1 #include <linux/compiler.h>
2 #include <linux/file.h>
4 #include <linux/linkage.h>
5 #include <linux/mount.h>
6 #include <linux/namei.h>
7 #include <linux/sched.h>
8 #include <linux/stat.h>
9 #include <linux/utime.h>
10 #include <linux/syscalls.h>
11 #include <asm/uaccess.h>
12 #include <asm/unistd.h>
14 #ifdef __ARCH_WANT_SYS_UTIME
17 * sys_utime() can be implemented in user-level using sys_utimes().
18 * Is this for backwards compatibility? If so, why not move it
19 * into the appropriate arch directory (for those architectures that
23 /* If times==NULL, set access and modification to current time,
24 * must be owner or have write permission.
25 * Else, update from *times, must be owner or super user.
27 asmlinkage long sys_utime(char __user *filename, struct utimbuf __user *times)
29 struct timespec tv[2];
32 if (get_user(tv[0].tv_sec, ×->actime) ||
33 get_user(tv[1].tv_sec, ×->modtime))
38 return do_utimes(AT_FDCWD, filename, times ? tv : NULL, 0);
43 static bool nsec_valid(long nsec)
45 if (nsec == UTIME_OMIT || nsec == UTIME_NOW)
48 return nsec >= 0 && nsec <= 999999999;
51 static int utimes_common(struct path *path, struct timespec *times)
54 struct iattr newattrs;
55 struct inode *inode = path->dentry->d_inode;
57 error = mnt_want_write(path->mnt);
61 if (times && times[0].tv_nsec == UTIME_NOW &&
62 times[1].tv_nsec == UTIME_NOW)
65 newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME;
68 if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
69 goto mnt_drop_write_and_out;
71 if (times[0].tv_nsec == UTIME_OMIT)
72 newattrs.ia_valid &= ~ATTR_ATIME;
73 else if (times[0].tv_nsec != UTIME_NOW) {
74 newattrs.ia_atime.tv_sec = times[0].tv_sec;
75 newattrs.ia_atime.tv_nsec = times[0].tv_nsec;
76 newattrs.ia_valid |= ATTR_ATIME_SET;
79 if (times[1].tv_nsec == UTIME_OMIT)
80 newattrs.ia_valid &= ~ATTR_MTIME;
81 else if (times[1].tv_nsec != UTIME_NOW) {
82 newattrs.ia_mtime.tv_sec = times[1].tv_sec;
83 newattrs.ia_mtime.tv_nsec = times[1].tv_nsec;
84 newattrs.ia_valid |= ATTR_MTIME_SET;
87 * Tell inode_change_ok(), that this is an explicit time
88 * update, even if neither ATTR_ATIME_SET nor ATTR_MTIME_SET
91 newattrs.ia_valid |= ATTR_TIMES_SET;
94 * If times is NULL (or both times are UTIME_NOW),
95 * then we need to check permissions, because
96 * inode_change_ok() won't do it.
99 if (IS_IMMUTABLE(inode))
100 goto mnt_drop_write_and_out;
102 if (!is_owner_or_cap(inode)) {
103 error = permission(inode, MAY_WRITE, NULL);
105 goto mnt_drop_write_and_out;
108 mutex_lock(&inode->i_mutex);
109 error = notify_change(path->dentry, &newattrs);
110 mutex_unlock(&inode->i_mutex);
112 mnt_drop_write_and_out:
113 mnt_drop_write(path->mnt);
119 * do_utimes - change times on filename or file descriptor
120 * @dfd: open file descriptor, -1 or AT_FDCWD
121 * @filename: path name or NULL
122 * @times: new times or NULL
123 * @flags: zero or more flags (only AT_SYMLINK_NOFOLLOW for the moment)
125 * If filename is NULL and dfd refers to an open file, then operate on
126 * the file. Otherwise look up filename, possibly using dfd as a
129 * If times==NULL, set access and modification to current time,
130 * must be owner or have write permission.
131 * Else, update from *times, must be owner or super user.
133 long do_utimes(int dfd, char __user *filename, struct timespec *times, int flags)
137 if (times && (!nsec_valid(times[0].tv_nsec) ||
138 !nsec_valid(times[1].tv_nsec))) {
142 if (flags & ~AT_SYMLINK_NOFOLLOW)
145 if (filename == NULL && dfd != AT_FDCWD) {
148 if (flags & AT_SYMLINK_NOFOLLOW)
156 error = utimes_common(&file->f_path, times);
160 int lookup_flags = 0;
162 if (!(flags & AT_SYMLINK_NOFOLLOW))
163 lookup_flags |= LOOKUP_FOLLOW;
165 error = __user_walk_fd(dfd, filename, lookup_flags, &nd);
169 error = utimes_common(&nd.path, times);
177 asmlinkage long sys_utimensat(int dfd, char __user *filename, struct timespec __user *utimes, int flags)
179 struct timespec tstimes[2];
182 if (copy_from_user(&tstimes, utimes, sizeof(tstimes)))
185 /* Nothing to do, we must not even check the path. */
186 if (tstimes[0].tv_nsec == UTIME_OMIT &&
187 tstimes[1].tv_nsec == UTIME_OMIT)
191 return do_utimes(dfd, filename, utimes ? tstimes : NULL, flags);
194 asmlinkage long sys_futimesat(int dfd, char __user *filename, struct timeval __user *utimes)
196 struct timeval times[2];
197 struct timespec tstimes[2];
200 if (copy_from_user(×, utimes, sizeof(times)))
203 /* This test is needed to catch all invalid values. If we
204 would test only in do_utimes we would miss those invalid
205 values truncated by the multiplication with 1000. Note
206 that we also catch UTIME_{NOW,OMIT} here which are only
207 valid for utimensat. */
208 if (times[0].tv_usec >= 1000000 || times[0].tv_usec < 0 ||
209 times[1].tv_usec >= 1000000 || times[1].tv_usec < 0)
212 tstimes[0].tv_sec = times[0].tv_sec;
213 tstimes[0].tv_nsec = 1000 * times[0].tv_usec;
214 tstimes[1].tv_sec = times[1].tv_sec;
215 tstimes[1].tv_nsec = 1000 * times[1].tv_usec;
218 return do_utimes(dfd, filename, utimes ? tstimes : NULL, 0);
221 asmlinkage long sys_utimes(char __user *filename, struct timeval __user *utimes)
223 return sys_futimesat(AT_FDCWD, filename, utimes);