[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/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);
	int res = -ENOTDIR;
	if (!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;
		fsnotify_access(file);
		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 = {
		.ctx.actor = fillonedir,
		.dirent = dirent
	};

	if (!f.file)
		return -EBADF;

	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 = {
		.ctx.actor = filldir,
		.count = count,
		.current_dir = dirent
	};
	int error;

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

	f = fdget(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(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 = {
		.ctx.actor = filldir64,
		.count = count,
		.current_dir = dirent
	};
	int error;

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

	f = fdget(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(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);
1da177e4	27	int res = -ENOTDIR;
72c2d531	28	if (!file->f_op->iterate)
1da177e4 LT	29	goto out;
	30
	31	res = security_file_permission(file, MAY_READ);
	32	if (res)
	33	goto out;
	34
da784511 LH	35	res = mutex_lock_killable(&inode->i_mutex);
	36	if (res)
	37	goto out;
	38
1da177e4 LT	39	res = -ENOENT;
1da177e4 LT	40	if (!IS_DEADDIR(inode)) {
2233f31a AV	41	ctx->pos = file->f_pos;
	42	res = file->f_op->iterate(file, ctx);
	43	file->f_pos = ctx->pos;
d4c7cf6c	44	fsnotify_access(file);
1da177e4 LT	45	file_accessed(file);
1da177e4 LT	46	}
1b1dcc1b	47	mutex_unlock(&inode->i_mutex);
1da177e4 LT	48	out:
	49	return res;
	50	}
5c0ba4e0	51	EXPORT_SYMBOL(iterate_dir);
1da177e4 LT	52
	53	/*
	54	* Traditional linux readdir() handling..
	55	*
	56	* "count=1" is a special case, meaning that the buffer is one
	57	* dirent-structure in size and that the code can't handle more
	58	* anyway. Thus the special "fillonedir()" function for that
	59	* case (the low-level handlers don't need to care about this).
	60	*/
1da177e4 LT	61
	62	#ifdef __ARCH_WANT_OLD_READDIR
	63
	64	struct old_linux_dirent {
	65	unsigned long d_ino;
	66	unsigned long d_offset;
	67	unsigned short d_namlen;
	68	char d_name[1];
	69	};
	70
	71	struct readdir_callback {
5c0ba4e0	72	struct dir_context ctx;
1da177e4 LT	73	struct old_linux_dirent __user * dirent;
	74	int result;
	75	};
	76
	77	static int fillonedir(void * __buf, const char * name, int namlen, loff_t offset,
afefdbb2	78	u64 ino, unsigned int d_type)
1da177e4	79	{
5c0ba4e0	80	struct readdir_callback buf = (struct readdir_callback ) __buf;
1da177e4	81	struct old_linux_dirent __user * dirent;
afefdbb2	82	unsigned long d_ino;
1da177e4 LT	83
	84	if (buf->result)
	85	return -EINVAL;
afefdbb2	86	d_ino = ino;
8f3f655d AV	87	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
8f3f655d AV	88	buf->result = -EOVERFLOW;
afefdbb2	89	return -EOVERFLOW;
8f3f655d	90	}
1da177e4 LT	91	buf->result++;
	92	dirent = buf->dirent;
	93	if (!access_ok(VERIFY_WRITE, dirent,
	94	(unsigned long)(dirent->d_name + namlen + 1) -
	95	(unsigned long)dirent))
	96	goto efault;
afefdbb2	97	if ( __put_user(d_ino, &dirent->d_ino) \|\|
1da177e4 LT	98	__put_user(offset, &dirent->d_offset) \|\|
	99	__put_user(namlen, &dirent->d_namlen) \|\|
	100	__copy_to_user(dirent->d_name, name, namlen) \|\|
	101	__put_user(0, dirent->d_name + namlen))
	102	goto efault;
	103	return 0;
	104	efault:
	105	buf->result = -EFAULT;
	106	return -EFAULT;
	107	}
	108
d4e82042 HC	109	SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
d4e82042 HC	110	struct old_linux_dirent __user *, dirent, unsigned int, count)
1da177e4 LT	111	{
1da177e4 LT	112	int error;
2903ff01	113	struct fd f = fdget(fd);
ac6614b7 AV	114	struct readdir_callback buf = {
	115	.ctx.actor = fillonedir,
	116	.dirent = dirent
	117	};
1da177e4	118
2903ff01	119	if (!f.file)
863ced7f	120	return -EBADF;
1da177e4	121
5c0ba4e0	122	error = iterate_dir(f.file, &buf.ctx);
53c9c5c0	123	if (buf.result)
1da177e4 LT	124	error = buf.result;
1da177e4 LT	125
2903ff01	126	fdput(f);
1da177e4 LT	127	return error;
	128	}
	129
	130	#endif /* __ARCH_WANT_OLD_READDIR */
	131
	132	/*
	133	* New, all-improved, singing, dancing, iBCS2-compliant getdents()
	134	* interface.
	135	*/
	136	struct linux_dirent {
	137	unsigned long d_ino;
	138	unsigned long d_off;
	139	unsigned short d_reclen;
	140	char d_name[1];
	141	};
	142
	143	struct getdents_callback {
5c0ba4e0	144	struct dir_context ctx;
1da177e4 LT	145	struct linux_dirent __user * current_dir;
	146	struct linux_dirent __user * previous;
	147	int count;
	148	int error;
	149	};
	150
	151	static int filldir(void * __buf, const char * name, int namlen, loff_t offset,
afefdbb2	152	u64 ino, unsigned int d_type)
1da177e4 LT	153	{
	154	struct linux_dirent __user * dirent;
	155	struct getdents_callback * buf = (struct getdents_callback *) __buf;
afefdbb2	156	unsigned long d_ino;
85c9fe8f KW	157	int reclen = ALIGN(offsetof(struct linux_dirent, d_name) + namlen + 2,
85c9fe8f KW	158	sizeof(long));
1da177e4 LT	159
	160	buf->error = -EINVAL; /* only used if we fail.. */
	161	if (reclen > buf->count)
	162	return -EINVAL;
afefdbb2	163	d_ino = ino;
8f3f655d AV	164	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
8f3f655d AV	165	buf->error = -EOVERFLOW;
afefdbb2	166	return -EOVERFLOW;
8f3f655d	167	}
1da177e4 LT	168	dirent = buf->previous;
	169	if (dirent) {
	170	if (__put_user(offset, &dirent->d_off))
	171	goto efault;
	172	}
	173	dirent = buf->current_dir;
afefdbb2	174	if (__put_user(d_ino, &dirent->d_ino))
1da177e4 LT	175	goto efault;
	176	if (__put_user(reclen, &dirent->d_reclen))
	177	goto efault;
	178	if (copy_to_user(dirent->d_name, name, namlen))
	179	goto efault;
	180	if (__put_user(0, dirent->d_name + namlen))
	181	goto efault;
	182	if (__put_user(d_type, (char __user *) dirent + reclen - 1))
	183	goto efault;
	184	buf->previous = dirent;
	185	dirent = (void __user *)dirent + reclen;
	186	buf->current_dir = dirent;
	187	buf->count -= reclen;
	188	return 0;
	189	efault:
	190	buf->error = -EFAULT;
	191	return -EFAULT;
	192	}
	193
20f37034 HC	194	SYSCALL_DEFINE3(getdents, unsigned int, fd,
20f37034 HC	195	struct linux_dirent __user *, dirent, unsigned int, count)
1da177e4	196	{
2903ff01	197	struct fd f;
1da177e4	198	struct linux_dirent __user * lastdirent;
ac6614b7 AV	199	struct getdents_callback buf = {
	200	.ctx.actor = filldir,
	201	.count = count,
	202	.current_dir = dirent
	203	};
1da177e4 LT	204	int error;
1da177e4 LT	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	212
5c0ba4e0	213	error = iterate_dir(f.file, &buf.ctx);
53c9c5c0 AV	214	if (error >= 0)
53c9c5c0 AV	215	error = buf.error;
1da177e4 LT	216	lastdirent = buf.previous;
1da177e4 LT	217	if (lastdirent) {
bb6f619b	218	if (put_user(buf.ctx.pos, &lastdirent->d_off))
1da177e4 LT	219	error = -EFAULT;
	220	else
	221	error = count - buf.count;
	222	}
2903ff01	223	fdput(f);
1da177e4 LT	224	return error;
	225	}
	226
1da177e4	227	struct getdents_callback64 {
5c0ba4e0	228	struct dir_context ctx;
1da177e4 LT	229	struct linux_dirent64 __user * current_dir;
	230	struct linux_dirent64 __user * previous;
	231	int count;
	232	int error;
	233	};
	234
	235	static int filldir64(void * __buf, const char * name, int namlen, loff_t offset,
afefdbb2	236	u64 ino, unsigned int d_type)
1da177e4 LT	237	{
	238	struct linux_dirent64 __user *dirent;
	239	struct getdents_callback64 * buf = (struct getdents_callback64 *) __buf;
85c9fe8f KW	240	int reclen = ALIGN(offsetof(struct linux_dirent64, d_name) + namlen + 1,
85c9fe8f KW	241	sizeof(u64));
1da177e4 LT	242
	243	buf->error = -EINVAL; /* only used if we fail.. */
	244	if (reclen > buf->count)
	245	return -EINVAL;
	246	dirent = buf->previous;
	247	if (dirent) {
	248	if (__put_user(offset, &dirent->d_off))
	249	goto efault;
	250	}
	251	dirent = buf->current_dir;
	252	if (__put_user(ino, &dirent->d_ino))
	253	goto efault;
	254	if (__put_user(0, &dirent->d_off))
	255	goto efault;
	256	if (__put_user(reclen, &dirent->d_reclen))
	257	goto efault;
	258	if (__put_user(d_type, &dirent->d_type))
	259	goto efault;
	260	if (copy_to_user(dirent->d_name, name, namlen))
	261	goto efault;
	262	if (__put_user(0, dirent->d_name + namlen))
	263	goto efault;
	264	buf->previous = dirent;
	265	dirent = (void __user *)dirent + reclen;
	266	buf->current_dir = dirent;
	267	buf->count -= reclen;
	268	return 0;
	269	efault:
	270	buf->error = -EFAULT;
	271	return -EFAULT;
	272	}
	273
20f37034 HC	274	SYSCALL_DEFINE3(getdents64, unsigned int, fd,
20f37034 HC	275	struct linux_dirent64 __user *, dirent, unsigned int, count)
1da177e4	276	{
2903ff01	277	struct fd f;
1da177e4	278	struct linux_dirent64 __user * lastdirent;
ac6614b7 AV	279	struct getdents_callback64 buf = {
	280	.ctx.actor = filldir64,
	281	.count = count,
	282	.current_dir = dirent
	283	};
1da177e4 LT	284	int error;
1da177e4 LT	285
1da177e4	286	if (!access_ok(VERIFY_WRITE, dirent, count))
863ced7f	287	return -EFAULT;
1da177e4	288
2903ff01 AV	289	f = fdget(fd);
2903ff01 AV	290	if (!f.file)
863ced7f	291	return -EBADF;
1da177e4	292
5c0ba4e0	293	error = iterate_dir(f.file, &buf.ctx);
53c9c5c0 AV	294	if (error >= 0)
53c9c5c0 AV	295	error = buf.error;
1da177e4 LT	296	lastdirent = buf.previous;
1da177e4 LT	297	if (lastdirent) {
bb6f619b	298	typeof(lastdirent->d_off) d_off = buf.ctx.pos;
1da177e4	299	if (__put_user(d_off, &lastdirent->d_off))
53c9c5c0 AV	300	error = -EFAULT;
	301	else
	302	error = count - buf.count;
1da177e4	303	}
2903ff01	304	fdput(f);
1da177e4 LT	305	return error;
1da177e4 LT	306	}