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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>
Ingo Molnarf719ff92017-02-06 10:57:33 +010013#include <linux/sched/task.h>
14
Al Viro0226f492011-12-06 12:21:54 -050015#include "proc/internal.h" /* only for get_proc_task() in ->open() */
16
17#include "pnode.h"
18#include "internal.h"
19
20static unsigned mounts_poll(struct file *file, poll_table *wait)
21{
Yann Droneaudede1bf02015-06-30 14:57:30 -070022 struct seq_file *m = file->private_data;
23 struct proc_mounts *p = m->private;
Al Viro0226f492011-12-06 12:21:54 -050024 struct mnt_namespace *ns = p->ns;
25 unsigned res = POLLIN | POLLRDNORM;
Al Viroaab407f2013-09-29 10:59:59 -040026 int event;
Al Viro0226f492011-12-06 12:21:54 -050027
28 poll_wait(file, &p->ns->poll, wait);
29
Al Viroaab407f2013-09-29 10:59:59 -040030 event = ACCESS_ONCE(ns->event);
Yann Droneaudede1bf02015-06-30 14:57:30 -070031 if (m->poll_event != event) {
32 m->poll_event = event;
Al Viro0226f492011-12-06 12:21:54 -050033 res |= POLLERR | POLLPRI;
34 }
Al Viro0226f492011-12-06 12:21:54 -050035
36 return res;
37}
38
39struct proc_fs_info {
40 int flag;
41 const char *str;
42};
43
44static 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" },
Theodore Ts'o0ae45f62015-02-02 00:37:00 -050050 { MS_LAZYTIME, ",lazytime" },
Al Viro0226f492011-12-06 12:21:54 -050051 { 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
63static 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
82static inline void mangle(struct seq_file *m, const char *s)
83{
84 seq_escape(m, s, " \t\n\\");
85}
86
87static 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
96static int show_vfsmnt(struct seq_file *m, struct vfsmount *mnt)
97{
Yann Droneaudede1bf02015-06-30 14:57:30 -070098 struct proc_mounts *p = m->private;
Al Viro0226f492011-12-06 12:21:54 -050099 struct mount *r = real_mount(mnt);
Al Viro0226f492011-12-06 12:21:54 -0500100 struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
Al Virod861c632011-12-08 21:32:45 -0500101 struct super_block *sb = mnt_path.dentry->d_sb;
Dmitry V. Levin5d9f3c72015-11-19 00:57:52 +0300102 int err;
Al Viro0226f492011-12-06 12:21:54 -0500103
Al Virod861c632011-12-08 21:32:45 -0500104 if (sb->s_op->show_devname) {
105 err = sb->s_op->show_devname(m, mnt_path.dentry);
Al Viro0226f492011-12-06 12:21:54 -0500106 if (err)
107 goto out;
108 } else {
109 mangle(m, r->mnt_devname ? r->mnt_devname : "none");
110 }
111 seq_putc(m, ' ');
Dmitry V. Levin9d4d6572014-12-16 06:59:37 +0300112 /* 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;
Al Viro0226f492011-12-06 12:21:54 -0500116 seq_putc(m, ' ');
Al Virod861c632011-12-08 21:32:45 -0500117 show_type(m, sb);
Al Viro0226f492011-12-06 12:21:54 -0500118 seq_puts(m, __mnt_is_readonly(mnt) ? " ro" : " rw");
Al Virod861c632011-12-08 21:32:45 -0500119 err = show_sb_opts(m, sb);
Al Viro0226f492011-12-06 12:21:54 -0500120 if (err)
121 goto out;
122 show_mnt_opts(m, mnt);
Al Virod861c632011-12-08 21:32:45 -0500123 if (sb->s_op->show_options)
Al Viro34c80b12011-12-08 21:32:45 -0500124 err = sb->s_op->show_options(m, mnt_path.dentry);
Al Viro0226f492011-12-06 12:21:54 -0500125 seq_puts(m, " 0 0\n");
126out:
127 return err;
128}
129
130static int show_mountinfo(struct seq_file *m, struct vfsmount *mnt)
131{
Yann Droneaudede1bf02015-06-30 14:57:30 -0700132 struct proc_mounts *p = m->private;
Al Viro0226f492011-12-06 12:21:54 -0500133 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 };
Dmitry V. Levin6ce4bca2015-11-19 00:58:20 +0300136 int err;
Al Viro0226f492011-12-06 12:21:54 -0500137
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));
Dmitry V. Levin6ce4bca2015-11-19 00:58:20 +0300140 if (sb->s_op->show_path) {
Al Viroa6322de2011-12-08 21:37:57 -0500141 err = sb->s_op->show_path(m, mnt->mnt_root);
Dmitry V. Levin6ce4bca2015-11-19 00:58:20 +0300142 if (err)
143 goto out;
144 } else {
Al Viro0226f492011-12-06 12:21:54 -0500145 seq_dentry(m, mnt->mnt_root, " \t\n\\");
Dmitry V. Levin6ce4bca2015-11-19 00:58:20 +0300146 }
Al Viro0226f492011-12-06 12:21:54 -0500147 seq_putc(m, ' ');
148
149 /* mountpoints outside of chroot jail will give SEQ_SKIP on this */
Dmitry V. Levin9ad4dc42012-10-17 20:29:36 +0400150 err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
Al Viro0226f492011-12-06 12:21:54 -0500151 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, ' ');
Dmitry V. Levin6ce4bca2015-11-19 00:58:20 +0300174 if (sb->s_op->show_devname) {
Al Virod861c632011-12-08 21:32:45 -0500175 err = sb->s_op->show_devname(m, mnt->mnt_root);
Dmitry V. Levin6ce4bca2015-11-19 00:58:20 +0300176 if (err)
177 goto out;
178 } else {
Al Viro0226f492011-12-06 12:21:54 -0500179 mangle(m, r->mnt_devname ? r->mnt_devname : "none");
Dmitry V. Levin6ce4bca2015-11-19 00:58:20 +0300180 }
Al Viro0226f492011-12-06 12:21:54 -0500181 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_options)
Al Viro34c80b12011-12-08 21:32:45 -0500186 err = sb->s_op->show_options(m, mnt->mnt_root);
Al Viro0226f492011-12-06 12:21:54 -0500187 seq_putc(m, '\n');
188out:
189 return err;
190}
191
192static int show_vfsstat(struct seq_file *m, struct vfsmount *mnt)
193{
Yann Droneaudede1bf02015-06-30 14:57:30 -0700194 struct proc_mounts *p = m->private;
Al Viro0226f492011-12-06 12:21:54 -0500195 struct mount *r = real_mount(mnt);
196 struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
Al Viro64132372011-12-08 20:51:13 -0500197 struct super_block *sb = mnt_path.dentry->d_sb;
Dmitry V. Levinb896fb32015-11-19 00:58:32 +0300198 int err;
Al Viro0226f492011-12-06 12:21:54 -0500199
200 /* device */
Al Viro64132372011-12-08 20:51:13 -0500201 if (sb->s_op->show_devname) {
Al Viro0226f492011-12-06 12:21:54 -0500202 seq_puts(m, "device ");
Al Virod861c632011-12-08 21:32:45 -0500203 err = sb->s_op->show_devname(m, mnt_path.dentry);
Dmitry V. Levin5f8d4982015-03-19 11:10:54 +0000204 if (err)
205 goto out;
Al Viro0226f492011-12-06 12:21:54 -0500206 } 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 ");
Dmitry V. Levin9d4d6572014-12-16 06:59:37 +0300216 /* 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;
Al Viro0226f492011-12-06 12:21:54 -0500220 seq_putc(m, ' ');
221
222 /* file system type */
223 seq_puts(m, "with fstype ");
Al Viro64132372011-12-08 20:51:13 -0500224 show_type(m, sb);
Al Viro0226f492011-12-06 12:21:54 -0500225
226 /* optional statistics */
Al Viro64132372011-12-08 20:51:13 -0500227 if (sb->s_op->show_stats) {
Al Viro0226f492011-12-06 12:21:54 -0500228 seq_putc(m, ' ');
Dmitry V. Levinb896fb32015-11-19 00:58:32 +0300229 err = sb->s_op->show_stats(m, mnt_path.dentry);
Al Viro0226f492011-12-06 12:21:54 -0500230 }
231
232 seq_putc(m, '\n');
Dmitry V. Levin9d4d6572014-12-16 06:59:37 +0300233out:
Al Viro0226f492011-12-06 12:21:54 -0500234 return err;
235}
236
237static 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;
Yann Droneaudede1bf02015-06-30 14:57:30 -0700245 struct seq_file *m;
Al Viro0226f492011-12-06 12:21:54 -0500246 int ret = -EINVAL;
247
248 if (!task)
249 goto err;
250
Eric W. Biederman728dba32014-02-03 19:13:49 -0800251 task_lock(task);
252 nsp = task->nsproxy;
Axel Lin3d931162014-01-23 15:55:44 -0800253 if (!nsp || !nsp->mnt_ns) {
Eric W. Biederman728dba32014-02-03 19:13:49 -0800254 task_unlock(task);
Al Viro0226f492011-12-06 12:21:54 -0500255 put_task_struct(task);
256 goto err;
257 }
258 ns = nsp->mnt_ns;
Al Viro0226f492011-12-06 12:21:54 -0500259 get_mnt_ns(ns);
Al Viro0226f492011-12-06 12:21:54 -0500260 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
Yann Droneaudede1bf02015-06-30 14:57:30 -0700270 ret = seq_open_private(file, &mounts_op, sizeof(struct proc_mounts));
271 if (ret)
Al Viro0226f492011-12-06 12:21:54 -0500272 goto err_put_path;
273
Yann Droneaudede1bf02015-06-30 14:57:30 -0700274 m = file->private_data;
275 m->poll_event = ns->event;
Al Viro0226f492011-12-06 12:21:54 -0500276
Yann Droneaudede1bf02015-06-30 14:57:30 -0700277 p = m->private;
Al Viro0226f492011-12-06 12:21:54 -0500278 p->ns = ns;
279 p->root = root;
Al Viro0226f492011-12-06 12:21:54 -0500280 p->show = show;
Al Viroc7999c32014-02-27 14:40:10 -0500281 p->cached_event = ~0ULL;
Al Viro0226f492011-12-06 12:21:54 -0500282
283 return 0;
284
Al Viro0226f492011-12-06 12:21:54 -0500285 err_put_path:
286 path_put(&root);
287 err_put_ns:
288 put_mnt_ns(ns);
289 err:
290 return ret;
291}
292
293static int mounts_release(struct inode *inode, struct file *file)
294{
Yann Droneaudede1bf02015-06-30 14:57:30 -0700295 struct seq_file *m = file->private_data;
296 struct proc_mounts *p = m->private;
Al Viro0226f492011-12-06 12:21:54 -0500297 path_put(&p->root);
298 put_mnt_ns(p->ns);
Yann Droneaudede1bf02015-06-30 14:57:30 -0700299 return seq_release_private(inode, file);
Al Viro0226f492011-12-06 12:21:54 -0500300}
301
302static int mounts_open(struct inode *inode, struct file *file)
303{
304 return mounts_open_common(inode, file, show_vfsmnt);
305}
306
307static int mountinfo_open(struct inode *inode, struct file *file)
308{
309 return mounts_open_common(inode, file, show_mountinfo);
310}
311
312static int mountstats_open(struct inode *inode, struct file *file)
313{
314 return mounts_open_common(inode, file, show_vfsstat);
315}
316
317const 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
325const 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
333const struct file_operations proc_mountstats_operations = {
334 .open = mountstats_open,
335 .read = seq_read,
336 .llseek = seq_lseek,
337 .release = mounts_release,
338};