[mirror_ubuntu-bionic-kernel.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->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)) {
		ctx->pos = file->f_pos;
		res = file->f_op->iterate(file, ctx);
		file->f_pos = ctx->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;
2233f31a	27	if (!file->f_op \|\| !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)) {
2233f31a AV	40	ctx->pos = file->f_pos;
	41	res = file->f_op->iterate(file, ctx);
	42	file->f_pos = ctx->pos;
1da177e4 LT	43	file_accessed(file);
1da177e4 LT	44	}
1b1dcc1b	45	mutex_unlock(&inode->i_mutex);
1da177e4 LT	46	out:
	47	return res;
	48	}
5c0ba4e0	49	EXPORT_SYMBOL(iterate_dir);
1da177e4 LT	50
	51	/*
	52	* Traditional linux readdir() handling..
	53	*
	54	* "count=1" is a special case, meaning that the buffer is one
	55	* dirent-structure in size and that the code can't handle more
	56	* anyway. Thus the special "fillonedir()" function for that
	57	* case (the low-level handlers don't need to care about this).
	58	*/
1da177e4 LT	59
	60	#ifdef __ARCH_WANT_OLD_READDIR
	61
	62	struct old_linux_dirent {
	63	unsigned long d_ino;
	64	unsigned long d_offset;
	65	unsigned short d_namlen;
	66	char d_name[1];
	67	};
	68
	69	struct readdir_callback {
5c0ba4e0	70	struct dir_context ctx;
1da177e4 LT	71	struct old_linux_dirent __user * dirent;
	72	int result;
	73	};
	74
	75	static int fillonedir(void * __buf, const char * name, int namlen, loff_t offset,
afefdbb2	76	u64 ino, unsigned int d_type)
1da177e4	77	{
5c0ba4e0	78	struct readdir_callback buf = (struct readdir_callback ) __buf;
1da177e4	79	struct old_linux_dirent __user * dirent;
afefdbb2	80	unsigned long d_ino;
1da177e4 LT	81
	82	if (buf->result)
	83	return -EINVAL;
afefdbb2	84	d_ino = ino;
8f3f655d AV	85	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
8f3f655d AV	86	buf->result = -EOVERFLOW;
afefdbb2	87	return -EOVERFLOW;
8f3f655d	88	}
1da177e4 LT	89	buf->result++;
	90	dirent = buf->dirent;
	91	if (!access_ok(VERIFY_WRITE, dirent,
	92	(unsigned long)(dirent->d_name + namlen + 1) -
	93	(unsigned long)dirent))
	94	goto efault;
afefdbb2	95	if ( __put_user(d_ino, &dirent->d_ino) \|\|
1da177e4 LT	96	__put_user(offset, &dirent->d_offset) \|\|
	97	__put_user(namlen, &dirent->d_namlen) \|\|
	98	__copy_to_user(dirent->d_name, name, namlen) \|\|
	99	__put_user(0, dirent->d_name + namlen))
	100	goto efault;
	101	return 0;
	102	efault:
	103	buf->result = -EFAULT;
	104	return -EFAULT;
	105	}
	106
d4e82042 HC	107	SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
d4e82042 HC	108	struct old_linux_dirent __user *, dirent, unsigned int, count)
1da177e4 LT	109	{
1da177e4 LT	110	int error;
2903ff01	111	struct fd f = fdget(fd);
1da177e4 LT	112	struct readdir_callback buf;
1da177e4 LT	113
2903ff01	114	if (!f.file)
863ced7f	115	return -EBADF;
1da177e4	116
5c0ba4e0	117	buf.ctx.actor = fillonedir;
1da177e4 LT	118	buf.result = 0;
	119	buf.dirent = dirent;
	120
5c0ba4e0	121	error = iterate_dir(f.file, &buf.ctx);
53c9c5c0	122	if (buf.result)
1da177e4 LT	123	error = buf.result;
1da177e4 LT	124
2903ff01	125	fdput(f);
1da177e4 LT	126	return error;
	127	}
	128
	129	#endif /* __ARCH_WANT_OLD_READDIR */
	130
	131	/*
	132	* New, all-improved, singing, dancing, iBCS2-compliant getdents()
	133	* interface.
	134	*/
	135	struct linux_dirent {
	136	unsigned long d_ino;
	137	unsigned long d_off;
	138	unsigned short d_reclen;
	139	char d_name[1];
	140	};
	141
	142	struct getdents_callback {
5c0ba4e0	143	struct dir_context ctx;
1da177e4 LT	144	struct linux_dirent __user * current_dir;
	145	struct linux_dirent __user * previous;
	146	int count;
	147	int error;
	148	};
	149
	150	static int filldir(void * __buf, const char * name, int namlen, loff_t offset,
afefdbb2	151	u64 ino, unsigned int d_type)
1da177e4 LT	152	{
	153	struct linux_dirent __user * dirent;
	154	struct getdents_callback * buf = (struct getdents_callback *) __buf;
afefdbb2	155	unsigned long d_ino;
85c9fe8f KW	156	int reclen = ALIGN(offsetof(struct linux_dirent, d_name) + namlen + 2,
85c9fe8f KW	157	sizeof(long));
1da177e4 LT	158
	159	buf->error = -EINVAL; /* only used if we fail.. */
	160	if (reclen > buf->count)
	161	return -EINVAL;
afefdbb2	162	d_ino = ino;
8f3f655d AV	163	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
8f3f655d AV	164	buf->error = -EOVERFLOW;
afefdbb2	165	return -EOVERFLOW;
8f3f655d	166	}
1da177e4 LT	167	dirent = buf->previous;
	168	if (dirent) {
	169	if (__put_user(offset, &dirent->d_off))
	170	goto efault;
	171	}
	172	dirent = buf->current_dir;
afefdbb2	173	if (__put_user(d_ino, &dirent->d_ino))
1da177e4 LT	174	goto efault;
	175	if (__put_user(reclen, &dirent->d_reclen))
	176	goto efault;
	177	if (copy_to_user(dirent->d_name, name, namlen))
	178	goto efault;
	179	if (__put_user(0, dirent->d_name + namlen))
	180	goto efault;
	181	if (__put_user(d_type, (char __user *) dirent + reclen - 1))
	182	goto efault;
	183	buf->previous = dirent;
	184	dirent = (void __user *)dirent + reclen;
	185	buf->current_dir = dirent;
	186	buf->count -= reclen;
	187	return 0;
	188	efault:
	189	buf->error = -EFAULT;
	190	return -EFAULT;
	191	}
	192
20f37034 HC	193	SYSCALL_DEFINE3(getdents, unsigned int, fd,
20f37034 HC	194	struct linux_dirent __user *, dirent, unsigned int, count)
1da177e4	195	{
2903ff01	196	struct fd f;
1da177e4 LT	197	struct linux_dirent __user * lastdirent;
	198	struct getdents_callback buf;
	199	int error;
	200
1da177e4	201	if (!access_ok(VERIFY_WRITE, dirent, count))
863ced7f	202	return -EFAULT;
1da177e4	203
2903ff01 AV	204	f = fdget(fd);
2903ff01 AV	205	if (!f.file)
863ced7f	206	return -EBADF;
1da177e4 LT	207
	208	buf.current_dir = dirent;
	209	buf.previous = NULL;
	210	buf.count = count;
	211	buf.error = 0;
5c0ba4e0	212	buf.ctx.actor = filldir;
1da177e4	213
5c0ba4e0	214	error = iterate_dir(f.file, &buf.ctx);
53c9c5c0 AV	215	if (error >= 0)
53c9c5c0 AV	216	error = buf.error;
1da177e4 LT	217	lastdirent = buf.previous;
1da177e4 LT	218	if (lastdirent) {
bb6f619b	219	if (put_user(buf.ctx.pos, &lastdirent->d_off))
1da177e4 LT	220	error = -EFAULT;
	221	else
	222	error = count - buf.count;
	223	}
2903ff01	224	fdput(f);
1da177e4 LT	225	return error;
	226	}
	227
1da177e4	228	struct getdents_callback64 {
5c0ba4e0	229	struct dir_context ctx;
1da177e4 LT	230	struct linux_dirent64 __user * current_dir;
	231	struct linux_dirent64 __user * previous;
	232	int count;
	233	int error;
	234	};
	235
	236	static int filldir64(void * __buf, const char * name, int namlen, loff_t offset,
afefdbb2	237	u64 ino, unsigned int d_type)
1da177e4 LT	238	{
	239	struct linux_dirent64 __user *dirent;
	240	struct getdents_callback64 * buf = (struct getdents_callback64 *) __buf;
85c9fe8f KW	241	int reclen = ALIGN(offsetof(struct linux_dirent64, d_name) + namlen + 1,
85c9fe8f KW	242	sizeof(u64));
1da177e4 LT	243
	244	buf->error = -EINVAL; /* only used if we fail.. */
	245	if (reclen > buf->count)
	246	return -EINVAL;
	247	dirent = buf->previous;
	248	if (dirent) {
	249	if (__put_user(offset, &dirent->d_off))
	250	goto efault;
	251	}
	252	dirent = buf->current_dir;
	253	if (__put_user(ino, &dirent->d_ino))
	254	goto efault;
	255	if (__put_user(0, &dirent->d_off))
	256	goto efault;
	257	if (__put_user(reclen, &dirent->d_reclen))
	258	goto efault;
	259	if (__put_user(d_type, &dirent->d_type))
	260	goto efault;
	261	if (copy_to_user(dirent->d_name, name, namlen))
	262	goto efault;
	263	if (__put_user(0, dirent->d_name + namlen))
	264	goto efault;
	265	buf->previous = dirent;
	266	dirent = (void __user *)dirent + reclen;
	267	buf->current_dir = dirent;
	268	buf->count -= reclen;
	269	return 0;
	270	efault:
	271	buf->error = -EFAULT;
	272	return -EFAULT;
	273	}
	274
20f37034 HC	275	SYSCALL_DEFINE3(getdents64, unsigned int, fd,
20f37034 HC	276	struct linux_dirent64 __user *, dirent, unsigned int, count)
1da177e4	277	{
2903ff01	278	struct fd f;
1da177e4 LT	279	struct linux_dirent64 __user * lastdirent;
	280	struct getdents_callback64 buf;
	281	int error;
	282
1da177e4	283	if (!access_ok(VERIFY_WRITE, dirent, count))
863ced7f	284	return -EFAULT;
1da177e4	285
2903ff01 AV	286	f = fdget(fd);
2903ff01 AV	287	if (!f.file)
863ced7f	288	return -EBADF;
1da177e4 LT	289
	290	buf.current_dir = dirent;
	291	buf.previous = NULL;
	292	buf.count = count;
	293	buf.error = 0;
5c0ba4e0	294	buf.ctx.actor = filldir64;
1da177e4	295
5c0ba4e0	296	error = iterate_dir(f.file, &buf.ctx);
53c9c5c0 AV	297	if (error >= 0)
53c9c5c0 AV	298	error = buf.error;
1da177e4 LT	299	lastdirent = buf.previous;
1da177e4 LT	300	if (lastdirent) {
bb6f619b	301	typeof(lastdirent->d_off) d_off = buf.ctx.pos;
1da177e4	302	if (__put_user(d_off, &lastdirent->d_off))
53c9c5c0 AV	303	error = -EFAULT;
	304	else
	305	error = count - buf.count;
1da177e4	306	}
2903ff01	307	fdput(f);
1da177e4 LT	308	return error;
1da177e4 LT	309	}