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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.
- */
- SYSCALL_DEFINE2(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;
- }
- static int utimes_common(struct path *path, struct timespec *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 inode_change_ok(), 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 {
- /*
- * 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 (!inode_owner_or_capable(inode)) {
- error = inode_permission(inode, MAY_WRITE);
- if (error)
- goto mnt_drop_write_and_out;
- }
- }
- retry_deleg:
- mutex_lock(&inode->i_mutex);
- error = notify_change(path->dentry, &newattrs, &delegated_inode);
- mutex_unlock(&inode->i_mutex);
- if (delegated_inode) {
- error = break_deleg_wait(&delegated_inode);
- if (!error)
- goto retry_deleg;
- }
- mnt_drop_write_and_out:
- 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 timespec *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 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);
- }
- SYSCALL_DEFINE3(futimesat, int, dfd, const 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);
- }
- SYSCALL_DEFINE2(utimes, char __user *, filename,
- struct timeval __user *, utimes)
- {
- return sys_futimesat(AT_FDCWD, filename, utimes);
- }
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