[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/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 <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;
	spin_lock(&files->file_lock);
	if (flag)
		FD_SET(fd, files->close_on_exec);
	else
		FD_CLR(fd, files->close_on_exec);
	spin_unlock(&files->file_lock);
}

static inline int get_close_on_exec(unsigned int fd)
{
	struct files_struct *files = current->files;
	int res;
	spin_lock(&files->file_lock);
	res = FD_ISSET(fd, files->close_on_exec);
	spin_unlock(&files->file_lock);
	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;

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

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

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

	if (start <= files->next_fd)
		files->next_fd = newfd + 1;
	
	error = newfd;
	
out:
	return error;
}

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

	spin_lock(&files->file_lock);
	fd = locate_fd(files, file, start);
	if (fd >= 0) {
		FD_SET(fd, files->open_fds);
		FD_CLR(fd, files->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;

	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;
	tofree = files->fd[newfd];
	if (!tofree && FD_ISSET(newfd, files->open_fds))
		goto out_fput;

	files->fd[newfd] = file;
	FD_SET(newfd, files->open_fds);
	FD_CLR(newfd, files->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 */
	if (!(arg & 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(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(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 (!send_group_sig_info(fown->signum, &si, p))
				break;
		/* fall-through: fall back on the old plain SIGIO signal */
		case 0:
			send_group_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))
		send_group_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>
	12	#include <linux/dnotify.h>
	13	#include <linux/smp_lock.h>
	14	#include <linux/slab.h>
	15	#include <linux/module.h>
	16	#include <linux/security.h>
	17	#include <linux/ptrace.h>
7ed20e1a	18	#include <linux/signal.h>
1da177e4 LT	19
	20	#include <asm/poll.h>
	21	#include <asm/siginfo.h>
	22	#include <asm/uaccess.h>
	23
	24	void fastcall set_close_on_exec(unsigned int fd, int flag)
	25	{
	26	struct files_struct *files = current->files;
	27	spin_lock(&files->file_lock);
	28	if (flag)
	29	FD_SET(fd, files->close_on_exec);
	30	else
	31	FD_CLR(fd, files->close_on_exec);
	32	spin_unlock(&files->file_lock);
	33	}
	34
	35	static inline int get_close_on_exec(unsigned int fd)
	36	{
	37	struct files_struct *files = current->files;
	38	int res;
	39	spin_lock(&files->file_lock);
	40	res = FD_ISSET(fd, files->close_on_exec);
	41	spin_unlock(&files->file_lock);
	42	return res;
	43	}
	44
	45	/*
	46	* locate_fd finds a free file descriptor in the open_fds fdset,
	47	* expanding the fd arrays if necessary. Must be called with the
	48	* file_lock held for write.
	49	*/
	50
	51	static int locate_fd(struct files_struct *files,
	52	struct file *file, unsigned int orig_start)
	53	{
	54	unsigned int newfd;
	55	unsigned int start;
	56	int error;
	57
	58	error = -EINVAL;
	59	if (orig_start >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
	60	goto out;
	61
	62	repeat:
	63	/*
	64	* Someone might have closed fd's in the range
	65	* orig_start..files->next_fd
	66	*/
	67	start = orig_start;
	68	if (start < files->next_fd)
	69	start = files->next_fd;
	70
	71	newfd = start;
	72	if (start < files->max_fdset) {
	73	newfd = find_next_zero_bit(files->open_fds->fds_bits,
	74	files->max_fdset, start);
	75	}
	76
	77	error = -EMFILE;
	78	if (newfd >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
	79	goto out;
	80
	81	error = expand_files(files, newfd);
	82	if (error < 0)
83	goto out;
84
85	/*
86	* If we needed to expand the fs array we
87	* might have blocked - try again.
88	*/
89	if (error)
90	goto repeat;
91
92	if (start <= files->next_fd)
93	files->next_fd = newfd + 1;
94
95	error = newfd;
96
97	out:
98	return error;
99	}
100
101	static int dupfd(struct file *file, unsigned int start)
102	{
103	struct files_struct * files = current->files;
104	int fd;
105
106	spin_lock(&files->file_lock);
107	fd = locate_fd(files, file, start);
108	if (fd >= 0) {
109	FD_SET(fd, files->open_fds);
110	FD_CLR(fd, files->close_on_exec);
111	spin_unlock(&files->file_lock);
112	fd_install(fd, file);
113	} else {
114	spin_unlock(&files->file_lock);
115	fput(file);
116	}
117
118	return fd;
119	}
120
121	asmlinkage long sys_dup2(unsigned int oldfd, unsigned int newfd)
122	{
123	int err = -EBADF;
124	struct file * file, *tofree;
125	struct files_struct * files = current->files;
126
127	spin_lock(&files->file_lock);
128	if (!(file = fcheck(oldfd)))
129	goto out_unlock;
130	err = newfd;
131	if (newfd == oldfd)
132	goto out_unlock;
133	err = -EBADF;
134	if (newfd >= current->signal->rlim[RLIMIT_NOFILE].rlim_cur)
135	goto out_unlock;
136	get_file(file); /* We are now finished with oldfd */
137
138	err = expand_files(files, newfd);
139	if (err < 0)
140	goto out_fput;
141
142	/* To avoid races with open() and dup(), we will mark the fd as
143	* in-use in the open-file bitmap throughout the entire dup2()
144	* process. This is quite safe: do_close() uses the fd array
145	* entry, not the bitmap, to decide what work needs to be
146	* done. --sct */
147	/* Doesn't work. open() might be there first. --AV */
148
149	/* Yes. It's a race. In user space. Nothing sane to do */
150	err = -EBUSY;
151	tofree = files->fd[newfd];
152	if (!tofree && FD_ISSET(newfd, files->open_fds))
153	goto out_fput;
154
155	files->fd[newfd] = file;
156	FD_SET(newfd, files->open_fds);
157	FD_CLR(newfd, files->close_on_exec);
158	spin_unlock(&files->file_lock);
159
160	if (tofree)
161	filp_close(tofree, files);
162	err = newfd;
163	out:
164	return err;
165	out_unlock:
166	spin_unlock(&files->file_lock);
167	goto out;
168
169	out_fput:
170	spin_unlock(&files->file_lock);
171	fput(file);
172	goto out;
173	}
174
175	asmlinkage long sys_dup(unsigned int fildes)
176	{
177	int ret = -EBADF;
178	struct file * file = fget(fildes);
179
180	if (file)
181	ret = dupfd(file, 0);
182	return ret;
183	}
184
185	#define SETFL_MASK (O_APPEND \| O_NONBLOCK \| O_NDELAY \| FASYNC \| O_DIRECT \| O_NOATIME)
186
187	static int setfl(int fd, struct file * filp, unsigned long arg)
188	{
189	struct inode * inode = filp->f_dentry->d_inode;
190	int error = 0;
191
192	/* O_APPEND cannot be cleared if the file is marked as append-only */
193	if (!(arg & O_APPEND) && IS_APPEND(inode))
194	return -EPERM;
195
196	/* O_NOATIME can only be set by the owner or superuser */
197	if ((arg & O_NOATIME) && !(filp->f_flags & O_NOATIME))
198	if (current->fsuid != inode->i_uid && !capable(CAP_FOWNER))
199	return -EPERM;
200
201	/* required for strict SunOS emulation */
202	if (O_NONBLOCK != O_NDELAY)
203	if (arg & O_NDELAY)
204	arg \|= O_NONBLOCK;
205
206	if (arg & O_DIRECT) {
207	if (!filp->f_mapping \|\| !filp->f_mapping->a_ops \|\|
208	!filp->f_mapping->a_ops->direct_IO)
209	return -EINVAL;
210	}
211
212	if (filp->f_op && filp->f_op->check_flags)
213	error = filp->f_op->check_flags(arg);
214	if (error)
215	return error;
216
217	lock_kernel();
218	if ((arg ^ filp->f_flags) & FASYNC) {
219	if (filp->f_op && filp->f_op->fasync) {
220	error = filp->f_op->fasync(fd, filp, (arg & FASYNC) != 0);
221	if (error < 0)
222	goto out;
223	}
224	}
225
226	filp->f_flags = (arg & SETFL_MASK) \| (filp->f_flags & ~SETFL_MASK);
227	out:
228	unlock_kernel();
229	return error;
230	}
231
232	static void f_modown(struct file *filp, unsigned long pid,
233	uid_t uid, uid_t euid, int force)
234	{
235	write_lock_irq(&filp->f_owner.lock);
236	if (force \|\| !filp->f_owner.pid) {
237	filp->f_owner.pid = pid;
238	filp->f_owner.uid = uid;
239	filp->f_owner.euid = euid;
240	}
241	write_unlock_irq(&filp->f_owner.lock);
242	}
243
244	int f_setown(struct file *filp, unsigned long arg, int force)
245	{
246	int err;
247
248	err = security_file_set_fowner(filp);
249	if (err)
250	return err;
251
252	f_modown(filp, arg, current->uid, current->euid, force);
253	return 0;
254	}
255
256	EXPORT_SYMBOL(f_setown);
257
258	void f_delown(struct file *filp)
259	{
260	f_modown(filp, 0, 0, 0, 1);
261	}
262
263	static long do_fcntl(int fd, unsigned int cmd, unsigned long arg,
264	struct file *filp)
265	{
266	long err = -EINVAL;
267
268	switch (cmd) {
269	case F_DUPFD:
270	get_file(filp);
271	err = dupfd(filp, arg);
272	break;
273	case F_GETFD:
274	err = get_close_on_exec(fd) ? FD_CLOEXEC : 0;
275	break;
276	case F_SETFD:
277	err = 0;
278	set_close_on_exec(fd, arg & FD_CLOEXEC);
279	break;
280	case F_GETFL:
281	err = filp->f_flags;
282	break;
283	case F_SETFL:
284	err = setfl(fd, filp, arg);
285	break;
286	case F_GETLK:
287	err = fcntl_getlk(filp, (struct flock __user *) arg);
288	break;
289	case F_SETLK:
290	case F_SETLKW:
291	err = fcntl_setlk(filp, cmd, (struct flock __user *) arg);
292	break;
293	case F_GETOWN:
294	/*
295	* XXX If f_owner is a process group, the
296	* negative return value will get converted
297	* into an error. Oops. If we keep the
298	* current syscall conventions, the only way
299	* to fix this will be in libc.
300	*/
301	err = filp->f_owner.pid;
302	force_successful_syscall_return();
303	break;
304	case F_SETOWN:
305	err = f_setown(filp, arg, 1);
306	break;
307	case F_GETSIG:
308	err = filp->f_owner.signum;
309	break;
310	case F_SETSIG:
311	/* arg == 0 restores default behaviour. */
7ed20e1a	312	if (!valid_signal(arg)) {
1da177e4 LT	313	break;
	314	}
	315	err = 0;
	316	filp->f_owner.signum = arg;
	317	break;
	318	case F_GETLEASE:
	319	err = fcntl_getlease(filp);
	320	break;
	321	case F_SETLEASE:
	322	err = fcntl_setlease(fd, filp, arg);
	323	break;
	324	case F_NOTIFY:
	325	err = fcntl_dirnotify(fd, filp, arg);
	326	break;
	327	default:
	328	break;
	329	}
	330	return err;
	331	}
	332
	333	asmlinkage long sys_fcntl(unsigned int fd, unsigned int cmd, unsigned long arg)
	334	{
	335	struct file *filp;
	336	long err = -EBADF;
	337
	338	filp = fget(fd);
	339	if (!filp)
	340	goto out;
	341
	342	err = security_file_fcntl(filp, cmd, arg);
	343	if (err) {
	344	fput(filp);
	345	return err;
	346	}
	347
	348	err = do_fcntl(fd, cmd, arg, filp);
	349
	350	fput(filp);
	351	out:
	352	return err;
	353	}
	354
	355	#if BITS_PER_LONG == 32
	356	asmlinkage long sys_fcntl64(unsigned int fd, unsigned int cmd, unsigned long arg)
	357	{
	358	struct file * filp;
	359	long err;
	360
	361	err = -EBADF;
	362	filp = fget(fd);
	363	if (!filp)
	364	goto out;
	365
	366	err = security_file_fcntl(filp, cmd, arg);
	367	if (err) {
	368	fput(filp);
	369	return err;
	370	}
	371	err = -EBADF;
	372
	373	switch (cmd) {
	374	case F_GETLK64:
	375	err = fcntl_getlk64(filp, (struct flock64 __user *) arg);
	376	break;
377	case F_SETLK64:
378	case F_SETLKW64:
379	err = fcntl_setlk64(filp, cmd, (struct flock64 __user *) arg);
380	break;
381	default:
382	err = do_fcntl(fd, cmd, arg, filp);
383	break;
384	}
385	fput(filp);
386	out:
387	return err;
388	}
389	#endif
390
391	/* Table to convert sigio signal codes into poll band bitmaps */
392
393	static long band_table[NSIGPOLL] = {
394	POLLIN \| POLLRDNORM, /* POLL_IN */
395	POLLOUT \| POLLWRNORM \| POLLWRBAND, /* POLL_OUT */
396	POLLIN \| POLLRDNORM \| POLLMSG, /* POLL_MSG */
397	POLLERR, /* POLL_ERR */
398	POLLPRI \| POLLRDBAND, /* POLL_PRI */
399	POLLHUP \| POLLERR /* POLL_HUP */
400	};
401
402	static inline int sigio_perm(struct task_struct *p,
403	struct fown_struct *fown, int sig)
404	{
405	return (((fown->euid == 0) \|\|
406	(fown->euid == p->suid) \|\| (fown->euid == p->uid) \|\|
407	(fown->uid == p->suid) \|\| (fown->uid == p->uid)) &&
408	!security_file_send_sigiotask(p, fown, sig));
409	}
410
411	static void send_sigio_to_task(struct task_struct *p,
412	struct fown_struct *fown,
413	int fd,
414	int reason)
415	{
416	if (!sigio_perm(p, fown, fown->signum))
417	return;
418
419	switch (fown->signum) {
420	siginfo_t si;
421	default:
422	/* Queue a rt signal with the appropriate fd as its
423	value. We use SI_SIGIO as the source, not
424	SI_KERNEL, since kernel signals always get
425	delivered even if we can't queue. Failure to
426	queue in this case _should_ be reported; we fall
427	back to SIGIO in that case. --sct */
428	si.si_signo = fown->signum;
429	si.si_errno = 0;
430	si.si_code = reason;
431	/* Make sure we are called with one of the POLL_*
432	reasons, otherwise we could leak kernel stack into
433	userspace. */
434	if ((reason & __SI_MASK) != __SI_POLL)
435	BUG();
436	if (reason - POLL_IN >= NSIGPOLL)
437	si.si_band = ~0L;
438	else
439	si.si_band = band_table[reason - POLL_IN];
440	si.si_fd = fd;
fc9c9ab2	441	if (!send_group_sig_info(fown->signum, &si, p))
1da177e4 LT	442	break;
	443	/* fall-through: fall back on the old plain SIGIO signal */
	444	case 0:
	445	send_group_sig_info(SIGIO, SEND_SIG_PRIV, p);
	446	}
	447	}
	448
	449	void send_sigio(struct fown_struct *fown, int fd, int band)
	450	{
	451	struct task_struct *p;
	452	int pid;
	453
	454	read_lock(&fown->lock);
	455	pid = fown->pid;
	456	if (!pid)
	457	goto out_unlock_fown;
	458
	459	read_lock(&tasklist_lock);
	460	if (pid > 0) {
	461	p = find_task_by_pid(pid);
	462	if (p) {
	463	send_sigio_to_task(p, fown, fd, band);
	464	}
	465	} else {
	466	do_each_task_pid(-pid, PIDTYPE_PGID, p) {
	467	send_sigio_to_task(p, fown, fd, band);
	468	} while_each_task_pid(-pid, PIDTYPE_PGID, p);
	469	}
	470	read_unlock(&tasklist_lock);
	471	out_unlock_fown:
	472	read_unlock(&fown->lock);
	473	}
	474
	475	static void send_sigurg_to_task(struct task_struct *p,
	476	struct fown_struct *fown)
	477	{
	478	if (sigio_perm(p, fown, SIGURG))
	479	send_group_sig_info(SIGURG, SEND_SIG_PRIV, p);
	480	}
	481
	482	int send_sigurg(struct fown_struct *fown)
	483	{
	484	struct task_struct *p;
	485	int pid, ret = 0;
	486
	487	read_lock(&fown->lock);
	488	pid = fown->pid;
	489	if (!pid)
	490	goto out_unlock_fown;
	491
	492	ret = 1;
	493
	494	read_lock(&tasklist_lock);
	495	if (pid > 0) {
	496	p = find_task_by_pid(pid);
	497	if (p) {
	498	send_sigurg_to_task(p, fown);
	499	}
	500	} else {
	501	do_each_task_pid(-pid, PIDTYPE_PGID, p) {
	502	send_sigurg_to_task(p, fown);
	503	} while_each_task_pid(-pid, PIDTYPE_PGID, p);
	504	}
	505	read_unlock(&tasklist_lock);
506	out_unlock_fown:
507	read_unlock(&fown->lock);
508	return ret;
509	}
510
511	static DEFINE_RWLOCK(fasync_lock);
512	static kmem_cache_t *fasync_cache;
513
514	/*
515	* fasync_helper() is used by some character device drivers (mainly mice)
516	* to set up the fasync queue. It returns negative on error, 0 if it did
517	* no changes and positive if it added/deleted the entry.
518	*/
519	int fasync_helper(int fd, struct file * filp, int on, struct fasync_struct **fapp)
520	{
521	struct fasync_struct fa, *fp;
522	struct fasync_struct *new = NULL;
523	int result = 0;
524
525	if (on) {
526	new = kmem_cache_alloc(fasync_cache, SLAB_KERNEL);
527	if (!new)
528	return -ENOMEM;
529	}
530	write_lock_irq(&fasync_lock);
531	for (fp = fapp; (fa = *fp) != NULL; fp = &fa->fa_next) {
532	if (fa->fa_file == filp) {
533	if(on) {
534	fa->fa_fd = fd;
535	kmem_cache_free(fasync_cache, new);
536	} else {
537	*fp = fa->fa_next;
538	kmem_cache_free(fasync_cache, fa);
539	result = 1;
540	}
541	goto out;
542	}
543	}
544
545	if (on) {
546	new->magic = FASYNC_MAGIC;
547	new->fa_file = filp;
548	new->fa_fd = fd;
549	new->fa_next = *fapp;
550	*fapp = new;
551	result = 1;
552	}
553	out:
554	write_unlock_irq(&fasync_lock);
555	return result;
556	}
557
558	EXPORT_SYMBOL(fasync_helper);
559
560	void __kill_fasync(struct fasync_struct *fa, int sig, int band)
561	{
562	while (fa) {
563	struct fown_struct * fown;
564	if (fa->magic != FASYNC_MAGIC) {
565	printk(KERN_ERR "kill_fasync: bad magic number in "
566	"fasync_struct!\n");
567	return;
568	}
569	fown = &fa->fa_file->f_owner;
570	/* Don't send SIGURG to processes which have not set a
571	queued signum: SIGURG has its own default signalling
572	mechanism. */
573	if (!(sig == SIGURG && fown->signum == 0))
574	send_sigio(fown, fa->fa_fd, band);
575	fa = fa->fa_next;
576	}
577	}
578
579	EXPORT_SYMBOL(__kill_fasync);
580
581	void kill_fasync(struct fasync_struct **fp, int sig, int band)
582	{
583	/* First a quick test without locking: usually
584	* the list is empty.
585	*/
586	if (*fp) {
587	read_lock(&fasync_lock);
588	/* reread fp after obtaining the lock /
589	__kill_fasync(*fp, sig, band);
590	read_unlock(&fasync_lock);
591	}
592	}
593	EXPORT_SYMBOL(kill_fasync);
594
595	static int __init fasync_init(void)
596	{
597	fasync_cache = kmem_cache_create("fasync_cache",
598	sizeof(struct fasync_struct), 0, SLAB_PANIC, NULL, NULL);
599	return 0;
600	}
601
602	module_init(fasync_init)