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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 */
27SYSCALL_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, ×->actime) ||
33 get_user(tv[1].tv_sec, ×->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
43static 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
51static 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
57 error = mnt_want_write(path->mnt);
58 if (error)
59 goto out;
60
61 if (times && times[0].tv_nsec == UTIME_NOW &&
62 times[1].tv_nsec == UTIME_NOW)
63 times = NULL;
64
65 newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME;
66 if (times) {
67 if (times[0].tv_nsec == UTIME_OMIT)
68 newattrs.ia_valid &= ~ATTR_ATIME;
69 else if (times[0].tv_nsec != UTIME_NOW) {
70 newattrs.ia_atime.tv_sec = times[0].tv_sec;
71 newattrs.ia_atime.tv_nsec = times[0].tv_nsec;
72 newattrs.ia_valid |= ATTR_ATIME_SET;
73 }
74
75 if (times[1].tv_nsec == UTIME_OMIT)
76 newattrs.ia_valid &= ~ATTR_MTIME;
77 else if (times[1].tv_nsec != UTIME_NOW) {
78 newattrs.ia_mtime.tv_sec = times[1].tv_sec;
79 newattrs.ia_mtime.tv_nsec = times[1].tv_nsec;
80 newattrs.ia_valid |= ATTR_MTIME_SET;
81 }
82 /*
83 * Tell inode_change_ok(), that this is an explicit time
84 * update, even if neither ATTR_ATIME_SET nor ATTR_MTIME_SET
85 * were used.
86 */
87 newattrs.ia_valid |= ATTR_TIMES_SET;
88 } else {
89 /*
90 * If times is NULL (or both times are UTIME_NOW),
91 * then we need to check permissions, because
92 * inode_change_ok() won't do it.
93 */
94 error = -EACCES;
95 if (IS_IMMUTABLE(inode))
96 goto mnt_drop_write_and_out;
97
98 if (!inode_owner_or_capable(inode)) {
99 error = inode_permission(inode, MAY_WRITE);
100 if (error)
101 goto mnt_drop_write_and_out;
102 }
103 }
104 mutex_lock(&inode->i_mutex);
105 error = notify_change(path->dentry, &newattrs);
106 mutex_unlock(&inode->i_mutex);
107
108mnt_drop_write_and_out:
109 mnt_drop_write(path->mnt);
110out:
111 return error;
112}
113
114/*
115 * do_utimes - change times on filename or file descriptor
116 * @dfd: open file descriptor, -1 or AT_FDCWD
117 * @filename: path name or NULL
118 * @times: new times or NULL
119 * @flags: zero or more flags (only AT_SYMLINK_NOFOLLOW for the moment)
120 *
121 * If filename is NULL and dfd refers to an open file, then operate on
122 * the file. Otherwise look up filename, possibly using dfd as a
123 * starting point.
124 *
125 * If times==NULL, set access and modification to current time,
126 * must be owner or have write permission.
127 * Else, update from *times, must be owner or super user.
128 */
129long do_utimes(int dfd, const char __user *filename, struct timespec *times,
130 int flags)
131{
132 int error = -EINVAL;
133
134 if (times && (!nsec_valid(times[0].tv_nsec) ||
135 !nsec_valid(times[1].tv_nsec))) {
136 goto out;
137 }
138
139 if (flags & ~AT_SYMLINK_NOFOLLOW)
140 goto out;
141
142 if (filename == NULL && dfd != AT_FDCWD) {
143 struct file *file;
144
145 if (flags & AT_SYMLINK_NOFOLLOW)
146 goto out;
147
148 file = fget(dfd);
149 error = -EBADF;
150 if (!file)
151 goto out;
152
153 error = utimes_common(&file->f_path, times);
154 fput(file);
155 } else {
156 struct path path;
157 int lookup_flags = 0;
158
159 if (!(flags & AT_SYMLINK_NOFOLLOW))
160 lookup_flags |= LOOKUP_FOLLOW;
161
162 error = user_path_at(dfd, filename, lookup_flags, &path);
163 if (error)
164 goto out;
165
166 error = utimes_common(&path, times);
167 path_put(&path);
168 }
169
170out:
171 return error;
172}
173
174SYSCALL_DEFINE4(utimensat, int, dfd, const char __user *, filename,
175 struct timespec __user *, utimes, int, flags)
176{
177 struct timespec tstimes[2];
178
179 if (utimes) {
180 if (copy_from_user(&tstimes, utimes, sizeof(tstimes)))
181 return -EFAULT;
182
183 /* Nothing to do, we must not even check the path. */
184 if (tstimes[0].tv_nsec == UTIME_OMIT &&
185 tstimes[1].tv_nsec == UTIME_OMIT)
186 return 0;
187 }
188
189 return do_utimes(dfd, filename, utimes ? tstimes : NULL, flags);
190}
191
192SYSCALL_DEFINE3(futimesat, int, dfd, const char __user *, filename,
193 struct timeval __user *, utimes)
194{
195 struct timeval times[2];
196 struct timespec tstimes[2];
197
198 if (utimes) {
199 if (copy_from_user(×, utimes, sizeof(times)))
200 return -EFAULT;
201
202 /* This test is needed to catch all invalid values. If we
203 would test only in do_utimes we would miss those invalid
204 values truncated by the multiplication with 1000. Note
205 that we also catch UTIME_{NOW,OMIT} here which are only
206 valid for utimensat. */
207 if (times[0].tv_usec >= 1000000 || times[0].tv_usec < 0 ||
208 times[1].tv_usec >= 1000000 || times[1].tv_usec < 0)
209 return -EINVAL;
210
211 tstimes[0].tv_sec = times[0].tv_sec;
212 tstimes[0].tv_nsec = 1000 * times[0].tv_usec;
213 tstimes[1].tv_sec = times[1].tv_sec;
214 tstimes[1].tv_nsec = 1000 * times[1].tv_usec;
215 }
216
217 return do_utimes(dfd, filename, utimes ? tstimes : NULL, 0);
218}
219
220SYSCALL_DEFINE2(utimes, char __user *, filename,
221 struct timeval __user *, utimes)
222{
223 return sys_futimesat(AT_FDCWD, filename, utimes);
224}
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 */
27SYSCALL_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, ×->actime) ||
33 get_user(tv[1].tv_sec, ×->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
43static 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
51static 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
57 error = mnt_want_write(path->mnt);
58 if (error)
59 goto out;
60
61 if (times && times[0].tv_nsec == UTIME_NOW &&
62 times[1].tv_nsec == UTIME_NOW)
63 times = NULL;
64
65 newattrs.ia_valid = ATTR_CTIME | ATTR_MTIME | ATTR_ATIME;
66 if (times) {
67 if (times[0].tv_nsec == UTIME_OMIT)
68 newattrs.ia_valid &= ~ATTR_ATIME;
69 else if (times[0].tv_nsec != UTIME_NOW) {
70 newattrs.ia_atime.tv_sec = times[0].tv_sec;
71 newattrs.ia_atime.tv_nsec = times[0].tv_nsec;
72 newattrs.ia_valid |= ATTR_ATIME_SET;
73 }
74
75 if (times[1].tv_nsec == UTIME_OMIT)
76 newattrs.ia_valid &= ~ATTR_MTIME;
77 else if (times[1].tv_nsec != UTIME_NOW) {
78 newattrs.ia_mtime.tv_sec = times[1].tv_sec;
79 newattrs.ia_mtime.tv_nsec = times[1].tv_nsec;
80 newattrs.ia_valid |= ATTR_MTIME_SET;
81 }
82 /*
83 * Tell inode_change_ok(), that this is an explicit time
84 * update, even if neither ATTR_ATIME_SET nor ATTR_MTIME_SET
85 * were used.
86 */
87 newattrs.ia_valid |= ATTR_TIMES_SET;
88 } else {
89 /*
90 * If times is NULL (or both times are UTIME_NOW),
91 * then we need to check permissions, because
92 * inode_change_ok() won't do it.
93 */
94 error = -EACCES;
95 if (IS_IMMUTABLE(inode))
96 goto mnt_drop_write_and_out;
97
98 if (!inode_owner_or_capable(inode)) {
99 error = inode_permission(inode, MAY_WRITE);
100 if (error)
101 goto mnt_drop_write_and_out;
102 }
103 }
104 mutex_lock(&inode->i_mutex);
105 error = notify_change(path->dentry, &newattrs);
106 mutex_unlock(&inode->i_mutex);
107
108mnt_drop_write_and_out:
109 mnt_drop_write(path->mnt);
110out:
111 return error;
112}
113
114/*
115 * do_utimes - change times on filename or file descriptor
116 * @dfd: open file descriptor, -1 or AT_FDCWD
117 * @filename: path name or NULL
118 * @times: new times or NULL
119 * @flags: zero or more flags (only AT_SYMLINK_NOFOLLOW for the moment)
120 *
121 * If filename is NULL and dfd refers to an open file, then operate on
122 * the file. Otherwise look up filename, possibly using dfd as a
123 * starting point.
124 *
125 * If times==NULL, set access and modification to current time,
126 * must be owner or have write permission.
127 * Else, update from *times, must be owner or super user.
128 */
129long do_utimes(int dfd, const char __user *filename, struct timespec *times,
130 int flags)
131{
132 int error = -EINVAL;
133
134 if (times && (!nsec_valid(times[0].tv_nsec) ||
135 !nsec_valid(times[1].tv_nsec))) {
136 goto out;
137 }
138
139 if (flags & ~AT_SYMLINK_NOFOLLOW)
140 goto out;
141
142 if (filename == NULL && dfd != AT_FDCWD) {
143 int fput_needed;
144 struct file *file;
145
146 if (flags & AT_SYMLINK_NOFOLLOW)
147 goto out;
148
149 file = fget_light(dfd, &fput_needed);
150 error = -EBADF;
151 if (!file)
152 goto out;
153
154 error = utimes_common(&file->f_path, times);
155 fput_light(file, fput_needed);
156 } else {
157 struct path path;
158 int lookup_flags = 0;
159
160 if (!(flags & AT_SYMLINK_NOFOLLOW))
161 lookup_flags |= LOOKUP_FOLLOW;
162
163 error = user_path_at(dfd, filename, lookup_flags, &path);
164 if (error)
165 goto out;
166
167 error = utimes_common(&path, times);
168 path_put(&path);
169 }
170
171out:
172 return error;
173}
174
175SYSCALL_DEFINE4(utimensat, int, dfd, const char __user *, filename,
176 struct timespec __user *, utimes, int, flags)
177{
178 struct timespec tstimes[2];
179
180 if (utimes) {
181 if (copy_from_user(&tstimes, utimes, sizeof(tstimes)))
182 return -EFAULT;
183
184 /* Nothing to do, we must not even check the path. */
185 if (tstimes[0].tv_nsec == UTIME_OMIT &&
186 tstimes[1].tv_nsec == UTIME_OMIT)
187 return 0;
188 }
189
190 return do_utimes(dfd, filename, utimes ? tstimes : NULL, flags);
191}
192
193SYSCALL_DEFINE3(futimesat, int, dfd, const char __user *, filename,
194 struct timeval __user *, utimes)
195{
196 struct timeval times[2];
197 struct timespec tstimes[2];
198
199 if (utimes) {
200 if (copy_from_user(×, utimes, sizeof(times)))
201 return -EFAULT;
202
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)
210 return -EINVAL;
211
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;
216 }
217
218 return do_utimes(dfd, filename, utimes ? tstimes : NULL, 0);
219}
220
221SYSCALL_DEFINE2(utimes, char __user *, filename,
222 struct timeval __user *, utimes)
223{
224 return sys_futimesat(AT_FDCWD, filename, utimes);
225}