1 /*- 2 * Copyright (c) 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * 5 * This code is derived from software contributed to Berkeley by 6 * Kenneth Almquist. 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. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by the University of 19 * California, Berkeley and its contributors. 20 * 4. Neither the name of the University nor the names of its contributors 21 * may be used to endorse or promote products derived from this software 22 * without specific prior written permission. 23 * 24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 34 * SUCH DAMAGE. 35 */ 36 37 #ifndef lint 38 #if 0 39 static char sccsid[] = "@(#)cd.c 8.2 (Berkeley) 5/4/95"; 40 #endif 41 static const char rcsid[] = 42 "$FreeBSD$"; 43 #endif /* not lint */ 44 45 #include <sys/types.h> 46 #include <sys/stat.h> 47 #include <stdlib.h> 48 #include <string.h> 49 #include <unistd.h> 50 #include <errno.h> 51 52 /* 53 * The cd and pwd commands. 54 */ 55 56 #include "shell.h" 57 #include "var.h" 58 #include "nodes.h" /* for jobs.h */ 59 #include "jobs.h" 60 #include "options.h" 61 #include "output.h" 62 #include "memalloc.h" 63 #include "error.h" 64 #include "exec.h" 65 #include "redir.h" 66 #include "mystring.h" 67 #include "show.h" 68 #include "cd.h" 69 70 STATIC int docd __P((char *, int)); 71 STATIC char *getcomponent __P((void)); 72 STATIC void updatepwd __P((char *)); 73 74 char *curdir = NULL; /* current working directory */ 75 char *prevdir; /* previous working directory */ 76 STATIC char *cdcomppath; 77 78 int 79 cdcmd(argc, argv) 80 int argc __unused; 81 char **argv __unused; 82 { 83 char *dest; 84 char *path; 85 char *p; 86 struct stat statb; 87 int print = 0; 88 89 nextopt(nullstr); 90 if ((dest = *argptr) == NULL && (dest = bltinlookup("HOME", 1)) == NULL) 91 error("HOME not set"); 92 if (*dest == '\0') 93 dest = "."; 94 if (dest[0] == '-' && dest[1] == '\0') { 95 dest = prevdir ? prevdir : curdir; 96 if (dest) 97 print = 1; 98 else 99 dest = "."; 100 } 101 if (*dest == '/' || (path = bltinlookup("CDPATH", 1)) == NULL) 102 path = nullstr; 103 while ((p = padvance(&path, dest)) != NULL) { 104 if (stat(p, &statb) >= 0 && S_ISDIR(statb.st_mode)) { 105 if (!print) { 106 /* 107 * XXX - rethink 108 */ 109 if (p[0] == '.' && p[1] == '/' && p[2] != '\0') 110 p += 2; 111 print = strcmp(p, dest); 112 } 113 if (docd(p, print) >= 0) 114 return 0; 115 116 } 117 } 118 error("can't cd to %s", dest); 119 /*NOTREACHED*/ 120 return 0; 121 } 122 123 124 /* 125 * Actually do the chdir. In an interactive shell, print the 126 * directory name if "print" is nonzero. 127 */ 128 STATIC int 129 docd(dest, print) 130 char *dest; 131 int print; 132 { 133 char *p; 134 char *q; 135 char *component; 136 struct stat statb; 137 int first; 138 int badstat; 139 140 TRACE(("docd(\"%s\", %d) called\n", dest, print)); 141 142 /* 143 * Check each component of the path. If we find a symlink or 144 * something we can't stat, clear curdir to force a getcwd() 145 * next time we get the value of the current directory. 146 */ 147 badstat = 0; 148 cdcomppath = stalloc(strlen(dest) + 1); 149 scopy(dest, cdcomppath); 150 STARTSTACKSTR(p); 151 if (*dest == '/') { 152 STPUTC('/', p); 153 cdcomppath++; 154 } 155 first = 1; 156 while ((q = getcomponent()) != NULL) { 157 if (q[0] == '\0' || (q[0] == '.' && q[1] == '\0')) 158 continue; 159 if (! first) 160 STPUTC('/', p); 161 first = 0; 162 component = q; 163 while (*q) 164 STPUTC(*q++, p); 165 if (equal(component, "..")) 166 continue; 167 STACKSTRNUL(p); 168 if ((lstat(stackblock(), &statb) < 0) 169 || (S_ISLNK(statb.st_mode))) { 170 /* print = 1; */ 171 badstat = 1; 172 break; 173 } 174 } 175 176 INTOFF; 177 if (chdir(dest) < 0) { 178 INTON; 179 return -1; 180 } 181 updatepwd(badstat ? NULL : dest); 182 INTON; 183 if (print && iflag && curdir) 184 out1fmt("%s\n", curdir); 185 return 0; 186 } 187 188 189 /* 190 * Get the next component of the path name pointed to by cdcomppath. 191 * This routine overwrites the string pointed to by cdcomppath. 192 */ 193 STATIC char * 194 getcomponent() 195 { 196 char *p; 197 char *start; 198 199 if ((p = cdcomppath) == NULL) 200 return NULL; 201 start = cdcomppath; 202 while (*p != '/' && *p != '\0') 203 p++; 204 if (*p == '\0') { 205 cdcomppath = NULL; 206 } else { 207 *p++ = '\0'; 208 cdcomppath = p; 209 } 210 return start; 211 } 212 213 214 /* 215 * Update curdir (the name of the current directory) in response to a 216 * cd command. We also call hashcd to let the routines in exec.c know 217 * that the current directory has changed. 218 */ 219 STATIC void 220 updatepwd(dir) 221 char *dir; 222 { 223 char *new; 224 char *p; 225 226 hashcd(); /* update command hash table */ 227 228 /* 229 * If our argument is NULL, we don't know the current directory 230 * any more because we traversed a symbolic link or something 231 * we couldn't stat(). 232 */ 233 if (dir == NULL || curdir == NULL) { 234 if (prevdir) 235 ckfree(prevdir); 236 INTOFF; 237 prevdir = curdir; 238 curdir = NULL; 239 if (getpwd() == NULL) 240 error("getcwd() failed: %s", strerror(errno)); 241 setvar("PWD", curdir, VEXPORT | VTEXTFIXED); 242 setvar("OLDPWD", prevdir, VEXPORT | VTEXTFIXED); 243 INTON; 244 return; 245 } 246 cdcomppath = stalloc(strlen(dir) + 1); 247 scopy(dir, cdcomppath); 248 STARTSTACKSTR(new); 249 if (*dir != '/') { 250 p = curdir; 251 while (*p) 252 STPUTC(*p++, new); 253 if (p[-1] == '/') 254 STUNPUTC(new); 255 } 256 while ((p = getcomponent()) != NULL) { 257 if (equal(p, "..")) { 258 while (new > stackblock() && (STUNPUTC(new), *new) != '/'); 259 } else if (*p != '\0' && ! equal(p, ".")) { 260 STPUTC('/', new); 261 while (*p) 262 STPUTC(*p++, new); 263 } 264 } 265 if (new == stackblock()) 266 STPUTC('/', new); 267 STACKSTRNUL(new); 268 INTOFF; 269 if (prevdir) 270 ckfree(prevdir); 271 prevdir = curdir; 272 curdir = savestr(stackblock()); 273 setvar("PWD", curdir, VEXPORT | VTEXTFIXED); 274 setvar("OLDPWD", prevdir, VEXPORT | VTEXTFIXED); 275 INTON; 276 } 277 278 279 int 280 pwdcmd(argc, argv) 281 int argc __unused; 282 char **argv __unused; 283 { 284 if (!getpwd()) 285 error("getcwd() failed: %s", strerror(errno)); 286 out1str(curdir); 287 out1c('\n'); 288 return 0; 289 } 290 291 292 293 294 #define MAXPWD 256 295 296 /* 297 * Find out what the current directory is. If we already know the current 298 * directory, this routine returns immediately. 299 */ 300 char * 301 getpwd() 302 { 303 char buf[MAXPWD]; 304 305 if (curdir) 306 return curdir; 307 /* 308 * Things are a bit complicated here; we could have just used 309 * getcwd, but traditionally getcwd is implemented using popen 310 * to /bin/pwd. This creates a problem for us, since we cannot 311 * keep track of the job if it is being ran behind our backs. 312 * So we re-implement getcwd(), and we suppress interrupts 313 * throughout the process. This is not completely safe, since 314 * the user can still break out of it by killing the pwd program. 315 * We still try to use getcwd for systems that we know have a 316 * c implementation of getcwd, that does not open a pipe to 317 * /bin/pwd. 318 */ 319 #if defined(__NetBSD__) || defined(__FreeBSD__) || defined(__SVR4) 320 321 if (getcwd(buf, sizeof(buf)) == NULL) { 322 char *pwd = getenv("PWD"); 323 struct stat stdot, stpwd; 324 325 if (pwd && *pwd == '/' && stat(".", &stdot) != -1 && 326 stat(pwd, &stpwd) != -1 && 327 stdot.st_dev == stpwd.st_dev && 328 stdot.st_ino == stpwd.st_ino) { 329 curdir = savestr(pwd); 330 return curdir; 331 } 332 return NULL; 333 } 334 curdir = savestr(buf); 335 #else 336 { 337 char *p; 338 int i; 339 int status; 340 struct job *jp; 341 int pip[2]; 342 343 INTOFF; 344 if (pipe(pip) < 0) 345 error("Pipe call failed"); 346 jp = makejob((union node *)NULL, 1); 347 if (forkshell(jp, (union node *)NULL, FORK_NOJOB) == 0) { 348 (void) close(pip[0]); 349 if (pip[1] != 1) { 350 close(1); 351 copyfd(pip[1], 1); 352 close(pip[1]); 353 } 354 (void) execl("/bin/pwd", "pwd", (char *)0); 355 error("Cannot exec /bin/pwd"); 356 } 357 (void) close(pip[1]); 358 pip[1] = -1; 359 p = buf; 360 while ((i = read(pip[0], p, buf + MAXPWD - p)) > 0 361 || (i == -1 && errno == EINTR)) { 362 if (i > 0) 363 p += i; 364 } 365 (void) close(pip[0]); 366 pip[0] = -1; 367 status = waitforjob(jp); 368 if (status != 0) 369 error((char *)0); 370 if (i < 0 || p == buf || p[-1] != '\n') 371 error("pwd command failed"); 372 p[-1] = '\0'; 373 } 374 curdir = savestr(buf); 375 INTON; 376 #endif 377 return curdir; 378 } 379