1 /* $OpenBSD: rm.c,v 1.30 2015/01/16 06:39:32 deraadt 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 (argc < 1 && fflag == 0) 106 usage(); 107 108 checkdot(argv); 109 110 if (*argv) { 111 stdin_ok = isatty(STDIN_FILENO); 112 113 if (rflag) 114 rm_tree(argv); 115 else 116 rm_file(argv); 117 } 118 119 exit (eval); 120 } 121 122 void 123 rm_tree(char **argv) 124 { 125 FTS *fts; 126 FTSENT *p; 127 int needstat; 128 int flags; 129 130 /* 131 * Remove a file hierarchy. If forcing removal (-f), or interactive 132 * (-i) or can't ask anyway (stdin_ok), don't stat the file. 133 */ 134 needstat = !fflag && !iflag && stdin_ok; 135 136 /* 137 * If the -i option is specified, the user can skip on the pre-order 138 * visit. The fts_number field flags skipped directories. 139 */ 140 #define SKIPPED 1 141 142 flags = FTS_PHYSICAL; 143 if (!needstat) 144 flags |= FTS_NOSTAT; 145 if (!(fts = fts_open(argv, flags, NULL))) 146 err(1, NULL); 147 while ((p = fts_read(fts)) != NULL) { 148 switch (p->fts_info) { 149 case FTS_DNR: 150 if (!fflag || p->fts_errno != ENOENT) { 151 warnx("%s: %s", 152 p->fts_path, strerror(p->fts_errno)); 153 eval = 1; 154 } 155 continue; 156 case FTS_ERR: 157 errc(1, p->fts_errno, "%s", p->fts_path); 158 case FTS_NS: 159 /* 160 * FTS_NS: assume that if can't stat the file, it 161 * can't be unlinked. 162 */ 163 if (!needstat) 164 break; 165 if (!fflag || p->fts_errno != ENOENT) { 166 warnx("%s: %s", 167 p->fts_path, strerror(p->fts_errno)); 168 eval = 1; 169 } 170 continue; 171 case FTS_D: 172 /* Pre-order: give user chance to skip. */ 173 if (!fflag && !check(p->fts_path, p->fts_accpath, 174 p->fts_statp)) { 175 (void)fts_set(fts, p, FTS_SKIP); 176 p->fts_number = SKIPPED; 177 } 178 continue; 179 case FTS_DP: 180 /* Post-order: see if user skipped. */ 181 if (p->fts_number == SKIPPED) 182 continue; 183 break; 184 default: 185 if (!fflag && 186 !check(p->fts_path, p->fts_accpath, p->fts_statp)) 187 continue; 188 } 189 190 /* 191 * If we can't read or search the directory, may still be 192 * able to remove it. Don't print out the un{read,search}able 193 * message unless the remove fails. 194 */ 195 switch (p->fts_info) { 196 case FTS_DP: 197 case FTS_DNR: 198 if (!rmdir(p->fts_accpath) || 199 (fflag && errno == ENOENT)) 200 continue; 201 break; 202 203 case FTS_F: 204 case FTS_NSOK: 205 if (Pflag) 206 rm_overwrite(p->fts_accpath, p->fts_info == 207 FTS_NSOK ? NULL : p->fts_statp); 208 /* FALLTHROUGH */ 209 default: 210 if (!unlink(p->fts_accpath) || 211 (fflag && errno == ENOENT)) 212 continue; 213 } 214 warn("%s", p->fts_path); 215 eval = 1; 216 } 217 if (errno) 218 err(1, "fts_read"); 219 fts_close(fts); 220 } 221 222 void 223 rm_file(char **argv) 224 { 225 struct stat sb; 226 int rval; 227 char *f; 228 229 /* 230 * Remove a file. POSIX 1003.2 states that, by default, attempting 231 * to remove a directory is an error, so must always stat the file. 232 */ 233 while ((f = *argv++) != NULL) { 234 /* Assume if can't stat the file, can't unlink it. */ 235 if (lstat(f, &sb)) { 236 if (!fflag || errno != ENOENT) { 237 warn("%s", f); 238 eval = 1; 239 } 240 continue; 241 } 242 243 if (S_ISDIR(sb.st_mode) && !dflag) { 244 warnx("%s: is a directory", f); 245 eval = 1; 246 continue; 247 } 248 if (!fflag && !check(f, f, &sb)) 249 continue; 250 else if (S_ISDIR(sb.st_mode)) 251 rval = rmdir(f); 252 else { 253 if (Pflag) 254 rm_overwrite(f, &sb); 255 rval = unlink(f); 256 } 257 if (rval && (!fflag || errno != ENOENT)) { 258 warn("%s", f); 259 eval = 1; 260 } 261 } 262 } 263 264 /* 265 * rm_overwrite -- 266 * Overwrite the file with varying bit patterns. 267 * 268 * XXX 269 * This is a cheap way to *really* delete files. Note that only regular 270 * files are deleted, directories (and therefore names) will remain. 271 * Also, this assumes a fixed-block file system (like FFS, or a V7 or a 272 * System V file system). In a logging file system, you'll have to have 273 * kernel support. 274 * Returns 1 for success. 275 */ 276 int 277 rm_overwrite(char *file, struct stat *sbp) 278 { 279 struct stat sb, sb2; 280 struct statfs fsb; 281 size_t bsize; 282 int fd; 283 char *buf = NULL; 284 285 fd = -1; 286 if (sbp == NULL) { 287 if (lstat(file, &sb)) 288 goto err; 289 sbp = &sb; 290 } 291 if (!S_ISREG(sbp->st_mode)) 292 return (1); 293 if (sbp->st_nlink > 1) { 294 warnx("%s (inode %llu): not overwritten due to multiple links", 295 file, (unsigned long long)sbp->st_ino); 296 return (0); 297 } 298 if ((fd = open(file, O_WRONLY|O_NONBLOCK|O_NOFOLLOW, 0)) == -1) 299 goto err; 300 if (fstat(fd, &sb2)) 301 goto err; 302 if (sb2.st_dev != sbp->st_dev || sb2.st_ino != sbp->st_ino || 303 !S_ISREG(sb2.st_mode)) { 304 errno = EPERM; 305 goto err; 306 } 307 if (fstatfs(fd, &fsb) == -1) 308 goto err; 309 bsize = MAXIMUM(fsb.f_iosize, 1024U); 310 if ((buf = malloc(bsize)) == NULL) 311 err(1, "%s: malloc", file); 312 313 if (!pass(fd, sbp->st_size, buf, bsize)) 314 goto err; 315 if (fsync(fd)) 316 goto err; 317 close(fd); 318 free(buf); 319 return (1); 320 321 err: 322 warn("%s", file); 323 close(fd); 324 eval = 1; 325 free(buf); 326 return (0); 327 } 328 329 int 330 pass(int fd, off_t len, char *buf, size_t bsize) 331 { 332 size_t wlen; 333 334 for (; len > 0; len -= wlen) { 335 wlen = len < bsize ? len : bsize; 336 arc4random_buf(buf, wlen); 337 if (write(fd, buf, wlen) != wlen) 338 return (0); 339 } 340 return (1); 341 } 342 343 int 344 check(char *path, char *name, struct stat *sp) 345 { 346 int ch, first; 347 char modep[15]; 348 349 /* Check -i first. */ 350 if (iflag) 351 (void)fprintf(stderr, "remove %s? ", path); 352 else { 353 /* 354 * If it's not a symbolic link and it's unwritable and we're 355 * talking to a terminal, ask. Symbolic links are excluded 356 * because their permissions are meaningless. Check stdin_ok 357 * first because we may not have stat'ed the file. 358 */ 359 if (!stdin_ok || S_ISLNK(sp->st_mode) || !access(name, W_OK) || 360 errno != EACCES) 361 return (1); 362 strmode(sp->st_mode, modep); 363 (void)fprintf(stderr, "override %s%s%s/%s for %s? ", 364 modep + 1, modep[9] == ' ' ? "" : " ", 365 user_from_uid(sp->st_uid, 0), 366 group_from_gid(sp->st_gid, 0), path); 367 } 368 (void)fflush(stderr); 369 370 first = ch = getchar(); 371 while (ch != '\n' && ch != EOF) 372 ch = getchar(); 373 return (first == 'y' || first == 'Y'); 374 } 375 376 /* 377 * POSIX.2 requires that if "." or ".." are specified as the basename 378 * portion of an operand, a diagnostic message be written to standard 379 * error and nothing more be done with such operands. 380 * 381 * Since POSIX.2 defines basename as the final portion of a path after 382 * trailing slashes have been removed, we'll remove them here. 383 */ 384 #define ISDOT(a) ((a)[0] == '.' && (!(a)[1] || ((a)[1] == '.' && !(a)[2]))) 385 void 386 checkdot(char **argv) 387 { 388 char *p, **save, **t; 389 int complained; 390 391 complained = 0; 392 for (t = argv; *t;) { 393 /* strip trailing slashes */ 394 p = strrchr (*t, '\0'); 395 while (--p > *t && *p == '/') 396 *p = '\0'; 397 398 /* extract basename */ 399 if ((p = strrchr(*t, '/')) != NULL) 400 ++p; 401 else 402 p = *t; 403 404 if (ISDOT(p)) { 405 if (!complained++) 406 warnx("\".\" and \"..\" may not be removed"); 407 eval = 1; 408 for (save = t; (t[0] = t[1]) != NULL; ++t) 409 continue; 410 t = save; 411 } else 412 ++t; 413 } 414 } 415 416 void 417 usage(void) 418 { 419 (void)fprintf(stderr, "usage: %s [-dfiPRr] file ...\n", __progname); 420 exit(1); 421 } 422