blob: 8db932da40091b44f2a8df49e921d942f2291908 [file] [log] [blame]
Al Viro0226f492011-12-06 12:21:54 -05001/*
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
18static unsigned mounts_poll(struct file *file, poll_table *wait)
19{
Al Viro6ce6e242012-06-09 01:16:59 -040020 struct proc_mounts *p = proc_mounts(file->private_data);
Al Viro0226f492011-12-06 12:21:54 -050021 struct mnt_namespace *ns = p->ns;
22 unsigned res = POLLIN | POLLRDNORM;
Al Viroaab407f2013-09-29 10:59:59 -040023 int event;
Al Viro0226f492011-12-06 12:21:54 -050024
25 poll_wait(file, &p->ns->poll, wait);
26
Al Viroaab407f2013-09-29 10:59:59 -040027 event = ACCESS_ONCE(ns->event);
28 if (p->m.poll_event != event) {
29 p->m.poll_event = event;
Al Viro0226f492011-12-06 12:21:54 -050030 res |= POLLERR | POLLPRI;
31 }
Al Viro0226f492011-12-06 12:21:54 -050032
33 return res;
34}
35
36struct proc_fs_info {
37 int flag;
38 const char *str;
39};
40
41static 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" },
Theodore Ts'o0ae45f62015-02-02 00:37:00 -050047 { MS_LAZYTIME, ",lazytime" },
Al Viro0226f492011-12-06 12:21:54 -050048 { 0, NULL }
49 };
50 const struct proc_fs_info *fs_infop;
51
52 for (fs_infop = fs_info; fs_infop->flag; fs_infop++) {
53 if (sb->s_flags & fs_infop->flag)
54 seq_puts(m, fs_infop->str);
55 }
56
57 return security_sb_show_options(m, sb);
58}
59
60static void show_mnt_opts(struct seq_file *m, struct vfsmount *mnt)
61{
62 static const struct proc_fs_info mnt_info[] = {
63 { MNT_NOSUID, ",nosuid" },
64 { MNT_NODEV, ",nodev" },
65 { MNT_NOEXEC, ",noexec" },
66 { MNT_NOATIME, ",noatime" },
67 { MNT_NODIRATIME, ",nodiratime" },
68 { MNT_RELATIME, ",relatime" },
69 { 0, NULL }
70 };
71 const struct proc_fs_info *fs_infop;
72
73 for (fs_infop = mnt_info; fs_infop->flag; fs_infop++) {
74 if (mnt->mnt_flags & fs_infop->flag)
75 seq_puts(m, fs_infop->str);
76 }
77}
78
79static inline void mangle(struct seq_file *m, const char *s)
80{
81 seq_escape(m, s, " \t\n\\");
82}
83
84static void show_type(struct seq_file *m, struct super_block *sb)
85{
86 mangle(m, sb->s_type->name);
87 if (sb->s_subtype && sb->s_subtype[0]) {
88 seq_putc(m, '.');
89 mangle(m, sb->s_subtype);
90 }
91}
92
93static int show_vfsmnt(struct seq_file *m, struct vfsmount *mnt)
94{
Dmitry V. Levin9d4d6572014-12-16 06:59:37 +030095 struct proc_mounts *p = proc_mounts(m);
Al Viro0226f492011-12-06 12:21:54 -050096 struct mount *r = real_mount(mnt);
97 int err = 0;
98 struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
Al Virod861c632011-12-08 21:32:45 -050099 struct super_block *sb = mnt_path.dentry->d_sb;
Al Viro0226f492011-12-06 12:21:54 -0500100
Al Virod861c632011-12-08 21:32:45 -0500101 if (sb->s_op->show_devname) {
102 err = sb->s_op->show_devname(m, mnt_path.dentry);
Al Viro0226f492011-12-06 12:21:54 -0500103 if (err)
104 goto out;
105 } else {
106 mangle(m, r->mnt_devname ? r->mnt_devname : "none");
107 }
108 seq_putc(m, ' ');
Dmitry V. Levin9d4d6572014-12-16 06:59:37 +0300109 /* mountpoints outside of chroot jail will give SEQ_SKIP on this */
110 err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
111 if (err)
112 goto out;
Al Viro0226f492011-12-06 12:21:54 -0500113 seq_putc(m, ' ');
Al Virod861c632011-12-08 21:32:45 -0500114 show_type(m, sb);
Al Viro0226f492011-12-06 12:21:54 -0500115 seq_puts(m, __mnt_is_readonly(mnt) ? " ro" : " rw");
Al Virod861c632011-12-08 21:32:45 -0500116 err = show_sb_opts(m, sb);
Al Viro0226f492011-12-06 12:21:54 -0500117 if (err)
118 goto out;
119 show_mnt_opts(m, mnt);
Al Virod861c632011-12-08 21:32:45 -0500120 if (sb->s_op->show_options)
Al Viro34c80b12011-12-08 21:32:45 -0500121 err = sb->s_op->show_options(m, mnt_path.dentry);
Al Viro0226f492011-12-06 12:21:54 -0500122 seq_puts(m, " 0 0\n");
123out:
124 return err;
125}
126
127static int show_mountinfo(struct seq_file *m, struct vfsmount *mnt)
128{
Al Viro6ce6e242012-06-09 01:16:59 -0400129 struct proc_mounts *p = proc_mounts(m);
Al Viro0226f492011-12-06 12:21:54 -0500130 struct mount *r = real_mount(mnt);
131 struct super_block *sb = mnt->mnt_sb;
132 struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
Al Viro0226f492011-12-06 12:21:54 -0500133 int err = 0;
134
135 seq_printf(m, "%i %i %u:%u ", r->mnt_id, r->mnt_parent->mnt_id,
136 MAJOR(sb->s_dev), MINOR(sb->s_dev));
137 if (sb->s_op->show_path)
Al Viroa6322de2011-12-08 21:37:57 -0500138 err = sb->s_op->show_path(m, mnt->mnt_root);
Al Viro0226f492011-12-06 12:21:54 -0500139 else
140 seq_dentry(m, mnt->mnt_root, " \t\n\\");
141 if (err)
142 goto out;
143 seq_putc(m, ' ');
144
145 /* mountpoints outside of chroot jail will give SEQ_SKIP on this */
Dmitry V. Levin9ad4dc42012-10-17 20:29:36 +0400146 err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
Al Viro0226f492011-12-06 12:21:54 -0500147 if (err)
148 goto out;
149
150 seq_puts(m, mnt->mnt_flags & MNT_READONLY ? " ro" : " rw");
151 show_mnt_opts(m, mnt);
152
153 /* Tagged fields ("foo:X" or "bar") */
154 if (IS_MNT_SHARED(r))
155 seq_printf(m, " shared:%i", r->mnt_group_id);
156 if (IS_MNT_SLAVE(r)) {
157 int master = r->mnt_master->mnt_group_id;
158 int dom = get_dominating_id(r, &p->root);
159 seq_printf(m, " master:%i", master);
160 if (dom && dom != master)
161 seq_printf(m, " propagate_from:%i", dom);
162 }
163 if (IS_MNT_UNBINDABLE(r))
164 seq_puts(m, " unbindable");
165
166 /* Filesystem specific data */
167 seq_puts(m, " - ");
168 show_type(m, sb);
169 seq_putc(m, ' ');
170 if (sb->s_op->show_devname)
Al Virod861c632011-12-08 21:32:45 -0500171 err = sb->s_op->show_devname(m, mnt->mnt_root);
Al Viro0226f492011-12-06 12:21:54 -0500172 else
173 mangle(m, r->mnt_devname ? r->mnt_devname : "none");
174 if (err)
175 goto out;
176 seq_puts(m, sb->s_flags & MS_RDONLY ? " ro" : " rw");
177 err = show_sb_opts(m, sb);
178 if (err)
179 goto out;
180 if (sb->s_op->show_options)
Al Viro34c80b12011-12-08 21:32:45 -0500181 err = sb->s_op->show_options(m, mnt->mnt_root);
Al Viro0226f492011-12-06 12:21:54 -0500182 seq_putc(m, '\n');
183out:
184 return err;
185}
186
187static int show_vfsstat(struct seq_file *m, struct vfsmount *mnt)
188{
Dmitry V. Levin9d4d6572014-12-16 06:59:37 +0300189 struct proc_mounts *p = proc_mounts(m);
Al Viro0226f492011-12-06 12:21:54 -0500190 struct mount *r = real_mount(mnt);
191 struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
Al Viro64132372011-12-08 20:51:13 -0500192 struct super_block *sb = mnt_path.dentry->d_sb;
Al Viro0226f492011-12-06 12:21:54 -0500193 int err = 0;
194
195 /* device */
Al Viro64132372011-12-08 20:51:13 -0500196 if (sb->s_op->show_devname) {
Al Viro0226f492011-12-06 12:21:54 -0500197 seq_puts(m, "device ");
Al Virod861c632011-12-08 21:32:45 -0500198 err = sb->s_op->show_devname(m, mnt_path.dentry);
Al Viro0226f492011-12-06 12:21:54 -0500199 } else {
200 if (r->mnt_devname) {
201 seq_puts(m, "device ");
202 mangle(m, r->mnt_devname);
203 } else
204 seq_puts(m, "no device");
205 }
206
207 /* mount point */
208 seq_puts(m, " mounted on ");
Dmitry V. Levin9d4d6572014-12-16 06:59:37 +0300209 /* mountpoints outside of chroot jail will give SEQ_SKIP on this */
210 err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
211 if (err)
212 goto out;
Al Viro0226f492011-12-06 12:21:54 -0500213 seq_putc(m, ' ');
214
215 /* file system type */
216 seq_puts(m, "with fstype ");
Al Viro64132372011-12-08 20:51:13 -0500217 show_type(m, sb);
Al Viro0226f492011-12-06 12:21:54 -0500218
219 /* optional statistics */
Al Viro64132372011-12-08 20:51:13 -0500220 if (sb->s_op->show_stats) {
Al Viro0226f492011-12-06 12:21:54 -0500221 seq_putc(m, ' ');
222 if (!err)
Al Viro64132372011-12-08 20:51:13 -0500223 err = sb->s_op->show_stats(m, mnt_path.dentry);
Al Viro0226f492011-12-06 12:21:54 -0500224 }
225
226 seq_putc(m, '\n');
Dmitry V. Levin9d4d6572014-12-16 06:59:37 +0300227out:
Al Viro0226f492011-12-06 12:21:54 -0500228 return err;
229}
230
231static int mounts_open_common(struct inode *inode, struct file *file,
232 int (*show)(struct seq_file *, struct vfsmount *))
233{
234 struct task_struct *task = get_proc_task(inode);
235 struct nsproxy *nsp;
236 struct mnt_namespace *ns = NULL;
237 struct path root;
238 struct proc_mounts *p;
239 int ret = -EINVAL;
240
241 if (!task)
242 goto err;
243
Eric W. Biederman728dba32014-02-03 19:13:49 -0800244 task_lock(task);
245 nsp = task->nsproxy;
Axel Lin3d931162014-01-23 15:55:44 -0800246 if (!nsp || !nsp->mnt_ns) {
Eric W. Biederman728dba32014-02-03 19:13:49 -0800247 task_unlock(task);
Al Viro0226f492011-12-06 12:21:54 -0500248 put_task_struct(task);
249 goto err;
250 }
251 ns = nsp->mnt_ns;
Al Viro0226f492011-12-06 12:21:54 -0500252 get_mnt_ns(ns);
Al Viro0226f492011-12-06 12:21:54 -0500253 if (!task->fs) {
254 task_unlock(task);
255 put_task_struct(task);
256 ret = -ENOENT;
257 goto err_put_ns;
258 }
259 get_fs_root(task->fs, &root);
260 task_unlock(task);
261 put_task_struct(task);
262
263 ret = -ENOMEM;
264 p = kmalloc(sizeof(struct proc_mounts), GFP_KERNEL);
265 if (!p)
266 goto err_put_path;
267
268 file->private_data = &p->m;
269 ret = seq_open(file, &mounts_op);
270 if (ret)
271 goto err_free;
272
Al Viro0226f492011-12-06 12:21:54 -0500273 p->ns = ns;
274 p->root = root;
275 p->m.poll_event = ns->event;
276 p->show = show;
Al Viroc7999c32014-02-27 14:40:10 -0500277 p->cached_event = ~0ULL;
Al Viro0226f492011-12-06 12:21:54 -0500278
279 return 0;
280
281 err_free:
282 kfree(p);
283 err_put_path:
284 path_put(&root);
285 err_put_ns:
286 put_mnt_ns(ns);
287 err:
288 return ret;
289}
290
291static int mounts_release(struct inode *inode, struct file *file)
292{
Al Viro6ce6e242012-06-09 01:16:59 -0400293 struct proc_mounts *p = proc_mounts(file->private_data);
Al Viro0226f492011-12-06 12:21:54 -0500294 path_put(&p->root);
295 put_mnt_ns(p->ns);
296 return seq_release(inode, file);
297}
298
299static int mounts_open(struct inode *inode, struct file *file)
300{
301 return mounts_open_common(inode, file, show_vfsmnt);
302}
303
304static int mountinfo_open(struct inode *inode, struct file *file)
305{
306 return mounts_open_common(inode, file, show_mountinfo);
307}
308
309static int mountstats_open(struct inode *inode, struct file *file)
310{
311 return mounts_open_common(inode, file, show_vfsstat);
312}
313
314const struct file_operations proc_mounts_operations = {
315 .open = mounts_open,
316 .read = seq_read,
317 .llseek = seq_lseek,
318 .release = mounts_release,
319 .poll = mounts_poll,
320};
321
322const struct file_operations proc_mountinfo_operations = {
323 .open = mountinfo_open,
324 .read = seq_read,
325 .llseek = seq_lseek,
326 .release = mounts_release,
327 .poll = mounts_poll,
328};
329
330const struct file_operations proc_mountstats_operations = {
331 .open = mountstats_open,
332 .read = seq_read,
333 .llseek = seq_lseek,
334 .release = mounts_release,
335};