[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;

	inode_lock(inode);
	// 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);
	}
	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 (__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 (__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);
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
9902af79 AV	35	inode_lock(inode);
	36	// res = mutex_lock_killable(&inode->i_mutex);
	37	// if (res)
	38	// goto out;
da784511	39
1da177e4 LT	40	res = -ENOENT;
1da177e4 LT	41	if (!IS_DEADDIR(inode)) {
2233f31a AV	42	ctx->pos = file->f_pos;
	43	res = file->f_op->iterate(file, ctx);
	44	file->f_pos = ctx->pos;
d4c7cf6c	45	fsnotify_access(file);
1da177e4 LT	46	file_accessed(file);
1da177e4 LT	47	}
5955102c	48	inode_unlock(inode);
1da177e4 LT	49	out:
	50	return res;
	51	}
5c0ba4e0	52	EXPORT_SYMBOL(iterate_dir);
1da177e4 LT	53
	54	/*
	55	* Traditional linux readdir() handling..
	56	*
	57	* "count=1" is a special case, meaning that the buffer is one
	58	* dirent-structure in size and that the code can't handle more
	59	* anyway. Thus the special "fillonedir()" function for that
	60	* case (the low-level handlers don't need to care about this).
	61	*/
1da177e4 LT	62
	63	#ifdef __ARCH_WANT_OLD_READDIR
	64
	65	struct old_linux_dirent {
	66	unsigned long d_ino;
	67	unsigned long d_offset;
	68	unsigned short d_namlen;
	69	char d_name[1];
	70	};
	71
	72	struct readdir_callback {
5c0ba4e0	73	struct dir_context ctx;
1da177e4 LT	74	struct old_linux_dirent __user * dirent;
	75	int result;
	76	};
	77
ac7576f4 MS	78	static int fillonedir(struct dir_context ctx, const char name, int namlen,
ac7576f4 MS	79	loff_t offset, u64 ino, unsigned int d_type)
1da177e4	80	{
ac7576f4 MS	81	struct readdir_callback *buf =
ac7576f4 MS	82	container_of(ctx, struct readdir_callback, ctx);
1da177e4	83	struct old_linux_dirent __user * dirent;
afefdbb2	84	unsigned long d_ino;
1da177e4 LT	85
	86	if (buf->result)
	87	return -EINVAL;
afefdbb2	88	d_ino = ino;
8f3f655d AV	89	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
8f3f655d AV	90	buf->result = -EOVERFLOW;
afefdbb2	91	return -EOVERFLOW;
8f3f655d	92	}
1da177e4 LT	93	buf->result++;
	94	dirent = buf->dirent;
	95	if (!access_ok(VERIFY_WRITE, dirent,
	96	(unsigned long)(dirent->d_name + namlen + 1) -
	97	(unsigned long)dirent))
	98	goto efault;
afefdbb2	99	if ( __put_user(d_ino, &dirent->d_ino) \|\|
1da177e4 LT	100	__put_user(offset, &dirent->d_offset) \|\|
	101	__put_user(namlen, &dirent->d_namlen) \|\|
	102	__copy_to_user(dirent->d_name, name, namlen) \|\|
	103	__put_user(0, dirent->d_name + namlen))
	104	goto efault;
	105	return 0;
	106	efault:
	107	buf->result = -EFAULT;
	108	return -EFAULT;
	109	}
	110
d4e82042 HC	111	SYSCALL_DEFINE3(old_readdir, unsigned int, fd,
d4e82042 HC	112	struct old_linux_dirent __user *, dirent, unsigned int, count)
1da177e4 LT	113	{
1da177e4 LT	114	int error;
63b6df14	115	struct fd f = fdget_pos(fd);
ac6614b7 AV	116	struct readdir_callback buf = {
	117	.ctx.actor = fillonedir,
	118	.dirent = dirent
	119	};
1da177e4	120
2903ff01	121	if (!f.file)
863ced7f	122	return -EBADF;
1da177e4	123
5c0ba4e0	124	error = iterate_dir(f.file, &buf.ctx);
53c9c5c0	125	if (buf.result)
1da177e4 LT	126	error = buf.result;
1da177e4 LT	127
63b6df14	128	fdput_pos(f);
1da177e4 LT	129	return error;
	130	}
	131
	132	#endif /* __ARCH_WANT_OLD_READDIR */
	133
	134	/*
	135	* New, all-improved, singing, dancing, iBCS2-compliant getdents()
	136	* interface.
	137	*/
	138	struct linux_dirent {
	139	unsigned long d_ino;
	140	unsigned long d_off;
	141	unsigned short d_reclen;
	142	char d_name[1];
	143	};
	144
	145	struct getdents_callback {
5c0ba4e0	146	struct dir_context ctx;
1da177e4 LT	147	struct linux_dirent __user * current_dir;
	148	struct linux_dirent __user * previous;
	149	int count;
	150	int error;
	151	};
	152
ac7576f4 MS	153	static int filldir(struct dir_context ctx, const char name, int namlen,
ac7576f4 MS	154	loff_t offset, u64 ino, unsigned int d_type)
1da177e4 LT	155	{
1da177e4 LT	156	struct linux_dirent __user * dirent;
ac7576f4 MS	157	struct getdents_callback *buf =
ac7576f4 MS	158	container_of(ctx, struct getdents_callback, ctx);
afefdbb2	159	unsigned long d_ino;
85c9fe8f KW	160	int reclen = ALIGN(offsetof(struct linux_dirent, d_name) + namlen + 2,
85c9fe8f KW	161	sizeof(long));
1da177e4 LT	162
	163	buf->error = -EINVAL; /* only used if we fail.. */
	164	if (reclen > buf->count)
	165	return -EINVAL;
afefdbb2	166	d_ino = ino;
8f3f655d AV	167	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
8f3f655d AV	168	buf->error = -EOVERFLOW;
afefdbb2	169	return -EOVERFLOW;
8f3f655d	170	}
1da177e4 LT	171	dirent = buf->previous;
	172	if (dirent) {
	173	if (__put_user(offset, &dirent->d_off))
	174	goto efault;
	175	}
	176	dirent = buf->current_dir;
afefdbb2	177	if (__put_user(d_ino, &dirent->d_ino))
1da177e4 LT	178	goto efault;
	179	if (__put_user(reclen, &dirent->d_reclen))
	180	goto efault;
	181	if (copy_to_user(dirent->d_name, name, namlen))
	182	goto efault;
	183	if (__put_user(0, dirent->d_name + namlen))
	184	goto efault;
	185	if (__put_user(d_type, (char __user *) dirent + reclen - 1))
	186	goto efault;
	187	buf->previous = dirent;
	188	dirent = (void __user *)dirent + reclen;
	189	buf->current_dir = dirent;
	190	buf->count -= reclen;
	191	return 0;
	192	efault:
	193	buf->error = -EFAULT;
	194	return -EFAULT;
	195	}
	196
20f37034 HC	197	SYSCALL_DEFINE3(getdents, unsigned int, fd,
20f37034 HC	198	struct linux_dirent __user *, dirent, unsigned int, count)
1da177e4	199	{
2903ff01	200	struct fd f;
1da177e4	201	struct linux_dirent __user * lastdirent;
ac6614b7 AV	202	struct getdents_callback buf = {
	203	.ctx.actor = filldir,
	204	.count = count,
	205	.current_dir = dirent
	206	};
1da177e4 LT	207	int error;
1da177e4 LT	208
1da177e4	209	if (!access_ok(VERIFY_WRITE, dirent, count))
863ced7f	210	return -EFAULT;
1da177e4	211
63b6df14	212	f = fdget_pos(fd);
2903ff01	213	if (!f.file)
863ced7f	214	return -EBADF;
1da177e4	215
5c0ba4e0	216	error = iterate_dir(f.file, &buf.ctx);
53c9c5c0 AV	217	if (error >= 0)
53c9c5c0 AV	218	error = buf.error;
1da177e4 LT	219	lastdirent = buf.previous;
1da177e4 LT	220	if (lastdirent) {
bb6f619b	221	if (put_user(buf.ctx.pos, &lastdirent->d_off))
1da177e4 LT	222	error = -EFAULT;
	223	else
	224	error = count - buf.count;
	225	}
63b6df14	226	fdput_pos(f);
1da177e4 LT	227	return error;
	228	}
	229
1da177e4	230	struct getdents_callback64 {
5c0ba4e0	231	struct dir_context ctx;
1da177e4 LT	232	struct linux_dirent64 __user * current_dir;
	233	struct linux_dirent64 __user * previous;
	234	int count;
	235	int error;
	236	};
	237
ac7576f4 MS	238	static int filldir64(struct dir_context ctx, const char name, int namlen,
ac7576f4 MS	239	loff_t offset, u64 ino, unsigned int d_type)
1da177e4 LT	240	{
1da177e4 LT	241	struct linux_dirent64 __user *dirent;
ac7576f4 MS	242	struct getdents_callback64 *buf =
ac7576f4 MS	243	container_of(ctx, struct getdents_callback64, ctx);
85c9fe8f KW	244	int reclen = ALIGN(offsetof(struct linux_dirent64, d_name) + namlen + 1,
85c9fe8f KW	245	sizeof(u64));
1da177e4 LT	246
	247	buf->error = -EINVAL; /* only used if we fail.. */
	248	if (reclen > buf->count)
	249	return -EINVAL;
	250	dirent = buf->previous;
	251	if (dirent) {
	252	if (__put_user(offset, &dirent->d_off))
	253	goto efault;
	254	}
	255	dirent = buf->current_dir;
	256	if (__put_user(ino, &dirent->d_ino))
	257	goto efault;
	258	if (__put_user(0, &dirent->d_off))
	259	goto efault;
	260	if (__put_user(reclen, &dirent->d_reclen))
	261	goto efault;
	262	if (__put_user(d_type, &dirent->d_type))
	263	goto efault;
	264	if (copy_to_user(dirent->d_name, name, namlen))
	265	goto efault;
	266	if (__put_user(0, dirent->d_name + namlen))
	267	goto efault;
	268	buf->previous = dirent;
	269	dirent = (void __user *)dirent + reclen;
	270	buf->current_dir = dirent;
	271	buf->count -= reclen;
	272	return 0;
	273	efault:
	274	buf->error = -EFAULT;
	275	return -EFAULT;
	276	}
	277
20f37034 HC	278	SYSCALL_DEFINE3(getdents64, unsigned int, fd,
20f37034 HC	279	struct linux_dirent64 __user *, dirent, unsigned int, count)
1da177e4	280	{
2903ff01	281	struct fd f;
1da177e4	282	struct linux_dirent64 __user * lastdirent;
ac6614b7 AV	283	struct getdents_callback64 buf = {
	284	.ctx.actor = filldir64,
	285	.count = count,
	286	.current_dir = dirent
	287	};
1da177e4 LT	288	int error;
1da177e4 LT	289
1da177e4	290	if (!access_ok(VERIFY_WRITE, dirent, count))
863ced7f	291	return -EFAULT;
1da177e4	292
63b6df14	293	f = fdget_pos(fd);
2903ff01	294	if (!f.file)
863ced7f	295	return -EBADF;
1da177e4	296
5c0ba4e0	297	error = iterate_dir(f.file, &buf.ctx);
53c9c5c0 AV	298	if (error >= 0)
53c9c5c0 AV	299	error = buf.error;
1da177e4 LT	300	lastdirent = buf.previous;
1da177e4 LT	301	if (lastdirent) {
bb6f619b	302	typeof(lastdirent->d_off) d_off = buf.ctx.pos;
1da177e4	303	if (__put_user(d_off, &lastdirent->d_off))
53c9c5c0 AV	304	error = -EFAULT;
	305	else
	306	error = count - buf.count;
1da177e4	307	}
63b6df14	308	fdput_pos(f);
1da177e4 LT	309	return error;
1da177e4 LT	310	}