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
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
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
44 static int sysv_mknod(struct mnt_idmap *idmap, struct inode *dir,
45 struct dentry *dentry, umode_t mode, dev_t rdev)
46 {
47 struct inode * inode;
48 int err;
49
50 if (!old_valid_dev(rdev))
51 return -EINVAL;
52
53 inode = sysv_new_inode(dir, mode);
54 err = PTR_ERR(inode);
55
56 if (!IS_ERR(inode)) {
57 sysv_set_inode(inode, rdev);
58 mark_inode_dirty(inode);
59 err = add_nondir(dentry, inode);
60 }
61 return err;
62 }
63
64 static int sysv_create(struct mnt_idmap *idmap, struct inode *dir,
65 struct dentry *dentry, umode_t mode, bool excl)
66 {
67 return sysv_mknod(&nop_mnt_idmap, dir, dentry, mode, 0);
68 }
69
70 static int sysv_symlink(struct mnt_idmap *idmap, struct inode *dir,
71 struct dentry *dentry, const char *symname)
72 {
73 int err = -ENAMETOOLONG;
74 int l = strlen(symname)+1;
75 struct inode * inode;
76
77 if (l > dir->i_sb->s_blocksize)
78 goto out;
79
80 inode = sysv_new_inode(dir, S_IFLNK|0777);
81 err = PTR_ERR(inode);
82 if (IS_ERR(inode))
83 goto out;
84
85 sysv_set_inode(inode, 0);
86 err = page_symlink(inode, symname, l);
87 if (err)
88 goto out_fail;
89
90 mark_inode_dirty(inode);
91 err = add_nondir(dentry, inode);
92 out:
93 return err;
94
95 out_fail:
96 inode_dec_link_count(inode);
97 iput(inode);
98 goto out;
99 }
100
101 static int sysv_link(struct dentry * old_dentry, struct inode * dir,
102 struct dentry * dentry)
103 {
104 struct inode *inode = d_inode(old_dentry);
105
106 inode_set_ctime_current(inode);
107 inode_inc_link_count(inode);
108 ihold(inode);
109
110 return add_nondir(dentry, inode);
111 }
112
113 static int sysv_mkdir(struct mnt_idmap *idmap, struct inode *dir,
114 struct dentry *dentry, umode_t mode)
115 {
116 struct inode * inode;
117 int err;
118
119 inode_inc_link_count(dir);
120
121 inode = sysv_new_inode(dir, S_IFDIR|mode);
122 err = PTR_ERR(inode);
123 if (IS_ERR(inode))
124 goto out_dir;
125
126 sysv_set_inode(inode, 0);
127
128 inode_inc_link_count(inode);
129
130 err = sysv_make_empty(inode, dir);
131 if (err)
132 goto out_fail;
133
134 err = sysv_add_link(dentry, inode);
135 if (err)
136 goto out_fail;
137
138 d_instantiate(dentry, inode);
139 out:
140 return err;
141
142 out_fail:
143 inode_dec_link_count(inode);
144 inode_dec_link_count(inode);
145 iput(inode);
146 out_dir:
147 inode_dec_link_count(dir);
148 goto out;
149 }
150
151 static int sysv_unlink(struct inode * dir, struct dentry * dentry)
152 {
153 struct inode * inode = d_inode(dentry);
154 struct page * page;
155 struct sysv_dir_entry * de;
156 int err;
157
158 de = sysv_find_entry(dentry, &page);
159 if (!de)
160 return -ENOENT;
161
162 err = sysv_delete_entry(de, page);
163 if (!err) {
164 inode_set_ctime_to_ts(inode, inode_get_ctime(dir));
165 inode_dec_link_count(inode);
166 }
167 unmap_and_put_page(page, de);
168 return err;
169 }
170
171 static int sysv_rmdir(struct inode * dir, struct dentry * dentry)
172 {
173 struct inode *inode = d_inode(dentry);
174 int err = -ENOTEMPTY;
175
176 if (sysv_empty_dir(inode)) {
177 err = sysv_unlink(dir, dentry);
178 if (!err) {
179 inode->i_size = 0;
180 inode_dec_link_count(inode);
181 inode_dec_link_count(dir);
182 }
183 }
184 return err;
185 }
186
187 /*
188 * Anybody can rename anything with this: the permission checks are left to the
189 * higher-level routines.
190 */
191 static int sysv_rename(struct mnt_idmap *idmap, struct inode *old_dir,
192 struct dentry *old_dentry, struct inode *new_dir,
193 struct dentry *new_dentry, unsigned int flags)
194 {
195 struct inode * old_inode = d_inode(old_dentry);
196 struct inode * new_inode = d_inode(new_dentry);
197 struct page * dir_page = NULL;
198 struct sysv_dir_entry * dir_de = NULL;
199 struct page * old_page;
200 struct sysv_dir_entry * old_de;
201 int err = -ENOENT;
202
203 if (flags & ~RENAME_NOREPLACE)
204 return -EINVAL;
205
206 old_de = sysv_find_entry(old_dentry, &old_page);
207 if (!old_de)
208 goto out;
209
210 if (S_ISDIR(old_inode->i_mode)) {
211 err = -EIO;
212 dir_de = sysv_dotdot(old_inode, &dir_page);
213 if (!dir_de)
214 goto out_old;
215 }
216
217 if (new_inode) {
218 struct page * new_page;
219 struct sysv_dir_entry * new_de;
220
221 err = -ENOTEMPTY;
222 if (dir_de && !sysv_empty_dir(new_inode))
223 goto out_dir;
224
225 err = -ENOENT;
226 new_de = sysv_find_entry(new_dentry, &new_page);
227 if (!new_de)
228 goto out_dir;
229 err = sysv_set_link(new_de, new_page, old_inode);
230 unmap_and_put_page(new_page, new_de);
231 if (err)
232 goto out_dir;
233 inode_set_ctime_current(new_inode);
234 if (dir_de)
235 drop_nlink(new_inode);
236 inode_dec_link_count(new_inode);
237 } else {
238 err = sysv_add_link(new_dentry, old_inode);
239 if (err)
240 goto out_dir;
241 if (dir_de)
242 inode_inc_link_count(new_dir);
243 }
244
245 err = sysv_delete_entry(old_de, old_page);
246 if (err)
247 goto out_dir;
248
249 mark_inode_dirty(old_inode);
250
251 if (dir_de) {
252 err = sysv_set_link(dir_de, dir_page, new_dir);
253 if (!err)
254 inode_dec_link_count(old_dir);
255 }
256
257 out_dir:
258 if (dir_de)
259 unmap_and_put_page(dir_page, dir_de);
260 out_old:
261 unmap_and_put_page(old_page, old_de);
262 out:
263 return err;
264 }
265
266 /*
267 * directories can handle most operations...
268 */
269 const struct inode_operations sysv_dir_inode_operations = {
270 .create = sysv_create,
271 .lookup = sysv_lookup,
272 .link = sysv_link,
273 .unlink = sysv_unlink,
274 .symlink = sysv_symlink,
275 .mkdir = sysv_mkdir,
276 .rmdir = sysv_rmdir,
277 .mknod = sysv_mknod,
278 .rename = sysv_rename,
279 .getattr = sysv_getattr,
280 };
281
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.