fdset, 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;

	/*
	 * We reacquired files_lock, so we are safe as long as
	 * we reacquire the fdtable pointer and use it while holding
	 * the lock, no one can free it during that time.
	 */
	fdt = files_fdtable(files);
	if (start <= fdt->next_fd)
		fdt->next_fd = newfd + 1;

	error = newfd;
	
out:
	return error;
}

static int dupfd(struct file *file, unsigned int start)
{
	struct files_struct * files = current->files;
	struct fdtable *fdt;
	int fd;

	spin_lock(&files->file_lock);
	fd = locate_fd(files, file, start);
	if (fd >= 0) {
		/* locate_fd() may have expanded fdtable, load the ptr */
		fdt = files_fdtable(files);
		FD_SET(fd, fdt->open_fds);
		FD_CLR(fd, fdt->close_on_exec);
		spin_unlock(&files->file_lock);
		fd_install(fd, file);
	} else {
		spin_unlock(&files->file_lock);
		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);
	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_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 (current->fsuid != inode->i_uid && !capable(CAP_FOWNER))
			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;

	lock_kernel();
	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:
	unlock_kernel();
	return error;
}

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

int f_setown(struct file *filp, unsigned long arg, int force)
{
	int err;
	
	err = security_file_set_fowner(filp);
	if (err)
		return err;

	f_modown(filp, arg, current->uid, current->euid, force);
	return 0;
}

EXPORT_SYMBOL(f_setown);

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

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

	switch (cmd) {
	case F_DUPFD:
		get_file(filp);
		err = dupfd(filp, arg);
		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 = filp->f_owner.pid;
		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 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.  */
			if ((reason & __SI_MASK) != __SI_POLL)
				BUG();
			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;
	int pid;
	
	read_lock(&fown->lock);
	pid = fown->pid;
	if (!pid)
		goto out_unlock_fown;
	
	read_lock(&tasklist_lock);
	if (pid > 0) {
		p = find_task_by_pid(pid);
		if (p) {
			send_sigio_to_task(p, fown, fd, band);
		}
	} else {
		do_each_task_pid(-pid, PIDTYPE_PGID, p) {
			send_sigio_to_task(p, fown, fd, band);
		} while_each_task_pid(-pid, PIDTYPE_PGID, 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;
	int pid, ret = 0;
	
	read_lock(&fown->lock);
	pid = fown->pid;
	if (!pid)
		goto out_unlock_fown;

	ret = 1;
	
	read_lock(&tasklist_lock);
	if (pid > 0) {
		p = find_task_by_pid(pid);
		if (p) {
			send_sigurg_to_task(p, fown);
		}
	} else {
		do_each_task_pid(-pid, PIDTYPE_PGID, p) {
			send_sigurg_to_task(p, fown);
		} while_each_task_pid(-pid, PIDTYPE_PGID, p);
	}
	read_unlock(&tasklist_lock);
 out_unlock_fown:
	read_unlock(&fown->lock);
	return ret;
}

static DEFINE_RWLOCK(fasync_lock);
static kmem_cache_t *fasync_cache;

/*
 * 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, SLAB_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, 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>
16f7e0fe	12	#include <linux/capability.h>
1da177e4 LT	13	#include <linux/dnotify.h>
	14	#include <linux/smp_lock.h>
	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>
1da177e4 LT	21
	22	#include <asm/poll.h>
	23	#include <asm/siginfo.h>
	24	#include <asm/uaccess.h>
	25
	26	void fastcall set_close_on_exec(unsigned int fd, int flag)
	27	{
	28	struct files_struct *files = current->files;
badf1662	29	struct fdtable *fdt;
1da177e4	30	spin_lock(&files->file_lock);
badf1662	31	fdt = files_fdtable(files);
1da177e4	32	if (flag)
badf1662	33	FD_SET(fd, fdt->close_on_exec);
1da177e4	34	else
badf1662	35	FD_CLR(fd, fdt->close_on_exec);
1da177e4 LT	36	spin_unlock(&files->file_lock);
	37	}
	38
858119e1	39	static int get_close_on_exec(unsigned int fd)
1da177e4 LT	40	{
1da177e4 LT	41	struct files_struct *files = current->files;
badf1662	42	struct fdtable *fdt;
1da177e4	43	int res;
b835996f	44	rcu_read_lock();
badf1662 DS	45	fdt = files_fdtable(files);
badf1662 DS	46	res = FD_ISSET(fd, fdt->close_on_exec);
b835996f	47	rcu_read_unlock();
1da177e4 LT	48	return res;
	49	}
	50
	51	/*
	52	* locate_fd finds a free file descriptor in the open_fds fdset,
	53	* expanding the fd arrays if necessary. Must be called with the
	54	* file_lock held for write.
	55	*/
	56
	57	static int locate_fd(struct files_struct *files,
	58	struct file *file, unsigned int orig_start)
	59	{
	60	unsigned int newfd;
	61	unsigned int start;
	62	int error;
badf1662	63	struct fdtable *fdt;
1da177e4 LT	64
	65	error = -EINVAL;
	66	if (orig_start >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
	67	goto out;
	68
	69	repeat:
ab2af1f5	70	fdt = files_fdtable(files);
1da177e4 LT	71	/*
1da177e4 LT	72	* Someone might have closed fd's in the range
badf1662	73	* orig_start..fdt->next_fd
1da177e4 LT	74	*/
1da177e4 LT	75	start = orig_start;
badf1662 DS	76	if (start < fdt->next_fd)
badf1662 DS	77	start = fdt->next_fd;
1da177e4 LT	78
1da177e4 LT	79	newfd = start;
badf1662 DS	80	if (start < fdt->max_fdset) {
	81	newfd = find_next_zero_bit(fdt->open_fds->fds_bits,
	82	fdt->max_fdset, start);
1da177e4 LT	83	}
	84
	85	error = -EMFILE;
	86	if (newfd >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
	87	goto out;
	88
	89	error = expand_files(files, newfd);
	90	if (error < 0)
	91	goto out;
	92
	93	/*
	94	* If we needed to expand the fs array we
	95	* might have blocked - try again.
	96	*/
	97	if (error)
	98	goto repeat;
	99
ab2af1f5 DS	100	/*
	101	* We reacquired files_lock, so we are safe as long as
	102	* we reacquire the fdtable pointer and use it while holding
	103	* the lock, no one can free it during that time.
	104	*/
	105	fdt = files_fdtable(files);
badf1662 DS	106	if (start <= fdt->next_fd)
badf1662 DS	107	fdt->next_fd = newfd + 1;
ab2af1f5	108
1da177e4 LT	109	error = newfd;
	110
	111	out:
	112	return error;
	113	}
	114
	115	static int dupfd(struct file *file, unsigned int start)
	116	{
	117	struct files_struct * files = current->files;
badf1662	118	struct fdtable *fdt;
1da177e4 LT	119	int fd;
	120
	121	spin_lock(&files->file_lock);
	122	fd = locate_fd(files, file, start);
	123	if (fd >= 0) {
badf1662 DS	124	/* locate_fd() may have expanded fdtable, load the ptr */
	125	fdt = files_fdtable(files);
	126	FD_SET(fd, fdt->open_fds);
	127	FD_CLR(fd, fdt->close_on_exec);
1da177e4 LT	128	spin_unlock(&files->file_lock);
	129	fd_install(fd, file);
	130	} else {
	131	spin_unlock(&files->file_lock);
	132	fput(file);
	133	}
	134
	135	return fd;
	136	}
	137
	138	asmlinkage long sys_dup2(unsigned int oldfd, unsigned int newfd)
	139	{
	140	int err = -EBADF;
	141	struct file * file, *tofree;
	142	struct files_struct * files = current->files;
badf1662	143	struct fdtable *fdt;
1da177e4 LT	144
	145	spin_lock(&files->file_lock);
	146	if (!(file = fcheck(oldfd)))
	147	goto out_unlock;
	148	err = newfd;
	149	if (newfd == oldfd)
	150	goto out_unlock;
	151	err = -EBADF;
	152	if (newfd >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
	153	goto out_unlock;
	154	get_file(file); /* We are now finished with oldfd */
	155
	156	err = expand_files(files, newfd);
	157	if (err < 0)
	158	goto out_fput;
	159
	160	/* To avoid races with open() and dup(), we will mark the fd as
	161	* in-use in the open-file bitmap throughout the entire dup2()
	162	* process. This is quite safe: do_close() uses the fd array
	163	* entry, not the bitmap, to decide what work needs to be
	164	* done. --sct */
	165	/* Doesn't work. open() might be there first. --AV */
	166
	167	/* Yes. It's a race. In user space. Nothing sane to do */
	168	err = -EBUSY;
badf1662 DS	169	fdt = files_fdtable(files);
	170	tofree = fdt->fd[newfd];
	171	if (!tofree && FD_ISSET(newfd, fdt->open_fds))
1da177e4 LT	172	goto out_fput;
1da177e4 LT	173
ab2af1f5	174	rcu_assign_pointer(fdt->fd[newfd], file);
badf1662 DS	175	FD_SET(newfd, fdt->open_fds);
badf1662 DS	176	FD_CLR(newfd, fdt->close_on_exec);
1da177e4 LT	177	spin_unlock(&files->file_lock);
	178
	179	if (tofree)
	180	filp_close(tofree, files);
	181	err = newfd;
	182	out:
	183	return err;
	184	out_unlock:
	185	spin_unlock(&files->file_lock);
	186	goto out;
	187
	188	out_fput:
	189	spin_unlock(&files->file_lock);
	190	fput(file);
	191	goto out;
	192	}
	193
	194	asmlinkage long sys_dup(unsigned int fildes)
	195	{
	196	int ret = -EBADF;
	197	struct file * file = fget(fildes);
	198
	199	if (file)
	200	ret = dupfd(file, 0);
	201	return ret;
	202	}
	203
	204	#define SETFL_MASK (O_APPEND \| O_NONBLOCK \| O_NDELAY \| FASYNC \| O_DIRECT \| O_NOATIME)
	205
	206	static int setfl(int fd, struct file * filp, unsigned long arg)
	207	{
	208	struct inode * inode = filp->f_dentry->d_inode;
	209	int error = 0;
	210
7d95c8f2	211	/*
	212	* O_APPEND cannot be cleared if the file is marked as append-only
	213	* and the file is open for write.
	214	*/
	215	if (((arg ^ filp->f_flags) & O_APPEND) && IS_APPEND(inode))
1da177e4 LT	216	return -EPERM;
	217
	218	/* O_NOATIME can only be set by the owner or superuser */
	219	if ((arg & O_NOATIME) && !(filp->f_flags & O_NOATIME))
	220	if (current->fsuid != inode->i_uid && !capable(CAP_FOWNER))
	221	return -EPERM;
	222
	223	/* required for strict SunOS emulation */
	224	if (O_NONBLOCK != O_NDELAY)
	225	if (arg & O_NDELAY)
	226	arg \|= O_NONBLOCK;
	227
	228	if (arg & O_DIRECT) {
	229	if (!filp->f_mapping \|\| !filp->f_mapping->a_ops \|\|
	230	!filp->f_mapping->a_ops->direct_IO)
	231	return -EINVAL;
	232	}
	233
	234	if (filp->f_op && filp->f_op->check_flags)
	235	error = filp->f_op->check_flags(arg);
	236	if (error)
	237	return error;
	238
	239	lock_kernel();
	240	if ((arg ^ filp->f_flags) & FASYNC) {
	241	if (filp->f_op && filp->f_op->fasync) {
	242	error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0);
	243	if (error < 0)
	244	goto out;
	245	}
	246	}
	247
	248	filp->f_flags = (arg & SETFL_MASK) \| (filp->f_flags & ~SETFL_MASK);
	249	out:
	250	unlock_kernel();
	251	return error;
	252	}
	253
	254	static void f_modown(struct file *filp, unsigned long pid,
	255	uid_t uid, uid_t euid, int force)
	256	{
	257	write_lock_irq(&filp->f_owner.lock);
	258	if (force \|\| !filp->f_owner.pid) {
	259	filp->f_owner.pid = pid;
	260	filp->f_owner.uid = uid;
	261	filp->f_owner.euid = euid;
	262	}
	263	write_unlock_irq(&filp->f_owner.lock);
	264	}
	265
	266	int f_setown(struct file *filp, unsigned long arg, int force)
	267	{
	268	int err;
	269
	270	err = security_file_set_fowner(filp);
	271	if (err)
	272	return err;
	273
	274	f_modown(filp, arg, current->uid, current->euid, force);
	275	return 0;
	276	}
	277
	278	EXPORT_SYMBOL(f_setown);
	279
280	void f_delown(struct file *filp)
281	{
282	f_modown(filp, 0, 0, 0, 1);
283	}
284
285	static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
286	struct file *filp)
287	{
288	long err = -EINVAL;
289
290	switch (cmd) {
291	case F_DUPFD:
292	get_file(filp);
293	err = dupfd(filp, arg);
294	break;
295	case F_GETFD:
296	err = get_close_on_exec(fd) ? FD_CLOEXEC : 0;
297	break;
298	case F_SETFD:
299	err = 0;
300	set_close_on_exec(fd, arg & FD_CLOEXEC);
301	break;
302	case F_GETFL:
303	err = filp->f_flags;
304	break;
305	case F_SETFL:
306	err = setfl(fd, filp, arg);
307	break;
308	case F_GETLK:
309	err = fcntl_getlk(filp, (struct flock __user *) arg);
310	break;
311	case F_SETLK:
312	case F_SETLKW:
c293621b	313	err = fcntl_setlk(fd, filp, cmd, (struct flock __user *) arg);
1da177e4 LT	314	break;
	315	case F_GETOWN:
	316	/*
	317	* XXX If f_owner is a process group, the
	318	* negative return value will get converted
	319	* into an error. Oops. If we keep the
	320	* current syscall conventions, the only way
	321	* to fix this will be in libc.
	322	*/
	323	err = filp->f_owner.pid;
	324	force_successful_syscall_return();
	325	break;
	326	case F_SETOWN:
	327	err = f_setown(filp, arg, 1);
	328	break;
	329	case F_GETSIG:
	330	err = filp->f_owner.signum;
	331	break;
	332	case F_SETSIG:
	333	/* arg == 0 restores default behaviour. */
7ed20e1a	334	if (!valid_signal(arg)) {
1da177e4 LT	335	break;
	336	}
	337	err = 0;
	338	filp->f_owner.signum = arg;
	339	break;
	340	case F_GETLEASE:
	341	err = fcntl_getlease(filp);
	342	break;
	343	case F_SETLEASE:
	344	err = fcntl_setlease(fd, filp, arg);
	345	break;
	346	case F_NOTIFY:
	347	err = fcntl_dirnotify(fd, filp, arg);
	348	break;
	349	default:
	350	break;
	351	}
	352	return err;
	353	}
	354
	355	asmlinkage long sys_fcntl(unsigned int fd, unsigned int cmd, unsigned long arg)
	356	{
	357	struct file *filp;
	358	long err = -EBADF;
	359
	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
	370	err = do_fcntl(fd, cmd, arg, filp);
	371
	372	fput(filp);
	373	out:
	374	return err;
	375	}
	376
	377	#if BITS_PER_LONG == 32
	378	asmlinkage long sys_fcntl64(unsigned int fd, unsigned int cmd, unsigned long arg)
	379	{
	380	struct file * filp;
	381	long err;
	382
	383	err = -EBADF;
	384	filp = fget(fd);
	385	if (!filp)
	386	goto out;
	387
	388	err = security_file_fcntl(filp, cmd, arg);
	389	if (err) {
	390	fput(filp);
	391	return err;
	392	}
	393	err = -EBADF;
	394
	395	switch (cmd) {
	396	case F_GETLK64:
	397	err = fcntl_getlk64(filp, (struct flock64 __user *) arg);
	398	break;
399	case F_SETLK64:
400	case F_SETLKW64:
c293621b PS	401	err = fcntl_setlk64(fd, filp, cmd,
c293621b PS	402	(struct flock64 __user *) arg);
1da177e4 LT	403	break;
	404	default:
	405	err = do_fcntl(fd, cmd, arg, filp);
	406	break;
	407	}
	408	fput(filp);
	409	out:
	410	return err;
	411	}
	412	#endif
	413
	414	/* Table to convert sigio signal codes into poll band bitmaps */
	415
	416	static long band_table[NSIGPOLL] = {
	417	POLLIN \| POLLRDNORM, /* POLL_IN */
	418	POLLOUT \| POLLWRNORM \| POLLWRBAND, /* POLL_OUT */
	419	POLLIN \| POLLRDNORM \| POLLMSG, /* POLL_MSG */
	420	POLLERR, /* POLL_ERR */
	421	POLLPRI \| POLLRDBAND, /* POLL_PRI */
	422	POLLHUP \| POLLERR /* POLL_HUP */
	423	};
	424
	425	static inline int sigio_perm(struct task_struct *p,
	426	struct fown_struct *fown, int sig)
	427	{
	428	return (((fown->euid == 0) \|\|
	429	(fown->euid == p->suid) \|\| (fown->euid == p->uid) \|\|
	430	(fown->uid == p->suid) \|\| (fown->uid == p->uid)) &&
	431	!security_file_send_sigiotask(p, fown, sig));
	432	}
	433
	434	static void send_sigio_to_task(struct task_struct *p,
	435	struct fown_struct *fown,
	436	int fd,
	437	int reason)
	438	{
	439	if (!sigio_perm(p, fown, fown->signum))
	440	return;
	441
	442	switch (fown->signum) {
	443	siginfo_t si;
	444	default:
	445	/* Queue a rt signal with the appropriate fd as its
	446	value. We use SI_SIGIO as the source, not
	447	SI_KERNEL, since kernel signals always get
	448	delivered even if we can't queue. Failure to
	449	queue in this case _should_ be reported; we fall
	450	back to SIGIO in that case. --sct */
	451	si.si_signo = fown->signum;
	452	si.si_errno = 0;
	453	si.si_code = reason;
	454	/* Make sure we are called with one of the POLL_*
	455	reasons, otherwise we could leak kernel stack into
	456	userspace. */
	457	if ((reason & __SI_MASK) != __SI_POLL)
	458	BUG();
	459	if (reason - POLL_IN >= NSIGPOLL)
	460	si.si_band = ~0L;
	461	else
	462	si.si_band = band_table[reason - POLL_IN];
	463	si.si_fd = fd;
850d6fbe	464	if (!group_send_sig_info(fown->signum, &si, p))
1da177e4 LT	465	break;
	466	/* fall-through: fall back on the old plain SIGIO signal */
	467	case 0:
850d6fbe	468	group_send_sig_info(SIGIO, SEND_SIG_PRIV, p);
1da177e4 LT	469	}
	470	}
	471
	472	void send_sigio(struct fown_struct *fown, int fd, int band)
	473	{
	474	struct task_struct *p;
	475	int pid;
	476
	477	read_lock(&fown->lock);
	478	pid = fown->pid;
	479	if (!pid)
	480	goto out_unlock_fown;
	481
	482	read_lock(&tasklist_lock);
	483	if (pid > 0) {
	484	p = find_task_by_pid(pid);
	485	if (p) {
	486	send_sigio_to_task(p, fown, fd, band);
	487	}
	488	} else {
	489	do_each_task_pid(-pid, PIDTYPE_PGID, p) {
	490	send_sigio_to_task(p, fown, fd, band);
	491	} while_each_task_pid(-pid, PIDTYPE_PGID, p);
	492	}
	493	read_unlock(&tasklist_lock);
	494	out_unlock_fown:
	495	read_unlock(&fown->lock);
	496	}
	497
	498	static void send_sigurg_to_task(struct task_struct *p,
	499	struct fown_struct *fown)
	500	{
	501	if (sigio_perm(p, fown, SIGURG))
850d6fbe	502	group_send_sig_info(SIGURG, SEND_SIG_PRIV, p);
1da177e4 LT	503	}
	504
	505	int send_sigurg(struct fown_struct *fown)
	506	{
	507	struct task_struct *p;
	508	int pid, ret = 0;
	509
	510	read_lock(&fown->lock);
	511	pid = fown->pid;
	512	if (!pid)
	513	goto out_unlock_fown;
	514
	515	ret = 1;
	516
	517	read_lock(&tasklist_lock);
	518	if (pid > 0) {
	519	p = find_task_by_pid(pid);
	520	if (p) {
	521	send_sigurg_to_task(p, fown);
	522	}
	523	} else {
	524	do_each_task_pid(-pid, PIDTYPE_PGID, p) {
	525	send_sigurg_to_task(p, fown);
	526	} while_each_task_pid(-pid, PIDTYPE_PGID, p);
	527	}
	528	read_unlock(&tasklist_lock);
	529	out_unlock_fown:
	530	read_unlock(&fown->lock);
	531	return ret;
	532	}
	533
	534	static DEFINE_RWLOCK(fasync_lock);
	535	static kmem_cache_t *fasync_cache;
	536
	537	/*
	538	* fasync_helper() is used by some character device drivers (mainly mice)
	539	* to set up the fasync queue. It returns negative on error, 0 if it did
	540	* no changes and positive if it added/deleted the entry.
	541	*/
	542	int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp)
	543	{
	544	struct fasync_struct fa, *fp;
	545	struct fasync_struct *new = NULL;
	546	int result = 0;
	547
	548	if (on) {
	549	new = kmem_cache_alloc(fasync_cache, SLAB_KERNEL);
	550	if (!new)
	551	return -ENOMEM;
	552	}
	553	write_lock_irq(&fasync_lock);
	554	for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
	555	if (fa->fa_file == filp) {
	556	if(on) {
	557	fa->fa_fd = fd;
	558	kmem_cache_free(fasync_cache, new);
	559	} else {
	560	*fp = fa->fa_next;
	561	kmem_cache_free(fasync_cache, fa);
	562	result = 1;
	563	}
	564	goto out;
	565	}
	566	}
567
568	if (on) {
569	new->magic = FASYNC_MAGIC;
570	new->fa_file = filp;
571	new->fa_fd = fd;
572	new->fa_next = *fapp;
573	*fapp = new;
574	result = 1;
575	}
576	out:
577	write_unlock_irq(&fasync_lock);
578	return result;
579	}
580
581	EXPORT_SYMBOL(fasync_helper);
582
583	void __kill_fasync(struct fasync_struct *fa, int sig, int band)
584	{
585	while (fa) {
586	struct fown_struct * fown;
587	if (fa->magic != FASYNC_MAGIC) {
588	printk(KERN_ERR "kill_fasync: bad magic number in "
589	"fasync_struct!\n");
590	return;
591	}
592	fown = &fa->fa_file->f_owner;
593	/* Don't send SIGURG to processes which have not set a
594	queued signum: SIGURG has its own default signalling
595	mechanism. */
596	if (!(sig == SIGURG && fown->signum == 0))
597	send_sigio(fown, fa->fa_fd, band);
598	fa = fa->fa_next;
599	}
600	}
601
602	EXPORT_SYMBOL(__kill_fasync);
603
604	void kill_fasync(struct fasync_struct **fp, int sig, int band)
605	{
606	/* First a quick test without locking: usually
607	* the list is empty.
608	*/
609	if (*fp) {
610	read_lock(&fasync_lock);
611	/* reread fp after obtaining the lock /
612	__kill_fasync(*fp, sig, band);
613	read_unlock(&fasync_lock);
614	}
615	}
616	EXPORT_SYMBOL(kill_fasync);
617
618	static int __init fasync_init(void)
619	{
620	fasync_cache = kmem_cache_create("fasync_cache",
621	sizeof(struct fasync_struct), 0, SLAB_PANIC, NULL, NULL);
622	return 0;
623	}
624
625	module_init(fasync_init)