]> git.kernelconcepts.de Git - karo-tx-linux.git/blob - fs/utimes.c
Merge branch 'for-linus-bugs' of git://git.kernel.org/pub/scm/linux/kernel/git/sage...
[karo-tx-linux.git] / fs / utimes.c
1 #include <linux/compiler.h>
2 #include <linux/file.h>
3 #include <linux/fs.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>
13
14 #ifdef __ARCH_WANT_SYS_UTIME
15
16 /*
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
20  * need it).
21  */
22
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.
26  */
27 SYSCALL_DEFINE2(utime, char __user *, filename, struct utimbuf __user *, times)
28 {
29         struct timespec tv[2];
30
31         if (times) {
32                 if (get_user(tv[0].tv_sec, &times->actime) ||
33                     get_user(tv[1].tv_sec, &times->modtime))
34                         return -EFAULT;
35                 tv[0].tv_nsec = 0;
36                 tv[1].tv_nsec = 0;
37         }
38         return do_utimes(AT_FDCWD, filename, times ? tv : NULL, 0);
39 }
40
41 #endif
42
43 static bool nsec_valid(long nsec)
44 {
45         if (nsec == UTIME_OMIT || nsec == UTIME_NOW)
46                 return true;
47
48         return nsec >= 0 && nsec <= 999999999;
49 }
50
51 static int utimes_common(struct path *path, struct timespec *times)
52 {
53         int error;
54         struct iattr newattrs;
55         struct inode *inode = path->dentry->d_inode;
56         struct inode *delegated_inode = NULL;
57
58         error = mnt_want_write(path->mnt);
59         if (error)
60                 goto out;
61
62         if (times && times[0].tv_nsec == UTIME_NOW &&
63                      times[1].tv_nsec == UTIME_NOW)
64                 times = NULL;
65
66         newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME;
67         if (times) {
68                 if (times[0].tv_nsec == UTIME_OMIT)
69                         newattrs.ia_valid &= ~ATTR_ATIME;
70                 else if (times[0].tv_nsec != UTIME_NOW) {
71                         newattrs.ia_atime.tv_sec = times[0].tv_sec;
72                         newattrs.ia_atime.tv_nsec = times[0].tv_nsec;
73                         newattrs.ia_valid |= ATTR_ATIME_SET;
74                 }
75
76                 if (times[1].tv_nsec == UTIME_OMIT)
77                         newattrs.ia_valid &= ~ATTR_MTIME;
78                 else if (times[1].tv_nsec != UTIME_NOW) {
79                         newattrs.ia_mtime.tv_sec = times[1].tv_sec;
80                         newattrs.ia_mtime.tv_nsec = times[1].tv_nsec;
81                         newattrs.ia_valid |= ATTR_MTIME_SET;
82                 }
83                 /*
84                  * Tell inode_change_ok(), that this is an explicit time
85                  * update, even if neither ATTR_ATIME_SET nor ATTR_MTIME_SET
86                  * were used.
87                  */
88                 newattrs.ia_valid |= ATTR_TIMES_SET;
89         } else {
90                 /*
91                  * If times is NULL (or both times are UTIME_NOW),
92                  * then we need to check permissions, because
93                  * inode_change_ok() won't do it.
94                  */
95                 error = -EACCES;
96                 if (IS_IMMUTABLE(inode))
97                         goto mnt_drop_write_and_out;
98
99                 if (!inode_owner_or_capable(inode)) {
100                         error = inode_permission(inode, MAY_WRITE);
101                         if (error)
102                                 goto mnt_drop_write_and_out;
103                 }
104         }
105 retry_deleg:
106         mutex_lock(&inode->i_mutex);
107         error = notify_change(path->dentry, &newattrs, &delegated_inode);
108         mutex_unlock(&inode->i_mutex);
109         if (delegated_inode) {
110                 error = break_deleg_wait(&delegated_inode);
111                 if (!error)
112                         goto retry_deleg;
113         }
114
115 mnt_drop_write_and_out:
116         mnt_drop_write(path->mnt);
117 out:
118         return error;
119 }
120
121 /*
122  * do_utimes - change times on filename or file descriptor
123  * @dfd: open file descriptor, -1 or AT_FDCWD
124  * @filename: path name or NULL
125  * @times: new times or NULL
126  * @flags: zero or more flags (only AT_SYMLINK_NOFOLLOW for the moment)
127  *
128  * If filename is NULL and dfd refers to an open file, then operate on
129  * the file.  Otherwise look up filename, possibly using dfd as a
130  * starting point.
131  *
132  * If times==NULL, set access and modification to current time,
133  * must be owner or have write permission.
134  * Else, update from *times, must be owner or super user.
135  */
136 long do_utimes(int dfd, const char __user *filename, struct timespec *times,
137                int flags)
138 {
139         int error = -EINVAL;
140
141         if (times && (!nsec_valid(times[0].tv_nsec) ||
142                       !nsec_valid(times[1].tv_nsec))) {
143                 goto out;
144         }
145
146         if (flags & ~AT_SYMLINK_NOFOLLOW)
147                 goto out;
148
149         if (filename == NULL && dfd != AT_FDCWD) {
150                 struct fd f;
151
152                 if (flags & AT_SYMLINK_NOFOLLOW)
153                         goto out;
154
155                 f = fdget(dfd);
156                 error = -EBADF;
157                 if (!f.file)
158                         goto out;
159
160                 error = utimes_common(&f.file->f_path, times);
161                 fdput(f);
162         } else {
163                 struct path path;
164                 int lookup_flags = 0;
165
166                 if (!(flags & AT_SYMLINK_NOFOLLOW))
167                         lookup_flags |= LOOKUP_FOLLOW;
168 retry:
169                 error = user_path_at(dfd, filename, lookup_flags, &path);
170                 if (error)
171                         goto out;
172
173                 error = utimes_common(&path, times);
174                 path_put(&path);
175                 if (retry_estale(error, lookup_flags)) {
176                         lookup_flags |= LOOKUP_REVAL;
177                         goto retry;
178                 }
179         }
180
181 out:
182         return error;
183 }
184
185 SYSCALL_DEFINE4(utimensat, int, dfd, const char __user *, filename,
186                 struct timespec __user *, utimes, int, flags)
187 {
188         struct timespec tstimes[2];
189
190         if (utimes) {
191                 if (copy_from_user(&tstimes, utimes, sizeof(tstimes)))
192                         return -EFAULT;
193
194                 /* Nothing to do, we must not even check the path.  */
195                 if (tstimes[0].tv_nsec == UTIME_OMIT &&
196                     tstimes[1].tv_nsec == UTIME_OMIT)
197                         return 0;
198         }
199
200         return do_utimes(dfd, filename, utimes ? tstimes : NULL, flags);
201 }
202
203 SYSCALL_DEFINE3(futimesat, int, dfd, const char __user *, filename,
204                 struct timeval __user *, utimes)
205 {
206         struct timeval times[2];
207         struct timespec tstimes[2];
208
209         if (utimes) {
210                 if (copy_from_user(&times, utimes, sizeof(times)))
211                         return -EFAULT;
212
213                 /* This test is needed to catch all invalid values.  If we
214                    would test only in do_utimes we would miss those invalid
215                    values truncated by the multiplication with 1000.  Note
216                    that we also catch UTIME_{NOW,OMIT} here which are only
217                    valid for utimensat.  */
218                 if (times[0].tv_usec >= 1000000 || times[0].tv_usec < 0 ||
219                     times[1].tv_usec >= 1000000 || times[1].tv_usec < 0)
220                         return -EINVAL;
221
222                 tstimes[0].tv_sec = times[0].tv_sec;
223                 tstimes[0].tv_nsec = 1000 * times[0].tv_usec;
224                 tstimes[1].tv_sec = times[1].tv_sec;
225                 tstimes[1].tv_nsec = 1000 * times[1].tv_usec;
226         }
227
228         return do_utimes(dfd, filename, utimes ? tstimes : NULL, 0);
229 }
230
231 SYSCALL_DEFINE2(utimes, char __user *, filename,
232                 struct timeval __user *, utimes)
233 {
234         return sys_futimesat(AT_FDCWD, filename, utimes);
235 }