[linux.git] / fs / readdir.c

/*
 *  linux/fs/readdir.c
 *
 *  Copyright (C) 1995  Linus Torvalds
 */

#include <linux/stddef.h>
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/time.h>
#include <linux/mm.h>
#include <linux/errno.h>
#include <linux/stat.h>
#include <linux/file.h>
#include <linux/fs.h>
#include <linux/fsnotify.h>
#include <linux/dirent.h>
#include <linux/security.h>
#include <linux/syscalls.h>
#include <linux/unistd.h>

#include <asm/uaccess.h>

int iterate_dir(struct file *file, struct dir_context *ctx)
{
	struct inode *inode = file_inode(file);
	bool shared = false;
	int res = -ENOTDIR;
	if (file->f_op->iterate_shared)
		shared = true;
	else if (!file->f_op->iterate)
		goto out;

	res = security_file_permission(file, MAY_READ);
	if (res)
		goto out;

	if (shared) {
		inode_lock_shared(inode);
	} else {
		res = down_write_killable(&inode->i_rwsem);
		if (res)
			goto out;
	}

	res = -ENOENT;
	if (!IS_DEADDIR(inode)) {
		ctx->pos = file->f_pos;
		if (shared)
			res = file->f_op->iterate_shared(file, ctx);
		else
			res = file->f_op->iterate(file, ctx);
		file->f_pos = ctx->pos;
		fsnotify_access(file);
		file_accessed(file);
	}
	if (shared)
		inode_unlock_shared(inode);
	else
		inode_unlock(inode);
out:
	return res;
}
EXPORT_SYMBOL(iterate_dir);

/*
 * Traditional linux readdir() handling..
 *
 * "count=1" is a special case, meaning that the buffer is one
 * dirent-structure in size and that the code can't handle more
 * anyway. Thus the special "fillonedir()" function for that
 * case (the low-level handlers don't need to care about this).
 */

#ifdef __ARCH_WANT_OLD_READDIR

struct old_linux_dirent {
	unsigned long	d_ino;
	unsigned long	d_offset;
	unsigned short	d_namlen;
	char		d_name[1];
};

struct readdir_callback {
	struct dir_context ctx;
	struct old_linux_dirent __user * dirent;
	int result;
};

static int fillonedir(struct dir_context *ctx, const char *name, int namlen,
		      loff_t offset, u64 ino, unsigned int d_type)
{
	struct readdir_callback *buf =
		container_of(ctx, struct readdir_callback, ctx);
	struct old_linux_dirent __user * dirent;
	unsigned long d_ino;

	if (buf->result)
		return -EINVAL;
	d_ino = ino;
	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
		buf->result = -EOVERFLOW;
		return -EOVERFLOW;
	}
	buf->result++;
	dirent = buf->dirent;
	if (!access_ok(VERIFY_WRITE, dirent,
			(unsigned long)(dirent->d_name + namlen + 1) -
				(unsigned long)dirent))
		goto efault;
	if (	__put_user(d_ino, &dirent->d_ino) ||
		__put_user(offset, &dirent->d_offset) ||
		__put_user(namlen, &dirent->d_namlen) ||
		__copy_to_user(dirent->d_name, name, namlen) ||
		__put_user(0, dirent->d_name + namlen))
		goto efault;
	return 0;
efault:
	buf->result = -EFAULT;
	return -EFAULT;
}

SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
		struct old_linux_dirent __user *, dirent, unsigned int, count)
{
	int error;
	struct fd f = fdget_pos(fd);
	struct readdir_callback buf = {
		.ctx.actor = fillonedir,
		.dirent = dirent
	};

	if (!f.file)
		return -EBADF;

	error = iterate_dir(f.file, &buf.ctx);
	if (buf.result)
		error = buf.result;

	fdput_pos(f);
	return error;
}

#endif /* __ARCH_WANT_OLD_READDIR */

/*
 * New, all-improved, singing, dancing, iBCS2-compliant getdents()
 * interface. 
 */
struct linux_dirent {
	unsigned long	d_ino;
	unsigned long	d_off;
	unsigned short	d_reclen;
	char		d_name[1];
};

struct getdents_callback {
	struct dir_context ctx;
	struct linux_dirent __user * current_dir;
	struct linux_dirent __user * previous;
	int count;
	int error;
};

static int filldir(struct dir_context *ctx, const char *name, int namlen,
		   loff_t offset, u64 ino, unsigned int d_type)
{
	struct linux_dirent __user * dirent;
	struct getdents_callback *buf =
		container_of(ctx, struct getdents_callback, ctx);
	unsigned long d_ino;
	int reclen = ALIGN(offsetof(struct linux_dirent, d_name) + namlen + 2,
		sizeof(long));

	buf->error = -EINVAL;	/* only used if we fail.. */
	if (reclen > buf->count)
		return -EINVAL;
	d_ino = ino;
	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
		buf->error = -EOVERFLOW;
		return -EOVERFLOW;
	}
	dirent = buf->previous;
	if (dirent) {
		if (signal_pending(current))
			return -EINTR;
		if (__put_user(offset, &dirent->d_off))
			goto efault;
	}
	dirent = buf->current_dir;
	if (__put_user(d_ino, &dirent->d_ino))
		goto efault;
	if (__put_user(reclen, &dirent->d_reclen))
		goto efault;
	if (copy_to_user(dirent->d_name, name, namlen))
		goto efault;
	if (__put_user(0, dirent->d_name + namlen))
		goto efault;
	if (__put_user(d_type, (char __user *) dirent + reclen - 1))
		goto efault;
	buf->previous = dirent;
	dirent = (void __user *)dirent + reclen;
	buf->current_dir = dirent;
	buf->count -= reclen;
	return 0;
efault:
	buf->error = -EFAULT;
	return -EFAULT;
}

SYSCALL_DEFINE3(getdents, unsigned int, fd,
		struct linux_dirent __user *, dirent, unsigned int, count)
{
	struct fd f;
	struct linux_dirent __user * lastdirent;
	struct getdents_callback buf = {
		.ctx.actor = filldir,
		.count = count,
		.current_dir = dirent
	};
	int error;

	if (!access_ok(VERIFY_WRITE, dirent, count))
		return -EFAULT;

	f = fdget_pos(fd);
	if (!f.file)
		return -EBADF;

	error = iterate_dir(f.file, &buf.ctx);
	if (error >= 0)
		error = buf.error;
	lastdirent = buf.previous;
	if (lastdirent) {
		if (put_user(buf.ctx.pos, &lastdirent->d_off))
			error = -EFAULT;
		else
			error = count - buf.count;
	}
	fdput_pos(f);
	return error;
}

struct getdents_callback64 {
	struct dir_context ctx;
	struct linux_dirent64 __user * current_dir;
	struct linux_dirent64 __user * previous;
	int count;
	int error;
};

static int filldir64(struct dir_context *ctx, const char *name, int namlen,
		     loff_t offset, u64 ino, unsigned int d_type)
{
	struct linux_dirent64 __user *dirent;
	struct getdents_callback64 *buf =
		container_of(ctx, struct getdents_callback64, ctx);
	int reclen = ALIGN(offsetof(struct linux_dirent64, d_name) + namlen + 1,
		sizeof(u64));

	buf->error = -EINVAL;	/* only used if we fail.. */
	if (reclen > buf->count)
		return -EINVAL;
	dirent = buf->previous;
	if (dirent) {
		if (signal_pending(current))
			return -EINTR;
		if (__put_user(offset, &dirent->d_off))
			goto efault;
	}
	dirent = buf->current_dir;
	if (__put_user(ino, &dirent->d_ino))
		goto efault;
	if (__put_user(0, &dirent->d_off))
		goto efault;
	if (__put_user(reclen, &dirent->d_reclen))
		goto efault;
	if (__put_user(d_type, &dirent->d_type))
		goto efault;
	if (copy_to_user(dirent->d_name, name, namlen))
		goto efault;
	if (__put_user(0, dirent->d_name + namlen))
		goto efault;
	buf->previous = dirent;
	dirent = (void __user *)dirent + reclen;
	buf->current_dir = dirent;
	buf->count -= reclen;
	return 0;
efault:
	buf->error = -EFAULT;
	return -EFAULT;
}

SYSCALL_DEFINE3(getdents64, unsigned int, fd,
		struct linux_dirent64 __user *, dirent, unsigned int, count)
{
	struct fd f;
	struct linux_dirent64 __user * lastdirent;
	struct getdents_callback64 buf = {
		.ctx.actor = filldir64,
		.count = count,
		.current_dir = dirent
	};
	int error;

	if (!access_ok(VERIFY_WRITE, dirent, count))
		return -EFAULT;

	f = fdget_pos(fd);
	if (!f.file)
		return -EBADF;

	error = iterate_dir(f.file, &buf.ctx);
	if (error >= 0)
		error = buf.error;
	lastdirent = buf.previous;
	if (lastdirent) {
		typeof(lastdirent->d_off) d_off = buf.ctx.pos;
		if (__put_user(d_off, &lastdirent->d_off))
			error = -EFAULT;
		else
			error = count - buf.count;
	}
	fdput_pos(f);
	return error;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/fs/readdir.c
	3	*
	4	* Copyright (C) 1995 Linus Torvalds
	5	*/
	6
85c9fe8f	7	#include <linux/stddef.h>
022a1692	8	#include <linux/kernel.h>
630d9c47	9	#include <linux/export.h>
1da177e4 LT	10	#include <linux/time.h>
	11	#include <linux/mm.h>
	12	#include <linux/errno.h>
	13	#include <linux/stat.h>
	14	#include <linux/file.h>
1da177e4	15	#include <linux/fs.h>
d4c7cf6c	16	#include <linux/fsnotify.h>
1da177e4 LT	17	#include <linux/dirent.h>
	18	#include <linux/security.h>
	19	#include <linux/syscalls.h>
	20	#include <linux/unistd.h>
	21
	22	#include <asm/uaccess.h>
	23
5c0ba4e0	24	int iterate_dir(struct file file, struct dir_context ctx)
1da177e4	25	{
496ad9aa	26	struct inode *inode = file_inode(file);
61922694	27	bool shared = false;
1da177e4	28	int res = -ENOTDIR;
61922694 AV	29	if (file->f_op->iterate_shared)
	30	shared = true;
	31	else if (!file->f_op->iterate)
1da177e4 LT	32	goto out;
	33
	34	res = security_file_permission(file, MAY_READ);
	35	if (res)
	36	goto out;
	37
00235411	38	if (shared) {
61922694	39	inode_lock_shared(inode);
00235411 AV	40	} else {
	41	res = down_write_killable(&inode->i_rwsem);
	42	if (res)
	43	goto out;
	44	}
da784511	45
1da177e4 LT	46	res = -ENOENT;
1da177e4 LT	47	if (!IS_DEADDIR(inode)) {
2233f31a	48	ctx->pos = file->f_pos;
61922694 AV	49	if (shared)
	50	res = file->f_op->iterate_shared(file, ctx);
	51	else
	52	res = file->f_op->iterate(file, ctx);
2233f31a	53	file->f_pos = ctx->pos;
d4c7cf6c	54	fsnotify_access(file);
1da177e4 LT	55	file_accessed(file);
1da177e4 LT	56	}
61922694 AV	57	if (shared)
	58	inode_unlock_shared(inode);
	59	else
	60	inode_unlock(inode);
1da177e4 LT	61	out:
	62	return res;
	63	}
5c0ba4e0	64	EXPORT_SYMBOL(iterate_dir);
1da177e4 LT	65
	66	/*
	67	* Traditional linux readdir() handling..
	68	*
	69	* "count=1" is a special case, meaning that the buffer is one
	70	* dirent-structure in size and that the code can't handle more
	71	* anyway. Thus the special "fillonedir()" function for that
	72	* case (the low-level handlers don't need to care about this).
	73	*/
1da177e4 LT	74
	75	#ifdef __ARCH_WANT_OLD_READDIR
	76
	77	struct old_linux_dirent {
	78	unsigned long d_ino;
	79	unsigned long d_offset;
	80	unsigned short d_namlen;
	81	char d_name[1];
	82	};
	83
	84	struct readdir_callback {
5c0ba4e0	85	struct dir_context ctx;
1da177e4 LT	86	struct old_linux_dirent __user * dirent;
	87	int result;
	88	};
	89
ac7576f4 MS	90	static int fillonedir(struct dir_context ctx, const char name, int namlen,
ac7576f4 MS	91	loff_t offset, u64 ino, unsigned int d_type)
1da177e4	92	{
ac7576f4 MS	93	struct readdir_callback *buf =
ac7576f4 MS	94	container_of(ctx, struct readdir_callback, ctx);
1da177e4	95	struct old_linux_dirent __user * dirent;
afefdbb2	96	unsigned long d_ino;
1da177e4 LT	97
	98	if (buf->result)
	99	return -EINVAL;
afefdbb2	100	d_ino = ino;
8f3f655d AV	101	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
8f3f655d AV	102	buf->result = -EOVERFLOW;
afefdbb2	103	return -EOVERFLOW;
8f3f655d	104	}
1da177e4 LT	105	buf->result++;
	106	dirent = buf->dirent;
	107	if (!access_ok(VERIFY_WRITE, dirent,
	108	(unsigned long)(dirent->d_name + namlen + 1) -
	109	(unsigned long)dirent))
	110	goto efault;
afefdbb2	111	if ( __put_user(d_ino, &dirent->d_ino) \|\|
1da177e4 LT	112	__put_user(offset, &dirent->d_offset) \|\|
	113	__put_user(namlen, &dirent->d_namlen) \|\|
	114	__copy_to_user(dirent->d_name, name, namlen) \|\|
	115	__put_user(0, dirent->d_name + namlen))
	116	goto efault;
	117	return 0;
	118	efault:
	119	buf->result = -EFAULT;
	120	return -EFAULT;
	121	}
	122
d4e82042 HC	123	SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
d4e82042 HC	124	struct old_linux_dirent __user *, dirent, unsigned int, count)
1da177e4 LT	125	{
1da177e4 LT	126	int error;
63b6df14	127	struct fd f = fdget_pos(fd);
ac6614b7 AV	128	struct readdir_callback buf = {
	129	.ctx.actor = fillonedir,
	130	.dirent = dirent
	131	};
1da177e4	132
2903ff01	133	if (!f.file)
863ced7f	134	return -EBADF;
1da177e4	135
5c0ba4e0	136	error = iterate_dir(f.file, &buf.ctx);
53c9c5c0	137	if (buf.result)
1da177e4 LT	138	error = buf.result;
1da177e4 LT	139
63b6df14	140	fdput_pos(f);
1da177e4 LT	141	return error;
	142	}
	143
	144	#endif /* __ARCH_WANT_OLD_READDIR */
	145
	146	/*
	147	* New, all-improved, singing, dancing, iBCS2-compliant getdents()
	148	* interface.
	149	*/
	150	struct linux_dirent {
	151	unsigned long d_ino;
	152	unsigned long d_off;
	153	unsigned short d_reclen;
	154	char d_name[1];
	155	};
	156
	157	struct getdents_callback {
5c0ba4e0	158	struct dir_context ctx;
1da177e4 LT	159	struct linux_dirent __user * current_dir;
	160	struct linux_dirent __user * previous;
	161	int count;
	162	int error;
	163	};
	164
ac7576f4 MS	165	static int filldir(struct dir_context ctx, const char name, int namlen,
ac7576f4 MS	166	loff_t offset, u64 ino, unsigned int d_type)
1da177e4 LT	167	{
1da177e4 LT	168	struct linux_dirent __user * dirent;
ac7576f4 MS	169	struct getdents_callback *buf =
ac7576f4 MS	170	container_of(ctx, struct getdents_callback, ctx);
afefdbb2	171	unsigned long d_ino;
85c9fe8f KW	172	int reclen = ALIGN(offsetof(struct linux_dirent, d_name) + namlen + 2,
85c9fe8f KW	173	sizeof(long));
1da177e4 LT	174
	175	buf->error = -EINVAL; /* only used if we fail.. */
	176	if (reclen > buf->count)
	177	return -EINVAL;
afefdbb2	178	d_ino = ino;
8f3f655d AV	179	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
8f3f655d AV	180	buf->error = -EOVERFLOW;
afefdbb2	181	return -EOVERFLOW;
8f3f655d	182	}
1da177e4 LT	183	dirent = buf->previous;
1da177e4 LT	184	if (dirent) {
1f60fbe7 TT	185	if (signal_pending(current))
1f60fbe7 TT	186	return -EINTR;
1da177e4 LT	187	if (__put_user(offset, &dirent->d_off))
	188	goto efault;
	189	}
	190	dirent = buf->current_dir;
afefdbb2	191	if (__put_user(d_ino, &dirent->d_ino))
1da177e4 LT	192	goto efault;
	193	if (__put_user(reclen, &dirent->d_reclen))
	194	goto efault;
	195	if (copy_to_user(dirent->d_name, name, namlen))
	196	goto efault;
	197	if (__put_user(0, dirent->d_name + namlen))
	198	goto efault;
	199	if (__put_user(d_type, (char __user *) dirent + reclen - 1))
	200	goto efault;
	201	buf->previous = dirent;
	202	dirent = (void __user *)dirent + reclen;
	203	buf->current_dir = dirent;
	204	buf->count -= reclen;
	205	return 0;
	206	efault:
	207	buf->error = -EFAULT;
	208	return -EFAULT;
	209	}
	210
20f37034 HC	211	SYSCALL_DEFINE3(getdents, unsigned int, fd,
20f37034 HC	212	struct linux_dirent __user *, dirent, unsigned int, count)
1da177e4	213	{
2903ff01	214	struct fd f;
1da177e4	215	struct linux_dirent __user * lastdirent;
ac6614b7 AV	216	struct getdents_callback buf = {
	217	.ctx.actor = filldir,
	218	.count = count,
	219	.current_dir = dirent
	220	};
1da177e4 LT	221	int error;
1da177e4 LT	222
1da177e4	223	if (!access_ok(VERIFY_WRITE, dirent, count))
863ced7f	224	return -EFAULT;
1da177e4	225
63b6df14	226	f = fdget_pos(fd);
2903ff01	227	if (!f.file)
863ced7f	228	return -EBADF;
1da177e4	229
5c0ba4e0	230	error = iterate_dir(f.file, &buf.ctx);
53c9c5c0 AV	231	if (error >= 0)
53c9c5c0 AV	232	error = buf.error;
1da177e4 LT	233	lastdirent = buf.previous;
1da177e4 LT	234	if (lastdirent) {
bb6f619b	235	if (put_user(buf.ctx.pos, &lastdirent->d_off))
1da177e4 LT	236	error = -EFAULT;
	237	else
	238	error = count - buf.count;
	239	}
63b6df14	240	fdput_pos(f);
1da177e4 LT	241	return error;
	242	}
	243
1da177e4	244	struct getdents_callback64 {
5c0ba4e0	245	struct dir_context ctx;
1da177e4 LT	246	struct linux_dirent64 __user * current_dir;
	247	struct linux_dirent64 __user * previous;
	248	int count;
	249	int error;
	250	};
	251
ac7576f4 MS	252	static int filldir64(struct dir_context ctx, const char name, int namlen,
ac7576f4 MS	253	loff_t offset, u64 ino, unsigned int d_type)
1da177e4 LT	254	{
1da177e4 LT	255	struct linux_dirent64 __user *dirent;
ac7576f4 MS	256	struct getdents_callback64 *buf =
ac7576f4 MS	257	container_of(ctx, struct getdents_callback64, ctx);
85c9fe8f KW	258	int reclen = ALIGN(offsetof(struct linux_dirent64, d_name) + namlen + 1,
85c9fe8f KW	259	sizeof(u64));
1da177e4 LT	260
	261	buf->error = -EINVAL; /* only used if we fail.. */
	262	if (reclen > buf->count)
	263	return -EINVAL;
	264	dirent = buf->previous;
	265	if (dirent) {
1f60fbe7 TT	266	if (signal_pending(current))
1f60fbe7 TT	267	return -EINTR;
1da177e4 LT	268	if (__put_user(offset, &dirent->d_off))
	269	goto efault;
	270	}
	271	dirent = buf->current_dir;
	272	if (__put_user(ino, &dirent->d_ino))
	273	goto efault;
	274	if (__put_user(0, &dirent->d_off))
	275	goto efault;
	276	if (__put_user(reclen, &dirent->d_reclen))
	277	goto efault;
	278	if (__put_user(d_type, &dirent->d_type))
	279	goto efault;
	280	if (copy_to_user(dirent->d_name, name, namlen))
	281	goto efault;
	282	if (__put_user(0, dirent->d_name + namlen))
	283	goto efault;
	284	buf->previous = dirent;
	285	dirent = (void __user *)dirent + reclen;
	286	buf->current_dir = dirent;
	287	buf->count -= reclen;
	288	return 0;
	289	efault:
	290	buf->error = -EFAULT;
	291	return -EFAULT;
	292	}
	293
20f37034 HC	294	SYSCALL_DEFINE3(getdents64, unsigned int, fd,
20f37034 HC	295	struct linux_dirent64 __user *, dirent, unsigned int, count)
1da177e4	296	{
2903ff01	297	struct fd f;
1da177e4	298	struct linux_dirent64 __user * lastdirent;
ac6614b7 AV	299	struct getdents_callback64 buf = {
	300	.ctx.actor = filldir64,
	301	.count = count,
	302	.current_dir = dirent
	303	};
1da177e4 LT	304	int error;
1da177e4 LT	305
1da177e4	306	if (!access_ok(VERIFY_WRITE, dirent, count))
863ced7f	307	return -EFAULT;
1da177e4	308
63b6df14	309	f = fdget_pos(fd);
2903ff01	310	if (!f.file)
863ced7f	311	return -EBADF;
1da177e4	312
5c0ba4e0	313	error = iterate_dir(f.file, &buf.ctx);
53c9c5c0 AV	314	if (error >= 0)
53c9c5c0 AV	315	error = buf.error;
1da177e4 LT	316	lastdirent = buf.previous;
1da177e4 LT	317	if (lastdirent) {
bb6f619b	318	typeof(lastdirent->d_off) d_off = buf.ctx.pos;
1da177e4	319	if (__put_user(d_off, &lastdirent->d_off))
53c9c5c0 AV	320	error = -EFAULT;
	321	else
	322	error = count - buf.count;
1da177e4	323	}
63b6df14	324	fdput_pos(f);
1da177e4 LT	325	return error;
1da177e4 LT	326	}