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 int sysv_hash(const struct dentry *dentry, struct qstr *qstr) 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; 37 qstr->hash = full_name_hash(dentry, qstr->name, qstr->len); 38 } 39 return 0; 40 } 41 42 const struct dentry_operations sysv_dentry_operations = { 43 .d_hash = sysv_hash, 44 }; 45 46 static struct dentry *sysv_lookup(struct inode * dir, struct dentry * dentry, unsigned int flags) 47 { 48 struct inode * inode = NULL; 49 ino_t ino; 50 51 if (dentry->d_name.len > SYSV_NAMELEN) 52 return ERR_PTR(-ENAMETOOLONG); 53 ino = sysv_inode_by_name(dentry); 54 55 if (ino) { 56 inode = sysv_iget(dir->i_sb, ino); 57 if (IS_ERR(inode)) 58 return ERR_CAST(inode); 59 } 60 d_add(dentry, inode); 61 return NULL; 62 } 63 64 static int sysv_mknod(struct inode * dir, struct dentry * dentry, umode_t mode, dev_t rdev) 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 83 static int sysv_create(struct inode * dir, struct dentry * dentry, umode_t mode, bool excl) 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: 114 inode_dec_link_count(inode); 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 { 122 struct inode *inode = d_inode(old_dentry); 123 124 inode->i_ctime = current_time(inode); 125 inode_inc_link_count(inode); 126 ihold(inode); 127 128 return add_nondir(dentry, inode); 129 } 130 131 static int sysv_mkdir(struct inode * dir, struct dentry *dentry, umode_t mode) 132 { 133 struct inode * inode; 134 int err; 135 136 inode_inc_link_count(dir); 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); 144 145 inode_inc_link_count(inode); 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: 160 inode_dec_link_count(inode); 161 inode_dec_link_count(inode); 162 iput(inode); 163 out_dir: 164 inode_dec_link_count(dir); 165 goto out; 166 } 167 168 static int sysv_unlink(struct inode * dir, struct dentry * dentry) 169 { 170 struct inode * inode = d_inode(dentry); 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; 184 inode_dec_link_count(inode); 185 out: 186 return err; 187 } 188 189 static int sysv_rmdir(struct inode * dir, struct dentry * dentry) 190 { 191 struct inode *inode = d_inode(dentry); 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; 198 inode_dec_link_count(inode); 199 inode_dec_link_count(dir); 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, 210 struct inode * new_dir, struct dentry * new_dentry, 211 unsigned int flags) 212 { 213 struct inode * old_inode = d_inode(old_dentry); 214 struct inode * new_inode = d_inode(new_dentry); 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; 220 221 if (flags & ~RENAME_NOREPLACE) 222 return -EINVAL; 223 224 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; 247 sysv_set_link(new_de, new_page, old_inode); 248 new_inode->i_ctime = current_time(new_inode); 249 if (dir_de) 250 drop_nlink(new_inode); 251 inode_dec_link_count(new_inode); 252 } else { 253 err = sysv_add_link(new_dentry, old_inode); 254 if (err) 255 goto out_dir; 256 if (dir_de) 257 inode_inc_link_count(new_dir); 258 } 259 260 sysv_delete_entry(old_de, old_page); 261 mark_inode_dirty(old_inode); 262 263 if (dir_de) { 264 sysv_set_link(dir_de, dir_page, new_dir); 265 inode_dec_link_count(old_dir); 266 } 267 return 0; 268 269 out_dir: 270 if (dir_de) { 271 kunmap(dir_page); 272 put_page(dir_page); 273 } 274 out_old: 275 kunmap(old_page); 276 put_page(old_page); 277 out: 278 return err; 279 } 280 281 /* 282 * directories can handle most operations... 283 */ 284 const struct inode_operations sysv_dir_inode_operations = { 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 }; 296