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 proc_mounts *p = proc_mounts(file->private_data);
21 struct mnt_namespace *ns = p->ns;
22 unsigned res = POLLIN | POLLRDNORM;
25 poll_wait(file, &p->ns->poll, wait);
27 event = ACCESS_ONCE(ns->event);
28 if (p->m.poll_event != event) {
29 p->m.poll_event = event;
30 res |= POLLERR | POLLPRI;
41 static int show_sb_opts(struct seq_file *m, struct super_block *sb)
43 static const struct proc_fs_info fs_info[] = {
44 { MS_SYNCHRONOUS, ",sync" },
45 { MS_DIRSYNC, ",dirsync" },
46 { MS_MANDLOCK, ",mand" },
47 { MS_LAZYTIME, ",lazytime" },
50 const struct proc_fs_info *fs_infop;
52 for (fs_infop = fs_info; fs_infop->flag; fs_infop++) {
53 if (sb->s_flags & fs_infop->flag)
54 seq_puts(m, fs_infop->str);
57 return security_sb_show_options(m, sb);
60 static void show_mnt_opts(struct seq_file *m, struct vfsmount *mnt)
62 static const struct proc_fs_info mnt_info[] = {
63 { MNT_NOSUID, ",nosuid" },
64 { MNT_NODEV, ",nodev" },
65 { MNT_NOEXEC, ",noexec" },
66 { MNT_NOATIME, ",noatime" },
67 { MNT_NODIRATIME, ",nodiratime" },
68 { MNT_RELATIME, ",relatime" },
71 const struct proc_fs_info *fs_infop;
73 for (fs_infop = mnt_info; fs_infop->flag; fs_infop++) {
74 if (mnt->mnt_flags & fs_infop->flag)
75 seq_puts(m, fs_infop->str);
79 static inline void mangle(struct seq_file *m, const char *s)
81 seq_escape(m, s, " \t\n\\");
84 static void show_type(struct seq_file *m, struct super_block *sb)
86 mangle(m, sb->s_type->name);
87 if (sb->s_subtype && sb->s_subtype[0]) {
89 mangle(m, sb->s_subtype);
93 static int show_vfsmnt(struct seq_file *m, struct vfsmount *mnt)
95 struct proc_mounts *p = proc_mounts(m);
96 struct mount *r = real_mount(mnt);
98 struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
99 struct super_block *sb = mnt_path.dentry->d_sb;
101 if (sb->s_op->show_devname) {
102 err = sb->s_op->show_devname(m, mnt_path.dentry);
106 mangle(m, r->mnt_devname ? r->mnt_devname : "none");
109 /* mountpoints outside of chroot jail will give SEQ_SKIP on this */
110 err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
115 seq_puts(m, __mnt_is_readonly(mnt) ? " ro" : " rw");
116 err = show_sb_opts(m, sb);
119 show_mnt_opts(m, mnt);
120 if (sb->s_op->show_options)
121 err = sb->s_op->show_options(m, mnt_path.dentry);
122 seq_puts(m, " 0 0\n");
127 static int show_mountinfo(struct seq_file *m, struct vfsmount *mnt)
129 struct proc_mounts *p = proc_mounts(m);
130 struct mount *r = real_mount(mnt);
131 struct super_block *sb = mnt->mnt_sb;
132 struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
135 seq_printf(m, "%i %i %u:%u ", r->mnt_id, r->mnt_parent->mnt_id,
136 MAJOR(sb->s_dev), MINOR(sb->s_dev));
137 if (sb->s_op->show_path)
138 err = sb->s_op->show_path(m, mnt->mnt_root);
140 seq_dentry(m, mnt->mnt_root, " \t\n\\");
145 /* mountpoints outside of chroot jail will give SEQ_SKIP on this */
146 err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
150 seq_puts(m, mnt->mnt_flags & MNT_READONLY ? " ro" : " rw");
151 show_mnt_opts(m, mnt);
153 /* Tagged fields ("foo:X" or "bar") */
154 if (IS_MNT_SHARED(r))
155 seq_printf(m, " shared:%i", r->mnt_group_id);
156 if (IS_MNT_SLAVE(r)) {
157 int master = r->mnt_master->mnt_group_id;
158 int dom = get_dominating_id(r, &p->root);
159 seq_printf(m, " master:%i", master);
160 if (dom && dom != master)
161 seq_printf(m, " propagate_from:%i", dom);
163 if (IS_MNT_UNBINDABLE(r))
164 seq_puts(m, " unbindable");
166 /* Filesystem specific data */
170 if (sb->s_op->show_devname)
171 err = sb->s_op->show_devname(m, mnt->mnt_root);
173 mangle(m, r->mnt_devname ? r->mnt_devname : "none");
176 seq_puts(m, sb->s_flags & MS_RDONLY ? " ro" : " rw");
177 err = show_sb_opts(m, sb);
180 if (sb->s_op->show_options)
181 err = sb->s_op->show_options(m, mnt->mnt_root);
187 static int show_vfsstat(struct seq_file *m, struct vfsmount *mnt)
189 struct proc_mounts *p = proc_mounts(m);
190 struct mount *r = real_mount(mnt);
191 struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
192 struct super_block *sb = mnt_path.dentry->d_sb;
196 if (sb->s_op->show_devname) {
197 seq_puts(m, "device ");
198 err = sb->s_op->show_devname(m, mnt_path.dentry);
200 if (r->mnt_devname) {
201 seq_puts(m, "device ");
202 mangle(m, r->mnt_devname);
204 seq_puts(m, "no device");
208 seq_puts(m, " mounted on ");
209 /* mountpoints outside of chroot jail will give SEQ_SKIP on this */
210 err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
215 /* file system type */
216 seq_puts(m, "with fstype ");
219 /* optional statistics */
220 if (sb->s_op->show_stats) {
223 err = sb->s_op->show_stats(m, mnt_path.dentry);
231 static int mounts_open_common(struct inode *inode, struct file *file,
232 int (*show)(struct seq_file *, struct vfsmount *))
234 struct task_struct *task = get_proc_task(inode);
236 struct mnt_namespace *ns = NULL;
238 struct proc_mounts *p;
246 if (!nsp || !nsp->mnt_ns) {
248 put_task_struct(task);
255 put_task_struct(task);
259 get_fs_root(task->fs, &root);
261 put_task_struct(task);
264 p = kmalloc(sizeof(struct proc_mounts), GFP_KERNEL);
268 file->private_data = &p->m;
269 ret = seq_open(file, &mounts_op);
275 p->m.poll_event = ns->event;
277 p->cached_event = ~0ULL;
291 static int mounts_release(struct inode *inode, struct file *file)
293 struct proc_mounts *p = proc_mounts(file->private_data);
296 return seq_release(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,