1 /* $NetBSD: cd.c,v 1.23 1997/07/04 20:59:40 christos Exp $ */ 2 3 /*- 4 * Copyright (c) 1991, 1993 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software contributed to Berkeley by 8 * Kenneth Almquist. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 */ 38 39 #include <sys/cdefs.h> 40 #ifndef lint 41 #if 0 42 static char sccsid[] = "@(#)cd.c 8.2 (Berkeley) 5/4/95"; 43 #else 44 __RCSID("$NetBSD: cd.c,v 1.23 1997/07/04 20:59:40 christos Exp $"); 45 #endif 46 #endif /* not lint */ 47 48 #include <sys/types.h> 49 #include <sys/stat.h> 50 #include <stdlib.h> 51 #include <string.h> 52 #include <unistd.h> 53 #include <errno.h> 54 55 /* 56 * The cd and pwd commands. 57 */ 58 59 #include "shell.h" 60 #include "var.h" 61 #include "nodes.h" /* for jobs.h */ 62 #include "jobs.h" 63 #include "options.h" 64 #include "output.h" 65 #include "memalloc.h" 66 #include "error.h" 67 #include "exec.h" 68 #include "redir.h" 69 #include "mystring.h" 70 #include "show.h" 71 #include "cd.h" 72 73 STATIC int docd __P((char *, int)); 74 STATIC char *getcomponent __P((void)); 75 STATIC void updatepwd __P((char *)); 76 77 char *curdir = NULL; /* current working directory */ 78 char *prevdir; /* previous working directory */ 79 STATIC char *cdcomppath; 80 81 int 82 cdcmd(argc, argv) 83 int argc; 84 char **argv; 85 { 86 char *dest; 87 char *path; 88 char *p; 89 struct stat statb; 90 int print = 0; 91 92 nextopt(nullstr); 93 if ((dest = *argptr) == NULL && (dest = bltinlookup("HOME", 1)) == NULL) 94 error("HOME not set"); 95 if (*dest == '\0') 96 dest = "."; 97 if (dest[0] == '-' && dest[1] == '\0') { 98 dest = prevdir ? prevdir : curdir; 99 print = 1; 100 if (dest) 101 print = 1; 102 else 103 dest = "."; 104 } 105 if (*dest == '/' || (path = bltinlookup("CDPATH", 1)) == NULL) 106 path = nullstr; 107 while ((p = padvance(&path, dest)) != NULL) { 108 if (stat(p, &statb) >= 0 && S_ISDIR(statb.st_mode)) { 109 if (!print) { 110 /* 111 * XXX - rethink 112 */ 113 if (p[0] == '.' && p[1] == '/') 114 p += 2; 115 print = strcmp(p, dest); 116 } 117 if (docd(p, print) >= 0) 118 return 0; 119 120 } 121 } 122 error("can't cd to %s", dest); 123 /*NOTREACHED*/ 124 return 0; 125 } 126 127 128 /* 129 * Actually do the chdir. In an interactive shell, print the 130 * directory name if "print" is nonzero. 131 */ 132 133 STATIC int 134 docd(dest, print) 135 char *dest; 136 int print; 137 { 138 char *p; 139 char *q; 140 char *component; 141 struct stat statb; 142 int first; 143 int badstat; 144 145 TRACE(("docd(\"%s\", %d) called\n", dest, print)); 146 147 /* 148 * Check each component of the path. If we find a symlink or 149 * something we can't stat, clear curdir to force a getcwd() 150 * next time we get the value of the current directory. 151 */ 152 badstat = 0; 153 cdcomppath = stalloc(strlen(dest) + 1); 154 scopy(dest, cdcomppath); 155 STARTSTACKSTR(p); 156 if (*dest == '/') { 157 STPUTC('/', p); 158 cdcomppath++; 159 } 160 first = 1; 161 while ((q = getcomponent()) != NULL) { 162 if (q[0] == '\0' || (q[0] == '.' && q[1] == '\0')) 163 continue; 164 if (! first) 165 STPUTC('/', p); 166 first = 0; 167 component = q; 168 while (*q) 169 STPUTC(*q++, p); 170 if (equal(component, "..")) 171 continue; 172 STACKSTRNUL(p); 173 if ((lstat(stackblock(), &statb) < 0) 174 || (S_ISLNK(statb.st_mode))) { 175 /* print = 1; */ 176 badstat = 1; 177 break; 178 } 179 } 180 181 INTOFF; 182 if (chdir(dest) < 0) { 183 INTON; 184 return -1; 185 } 186 updatepwd(badstat ? NULL : dest); 187 INTON; 188 if (print && iflag && curdir) 189 out1fmt("%s\n", curdir); 190 return 0; 191 } 192 193 194 /* 195 * Get the next component of the path name pointed to by cdcomppath. 196 * This routine overwrites the string pointed to by cdcomppath. 197 */ 198 199 STATIC char * 200 getcomponent() { 201 char *p; 202 char *start; 203 204 if ((p = cdcomppath) == NULL) 205 return NULL; 206 start = cdcomppath; 207 while (*p != '/' && *p != '\0') 208 p++; 209 if (*p == '\0') { 210 cdcomppath = NULL; 211 } else { 212 *p++ = '\0'; 213 cdcomppath = p; 214 } 215 return start; 216 } 217 218 219 220 /* 221 * Update curdir (the name of the current directory) in response to a 222 * cd command. We also call hashcd to let the routines in exec.c know 223 * that the current directory has changed. 224 */ 225 226 STATIC void 227 updatepwd(dir) 228 char *dir; 229 { 230 char *new; 231 char *p; 232 233 hashcd(); /* update command hash table */ 234 235 /* 236 * If our argument is NULL, we don't know the current directory 237 * any more because we traversed a symbolic link or something 238 * we couldn't stat(). 239 */ 240 if (dir == NULL) { 241 if (prevdir) 242 ckfree(prevdir); 243 INTOFF; 244 prevdir = curdir; 245 curdir = NULL; 246 getpwd(); 247 INTON; 248 return; 249 } 250 251 cdcomppath = stalloc(strlen(dir) + 1); 252 scopy(dir, cdcomppath); 253 STARTSTACKSTR(new); 254 if (*dir != '/') { 255 if (curdir == NULL) 256 return; 257 p = curdir; 258 while (*p) 259 STPUTC(*p++, new); 260 if (p[-1] == '/') 261 STUNPUTC(new); 262 } 263 while ((p = getcomponent()) != NULL) { 264 if (equal(p, "..")) { 265 while (new > stackblock() && (STUNPUTC(new), *new) != '/'); 266 } else if (*p != '\0' && ! equal(p, ".")) { 267 STPUTC('/', new); 268 while (*p) 269 STPUTC(*p++, new); 270 } 271 } 272 if (new == stackblock()) 273 STPUTC('/', new); 274 STACKSTRNUL(new); 275 INTOFF; 276 if (prevdir) 277 ckfree(prevdir); 278 prevdir = curdir; 279 curdir = savestr(stackblock()); 280 setvar("PWD", curdir, VEXPORT|VTEXTFIXED); 281 INTON; 282 } 283 284 285 286 int 287 pwdcmd(argc, argv) 288 int argc; 289 char **argv; 290 { 291 getpwd(); 292 out1str(curdir); 293 out1c('\n'); 294 return 0; 295 } 296 297 298 299 300 #define MAXPWD 256 301 302 /* 303 * Find out what the current directory is. If we already know the current 304 * directory, this routine returns immediately. 305 */ 306 void 307 getpwd() 308 { 309 char buf[MAXPWD]; 310 311 if (curdir) 312 return; 313 /* 314 * Things are a bit complicated here; we could have just used 315 * getcwd, but traditionally getcwd is implemented using popen 316 * to /bin/pwd. This creates a problem for us, since we cannot 317 * keep track of the job if it is being ran behind our backs. 318 * So we re-implement getcwd(), and we suppress interrupts 319 * throughout the process. This is not completely safe, since 320 * the user can still break out of it by killing the pwd program. 321 * We still try to use getcwd for systems that we know have a 322 * c implementation of getcwd, that does not open a pipe to 323 * /bin/pwd. 324 */ 325 #if defined(__NetBSD__) || defined(__SVR4) 326 327 if (getcwd(buf, sizeof(buf)) == NULL) { 328 char *pwd = getenv("PWD"); 329 struct stat stdot, stpwd; 330 331 if (pwd && *pwd == '/' && stat(".", &stdot) != -1 && 332 stat(pwd, &stpwd) != -1 && 333 stdot.st_dev == stpwd.st_dev && 334 stdot.st_ino == stpwd.st_ino) { 335 curdir = savestr(pwd); 336 return; 337 } 338 error("getcwd() failed: %s", strerror(errno)); 339 } 340 curdir = savestr(buf); 341 #else 342 { 343 char *p; 344 int i; 345 int status; 346 struct job *jp; 347 int pip[2]; 348 349 INTOFF; 350 if (pipe(pip) < 0) 351 error("Pipe call failed"); 352 jp = makejob((union node *)NULL, 1); 353 if (forkshell(jp, (union node *)NULL, FORK_NOJOB) == 0) { 354 (void) close(pip[0]); 355 if (pip[1] != 1) { 356 close(1); 357 copyfd(pip[1], 1); 358 close(pip[1]); 359 } 360 (void) execl("/bin/pwd", "pwd", (char *)0); 361 error("Cannot exec /bin/pwd"); 362 } 363 (void) close(pip[1]); 364 pip[1] = -1; 365 p = buf; 366 while ((i = read(pip[0], p, buf + MAXPWD - p)) > 0 367 || (i == -1 && errno == EINTR)) { 368 if (i > 0) 369 p += i; 370 } 371 (void) close(pip[0]); 372 pip[0] = -1; 373 status = waitforjob(jp); 374 if (status != 0) 375 error((char *)0); 376 if (i < 0 || p == buf || p[-1] != '\n') 377 error("pwd command failed"); 378 p[-1] = '\0'; 379 } 380 curdir = savestr(buf); 381 INTON; 382 #endif 383 } 384