1 /*- 2 * Copyright (c) 1987, 1993, 1994 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 4. Neither the name of the University nor the names of its contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 */ 29 30 #if 0 31 #ifndef lint 32 static char const copyright[] = 33 "@(#) Copyright (c) 1987, 1993, 1994\n\ 34 The Regents of the University of California. All rights reserved.\n"; 35 #endif /* not lint */ 36 37 #ifndef lint 38 static char sccsid[] = "@(#)ln.c 8.2 (Berkeley) 3/31/94"; 39 #endif /* not lint */ 40 #endif 41 #include <sys/cdefs.h> 42 __FBSDID("$FreeBSD$"); 43 44 #include <sys/param.h> 45 #include <sys/stat.h> 46 47 #include <err.h> 48 #include <errno.h> 49 #include <fcntl.h> 50 #include <libgen.h> 51 #include <limits.h> 52 #include <stdio.h> 53 #include <stdlib.h> 54 #include <string.h> 55 #include <unistd.h> 56 57 static int fflag; /* Unlink existing files. */ 58 static int Fflag; /* Remove empty directories also. */ 59 static int hflag; /* Check new name for symlink first. */ 60 static int iflag; /* Interactive mode. */ 61 static int Pflag; /* Create hard links to symlinks. */ 62 static int sflag; /* Symbolic, not hard, link. */ 63 static int vflag; /* Verbose output. */ 64 static int wflag; /* Warn if symlink target does not 65 * exist, and -f is not enabled. */ 66 static char linkch; 67 68 static int linkit(const char *, const char *, int); 69 static void usage(void); 70 71 int 72 main(int argc, char *argv[]) 73 { 74 struct stat sb; 75 char *p, *targetdir; 76 int ch, exitval; 77 78 /* 79 * Test for the special case where the utility is called as 80 * "link", for which the functionality provided is greatly 81 * simplified. 82 */ 83 if ((p = strrchr(argv[0], '/')) == NULL) 84 p = argv[0]; 85 else 86 ++p; 87 if (strcmp(p, "link") == 0) { 88 while (getopt(argc, argv, "") != -1) 89 usage(); 90 argc -= optind; 91 argv += optind; 92 if (argc != 2) 93 usage(); 94 exit(linkit(argv[0], argv[1], 0)); 95 } 96 97 while ((ch = getopt(argc, argv, "FLPfhinsvw")) != -1) 98 switch (ch) { 99 case 'F': 100 Fflag = 1; 101 break; 102 case 'L': 103 Pflag = 0; 104 break; 105 case 'P': 106 Pflag = 1; 107 break; 108 case 'f': 109 fflag = 1; 110 iflag = 0; 111 wflag = 0; 112 break; 113 case 'h': 114 case 'n': 115 hflag = 1; 116 break; 117 case 'i': 118 iflag = 1; 119 fflag = 0; 120 break; 121 case 's': 122 sflag = 1; 123 break; 124 case 'v': 125 vflag = 1; 126 break; 127 case 'w': 128 wflag = 1; 129 break; 130 case '?': 131 default: 132 usage(); 133 } 134 135 argv += optind; 136 argc -= optind; 137 138 linkch = sflag ? '-' : '='; 139 if (sflag == 0) 140 Fflag = 0; 141 if (Fflag == 1 && iflag == 0) { 142 fflag = 1; 143 wflag = 0; /* Implied when fflag != 0 */ 144 } 145 146 switch(argc) { 147 case 0: 148 usage(); 149 /* NOTREACHED */ 150 case 1: /* ln source */ 151 exit(linkit(argv[0], ".", 1)); 152 case 2: /* ln source target */ 153 exit(linkit(argv[0], argv[1], 0)); 154 default: 155 ; 156 } 157 /* ln source1 source2 directory */ 158 targetdir = argv[argc - 1]; 159 if (hflag && lstat(targetdir, &sb) == 0 && S_ISLNK(sb.st_mode)) { 160 /* 161 * We were asked not to follow symlinks, but found one at 162 * the target--simulate "not a directory" error 163 */ 164 errno = ENOTDIR; 165 err(1, "%s", targetdir); 166 } 167 if (stat(targetdir, &sb)) 168 err(1, "%s", targetdir); 169 if (!S_ISDIR(sb.st_mode)) 170 usage(); 171 for (exitval = 0; *argv != targetdir; ++argv) 172 exitval |= linkit(*argv, targetdir, 1); 173 exit(exitval); 174 } 175 176 /* 177 * Two pathnames refer to the same directory entry if the directories match 178 * and the final components' names match. 179 */ 180 static int 181 samedirent(const char *path1, const char *path2) 182 { 183 const char *file1, *file2; 184 char pathbuf[PATH_MAX]; 185 struct stat sb1, sb2; 186 187 if (strcmp(path1, path2) == 0) 188 return 1; 189 file1 = strrchr(path1, '/'); 190 if (file1 != NULL) 191 file1++; 192 else 193 file1 = path1; 194 file2 = strrchr(path2, '/'); 195 if (file2 != NULL) 196 file2++; 197 else 198 file2 = path2; 199 if (strcmp(file1, file2) != 0) 200 return 0; 201 if (file1 - path1 >= PATH_MAX || file2 - path2 >= PATH_MAX) 202 return 0; 203 if (file1 == path1) 204 memcpy(pathbuf, ".", 2); 205 else { 206 memcpy(pathbuf, path1, file1 - path1); 207 pathbuf[file1 - path1] = '\0'; 208 } 209 if (stat(pathbuf, &sb1) != 0) 210 return 0; 211 if (file2 == path2) 212 memcpy(pathbuf, ".", 2); 213 else { 214 memcpy(pathbuf, path2, file2 - path2); 215 pathbuf[file2 - path2] = '\0'; 216 } 217 if (stat(pathbuf, &sb2) != 0) 218 return 0; 219 return sb1.st_dev == sb2.st_dev && sb1.st_ino == sb2.st_ino; 220 } 221 222 static int 223 linkit(const char *source, const char *target, int isdir) 224 { 225 struct stat sb; 226 const char *p; 227 int ch, exists, first; 228 char path[PATH_MAX]; 229 char wbuf[PATH_MAX]; 230 char bbuf[PATH_MAX]; 231 232 if (!sflag) { 233 /* If source doesn't exist, quit now. */ 234 if ((Pflag ? lstat : stat)(source, &sb)) { 235 warn("%s", source); 236 return (1); 237 } 238 /* Only symbolic links to directories. */ 239 if (S_ISDIR(sb.st_mode)) { 240 errno = EISDIR; 241 warn("%s", source); 242 return (1); 243 } 244 } 245 246 /* 247 * If the target is a directory (and not a symlink if hflag), 248 * append the source's name. 249 */ 250 if (isdir || 251 (lstat(target, &sb) == 0 && S_ISDIR(sb.st_mode)) || 252 (!hflag && stat(target, &sb) == 0 && S_ISDIR(sb.st_mode))) { 253 if (strlcpy(bbuf, source, sizeof(bbuf)) >= sizeof(bbuf) || 254 (p = basename(bbuf)) == NULL || 255 snprintf(path, sizeof(path), "%s/%s", target, p) >= 256 (ssize_t)sizeof(path)) { 257 errno = ENAMETOOLONG; 258 warn("%s", source); 259 return (1); 260 } 261 target = path; 262 } 263 264 /* 265 * If the link source doesn't exist, and a symbolic link was 266 * requested, and -w was specified, give a warning. 267 */ 268 if (sflag && wflag) { 269 if (*source == '/') { 270 /* Absolute link source. */ 271 if (stat(source, &sb) != 0) 272 warn("warning: %s inaccessible", source); 273 } else { 274 /* 275 * Relative symlink source. Try to construct the 276 * absolute path of the source, by appending `source' 277 * to the parent directory of the target. 278 */ 279 strlcpy(bbuf, target, sizeof(bbuf)); 280 p = dirname(bbuf); 281 if (p != NULL) { 282 (void)snprintf(wbuf, sizeof(wbuf), "%s/%s", 283 p, source); 284 if (stat(wbuf, &sb) != 0) 285 warn("warning: %s", source); 286 } 287 } 288 } 289 290 /* 291 * If the file exists, first check it is not the same directory entry. 292 */ 293 exists = !lstat(target, &sb); 294 if (exists) { 295 if (!sflag && samedirent(source, target)) { 296 warnx("%s and %s are the same directory entry", 297 source, target); 298 return (1); 299 } 300 } 301 /* 302 * Then unlink it forcibly if -f was specified 303 * and interactively if -i was specified. 304 */ 305 if (fflag && exists) { 306 if (Fflag && S_ISDIR(sb.st_mode)) { 307 if (rmdir(target)) { 308 warn("%s", target); 309 return (1); 310 } 311 } else if (unlink(target)) { 312 warn("%s", target); 313 return (1); 314 } 315 } else if (iflag && exists) { 316 fflush(stdout); 317 fprintf(stderr, "replace %s? ", target); 318 319 first = ch = getchar(); 320 while(ch != '\n' && ch != EOF) 321 ch = getchar(); 322 if (first != 'y' && first != 'Y') { 323 fprintf(stderr, "not replaced\n"); 324 return (1); 325 } 326 327 if (Fflag && S_ISDIR(sb.st_mode)) { 328 if (rmdir(target)) { 329 warn("%s", target); 330 return (1); 331 } 332 } else if (unlink(target)) { 333 warn("%s", target); 334 return (1); 335 } 336 } 337 338 /* Attempt the link. */ 339 if (sflag ? symlink(source, target) : 340 linkat(AT_FDCWD, source, AT_FDCWD, target, 341 Pflag ? 0 : AT_SYMLINK_FOLLOW)) { 342 warn("%s", target); 343 return (1); 344 } 345 if (vflag) 346 (void)printf("%s %c> %s\n", target, linkch, source); 347 return (0); 348 } 349 350 static void 351 usage(void) 352 { 353 (void)fprintf(stderr, "%s\n%s\n%s\n", 354 "usage: ln [-s [-F] | -L | -P] [-f | -i] [-hnv] source_file [target_file]", 355 " ln [-s [-F] | -L | -P] [-f | -i] [-hnv] source_file ... target_dir", 356 " link source_file target_file"); 357 exit(1); 358 } 359