[mirror_ubuntu-zesty-kernel.git] / fs / proc_namespace.c

/*
 * fs/proc_namespace.c - handling of /proc/<pid>/{mounts,mountinfo,mountstats}
 *
 * In fact, that's a piece of procfs; it's *almost* isolated from
 * the rest of fs/proc, but has rather close relationships with
 * fs/namespace.c, thus here instead of fs/proc
 *
 */
#include <linux/mnt_namespace.h>
#include <linux/nsproxy.h>
#include <linux/security.h>
#include <linux/fs_struct.h>
#include "proc/internal.h" /* only for get_proc_task() in ->open() */

#include "pnode.h"
#include "internal.h"

static unsigned mounts_poll(struct file *file, poll_table *wait)
{
	struct proc_mounts *p = proc_mounts(file->private_data);
	struct mnt_namespace *ns = p->ns;
	unsigned res = POLLIN | POLLRDNORM;
	int event;

	poll_wait(file, &p->ns->poll, wait);

	event = ACCESS_ONCE(ns->event);
	if (p->m.poll_event != event) {
		p->m.poll_event = event;
		res |= POLLERR | POLLPRI;
	}

	return res;
}

struct proc_fs_info {
	int flag;
	const char *str;
};

static int show_sb_opts(struct seq_file *m, struct super_block *sb)
{
	static const struct proc_fs_info fs_info[] = {
		{ MS_SYNCHRONOUS, ",sync" },
		{ MS_DIRSYNC, ",dirsync" },
		{ MS_MANDLOCK, ",mand" },
		{ 0, NULL }
	};
	const struct proc_fs_info *fs_infop;

	for (fs_infop = fs_info; fs_infop->flag; fs_infop++) {
		if (sb->s_flags & fs_infop->flag)
			seq_puts(m, fs_infop->str);
	}

	return security_sb_show_options(m, sb);
}

static void show_mnt_opts(struct seq_file *m, struct vfsmount *mnt)
{
	static const struct proc_fs_info mnt_info[] = {
		{ MNT_NOSUID, ",nosuid" },
		{ MNT_NODEV, ",nodev" },
		{ MNT_NOEXEC, ",noexec" },
		{ MNT_NOATIME, ",noatime" },
		{ MNT_NODIRATIME, ",nodiratime" },
		{ MNT_RELATIME, ",relatime" },
		{ 0, NULL }
	};
	const struct proc_fs_info *fs_infop;

	for (fs_infop = mnt_info; fs_infop->flag; fs_infop++) {
		if (mnt->mnt_flags & fs_infop->flag)
			seq_puts(m, fs_infop->str);
	}
}

static inline void mangle(struct seq_file *m, const char *s)
{
	seq_escape(m, s, " \t\n\\");
}

static void show_type(struct seq_file *m, struct super_block *sb)
{
	mangle(m, sb->s_type->name);
	if (sb->s_subtype && sb->s_subtype[0]) {
		seq_putc(m, '.');
		mangle(m, sb->s_subtype);
	}
}

static int show_vfsmnt(struct seq_file *m, struct vfsmount *mnt)
{
	struct proc_mounts *p = proc_mounts(m);
	struct mount *r = real_mount(mnt);
	int err = 0;
	struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
	struct super_block *sb = mnt_path.dentry->d_sb;

	if (sb->s_op->show_devname) {
		err = sb->s_op->show_devname(m, mnt_path.dentry);
		if (err)
			goto out;
	} else {
		mangle(m, r->mnt_devname ? r->mnt_devname : "none");
	}
	seq_putc(m, ' ');
	/* mountpoints outside of chroot jail will give SEQ_SKIP on this */
	err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
	if (err)
		goto out;
	seq_putc(m, ' ');
	show_type(m, sb);
	seq_puts(m, __mnt_is_readonly(mnt) ? " ro" : " rw");
	err = show_sb_opts(m, sb);
	if (err)
		goto out;
	show_mnt_opts(m, mnt);
	if (sb->s_op->show_options)
		err = sb->s_op->show_options(m, mnt_path.dentry);
	seq_puts(m, " 0 0\n");
out:
	return err;
}

static int show_mountinfo(struct seq_file *m, struct vfsmount *mnt)
{
	struct proc_mounts *p = proc_mounts(m);
	struct mount *r = real_mount(mnt);
	struct super_block *sb = mnt->mnt_sb;
	struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
	int err = 0;

	seq_printf(m, "%i %i %u:%u ", r->mnt_id, r->mnt_parent->mnt_id,
		   MAJOR(sb->s_dev), MINOR(sb->s_dev));
	if (sb->s_op->show_path)
		err = sb->s_op->show_path(m, mnt->mnt_root);
	else
		seq_dentry(m, mnt->mnt_root, " \t\n\\");
	if (err)
		goto out;
	seq_putc(m, ' ');

	/* mountpoints outside of chroot jail will give SEQ_SKIP on this */
	err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
	if (err)
		goto out;

	seq_puts(m, mnt->mnt_flags & MNT_READONLY ? " ro" : " rw");
	show_mnt_opts(m, mnt);

	/* Tagged fields ("foo:X" or "bar") */
	if (IS_MNT_SHARED(r))
		seq_printf(m, " shared:%i", r->mnt_group_id);
	if (IS_MNT_SLAVE(r)) {
		int master = r->mnt_master->mnt_group_id;
		int dom = get_dominating_id(r, &p->root);
		seq_printf(m, " master:%i", master);
		if (dom && dom != master)
			seq_printf(m, " propagate_from:%i", dom);
	}
	if (IS_MNT_UNBINDABLE(r))
		seq_puts(m, " unbindable");

	/* Filesystem specific data */
	seq_puts(m, " - ");
	show_type(m, sb);
	seq_putc(m, ' ');
	if (sb->s_op->show_devname)
		err = sb->s_op->show_devname(m, mnt->mnt_root);
	else
		mangle(m, r->mnt_devname ? r->mnt_devname : "none");
	if (err)
		goto out;
	seq_puts(m, sb->s_flags & MS_RDONLY ? " ro" : " rw");
	err = show_sb_opts(m, sb);
	if (err)
		goto out;
	if (sb->s_op->show_options)
		err = sb->s_op->show_options(m, mnt->mnt_root);
	seq_putc(m, '\n');
out:
	return err;
}

static int show_vfsstat(struct seq_file *m, struct vfsmount *mnt)
{
	struct proc_mounts *p = proc_mounts(m);
	struct mount *r = real_mount(mnt);
	struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
	struct super_block *sb = mnt_path.dentry->d_sb;
	int err = 0;

	/* device */
	if (sb->s_op->show_devname) {
		seq_puts(m, "device ");
		err = sb->s_op->show_devname(m, mnt_path.dentry);
	} else {
		if (r->mnt_devname) {
			seq_puts(m, "device ");
			mangle(m, r->mnt_devname);
		} else
			seq_puts(m, "no device");
	}

	/* mount point */
	seq_puts(m, " mounted on ");
	/* mountpoints outside of chroot jail will give SEQ_SKIP on this */
	err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
	if (err)
		goto out;
	seq_putc(m, ' ');

	/* file system type */
	seq_puts(m, "with fstype ");
	show_type(m, sb);

	/* optional statistics */
	if (sb->s_op->show_stats) {
		seq_putc(m, ' ');
		if (!err)
			err = sb->s_op->show_stats(m, mnt_path.dentry);
	}

	seq_putc(m, '\n');
out:
	return err;
}

static int mounts_open_common(struct inode *inode, struct file *file,
			      int (*show)(struct seq_file *, struct vfsmount *))
{
	struct task_struct *task = get_proc_task(inode);
	struct nsproxy *nsp;
	struct mnt_namespace *ns = NULL;
	struct path root;
	struct proc_mounts *p;
	int ret = -EINVAL;

	if (!task)
		goto err;

	task_lock(task);
	nsp = task->nsproxy;
	if (!nsp || !nsp->mnt_ns) {
		task_unlock(task);
		put_task_struct(task);
		goto err;
	}
	ns = nsp->mnt_ns;
	get_mnt_ns(ns);
	if (!task->fs) {
		task_unlock(task);
		put_task_struct(task);
		ret = -ENOENT;
		goto err_put_ns;
	}
	get_fs_root(task->fs, &root);
	task_unlock(task);
	put_task_struct(task);

	ret = -ENOMEM;
	p = kmalloc(sizeof(struct proc_mounts), GFP_KERNEL);
	if (!p)
		goto err_put_path;

	file->private_data = &p->m;
	ret = seq_open(file, &mounts_op);
	if (ret)
		goto err_free;

	p->ns = ns;
	p->root = root;
	p->m.poll_event = ns->event;
	p->show = show;
	p->cached_event = ~0ULL;

	return 0;

 err_free:
	kfree(p);
 err_put_path:
	path_put(&root);
 err_put_ns:
	put_mnt_ns(ns);
 err:
	return ret;
}

static int mounts_release(struct inode *inode, struct file *file)
{
	struct proc_mounts *p = proc_mounts(file->private_data);
	path_put(&p->root);
	put_mnt_ns(p->ns);
	return seq_release(inode, file);
}

static int mounts_open(struct inode *inode, struct file *file)
{
	return mounts_open_common(inode, file, show_vfsmnt);
}

static int mountinfo_open(struct inode *inode, struct file *file)
{
	return mounts_open_common(inode, file, show_mountinfo);
}

static int mountstats_open(struct inode *inode, struct file *file)
{
	return mounts_open_common(inode, file, show_vfsstat);
}

const struct file_operations proc_mounts_operations = {
	.open		= mounts_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= mounts_release,
	.poll		= mounts_poll,
};

const struct file_operations proc_mountinfo_operations = {
	.open		= mountinfo_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= mounts_release,
	.poll		= mounts_poll,
};

const struct file_operations proc_mountstats_operations = {
	.open		= mountstats_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= mounts_release,
};
Commit	Line	Data
0226f492 AV	1	/*
	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
	18	static unsigned mounts_poll(struct file file, poll_table wait)
	19	{
6ce6e24e	20	struct proc_mounts *p = proc_mounts(file->private_data);
0226f492 AV	21	struct mnt_namespace *ns = p->ns;
0226f492 AV	22	unsigned res = POLLIN \| POLLRDNORM;
aab407fc	23	int event;
0226f492 AV	24
	25	poll_wait(file, &p->ns->poll, wait);
	26
aab407fc AV	27	event = ACCESS_ONCE(ns->event);
	28	if (p->m.poll_event != event) {
	29	p->m.poll_event = event;
0226f492 AV	30	res \|= POLLERR \| POLLPRI;
0226f492 AV	31	}
0226f492 AV	32
	33	return res;
	34	}
	35
	36	struct proc_fs_info {
	37	int flag;
	38	const char *str;
	39	};
	40
	41	static 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
	59	static 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
	78	static inline void mangle(struct seq_file m, const char s)
	79	{
	80	seq_escape(m, s, " \t\n\\");
	81	}
	82
	83	static 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
	92	static int show_vfsmnt(struct seq_file m, struct vfsmount mnt)
	93	{
9d4d6574	94	struct proc_mounts *p = proc_mounts(m);
0226f492 AV	95	struct mount *r = real_mount(mnt);
	96	int err = 0;
	97	struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
d861c630	98	struct super_block *sb = mnt_path.dentry->d_sb;
0226f492	99
d861c630 AV	100	if (sb->s_op->show_devname) {
d861c630 AV	101	err = sb->s_op->show_devname(m, mnt_path.dentry);
0226f492 AV	102	if (err)
	103	goto out;
	104	} else {
	105	mangle(m, r->mnt_devname ? r->mnt_devname : "none");
	106	}
	107	seq_putc(m, ' ');
9d4d6574 DL	108	/* mountpoints outside of chroot jail will give SEQ_SKIP on this */
	109	err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
	110	if (err)
	111	goto out;
0226f492	112	seq_putc(m, ' ');
d861c630	113	show_type(m, sb);
0226f492	114	seq_puts(m, __mnt_is_readonly(mnt) ? " ro" : " rw");
d861c630	115	err = show_sb_opts(m, sb);
0226f492 AV	116	if (err)
	117	goto out;
	118	show_mnt_opts(m, mnt);
d861c630	119	if (sb->s_op->show_options)
34c80b1d	120	err = sb->s_op->show_options(m, mnt_path.dentry);
0226f492 AV	121	seq_puts(m, " 0 0\n");
	122	out:
	123	return err;
	124	}
	125
	126	static int show_mountinfo(struct seq_file m, struct vfsmount mnt)
	127	{
6ce6e24e	128	struct proc_mounts *p = proc_mounts(m);
0226f492 AV	129	struct mount *r = real_mount(mnt);
	130	struct super_block *sb = mnt->mnt_sb;
	131	struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
0226f492 AV	132	int err = 0;
	133
	134	seq_printf(m, "%i %i %u:%u ", r->mnt_id, r->mnt_parent->mnt_id,
	135	MAJOR(sb->s_dev), MINOR(sb->s_dev));
	136	if (sb->s_op->show_path)
a6322de6	137	err = sb->s_op->show_path(m, mnt->mnt_root);
0226f492 AV	138	else
	139	seq_dentry(m, mnt->mnt_root, " \t\n\\");
	140	if (err)
	141	goto out;
	142	seq_putc(m, ' ');
	143
	144	/* mountpoints outside of chroot jail will give SEQ_SKIP on this */
9ad4dc4f	145	err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
0226f492 AV	146	if (err)
	147	goto out;
	148
	149	seq_puts(m, mnt->mnt_flags & MNT_READONLY ? " ro" : " rw");
	150	show_mnt_opts(m, mnt);
	151
	152	/* Tagged fields ("foo:X" or "bar") */
	153	if (IS_MNT_SHARED(r))
	154	seq_printf(m, " shared:%i", r->mnt_group_id);
	155	if (IS_MNT_SLAVE(r)) {
	156	int master = r->mnt_master->mnt_group_id;
	157	int dom = get_dominating_id(r, &p->root);
	158	seq_printf(m, " master:%i", master);
	159	if (dom && dom != master)
	160	seq_printf(m, " propagate_from:%i", dom);
	161	}
	162	if (IS_MNT_UNBINDABLE(r))
	163	seq_puts(m, " unbindable");
	164
	165	/* Filesystem specific data */
	166	seq_puts(m, " - ");
	167	show_type(m, sb);
	168	seq_putc(m, ' ');
	169	if (sb->s_op->show_devname)
d861c630	170	err = sb->s_op->show_devname(m, mnt->mnt_root);
0226f492 AV	171	else
	172	mangle(m, r->mnt_devname ? r->mnt_devname : "none");
	173	if (err)
	174	goto out;
	175	seq_puts(m, sb->s_flags & MS_RDONLY ? " ro" : " rw");
	176	err = show_sb_opts(m, sb);
	177	if (err)
	178	goto out;
	179	if (sb->s_op->show_options)
34c80b1d	180	err = sb->s_op->show_options(m, mnt->mnt_root);
0226f492 AV	181	seq_putc(m, '\n');
	182	out:
	183	return err;
	184	}
	185
	186	static int show_vfsstat(struct seq_file m, struct vfsmount mnt)
	187	{
9d4d6574	188	struct proc_mounts *p = proc_mounts(m);
0226f492 AV	189	struct mount *r = real_mount(mnt);
0226f492 AV	190	struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
64132379	191	struct super_block *sb = mnt_path.dentry->d_sb;
0226f492 AV	192	int err = 0;
	193
	194	/* device */
64132379	195	if (sb->s_op->show_devname) {
0226f492	196	seq_puts(m, "device ");
d861c630	197	err = sb->s_op->show_devname(m, mnt_path.dentry);
0226f492 AV	198	} else {
	199	if (r->mnt_devname) {
	200	seq_puts(m, "device ");
	201	mangle(m, r->mnt_devname);
	202	} else
	203	seq_puts(m, "no device");
	204	}
	205
	206	/* mount point */
	207	seq_puts(m, " mounted on ");
9d4d6574 DL	208	/* mountpoints outside of chroot jail will give SEQ_SKIP on this */
	209	err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
	210	if (err)
	211	goto out;
0226f492 AV	212	seq_putc(m, ' ');
	213
	214	/* file system type */
	215	seq_puts(m, "with fstype ");
64132379	216	show_type(m, sb);
0226f492 AV	217
0226f492 AV	218	/* optional statistics */
64132379	219	if (sb->s_op->show_stats) {
0226f492 AV	220	seq_putc(m, ' ');
0226f492 AV	221	if (!err)
64132379	222	err = sb->s_op->show_stats(m, mnt_path.dentry);
0226f492 AV	223	}
	224
	225	seq_putc(m, '\n');
9d4d6574	226	out:
0226f492 AV	227	return err;
	228	}
	229
	230	static int mounts_open_common(struct inode inode, struct file file,
	231	int (show)(struct seq_file , struct vfsmount *))
	232	{
	233	struct task_struct *task = get_proc_task(inode);
	234	struct nsproxy *nsp;
	235	struct mnt_namespace *ns = NULL;
	236	struct path root;
	237	struct proc_mounts *p;
	238	int ret = -EINVAL;
	239
	240	if (!task)
	241	goto err;
	242
728dba3a EB	243	task_lock(task);
728dba3a EB	244	nsp = task->nsproxy;
3d93116c	245	if (!nsp \|\| !nsp->mnt_ns) {
728dba3a	246	task_unlock(task);
0226f492 AV	247	put_task_struct(task);
	248	goto err;
	249	}
	250	ns = nsp->mnt_ns;
0226f492	251	get_mnt_ns(ns);
0226f492 AV	252	if (!task->fs) {
	253	task_unlock(task);
	254	put_task_struct(task);
	255	ret = -ENOENT;
	256	goto err_put_ns;
	257	}
	258	get_fs_root(task->fs, &root);
	259	task_unlock(task);
	260	put_task_struct(task);
	261
	262	ret = -ENOMEM;
	263	p = kmalloc(sizeof(struct proc_mounts), GFP_KERNEL);
	264	if (!p)
	265	goto err_put_path;
	266
	267	file->private_data = &p->m;
	268	ret = seq_open(file, &mounts_op);
	269	if (ret)
	270	goto err_free;
	271
0226f492 AV	272	p->ns = ns;
	273	p->root = root;
	274	p->m.poll_event = ns->event;
	275	p->show = show;
c7999c36	276	p->cached_event = ~0ULL;
0226f492 AV	277
	278	return 0;
	279
	280	err_free:
	281	kfree(p);
	282	err_put_path:
	283	path_put(&root);
	284	err_put_ns:
	285	put_mnt_ns(ns);
	286	err:
	287	return ret;
	288	}
	289
	290	static int mounts_release(struct inode inode, struct file file)
	291	{
6ce6e24e	292	struct proc_mounts *p = proc_mounts(file->private_data);
0226f492 AV	293	path_put(&p->root);
	294	put_mnt_ns(p->ns);
	295	return seq_release(inode, file);
	296	}
	297
	298	static int mounts_open(struct inode inode, struct file file)
	299	{
	300	return mounts_open_common(inode, file, show_vfsmnt);
	301	}
	302
	303	static int mountinfo_open(struct inode inode, struct file file)
	304	{
	305	return mounts_open_common(inode, file, show_mountinfo);
	306	}
	307
	308	static int mountstats_open(struct inode inode, struct file file)
	309	{
	310	return mounts_open_common(inode, file, show_vfsstat);
	311	}
	312
	313	const struct file_operations proc_mounts_operations = {
	314	.open = mounts_open,
	315	.read = seq_read,
	316	.llseek = seq_lseek,
	317	.release = mounts_release,
	318	.poll = mounts_poll,
	319	};
	320
	321	const struct file_operations proc_mountinfo_operations = {
	322	.open = mountinfo_open,
	323	.read = seq_read,
	324	.llseek = seq_lseek,
	325	.release = mounts_release,
	326	.poll = mounts_poll,
	327	};
	328
	329	const struct file_operations proc_mountstats_operations = {
	330	.open = mountstats_open,
	331	.read = seq_read,
	332	.llseek = seq_lseek,
	333	.release = mounts_release,
	334	};