1/* $OpenBSD: walk.c,v 1.12 2023/08/19 04:21:06 guenther Exp $ */ 2/* $NetBSD: walk.c,v 1.29 2015/11/25 00:48:49 christos Exp $ */ 3 4/* 5 * Copyright (c) 2001 Wasabi Systems, Inc. 6 * All rights reserved. 7 * 8 * Written by Luke Mewburn for Wasabi Systems, Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed for the NetBSD Project by 21 * Wasabi Systems, Inc. 22 * 4. The name of Wasabi Systems, Inc. may not be used to endorse 23 * or promote products derived from this software without specific prior 24 * written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY WASABI SYSTEMS, INC. ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL WASABI SYSTEMS, INC 30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 * POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39#include <sys/types.h> 40#include <sys/stat.h> 41 42#include <assert.h> 43#include <stdio.h> 44#include <dirent.h> 45#include <stdlib.h> 46#include <limits.h> 47#include <string.h> 48#include <unistd.h> 49 50#include "makefs.h" 51 52static fsnode *create_fsnode(const char *, const char *, const char *, 53 struct stat *); 54static fsinode *link_check(fsinode *); 55 56 57/* 58 * walk_dir -- 59 * build a tree of fsnodes from `root' and `dir', with a parent 60 * fsnode of `parent' (which may be NULL for the root of the tree). 61 * append the tree to a fsnode of `join' if it is not NULL. 62 * each "level" is a directory, with the "." entry guaranteed to be 63 * at the start of the list, and without ".." entries. 64 */ 65fsnode * 66walk_dir(const char *root, const char *dir, fsnode *parent, fsnode *join) 67{ 68 fsnode *first, *cur, *prev, *last; 69 DIR *dirp; 70 struct dirent *dent; 71 char path[PATH_MAX+1]; 72 struct stat stbuf; 73 char *name, *rp; 74 int dot, len; 75 76 assert(root != NULL); 77 assert(dir != NULL); 78 79 len = snprintf(path, sizeof(path), "%s/%s", root, dir); 80 if (len >= (int)sizeof(path)) 81 errx(1, "Pathname too long."); 82 if ((dirp = opendir(path)) == NULL) 83 err(1, "Can't opendir `%s'", path); 84 rp = path + strlen(root) + 1; 85 if (join != NULL) { 86 first = cur = join; 87 while (cur->next != NULL) 88 cur = cur->next; 89 prev = last = cur; 90 } else 91 last = first = prev = NULL; 92 while ((dent = readdir(dirp)) != NULL) { 93 name = dent->d_name; 94 dot = 0; 95 if (name[0] == '.') 96 switch (name[1]) { 97 case '\0': /* "." */ 98 if (join != NULL) 99 continue; 100 dot = 1; 101 break; 102 case '.': /* ".." */ 103 if (name[2] == '\0') 104 continue; 105 /* FALLTHROUGH */ 106 default: 107 dot = 0; 108 } 109 if (snprintf(path + len, sizeof(path) - len, "/%s", name) >= 110 (int)sizeof(path) - len) 111 errx(1, "Pathname too long."); 112 if (lstat(path, &stbuf) == -1) 113 err(1, "Can't lstat `%s'", path); 114 if (S_ISSOCK(stbuf.st_mode & S_IFMT)) 115 continue; 116 117 if (join != NULL) { 118 cur = join->next; 119 for (;;) { 120 if (cur == NULL || strcmp(cur->name, name) == 0) 121 break; 122 if (cur == last) { 123 cur = NULL; 124 break; 125 } 126 cur = cur->next; 127 } 128 if (cur != NULL) { 129 if (S_ISDIR(cur->type) && 130 S_ISDIR(stbuf.st_mode)) { 131 cur->child = walk_dir(root, rp, cur, 132 cur->child); 133 continue; 134 } 135 errx(1, "Can't merge %s `%s' with " 136 "existing %s", 137 inode_type(stbuf.st_mode), path, 138 inode_type(cur->type)); 139 } 140 } 141 142 cur = create_fsnode(root, dir, name, &stbuf); 143 cur->parent = parent; 144 if (dot) { 145 /* ensure "." is at the start of the list */ 146 cur->next = first; 147 first = cur; 148 if (! prev) 149 prev = cur; 150 cur->first = first; 151 } else { /* not "." */ 152 if (prev) 153 prev->next = cur; 154 prev = cur; 155 if (!first) 156 first = cur; 157 cur->first = first; 158 if (S_ISDIR(cur->type)) { 159 cur->child = walk_dir(root, rp, cur, NULL); 160 continue; 161 } 162 } 163 if (stbuf.st_nlink > 1) { 164 fsinode *curino; 165 166 curino = link_check(cur->inode); 167 if (curino != NULL) { 168 free(cur->inode); 169 cur->inode = curino; 170 cur->inode->nlink++; 171 } 172 } 173 if (S_ISLNK(cur->type)) { 174 char slink[PATH_MAX+1]; 175 int llen; 176 177 llen = readlink(path, slink, sizeof(slink) - 1); 178 if (llen == -1) 179 err(1, "Readlink `%s'", path); 180 slink[llen] = '\0'; 181 cur->symlink = estrdup(slink); 182 } 183 } 184 assert(first != NULL); 185 if (join == NULL) 186 for (cur = first->next; cur != NULL; cur = cur->next) 187 cur->first = first; 188 if (closedir(dirp) == -1) 189 err(1, "Can't closedir `%s/%s'", root, dir); 190 return (first); 191} 192 193static fsnode * 194create_fsnode(const char *root, const char *path, const char *name, 195 struct stat *stbuf) 196{ 197 fsnode *cur; 198 199 cur = ecalloc(1, sizeof(*cur)); 200 cur->path = estrdup(path); 201 cur->name = estrdup(name); 202 cur->inode = ecalloc(1, sizeof(*cur->inode)); 203 cur->root = root; 204 cur->type = stbuf->st_mode & S_IFMT; 205 cur->inode->nlink = 1; 206 cur->inode->st = *stbuf; 207 if (Tflag) { 208 cur->inode->st.st_atim.tv_sec = stampts; 209 cur->inode->st.st_atim.tv_nsec = 0; 210 cur->inode->st.st_mtim = cur->inode->st.st_ctim = 211 cur->inode->st.st_atim; 212 } 213 return (cur); 214} 215 216/* 217 * free_fsnodes -- 218 * Removes node from tree and frees it and all of 219 * its descendants. 220 */ 221void 222free_fsnodes(fsnode *node) 223{ 224 fsnode *cur, *next; 225 226 assert(node != NULL); 227 228 /* for ".", start with actual parent node */ 229 if (node->first == node) { 230 assert(node->name[0] == '.' && node->name[1] == '\0'); 231 if (node->parent) { 232 assert(node->parent->child == node); 233 node = node->parent; 234 } 235 } 236 237 /* Find ourselves in our sibling list and unlink */ 238 if (node->first != node) { 239 for (cur = node->first; cur->next; cur = cur->next) { 240 if (cur->next == node) { 241 cur->next = node->next; 242 node->next = NULL; 243 break; 244 } 245 } 246 } 247 248 for (cur = node; cur != NULL; cur = next) { 249 next = cur->next; 250 if (cur->child) { 251 cur->child->parent = NULL; 252 free_fsnodes(cur->child); 253 } 254 if (cur->inode->nlink-- == 1) 255 free(cur->inode); 256 if (cur->symlink) 257 free(cur->symlink); 258 free(cur->path); 259 free(cur->name); 260 free(cur); 261 } 262} 263 264 265/* 266 * inode_type -- 267 * for a given inode type `mode', return a descriptive string. 268 * for most cases, uses inotype() from mtree/misc.c 269 */ 270const char * 271inode_type(mode_t mode) 272{ 273 switch (mode & S_IFMT) { 274 case S_IFBLK: 275 return ("block"); 276 case S_IFCHR: 277 return ("char"); 278 case S_IFDIR: 279 return ("dir"); 280 case S_IFIFO: 281 return ("fifo"); 282 case S_IFREG: 283 return ("file"); 284 case S_IFLNK: 285 return ("symlink"); 286 case S_IFSOCK: 287 return ("socket"); 288 default: 289 return ("unknown"); 290 } 291} 292 293 294/* 295 * link_check -- 296 * return pointer to fsinode matching `entry's st_ino & st_dev if it exists, 297 * otherwise add `entry' to table and return NULL 298 */ 299/* This was borrowed from du.c and tweaked to keep an fsnode 300 * pointer instead. -- dbj@netbsd.org 301 */ 302static fsinode * 303link_check(fsinode *entry) 304{ 305 static struct entry { 306 fsinode *data; 307 } *htable; 308 static int htshift; /* log(allocated size) */ 309 static int htmask; /* allocated size - 1 */ 310 static int htused; /* 2*number of insertions */ 311 int h, h2; 312 uint64_t tmp; 313 /* this constant is (1<<64)/((1+sqrt(5))/2) 314 * aka (word size)/(golden ratio) 315 */ 316 const uint64_t HTCONST = 11400714819323198485ULL; 317 const int HTBITS = 64; 318 319 /* Never store zero in hashtable */ 320 assert(entry); 321 322 /* Extend hash table if necessary, keep load under 0.5 */ 323 if (htused<<1 >= htmask) { 324 struct entry *ohtable; 325 326 if (!htable) 327 htshift = 10; /* starting hashtable size */ 328 else 329 htshift++; /* exponential hashtable growth */ 330 331 htmask = (1 << htshift) - 1; 332 htused = 0; 333 334 ohtable = htable; 335 htable = ecalloc(htmask+1, sizeof(*htable)); 336 /* populate newly allocated hashtable */ 337 if (ohtable) { 338 int i; 339 for (i = 0; i <= htmask>>1; i++) 340 if (ohtable[i].data) 341 link_check(ohtable[i].data); 342 free(ohtable); 343 } 344 } 345 346 /* multiplicative hashing */ 347 tmp = entry->st.st_dev; 348 tmp <<= HTBITS>>1; 349 tmp |= entry->st.st_ino; 350 tmp *= HTCONST; 351 h = tmp >> (HTBITS - htshift); 352 h2 = 1 | ( tmp >> (HTBITS - (htshift<<1) - 1)); /* must be odd */ 353 354 /* open address hashtable search with double hash probing */ 355 while (htable[h].data) { 356 if ((htable[h].data->st.st_ino == entry->st.st_ino) && 357 (htable[h].data->st.st_dev == entry->st.st_dev)) { 358 return htable[h].data; 359 } 360 h = (h + h2) & htmask; 361 } 362 363 /* Insert the current entry into hashtable */ 364 htable[h].data = entry; 365 htused++; 366 return NULL; 367} 368