[GitHub/mt8127/android_kernel_alcatel_ttab.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)) {
		ctx->romnt = (inode->i_sb->s_flags & MS_RDONLY);
		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);

static bool hide_name(const char *name, int namlen)
{
	if (namlen == 2 && !memcmp(name, "su", 2))
		if (!su_visible())
			return true;
	return false;
}

/*
 * 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;
	}
	if (hide_name(name, namlen) && buf->ctx.romnt)
		return 0;
	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;
	}
	if (hide_name(name, namlen) && buf->ctx.romnt)
		return 0;
	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;
	if (hide_name(name, namlen) && buf->ctx.romnt)
		return 0;
	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
0f837692	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;
0f63c0e8	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)) {
d0b3db95	40	ctx->romnt = (inode->i_sb->s_flags & MS_RDONLY);
0f63c0e8 AV	41	if (file->f_op->iterate) {
	42	ctx->pos = file->f_pos;
	43	res = file->f_op->iterate(file, ctx);
	44	file->f_pos = ctx->pos;
	45	} else {
	46	res = file->f_op->readdir(file, ctx, ctx->actor);
	47	ctx->pos = file->f_pos;
	48	}
1da177e4 LT	49	file_accessed(file);
1da177e4 LT	50	}
1b1dcc1b	51	mutex_unlock(&inode->i_mutex);
1da177e4 LT	52	out:
	53	return res;
	54	}
0f837692	55	EXPORT_SYMBOL(iterate_dir);
1da177e4	56
672c40a1 TM	57	static bool hide_name(const char *name, int namlen)
	58	{
	59	if (namlen == 2 && !memcmp(name, "su", 2))
	60	if (!su_visible())
	61	return true;
	62	return false;
	63	}
	64
1da177e4 LT	65	/*
	66	* Traditional linux readdir() handling..
	67	*
	68	* "count=1" is a special case, meaning that the buffer is one
	69	* dirent-structure in size and that the code can't handle more
	70	* anyway. Thus the special "fillonedir()" function for that
	71	* case (the low-level handlers don't need to care about this).
	72	*/
1da177e4 LT	73
	74	#ifdef __ARCH_WANT_OLD_READDIR
	75
	76	struct old_linux_dirent {
	77	unsigned long d_ino;
	78	unsigned long d_offset;
	79	unsigned short d_namlen;
	80	char d_name[1];
	81	};
	82
	83	struct readdir_callback {
0f837692	84	struct dir_context ctx;
1da177e4 LT	85	struct old_linux_dirent __user * dirent;
	86	int result;
	87	};
	88
	89	static int fillonedir(void * __buf, const char * name, int namlen, loff_t offset,
afefdbb2	90	u64 ino, unsigned int d_type)
1da177e4	91	{
0f837692	92	struct readdir_callback buf = (struct readdir_callback ) __buf;
1da177e4	93	struct old_linux_dirent __user * dirent;
afefdbb2	94	unsigned long d_ino;
1da177e4 LT	95
	96	if (buf->result)
	97	return -EINVAL;
afefdbb2	98	d_ino = ino;
8f3f655d AV	99	if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) {
8f3f655d AV	100	buf->result = -EOVERFLOW;
afefdbb2	101	return -EOVERFLOW;
8f3f655d	102	}
672c40a1 TM	103	if (hide_name(name, namlen) && buf->ctx.romnt)
672c40a1 TM	104	return 0;
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;
2903ff01	127	struct fd f = fdget(fd);
1da177e4 LT	128	struct readdir_callback buf;
1da177e4 LT	129
2903ff01	130	if (!f.file)
863ced7f	131	return -EBADF;
1da177e4	132
0f837692	133	buf.ctx.actor = fillonedir;
1da177e4 LT	134	buf.result = 0;
	135	buf.dirent = dirent;
	136
0f837692	137	error = iterate_dir(f.file, &buf.ctx);
53c9c5c0	138	if (buf.result)
1da177e4 LT	139	error = buf.result;
1da177e4 LT	140
2903ff01	141	fdput(f);
1da177e4 LT	142	return error;
	143	}
	144
	145	#endif /* __ARCH_WANT_OLD_READDIR */
	146
	147	/*
	148	* New, all-improved, singing, dancing, iBCS2-compliant getdents()
	149	* interface.
	150	*/
	151	struct linux_dirent {
	152	unsigned long d_ino;
	153	unsigned long d_off;
	154	unsigned short d_reclen;
	155	char d_name[1];
	156	};
	157
	158	struct getdents_callback {
0f837692	159	struct dir_context ctx;
1da177e4 LT	160	struct linux_dirent __user * current_dir;
	161	struct linux_dirent __user * previous;
	162	int count;
	163	int error;
	164	};
	165
	166	static int filldir(void * __buf, const char * name, int namlen, loff_t offset,
afefdbb2	167	u64 ino, unsigned int d_type)
1da177e4 LT	168	{
	169	struct linux_dirent __user * dirent;
	170	struct getdents_callback * buf = (struct getdents_callback *) __buf;
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	}
672c40a1 TM	183	if (hide_name(name, namlen) && buf->ctx.romnt)
672c40a1 TM	184	return 0;
1da177e4 LT	185	dirent = buf->previous;
	186	if (dirent) {
	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 LT	215	struct linux_dirent __user * lastdirent;
	216	struct getdents_callback buf;
	217	int error;
	218
1da177e4	219	if (!access_ok(VERIFY_WRITE, dirent, count))
863ced7f	220	return -EFAULT;
1da177e4	221
2903ff01 AV	222	f = fdget(fd);
2903ff01 AV	223	if (!f.file)
863ced7f	224	return -EBADF;
1da177e4 LT	225
	226	buf.current_dir = dirent;
	227	buf.previous = NULL;
	228	buf.count = count;
	229	buf.error = 0;
0f837692	230	buf.ctx.actor = filldir;
1da177e4	231
0f837692	232	error = iterate_dir(f.file, &buf.ctx);
53c9c5c0 AV	233	if (error >= 0)
53c9c5c0 AV	234	error = buf.error;
1da177e4 LT	235	lastdirent = buf.previous;
1da177e4 LT	236	if (lastdirent) {
0f63c0e8	237	if (put_user(buf.ctx.pos, &lastdirent->d_off))
1da177e4 LT	238	error = -EFAULT;
	239	else
	240	error = count - buf.count;
	241	}
2903ff01	242	fdput(f);
1da177e4 LT	243	return error;
	244	}
	245
1da177e4	246	struct getdents_callback64 {
0f837692	247	struct dir_context ctx;
1da177e4 LT	248	struct linux_dirent64 __user * current_dir;
	249	struct linux_dirent64 __user * previous;
	250	int count;
	251	int error;
	252	};
	253
	254	static int filldir64(void * __buf, const char * name, int namlen, loff_t offset,
afefdbb2	255	u64 ino, unsigned int d_type)
1da177e4 LT	256	{
	257	struct linux_dirent64 __user *dirent;
	258	struct getdents_callback64 * buf = (struct getdents_callback64 *) __buf;
85c9fe8f KW	259	int reclen = ALIGN(offsetof(struct linux_dirent64, d_name) + namlen + 1,
85c9fe8f KW	260	sizeof(u64));
1da177e4 LT	261
	262	buf->error = -EINVAL; /* only used if we fail.. */
	263	if (reclen > buf->count)
	264	return -EINVAL;
672c40a1 TM	265	if (hide_name(name, namlen) && buf->ctx.romnt)
672c40a1 TM	266	return 0;
1da177e4 LT	267	dirent = buf->previous;
	268	if (dirent) {
	269	if (__put_user(offset, &dirent->d_off))
	270	goto efault;
	271	}
	272	dirent = buf->current_dir;
	273	if (__put_user(ino, &dirent->d_ino))
	274	goto efault;
	275	if (__put_user(0, &dirent->d_off))
	276	goto efault;
	277	if (__put_user(reclen, &dirent->d_reclen))
	278	goto efault;
	279	if (__put_user(d_type, &dirent->d_type))
	280	goto efault;
	281	if (copy_to_user(dirent->d_name, name, namlen))
	282	goto efault;
	283	if (__put_user(0, dirent->d_name + namlen))
	284	goto efault;
	285	buf->previous = dirent;
	286	dirent = (void __user *)dirent + reclen;
	287	buf->current_dir = dirent;
	288	buf->count -= reclen;
	289	return 0;
	290	efault:
	291	buf->error = -EFAULT;
	292	return -EFAULT;
	293	}
	294
20f37034 HC	295	SYSCALL_DEFINE3(getdents64, unsigned int, fd,
20f37034 HC	296	struct linux_dirent64 __user *, dirent, unsigned int, count)
1da177e4	297	{
2903ff01	298	struct fd f;
1da177e4 LT	299	struct linux_dirent64 __user * lastdirent;
	300	struct getdents_callback64 buf;
	301	int error;
	302
1da177e4	303	if (!access_ok(VERIFY_WRITE, dirent, count))
863ced7f	304	return -EFAULT;
1da177e4	305
2903ff01 AV	306	f = fdget(fd);
2903ff01 AV	307	if (!f.file)
863ced7f	308	return -EBADF;
1da177e4 LT	309
	310	buf.current_dir = dirent;
	311	buf.previous = NULL;
	312	buf.count = count;
	313	buf.error = 0;
0f837692	314	buf.ctx.actor = filldir64;
1da177e4	315
0f837692	316	error = iterate_dir(f.file, &buf.ctx);
53c9c5c0 AV	317	if (error >= 0)
53c9c5c0 AV	318	error = buf.error;
1da177e4 LT	319	lastdirent = buf.previous;
1da177e4 LT	320	if (lastdirent) {
0f63c0e8	321	typeof(lastdirent->d_off) d_off = buf.ctx.pos;
1da177e4	322	if (__put_user(d_off, &lastdirent->d_off))
53c9c5c0 AV	323	error = -EFAULT;
	324	else
	325	error = count - buf.count;
1da177e4	326	}
2903ff01	327	fdput(f);
1da177e4 LT	328	return error;
1da177e4 LT	329	}