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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>
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{
Yann Droneaudede1bf02015-06-30 14:57:30 -070020 struct seq_file *m = file->private_data;
21 struct proc_mounts *p = m->private;
Al Viro0226f492011-12-06 12:21:54 -050022 struct mnt_namespace *ns = p->ns;
23 unsigned res = POLLIN | POLLRDNORM;
Al Viroaab407f2013-09-29 10:59:59 -040024 int event;
Al Viro0226f492011-12-06 12:21:54 -050025
26 poll_wait(file, &p->ns->poll, wait);
27
Al Viroaab407f2013-09-29 10:59:59 -040028 event = ACCESS_ONCE(ns->event);
Yann Droneaudede1bf02015-06-30 14:57:30 -070029 if (m->poll_event != event) {
30 m->poll_event = event;
Al Viro0226f492011-12-06 12:21:54 -050031 res |= POLLERR | POLLPRI;
32 }
Al Viro0226f492011-12-06 12:21:54 -050033
34 return res;
35}
36
37struct proc_fs_info {
38 int flag;
39 const char *str;
40};
41
42static int show_sb_opts(struct seq_file *m, struct super_block *sb)
43{
44 static const struct proc_fs_info fs_info[] = {
45 { MS_SYNCHRONOUS, ",sync" },
46 { MS_DIRSYNC, ",dirsync" },
47 { MS_MANDLOCK, ",mand" },
Theodore Ts'o0ae45f62015-02-02 00:37:00 -050048 { MS_LAZYTIME, ",lazytime" },
Al Viro0226f492011-12-06 12:21:54 -050049 { 0, NULL }
50 };
51 const struct proc_fs_info *fs_infop;
52
53 for (fs_infop = fs_info; fs_infop->flag; fs_infop++) {
54 if (sb->s_flags & fs_infop->flag)
55 seq_puts(m, fs_infop->str);
56 }
57
58 return security_sb_show_options(m, sb);
59}
60
61static void show_mnt_opts(struct seq_file *m, struct vfsmount *mnt)
62{
63 static const struct proc_fs_info mnt_info[] = {
64 { MNT_NOSUID, ",nosuid" },
65 { MNT_NODEV, ",nodev" },
66 { MNT_NOEXEC, ",noexec" },
67 { MNT_NOATIME, ",noatime" },
68 { MNT_NODIRATIME, ",nodiratime" },
69 { MNT_RELATIME, ",relatime" },
70 { 0, NULL }
71 };
72 const struct proc_fs_info *fs_infop;
73
74 for (fs_infop = mnt_info; fs_infop->flag; fs_infop++) {
75 if (mnt->mnt_flags & fs_infop->flag)
76 seq_puts(m, fs_infop->str);
77 }
78}
79
80static inline void mangle(struct seq_file *m, const char *s)
81{
82 seq_escape(m, s, " \t\n\\");
83}
84
85static void show_type(struct seq_file *m, struct super_block *sb)
86{
87 mangle(m, sb->s_type->name);
88 if (sb->s_subtype && sb->s_subtype[0]) {
89 seq_putc(m, '.');
90 mangle(m, sb->s_subtype);
91 }
92}
93
94static int show_vfsmnt(struct seq_file *m, struct vfsmount *mnt)
95{
Yann Droneaudede1bf02015-06-30 14:57:30 -070096 struct proc_mounts *p = m->private;
Al Viro0226f492011-12-06 12:21:54 -050097 struct mount *r = real_mount(mnt);
98 int err = 0;
99 struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
Al Virod861c632011-12-08 21:32:45 -0500100 struct super_block *sb = mnt_path.dentry->d_sb;
Al Viro0226f492011-12-06 12:21:54 -0500101
Al Virod861c632011-12-08 21:32:45 -0500102 if (sb->s_op->show_devname) {
103 err = sb->s_op->show_devname(m, mnt_path.dentry);
Al Viro0226f492011-12-06 12:21:54 -0500104 if (err)
105 goto out;
106 } else {
107 mangle(m, r->mnt_devname ? r->mnt_devname : "none");
108 }
109 seq_putc(m, ' ');
Dmitry V. Levin9d4d6572014-12-16 06:59:37 +0300110 /* mountpoints outside of chroot jail will give SEQ_SKIP on this */
111 err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
112 if (err)
113 goto out;
Al Viro0226f492011-12-06 12:21:54 -0500114 seq_putc(m, ' ');
Al Virod861c632011-12-08 21:32:45 -0500115 show_type(m, sb);
Al Viro0226f492011-12-06 12:21:54 -0500116 seq_puts(m, __mnt_is_readonly(mnt) ? " ro" : " rw");
Al Virod861c632011-12-08 21:32:45 -0500117 err = show_sb_opts(m, sb);
Al Viro0226f492011-12-06 12:21:54 -0500118 if (err)
119 goto out;
120 show_mnt_opts(m, mnt);
Al Virod861c632011-12-08 21:32:45 -0500121 if (sb->s_op->show_options)
Al Viro34c80b12011-12-08 21:32:45 -0500122 err = sb->s_op->show_options(m, mnt_path.dentry);
Al Viro0226f492011-12-06 12:21:54 -0500123 seq_puts(m, " 0 0\n");
124out:
125 return err;
126}
127
128static int show_mountinfo(struct seq_file *m, struct vfsmount *mnt)
129{
Yann Droneaudede1bf02015-06-30 14:57:30 -0700130 struct proc_mounts *p = m->private;
Al Viro0226f492011-12-06 12:21:54 -0500131 struct mount *r = real_mount(mnt);
132 struct super_block *sb = mnt->mnt_sb;
133 struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
Al Viro0226f492011-12-06 12:21:54 -0500134 int err = 0;
135
136 seq_printf(m, "%i %i %u:%u ", r->mnt_id, r->mnt_parent->mnt_id,
137 MAJOR(sb->s_dev), MINOR(sb->s_dev));
138 if (sb->s_op->show_path)
Al Viroa6322de2011-12-08 21:37:57 -0500139 err = sb->s_op->show_path(m, mnt->mnt_root);
Al Viro0226f492011-12-06 12:21:54 -0500140 else
141 seq_dentry(m, mnt->mnt_root, " \t\n\\");
142 if (err)
143 goto out;
144 seq_putc(m, ' ');
145
146 /* mountpoints outside of chroot jail will give SEQ_SKIP on this */
Dmitry V. Levin9ad4dc42012-10-17 20:29:36 +0400147 err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
Al Viro0226f492011-12-06 12:21:54 -0500148 if (err)
149 goto out;
150
151 seq_puts(m, mnt->mnt_flags & MNT_READONLY ? " ro" : " rw");
152 show_mnt_opts(m, mnt);
153
154 /* Tagged fields ("foo:X" or "bar") */
155 if (IS_MNT_SHARED(r))
156 seq_printf(m, " shared:%i", r->mnt_group_id);
157 if (IS_MNT_SLAVE(r)) {
158 int master = r->mnt_master->mnt_group_id;
159 int dom = get_dominating_id(r, &p->root);
160 seq_printf(m, " master:%i", master);
161 if (dom && dom != master)
162 seq_printf(m, " propagate_from:%i", dom);
163 }
164 if (IS_MNT_UNBINDABLE(r))
165 seq_puts(m, " unbindable");
166
167 /* Filesystem specific data */
168 seq_puts(m, " - ");
169 show_type(m, sb);
170 seq_putc(m, ' ');
171 if (sb->s_op->show_devname)
Al Virod861c632011-12-08 21:32:45 -0500172 err = sb->s_op->show_devname(m, mnt->mnt_root);
Al Viro0226f492011-12-06 12:21:54 -0500173 else
174 mangle(m, r->mnt_devname ? r->mnt_devname : "none");
175 if (err)
176 goto out;
177 seq_puts(m, sb->s_flags & MS_RDONLY ? " ro" : " rw");
178 err = show_sb_opts(m, sb);
179 if (err)
180 goto out;
181 if (sb->s_op->show_options)
Al Viro34c80b12011-12-08 21:32:45 -0500182 err = sb->s_op->show_options(m, mnt->mnt_root);
Al Viro0226f492011-12-06 12:21:54 -0500183 seq_putc(m, '\n');
184out:
185 return err;
186}
187
188static int show_vfsstat(struct seq_file *m, struct vfsmount *mnt)
189{
Yann Droneaudede1bf02015-06-30 14:57:30 -0700190 struct proc_mounts *p = m->private;
Al Viro0226f492011-12-06 12:21:54 -0500191 struct mount *r = real_mount(mnt);
192 struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
Al Viro64132372011-12-08 20:51:13 -0500193 struct super_block *sb = mnt_path.dentry->d_sb;
Al Viro0226f492011-12-06 12:21:54 -0500194 int err = 0;
195
196 /* device */
Al Viro64132372011-12-08 20:51:13 -0500197 if (sb->s_op->show_devname) {
Al Viro0226f492011-12-06 12:21:54 -0500198 seq_puts(m, "device ");
Al Virod861c632011-12-08 21:32:45 -0500199 err = sb->s_op->show_devname(m, mnt_path.dentry);
Al Viro0226f492011-12-06 12:21:54 -0500200 } else {
201 if (r->mnt_devname) {
202 seq_puts(m, "device ");
203 mangle(m, r->mnt_devname);
204 } else
205 seq_puts(m, "no device");
206 }
207
208 /* mount point */
209 seq_puts(m, " mounted on ");
Dmitry V. Levin9d4d6572014-12-16 06:59:37 +0300210 /* mountpoints outside of chroot jail will give SEQ_SKIP on this */
211 err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
212 if (err)
213 goto out;
Al Viro0226f492011-12-06 12:21:54 -0500214 seq_putc(m, ' ');
215
216 /* file system type */
217 seq_puts(m, "with fstype ");
Al Viro64132372011-12-08 20:51:13 -0500218 show_type(m, sb);
Al Viro0226f492011-12-06 12:21:54 -0500219
220 /* optional statistics */
Al Viro64132372011-12-08 20:51:13 -0500221 if (sb->s_op->show_stats) {
Al Viro0226f492011-12-06 12:21:54 -0500222 seq_putc(m, ' ');
223 if (!err)
Al Viro64132372011-12-08 20:51:13 -0500224 err = sb->s_op->show_stats(m, mnt_path.dentry);
Al Viro0226f492011-12-06 12:21:54 -0500225 }
226
227 seq_putc(m, '\n');
Dmitry V. Levin9d4d6572014-12-16 06:59:37 +0300228out:
Al Viro0226f492011-12-06 12:21:54 -0500229 return err;
230}
231
232static int mounts_open_common(struct inode *inode, struct file *file,
233 int (*show)(struct seq_file *, struct vfsmount *))
234{
235 struct task_struct *task = get_proc_task(inode);
236 struct nsproxy *nsp;
237 struct mnt_namespace *ns = NULL;
238 struct path root;
239 struct proc_mounts *p;
Yann Droneaudede1bf02015-06-30 14:57:30 -0700240 struct seq_file *m;
Al Viro0226f492011-12-06 12:21:54 -0500241 int ret = -EINVAL;
242
243 if (!task)
244 goto err;
245
Eric W. Biederman728dba32014-02-03 19:13:49 -0800246 task_lock(task);
247 nsp = task->nsproxy;
Axel Lin3d931162014-01-23 15:55:44 -0800248 if (!nsp || !nsp->mnt_ns) {
Eric W. Biederman728dba32014-02-03 19:13:49 -0800249 task_unlock(task);
Al Viro0226f492011-12-06 12:21:54 -0500250 put_task_struct(task);
251 goto err;
252 }
253 ns = nsp->mnt_ns;
Al Viro0226f492011-12-06 12:21:54 -0500254 get_mnt_ns(ns);
Al Viro0226f492011-12-06 12:21:54 -0500255 if (!task->fs) {
256 task_unlock(task);
257 put_task_struct(task);
258 ret = -ENOENT;
259 goto err_put_ns;
260 }
261 get_fs_root(task->fs, &root);
262 task_unlock(task);
263 put_task_struct(task);
264
Yann Droneaudede1bf02015-06-30 14:57:30 -0700265 ret = seq_open_private(file, &mounts_op, sizeof(struct proc_mounts));
266 if (ret)
Al Viro0226f492011-12-06 12:21:54 -0500267 goto err_put_path;
268
Yann Droneaudede1bf02015-06-30 14:57:30 -0700269 m = file->private_data;
270 m->poll_event = ns->event;
Al Viro0226f492011-12-06 12:21:54 -0500271
Yann Droneaudede1bf02015-06-30 14:57:30 -0700272 p = m->private;
Al Viro0226f492011-12-06 12:21:54 -0500273 p->ns = ns;
274 p->root = root;
Al Viro0226f492011-12-06 12:21:54 -0500275 p->show = show;
Al Viroc7999c32014-02-27 14:40:10 -0500276 p->cached_event = ~0ULL;
Al Viro0226f492011-12-06 12:21:54 -0500277
278 return 0;
279
Al Viro0226f492011-12-06 12:21:54 -0500280 err_put_path:
281 path_put(&root);
282 err_put_ns:
283 put_mnt_ns(ns);
284 err:
285 return ret;
286}
287
288static int mounts_release(struct inode *inode, struct file *file)
289{
Yann Droneaudede1bf02015-06-30 14:57:30 -0700290 struct seq_file *m = file->private_data;
291 struct proc_mounts *p = m->private;
Al Viro0226f492011-12-06 12:21:54 -0500292 path_put(&p->root);
293 put_mnt_ns(p->ns);
Yann Droneaudede1bf02015-06-30 14:57:30 -0700294 return seq_release_private(inode, file);
Al Viro0226f492011-12-06 12:21:54 -0500295}
296
297static int mounts_open(struct inode *inode, struct file *file)
298{
299 return mounts_open_common(inode, file, show_vfsmnt);
300}
301
302static int mountinfo_open(struct inode *inode, struct file *file)
303{
304 return mounts_open_common(inode, file, show_mountinfo);
305}
306
307static int mountstats_open(struct inode *inode, struct file *file)
308{
309 return mounts_open_common(inode, file, show_vfsstat);
310}
311
312const struct file_operations proc_mounts_operations = {
313 .open = mounts_open,
314 .read = seq_read,
315 .llseek = seq_lseek,
316 .release = mounts_release,
317 .poll = mounts_poll,
318};
319
320const struct file_operations proc_mountinfo_operations = {
321 .open = mountinfo_open,
322 .read = seq_read,
323 .llseek = seq_lseek,
324 .release = mounts_release,
325 .poll = mounts_poll,
326};
327
328const struct file_operations proc_mountstats_operations = {
329 .open = mountstats_open,
330 .read = seq_read,
331 .llseek = seq_lseek,
332 .release = mounts_release,
333};