blob: 1a81373947f33ec4e56b5e34e24814b4c267800a [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" },
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
59static 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
78static inline void mangle(struct seq_file *m, const char *s)
79{
80 seq_escape(m, s, " \t\n\\");
81}
82
83static 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
92static 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 };
Al Virod861c632011-12-08 21:32:45 -050097 struct super_block *sb = mnt_path.dentry->d_sb;
Al Viro0226f492011-12-06 12:21:54 -050098
Al Virod861c632011-12-08 21:32:45 -050099 if (sb->s_op->show_devname) {
100 err = sb->s_op->show_devname(m, mnt_path.dentry);
Al Viro0226f492011-12-06 12:21:54 -0500101 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, ' ');
Al Virod861c632011-12-08 21:32:45 -0500109 show_type(m, sb);
Al Viro0226f492011-12-06 12:21:54 -0500110 seq_puts(m, __mnt_is_readonly(mnt) ? " ro" : " rw");
Al Virod861c632011-12-08 21:32:45 -0500111 err = show_sb_opts(m, sb);
Al Viro0226f492011-12-06 12:21:54 -0500112 if (err)
113 goto out;
114 show_mnt_opts(m, mnt);
Al Virod861c632011-12-08 21:32:45 -0500115 if (sb->s_op->show_options)
Al Viro34c80b12011-12-08 21:32:45 -0500116 err = sb->s_op->show_options(m, mnt_path.dentry);
Al Viro0226f492011-12-06 12:21:54 -0500117 seq_puts(m, " 0 0\n");
118out:
119 return err;
120}
121
122static int show_mountinfo(struct seq_file *m, struct vfsmount *mnt)
123{
Al Viro6ce6e242012-06-09 01:16:59 -0400124 struct proc_mounts *p = proc_mounts(m);
Al Viro0226f492011-12-06 12:21:54 -0500125 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)
Al Viroa6322de2011-12-08 21:37:57 -0500134 err = sb->s_op->show_path(m, mnt->mnt_root);
Al Viro0226f492011-12-06 12:21:54 -0500135 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)
Al Virod861c632011-12-08 21:32:45 -0500167 err = sb->s_op->show_devname(m, mnt->mnt_root);
Al Viro0226f492011-12-06 12:21:54 -0500168 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)
Al Viro34c80b12011-12-08 21:32:45 -0500177 err = sb->s_op->show_options(m, mnt->mnt_root);
Al Viro0226f492011-12-06 12:21:54 -0500178 seq_putc(m, '\n');
179out:
180 return err;
181}
182
183static 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 };
Al Viro64132372011-12-08 20:51:13 -0500187 struct super_block *sb = mnt_path.dentry->d_sb;
Al Viro0226f492011-12-06 12:21:54 -0500188 int err = 0;
189
190 /* device */
Al Viro64132372011-12-08 20:51:13 -0500191 if (sb->s_op->show_devname) {
Al Viro0226f492011-12-06 12:21:54 -0500192 seq_puts(m, "device ");
Al Virod861c632011-12-08 21:32:45 -0500193 err = sb->s_op->show_devname(m, mnt_path.dentry);
Al Viro0226f492011-12-06 12:21:54 -0500194 } 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 ");
Al Viro64132372011-12-08 20:51:13 -0500209 show_type(m, sb);
Al Viro0226f492011-12-06 12:21:54 -0500210
211 /* optional statistics */
Al Viro64132372011-12-08 20:51:13 -0500212 if (sb->s_op->show_stats) {
Al Viro0226f492011-12-06 12:21:54 -0500213 seq_putc(m, ' ');
214 if (!err)
Al Viro64132372011-12-08 20:51:13 -0500215 err = sb->s_op->show_stats(m, mnt_path.dentry);
Al Viro0226f492011-12-06 12:21:54 -0500216 }
217
218 seq_putc(m, '\n');
219 return err;
220}
221
222static 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);
Axel Lin3d931162014-01-23 15:55:44 -0800237 if (!nsp || !nsp->mnt_ns) {
Al Viro0226f492011-12-06 12:21:54 -0500238 rcu_read_unlock();
239 put_task_struct(task);
240 goto err;
241 }
242 ns = nsp->mnt_ns;
Al Viro0226f492011-12-06 12:21:54 -0500243 get_mnt_ns(ns);
244 rcu_read_unlock();
245 task_lock(task);
246 if (!task->fs) {
247 task_unlock(task);
248 put_task_struct(task);
249 ret = -ENOENT;
250 goto err_put_ns;
251 }
252 get_fs_root(task->fs, &root);
253 task_unlock(task);
254 put_task_struct(task);
255
256 ret = -ENOMEM;
257 p = kmalloc(sizeof(struct proc_mounts), GFP_KERNEL);
258 if (!p)
259 goto err_put_path;
260
261 file->private_data = &p->m;
262 ret = seq_open(file, &mounts_op);
263 if (ret)
264 goto err_free;
265
Al Viro0226f492011-12-06 12:21:54 -0500266 p->ns = ns;
267 p->root = root;
268 p->m.poll_event = ns->event;
269 p->show = show;
Al Viroc7999c32014-02-27 14:40:10 -0500270 p->cached_event = ~0ULL;
Al Viro0226f492011-12-06 12:21:54 -0500271
272 return 0;
273
274 err_free:
275 kfree(p);
276 err_put_path:
277 path_put(&root);
278 err_put_ns:
279 put_mnt_ns(ns);
280 err:
281 return ret;
282}
283
284static int mounts_release(struct inode *inode, struct file *file)
285{
Al Viro6ce6e242012-06-09 01:16:59 -0400286 struct proc_mounts *p = proc_mounts(file->private_data);
Al Viro0226f492011-12-06 12:21:54 -0500287 path_put(&p->root);
288 put_mnt_ns(p->ns);
289 return seq_release(inode, file);
290}
291
292static int mounts_open(struct inode *inode, struct file *file)
293{
294 return mounts_open_common(inode, file, show_vfsmnt);
295}
296
297static int mountinfo_open(struct inode *inode, struct file *file)
298{
299 return mounts_open_common(inode, file, show_mountinfo);
300}
301
302static int mountstats_open(struct inode *inode, struct file *file)
303{
304 return mounts_open_common(inode, file, show_vfsstat);
305}
306
307const struct file_operations proc_mounts_operations = {
308 .open = mounts_open,
309 .read = seq_read,
310 .llseek = seq_lseek,
311 .release = mounts_release,
312 .poll = mounts_poll,
313};
314
315const struct file_operations proc_mountinfo_operations = {
316 .open = mountinfo_open,
317 .read = seq_read,
318 .llseek = seq_lseek,
319 .release = mounts_release,
320 .poll = mounts_poll,
321};
322
323const struct file_operations proc_mountstats_operations = {
324 .open = mountstats_open,
325 .read = seq_read,
326 .llseek = seq_lseek,
327 .release = mounts_release,
328};