1 /*- 2 * SPDX-License-Identifier: BSD-3-Clause 3 * 4 * Copyright (c) 1987, 1993, 1994 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of the University nor the names of its contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 #if 0 33 #ifndef lint 34 static char const copyright[] = 35 "@(#) Copyright (c) 1987, 1993, 1994\n\ 36 The Regents of the University of California. All rights reserved.\n"; 37 #endif /* not lint */ 38 39 #endif 40 #include <sys/cdefs.h> 41 #include <sys/param.h> 42 #include <sys/stat.h> 43 44 #include <err.h> 45 #include <errno.h> 46 #include <fcntl.h> 47 #include <libgen.h> 48 #include <limits.h> 49 #include <stdio.h> 50 #include <stdlib.h> 51 #include <string.h> 52 #include <unistd.h> 53 54 static int fflag; /* Unlink existing files. */ 55 static int Fflag; /* Remove empty directories also. */ 56 static int hflag; /* Check new name for symlink first. */ 57 static int iflag; /* Interactive mode. */ 58 static int Pflag; /* Create hard links to symlinks. */ 59 static int sflag; /* Symbolic, not hard, link. */ 60 static int vflag; /* Verbose output. */ 61 static int wflag; /* Warn if symlink target does not 62 * exist, and -f is not enabled. */ 63 static char linkch; 64 65 static int linkit(const char *, const char *, int); 66 static void usage(void); 67 68 int 69 main(int argc, char *argv[]) 70 { 71 struct stat sb; 72 char *p, *targetdir; 73 int ch, exitval; 74 75 /* 76 * Test for the special case where the utility is called as 77 * "link", for which the functionality provided is greatly 78 * simplified. 79 */ 80 if ((p = strrchr(argv[0], '/')) == NULL) 81 p = argv[0]; 82 else 83 ++p; 84 if (strcmp(p, "link") == 0) { 85 while (getopt(argc, argv, "") != -1) 86 usage(); 87 argc -= optind; 88 argv += optind; 89 if (argc != 2) 90 usage(); 91 exit(linkit(argv[0], argv[1], 0)); 92 } 93 94 while ((ch = getopt(argc, argv, "FLPfhinsvw")) != -1) 95 switch (ch) { 96 case 'F': 97 Fflag = 1; 98 break; 99 case 'L': 100 Pflag = 0; 101 break; 102 case 'P': 103 Pflag = 1; 104 break; 105 case 'f': 106 fflag = 1; 107 iflag = 0; 108 wflag = 0; 109 break; 110 case 'h': 111 case 'n': 112 hflag = 1; 113 break; 114 case 'i': 115 iflag = 1; 116 fflag = 0; 117 break; 118 case 's': 119 sflag = 1; 120 break; 121 case 'v': 122 vflag = 1; 123 break; 124 case 'w': 125 wflag = 1; 126 break; 127 case '?': 128 default: 129 usage(); 130 } 131 132 argv += optind; 133 argc -= optind; 134 135 linkch = sflag ? '-' : '='; 136 if (sflag == 0) 137 Fflag = 0; 138 if (Fflag == 1 && iflag == 0) { 139 fflag = 1; 140 wflag = 0; /* Implied when fflag != 0 */ 141 } 142 143 switch(argc) { 144 case 0: 145 usage(); 146 /* NOTREACHED */ 147 case 1: /* ln source */ 148 exit(linkit(argv[0], ".", 1)); 149 case 2: /* ln source target */ 150 exit(linkit(argv[0], argv[1], 0)); 151 default: 152 ; 153 } 154 /* ln source1 source2 directory */ 155 targetdir = argv[argc - 1]; 156 if (hflag && lstat(targetdir, &sb) == 0 && S_ISLNK(sb.st_mode)) { 157 /* 158 * We were asked not to follow symlinks, but found one at 159 * the target--simulate "not a directory" error 160 */ 161 errno = ENOTDIR; 162 err(1, "%s", targetdir); 163 } 164 if (stat(targetdir, &sb)) 165 err(1, "%s", targetdir); 166 if (!S_ISDIR(sb.st_mode)) 167 usage(); 168 for (exitval = 0; *argv != targetdir; ++argv) 169 exitval |= linkit(*argv, targetdir, 1); 170 exit(exitval); 171 } 172 173 /* 174 * Two pathnames refer to the same directory entry if the directories match 175 * and the final components' names match. 176 */ 177 static int 178 samedirent(const char *path1, const char *path2) 179 { 180 const char *file1, *file2; 181 char pathbuf[PATH_MAX]; 182 struct stat sb1, sb2; 183 184 if (strcmp(path1, path2) == 0) 185 return 1; 186 file1 = strrchr(path1, '/'); 187 if (file1 != NULL) 188 file1++; 189 else 190 file1 = path1; 191 file2 = strrchr(path2, '/'); 192 if (file2 != NULL) 193 file2++; 194 else 195 file2 = path2; 196 if (strcmp(file1, file2) != 0) 197 return 0; 198 if (file1 - path1 >= PATH_MAX || file2 - path2 >= PATH_MAX) 199 return 0; 200 if (file1 == path1) 201 memcpy(pathbuf, ".", 2); 202 else { 203 memcpy(pathbuf, path1, file1 - path1); 204 pathbuf[file1 - path1] = '\0'; 205 } 206 if (stat(pathbuf, &sb1) != 0) 207 return 0; 208 if (file2 == path2) 209 memcpy(pathbuf, ".", 2); 210 else { 211 memcpy(pathbuf, path2, file2 - path2); 212 pathbuf[file2 - path2] = '\0'; 213 } 214 if (stat(pathbuf, &sb2) != 0) 215 return 0; 216 return sb1.st_dev == sb2.st_dev && sb1.st_ino == sb2.st_ino; 217 } 218 219 static int 220 linkit(const char *source, const char *target, int isdir) 221 { 222 struct stat sb; 223 const char *p; 224 int ch, exists, first; 225 char path[PATH_MAX]; 226 char wbuf[PATH_MAX]; 227 char bbuf[PATH_MAX]; 228 229 if (!sflag) { 230 /* If source doesn't exist, quit now. */ 231 if ((Pflag ? lstat : stat)(source, &sb)) { 232 warn("%s", source); 233 return (1); 234 } 235 /* Only symbolic links to directories. */ 236 if (S_ISDIR(sb.st_mode)) { 237 errno = EISDIR; 238 warn("%s", source); 239 return (1); 240 } 241 } 242 243 /* 244 * If the target is a directory (and not a symlink if hflag), 245 * append the source's name, unless Fflag is set. 246 */ 247 if (!Fflag && (isdir || 248 (lstat(target, &sb) == 0 && S_ISDIR(sb.st_mode)) || 249 (!hflag && stat(target, &sb) == 0 && S_ISDIR(sb.st_mode)))) { 250 if (strlcpy(bbuf, source, sizeof(bbuf)) >= sizeof(bbuf) || 251 (p = basename(bbuf)) == NULL || 252 snprintf(path, sizeof(path), "%s/%s", target, p) >= 253 (ssize_t)sizeof(path)) { 254 errno = ENAMETOOLONG; 255 warn("%s", source); 256 return (1); 257 } 258 target = path; 259 } 260 261 /* 262 * If the link source doesn't exist, and a symbolic link was 263 * requested, and -w was specified, give a warning. 264 */ 265 if (sflag && wflag) { 266 if (*source == '/') { 267 /* Absolute link source. */ 268 if (stat(source, &sb) != 0) 269 warn("warning: %s inaccessible", source); 270 } else { 271 /* 272 * Relative symlink source. Try to construct the 273 * absolute path of the source, by appending `source' 274 * to the parent directory of the target. 275 */ 276 strlcpy(bbuf, target, sizeof(bbuf)); 277 p = dirname(bbuf); 278 if (p != NULL) { 279 (void)snprintf(wbuf, sizeof(wbuf), "%s/%s", 280 p, source); 281 if (stat(wbuf, &sb) != 0) 282 warn("warning: %s", source); 283 } 284 } 285 } 286 287 /* 288 * If the file exists, first check it is not the same directory entry. 289 */ 290 exists = !lstat(target, &sb); 291 if (exists) { 292 if (!sflag && samedirent(source, target)) { 293 warnx("%s and %s are the same directory entry", 294 source, target); 295 return (1); 296 } 297 } 298 /* 299 * Then unlink it forcibly if -f was specified 300 * and interactively if -i was specified. 301 */ 302 if (fflag && exists) { 303 if (Fflag && S_ISDIR(sb.st_mode)) { 304 if (rmdir(target)) { 305 warn("%s", target); 306 return (1); 307 } 308 } else if (unlink(target)) { 309 warn("%s", target); 310 return (1); 311 } 312 } else if (iflag && exists) { 313 fflush(stdout); 314 fprintf(stderr, "replace %s? ", target); 315 316 first = ch = getchar(); 317 while(ch != '\n' && ch != EOF) 318 ch = getchar(); 319 if (first != 'y' && first != 'Y') { 320 fprintf(stderr, "not replaced\n"); 321 return (1); 322 } 323 324 if (Fflag && S_ISDIR(sb.st_mode)) { 325 if (rmdir(target)) { 326 warn("%s", target); 327 return (1); 328 } 329 } else if (unlink(target)) { 330 warn("%s", target); 331 return (1); 332 } 333 } 334 335 /* Attempt the link. */ 336 if (sflag ? symlink(source, target) : 337 linkat(AT_FDCWD, source, AT_FDCWD, target, 338 Pflag ? 0 : AT_SYMLINK_FOLLOW)) { 339 warn("%s", target); 340 return (1); 341 } 342 if (vflag) 343 (void)printf("%s %c> %s\n", target, linkch, source); 344 return (0); 345 } 346 347 static void 348 usage(void) 349 { 350 (void)fprintf(stderr, "%s\n%s\n%s\n", 351 "usage: ln [-s [-F] | -L | -P] [-f | -i] [-hnv] source_file [target_file]", 352 " ln [-s [-F] | -L | -P] [-f | -i] [-hnv] source_file ... target_dir", 353 " link source_file target_file"); 354 exit(1); 355 } 356