1 /* $OpenBSD: rm.c,v 1.39 2016/06/28 18:00:59 tedu Exp $ */ 2 /* $NetBSD: rm.c,v 1.19 1995/09/07 06:48:50 jtc Exp $ */ 3 4 /*- 5 * Copyright (c) 1990, 1993, 1994 6 * The Regents of the University of California. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of the University nor the names of its contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 */ 32 33 #include <sys/types.h> 34 #include <sys/stat.h> 35 #include <sys/mount.h> 36 37 #include <locale.h> 38 #include <err.h> 39 #include <errno.h> 40 #include <fcntl.h> 41 #include <fts.h> 42 #include <stdio.h> 43 #include <stdlib.h> 44 #include <string.h> 45 #include <unistd.h> 46 #include <limits.h> 47 #include <pwd.h> 48 #include <grp.h> 49 50 #define MAXIMUM(a, b) (((a) > (b)) ? (a) : (b)) 51 52 extern char *__progname; 53 54 int dflag, eval, fflag, iflag, Pflag, stdin_ok; 55 56 int check(char *, char *, struct stat *); 57 void checkdot(char **); 58 void rm_file(char **); 59 int rm_overwrite(char *, struct stat *); 60 int pass(int, off_t, char *, size_t); 61 void rm_tree(char **); 62 void usage(void); 63 64 /* 65 * rm -- 66 * This rm is different from historic rm's, but is expected to match 67 * POSIX 1003.2 behavior. The most visible difference is that -f 68 * has two specific effects now, ignore non-existent files and force 69 * file removal. 70 */ 71 int 72 main(int argc, char *argv[]) 73 { 74 int ch, rflag; 75 76 setlocale(LC_ALL, ""); 77 78 Pflag = rflag = 0; 79 while ((ch = getopt(argc, argv, "dfiPRr")) != -1) 80 switch(ch) { 81 case 'd': 82 dflag = 1; 83 break; 84 case 'f': 85 fflag = 1; 86 iflag = 0; 87 break; 88 case 'i': 89 fflag = 0; 90 iflag = 1; 91 break; 92 case 'P': 93 Pflag = 1; 94 break; 95 case 'R': 96 case 'r': /* Compatibility. */ 97 rflag = 1; 98 break; 99 default: 100 usage(); 101 } 102 argc -= optind; 103 argv += optind; 104 105 if (Pflag) { 106 if (pledge("stdio rpath wpath cpath getpw", NULL) == -1) 107 err(1, "pledge"); 108 } else { 109 if (pledge("stdio rpath cpath getpw", NULL) == -1) 110 err(1, "pledge"); 111 } 112 113 if (argc < 1 && fflag == 0) 114 usage(); 115 116 checkdot(argv); 117 118 if (*argv) { 119 stdin_ok = isatty(STDIN_FILENO); 120 121 if (rflag) 122 rm_tree(argv); 123 else 124 rm_file(argv); 125 } 126 127 exit(eval); 128 } 129 130 void 131 rm_tree(char **argv) 132 { 133 FTS *fts; 134 FTSENT *p; 135 int needstat; 136 int flags; 137 138 /* 139 * Remove a file hierarchy. If forcing removal (-f), or interactive 140 * (-i) or can't ask anyway (stdin_ok), don't stat the file. 141 */ 142 needstat = !fflag && !iflag && stdin_ok; 143 144 /* 145 * If the -i option is specified, the user can skip on the pre-order 146 * visit. The fts_number field flags skipped directories. 147 */ 148 #define SKIPPED 1 149 150 flags = FTS_PHYSICAL; 151 if (!needstat) 152 flags |= FTS_NOSTAT; 153 if (!(fts = fts_open(argv, flags, NULL))) 154 err(1, NULL); 155 while ((p = fts_read(fts)) != NULL) { 156 switch (p->fts_info) { 157 case FTS_DNR: 158 if (!fflag || p->fts_errno != ENOENT) { 159 warnx("%s: %s", 160 p->fts_path, strerror(p->fts_errno)); 161 eval = 1; 162 } 163 continue; 164 case FTS_ERR: 165 errc(1, p->fts_errno, "%s", p->fts_path); 166 case FTS_NS: 167 /* 168 * FTS_NS: assume that if can't stat the file, it 169 * can't be unlinked. 170 */ 171 if (!needstat) 172 break; 173 if (!fflag || p->fts_errno != ENOENT) { 174 warnx("%s: %s", 175 p->fts_path, strerror(p->fts_errno)); 176 eval = 1; 177 } 178 continue; 179 case FTS_D: 180 /* Pre-order: give user chance to skip. */ 181 if (!fflag && !check(p->fts_path, p->fts_accpath, 182 p->fts_statp)) { 183 (void)fts_set(fts, p, FTS_SKIP); 184 p->fts_number = SKIPPED; 185 } 186 continue; 187 case FTS_DP: 188 /* Post-order: see if user skipped. */ 189 if (p->fts_number == SKIPPED) 190 continue; 191 break; 192 default: 193 if (!fflag && 194 !check(p->fts_path, p->fts_accpath, p->fts_statp)) 195 continue; 196 } 197 198 /* 199 * If we can't read or search the directory, may still be 200 * able to remove it. Don't print out the un{read,search}able 201 * message unless the remove fails. 202 */ 203 switch (p->fts_info) { 204 case FTS_DP: 205 case FTS_DNR: 206 if (!rmdir(p->fts_accpath) || 207 (fflag && errno == ENOENT)) 208 continue; 209 break; 210 211 case FTS_F: 212 case FTS_NSOK: 213 if (Pflag) 214 rm_overwrite(p->fts_accpath, p->fts_info == 215 FTS_NSOK ? NULL : p->fts_statp); 216 /* FALLTHROUGH */ 217 default: 218 if (!unlink(p->fts_accpath) || 219 (fflag && errno == ENOENT)) 220 continue; 221 } 222 warn("%s", p->fts_path); 223 eval = 1; 224 } 225 if (errno) 226 err(1, "fts_read"); 227 fts_close(fts); 228 } 229 230 void 231 rm_file(char **argv) 232 { 233 struct stat sb; 234 int rval; 235 char *f; 236 237 /* 238 * Remove a file. POSIX 1003.2 states that, by default, attempting 239 * to remove a directory is an error, so must always stat the file. 240 */ 241 while ((f = *argv++) != NULL) { 242 /* Assume if can't stat the file, can't unlink it. */ 243 if (lstat(f, &sb)) { 244 if (!fflag || errno != ENOENT) { 245 warn("%s", f); 246 eval = 1; 247 } 248 continue; 249 } 250 251 if (S_ISDIR(sb.st_mode) && !dflag) { 252 warnx("%s: is a directory", f); 253 eval = 1; 254 continue; 255 } 256 if (!fflag && !check(f, f, &sb)) 257 continue; 258 else if (S_ISDIR(sb.st_mode)) 259 rval = rmdir(f); 260 else { 261 if (Pflag) 262 rm_overwrite(f, &sb); 263 rval = unlink(f); 264 } 265 if (rval && (!fflag || errno != ENOENT)) { 266 warn("%s", f); 267 eval = 1; 268 } 269 } 270 } 271 272 /* 273 * rm_overwrite -- 274 * Overwrite the file with varying bit patterns. 275 * 276 * XXX 277 * This is a cheap way to *really* delete files. Note that only regular 278 * files are deleted, directories (and therefore names) will remain. 279 * Also, this assumes a fixed-block file system (like FFS, or a V7 or a 280 * System V file system). In a logging file system, you'll have to have 281 * kernel support. 282 * Returns 1 for success. 283 */ 284 int 285 rm_overwrite(char *file, struct stat *sbp) 286 { 287 struct stat sb, sb2; 288 struct statfs fsb; 289 size_t bsize; 290 int fd; 291 char *buf = NULL; 292 293 fd = -1; 294 if (sbp == NULL) { 295 if (lstat(file, &sb)) 296 goto err; 297 sbp = &sb; 298 } 299 if (!S_ISREG(sbp->st_mode)) 300 return (1); 301 if (sbp->st_nlink > 1) { 302 warnx("%s (inode %llu): not overwritten due to multiple links", 303 file, (unsigned long long)sbp->st_ino); 304 return (0); 305 } 306 if ((fd = open(file, O_WRONLY|O_NONBLOCK|O_NOFOLLOW, 0)) == -1) 307 goto err; 308 if (fstat(fd, &sb2)) 309 goto err; 310 if (sb2.st_dev != sbp->st_dev || sb2.st_ino != sbp->st_ino || 311 !S_ISREG(sb2.st_mode)) { 312 errno = EPERM; 313 goto err; 314 } 315 if (fstatfs(fd, &fsb) == -1) 316 goto err; 317 bsize = MAXIMUM(fsb.f_iosize, 1024U); 318 if ((buf = malloc(bsize)) == NULL) 319 err(1, "%s: malloc", file); 320 321 if (!pass(fd, sbp->st_size, buf, bsize)) 322 goto err; 323 if (fsync(fd)) 324 goto err; 325 close(fd); 326 free(buf); 327 return (1); 328 329 err: 330 warn("%s", file); 331 close(fd); 332 eval = 1; 333 free(buf); 334 return (0); 335 } 336 337 int 338 pass(int fd, off_t len, char *buf, size_t bsize) 339 { 340 size_t wlen; 341 342 for (; len > 0; len -= wlen) { 343 wlen = len < bsize ? len : bsize; 344 arc4random_buf(buf, wlen); 345 if (write(fd, buf, wlen) != wlen) 346 return (0); 347 } 348 return (1); 349 } 350 351 int 352 check(char *path, char *name, struct stat *sp) 353 { 354 int ch, first; 355 char modep[15]; 356 357 /* Check -i first. */ 358 if (iflag) 359 (void)fprintf(stderr, "remove %s? ", path); 360 else { 361 /* 362 * If it's not a symbolic link and it's unwritable and we're 363 * talking to a terminal, ask. Symbolic links are excluded 364 * because their permissions are meaningless. Check stdin_ok 365 * first because we may not have stat'ed the file. 366 */ 367 if (!stdin_ok || S_ISLNK(sp->st_mode) || !access(name, W_OK) || 368 errno != EACCES) 369 return (1); 370 strmode(sp->st_mode, modep); 371 (void)fprintf(stderr, "override %s%s%s/%s for %s? ", 372 modep + 1, modep[9] == ' ' ? "" : " ", 373 user_from_uid(sp->st_uid, 0), 374 group_from_gid(sp->st_gid, 0), path); 375 } 376 (void)fflush(stderr); 377 378 first = ch = getchar(); 379 while (ch != '\n' && ch != EOF) 380 ch = getchar(); 381 return (first == 'y' || first == 'Y'); 382 } 383 384 /* 385 * POSIX.2 requires that if "." or ".." are specified as the basename 386 * portion of an operand, a diagnostic message be written to standard 387 * error and nothing more be done with such operands. 388 * 389 * Since POSIX.2 defines basename as the final portion of a path after 390 * trailing slashes have been removed, we'll remove them here. 391 */ 392 #define ISDOT(a) ((a)[0] == '.' && (!(a)[1] || ((a)[1] == '.' && !(a)[2]))) 393 void 394 checkdot(char **argv) 395 { 396 char *p, **save, **t; 397 int complained; 398 struct stat sb, root; 399 400 stat("/", &root); 401 complained = 0; 402 for (t = argv; *t;) { 403 if (lstat(*t, &sb) == 0 && 404 root.st_ino == sb.st_ino && root.st_dev == sb.st_dev) { 405 if (!complained++) 406 warnx("\"/\" may not be removed"); 407 goto skip; 408 } 409 /* strip trailing slashes */ 410 p = strrchr(*t, '\0'); 411 while (--p > *t && *p == '/') 412 *p = '\0'; 413 414 /* extract basename */ 415 if ((p = strrchr(*t, '/')) != NULL) 416 ++p; 417 else 418 p = *t; 419 420 if (ISDOT(p)) { 421 if (!complained++) 422 warnx("\".\" and \"..\" may not be removed"); 423 skip: 424 eval = 1; 425 for (save = t; (t[0] = t[1]) != NULL; ++t) 426 continue; 427 t = save; 428 } else 429 ++t; 430 } 431 } 432 433 void 434 usage(void) 435 { 436 (void)fprintf(stderr, "usage: %s [-dfiPRr] file ...\n", __progname); 437 exit(1); 438 } 439