[mirror_ubuntu-bionic-kernel.git] / fs / utimes.c

#include <linux/file.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/utime.h>
#include <linux/syscalls.h>
#include <linux/uaccess.h>
#include <linux/compat.h>
#include <asm/unistd.h>

#ifdef __ARCH_WANT_SYS_UTIME

/*
 * sys_utime() can be implemented in user-level using sys_utimes().
 * Is this for backwards compatibility?  If so, why not move it
 * into the appropriate arch directory (for those architectures that
 * need it).
 */

/* If times==NULL, set access and modification to current time,
 * must be owner or have write permission.
 * Else, update from *times, must be owner or super user.
 */
SYSCALL_DEFINE2(utime, char __user *, filename, struct utimbuf __user *, times)
{
	struct timespec64 tv[2];

	if (times) {
		if (get_user(tv[0].tv_sec, &times->actime) ||
		    get_user(tv[1].tv_sec, &times->modtime))
			return -EFAULT;
		tv[0].tv_nsec = 0;
		tv[1].tv_nsec = 0;
	}
	return do_utimes(AT_FDCWD, filename, times ? tv : NULL, 0);
}

#endif

static bool nsec_valid(long nsec)
{
	if (nsec == UTIME_OMIT || nsec == UTIME_NOW)
		return true;

	return nsec >= 0 && nsec <= 999999999;
}

static int utimes_common(const struct path *path, struct timespec64 *times)
{
	int error;
	struct iattr newattrs;
	struct inode *inode = path->dentry->d_inode;
	struct inode *delegated_inode = NULL;

	error = mnt_want_write(path->mnt);
	if (error)
		goto out;

	if (times && times[0].tv_nsec == UTIME_NOW &&
		     times[1].tv_nsec == UTIME_NOW)
		times = NULL;

	newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME;
	if (times) {
		if (times[0].tv_nsec == UTIME_OMIT)
			newattrs.ia_valid &= ~ATTR_ATIME;
		else if (times[0].tv_nsec != UTIME_NOW) {
			newattrs.ia_atime.tv_sec = times[0].tv_sec;
			newattrs.ia_atime.tv_nsec = times[0].tv_nsec;
			newattrs.ia_valid |= ATTR_ATIME_SET;
		}

		if (times[1].tv_nsec == UTIME_OMIT)
			newattrs.ia_valid &= ~ATTR_MTIME;
		else if (times[1].tv_nsec != UTIME_NOW) {
			newattrs.ia_mtime.tv_sec = times[1].tv_sec;
			newattrs.ia_mtime.tv_nsec = times[1].tv_nsec;
			newattrs.ia_valid |= ATTR_MTIME_SET;
		}
		/*
		 * Tell setattr_prepare(), that this is an explicit time
		 * update, even if neither ATTR_ATIME_SET nor ATTR_MTIME_SET
		 * were used.
		 */
		newattrs.ia_valid |= ATTR_TIMES_SET;
	} else {
		newattrs.ia_valid |= ATTR_TOUCH;
	}
retry_deleg:
	inode_lock(inode);
	error = notify_change(path->dentry, &newattrs, &delegated_inode);
	inode_unlock(inode);
	if (delegated_inode) {
		error = break_deleg_wait(&delegated_inode);
		if (!error)
			goto retry_deleg;
	}

	mnt_drop_write(path->mnt);
out:
	return error;
}

/*
 * do_utimes - change times on filename or file descriptor
 * @dfd: open file descriptor, -1 or AT_FDCWD
 * @filename: path name or NULL
 * @times: new times or NULL
 * @flags: zero or more flags (only AT_SYMLINK_NOFOLLOW for the moment)
 *
 * If filename is NULL and dfd refers to an open file, then operate on
 * the file.  Otherwise look up filename, possibly using dfd as a
 * starting point.
 *
 * If times==NULL, set access and modification to current time,
 * must be owner or have write permission.
 * Else, update from *times, must be owner or super user.
 */
long do_utimes(int dfd, const char __user *filename, struct timespec64 *times,
	       int flags)
{
	int error = -EINVAL;

	if (times && (!nsec_valid(times[0].tv_nsec) ||
		      !nsec_valid(times[1].tv_nsec))) {
		goto out;
	}

	if (flags & ~AT_SYMLINK_NOFOLLOW)
		goto out;

	if (filename == NULL && dfd != AT_FDCWD) {
		struct fd f;

		if (flags & AT_SYMLINK_NOFOLLOW)
			goto out;

		f = fdget(dfd);
		error = -EBADF;
		if (!f.file)
			goto out;

		error = utimes_common(&f.file->f_path, times);
		fdput(f);
	} else {
		struct path path;
		int lookup_flags = 0;

		if (!(flags & AT_SYMLINK_NOFOLLOW))
			lookup_flags |= LOOKUP_FOLLOW;
retry:
		error = user_path_at(dfd, filename, lookup_flags, &path);
		if (error)
			goto out;

		error = utimes_common(&path, times);
		path_put(&path);
		if (retry_estale(error, lookup_flags)) {
			lookup_flags |= LOOKUP_REVAL;
			goto retry;
		}
	}

out:
	return error;
}

SYSCALL_DEFINE4(utimensat, int, dfd, const char __user *, filename,
		struct timespec __user *, utimes, int, flags)
{
	struct timespec64 tstimes[2];

	if (utimes) {
		if ((get_timespec64(&tstimes[0], &utimes[0]) ||
			get_timespec64(&tstimes[1], &utimes[1])))
			return -EFAULT;

		/* Nothing to do, we must not even check the path.  */
		if (tstimes[0].tv_nsec == UTIME_OMIT &&
		    tstimes[1].tv_nsec == UTIME_OMIT)
			return 0;
	}

	return do_utimes(dfd, filename, utimes ? tstimes : NULL, flags);
}

SYSCALL_DEFINE3(futimesat, int, dfd, const char __user *, filename,
		struct timeval __user *, utimes)
{
	struct timeval times[2];
	struct timespec64 tstimes[2];

	if (utimes) {
		if (copy_from_user(&times, utimes, sizeof(times)))
			return -EFAULT;

		/* This test is needed to catch all invalid values.  If we
		   would test only in do_utimes we would miss those invalid
		   values truncated by the multiplication with 1000.  Note
		   that we also catch UTIME_{NOW,OMIT} here which are only
		   valid for utimensat.  */
		if (times[0].tv_usec >= 1000000 || times[0].tv_usec < 0 ||
		    times[1].tv_usec >= 1000000 || times[1].tv_usec < 0)
			return -EINVAL;

		tstimes[0].tv_sec = times[0].tv_sec;
		tstimes[0].tv_nsec = 1000 * times[0].tv_usec;
		tstimes[1].tv_sec = times[1].tv_sec;
		tstimes[1].tv_nsec = 1000 * times[1].tv_usec;
	}

	return do_utimes(dfd, filename, utimes ? tstimes : NULL, 0);
}

SYSCALL_DEFINE2(utimes, char __user *, filename,
		struct timeval __user *, utimes)
{
	return sys_futimesat(AT_FDCWD, filename, utimes);
}

#ifdef CONFIG_COMPAT
/*
 * Not all architectures have sys_utime, so implement this in terms
 * of sys_utimes.
 */
COMPAT_SYSCALL_DEFINE2(utime, const char __user *, filename,
		       struct compat_utimbuf __user *, t)
{
	struct timespec64 tv[2];

	if (t) {
		if (get_user(tv[0].tv_sec, &t->actime) ||
		    get_user(tv[1].tv_sec, &t->modtime))
			return -EFAULT;
		tv[0].tv_nsec = 0;
		tv[1].tv_nsec = 0;
	}
	return do_utimes(AT_FDCWD, filename, t ? tv : NULL, 0);
}

COMPAT_SYSCALL_DEFINE4(utimensat, unsigned int, dfd, const char __user *, filename, struct compat_timespec __user *, t, int, flags)
{
	struct timespec64 tv[2];

	if  (t) {
		if (compat_get_timespec64(&tv[0], &t[0]) ||
		    compat_get_timespec64(&tv[1], &t[1]))
			return -EFAULT;

		if (tv[0].tv_nsec == UTIME_OMIT && tv[1].tv_nsec == UTIME_OMIT)
			return 0;
	}
	return do_utimes(dfd, filename, t ? tv : NULL, flags);
}

COMPAT_SYSCALL_DEFINE3(futimesat, unsigned int, dfd, const char __user *, filename, struct compat_timeval __user *, t)
{
	struct timespec64 tv[2];

	if (t) {
		if (get_user(tv[0].tv_sec, &t[0].tv_sec) ||
		    get_user(tv[0].tv_nsec, &t[0].tv_usec) ||
		    get_user(tv[1].tv_sec, &t[1].tv_sec) ||
		    get_user(tv[1].tv_nsec, &t[1].tv_usec))
			return -EFAULT;
		if (tv[0].tv_nsec >= 1000000 || tv[0].tv_nsec < 0 ||
		    tv[1].tv_nsec >= 1000000 || tv[1].tv_nsec < 0)
			return -EINVAL;
		tv[0].tv_nsec *= 1000;
		tv[1].tv_nsec *= 1000;
	}
	return do_utimes(dfd, filename, t ? tv : NULL, 0);
}

COMPAT_SYSCALL_DEFINE2(utimes, const char __user *, filename, struct compat_timeval __user *, t)
{
	return compat_sys_futimesat(AT_FDCWD, filename, t);
}
#endif
Commit	Line	Data
1c710c89	1	#include <linux/file.h>
74f9fdfa	2	#include <linux/mount.h>
82b0547c AD	3	#include <linux/namei.h>
82b0547c AD	4	#include <linux/utime.h>
12c2ab5e	5	#include <linux/syscalls.h>
7c0f6ba6	6	#include <linux/uaccess.h>
1a060ba3	7	#include <linux/compat.h>
82b0547c AD	8	#include <asm/unistd.h>
	9
	10	#ifdef __ARCH_WANT_SYS_UTIME
	11
	12	/*
	13	* sys_utime() can be implemented in user-level using sys_utimes().
	14	* Is this for backwards compatibility? If so, why not move it
	15	* into the appropriate arch directory (for those architectures that
	16	* need it).
	17	*/
	18
	19	/* If times==NULL, set access and modification to current time,
	20	* must be owner or have write permission.
	21	* Else, update from *times, must be owner or super user.
	22	*/
003d7ab4	23	SYSCALL_DEFINE2(utime, char __user , filename, struct utimbuf __user , times)
82b0547c	24	{
aaed2dd8	25	struct timespec64 tv[2];
82b0547c	26
82b0547c	27	if (times) {
1c710c89 UD	28	if (get_user(tv[0].tv_sec, &times->actime) \|\|
	29	get_user(tv[1].tv_sec, &times->modtime))
	30	return -EFAULT;
	31	tv[0].tv_nsec = 0;
	32	tv[1].tv_nsec = 0;
82b0547c	33	}
1c710c89	34	return do_utimes(AT_FDCWD, filename, times ? tv : NULL, 0);
82b0547c AD	35	}
	36
	37	#endif
	38
043f46f6 MS	39	static bool nsec_valid(long nsec)
043f46f6 MS	40	{
4cca9226	41	if (nsec == UTIME_OMIT \|\| nsec == UTIME_NOW)
043f46f6 MS	42	return true;
	43
	44	return nsec >= 0 && nsec <= 999999999;
	45	}
	46
aaed2dd8	47	static int utimes_common(const struct path path, struct timespec64 times)
82b0547c AD	48	{
82b0547c AD	49	int error;
82b0547c	50	struct iattr newattrs;
e9b76fed	51	struct inode *inode = path->dentry->d_inode;
27ac0ffe	52	struct inode *delegated_inode = NULL;
82b0547c	53
e9b76fed	54	error = mnt_want_write(path->mnt);
74f9fdfa	55	if (error)
e9b76fed	56	goto out;
82b0547c	57
12fd0d30 MK	58	if (times && times[0].tv_nsec == UTIME_NOW &&
	59	times[1].tv_nsec == UTIME_NOW)
	60	times = NULL;
	61
82b0547c AD	62	newattrs.ia_valid = ATTR_CTIME \| ATTR_MTIME \| ATTR_ATIME;
82b0547c AD	63	if (times) {
1c710c89 UD	64	if (times[0].tv_nsec == UTIME_OMIT)
	65	newattrs.ia_valid &= ~ATTR_ATIME;
	66	else if (times[0].tv_nsec != UTIME_NOW) {
	67	newattrs.ia_atime.tv_sec = times[0].tv_sec;
	68	newattrs.ia_atime.tv_nsec = times[0].tv_nsec;
	69	newattrs.ia_valid \|= ATTR_ATIME_SET;
	70	}
	71
	72	if (times[1].tv_nsec == UTIME_OMIT)
	73	newattrs.ia_valid &= ~ATTR_MTIME;
	74	else if (times[1].tv_nsec != UTIME_NOW) {
	75	newattrs.ia_mtime.tv_sec = times[1].tv_sec;
	76	newattrs.ia_mtime.tv_nsec = times[1].tv_nsec;
	77	newattrs.ia_valid \|= ATTR_MTIME_SET;
	78	}
4cca9226	79	/*
31051c85	80	* Tell setattr_prepare(), that this is an explicit time
9767d749 MS	81	* update, even if neither ATTR_ATIME_SET nor ATTR_MTIME_SET
9767d749 MS	82	* were used.
4cca9226	83	*/
9767d749	84	newattrs.ia_valid \|= ATTR_TIMES_SET;
4cca9226	85	} else {
f2b20f6e	86	newattrs.ia_valid \|= ATTR_TOUCH;
82b0547c	87	}
27ac0ffe	88	retry_deleg:
5955102c	89	inode_lock(inode);
27ac0ffe	90	error = notify_change(path->dentry, &newattrs, &delegated_inode);
5955102c	91	inode_unlock(inode);
27ac0ffe BF	92	if (delegated_inode) {
	93	error = break_deleg_wait(&delegated_inode);
	94	if (!error)
	95	goto retry_deleg;
	96	}
e9b76fed	97
e9b76fed MS	98	mnt_drop_write(path->mnt);
	99	out:
	100	return error;
	101	}
	102
	103	/*
	104	* do_utimes - change times on filename or file descriptor
	105	* @dfd: open file descriptor, -1 or AT_FDCWD
	106	* @filename: path name or NULL
	107	* @times: new times or NULL
	108	* @flags: zero or more flags (only AT_SYMLINK_NOFOLLOW for the moment)
	109	*
	110	* If filename is NULL and dfd refers to an open file, then operate on
	111	* the file. Otherwise look up filename, possibly using dfd as a
	112	* starting point.
	113	*
	114	* If times==NULL, set access and modification to current time,
	115	* must be owner or have write permission.
	116	* Else, update from *times, must be owner or super user.
	117	*/
aaed2dd8	118	long do_utimes(int dfd, const char __user filename, struct timespec64 times,
c7887325	119	int flags)
e9b76fed MS	120	{
	121	int error = -EINVAL;
	122
	123	if (times && (!nsec_valid(times[0].tv_nsec) \|\|
	124	!nsec_valid(times[1].tv_nsec))) {
	125	goto out;
	126	}
	127
	128	if (flags & ~AT_SYMLINK_NOFOLLOW)
	129	goto out;
	130
	131	if (filename == NULL && dfd != AT_FDCWD) {
2903ff01	132	struct fd f;
e9b76fed MS	133
	134	if (flags & AT_SYMLINK_NOFOLLOW)
	135	goto out;
	136
2903ff01	137	f = fdget(dfd);
e9b76fed	138	error = -EBADF;
2903ff01	139	if (!f.file)
e9b76fed MS	140	goto out;
e9b76fed MS	141
2903ff01 AV	142	error = utimes_common(&f.file->f_path, times);
2903ff01 AV	143	fdput(f);
e9b76fed	144	} else {
2d8f3038	145	struct path path;
e9b76fed MS	146	int lookup_flags = 0;
	147
	148	if (!(flags & AT_SYMLINK_NOFOLLOW))
	149	lookup_flags \|= LOOKUP_FOLLOW;
a69201d6	150	retry:
2d8f3038	151	error = user_path_at(dfd, filename, lookup_flags, &path);
e9b76fed MS	152	if (error)
	153	goto out;
	154
2d8f3038 AV	155	error = utimes_common(&path, times);
2d8f3038 AV	156	path_put(&path);
a69201d6 JL	157	if (retry_estale(error, lookup_flags)) {
	158	lookup_flags \|= LOOKUP_REVAL;
	159	goto retry;
	160	}
e9b76fed MS	161	}
e9b76fed MS	162
82b0547c AD	163	out:
	164	return error;
	165	}
	166
c7887325	167	SYSCALL_DEFINE4(utimensat, int, dfd, const char __user *, filename,
6559eed8	168	struct timespec __user *, utimes, int, flags)
1c710c89	169	{
aaed2dd8	170	struct timespec64 tstimes[2];
1c710c89 UD	171
1c710c89 UD	172	if (utimes) {
aaed2dd8 DD	173	if ((get_timespec64(&tstimes[0], &utimes[0]) \|\|
aaed2dd8 DD	174	get_timespec64(&tstimes[1], &utimes[1])))
1c710c89	175	return -EFAULT;
1c710c89 UD	176
	177	/* Nothing to do, we must not even check the path. */
	178	if (tstimes[0].tv_nsec == UTIME_OMIT &&
	179	tstimes[1].tv_nsec == UTIME_OMIT)
	180	return 0;
	181	}
	182
	183	return do_utimes(dfd, filename, utimes ? tstimes : NULL, flags);
	184	}
	185
c7887325	186	SYSCALL_DEFINE3(futimesat, int, dfd, const char __user *, filename,
6559eed8	187	struct timeval __user *, utimes)
82b0547c AD	188	{
82b0547c AD	189	struct timeval times[2];
aaed2dd8	190	struct timespec64 tstimes[2];
1c710c89 UD	191
	192	if (utimes) {
	193	if (copy_from_user(&times, utimes, sizeof(times)))
	194	return -EFAULT;
	195
	196	/* This test is needed to catch all invalid values. If we
	197	would test only in do_utimes we would miss those invalid
	198	values truncated by the multiplication with 1000. Note
	199	that we also catch UTIME_{NOW,OMIT} here which are only
	200	valid for utimensat. */
	201	if (times[0].tv_usec >= 1000000 \|\| times[0].tv_usec < 0 \|\|
	202	times[1].tv_usec >= 1000000 \|\| times[1].tv_usec < 0)
	203	return -EINVAL;
	204
	205	tstimes[0].tv_sec = times[0].tv_sec;
	206	tstimes[0].tv_nsec = 1000 * times[0].tv_usec;
	207	tstimes[1].tv_sec = times[1].tv_sec;
	208	tstimes[1].tv_nsec = 1000 * times[1].tv_usec;
	209	}
82b0547c	210
1c710c89	211	return do_utimes(dfd, filename, utimes ? tstimes : NULL, 0);
82b0547c AD	212	}
82b0547c AD	213
003d7ab4 HC	214	SYSCALL_DEFINE2(utimes, char __user *, filename,
003d7ab4 HC	215	struct timeval __user *, utimes)
82b0547c AD	216	{
	217	return sys_futimesat(AT_FDCWD, filename, utimes);
	218	}
1a060ba3 AV	219
	220	#ifdef CONFIG_COMPAT
	221	/*
	222	* Not all architectures have sys_utime, so implement this in terms
	223	* of sys_utimes.
	224	*/
	225	COMPAT_SYSCALL_DEFINE2(utime, const char __user *, filename,
	226	struct compat_utimbuf __user *, t)
	227	{
aaed2dd8	228	struct timespec64 tv[2];
1a060ba3 AV	229
	230	if (t) {
	231	if (get_user(tv[0].tv_sec, &t->actime) \|\|
	232	get_user(tv[1].tv_sec, &t->modtime))
	233	return -EFAULT;
	234	tv[0].tv_nsec = 0;
	235	tv[1].tv_nsec = 0;
	236	}
	237	return do_utimes(AT_FDCWD, filename, t ? tv : NULL, 0);
	238	}
	239
	240	COMPAT_SYSCALL_DEFINE4(utimensat, unsigned int, dfd, const char __user , filename, struct compat_timespec __user , t, int, flags)
	241	{
aaed2dd8	242	struct timespec64 tv[2];
1a060ba3 AV	243
1a060ba3 AV	244	if (t) {
aaed2dd8 DD	245	if (compat_get_timespec64(&tv[0], &t[0]) \|\|
aaed2dd8 DD	246	compat_get_timespec64(&tv[1], &t[1]))
1a060ba3 AV	247	return -EFAULT;
	248
	249	if (tv[0].tv_nsec == UTIME_OMIT && tv[1].tv_nsec == UTIME_OMIT)
	250	return 0;
	251	}
	252	return do_utimes(dfd, filename, t ? tv : NULL, flags);
	253	}
	254
	255	COMPAT_SYSCALL_DEFINE3(futimesat, unsigned int, dfd, const char __user , filename, struct compat_timeval __user , t)
	256	{
aaed2dd8	257	struct timespec64 tv[2];
1a060ba3 AV	258
	259	if (t) {
	260	if (get_user(tv[0].tv_sec, &t[0].tv_sec) \|\|
	261	get_user(tv[0].tv_nsec, &t[0].tv_usec) \|\|
	262	get_user(tv[1].tv_sec, &t[1].tv_sec) \|\|
	263	get_user(tv[1].tv_nsec, &t[1].tv_usec))
	264	return -EFAULT;
	265	if (tv[0].tv_nsec >= 1000000 \|\| tv[0].tv_nsec < 0 \|\|
	266	tv[1].tv_nsec >= 1000000 \|\| tv[1].tv_nsec < 0)
	267	return -EINVAL;
	268	tv[0].tv_nsec *= 1000;
	269	tv[1].tv_nsec *= 1000;
	270	}
	271	return do_utimes(dfd, filename, t ? tv : NULL, 0);
	272	}
	273
	274	COMPAT_SYSCALL_DEFINE2(utimes, const char __user , filename, struct compat_timeval __user , t)
	275	{
	276	return compat_sys_futimesat(AT_FDCWD, filename, t);
	277	}
	278	#endif