278 lines
7.1 KiB
C
278 lines
7.1 KiB
C
#include <linux/file.h>
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#include <linux/mount.h>
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#include <linux/namei.h>
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#include <linux/utime.h>
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#include <linux/syscalls.h>
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#include <linux/uaccess.h>
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#include <linux/compat.h>
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#include <asm/unistd.h>
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#ifdef __ARCH_WANT_SYS_UTIME
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/*
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* sys_utime() can be implemented in user-level using sys_utimes().
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* Is this for backwards compatibility? If so, why not move it
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* into the appropriate arch directory (for those architectures that
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* need it).
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*/
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/* If times==NULL, set access and modification to current time,
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* must be owner or have write permission.
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* Else, update from *times, must be owner or super user.
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*/
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SYSCALL_DEFINE2(utime, char __user *, filename, struct utimbuf __user *, times)
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{
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struct timespec tv[2];
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if (times) {
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if (get_user(tv[0].tv_sec, ×->actime) ||
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get_user(tv[1].tv_sec, ×->modtime))
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return -EFAULT;
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tv[0].tv_nsec = 0;
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tv[1].tv_nsec = 0;
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}
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return do_utimes(AT_FDCWD, filename, times ? tv : NULL, 0);
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}
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#endif
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static bool nsec_valid(long nsec)
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{
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if (nsec == UTIME_OMIT || nsec == UTIME_NOW)
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return true;
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return nsec >= 0 && nsec <= 999999999;
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}
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static int utimes_common(const struct path *path, struct timespec *times)
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{
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int error;
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struct iattr newattrs;
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struct inode *inode = path->dentry->d_inode;
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struct inode *delegated_inode = NULL;
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error = mnt_want_write(path->mnt);
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if (error)
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goto out;
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if (times && times[0].tv_nsec == UTIME_NOW &&
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times[1].tv_nsec == UTIME_NOW)
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times = NULL;
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newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME;
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if (times) {
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if (times[0].tv_nsec == UTIME_OMIT)
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newattrs.ia_valid &= ~ATTR_ATIME;
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else if (times[0].tv_nsec != UTIME_NOW) {
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newattrs.ia_atime.tv_sec = times[0].tv_sec;
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newattrs.ia_atime.tv_nsec = times[0].tv_nsec;
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newattrs.ia_valid |= ATTR_ATIME_SET;
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}
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if (times[1].tv_nsec == UTIME_OMIT)
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newattrs.ia_valid &= ~ATTR_MTIME;
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else if (times[1].tv_nsec != UTIME_NOW) {
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newattrs.ia_mtime.tv_sec = times[1].tv_sec;
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newattrs.ia_mtime.tv_nsec = times[1].tv_nsec;
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newattrs.ia_valid |= ATTR_MTIME_SET;
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}
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/*
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* Tell setattr_prepare(), that this is an explicit time
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* update, even if neither ATTR_ATIME_SET nor ATTR_MTIME_SET
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* were used.
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*/
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newattrs.ia_valid |= ATTR_TIMES_SET;
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} else {
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newattrs.ia_valid |= ATTR_TOUCH;
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}
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retry_deleg:
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inode_lock(inode);
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error = notify_change(path->dentry, &newattrs, &delegated_inode);
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inode_unlock(inode);
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if (delegated_inode) {
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error = break_deleg_wait(&delegated_inode);
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if (!error)
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goto retry_deleg;
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}
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mnt_drop_write(path->mnt);
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out:
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return error;
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}
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/*
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* do_utimes - change times on filename or file descriptor
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* @dfd: open file descriptor, -1 or AT_FDCWD
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* @filename: path name or NULL
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* @times: new times or NULL
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* @flags: zero or more flags (only AT_SYMLINK_NOFOLLOW for the moment)
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*
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* If filename is NULL and dfd refers to an open file, then operate on
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* the file. Otherwise look up filename, possibly using dfd as a
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* starting point.
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*
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* If times==NULL, set access and modification to current time,
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* must be owner or have write permission.
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* Else, update from *times, must be owner or super user.
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*/
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long do_utimes(int dfd, const char __user *filename, struct timespec *times,
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int flags)
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{
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int error = -EINVAL;
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if (times && (!nsec_valid(times[0].tv_nsec) ||
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!nsec_valid(times[1].tv_nsec))) {
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goto out;
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}
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if (flags & ~AT_SYMLINK_NOFOLLOW)
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goto out;
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if (filename == NULL && dfd != AT_FDCWD) {
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struct fd f;
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if (flags & AT_SYMLINK_NOFOLLOW)
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goto out;
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f = fdget(dfd);
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error = -EBADF;
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if (!f.file)
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goto out;
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error = utimes_common(&f.file->f_path, times);
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fdput(f);
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} else {
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struct path path;
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int lookup_flags = 0;
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if (!(flags & AT_SYMLINK_NOFOLLOW))
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lookup_flags |= LOOKUP_FOLLOW;
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retry:
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error = user_path_at(dfd, filename, lookup_flags, &path);
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if (error)
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goto out;
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error = utimes_common(&path, times);
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path_put(&path);
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if (retry_estale(error, lookup_flags)) {
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lookup_flags |= LOOKUP_REVAL;
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goto retry;
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}
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}
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out:
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return error;
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}
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SYSCALL_DEFINE4(utimensat, int, dfd, const char __user *, filename,
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struct timespec __user *, utimes, int, flags)
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{
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struct timespec tstimes[2];
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if (utimes) {
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if (copy_from_user(&tstimes, utimes, sizeof(tstimes)))
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return -EFAULT;
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/* Nothing to do, we must not even check the path. */
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if (tstimes[0].tv_nsec == UTIME_OMIT &&
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tstimes[1].tv_nsec == UTIME_OMIT)
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return 0;
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}
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return do_utimes(dfd, filename, utimes ? tstimes : NULL, flags);
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}
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SYSCALL_DEFINE3(futimesat, int, dfd, const char __user *, filename,
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struct timeval __user *, utimes)
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{
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struct timeval times[2];
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struct timespec tstimes[2];
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if (utimes) {
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if (copy_from_user(×, utimes, sizeof(times)))
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return -EFAULT;
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/* This test is needed to catch all invalid values. If we
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would test only in do_utimes we would miss those invalid
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values truncated by the multiplication with 1000. Note
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that we also catch UTIME_{NOW,OMIT} here which are only
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valid for utimensat. */
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if (times[0].tv_usec >= 1000000 || times[0].tv_usec < 0 ||
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times[1].tv_usec >= 1000000 || times[1].tv_usec < 0)
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return -EINVAL;
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tstimes[0].tv_sec = times[0].tv_sec;
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tstimes[0].tv_nsec = 1000 * times[0].tv_usec;
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tstimes[1].tv_sec = times[1].tv_sec;
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tstimes[1].tv_nsec = 1000 * times[1].tv_usec;
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}
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return do_utimes(dfd, filename, utimes ? tstimes : NULL, 0);
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}
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SYSCALL_DEFINE2(utimes, char __user *, filename,
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struct timeval __user *, utimes)
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{
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return sys_futimesat(AT_FDCWD, filename, utimes);
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}
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#ifdef CONFIG_COMPAT
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/*
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* Not all architectures have sys_utime, so implement this in terms
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* of sys_utimes.
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*/
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COMPAT_SYSCALL_DEFINE2(utime, const char __user *, filename,
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struct compat_utimbuf __user *, t)
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{
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struct timespec tv[2];
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if (t) {
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if (get_user(tv[0].tv_sec, &t->actime) ||
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get_user(tv[1].tv_sec, &t->modtime))
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return -EFAULT;
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tv[0].tv_nsec = 0;
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tv[1].tv_nsec = 0;
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}
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return do_utimes(AT_FDCWD, filename, t ? tv : NULL, 0);
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}
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COMPAT_SYSCALL_DEFINE4(utimensat, unsigned int, dfd, const char __user *, filename, struct compat_timespec __user *, t, int, flags)
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{
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struct timespec tv[2];
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if (t) {
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if (compat_get_timespec(&tv[0], &t[0]) ||
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compat_get_timespec(&tv[1], &t[1]))
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return -EFAULT;
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if (tv[0].tv_nsec == UTIME_OMIT && tv[1].tv_nsec == UTIME_OMIT)
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return 0;
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}
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return do_utimes(dfd, filename, t ? tv : NULL, flags);
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}
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COMPAT_SYSCALL_DEFINE3(futimesat, unsigned int, dfd, const char __user *, filename, struct compat_timeval __user *, t)
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{
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struct timespec tv[2];
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if (t) {
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if (get_user(tv[0].tv_sec, &t[0].tv_sec) ||
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get_user(tv[0].tv_nsec, &t[0].tv_usec) ||
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get_user(tv[1].tv_sec, &t[1].tv_sec) ||
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get_user(tv[1].tv_nsec, &t[1].tv_usec))
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return -EFAULT;
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if (tv[0].tv_nsec >= 1000000 || tv[0].tv_nsec < 0 ||
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tv[1].tv_nsec >= 1000000 || tv[1].tv_nsec < 0)
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return -EINVAL;
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tv[0].tv_nsec *= 1000;
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tv[1].tv_nsec *= 1000;
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}
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return do_utimes(dfd, filename, t ? tv : NULL, 0);
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}
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COMPAT_SYSCALL_DEFINE2(utimes, const char __user *, filename, struct compat_timeval __user *, t)
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{
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return compat_sys_futimesat(AT_FDCWD, filename, t);
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}
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#endif
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