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(error: -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(dev: rdev)) |
51 | return -EINVAL; |
52 | |
53 | inode = sysv_new_inode(dir, mode); |
54 | err = PTR_ERR(ptr: inode); |
55 | |
56 | if (!IS_ERR(ptr: 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(idmap: &nop_mnt_idmap, dir, dentry, mode, rdev: 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(ptr: inode); |
82 | if (IS_ERR(ptr: inode)) |
83 | goto out; |
84 | |
85 | sysv_set_inode(inode, 0); |
86 | err = page_symlink(inode, symname, len: 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(dentry: 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(inode: dir); |
120 | |
121 | inode = sysv_new_inode(dir, S_IFDIR|mode); |
122 | err = PTR_ERR(ptr: inode); |
123 | if (IS_ERR(ptr: 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(inode: 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, ts: inode_get_ctime(inode: dir)); |
165 | inode_dec_link_count(inode); |
166 | } |
167 | unmap_and_put_page(page, addr: 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(inode: 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(dentry: old_dentry); |
196 | struct inode * new_inode = d_inode(dentry: 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(page: new_page, addr: new_de); |
231 | if (err) |
232 | goto out_dir; |
233 | inode_set_ctime_current(inode: new_inode); |
234 | if (dir_de) |
235 | drop_nlink(inode: new_inode); |
236 | inode_dec_link_count(inode: 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(inode: 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(inode: 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(inode: old_dir); |
255 | } |
256 | |
257 | out_dir: |
258 | if (dir_de) |
259 | unmap_and_put_page(page: dir_page, addr: dir_de); |
260 | out_old: |
261 | unmap_and_put_page(page: old_page, addr: 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 | |