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-rw-r--r--fs/utimes.c294
1 files changed, 294 insertions, 0 deletions
diff --git a/fs/utimes.c b/fs/utimes.c
new file mode 100644
index 000000000..69d4b6ba1
--- /dev/null
+++ b/fs/utimes.c
@@ -0,0 +1,294 @@
+// SPDX-License-Identifier: GPL-2.0
+#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);
+}
+
+static long do_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_DEFINE3(futimesat, int, dfd, const char __user *, filename,
+ struct timeval __user *, utimes)
+{
+ return do_futimesat(dfd, filename, utimes);
+}
+
+SYSCALL_DEFINE2(utimes, char __user *, filename,
+ struct timeval __user *, utimes)
+{
+ return do_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);
+}
+
+static long do_compat_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_DEFINE3(futimesat, unsigned int, dfd,
+ const char __user *, filename,
+ struct compat_timeval __user *, t)
+{
+ return do_compat_futimesat(dfd, filename, t);
+}
+
+COMPAT_SYSCALL_DEFINE2(utimes, const char __user *, filename, struct compat_timeval __user *, t)
+{
+ return do_compat_futimesat(AT_FDCWD, filename, t);
+}
+#endif
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