blob: 6863773aff252796e72f1bc3083869cc99b40fb5
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> |
13 | #include "proc/internal.h" /* only for get_proc_task() in ->open() */ |
14 | |
15 | #include "pnode.h" |
16 | #include "internal.h" |
17 | |
18 | static unsigned mounts_poll(struct file *file, poll_table *wait) |
19 | { |
20 | struct seq_file *m = file->private_data; |
21 | struct proc_mounts *p = m->private; |
22 | struct mnt_namespace *ns = p->ns; |
23 | unsigned res = POLLIN | POLLRDNORM; |
24 | int event; |
25 | |
26 | poll_wait(file, &p->ns->poll, wait); |
27 | |
28 | event = ACCESS_ONCE(ns->event); |
29 | if (m->poll_event != event) { |
30 | m->poll_event = event; |
31 | res |= POLLERR | POLLPRI; |
32 | } |
33 | |
34 | return res; |
35 | } |
36 | |
37 | struct proc_fs_info { |
38 | int flag; |
39 | const char *str; |
40 | }; |
41 | |
42 | static int show_sb_opts(struct seq_file *m, struct super_block *sb) |
43 | { |
44 | static const struct proc_fs_info fs_info[] = { |
45 | { MS_SYNCHRONOUS, ",sync" }, |
46 | { MS_DIRSYNC, ",dirsync" }, |
47 | { MS_MANDLOCK, ",mand" }, |
48 | { MS_LAZYTIME, ",lazytime" }, |
49 | { 0, NULL } |
50 | }; |
51 | const struct proc_fs_info *fs_infop; |
52 | |
53 | for (fs_infop = fs_info; fs_infop->flag; fs_infop++) { |
54 | if (sb->s_flags & fs_infop->flag) |
55 | seq_puts(m, fs_infop->str); |
56 | } |
57 | |
58 | return security_sb_show_options(m, sb); |
59 | } |
60 | |
61 | static void show_mnt_opts(struct seq_file *m, struct vfsmount *mnt) |
62 | { |
63 | static const struct proc_fs_info mnt_info[] = { |
64 | { MNT_NOSUID, ",nosuid" }, |
65 | { MNT_NODEV, ",nodev" }, |
66 | { MNT_NOEXEC, ",noexec" }, |
67 | { MNT_NOATIME, ",noatime" }, |
68 | { MNT_NODIRATIME, ",nodiratime" }, |
69 | { MNT_RELATIME, ",relatime" }, |
70 | { 0, NULL } |
71 | }; |
72 | const struct proc_fs_info *fs_infop; |
73 | |
74 | for (fs_infop = mnt_info; fs_infop->flag; fs_infop++) { |
75 | if (mnt->mnt_flags & fs_infop->flag) |
76 | seq_puts(m, fs_infop->str); |
77 | } |
78 | } |
79 | |
80 | static inline void mangle(struct seq_file *m, const char *s) |
81 | { |
82 | seq_escape(m, s, " \t\n\\"); |
83 | } |
84 | |
85 | static void show_type(struct seq_file *m, struct super_block *sb) |
86 | { |
87 | mangle(m, sb->s_type->name); |
88 | if (sb->s_subtype && sb->s_subtype[0]) { |
89 | seq_putc(m, '.'); |
90 | mangle(m, sb->s_subtype); |
91 | } |
92 | } |
93 | |
94 | static int show_vfsmnt(struct seq_file *m, struct vfsmount *mnt) |
95 | { |
96 | struct proc_mounts *p = m->private; |
97 | struct mount *r = real_mount(mnt); |
98 | struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt }; |
99 | struct super_block *sb = mnt_path.dentry->d_sb; |
100 | int err; |
101 | |
102 | if (sb->s_op->show_devname) { |
103 | err = sb->s_op->show_devname(m, mnt_path.dentry); |
104 | if (err) |
105 | goto out; |
106 | } else { |
107 | mangle(m, r->mnt_devname ? r->mnt_devname : "none"); |
108 | } |
109 | seq_putc(m, ' '); |
110 | /* mountpoints outside of chroot jail will give SEQ_SKIP on this */ |
111 | err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\"); |
112 | if (err) |
113 | goto out; |
114 | seq_putc(m, ' '); |
115 | show_type(m, sb); |
116 | seq_puts(m, __mnt_is_readonly(mnt) ? " ro" : " rw"); |
117 | err = show_sb_opts(m, sb); |
118 | if (err) |
119 | goto out; |
120 | show_mnt_opts(m, mnt); |
121 | if (sb->s_op->show_options2) |
122 | err = sb->s_op->show_options2(mnt, m, mnt_path.dentry); |
123 | else if (sb->s_op->show_options) |
124 | err = sb->s_op->show_options(m, mnt_path.dentry); |
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 | { |
132 | struct proc_mounts *p = m->private; |
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 }; |
136 | int err; |
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)); |
140 | if (sb->s_op->show_path) { |
141 | err = sb->s_op->show_path(m, mnt->mnt_root); |
142 | if (err) |
143 | goto out; |
144 | } else { |
145 | seq_dentry(m, mnt->mnt_root, " \t\n\\"); |
146 | } |
147 | seq_putc(m, ' '); |
148 | |
149 | /* mountpoints outside of chroot jail will give SEQ_SKIP on this */ |
150 | err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\"); |
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, ' '); |
174 | if (sb->s_op->show_devname) { |
175 | err = sb->s_op->show_devname(m, mnt->mnt_root); |
176 | if (err) |
177 | goto out; |
178 | } else { |
179 | mangle(m, r->mnt_devname ? r->mnt_devname : "none"); |
180 | } |
181 | seq_puts(m, sb->s_flags & MS_RDONLY ? " ro" : " rw"); |
182 | err = show_sb_opts(m, sb); |
183 | if (err) |
184 | goto out; |
185 | if (sb->s_op->show_options2) { |
186 | err = sb->s_op->show_options2(mnt, m, mnt->mnt_root); |
187 | } else if (sb->s_op->show_options) |
188 | err = sb->s_op->show_options(m, mnt->mnt_root); |
189 | seq_putc(m, '\n'); |
190 | out: |
191 | return err; |
192 | } |
193 | |
194 | static int show_vfsstat(struct seq_file *m, struct vfsmount *mnt) |
195 | { |
196 | struct proc_mounts *p = m->private; |
197 | struct mount *r = real_mount(mnt); |
198 | struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt }; |
199 | struct super_block *sb = mnt_path.dentry->d_sb; |
200 | int err; |
201 | |
202 | /* device */ |
203 | if (sb->s_op->show_devname) { |
204 | seq_puts(m, "device "); |
205 | err = sb->s_op->show_devname(m, mnt_path.dentry); |
206 | if (err) |
207 | goto out; |
208 | } else { |
209 | if (r->mnt_devname) { |
210 | seq_puts(m, "device "); |
211 | mangle(m, r->mnt_devname); |
212 | } else |
213 | seq_puts(m, "no device"); |
214 | } |
215 | |
216 | /* mount point */ |
217 | seq_puts(m, " mounted on "); |
218 | /* mountpoints outside of chroot jail will give SEQ_SKIP on this */ |
219 | err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\"); |
220 | if (err) |
221 | goto out; |
222 | seq_putc(m, ' '); |
223 | |
224 | /* file system type */ |
225 | seq_puts(m, "with fstype "); |
226 | show_type(m, sb); |
227 | |
228 | /* optional statistics */ |
229 | if (sb->s_op->show_stats) { |
230 | seq_putc(m, ' '); |
231 | err = sb->s_op->show_stats(m, mnt_path.dentry); |
232 | } |
233 | |
234 | seq_putc(m, '\n'); |
235 | out: |
236 | return err; |
237 | } |
238 | |
239 | static int mounts_open_common(struct inode *inode, struct file *file, |
240 | int (*show)(struct seq_file *, struct vfsmount *)) |
241 | { |
242 | struct task_struct *task = get_proc_task(inode); |
243 | struct nsproxy *nsp; |
244 | struct mnt_namespace *ns = NULL; |
245 | struct path root; |
246 | struct proc_mounts *p; |
247 | struct seq_file *m; |
248 | int ret = -EINVAL; |
249 | |
250 | if (!task) |
251 | goto err; |
252 | |
253 | task_lock(task); |
254 | nsp = task->nsproxy; |
255 | if (!nsp || !nsp->mnt_ns) { |
256 | task_unlock(task); |
257 | put_task_struct(task); |
258 | goto err; |
259 | } |
260 | ns = nsp->mnt_ns; |
261 | get_mnt_ns(ns); |
262 | if (!task->fs) { |
263 | task_unlock(task); |
264 | put_task_struct(task); |
265 | ret = -ENOENT; |
266 | goto err_put_ns; |
267 | } |
268 | get_fs_root(task->fs, &root); |
269 | task_unlock(task); |
270 | put_task_struct(task); |
271 | |
272 | ret = seq_open_private(file, &mounts_op, sizeof(struct proc_mounts)); |
273 | if (ret) |
274 | goto err_put_path; |
275 | |
276 | m = file->private_data; |
277 | m->poll_event = ns->event; |
278 | |
279 | p = m->private; |
280 | p->ns = ns; |
281 | p->root = root; |
282 | p->show = show; |
283 | p->cached_event = ~0ULL; |
284 | |
285 | return 0; |
286 | |
287 | err_put_path: |
288 | path_put(&root); |
289 | err_put_ns: |
290 | put_mnt_ns(ns); |
291 | err: |
292 | return ret; |
293 | } |
294 | |
295 | static int mounts_release(struct inode *inode, struct file *file) |
296 | { |
297 | struct seq_file *m = file->private_data; |
298 | struct proc_mounts *p = m->private; |
299 | path_put(&p->root); |
300 | put_mnt_ns(p->ns); |
301 | return seq_release_private(inode, file); |
302 | } |
303 | |
304 | static int mounts_open(struct inode *inode, struct file *file) |
305 | { |
306 | return mounts_open_common(inode, file, show_vfsmnt); |
307 | } |
308 | |
309 | static int mountinfo_open(struct inode *inode, struct file *file) |
310 | { |
311 | return mounts_open_common(inode, file, show_mountinfo); |
312 | } |
313 | |
314 | static int mountstats_open(struct inode *inode, struct file *file) |
315 | { |
316 | return mounts_open_common(inode, file, show_vfsstat); |
317 | } |
318 | |
319 | const struct file_operations proc_mounts_operations = { |
320 | .open = mounts_open, |
321 | .read = seq_read, |
322 | .llseek = seq_lseek, |
323 | .release = mounts_release, |
324 | .poll = mounts_poll, |
325 | }; |
326 | |
327 | const struct file_operations proc_mountinfo_operations = { |
328 | .open = mountinfo_open, |
329 | .read = seq_read, |
330 | .llseek = seq_lseek, |
331 | .release = mounts_release, |
332 | .poll = mounts_poll, |
333 | }; |
334 | |
335 | const struct file_operations proc_mountstats_operations = { |
336 | .open = mountstats_open, |
337 | .read = seq_read, |
338 | .llseek = seq_lseek, |
339 | .release = mounts_release, |
340 | }; |
341 |