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#include <linux/compiler.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/linkage.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/sched.h>
#include <linux/stat.h>
#include <linux/utime.h>
#include <linux/syscalls.h>
#include <asm/uaccess.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.
*/
asmlinkage long sys_utime(char __user *filename, struct utimbuf __user *times)
{
struct timespec tv[2];
if (times) {
if (get_user(tv[0].tv_sec, ×->actime) ||
get_user(tv[1].tv_sec, ×->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;
}
/* 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, char __user *filename, struct timespec *times, int flags)
{
int error;
struct nameidata nd;
struct dentry *dentry;
struct inode *inode;
struct iattr newattrs;
struct file *f = NULL;
struct vfsmount *mnt;
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) {
error = -EINVAL;
if (flags & AT_SYMLINK_NOFOLLOW)
goto out;
error = -EBADF;
f = fget(dfd);
if (!f)
goto out;
dentry = f->f_path.dentry;
mnt = f->f_path.mnt;
} else {
error = __user_walk_fd(dfd, filename, (flags & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW, &nd);
if (error)
goto out;
dentry = nd.path.dentry;
mnt = nd.path.mnt;
}
inode = dentry->d_inode;
error = mnt_want_write(mnt);
if (error)
goto dput_and_out;
if (times && times[0].tv_nsec == UTIME_NOW &&
times[1].tv_nsec == UTIME_NOW)
times = NULL;
/* In most cases, the checks are done in inode_change_ok() */
newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME;
if (times) {
error = -EPERM;
if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
goto mnt_drop_write_and_out;
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;
}
/*
* For the UTIME_OMIT/UTIME_NOW and UTIME_NOW/UTIME_OMIT
* cases, we need to make an extra check that is not done by
* inode_change_ok().
*/
if (((times[0].tv_nsec == UTIME_NOW &&
times[1].tv_nsec == UTIME_OMIT)
||
(times[0].tv_nsec == UTIME_OMIT &&
times[1].tv_nsec == UTIME_NOW))
&& !is_owner_or_cap(inode))
goto mnt_drop_write_and_out;
} else {
/*
* If times is NULL (or both times are UTIME_NOW),
* then we need to check permissions, because
* inode_change_ok() won't do it.
*/
error = -EACCES;
if (IS_IMMUTABLE(inode))
goto mnt_drop_write_and_out;
if (!is_owner_or_cap(inode)) {
error = permission(inode, MAY_WRITE, NULL);
if (error)
goto mnt_drop_write_and_out;
}
}
mutex_lock(&inode->i_mutex);
error = notify_change(dentry, &newattrs);
mutex_unlock(&inode->i_mutex);
mnt_drop_write_and_out:
mnt_drop_write(mnt);
dput_and_out:
if (f)
fput(f);
else
path_put(&nd.path);
out:
return error;
}
asmlinkage long sys_utimensat(int dfd, char __user *filename, struct timespec __user *utimes, int flags)
{
struct timespec tstimes[2];
if (utimes) {
if (copy_from_user(&tstimes, utimes, sizeof(tstimes)))
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);
}
asmlinkage long sys_futimesat(int dfd, char __user *filename, struct timeval __user *utimes)
{
struct timeval times[2];
struct timespec tstimes[2];
if (utimes) {
if (copy_from_user(×, 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);
}
asmlinkage long sys_utimes(char __user *filename, struct timeval __user *utimes)
{
return sys_futimesat(AT_FDCWD, filename, utimes);
}
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