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 if (ino) 55 inode = sysv_iget(dir->i_sb, ino); 56 return d_splice_alias(inode, dentry); 57 } 58 59 static int sysv_mknod(struct inode * dir, struct dentry * dentry, umode_t mode, dev_t rdev) 60 { 61 struct inode * inode; 62 int err; 63 64 if (!old_valid_dev(rdev)) 65 return -EINVAL; 66 67 inode = sysv_new_inode(dir, mode); 68 err = PTR_ERR(inode); 69 70 if (!IS_ERR(inode)) { 71 sysv_set_inode(inode, rdev); 72 mark_inode_dirty(inode); 73 err = add_nondir(dentry, inode); 74 } 75 return err; 76 } 77 78 static int sysv_create(struct inode * dir, struct dentry * dentry, umode_t mode, bool excl) 79 { 80 return sysv_mknod(dir, dentry, mode, 0); 81 } 82 83 static int sysv_symlink(struct inode * dir, struct dentry * dentry, 84 const char * symname) 85 { 86 int err = -ENAMETOOLONG; 87 int l = strlen(symname)+1; 88 struct inode * inode; 89 90 if (l > dir->i_sb->s_blocksize) 91 goto out; 92 93 inode = sysv_new_inode(dir, S_IFLNK|0777); 94 err = PTR_ERR(inode); 95 if (IS_ERR(inode)) 96 goto out; 97 98 sysv_set_inode(inode, 0); 99 err = page_symlink(inode, symname, l); 100 if (err) 101 goto out_fail; 102 103 mark_inode_dirty(inode); 104 err = add_nondir(dentry, inode); 105 out: 106 return err; 107 108 out_fail: 109 inode_dec_link_count(inode); 110 iput(inode); 111 goto out; 112 } 113 114 static int sysv_link(struct dentry * old_dentry, struct inode * dir, 115 struct dentry * dentry) 116 { 117 struct inode *inode = d_inode(old_dentry); 118 119 inode->i_ctime = current_time(inode); 120 inode_inc_link_count(inode); 121 ihold(inode); 122 123 return add_nondir(dentry, inode); 124 } 125 126 static int sysv_mkdir(struct inode * dir, struct dentry *dentry, umode_t mode) 127 { 128 struct inode * inode; 129 int err; 130 131 inode_inc_link_count(dir); 132 133 inode = sysv_new_inode(dir, S_IFDIR|mode); 134 err = PTR_ERR(inode); 135 if (IS_ERR(inode)) 136 goto out_dir; 137 138 sysv_set_inode(inode, 0); 139 140 inode_inc_link_count(inode); 141 142 err = sysv_make_empty(inode, dir); 143 if (err) 144 goto out_fail; 145 146 err = sysv_add_link(dentry, inode); 147 if (err) 148 goto out_fail; 149 150 d_instantiate(dentry, inode); 151 out: 152 return err; 153 154 out_fail: 155 inode_dec_link_count(inode); 156 inode_dec_link_count(inode); 157 iput(inode); 158 out_dir: 159 inode_dec_link_count(dir); 160 goto out; 161 } 162 163 static int sysv_unlink(struct inode * dir, struct dentry * dentry) 164 { 165 struct inode * inode = d_inode(dentry); 166 struct page * page; 167 struct sysv_dir_entry * de; 168 int err = -ENOENT; 169 170 de = sysv_find_entry(dentry, &page); 171 if (!de) 172 goto out; 173 174 err = sysv_delete_entry (de, page); 175 if (err) 176 goto out; 177 178 inode->i_ctime = dir->i_ctime; 179 inode_dec_link_count(inode); 180 out: 181 return err; 182 } 183 184 static int sysv_rmdir(struct inode * dir, struct dentry * dentry) 185 { 186 struct inode *inode = d_inode(dentry); 187 int err = -ENOTEMPTY; 188 189 if (sysv_empty_dir(inode)) { 190 err = sysv_unlink(dir, dentry); 191 if (!err) { 192 inode->i_size = 0; 193 inode_dec_link_count(inode); 194 inode_dec_link_count(dir); 195 } 196 } 197 return err; 198 } 199 200 /* 201 * Anybody can rename anything with this: the permission checks are left to the 202 * higher-level routines. 203 */ 204 static int sysv_rename(struct inode * old_dir, struct dentry * old_dentry, 205 struct inode * new_dir, struct dentry * new_dentry, 206 unsigned int flags) 207 { 208 struct inode * old_inode = d_inode(old_dentry); 209 struct inode * new_inode = d_inode(new_dentry); 210 struct page * dir_page = NULL; 211 struct sysv_dir_entry * dir_de = NULL; 212 struct page * old_page; 213 struct sysv_dir_entry * old_de; 214 int err = -ENOENT; 215 216 if (flags & ~RENAME_NOREPLACE) 217 return -EINVAL; 218 219 old_de = sysv_find_entry(old_dentry, &old_page); 220 if (!old_de) 221 goto out; 222 223 if (S_ISDIR(old_inode->i_mode)) { 224 err = -EIO; 225 dir_de = sysv_dotdot(old_inode, &dir_page); 226 if (!dir_de) 227 goto out_old; 228 } 229 230 if (new_inode) { 231 struct page * new_page; 232 struct sysv_dir_entry * new_de; 233 234 err = -ENOTEMPTY; 235 if (dir_de && !sysv_empty_dir(new_inode)) 236 goto out_dir; 237 238 err = -ENOENT; 239 new_de = sysv_find_entry(new_dentry, &new_page); 240 if (!new_de) 241 goto out_dir; 242 sysv_set_link(new_de, new_page, old_inode); 243 new_inode->i_ctime = current_time(new_inode); 244 if (dir_de) 245 drop_nlink(new_inode); 246 inode_dec_link_count(new_inode); 247 } else { 248 err = sysv_add_link(new_dentry, old_inode); 249 if (err) 250 goto out_dir; 251 if (dir_de) 252 inode_inc_link_count(new_dir); 253 } 254 255 sysv_delete_entry(old_de, old_page); 256 mark_inode_dirty(old_inode); 257 258 if (dir_de) { 259 sysv_set_link(dir_de, dir_page, new_dir); 260 inode_dec_link_count(old_dir); 261 } 262 return 0; 263 264 out_dir: 265 if (dir_de) { 266 kunmap(dir_page); 267 put_page(dir_page); 268 } 269 out_old: 270 kunmap(old_page); 271 put_page(old_page); 272 out: 273 return err; 274 } 275 276 /* 277 * directories can handle most operations... 278 */ 279 const struct inode_operations sysv_dir_inode_operations = { 280 .create = sysv_create, 281 .lookup = sysv_lookup, 282 .link = sysv_link, 283 .unlink = sysv_unlink, 284 .symlink = sysv_symlink, 285 .mkdir = sysv_mkdir, 286 .rmdir = sysv_rmdir, 287 .mknod = sysv_mknod, 288 .rename = sysv_rename, 289 .getattr = sysv_getattr, 290 }; 291