[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/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);
	int res = -ENOTDIR;
	if (!file->f_op || (!file->f_op->readdir && !file->f_op->iterate))
		goto out;

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

	res = mutex_lock_killable(&inode->i_mutex);
	if (res)
		goto out;

	res = -ENOENT;
	if (!IS_DEADDIR(inode)) {
		if (file->f_op->iterate) {
			ctx->pos = file->f_pos;
			res = file->f_op->iterate(file, ctx);
			file->f_pos = ctx->pos;
		} else {
			res = file->f_op->readdir(file, ctx, ctx->actor);
			ctx->pos = file->f_pos;
		}
		file_accessed(file);
	}
	mutex_unlock(&inode->i_mutex);
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(void * __buf, const char * name, int namlen, loff_t offset,
		      u64 ino, unsigned int d_type)
{
	struct readdir_callback *buf = (struct readdir_callback *) __buf;
	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(fd);
	struct readdir_callback buf;

	if (!f.file)
		return -EBADF;

	buf.ctx.actor = fillonedir;
	buf.result = 0;
	buf.dirent = dirent;

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

	fdput(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(void * __buf, const char * name, int namlen, loff_t offset,
		   u64 ino, unsigned int d_type)
{
	struct linux_dirent __user * dirent;
	struct getdents_callback * buf = (struct getdents_callback *) __buf;
	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 (__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;
	int error;

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

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

	buf.current_dir = dirent;
	buf.previous = NULL;
	buf.count = count;
	buf.error = 0;
	buf.ctx.actor = filldir;

	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(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(void * __buf, const char * name, int namlen, loff_t offset,
		     u64 ino, unsigned int d_type)
{
	struct linux_dirent64 __user *dirent;
	struct getdents_callback64 * buf = (struct getdents_callback64 *) __buf;
	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 (__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;
	int error;

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

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

	buf.current_dir = dirent;
	buf.previous = NULL;
	buf.count = count;
	buf.error = 0;
	buf.ctx.actor = filldir64;

	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(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 LT	15	#include <linux/fs.h>
	16	#include <linux/dirent.h>
	17	#include <linux/security.h>
	18	#include <linux/syscalls.h>
	19	#include <linux/unistd.h>
	20
	21	#include <asm/uaccess.h>
	22
5c0ba4e0	23	int iterate_dir(struct file file, struct dir_context ctx)
1da177e4	24	{
496ad9aa	25	struct inode *inode = file_inode(file);
1da177e4	26	int res = -ENOTDIR;
bb6f619b	27	if (!file->f_op \|\| (!file->f_op->readdir && !file->f_op->iterate))
1da177e4 LT	28	goto out;
	29
	30	res = security_file_permission(file, MAY_READ);
	31	if (res)
	32	goto out;
	33
da784511 LH	34	res = mutex_lock_killable(&inode->i_mutex);
	35	if (res)
	36	goto out;
	37
1da177e4 LT	38	res = -ENOENT;
1da177e4 LT	39	if (!IS_DEADDIR(inode)) {
bb6f619b AV	40	if (file->f_op->iterate) {
	41	ctx->pos = file->f_pos;
	42	res = file->f_op->iterate(file, ctx);
	43	file->f_pos = ctx->pos;
	44	} else {
	45	res = file->f_op->readdir(file, ctx, ctx->actor);
	46	ctx->pos = file->f_pos;
	47	}
1da177e4 LT	48	file_accessed(file);
1da177e4 LT	49	}
1b1dcc1b	50	mutex_unlock(&inode->i_mutex);
1da177e4 LT	51	out:
	52	return res;
	53	}
5c0ba4e0	54	EXPORT_SYMBOL(iterate_dir);
1da177e4 LT	55
	56	/*
	57	* Traditional linux readdir() handling..
	58	*
	59	* "count=1" is a special case, meaning that the buffer is one
	60	* dirent-structure in size and that the code can't handle more
	61	* anyway. Thus the special "fillonedir()" function for that
	62	* case (the low-level handlers don't need to care about this).
	63	*/
1da177e4 LT	64
	65	#ifdef __ARCH_WANT_OLD_READDIR
	66
	67	struct old_linux_dirent {
	68	unsigned long d_ino;
	69	unsigned long d_offset;
	70	unsigned short d_namlen;
	71	char d_name[1];
	72	};
	73
	74	struct readdir_callback {
5c0ba4e0	75	struct dir_context ctx;
1da177e4 LT	76	struct old_linux_dirent __user * dirent;
	77	int result;
	78	};
	79
	80	static int fillonedir(void * __buf, const char * name, int namlen, loff_t offset,
afefdbb2	81	u64 ino, unsigned int d_type)
1da177e4	82	{
5c0ba4e0	83	struct readdir_callback buf = (struct readdir_callback ) __buf;
1da177e4	84	struct old_linux_dirent __user * dirent;
afefdbb2	85	unsigned long d_ino;
1da177e4 LT	86
	87	if (buf->result)
	88	return -EINVAL;
afefdbb2	89	d_ino = ino;
8f3f655d AV	90	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
8f3f655d AV	91	buf->result = -EOVERFLOW;
afefdbb2	92	return -EOVERFLOW;
8f3f655d	93	}
1da177e4 LT	94	buf->result++;
	95	dirent = buf->dirent;
	96	if (!access_ok(VERIFY_WRITE, dirent,
	97	(unsigned long)(dirent->d_name + namlen + 1) -
	98	(unsigned long)dirent))
	99	goto efault;
afefdbb2	100	if ( __put_user(d_ino, &dirent->d_ino) \|\|
1da177e4 LT	101	__put_user(offset, &dirent->d_offset) \|\|
	102	__put_user(namlen, &dirent->d_namlen) \|\|
	103	__copy_to_user(dirent->d_name, name, namlen) \|\|
	104	__put_user(0, dirent->d_name + namlen))
	105	goto efault;
	106	return 0;
	107	efault:
	108	buf->result = -EFAULT;
	109	return -EFAULT;
	110	}
	111
d4e82042 HC	112	SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
d4e82042 HC	113	struct old_linux_dirent __user *, dirent, unsigned int, count)
1da177e4 LT	114	{
1da177e4 LT	115	int error;
2903ff01	116	struct fd f = fdget(fd);
1da177e4 LT	117	struct readdir_callback buf;
1da177e4 LT	118
2903ff01	119	if (!f.file)
863ced7f	120	return -EBADF;
1da177e4	121
5c0ba4e0	122	buf.ctx.actor = fillonedir;
1da177e4 LT	123	buf.result = 0;
	124	buf.dirent = dirent;
	125
5c0ba4e0	126	error = iterate_dir(f.file, &buf.ctx);
53c9c5c0	127	if (buf.result)
1da177e4 LT	128	error = buf.result;
1da177e4 LT	129
2903ff01	130	fdput(f);
1da177e4 LT	131	return error;
	132	}
	133
	134	#endif /* __ARCH_WANT_OLD_READDIR */
	135
	136	/*
	137	* New, all-improved, singing, dancing, iBCS2-compliant getdents()
	138	* interface.
	139	*/
	140	struct linux_dirent {
	141	unsigned long d_ino;
	142	unsigned long d_off;
	143	unsigned short d_reclen;
	144	char d_name[1];
	145	};
	146
	147	struct getdents_callback {
5c0ba4e0	148	struct dir_context ctx;
1da177e4 LT	149	struct linux_dirent __user * current_dir;
	150	struct linux_dirent __user * previous;
	151	int count;
	152	int error;
	153	};
	154
	155	static int filldir(void * __buf, const char * name, int namlen, loff_t offset,
afefdbb2	156	u64 ino, unsigned int d_type)
1da177e4 LT	157	{
	158	struct linux_dirent __user * dirent;
	159	struct getdents_callback * buf = (struct getdents_callback *) __buf;
afefdbb2	160	unsigned long d_ino;
85c9fe8f KW	161	int reclen = ALIGN(offsetof(struct linux_dirent, d_name) + namlen + 2,
85c9fe8f KW	162	sizeof(long));
1da177e4 LT	163
	164	buf->error = -EINVAL; /* only used if we fail.. */
	165	if (reclen > buf->count)
	166	return -EINVAL;
afefdbb2	167	d_ino = ino;
8f3f655d AV	168	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
8f3f655d AV	169	buf->error = -EOVERFLOW;
afefdbb2	170	return -EOVERFLOW;
8f3f655d	171	}
1da177e4 LT	172	dirent = buf->previous;
	173	if (dirent) {
	174	if (__put_user(offset, &dirent->d_off))
	175	goto efault;
	176	}
	177	dirent = buf->current_dir;
afefdbb2	178	if (__put_user(d_ino, &dirent->d_ino))
1da177e4 LT	179	goto efault;
	180	if (__put_user(reclen, &dirent->d_reclen))
	181	goto efault;
	182	if (copy_to_user(dirent->d_name, name, namlen))
	183	goto efault;
	184	if (__put_user(0, dirent->d_name + namlen))
	185	goto efault;
	186	if (__put_user(d_type, (char __user *) dirent + reclen - 1))
	187	goto efault;
	188	buf->previous = dirent;
	189	dirent = (void __user *)dirent + reclen;
	190	buf->current_dir = dirent;
	191	buf->count -= reclen;
	192	return 0;
	193	efault:
	194	buf->error = -EFAULT;
	195	return -EFAULT;
	196	}
	197
20f37034 HC	198	SYSCALL_DEFINE3(getdents, unsigned int, fd,
20f37034 HC	199	struct linux_dirent __user *, dirent, unsigned int, count)
1da177e4	200	{
2903ff01	201	struct fd f;
1da177e4 LT	202	struct linux_dirent __user * lastdirent;
	203	struct getdents_callback buf;
	204	int error;
	205
1da177e4	206	if (!access_ok(VERIFY_WRITE, dirent, count))
863ced7f	207	return -EFAULT;
1da177e4	208
2903ff01 AV	209	f = fdget(fd);
2903ff01 AV	210	if (!f.file)
863ced7f	211	return -EBADF;
1da177e4 LT	212
	213	buf.current_dir = dirent;
	214	buf.previous = NULL;
	215	buf.count = count;
	216	buf.error = 0;
5c0ba4e0	217	buf.ctx.actor = filldir;
1da177e4	218
5c0ba4e0	219	error = iterate_dir(f.file, &buf.ctx);
53c9c5c0 AV	220	if (error >= 0)
53c9c5c0 AV	221	error = buf.error;
1da177e4 LT	222	lastdirent = buf.previous;
1da177e4 LT	223	if (lastdirent) {
bb6f619b	224	if (put_user(buf.ctx.pos, &lastdirent->d_off))
1da177e4 LT	225	error = -EFAULT;
	226	else
	227	error = count - buf.count;
	228	}
2903ff01	229	fdput(f);
1da177e4 LT	230	return error;
	231	}
	232
1da177e4	233	struct getdents_callback64 {
5c0ba4e0	234	struct dir_context ctx;
1da177e4 LT	235	struct linux_dirent64 __user * current_dir;
	236	struct linux_dirent64 __user * previous;
	237	int count;
	238	int error;
	239	};
	240
	241	static int filldir64(void * __buf, const char * name, int namlen, loff_t offset,
afefdbb2	242	u64 ino, unsigned int d_type)
1da177e4 LT	243	{
	244	struct linux_dirent64 __user *dirent;
	245	struct getdents_callback64 * buf = (struct getdents_callback64 *) __buf;
85c9fe8f KW	246	int reclen = ALIGN(offsetof(struct linux_dirent64, d_name) + namlen + 1,
85c9fe8f KW	247	sizeof(u64));
1da177e4 LT	248
	249	buf->error = -EINVAL; /* only used if we fail.. */
	250	if (reclen > buf->count)
	251	return -EINVAL;
	252	dirent = buf->previous;
	253	if (dirent) {
	254	if (__put_user(offset, &dirent->d_off))
	255	goto efault;
	256	}
	257	dirent = buf->current_dir;
	258	if (__put_user(ino, &dirent->d_ino))
	259	goto efault;
	260	if (__put_user(0, &dirent->d_off))
	261	goto efault;
	262	if (__put_user(reclen, &dirent->d_reclen))
	263	goto efault;
	264	if (__put_user(d_type, &dirent->d_type))
	265	goto efault;
	266	if (copy_to_user(dirent->d_name, name, namlen))
	267	goto efault;
	268	if (__put_user(0, dirent->d_name + namlen))
	269	goto efault;
	270	buf->previous = dirent;
	271	dirent = (void __user *)dirent + reclen;
	272	buf->current_dir = dirent;
	273	buf->count -= reclen;
	274	return 0;
	275	efault:
	276	buf->error = -EFAULT;
	277	return -EFAULT;
	278	}
	279
20f37034 HC	280	SYSCALL_DEFINE3(getdents64, unsigned int, fd,
20f37034 HC	281	struct linux_dirent64 __user *, dirent, unsigned int, count)
1da177e4	282	{
2903ff01	283	struct fd f;
1da177e4 LT	284	struct linux_dirent64 __user * lastdirent;
	285	struct getdents_callback64 buf;
	286	int error;
	287
1da177e4	288	if (!access_ok(VERIFY_WRITE, dirent, count))
863ced7f	289	return -EFAULT;
1da177e4	290
2903ff01 AV	291	f = fdget(fd);
2903ff01 AV	292	if (!f.file)
863ced7f	293	return -EBADF;
1da177e4 LT	294
	295	buf.current_dir = dirent;
	296	buf.previous = NULL;
	297	buf.count = count;
	298	buf.error = 0;
5c0ba4e0	299	buf.ctx.actor = filldir64;
1da177e4	300
5c0ba4e0	301	error = iterate_dir(f.file, &buf.ctx);
53c9c5c0 AV	302	if (error >= 0)
53c9c5c0 AV	303	error = buf.error;
1da177e4 LT	304	lastdirent = buf.previous;
1da177e4 LT	305	if (lastdirent) {
bb6f619b	306	typeof(lastdirent->d_off) d_off = buf.ctx.pos;
1da177e4	307	if (__put_user(d_off, &lastdirent->d_off))
53c9c5c0 AV	308	error = -EFAULT;
	309	else
	310	error = count - buf.count;
1da177e4	311	}
2903ff01	312	fdput(f);
1da177e4 LT	313	return error;
1da177e4 LT	314	}