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