[mirror_ubuntu-bionic-kernel.git] / fs / statfs.c

#include <linux/syscalls.h>
#include <linux/export.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/statfs.h>
#include <linux/security.h>
#include <linux/uaccess.h>
#include "internal.h"

static int flags_by_mnt(int mnt_flags)
{
	int flags = 0;

	if (mnt_flags & MNT_READONLY)
		flags |= ST_RDONLY;
	if (mnt_flags & MNT_NOSUID)
		flags |= ST_NOSUID;
	if (mnt_flags & MNT_NODEV)
		flags |= ST_NODEV;
	if (mnt_flags & MNT_NOEXEC)
		flags |= ST_NOEXEC;
	if (mnt_flags & MNT_NOATIME)
		flags |= ST_NOATIME;
	if (mnt_flags & MNT_NODIRATIME)
		flags |= ST_NODIRATIME;
	if (mnt_flags & MNT_RELATIME)
		flags |= ST_RELATIME;
	return flags;
}

static int flags_by_sb(int s_flags)
{
	int flags = 0;
	if (s_flags & MS_SYNCHRONOUS)
		flags |= ST_SYNCHRONOUS;
	if (s_flags & MS_MANDLOCK)
		flags |= ST_MANDLOCK;
	return flags;
}

static int calculate_f_flags(struct vfsmount *mnt)
{
	return ST_VALID | flags_by_mnt(mnt->mnt_flags) |
		flags_by_sb(mnt->mnt_sb->s_flags);
}

static int statfs_by_dentry(struct dentry *dentry, struct kstatfs *buf)
{
	int retval;

	if (!dentry->d_sb->s_op->statfs)
		return -ENOSYS;

	memset(buf, 0, sizeof(*buf));
	retval = security_sb_statfs(dentry);
	if (retval)
		return retval;
	retval = dentry->d_sb->s_op->statfs(dentry, buf);
	if (retval == 0 && buf->f_frsize == 0)
		buf->f_frsize = buf->f_bsize;
	return retval;
}

int vfs_statfs(struct path *path, struct kstatfs *buf)
{
	int error;

	error = statfs_by_dentry(path->dentry, buf);
	if (!error)
		buf->f_flags = calculate_f_flags(path->mnt);
	return error;
}
EXPORT_SYMBOL(vfs_statfs);

int user_statfs(const char __user *pathname, struct kstatfs *st)
{
	struct path path;
	int error;
	unsigned int lookup_flags = LOOKUP_FOLLOW|LOOKUP_AUTOMOUNT;
retry:
	error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
	if (!error) {
		error = vfs_statfs(&path, st);
		path_put(&path);
		if (retry_estale(error, lookup_flags)) {
			lookup_flags |= LOOKUP_REVAL;
			goto retry;
		}
	}
	return error;
}

int fd_statfs(int fd, struct kstatfs *st)
{
	struct fd f = fdget_raw(fd);
	int error = -EBADF;
	if (f.file) {
		error = vfs_statfs(&f.file->f_path, st);
		fdput(f);
	}
	return error;
}

static int do_statfs_native(struct kstatfs *st, struct statfs __user *p)
{
	struct statfs buf;

	if (sizeof(buf) == sizeof(*st))
		memcpy(&buf, st, sizeof(*st));
	else {
		if (sizeof buf.f_blocks == 4) {
			if ((st->f_blocks | st->f_bfree | st->f_bavail |
			     st->f_bsize | st->f_frsize) &
			    0xffffffff00000000ULL)
				return -EOVERFLOW;
			/*
			 * f_files and f_ffree may be -1; it's okay to stuff
			 * that into 32 bits
			 */
			if (st->f_files != -1 &&
			    (st->f_files & 0xffffffff00000000ULL))
				return -EOVERFLOW;
			if (st->f_ffree != -1 &&
			    (st->f_ffree & 0xffffffff00000000ULL))
				return -EOVERFLOW;
		}

		buf.f_type = st->f_type;
		buf.f_bsize = st->f_bsize;
		buf.f_blocks = st->f_blocks;
		buf.f_bfree = st->f_bfree;
		buf.f_bavail = st->f_bavail;
		buf.f_files = st->f_files;
		buf.f_ffree = st->f_ffree;
		buf.f_fsid = st->f_fsid;
		buf.f_namelen = st->f_namelen;
		buf.f_frsize = st->f_frsize;
		buf.f_flags = st->f_flags;
		memset(buf.f_spare, 0, sizeof(buf.f_spare));
	}
	if (copy_to_user(p, &buf, sizeof(buf)))
		return -EFAULT;
	return 0;
}

static int do_statfs64(struct kstatfs *st, struct statfs64 __user *p)
{
	struct statfs64 buf;
	if (sizeof(buf) == sizeof(*st))
		memcpy(&buf, st, sizeof(*st));
	else {
		buf.f_type = st->f_type;
		buf.f_bsize = st->f_bsize;
		buf.f_blocks = st->f_blocks;
		buf.f_bfree = st->f_bfree;
		buf.f_bavail = st->f_bavail;
		buf.f_files = st->f_files;
		buf.f_ffree = st->f_ffree;
		buf.f_fsid = st->f_fsid;
		buf.f_namelen = st->f_namelen;
		buf.f_frsize = st->f_frsize;
		buf.f_flags = st->f_flags;
		memset(buf.f_spare, 0, sizeof(buf.f_spare));
	}
	if (copy_to_user(p, &buf, sizeof(buf)))
		return -EFAULT;
	return 0;
}

SYSCALL_DEFINE2(statfs, const char __user *, pathname, struct statfs __user *, buf)
{
	struct kstatfs st;
	int error = user_statfs(pathname, &st);
	if (!error)
		error = do_statfs_native(&st, buf);
	return error;
}

SYSCALL_DEFINE3(statfs64, const char __user *, pathname, size_t, sz, struct statfs64 __user *, buf)
{
	struct kstatfs st;
	int error;
	if (sz != sizeof(*buf))
		return -EINVAL;
	error = user_statfs(pathname, &st);
	if (!error)
		error = do_statfs64(&st, buf);
	return error;
}

SYSCALL_DEFINE2(fstatfs, unsigned int, fd, struct statfs __user *, buf)
{
	struct kstatfs st;
	int error = fd_statfs(fd, &st);
	if (!error)
		error = do_statfs_native(&st, buf);
	return error;
}

SYSCALL_DEFINE3(fstatfs64, unsigned int, fd, size_t, sz, struct statfs64 __user *, buf)
{
	struct kstatfs st;
	int error;

	if (sz != sizeof(*buf))
		return -EINVAL;

	error = fd_statfs(fd, &st);
	if (!error)
		error = do_statfs64(&st, buf);
	return error;
}

int vfs_ustat(dev_t dev, struct kstatfs *sbuf)
{
	struct super_block *s = user_get_super(dev);
	int err;
	if (!s)
		return -EINVAL;

	err = statfs_by_dentry(s->s_root, sbuf);
	drop_super(s);
	return err;
}

SYSCALL_DEFINE2(ustat, unsigned, dev, struct ustat __user *, ubuf)
{
	struct ustat tmp;
	struct kstatfs sbuf;
	int err = vfs_ustat(new_decode_dev(dev), &sbuf);
	if (err)
		return err;

	memset(&tmp,0,sizeof(struct ustat));
	tmp.f_tfree = sbuf.f_bfree;
	tmp.f_tinode = sbuf.f_ffree;

	return copy_to_user(ubuf, &tmp, sizeof(struct ustat)) ? -EFAULT : 0;
}
Commit	Line	Data
7ed1ee61	1	#include <linux/syscalls.h>
630d9c47	2	#include <linux/export.h>
7ed1ee61 AV	3	#include <linux/fs.h>
7ed1ee61 AV	4	#include <linux/file.h>
365b1818	5	#include <linux/mount.h>
7ed1ee61 AV	6	#include <linux/namei.h>
	7	#include <linux/statfs.h>
	8	#include <linux/security.h>
	9	#include <linux/uaccess.h>
cf31e70d	10	#include "internal.h"
7ed1ee61	11
365b1818 CH	12	static int flags_by_mnt(int mnt_flags)
	13	{
	14	int flags = 0;
	15
	16	if (mnt_flags & MNT_READONLY)
	17	flags \|= ST_RDONLY;
	18	if (mnt_flags & MNT_NOSUID)
	19	flags \|= ST_NOSUID;
	20	if (mnt_flags & MNT_NODEV)
	21	flags \|= ST_NODEV;
	22	if (mnt_flags & MNT_NOEXEC)
	23	flags \|= ST_NOEXEC;
	24	if (mnt_flags & MNT_NOATIME)
	25	flags \|= ST_NOATIME;
	26	if (mnt_flags & MNT_NODIRATIME)
	27	flags \|= ST_NODIRATIME;
	28	if (mnt_flags & MNT_RELATIME)
	29	flags \|= ST_RELATIME;
	30	return flags;
	31	}
	32
	33	static int flags_by_sb(int s_flags)
	34	{
	35	int flags = 0;
	36	if (s_flags & MS_SYNCHRONOUS)
	37	flags \|= ST_SYNCHRONOUS;
	38	if (s_flags & MS_MANDLOCK)
	39	flags \|= ST_MANDLOCK;
	40	return flags;
	41	}
	42
	43	static int calculate_f_flags(struct vfsmount *mnt)
	44	{
	45	return ST_VALID \| flags_by_mnt(mnt->mnt_flags) \|
	46	flags_by_sb(mnt->mnt_sb->s_flags);
	47	}
	48
cf31e70d	49	static int statfs_by_dentry(struct dentry dentry, struct kstatfs buf)
7ed1ee61	50	{
ebabe9a9 CH	51	int retval;
	52
	53	if (!dentry->d_sb->s_op->statfs)
	54	return -ENOSYS;
	55
	56	memset(buf, 0, sizeof(*buf));
	57	retval = security_sb_statfs(dentry);
	58	if (retval)
	59	return retval;
	60	retval = dentry->d_sb->s_op->statfs(dentry, buf);
	61	if (retval == 0 && buf->f_frsize == 0)
	62	buf->f_frsize = buf->f_bsize;
7ed1ee61 AV	63	return retval;
	64	}
	65
ebabe9a9 CH	66	int vfs_statfs(struct path path, struct kstatfs buf)
ebabe9a9 CH	67	{
365b1818 CH	68	int error;
	69
	70	error = statfs_by_dentry(path->dentry, buf);
	71	if (!error)
	72	buf->f_flags = calculate_f_flags(path->mnt);
	73	return error;
ebabe9a9	74	}
7ed1ee61 AV	75	EXPORT_SYMBOL(vfs_statfs);
7ed1ee61 AV	76
c8b91acc	77	int user_statfs(const char __user pathname, struct kstatfs st)
7ed1ee61	78	{
c8b91acc	79	struct path path;
96948fc6 JL	80	int error;
	81	unsigned int lookup_flags = LOOKUP_FOLLOW\|LOOKUP_AUTOMOUNT;
	82	retry:
	83	error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
c8b91acc AV	84	if (!error) {
	85	error = vfs_statfs(&path, st);
	86	path_put(&path);
96948fc6 JL	87	if (retry_estale(error, lookup_flags)) {
	88	lookup_flags \|= LOOKUP_REVAL;
	89	goto retry;
	90	}
c8b91acc AV	91	}
	92	return error;
	93	}
7ed1ee61	94
c8b91acc AV	95	int fd_statfs(int fd, struct kstatfs *st)
c8b91acc AV	96	{
9d05746e	97	struct fd f = fdget_raw(fd);
c8b91acc	98	int error = -EBADF;
2903ff01 AV	99	if (f.file) {
	100	error = vfs_statfs(&f.file->f_path, st);
	101	fdput(f);
c8b91acc AV	102	}
	103	return error;
	104	}
7ed1ee61	105
c8b91acc AV	106	static int do_statfs_native(struct kstatfs st, struct statfs __user p)
	107	{
	108	struct statfs buf;
	109
	110	if (sizeof(buf) == sizeof(*st))
	111	memcpy(&buf, st, sizeof(*st));
7ed1ee61	112	else {
c8b91acc AV	113	if (sizeof buf.f_blocks == 4) {
	114	if ((st->f_blocks \| st->f_bfree \| st->f_bavail \|
	115	st->f_bsize \| st->f_frsize) &
7ed1ee61 AV	116	0xffffffff00000000ULL)
	117	return -EOVERFLOW;
	118	/*
	119	* f_files and f_ffree may be -1; it's okay to stuff
	120	* that into 32 bits
	121	*/
c8b91acc AV	122	if (st->f_files != -1 &&
c8b91acc AV	123	(st->f_files & 0xffffffff00000000ULL))
7ed1ee61	124	return -EOVERFLOW;
c8b91acc AV	125	if (st->f_ffree != -1 &&
c8b91acc AV	126	(st->f_ffree & 0xffffffff00000000ULL))
7ed1ee61 AV	127	return -EOVERFLOW;
	128	}
	129
c8b91acc AV	130	buf.f_type = st->f_type;
	131	buf.f_bsize = st->f_bsize;
	132	buf.f_blocks = st->f_blocks;
	133	buf.f_bfree = st->f_bfree;
	134	buf.f_bavail = st->f_bavail;
	135	buf.f_files = st->f_files;
	136	buf.f_ffree = st->f_ffree;
	137	buf.f_fsid = st->f_fsid;
	138	buf.f_namelen = st->f_namelen;
	139	buf.f_frsize = st->f_frsize;
	140	buf.f_flags = st->f_flags;
	141	memset(buf.f_spare, 0, sizeof(buf.f_spare));
7ed1ee61	142	}
c8b91acc AV	143	if (copy_to_user(p, &buf, sizeof(buf)))
c8b91acc AV	144	return -EFAULT;
7ed1ee61 AV	145	return 0;
	146	}
	147
c8b91acc	148	static int do_statfs64(struct kstatfs st, struct statfs64 __user p)
7ed1ee61	149	{
c8b91acc AV	150	struct statfs64 buf;
	151	if (sizeof(buf) == sizeof(*st))
	152	memcpy(&buf, st, sizeof(*st));
7ed1ee61	153	else {
c8b91acc AV	154	buf.f_type = st->f_type;
	155	buf.f_bsize = st->f_bsize;
	156	buf.f_blocks = st->f_blocks;
	157	buf.f_bfree = st->f_bfree;
	158	buf.f_bavail = st->f_bavail;
	159	buf.f_files = st->f_files;
	160	buf.f_ffree = st->f_ffree;
	161	buf.f_fsid = st->f_fsid;
	162	buf.f_namelen = st->f_namelen;
	163	buf.f_frsize = st->f_frsize;
	164	buf.f_flags = st->f_flags;
	165	memset(buf.f_spare, 0, sizeof(buf.f_spare));
7ed1ee61	166	}
c8b91acc AV	167	if (copy_to_user(p, &buf, sizeof(buf)))
c8b91acc AV	168	return -EFAULT;
7ed1ee61 AV	169	return 0;
	170	}
	171
	172	SYSCALL_DEFINE2(statfs, const char __user , pathname, struct statfs __user , buf)
	173	{
c8b91acc AV	174	struct kstatfs st;
	175	int error = user_statfs(pathname, &st);
	176	if (!error)
	177	error = do_statfs_native(&st, buf);
7ed1ee61 AV	178	return error;
	179	}
	180
	181	SYSCALL_DEFINE3(statfs64, const char __user , pathname, size_t, sz, struct statfs64 __user , buf)
	182	{
c8b91acc AV	183	struct kstatfs st;
c8b91acc AV	184	int error;
7ed1ee61 AV	185	if (sz != sizeof(*buf))
7ed1ee61 AV	186	return -EINVAL;
c8b91acc AV	187	error = user_statfs(pathname, &st);
	188	if (!error)
	189	error = do_statfs64(&st, buf);
7ed1ee61 AV	190	return error;
	191	}
	192
	193	SYSCALL_DEFINE2(fstatfs, unsigned int, fd, struct statfs __user *, buf)
	194	{
c8b91acc AV	195	struct kstatfs st;
	196	int error = fd_statfs(fd, &st);
	197	if (!error)
	198	error = do_statfs_native(&st, buf);
7ed1ee61 AV	199	return error;
	200	}
	201
	202	SYSCALL_DEFINE3(fstatfs64, unsigned int, fd, size_t, sz, struct statfs64 __user *, buf)
	203	{
c8b91acc	204	struct kstatfs st;
7ed1ee61 AV	205	int error;
	206
	207	if (sz != sizeof(*buf))
	208	return -EINVAL;
	209
c8b91acc AV	210	error = fd_statfs(fd, &st);
	211	if (!error)
	212	error = do_statfs64(&st, buf);
7ed1ee61 AV	213	return error;
	214	}
	215
cf31e70d	216	int vfs_ustat(dev_t dev, struct kstatfs *sbuf)
7ed1ee61	217	{
cf31e70d	218	struct super_block *s = user_get_super(dev);
7ed1ee61	219	int err;
7ed1ee61 AV	220	if (!s)
	221	return -EINVAL;
	222
cf31e70d	223	err = statfs_by_dentry(s->s_root, sbuf);
7ed1ee61	224	drop_super(s);
cf31e70d AV	225	return err;
	226	}
	227
	228	SYSCALL_DEFINE2(ustat, unsigned, dev, struct ustat __user *, ubuf)
	229	{
	230	struct ustat tmp;
	231	struct kstatfs sbuf;
	232	int err = vfs_ustat(new_decode_dev(dev), &sbuf);
7ed1ee61 AV	233	if (err)
	234	return err;
	235
	236	memset(&tmp,0,sizeof(struct ustat));
	237	tmp.f_tfree = sbuf.f_bfree;
	238	tmp.f_tinode = sbuf.f_ffree;
	239
	240	return copy_to_user(ubuf, &tmp, sizeof(struct ustat)) ? -EFAULT : 0;
	241	}