cd.c revision 20425
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 * $Id: cd.c,v 1.6 1996/09/01 10:19:47 peter Exp $ 37 */ 38 39#ifndef lint 40static char const sccsid[] = "@(#)cd.c 8.2 (Berkeley) 5/4/95"; 41#endif /* not lint */ 42 43#include <sys/types.h> 44#include <sys/stat.h> 45#include <stdlib.h> 46#include <string.h> 47#include <unistd.h> 48#include <errno.h> 49 50/* 51 * The cd and pwd commands. 52 */ 53 54#include "shell.h" 55#include "var.h" 56#include "nodes.h" /* for jobs.h */ 57#include "jobs.h" 58#include "options.h" 59#include "output.h" 60#include "memalloc.h" 61#include "error.h" 62#include "exec.h" 63#include "redir.h" 64#include "mystring.h" 65#include "show.h" 66#include "cd.h" 67 68STATIC int docd __P((char *, int)); 69STATIC char *getcomponent __P((void)); 70STATIC void updatepwd __P((char *)); 71 72char *curdir = NULL; /* current working directory */ 73char *prevdir; /* previous working directory */ 74STATIC char *cdcomppath; 75 76int 77cdcmd(argc, argv) 78 int argc; 79 char **argv; 80{ 81 char *dest; 82 char *path; 83 char *p; 84 struct stat statb; 85 int print = 0; 86 87 nextopt(nullstr); 88 if ((dest = *argptr) == NULL && (dest = bltinlookup("HOME", 1)) == NULL) 89 error("HOME not set"); 90 if (*dest == '\0') 91 dest = "."; 92 if (dest[0] == '-' && dest[1] == '\0') { 93 dest = prevdir ? prevdir : curdir; 94 if (dest) 95 print = 1; 96 else 97 dest = "."; 98 } 99 if (*dest == '/' || (path = bltinlookup("CDPATH", 1)) == NULL) 100 path = nullstr; 101 while ((p = padvance(&path, dest)) != NULL) { 102 if (stat(p, &statb) >= 0 && S_ISDIR(statb.st_mode)) { 103 if (!print) { 104 /* 105 * XXX - rethink 106 */ 107 if (p[0] == '.' && p[1] == '/') 108 p += 2; 109 print = strcmp(p, dest); 110 } 111 if (docd(p, print) >= 0) 112 return 0; 113 114 } 115 } 116 error("can't cd to %s", dest); 117 /*NOTREACHED*/ 118 return 0; 119} 120 121 122/* 123 * Actually do the chdir. If the name refers to symbolic links, we 124 * compute the actual directory name before doing the cd. In an 125 * interactive shell, print the directory name if "print" is nonzero 126 * or if the name refers to a symbolic link. We also print the name 127 * if "/u/logname" was expanded in it, since this is similar to a 128 * symbolic link. (The check for this breaks if the user gives the 129 * cd command some additional, unused arguments.) 130 */ 131 132#if SYMLINKS == 0 133STATIC int 134docd(dest, print) 135 char *dest; 136 int print; 137{ 138 139 TRACE(("docd(\"%s\", %d) called\n", dest, print)); 140 INTOFF; 141 if (chdir(dest) < 0) { 142 INTON; 143 return -1; 144 } 145 updatepwd(dest); 146 INTON; 147 if (print && iflag) 148 out1fmt("%s\n", stackblock()); 149 return 0; 150} 151 152#else 153 154 155 156STATIC int 157docd(dest, print) 158 char *dest; 159 int print; 160{ 161 register char *p; 162 register char *q; 163 char *symlink; 164 char *component; 165 struct stat statb; 166 int first; 167 int i; 168 169 TRACE(("docd(\"%s\", %d) called\n", dest, print)); 170 171top: 172 cdcomppath = dest; 173 STARTSTACKSTR(p); 174 if (*dest == '/') { 175 STPUTC('/', p); 176 cdcomppath++; 177 } 178 first = 1; 179 while ((q = getcomponent()) != NULL) { 180 if (q[0] == '\0' || (q[0] == '.' && q[1] == '\0')) 181 continue; 182 if (! first) 183 STPUTC('/', p); 184 first = 0; 185 component = q; 186 while (*q) 187 STPUTC(*q++, p); 188 if (equal(component, "..")) 189 continue; 190 STACKSTRNUL(p); 191 if (lstat(stackblock(), &statb) < 0) 192 error("lstat %s failed", stackblock()); 193 if (!S_ISLNK(statb.st_mode)) 194 continue; 195 196 /* Hit a symbolic link. We have to start all over again. */ 197 print = 1; 198 STPUTC('\0', p); 199 symlink = grabstackstr(p); 200 i = (int)statb.st_size + 2; /* 2 for '/' and '\0' */ 201 if (cdcomppath != NULL) 202 i += strlen(cdcomppath); 203 p = stalloc(i); 204 if (readlink(symlink, p, (int)statb.st_size) < 0) { 205 error("readlink %s failed", stackblock()); 206 } 207 if (cdcomppath != NULL) { 208 p[(int)statb.st_size] = '/'; 209 scopy(cdcomppath, p + (int)statb.st_size + 1); 210 } else { 211 p[(int)statb.st_size] = '\0'; 212 } 213 if (p[0] != '/') { /* relative path name */ 214 char *r; 215 q = r = symlink; 216 while (*q) { 217 if (*q++ == '/') 218 r = q; 219 } 220 *r = '\0'; 221 dest = stalloc(strlen(symlink) + strlen(p) + 1); 222 scopy(symlink, dest); 223 strcat(dest, p); 224 } else { 225 dest = p; 226 } 227 goto top; 228 } 229 STPUTC('\0', p); 230 p = grabstackstr(p); 231 INTOFF; 232 if (chdir(*p ? p : ".") < 0) { 233 INTON; 234 return -1; 235 } 236 updatepwd(p); 237 INTON; 238 if (print && iflag) 239 out1fmt("%s\n", p); 240 return 0; 241} 242#endif /* SYMLINKS */ 243 244 245 246/* 247 * Get the next component of the path name pointed to by cdcomppath. 248 * This routine overwrites the string pointed to by cdcomppath. 249 */ 250 251STATIC char * 252getcomponent() { 253 register char *p; 254 char *start; 255 256 if ((p = cdcomppath) == NULL) 257 return NULL; 258 start = cdcomppath; 259 while (*p != '/' && *p != '\0') 260 p++; 261 if (*p == '\0') { 262 cdcomppath = NULL; 263 } else { 264 *p++ = '\0'; 265 cdcomppath = p; 266 } 267 return start; 268} 269 270 271 272/* 273 * Update curdir (the name of the current directory) in response to a 274 * cd command. We also call hashcd to let the routines in exec.c know 275 * that the current directory has changed. 276 */ 277 278void hashcd(); 279 280STATIC void 281updatepwd(dir) 282 char *dir; 283 { 284 char *new; 285 char *p; 286 287 hashcd(); /* update command hash table */ 288 cdcomppath = stalloc(strlen(dir) + 1); 289 scopy(dir, cdcomppath); 290 STARTSTACKSTR(new); 291 if (*dir != '/') { 292 if (curdir == NULL) 293 return; 294 p = curdir; 295 while (*p) 296 STPUTC(*p++, new); 297 if (p[-1] == '/') 298 STUNPUTC(new); 299 } 300 while ((p = getcomponent()) != NULL) { 301 if (equal(p, "..")) { 302 while (new > stackblock() && (STUNPUTC(new), *new) != '/'); 303 } else if (*p != '\0' && ! equal(p, ".")) { 304 STPUTC('/', new); 305 while (*p) 306 STPUTC(*p++, new); 307 } 308 } 309 if (new == stackblock()) 310 STPUTC('/', new); 311 STACKSTRNUL(new); 312 INTOFF; 313 if (prevdir) 314 ckfree(prevdir); 315 prevdir = curdir; 316 curdir = savestr(stackblock()); 317 INTON; 318} 319 320 321 322int 323pwdcmd(argc, argv) 324 int argc; 325 char **argv; 326{ 327 getpwd(); 328 out1str(curdir); 329 out1c('\n'); 330 return 0; 331} 332 333 334 335 336#define MAXPWD 256 337 338/* 339 * Run /bin/pwd to find out what the current directory is. We suppress 340 * interrupts throughout most of this, but the user can still break out 341 * of it by killing the pwd program. If we already know the current 342 * directory, this routine returns immediately. 343 */ 344void 345getpwd() 346{ 347 char buf[MAXPWD]; 348 char *p; 349 int i; 350 int status; 351 struct job *jp; 352 int pip[2]; 353 char *pwd_bin = "/bin/pwd"; 354 355 if (curdir) 356 return; 357 INTOFF; 358 if (pipe(pip) < 0) 359 error("Pipe call failed"); 360 /* make a fall-back guess, otherwise we're simply screwed */ 361 if (access(pwd_bin, X_OK) == -1) 362 pwd_bin = "/stand/pwd"; 363 jp = makejob((union node *)NULL, 1); 364 if (forkshell(jp, (union node *)NULL, FORK_NOJOB) == 0) { 365 close(pip[0]); 366 if (pip[1] != 1) { 367 close(1); 368 copyfd(pip[1], 1); 369 close(pip[1]); 370 } 371 (void) execl(pwd_bin, "pwd", (char *)0); 372 error("Cannot exec %s", pwd_bin); 373 } 374 (void) close(pip[1]); 375 pip[1] = -1; 376 p = buf; 377 while ((i = read(pip[0], p, buf + MAXPWD - p)) > 0 378 || (i == -1 && errno == EINTR)) { 379 if (i > 0) 380 p += i; 381 } 382 (void) close(pip[0]); 383 pip[0] = -1; 384 status = waitforjob(jp); 385 if (status != 0) 386 error((char *)0); 387 if (i < 0 || p == buf || p[-1] != '\n') 388 error("pwd command failed"); 389 p[-1] = '\0'; 390 curdir = savestr(buf); 391 INTON; 392} 393