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 "proc/internal.h" /* only for get_proc_task() in ->open() */
18 static unsigned mounts_poll(struct file *file, poll_table *wait)
20 struct seq_file *m = file->private_data;
21 struct proc_mounts *p = m->private;
22 struct mnt_namespace *ns = p->ns;
23 unsigned res = POLLIN | POLLRDNORM;
26 poll_wait(file, &p->ns->poll, wait);
28 event = ACCESS_ONCE(ns->event);
29 if (m->poll_event != event) {
30 m->poll_event = event;
31 res |= POLLERR | POLLPRI;
42 static int show_sb_opts(struct seq_file *m, struct super_block *sb)
44 static const struct proc_fs_info fs_info[] = {
45 { MS_SYNCHRONOUS, ",sync" },
46 { MS_DIRSYNC, ",dirsync" },
47 { MS_MANDLOCK, ",mand" },
48 { MS_LAZYTIME, ",lazytime" },
51 const struct proc_fs_info *fs_infop;
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);
58 return security_sb_show_options(m, sb);
61 static void show_mnt_opts(struct seq_file *m, struct vfsmount *mnt)
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" },
72 const struct proc_fs_info *fs_infop;
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);
80 static inline void mangle(struct seq_file *m, const char *s)
82 seq_escape(m, s, " \t\n\\");
85 static void show_type(struct seq_file *m, struct super_block *sb)
87 mangle(m, sb->s_type->name);
88 if (sb->s_subtype && sb->s_subtype[0]) {
90 mangle(m, sb->s_subtype);
94 static int show_vfsmnt(struct seq_file *m, struct vfsmount *mnt)
96 struct proc_mounts *p = m->private;
97 struct mount *r = real_mount(mnt);
99 struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
100 struct super_block *sb = mnt_path.dentry->d_sb;
102 if (sb->s_op->show_devname) {
103 err = sb->s_op->show_devname(m, mnt_path.dentry);
107 mangle(m, r->mnt_devname ? r->mnt_devname : "none");
110 /* mountpoints outside of chroot jail will give SEQ_SKIP on this */
111 err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
116 seq_puts(m, __mnt_is_readonly(mnt) ? " ro" : " rw");
117 err = show_sb_opts(m, sb);
120 show_mnt_opts(m, mnt);
121 if (sb->s_op->show_options)
122 err = sb->s_op->show_options(m, mnt_path.dentry);
123 seq_puts(m, " 0 0\n");
128 static int show_mountinfo(struct seq_file *m, struct vfsmount *mnt)
130 struct proc_mounts *p = m->private;
131 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 };
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)
139 err = sb->s_op->show_path(m, mnt->mnt_root);
141 seq_dentry(m, mnt->mnt_root, " \t\n\\");
146 /* mountpoints outside of chroot jail will give SEQ_SKIP on this */
147 err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
151 seq_puts(m, mnt->mnt_flags & MNT_READONLY ? " ro" : " rw");
152 show_mnt_opts(m, mnt);
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);
164 if (IS_MNT_UNBINDABLE(r))
165 seq_puts(m, " unbindable");
167 /* Filesystem specific data */
171 if (sb->s_op->show_devname)
172 err = sb->s_op->show_devname(m, mnt->mnt_root);
174 mangle(m, r->mnt_devname ? r->mnt_devname : "none");
177 seq_puts(m, sb->s_flags & MS_RDONLY ? " ro" : " rw");
178 err = show_sb_opts(m, sb);
181 if (sb->s_op->show_options)
182 err = sb->s_op->show_options(m, mnt->mnt_root);
188 static int show_vfsstat(struct seq_file *m, struct vfsmount *mnt)
190 struct proc_mounts *p = m->private;
191 struct mount *r = real_mount(mnt);
192 struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
193 struct super_block *sb = mnt_path.dentry->d_sb;
197 if (sb->s_op->show_devname) {
198 seq_puts(m, "device ");
199 err = sb->s_op->show_devname(m, mnt_path.dentry);
203 if (r->mnt_devname) {
204 seq_puts(m, "device ");
205 mangle(m, r->mnt_devname);
207 seq_puts(m, "no device");
211 seq_puts(m, " mounted on ");
212 /* mountpoints outside of chroot jail will give SEQ_SKIP on this */
213 err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
218 /* file system type */
219 seq_puts(m, "with fstype ");
222 /* optional statistics */
223 if (sb->s_op->show_stats) {
226 err = sb->s_op->show_stats(m, mnt_path.dentry);
234 static int mounts_open_common(struct inode *inode, struct file *file,
235 int (*show)(struct seq_file *, struct vfsmount *))
237 struct task_struct *task = get_proc_task(inode);
239 struct mnt_namespace *ns = NULL;
241 struct proc_mounts *p;
250 if (!nsp || !nsp->mnt_ns) {
252 put_task_struct(task);
259 put_task_struct(task);
263 get_fs_root(task->fs, &root);
265 put_task_struct(task);
267 ret = seq_open_private(file, &mounts_op, sizeof(struct proc_mounts));
271 m = file->private_data;
272 m->poll_event = ns->event;
278 p->cached_event = ~0ULL;
290 static int mounts_release(struct inode *inode, struct file *file)
292 struct seq_file *m = file->private_data;
293 struct proc_mounts *p = m->private;
296 return seq_release_private(inode, file);
299 static int mounts_open(struct inode *inode, struct file *file)
301 return mounts_open_common(inode, file, show_vfsmnt);
304 static int mountinfo_open(struct inode *inode, struct file *file)
306 return mounts_open_common(inode, file, show_mountinfo);
309 static int mountstats_open(struct inode *inode, struct file *file)
311 return mounts_open_common(inode, file, show_vfsstat);
314 const struct file_operations proc_mounts_operations = {
318 .release = mounts_release,
322 const struct file_operations proc_mountinfo_operations = {
323 .open = mountinfo_open,
326 .release = mounts_release,
330 const struct file_operations proc_mountstats_operations = {
331 .open = mountstats_open,
334 .release = mounts_release,