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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 = proc_mounts(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 | struct super_block *sb = mnt_path.dentry->d_sb; |
98 | |
99 | if (sb->s_op->show_devname) { |
100 | err = sb->s_op->show_devname(m, mnt_path.dentry); |
101 | if (err) |
102 | goto out; |
103 | } else { |
104 | mangle(m, r->mnt_devname ? r->mnt_devname : "none"); |
105 | } |
106 | seq_putc(m, ' '); |
107 | seq_path(m, &mnt_path, " \t\n\\"); |
108 | seq_putc(m, ' '); |
109 | show_type(m, sb); |
110 | seq_puts(m, __mnt_is_readonly(mnt) ? " ro" : " rw"); |
111 | err = show_sb_opts(m, sb); |
112 | if (err) |
113 | goto out; |
114 | show_mnt_opts(m, mnt); |
115 | if (sb->s_op->show_options) |
116 | err = sb->s_op->show_options(m, mnt_path.dentry); |
117 | seq_puts(m, " 0 0\n"); |
118 | out: |
119 | return err; |
120 | } |
121 | |
122 | static int show_mountinfo(struct seq_file *m, struct vfsmount *mnt) |
123 | { |
124 | struct proc_mounts *p = proc_mounts(m); |
125 | struct mount *r = real_mount(mnt); |
126 | struct super_block *sb = mnt->mnt_sb; |
127 | struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt }; |
128 | struct path root = p->root; |
129 | int err = 0; |
130 | |
131 | seq_printf(m, "%i %i %u:%u ", r->mnt_id, r->mnt_parent->mnt_id, |
132 | MAJOR(sb->s_dev), MINOR(sb->s_dev)); |
133 | if (sb->s_op->show_path) |
134 | err = sb->s_op->show_path(m, mnt->mnt_root); |
135 | else |
136 | seq_dentry(m, mnt->mnt_root, " \t\n\\"); |
137 | if (err) |
138 | goto out; |
139 | seq_putc(m, ' '); |
140 | |
141 | /* mountpoints outside of chroot jail will give SEQ_SKIP on this */ |
142 | err = seq_path_root(m, &mnt_path, &root, " \t\n\\"); |
143 | if (err) |
144 | goto out; |
145 | |
146 | seq_puts(m, mnt->mnt_flags & MNT_READONLY ? " ro" : " rw"); |
147 | show_mnt_opts(m, mnt); |
148 | |
149 | /* Tagged fields ("foo:X" or "bar") */ |
150 | if (IS_MNT_SHARED(r)) |
151 | seq_printf(m, " shared:%i", r->mnt_group_id); |
152 | if (IS_MNT_SLAVE(r)) { |
153 | int master = r->mnt_master->mnt_group_id; |
154 | int dom = get_dominating_id(r, &p->root); |
155 | seq_printf(m, " master:%i", master); |
156 | if (dom && dom != master) |
157 | seq_printf(m, " propagate_from:%i", dom); |
158 | } |
159 | if (IS_MNT_UNBINDABLE(r)) |
160 | seq_puts(m, " unbindable"); |
161 | |
162 | /* Filesystem specific data */ |
163 | seq_puts(m, " - "); |
164 | show_type(m, sb); |
165 | seq_putc(m, ' '); |
166 | if (sb->s_op->show_devname) |
167 | err = sb->s_op->show_devname(m, mnt->mnt_root); |
168 | else |
169 | mangle(m, r->mnt_devname ? r->mnt_devname : "none"); |
170 | if (err) |
171 | goto out; |
172 | seq_puts(m, sb->s_flags & MS_RDONLY ? " ro" : " rw"); |
173 | err = show_sb_opts(m, sb); |
174 | if (err) |
175 | goto out; |
176 | if (sb->s_op->show_options) |
177 | err = sb->s_op->show_options(m, mnt->mnt_root); |
178 | seq_putc(m, '\n'); |
179 | out: |
180 | return err; |
181 | } |
182 | |
183 | static int show_vfsstat(struct seq_file *m, struct vfsmount *mnt) |
184 | { |
185 | struct mount *r = real_mount(mnt); |
186 | struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt }; |
187 | struct super_block *sb = mnt_path.dentry->d_sb; |
188 | int err = 0; |
189 | |
190 | /* device */ |
191 | if (sb->s_op->show_devname) { |
192 | seq_puts(m, "device "); |
193 | err = sb->s_op->show_devname(m, mnt_path.dentry); |
194 | } else { |
195 | if (r->mnt_devname) { |
196 | seq_puts(m, "device "); |
197 | mangle(m, r->mnt_devname); |
198 | } else |
199 | seq_puts(m, "no device"); |
200 | } |
201 | |
202 | /* mount point */ |
203 | seq_puts(m, " mounted on "); |
204 | seq_path(m, &mnt_path, " \t\n\\"); |
205 | seq_putc(m, ' '); |
206 | |
207 | /* file system type */ |
208 | seq_puts(m, "with fstype "); |
209 | show_type(m, sb); |
210 | |
211 | /* optional statistics */ |
212 | if (sb->s_op->show_stats) { |
213 | seq_putc(m, ' '); |
214 | if (!err) |
215 | err = sb->s_op->show_stats(m, mnt_path.dentry); |
216 | } |
217 | |
218 | seq_putc(m, '\n'); |
219 | return err; |
220 | } |
221 | |
222 | static int mounts_open_common(struct inode *inode, struct file *file, |
223 | int (*show)(struct seq_file *, struct vfsmount *)) |
224 | { |
225 | struct task_struct *task = get_proc_task(inode); |
226 | struct nsproxy *nsp; |
227 | struct mnt_namespace *ns = NULL; |
228 | struct path root; |
229 | struct proc_mounts *p; |
230 | int ret = -EINVAL; |
231 | |
232 | if (!task) |
233 | goto err; |
234 | |
235 | rcu_read_lock(); |
236 | nsp = task_nsproxy(task); |
237 | if (!nsp) { |
238 | rcu_read_unlock(); |
239 | put_task_struct(task); |
240 | goto err; |
241 | } |
242 | ns = nsp->mnt_ns; |
243 | if (!ns) { |
244 | rcu_read_unlock(); |
245 | put_task_struct(task); |
246 | goto err; |
247 | } |
248 | get_mnt_ns(ns); |
249 | rcu_read_unlock(); |
250 | task_lock(task); |
251 | if (!task->fs) { |
252 | task_unlock(task); |
253 | put_task_struct(task); |
254 | ret = -ENOENT; |
255 | goto err_put_ns; |
256 | } |
257 | get_fs_root(task->fs, &root); |
258 | task_unlock(task); |
259 | put_task_struct(task); |
260 | |
261 | ret = -ENOMEM; |
262 | p = kmalloc(sizeof(struct proc_mounts), GFP_KERNEL); |
263 | if (!p) |
264 | goto err_put_path; |
265 | |
266 | file->private_data = &p->m; |
267 | ret = seq_open(file, &mounts_op); |
268 | if (ret) |
269 | goto err_free; |
270 | |
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 = proc_mounts(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 | }; |
333 |
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