2 * fs/proc_namespace.c - handling of /proc/<pid>/{mounts,mountinfo,mountstats}
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
9 #include <linux/mnt_namespace.h>
10 #include <linux/nsproxy.h>
11 #include <linux/security.h>
12 #include <linux/fs_struct.h>
13 #include <linux/sched/task.h>
15 #include "proc/internal.h" /* only for get_proc_task() in ->open() */
20 static unsigned mounts_poll(struct file *file, poll_table *wait)
22 struct seq_file *m = file->private_data;
23 struct proc_mounts *p = m->private;
24 struct mnt_namespace *ns = p->ns;
25 unsigned res = POLLIN | POLLRDNORM;
28 poll_wait(file, &p->ns->poll, wait);
30 event = ACCESS_ONCE(ns->event);
31 if (m->poll_event != event) {
32 m->poll_event = event;
33 res |= POLLERR | POLLPRI;
44 static int show_sb_opts(struct seq_file *m, struct super_block *sb)
46 static const struct proc_fs_info fs_info[] = {
47 { MS_SYNCHRONOUS, ",sync" },
48 { MS_DIRSYNC, ",dirsync" },
49 { MS_MANDLOCK, ",mand" },
50 { MS_LAZYTIME, ",lazytime" },
53 const struct proc_fs_info *fs_infop;
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);
60 return security_sb_show_options(m, sb);
63 static void show_mnt_opts(struct seq_file *m, struct vfsmount *mnt)
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" },
74 const struct proc_fs_info *fs_infop;
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);
82 static inline void mangle(struct seq_file *m, const char *s)
84 seq_escape(m, s, " \t\n\\");
87 static void show_type(struct seq_file *m, struct super_block *sb)
89 mangle(m, sb->s_type->name);
90 if (sb->s_subtype && sb->s_subtype[0]) {
92 mangle(m, sb->s_subtype);
96 static int show_vfsmnt(struct seq_file *m, struct vfsmount *mnt)
98 struct proc_mounts *p = m->private;
99 struct mount *r = real_mount(mnt);
100 struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
101 struct super_block *sb = mnt_path.dentry->d_sb;
104 if (sb->s_op->show_devname) {
105 err = sb->s_op->show_devname(m, mnt_path.dentry);
109 mangle(m, r->mnt_devname ? r->mnt_devname : "none");
112 /* mountpoints outside of chroot jail will give SEQ_SKIP on this */
113 err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
118 seq_puts(m, __mnt_is_readonly(mnt) ? " ro" : " rw");
119 err = show_sb_opts(m, sb);
122 show_mnt_opts(m, mnt);
123 if (sb->s_op->show_options)
124 err = sb->s_op->show_options(m, mnt_path.dentry);
125 seq_puts(m, " 0 0\n");
130 static int show_mountinfo(struct seq_file *m, struct vfsmount *mnt)
132 struct proc_mounts *p = m->private;
133 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 };
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));
140 if (sb->s_op->show_path) {
141 err = sb->s_op->show_path(m, mnt->mnt_root);
145 seq_dentry(m, mnt->mnt_root, " \t\n\\");
149 /* mountpoints outside of chroot jail will give SEQ_SKIP on this */
150 err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
154 seq_puts(m, mnt->mnt_flags & MNT_READONLY ? " ro" : " rw");
155 show_mnt_opts(m, mnt);
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);
167 if (IS_MNT_UNBINDABLE(r))
168 seq_puts(m, " unbindable");
170 /* Filesystem specific data */
174 if (sb->s_op->show_devname) {
175 err = sb->s_op->show_devname(m, mnt->mnt_root);
179 mangle(m, r->mnt_devname ? r->mnt_devname : "none");
181 seq_puts(m, sb->s_flags & MS_RDONLY ? " ro" : " rw");
182 err = show_sb_opts(m, sb);
185 if (sb->s_op->show_options)
186 err = sb->s_op->show_options(m, mnt->mnt_root);
192 static int show_vfsstat(struct seq_file *m, struct vfsmount *mnt)
194 struct proc_mounts *p = m->private;
195 struct mount *r = real_mount(mnt);
196 struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
197 struct super_block *sb = mnt_path.dentry->d_sb;
201 if (sb->s_op->show_devname) {
202 seq_puts(m, "device ");
203 err = sb->s_op->show_devname(m, mnt_path.dentry);
207 if (r->mnt_devname) {
208 seq_puts(m, "device ");
209 mangle(m, r->mnt_devname);
211 seq_puts(m, "no device");
215 seq_puts(m, " mounted on ");
216 /* mountpoints outside of chroot jail will give SEQ_SKIP on this */
217 err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
222 /* file system type */
223 seq_puts(m, "with fstype ");
226 /* optional statistics */
227 if (sb->s_op->show_stats) {
229 err = sb->s_op->show_stats(m, mnt_path.dentry);
237 static int mounts_open_common(struct inode *inode, struct file *file,
238 int (*show)(struct seq_file *, struct vfsmount *))
240 struct task_struct *task = get_proc_task(inode);
242 struct mnt_namespace *ns = NULL;
244 struct proc_mounts *p;
253 if (!nsp || !nsp->mnt_ns) {
255 put_task_struct(task);
262 put_task_struct(task);
266 get_fs_root(task->fs, &root);
268 put_task_struct(task);
270 ret = seq_open_private(file, &mounts_op, sizeof(struct proc_mounts));
274 m = file->private_data;
275 m->poll_event = ns->event;
281 p->cached_event = ~0ULL;
293 static int mounts_release(struct inode *inode, struct file *file)
295 struct seq_file *m = file->private_data;
296 struct proc_mounts *p = m->private;
299 return seq_release_private(inode, file);
302 static int mounts_open(struct inode *inode, struct file *file)
304 return mounts_open_common(inode, file, show_vfsmnt);
307 static int mountinfo_open(struct inode *inode, struct file *file)
309 return mounts_open_common(inode, file, show_mountinfo);
312 static int mountstats_open(struct inode *inode, struct file *file)
314 return mounts_open_common(inode, file, show_vfsstat);
317 const struct file_operations proc_mounts_operations = {
321 .release = mounts_release,
325 const struct file_operations proc_mountinfo_operations = {
326 .open = mountinfo_open,
329 .release = mounts_release,
333 const struct file_operations proc_mountstats_operations = {
334 .open = mountstats_open,
337 .release = mounts_release,