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Commit | Line | Data |
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0226f492 AV |
1 | /* |
2 | * fs/proc_namespace.c - handling of /proc/<pid>/{mounts,mountinfo,mountstats} | |
3 | * | |
4 | * In fact, that's a piece of procfs; it's *almost* isolated from | |
5 | * the rest of fs/proc, but has rather close relationships with | |
6 | * fs/namespace.c, thus here instead of fs/proc | |
7 | * | |
8 | */ | |
9 | #include <linux/mnt_namespace.h> | |
10 | #include <linux/nsproxy.h> | |
11 | #include <linux/security.h> | |
12 | #include <linux/fs_struct.h> | |
f719ff9b IM |
13 | #include <linux/sched/task.h> |
14 | ||
0226f492 AV |
15 | #include "proc/internal.h" /* only for get_proc_task() in ->open() */ |
16 | ||
17 | #include "pnode.h" | |
18 | #include "internal.h" | |
19 | ||
20 | static unsigned mounts_poll(struct file *file, poll_table *wait) | |
21 | { | |
ede1bf0d YD |
22 | struct seq_file *m = file->private_data; |
23 | struct proc_mounts *p = m->private; | |
0226f492 AV |
24 | struct mnt_namespace *ns = p->ns; |
25 | unsigned res = POLLIN | POLLRDNORM; | |
aab407fc | 26 | int event; |
0226f492 AV |
27 | |
28 | poll_wait(file, &p->ns->poll, wait); | |
29 | ||
6aa7de05 | 30 | event = READ_ONCE(ns->event); |
ede1bf0d YD |
31 | if (m->poll_event != event) { |
32 | m->poll_event = event; | |
0226f492 AV |
33 | res |= POLLERR | POLLPRI; |
34 | } | |
0226f492 AV |
35 | |
36 | return res; | |
37 | } | |
38 | ||
39 | struct proc_fs_info { | |
40 | int flag; | |
41 | const char *str; | |
42 | }; | |
43 | ||
44 | static int show_sb_opts(struct seq_file *m, struct super_block *sb) | |
45 | { | |
46 | static const struct proc_fs_info fs_info[] = { | |
47 | { MS_SYNCHRONOUS, ",sync" }, | |
48 | { MS_DIRSYNC, ",dirsync" }, | |
49 | { MS_MANDLOCK, ",mand" }, | |
0ae45f63 | 50 | { MS_LAZYTIME, ",lazytime" }, |
0226f492 AV |
51 | { 0, NULL } |
52 | }; | |
53 | const struct proc_fs_info *fs_infop; | |
54 | ||
55 | for (fs_infop = fs_info; fs_infop->flag; fs_infop++) { | |
56 | if (sb->s_flags & fs_infop->flag) | |
57 | seq_puts(m, fs_infop->str); | |
58 | } | |
59 | ||
60 | return security_sb_show_options(m, sb); | |
61 | } | |
62 | ||
63 | static void show_mnt_opts(struct seq_file *m, struct vfsmount *mnt) | |
64 | { | |
65 | static const struct proc_fs_info mnt_info[] = { | |
66 | { MNT_NOSUID, ",nosuid" }, | |
67 | { MNT_NODEV, ",nodev" }, | |
68 | { MNT_NOEXEC, ",noexec" }, | |
69 | { MNT_NOATIME, ",noatime" }, | |
70 | { MNT_NODIRATIME, ",nodiratime" }, | |
71 | { MNT_RELATIME, ",relatime" }, | |
72 | { 0, NULL } | |
73 | }; | |
74 | const struct proc_fs_info *fs_infop; | |
75 | ||
76 | for (fs_infop = mnt_info; fs_infop->flag; fs_infop++) { | |
77 | if (mnt->mnt_flags & fs_infop->flag) | |
78 | seq_puts(m, fs_infop->str); | |
79 | } | |
80 | } | |
81 | ||
82 | static inline void mangle(struct seq_file *m, const char *s) | |
83 | { | |
84 | seq_escape(m, s, " \t\n\\"); | |
85 | } | |
86 | ||
87 | static void show_type(struct seq_file *m, struct super_block *sb) | |
88 | { | |
89 | mangle(m, sb->s_type->name); | |
90 | if (sb->s_subtype && sb->s_subtype[0]) { | |
91 | seq_putc(m, '.'); | |
92 | mangle(m, sb->s_subtype); | |
93 | } | |
94 | } | |
95 | ||
96 | static int show_vfsmnt(struct seq_file *m, struct vfsmount *mnt) | |
97 | { | |
ede1bf0d | 98 | struct proc_mounts *p = m->private; |
0226f492 | 99 | struct mount *r = real_mount(mnt); |
0226f492 | 100 | struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt }; |
d861c630 | 101 | struct super_block *sb = mnt_path.dentry->d_sb; |
5d9f3c7b | 102 | int err; |
0226f492 | 103 | |
d861c630 AV |
104 | if (sb->s_op->show_devname) { |
105 | err = sb->s_op->show_devname(m, mnt_path.dentry); | |
0226f492 AV |
106 | if (err) |
107 | goto out; | |
108 | } else { | |
109 | mangle(m, r->mnt_devname ? r->mnt_devname : "none"); | |
110 | } | |
111 | seq_putc(m, ' '); | |
9d4d6574 DL |
112 | /* mountpoints outside of chroot jail will give SEQ_SKIP on this */ |
113 | err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\"); | |
114 | if (err) | |
115 | goto out; | |
0226f492 | 116 | seq_putc(m, ' '); |
d861c630 | 117 | show_type(m, sb); |
0226f492 | 118 | seq_puts(m, __mnt_is_readonly(mnt) ? " ro" : " rw"); |
d861c630 | 119 | err = show_sb_opts(m, sb); |
0226f492 AV |
120 | if (err) |
121 | goto out; | |
122 | show_mnt_opts(m, mnt); | |
d861c630 | 123 | if (sb->s_op->show_options) |
34c80b1d | 124 | err = sb->s_op->show_options(m, mnt_path.dentry); |
0226f492 AV |
125 | seq_puts(m, " 0 0\n"); |
126 | out: | |
127 | return err; | |
128 | } | |
129 | ||
130 | static int show_mountinfo(struct seq_file *m, struct vfsmount *mnt) | |
131 | { | |
ede1bf0d | 132 | struct proc_mounts *p = m->private; |
0226f492 AV |
133 | struct mount *r = real_mount(mnt); |
134 | struct super_block *sb = mnt->mnt_sb; | |
135 | struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt }; | |
6ce4bca0 | 136 | int err; |
0226f492 AV |
137 | |
138 | seq_printf(m, "%i %i %u:%u ", r->mnt_id, r->mnt_parent->mnt_id, | |
139 | MAJOR(sb->s_dev), MINOR(sb->s_dev)); | |
6ce4bca0 | 140 | if (sb->s_op->show_path) { |
a6322de6 | 141 | err = sb->s_op->show_path(m, mnt->mnt_root); |
6ce4bca0 DL |
142 | if (err) |
143 | goto out; | |
144 | } else { | |
0226f492 | 145 | seq_dentry(m, mnt->mnt_root, " \t\n\\"); |
6ce4bca0 | 146 | } |
0226f492 AV |
147 | seq_putc(m, ' '); |
148 | ||
149 | /* mountpoints outside of chroot jail will give SEQ_SKIP on this */ | |
9ad4dc4f | 150 | err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\"); |
0226f492 AV |
151 | if (err) |
152 | goto out; | |
153 | ||
154 | seq_puts(m, mnt->mnt_flags & MNT_READONLY ? " ro" : " rw"); | |
155 | show_mnt_opts(m, mnt); | |
156 | ||
157 | /* Tagged fields ("foo:X" or "bar") */ | |
158 | if (IS_MNT_SHARED(r)) | |
159 | seq_printf(m, " shared:%i", r->mnt_group_id); | |
160 | if (IS_MNT_SLAVE(r)) { | |
161 | int master = r->mnt_master->mnt_group_id; | |
162 | int dom = get_dominating_id(r, &p->root); | |
163 | seq_printf(m, " master:%i", master); | |
164 | if (dom && dom != master) | |
165 | seq_printf(m, " propagate_from:%i", dom); | |
166 | } | |
167 | if (IS_MNT_UNBINDABLE(r)) | |
168 | seq_puts(m, " unbindable"); | |
169 | ||
170 | /* Filesystem specific data */ | |
171 | seq_puts(m, " - "); | |
172 | show_type(m, sb); | |
173 | seq_putc(m, ' '); | |
6ce4bca0 | 174 | if (sb->s_op->show_devname) { |
d861c630 | 175 | err = sb->s_op->show_devname(m, mnt->mnt_root); |
6ce4bca0 DL |
176 | if (err) |
177 | goto out; | |
178 | } else { | |
0226f492 | 179 | mangle(m, r->mnt_devname ? r->mnt_devname : "none"); |
6ce4bca0 | 180 | } |
bc98a42c | 181 | seq_puts(m, sb_rdonly(sb) ? " ro" : " rw"); |
0226f492 AV |
182 | err = show_sb_opts(m, sb); |
183 | if (err) | |
184 | goto out; | |
185 | if (sb->s_op->show_options) | |
34c80b1d | 186 | err = sb->s_op->show_options(m, mnt->mnt_root); |
0226f492 AV |
187 | seq_putc(m, '\n'); |
188 | out: | |
189 | return err; | |
190 | } | |
191 | ||
192 | static int show_vfsstat(struct seq_file *m, struct vfsmount *mnt) | |
193 | { | |
ede1bf0d | 194 | struct proc_mounts *p = m->private; |
0226f492 AV |
195 | struct mount *r = real_mount(mnt); |
196 | struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt }; | |
64132379 | 197 | struct super_block *sb = mnt_path.dentry->d_sb; |
b896fb35 | 198 | int err; |
0226f492 AV |
199 | |
200 | /* device */ | |
64132379 | 201 | if (sb->s_op->show_devname) { |
0226f492 | 202 | seq_puts(m, "device "); |
d861c630 | 203 | err = sb->s_op->show_devname(m, mnt_path.dentry); |
5f8d498d DL |
204 | if (err) |
205 | goto out; | |
0226f492 AV |
206 | } else { |
207 | if (r->mnt_devname) { | |
208 | seq_puts(m, "device "); | |
209 | mangle(m, r->mnt_devname); | |
210 | } else | |
211 | seq_puts(m, "no device"); | |
212 | } | |
213 | ||
214 | /* mount point */ | |
215 | seq_puts(m, " mounted on "); | |
9d4d6574 DL |
216 | /* mountpoints outside of chroot jail will give SEQ_SKIP on this */ |
217 | err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\"); | |
218 | if (err) | |
219 | goto out; | |
0226f492 AV |
220 | seq_putc(m, ' '); |
221 | ||
222 | /* file system type */ | |
223 | seq_puts(m, "with fstype "); | |
64132379 | 224 | show_type(m, sb); |
0226f492 AV |
225 | |
226 | /* optional statistics */ | |
64132379 | 227 | if (sb->s_op->show_stats) { |
0226f492 | 228 | seq_putc(m, ' '); |
b896fb35 | 229 | err = sb->s_op->show_stats(m, mnt_path.dentry); |
0226f492 AV |
230 | } |
231 | ||
232 | seq_putc(m, '\n'); | |
9d4d6574 | 233 | out: |
0226f492 AV |
234 | return err; |
235 | } | |
236 | ||
237 | static int mounts_open_common(struct inode *inode, struct file *file, | |
238 | int (*show)(struct seq_file *, struct vfsmount *)) | |
239 | { | |
240 | struct task_struct *task = get_proc_task(inode); | |
241 | struct nsproxy *nsp; | |
242 | struct mnt_namespace *ns = NULL; | |
243 | struct path root; | |
244 | struct proc_mounts *p; | |
ede1bf0d | 245 | struct seq_file *m; |
0226f492 AV |
246 | int ret = -EINVAL; |
247 | ||
248 | if (!task) | |
249 | goto err; | |
250 | ||
728dba3a EB |
251 | task_lock(task); |
252 | nsp = task->nsproxy; | |
3d93116c | 253 | if (!nsp || !nsp->mnt_ns) { |
728dba3a | 254 | task_unlock(task); |
0226f492 AV |
255 | put_task_struct(task); |
256 | goto err; | |
257 | } | |
258 | ns = nsp->mnt_ns; | |
0226f492 | 259 | get_mnt_ns(ns); |
0226f492 AV |
260 | if (!task->fs) { |
261 | task_unlock(task); | |
262 | put_task_struct(task); | |
263 | ret = -ENOENT; | |
264 | goto err_put_ns; | |
265 | } | |
266 | get_fs_root(task->fs, &root); | |
267 | task_unlock(task); | |
268 | put_task_struct(task); | |
269 | ||
ede1bf0d YD |
270 | ret = seq_open_private(file, &mounts_op, sizeof(struct proc_mounts)); |
271 | if (ret) | |
0226f492 AV |
272 | goto err_put_path; |
273 | ||
ede1bf0d YD |
274 | m = file->private_data; |
275 | m->poll_event = ns->event; | |
0226f492 | 276 | |
ede1bf0d | 277 | p = m->private; |
0226f492 AV |
278 | p->ns = ns; |
279 | p->root = root; | |
0226f492 | 280 | p->show = show; |
c7999c36 | 281 | p->cached_event = ~0ULL; |
0226f492 AV |
282 | |
283 | return 0; | |
284 | ||
0226f492 AV |
285 | err_put_path: |
286 | path_put(&root); | |
287 | err_put_ns: | |
288 | put_mnt_ns(ns); | |
289 | err: | |
290 | return ret; | |
291 | } | |
292 | ||
293 | static int mounts_release(struct inode *inode, struct file *file) | |
294 | { | |
ede1bf0d YD |
295 | struct seq_file *m = file->private_data; |
296 | struct proc_mounts *p = m->private; | |
0226f492 AV |
297 | path_put(&p->root); |
298 | put_mnt_ns(p->ns); | |
ede1bf0d | 299 | return seq_release_private(inode, file); |
0226f492 AV |
300 | } |
301 | ||
302 | static int mounts_open(struct inode *inode, struct file *file) | |
303 | { | |
304 | return mounts_open_common(inode, file, show_vfsmnt); | |
305 | } | |
306 | ||
307 | static int mountinfo_open(struct inode *inode, struct file *file) | |
308 | { | |
309 | return mounts_open_common(inode, file, show_mountinfo); | |
310 | } | |
311 | ||
312 | static int mountstats_open(struct inode *inode, struct file *file) | |
313 | { | |
314 | return mounts_open_common(inode, file, show_vfsstat); | |
315 | } | |
316 | ||
317 | const struct file_operations proc_mounts_operations = { | |
318 | .open = mounts_open, | |
319 | .read = seq_read, | |
320 | .llseek = seq_lseek, | |
321 | .release = mounts_release, | |
322 | .poll = mounts_poll, | |
323 | }; | |
324 | ||
325 | const struct file_operations proc_mountinfo_operations = { | |
326 | .open = mountinfo_open, | |
327 | .read = seq_read, | |
328 | .llseek = seq_lseek, | |
329 | .release = mounts_release, | |
330 | .poll = mounts_poll, | |
331 | }; | |
332 | ||
333 | const struct file_operations proc_mountstats_operations = { | |
334 | .open = mountstats_open, | |
335 | .read = seq_read, | |
336 | .llseek = seq_lseek, | |
337 | .release = mounts_release, | |
338 | }; |