commands/ash/cd.c

   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  * 4. Neither the name of the University nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 #ifndef lint
  34 #if 0
  35 static char sccsid[] = "@(#)cd.c        8.2 (Berkeley) 5/4/95";
  36 #endif
  37 #endif /* not lint */
  38 /*
  39 #include <sys/cdefs.h>
  40 __FBSDID("$FreeBSD: src/bin/sh/cd.c,v 1.34 2004/04/06 20:06:51 markm Exp $");
  41 */
  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 #include <limits.h>
  50
  51 /*
  52  * The cd and pwd commands.
  53  */
  54
  55 #include "shell.h"
  56 #include "var.h"
  57 #include "nodes.h"      /* for jobs.h */
  58 #include "jobs.h"
  59 #include "options.h"
  60 #include "output.h"
  61 #include "memalloc.h"
  62 #include "error.h"
  63 #include "exec.h"
  64 #include "redir.h"
  65 #include "mystring.h"
  66 #include "builtins.h"
  67 #include "show.h"
  68 #include "cd.h"
  69
  70 STATIC int cdlogical(const char *);
  71 STATIC int cdphysical(const char *);
  72 STATIC int docd(const char *, int, int);
  73 STATIC char *getcomponent(void);
  74 STATIC int updatepwd(const char *);
  75
  76 STATIC char *curdir = NULL;     /* current working directory */
  77 STATIC char *prevdir;           /* previous working directory */
  78 STATIC char *cdcomppath;
  79
  80 int
  81 cdcmd(int argc, char **argv)
  82 {
  83         char *dest;
  84         char *path;
  85         char *p;
  86         struct stat statb;
  87         int ch, phys, print = 0;
  88
  89         optreset = 1; optind = 1; opterr = 0; /* initialize getopt */
  90         phys = Pflag;
  91         while ((ch = getopt(argc, argv, "LP")) != -1) {
  92                 switch (ch) {
  93                 case 'L':
  94                         phys = 0;
  95                         break;
  96                 case 'P':
  97                         phys = 1;
  98                         break;
  99                 default:
 100                         error("unknown option: -%c", optopt);
 101                         break;
 102                 }
 103         }
 104         argc -= optind;
 105         argv += optind;
 106
 107         if (argc > 1)
 108                 error("too many arguments");
 109
 110         if ((dest = *argv) == NULL && (dest = bltinlookup("HOME", 1)) == NULL)
 111                 error("HOME not set");
 112         if (*dest == '\0')
 113                 dest = ".";
 114         if (dest[0] == '-' && dest[1] == '\0') {
 115                 dest = prevdir ? prevdir : curdir;
 116                 if (dest)
 117                         print = 1;
 118                 else
 119                         dest = ".";
 120         }
 121         if (*dest == '/' || (path = bltinlookup("CDPATH", 1)) == NULL)
 122                 path = nullstr;
 123         while ((p = padvance(&path, dest)) != NULL) {
 124                 if (stat(p, &statb) >= 0 && S_ISDIR(statb.st_mode)) {
 125                         if (!print) {
 126                                 /*
 127                                  * XXX - rethink
 128                                  */
 129                                 if (p[0] == '.' && p[1] == '/' && p[2] != '\0')
 130                                         p += 2;
 131                                 print = strcmp(p, dest);
 132                         }
 133                         if (docd(p, print, phys) >= 0)
 134                                 return 0;
 135                 }
 136         }
 137         error("can't cd to %s", dest);
 138         /*NOTREACHED*/
 139         return 0;
 140 }
 141
 142
 143 /*
 144  * Actually change the directory.  In an interactive shell, print the
 145  * directory name if "print" is nonzero.
 146  */
 147 STATIC int
 148 docd(const char *dest, int print, int phys)
 149 {
 150
 151         TRACE(("docd(\"%s\", %d, %d) called\n", dest, print, phys));
 152
 153         /* If logical cd fails, fall back to physical. */
 154         if ((phys || cdlogical(dest) < 0) && cdphysical(dest) < 0)
 155                 return (-1);
 156
 157         if (print && iflag && curdir)
 158                 out1fmt("%s\n", curdir);
 159
 160         return 0;
 161 }
 162
 163 STATIC int
 164 cdlogical(const char *dest)
 165 {
 166         char *p;
 167         char *q;
 168         char *component;
 169         struct stat statb;
 170         int first;
 171         int badstat;
 172
 173         /*
 174          *  Check each component of the path. If we find a symlink or
 175          *  something we can't stat, clear curdir to force a getcwd()
 176          *  next time we get the value of the current directory.
 177          */
 178         badstat = 0;
 179         cdcomppath = stalloc(strlen(dest) + 1);
 180         scopy(dest, cdcomppath);
 181         STARTSTACKSTR(p);
 182         if (*dest == '/') {
 183                 STPUTC('/', p);
 184                 cdcomppath++;
 185         }
 186         first = 1;
 187         while ((q = getcomponent()) != NULL) {
 188                 if (q[0] == '\0' || (q[0] == '.' && q[1] == '\0'))
 189                         continue;
 190                 if (! first)
 191                         STPUTC('/', p);
 192                 first = 0;
 193                 component = q;
 194                 while (*q)
 195                         STPUTC(*q++, p);
 196                 if (equal(component, ".."))
 197                         continue;
 198                 STACKSTRNUL(p);
 199                 if (lstat(stackblock(), &statb) < 0) {
 200                         badstat = 1;
 201                         break;
 202                 }
 203         }
 204
 205         INTOFF;
 206         if (updatepwd(badstat ? NULL : dest) < 0 || chdir(curdir) < 0) {
 207                 INTON;
 208                 return (-1);
 209         }
 210         INTON;
 211         return (0);
 212 }
 213
 214 STATIC int
 215 cdphysical(const char *dest)
 216 {
 217
 218         INTOFF;
 219         if (chdir(dest) < 0 || updatepwd(NULL) < 0) {
 220                 INTON;
 221                 return (-1);
 222         }
 223         INTON;
 224         return (0);
 225 }
 226
 227 /*
 228  * Get the next component of the path name pointed to by cdcomppath.
 229  * This routine overwrites the string pointed to by cdcomppath.
 230  */
 231 STATIC char *
 232 getcomponent(void)
 233 {
 234         char *p;
 235         char *start;
 236
 237         if ((p = cdcomppath) == NULL)
 238                 return NULL;
 239         start = cdcomppath;
 240         while (*p != '/' && *p != '\0')
 241                 p++;
 242         if (*p == '\0') {
 243                 cdcomppath = NULL;
 244         } else {
 245                 *p++ = '\0';
 246                 cdcomppath = p;
 247         }
 248         return start;
 249 }
 250
 251
 252 /*
 253  * Update curdir (the name of the current directory) in response to a
 254  * cd command.  We also call hashcd to let the routines in exec.c know
 255  * that the current directory has changed.
 256  */
 257 STATIC int
 258 updatepwd(const char *dir)
 259 {
 260         char *new;
 261         char *p;
 262
 263         hashcd();                               /* update command hash table */
 264
 265         /*
 266          * If our argument is NULL, we don't know the current directory
 267          * any more because we traversed a symbolic link or something
 268          * we couldn't stat().
 269          */
 270         if (dir == NULL || curdir == NULL)  {
 271                 if (prevdir)
 272                         ckfree(prevdir);
 273                 INTOFF;
 274                 prevdir = curdir;
 275                 curdir = NULL;
 276                 if (getpwd() == NULL) {
 277                         INTON;
 278                         return (-1);
 279                 }
 280                 setvar("PWD", curdir, VEXPORT);
 281                 setvar("OLDPWD", prevdir, VEXPORT);
 282                 INTON;
 283                 return (0);
 284         }
 285         cdcomppath = stalloc(strlen(dir) + 1);
 286         scopy(dir, cdcomppath);
 287         STARTSTACKSTR(new);
 288         if (*dir != '/') {
 289                 p = curdir;
 290                 while (*p)
 291                         STPUTC(*p++, new);
 292                 if (p[-1] == '/')
 293                         STUNPUTC(new);
 294         }
 295         while ((p = getcomponent()) != NULL) {
 296                 if (equal(p, "..")) {
 297                         while (new > stackblock() && (STUNPUTC(new), *new) != '/');
 298                 } else if (*p != '\0' && ! equal(p, ".")) {
 299                         STPUTC('/', new);
 300                         while (*p)
 301                                 STPUTC(*p++, new);
 302                 }
 303         }
 304         if (new == stackblock())
 305                 STPUTC('/', new);
 306         STACKSTRNUL(new);
 307         INTOFF;
 308         if (prevdir)
 309                 ckfree(prevdir);
 310         prevdir = curdir;
 311         curdir = savestr(stackblock());
 312         setvar("PWD", curdir, VEXPORT);
 313         setvar("OLDPWD", prevdir, VEXPORT);
 314         INTON;
 315
 316         return (0);
 317 }
 318
 319 int
 320 pwdcmd(int argc, char **argv)
 321 {
 322         char buf[PATH_MAX];
 323         int ch, phys;
 324
 325         optreset = 1; optind = 1; opterr = 0; /* initialize getopt */
 326         phys = Pflag;
 327         while ((ch = getopt(argc, argv, "LP")) != -1) {
 328                 switch (ch) {
 329                 case 'L':
 330                         phys = 0;
 331                         break;
 332                 case 'P':
 333                         phys = 1;
 334                         break;
 335                 default:
 336                         error("unknown option: -%c", optopt);
 337                         break;
 338                 }
 339         }
 340         argc -= optind;
 341         argv += optind;
 342
 343         if (argc != 0)
 344                 error("too many arguments");
 345
 346         if (!phys && getpwd()) {
 347                 out1str(curdir);
 348                 out1c('\n');
 349         } else {
 350                 if (getcwd(buf, sizeof(buf)) == NULL)
 351                         error(".: %s", strerror(errno));
 352                 out1str(buf);
 353                 out1c('\n');
 354         }
 355
 356         return 0;
 357 }
 358
 359 /*
 360  * Find out what the current directory is. If we already know the current
 361  * directory, this routine returns immediately.
 362  */
 363 char *
 364 getpwd(void)
 365 {
 366         char buf[PATH_MAX];
 367
 368         if (curdir)
 369                 return curdir;
 370         if (getcwd(buf, sizeof(buf)) == NULL) {
 371                 char *pwd = getenv("PWD");
 372                 struct stat stdot, stpwd;
 373
 374                 if (pwd && *pwd == '/' && stat(".", &stdot) != -1 &&
 375                     stat(pwd, &stpwd) != -1 &&
 376                     stdot.st_dev == stpwd.st_dev &&
 377                     stdot.st_ino == stpwd.st_ino) {
 378                         curdir = savestr(pwd);
 379                         return curdir;
 380                 }
 381                 return NULL;
 382         }
 383         curdir = savestr(buf);
 384
 385         return curdir;
 386 }
 387
 388 /*
 389  * $PchId: cd.c,v 1.6 2006/05/22 12:42:03 philip Exp $
 390  */