1 // SPDX-License-Identifier: GPL-2.0
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>
17 #include "sysv.h"
18
add_nondir(struct dentry * dentry,struct inode * inode)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 }
26 inode_dec_link_count(inode);
27 iput(inode);
28 return err;
29 }
30
sysv_lookup(struct inode * dir,struct dentry * dentry,unsigned int flags)31 static struct dentry *sysv_lookup(struct inode * dir, struct dentry * dentry, unsigned int flags)
32 {
33 struct inode * inode = NULL;
34 ino_t ino;
35
36 if (dentry->d_name.len > SYSV_NAMELEN)
37 return ERR_PTR(-ENAMETOOLONG);
38 ino = sysv_inode_by_name(dentry);
39 if (ino)
40 inode = sysv_iget(dir->i_sb, ino);
41 return d_splice_alias(inode, dentry);
42 }
43
sysv_mknod(struct inode * dir,struct dentry * dentry,umode_t mode,dev_t rdev)44 static int sysv_mknod(struct inode * dir, struct dentry * dentry, umode_t mode, dev_t rdev)
45 {
46 struct inode * inode;
47 int err;
48
49 if (!old_valid_dev(rdev))
50 return -EINVAL;
51
52 inode = sysv_new_inode(dir, mode);
53 err = PTR_ERR(inode);
54
55 if (!IS_ERR(inode)) {
56 sysv_set_inode(inode, rdev);
57 mark_inode_dirty(inode);
58 err = add_nondir(dentry, inode);
59 }
60 return err;
61 }
62
sysv_create(struct inode * dir,struct dentry * dentry,umode_t mode,bool excl)63 static int sysv_create(struct inode * dir, struct dentry * dentry, umode_t mode, bool excl)
64 {
65 return sysv_mknod(dir, dentry, mode, 0);
66 }
67
sysv_symlink(struct inode * dir,struct dentry * dentry,const char * symname)68 static int sysv_symlink(struct inode * dir, struct dentry * dentry,
69 const char * symname)
70 {
71 int err = -ENAMETOOLONG;
72 int l = strlen(symname)+1;
73 struct inode * inode;
74
75 if (l > dir->i_sb->s_blocksize)
76 goto out;
77
78 inode = sysv_new_inode(dir, S_IFLNK|0777);
79 err = PTR_ERR(inode);
80 if (IS_ERR(inode))
81 goto out;
82
83 sysv_set_inode(inode, 0);
84 err = page_symlink(inode, symname, l);
85 if (err)
86 goto out_fail;
87
88 mark_inode_dirty(inode);
89 err = add_nondir(dentry, inode);
90 out:
91 return err;
92
93 out_fail:
94 inode_dec_link_count(inode);
95 iput(inode);
96 goto out;
97 }
98
sysv_link(struct dentry * old_dentry,struct inode * dir,struct dentry * dentry)99 static int sysv_link(struct dentry * old_dentry, struct inode * dir,
100 struct dentry * dentry)
101 {
102 struct inode *inode = d_inode(old_dentry);
103
104 inode->i_ctime = current_time(inode);
105 inode_inc_link_count(inode);
106 ihold(inode);
107
108 return add_nondir(dentry, inode);
109 }
110
sysv_mkdir(struct inode * dir,struct dentry * dentry,umode_t mode)111 static int sysv_mkdir(struct inode * dir, struct dentry *dentry, umode_t mode)
112 {
113 struct inode * inode;
114 int err;
115
116 inode_inc_link_count(dir);
117
118 inode = sysv_new_inode(dir, S_IFDIR|mode);
119 err = PTR_ERR(inode);
120 if (IS_ERR(inode))
121 goto out_dir;
122
123 sysv_set_inode(inode, 0);
124
125 inode_inc_link_count(inode);
126
127 err = sysv_make_empty(inode, dir);
128 if (err)
129 goto out_fail;
130
131 err = sysv_add_link(dentry, inode);
132 if (err)
133 goto out_fail;
134
135 d_instantiate(dentry, inode);
136 out:
137 return err;
138
139 out_fail:
140 inode_dec_link_count(inode);
141 inode_dec_link_count(inode);
142 iput(inode);
143 out_dir:
144 inode_dec_link_count(dir);
145 goto out;
146 }
147
sysv_unlink(struct inode * dir,struct dentry * dentry)148 static int sysv_unlink(struct inode * dir, struct dentry * dentry)
149 {
150 struct inode * inode = d_inode(dentry);
151 struct page * page;
152 struct sysv_dir_entry * de;
153 int err = -ENOENT;
154
155 de = sysv_find_entry(dentry, &page);
156 if (!de)
157 goto out;
158
159 err = sysv_delete_entry (de, page);
160 if (err)
161 goto out;
162
163 inode->i_ctime = dir->i_ctime;
164 inode_dec_link_count(inode);
165 out:
166 return err;
167 }
168
sysv_rmdir(struct inode * dir,struct dentry * dentry)169 static int sysv_rmdir(struct inode * dir, struct dentry * dentry)
170 {
171 struct inode *inode = d_inode(dentry);
172 int err = -ENOTEMPTY;
173
174 if (sysv_empty_dir(inode)) {
175 err = sysv_unlink(dir, dentry);
176 if (!err) {
177 inode->i_size = 0;
178 inode_dec_link_count(inode);
179 inode_dec_link_count(dir);
180 }
181 }
182 return err;
183 }
184
185 /*
186 * Anybody can rename anything with this: the permission checks are left to the
187 * higher-level routines.
188 */
sysv_rename(struct inode * old_dir,struct dentry * old_dentry,struct inode * new_dir,struct dentry * new_dentry,unsigned int flags)189 static int sysv_rename(struct inode * old_dir, struct dentry * old_dentry,
190 struct inode * new_dir, struct dentry * new_dentry,
191 unsigned int flags)
192 {
193 struct inode * old_inode = d_inode(old_dentry);
194 struct inode * new_inode = d_inode(new_dentry);
195 struct page * dir_page = NULL;
196 struct sysv_dir_entry * dir_de = NULL;
197 struct page * old_page;
198 struct sysv_dir_entry * old_de;
199 int err = -ENOENT;
200
201 if (flags & ~RENAME_NOREPLACE)
202 return -EINVAL;
203
204 old_de = sysv_find_entry(old_dentry, &old_page);
205 if (!old_de)
206 goto out;
207
208 if (S_ISDIR(old_inode->i_mode)) {
209 err = -EIO;
210 dir_de = sysv_dotdot(old_inode, &dir_page);
211 if (!dir_de)
212 goto out_old;
213 }
214
215 if (new_inode) {
216 struct page * new_page;
217 struct sysv_dir_entry * new_de;
218
219 err = -ENOTEMPTY;
220 if (dir_de && !sysv_empty_dir(new_inode))
221 goto out_dir;
222
223 err = -ENOENT;
224 new_de = sysv_find_entry(new_dentry, &new_page);
225 if (!new_de)
226 goto out_dir;
227 sysv_set_link(new_de, new_page, old_inode);
228 new_inode->i_ctime = current_time(new_inode);
229 if (dir_de)
230 drop_nlink(new_inode);
231 inode_dec_link_count(new_inode);
232 } else {
233 err = sysv_add_link(new_dentry, old_inode);
234 if (err)
235 goto out_dir;
236 if (dir_de)
237 inode_inc_link_count(new_dir);
238 }
239
240 sysv_delete_entry(old_de, old_page);
241 mark_inode_dirty(old_inode);
242
243 if (dir_de) {
244 sysv_set_link(dir_de, dir_page, new_dir);
245 inode_dec_link_count(old_dir);
246 }
247 return 0;
248
249 out_dir:
250 if (dir_de) {
251 kunmap(dir_page);
252 put_page(dir_page);
253 }
254 out_old:
255 kunmap(old_page);
256 put_page(old_page);
257 out:
258 return err;
259 }
260
261 /*
262 * directories can handle most operations...
263 */
264 const struct inode_operations sysv_dir_inode_operations = {
265 .create = sysv_create,
266 .lookup = sysv_lookup,
267 .link = sysv_link,
268 .unlink = sysv_unlink,
269 .symlink = sysv_symlink,
270 .mkdir = sysv_mkdir,
271 .rmdir = sysv_rmdir,
272 .mknod = sysv_mknod,
273 .rename = sysv_rename,
274 .getattr = sysv_getattr,
275 };
276