[mirror_ubuntu-bionic-kernel.git] / fs / sysv / namei.c

// SPDX-License-Identifier: GPL-2.0
/*
 *  linux/fs/sysv/namei.c
 *
 *  minix/namei.c
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 *  coh/namei.c
 *  Copyright (C) 1993  Pascal Haible, Bruno Haible
 *
 *  sysv/namei.c
 *  Copyright (C) 1993  Bruno Haible
 *  Copyright (C) 1997, 1998  Krzysztof G. Baranowski
 */

#include <linux/pagemap.h>
#include "sysv.h"

static int add_nondir(struct dentry *dentry, struct inode *inode)
{
	int err = sysv_add_link(dentry, inode);
	if (!err) {
		d_instantiate(dentry, inode);
		return 0;
	}
	inode_dec_link_count(inode);
	iput(inode);
	return err;
}

static int sysv_hash(const struct dentry *dentry, struct qstr *qstr)
{
	/* Truncate the name in place, avoids having to define a compare
	   function. */
	if (qstr->len > SYSV_NAMELEN) {
		qstr->len = SYSV_NAMELEN;
		qstr->hash = full_name_hash(dentry, qstr->name, qstr->len);
	}
	return 0;
}

const struct dentry_operations sysv_dentry_operations = {
	.d_hash		= sysv_hash,
};

static struct dentry *sysv_lookup(struct inode * dir, struct dentry * dentry, unsigned int flags)
{
	struct inode * inode = NULL;
	ino_t ino;

	if (dentry->d_name.len > SYSV_NAMELEN)
		return ERR_PTR(-ENAMETOOLONG);
	ino = sysv_inode_by_name(dentry);

	if (ino) {
		inode = sysv_iget(dir->i_sb, ino);
		if (IS_ERR(inode))
			return ERR_CAST(inode);
	}
	d_add(dentry, inode);
	return NULL;
}

static int sysv_mknod(struct inode * dir, struct dentry * dentry, umode_t mode, dev_t rdev)
{
	struct inode * inode;
	int err;

	if (!old_valid_dev(rdev))
		return -EINVAL;

	inode = sysv_new_inode(dir, mode);
	err = PTR_ERR(inode);

	if (!IS_ERR(inode)) {
		sysv_set_inode(inode, rdev);
		mark_inode_dirty(inode);
		err = add_nondir(dentry, inode);
	}
	return err;
}

static int sysv_create(struct inode * dir, struct dentry * dentry, umode_t mode, bool excl)
{
	return sysv_mknod(dir, dentry, mode, 0);
}

static int sysv_symlink(struct inode * dir, struct dentry * dentry, 
	const char * symname)
{
	int err = -ENAMETOOLONG;
	int l = strlen(symname)+1;
	struct inode * inode;

	if (l > dir->i_sb->s_blocksize)
		goto out;

	inode = sysv_new_inode(dir, S_IFLNK|0777);
	err = PTR_ERR(inode);
	if (IS_ERR(inode))
		goto out;
	
	sysv_set_inode(inode, 0);
	err = page_symlink(inode, symname, l);
	if (err)
		goto out_fail;

	mark_inode_dirty(inode);
	err = add_nondir(dentry, inode);
out:
	return err;

out_fail:
	inode_dec_link_count(inode);
	iput(inode);
	goto out;
}

static int sysv_link(struct dentry * old_dentry, struct inode * dir, 
	struct dentry * dentry)
{
	struct inode *inode = d_inode(old_dentry);

	inode->i_ctime = current_time(inode);
	inode_inc_link_count(inode);
	ihold(inode);

	return add_nondir(dentry, inode);
}

static int sysv_mkdir(struct inode * dir, struct dentry *dentry, umode_t mode)
{
	struct inode * inode;
	int err;

	inode_inc_link_count(dir);

	inode = sysv_new_inode(dir, S_IFDIR|mode);
	err = PTR_ERR(inode);
	if (IS_ERR(inode))
		goto out_dir;

	sysv_set_inode(inode, 0);

	inode_inc_link_count(inode);

	err = sysv_make_empty(inode, dir);
	if (err)
		goto out_fail;

	err = sysv_add_link(dentry, inode);
	if (err)
		goto out_fail;

        d_instantiate(dentry, inode);
out:
	return err;

out_fail:
	inode_dec_link_count(inode);
	inode_dec_link_count(inode);
	iput(inode);
out_dir:
	inode_dec_link_count(dir);
	goto out;
}

static int sysv_unlink(struct inode * dir, struct dentry * dentry)
{
	struct inode * inode = d_inode(dentry);
	struct page * page;
	struct sysv_dir_entry * de;
	int err = -ENOENT;

	de = sysv_find_entry(dentry, &page);
	if (!de)
		goto out;

	err = sysv_delete_entry (de, page);
	if (err)
		goto out;

	inode->i_ctime = dir->i_ctime;
	inode_dec_link_count(inode);
out:
	return err;
}

static int sysv_rmdir(struct inode * dir, struct dentry * dentry)
{
	struct inode *inode = d_inode(dentry);
	int err = -ENOTEMPTY;

	if (sysv_empty_dir(inode)) {
		err = sysv_unlink(dir, dentry);
		if (!err) {
			inode->i_size = 0;
			inode_dec_link_count(inode);
			inode_dec_link_count(dir);
		}
	}
	return err;
}

/*
 * Anybody can rename anything with this: the permission checks are left to the
 * higher-level routines.
 */
static int sysv_rename(struct inode * old_dir, struct dentry * old_dentry,
		       struct inode * new_dir, struct dentry * new_dentry,
		       unsigned int flags)
{
	struct inode * old_inode = d_inode(old_dentry);
	struct inode * new_inode = d_inode(new_dentry);
	struct page * dir_page = NULL;
	struct sysv_dir_entry * dir_de = NULL;
	struct page * old_page;
	struct sysv_dir_entry * old_de;
	int err = -ENOENT;

	if (flags & ~RENAME_NOREPLACE)
		return -EINVAL;

	old_de = sysv_find_entry(old_dentry, &old_page);
	if (!old_de)
		goto out;

	if (S_ISDIR(old_inode->i_mode)) {
		err = -EIO;
		dir_de = sysv_dotdot(old_inode, &dir_page);
		if (!dir_de)
			goto out_old;
	}

	if (new_inode) {
		struct page * new_page;
		struct sysv_dir_entry * new_de;

		err = -ENOTEMPTY;
		if (dir_de && !sysv_empty_dir(new_inode))
			goto out_dir;

		err = -ENOENT;
		new_de = sysv_find_entry(new_dentry, &new_page);
		if (!new_de)
			goto out_dir;
		sysv_set_link(new_de, new_page, old_inode);
		new_inode->i_ctime = current_time(new_inode);
		if (dir_de)
			drop_nlink(new_inode);
		inode_dec_link_count(new_inode);
	} else {
		err = sysv_add_link(new_dentry, old_inode);
		if (err)
			goto out_dir;
		if (dir_de)
			inode_inc_link_count(new_dir);
	}

	sysv_delete_entry(old_de, old_page);
	mark_inode_dirty(old_inode);

	if (dir_de) {
		sysv_set_link(dir_de, dir_page, new_dir);
		inode_dec_link_count(old_dir);
	}
	return 0;

out_dir:
	if (dir_de) {
		kunmap(dir_page);
		put_page(dir_page);
	}
out_old:
	kunmap(old_page);
	put_page(old_page);
out:
	return err;
}

/*
 * directories can handle most operations...
 */
const struct inode_operations sysv_dir_inode_operations = {
	.create		= sysv_create,
	.lookup		= sysv_lookup,
	.link		= sysv_link,
	.unlink		= sysv_unlink,
	.symlink	= sysv_symlink,
	.mkdir		= sysv_mkdir,
	.rmdir		= sysv_rmdir,
	.mknod		= sysv_mknod,
	.rename		= sysv_rename,
	.getattr	= sysv_getattr,
};
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
1da177e4 LT	2	/*
	3	* linux/fs/sysv/namei.c
	4	*
	5	* minix/namei.c
	6	* Copyright (C) 1991, 1992 Linus Torvalds
	7	*
	8	* coh/namei.c
	9	* Copyright (C) 1993 Pascal Haible, Bruno Haible
	10	*
	11	* sysv/namei.c
	12	* Copyright (C) 1993 Bruno Haible
	13	* Copyright (C) 1997, 1998 Krzysztof G. Baranowski
	14	*/
	15
	16	#include <linux/pagemap.h>
1da177e4 LT	17	#include "sysv.h"
1da177e4 LT	18
1da177e4 LT	19	static int add_nondir(struct dentry dentry, struct inode inode)
	20	{
	21	int err = sysv_add_link(dentry, inode);
	22	if (!err) {
	23	d_instantiate(dentry, inode);
	24	return 0;
	25	}
4e907c3d	26	inode_dec_link_count(inode);
1da177e4 LT	27	iput(inode);
	28	return err;
	29	}
	30
da53be12	31	static int sysv_hash(const struct dentry dentry, struct qstr qstr)
1da177e4 LT	32	{
	33	/* Truncate the name in place, avoids having to define a compare
	34	function. */
	35	if (qstr->len > SYSV_NAMELEN) {
	36	qstr->len = SYSV_NAMELEN;
8387ff25	37	qstr->hash = full_name_hash(dentry, qstr->name, qstr->len);
1da177e4 LT	38	}
	39	return 0;
	40	}
	41
e16404ed	42	const struct dentry_operations sysv_dentry_operations = {
1da177e4 LT	43	.d_hash = sysv_hash,
	44	};
	45
00cd8dd3	46	static struct dentry sysv_lookup(struct inode dir, struct dentry * dentry, unsigned int flags)
1da177e4 LT	47	{
	48	struct inode * inode = NULL;
	49	ino_t ino;
	50
1da177e4 LT	51	if (dentry->d_name.len > SYSV_NAMELEN)
	52	return ERR_PTR(-ENAMETOOLONG);
	53	ino = sysv_inode_by_name(dentry);
	54
	55	if (ino) {
b8e1343f DH	56	inode = sysv_iget(dir->i_sb, ino);
	57	if (IS_ERR(inode))
	58	return ERR_CAST(inode);
1da177e4 LT	59	}
	60	d_add(dentry, inode);
	61	return NULL;
	62	}
	63
1a67aafb	64	static int sysv_mknod(struct inode * dir, struct dentry * dentry, umode_t mode, dev_t rdev)
1da177e4 LT	65	{
	66	struct inode * inode;
	67	int err;
	68
	69	if (!old_valid_dev(rdev))
	70	return -EINVAL;
	71
	72	inode = sysv_new_inode(dir, mode);
	73	err = PTR_ERR(inode);
	74
	75	if (!IS_ERR(inode)) {
	76	sysv_set_inode(inode, rdev);
	77	mark_inode_dirty(inode);
	78	err = add_nondir(dentry, inode);
	79	}
	80	return err;
	81	}
	82
ebfc3b49	83	static int sysv_create(struct inode * dir, struct dentry * dentry, umode_t mode, bool excl)
1da177e4 LT	84	{
	85	return sysv_mknod(dir, dentry, mode, 0);
	86	}
	87
	88	static int sysv_symlink(struct inode * dir, struct dentry * dentry,
	89	const char * symname)
	90	{
	91	int err = -ENAMETOOLONG;
	92	int l = strlen(symname)+1;
	93	struct inode * inode;
	94
	95	if (l > dir->i_sb->s_blocksize)
	96	goto out;
	97
	98	inode = sysv_new_inode(dir, S_IFLNK\|0777);
	99	err = PTR_ERR(inode);
	100	if (IS_ERR(inode))
	101	goto out;
	102
	103	sysv_set_inode(inode, 0);
	104	err = page_symlink(inode, symname, l);
	105	if (err)
	106	goto out_fail;
	107
	108	mark_inode_dirty(inode);
	109	err = add_nondir(dentry, inode);
	110	out:
	111	return err;
	112
	113	out_fail:
4e907c3d	114	inode_dec_link_count(inode);
1da177e4 LT	115	iput(inode);
	116	goto out;
	117	}
	118
	119	static int sysv_link(struct dentry * old_dentry, struct inode * dir,
	120	struct dentry * dentry)
	121	{
2b0143b5	122	struct inode *inode = d_inode(old_dentry);
1da177e4	123
02027d42	124	inode->i_ctime = current_time(inode);
4e907c3d	125	inode_inc_link_count(inode);
7de9c6ee	126	ihold(inode);
1da177e4 LT	127
	128	return add_nondir(dentry, inode);
	129	}
	130
18bb1db3	131	static int sysv_mkdir(struct inode * dir, struct dentry *dentry, umode_t mode)
1da177e4 LT	132	{
1da177e4 LT	133	struct inode * inode;
8de52778	134	int err;
1da177e4	135
4e907c3d	136	inode_inc_link_count(dir);
1da177e4 LT	137
	138	inode = sysv_new_inode(dir, S_IFDIR\|mode);
	139	err = PTR_ERR(inode);
	140	if (IS_ERR(inode))
	141	goto out_dir;
	142
	143	sysv_set_inode(inode, 0);
	144
4e907c3d	145	inode_inc_link_count(inode);
1da177e4 LT	146
	147	err = sysv_make_empty(inode, dir);
	148	if (err)
	149	goto out_fail;
	150
	151	err = sysv_add_link(dentry, inode);
	152	if (err)
	153	goto out_fail;
	154
	155	d_instantiate(dentry, inode);
	156	out:
	157	return err;
	158
	159	out_fail:
4e907c3d AD	160	inode_dec_link_count(inode);
4e907c3d AD	161	inode_dec_link_count(inode);
1da177e4 LT	162	iput(inode);
1da177e4 LT	163	out_dir:
4e907c3d	164	inode_dec_link_count(dir);
1da177e4 LT	165	goto out;
	166	}
	167
	168	static int sysv_unlink(struct inode * dir, struct dentry * dentry)
	169	{
2b0143b5	170	struct inode * inode = d_inode(dentry);
1da177e4 LT	171	struct page * page;
	172	struct sysv_dir_entry * de;
	173	int err = -ENOENT;
	174
	175	de = sysv_find_entry(dentry, &page);
	176	if (!de)
	177	goto out;
	178
	179	err = sysv_delete_entry (de, page);
	180	if (err)
	181	goto out;
	182
	183	inode->i_ctime = dir->i_ctime;
4e907c3d	184	inode_dec_link_count(inode);
1da177e4 LT	185	out:
	186	return err;
	187	}
	188
	189	static int sysv_rmdir(struct inode * dir, struct dentry * dentry)
	190	{
2b0143b5	191	struct inode *inode = d_inode(dentry);
1da177e4 LT	192	int err = -ENOTEMPTY;
	193
	194	if (sysv_empty_dir(inode)) {
	195	err = sysv_unlink(dir, dentry);
	196	if (!err) {
	197	inode->i_size = 0;
4e907c3d AD	198	inode_dec_link_count(inode);
4e907c3d AD	199	inode_dec_link_count(dir);
1da177e4 LT	200	}
	201	}
	202	return err;
	203	}
	204
	205	/*
	206	* Anybody can rename anything with this: the permission checks are left to the
	207	* higher-level routines.
	208	*/
	209	static int sysv_rename(struct inode * old_dir, struct dentry * old_dentry,
f03b8ad8 MS	210	struct inode * new_dir, struct dentry * new_dentry,
f03b8ad8 MS	211	unsigned int flags)
1da177e4	212	{
2b0143b5 DH	213	struct inode * old_inode = d_inode(old_dentry);
2b0143b5 DH	214	struct inode * new_inode = d_inode(new_dentry);
1da177e4 LT	215	struct page * dir_page = NULL;
	216	struct sysv_dir_entry * dir_de = NULL;
	217	struct page * old_page;
	218	struct sysv_dir_entry * old_de;
	219	int err = -ENOENT;
	220
f03b8ad8 MS	221	if (flags & ~RENAME_NOREPLACE)
	222	return -EINVAL;
	223
1da177e4 LT	224	old_de = sysv_find_entry(old_dentry, &old_page);
	225	if (!old_de)
	226	goto out;
	227
	228	if (S_ISDIR(old_inode->i_mode)) {
	229	err = -EIO;
	230	dir_de = sysv_dotdot(old_inode, &dir_page);
	231	if (!dir_de)
	232	goto out_old;
	233	}
	234
	235	if (new_inode) {
	236	struct page * new_page;
	237	struct sysv_dir_entry * new_de;
	238
	239	err = -ENOTEMPTY;
	240	if (dir_de && !sysv_empty_dir(new_inode))
	241	goto out_dir;
	242
	243	err = -ENOENT;
	244	new_de = sysv_find_entry(new_dentry, &new_page);
	245	if (!new_de)
	246	goto out_dir;
1da177e4	247	sysv_set_link(new_de, new_page, old_inode);
02027d42	248	new_inode->i_ctime = current_time(new_inode);
1da177e4	249	if (dir_de)
9a53c3a7	250	drop_nlink(new_inode);
4e907c3d	251	inode_dec_link_count(new_inode);
1da177e4	252	} else {
1da177e4	253	err = sysv_add_link(new_dentry, old_inode);
4787d45f	254	if (err)
1da177e4	255	goto out_dir;
1da177e4	256	if (dir_de)
4e907c3d	257	inode_inc_link_count(new_dir);
1da177e4 LT	258	}
	259
	260	sysv_delete_entry(old_de, old_page);
4787d45f	261	mark_inode_dirty(old_inode);
1da177e4 LT	262
	263	if (dir_de) {
	264	sysv_set_link(dir_de, dir_page, new_dir);
4e907c3d	265	inode_dec_link_count(old_dir);
1da177e4 LT	266	}
	267	return 0;
	268
	269	out_dir:
	270	if (dir_de) {
	271	kunmap(dir_page);
09cbfeaf	272	put_page(dir_page);
1da177e4 LT	273	}
	274	out_old:
	275	kunmap(old_page);
09cbfeaf	276	put_page(old_page);
1da177e4 LT	277	out:
	278	return err;
	279	}
	280
	281	/*
	282	* directories can handle most operations...
	283	*/
c5ef1c42	284	const struct inode_operations sysv_dir_inode_operations = {
1da177e4 LT	285	.create = sysv_create,
	286	.lookup = sysv_lookup,
	287	.link = sysv_link,
	288	.unlink = sysv_unlink,
	289	.symlink = sysv_symlink,
	290	.mkdir = sysv_mkdir,
	291	.rmdir = sysv_rmdir,
	292	.mknod = sysv_mknod,
	293	.rename = sysv_rename,
	294	.getattr = sysv_getattr,
	295	};