bin/sh/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 #include <sys/cdefs.h>
  39 __FBSDID("$FreeBSD$");
  40
  41 #include <sys/types.h>
  42 #include <sys/stat.h>
  43 #include <stdlib.h>
  44 #include <string.h>
  45 #include <unistd.h>
  46 #include <errno.h>
  47 #include <limits.h>
  48
  49 /*
  50  * The cd and pwd commands.
  51  */
  52
  53 #include "shell.h"
  54 #include "var.h"
  55 #include "nodes.h"      /* for jobs.h */
  56 #include "jobs.h"
  57 #include "options.h"
  58 #include "output.h"
  59 #include "memalloc.h"
  60 #include "error.h"
  61 #include "exec.h"
  62 #include "redir.h"
  63 #include "mystring.h"
  64 #include "show.h"
  65 #include "cd.h"
  66
  67 STATIC int cdlogical(char *);
  68 STATIC int cdphysical(char *);
  69 STATIC int docd(char *, int, int);
  70 STATIC char *getcomponent(void);
  71 STATIC char *findcwd(char *);
  72 STATIC void updatepwd(char *);
  73 STATIC char *getpwd2(char *, size_t);
  74
  75 STATIC char *curdir = NULL;     /* current working directory */
  76 STATIC char *prevdir;           /* previous working directory */
  77 STATIC char *cdcomppath;
  78
  79 int
  80 cdcmd(int argc, char **argv)
  81 {
  82         char *dest;
  83         char *path;
  84         char *p;
  85         struct stat statb;
  86         int ch, phys, print = 0;
  87
  88         optreset = 1; optind = 1; opterr = 0; /* initialize getopt */
  89         phys = Pflag;
  90         while ((ch = getopt(argc, argv, "LP")) != -1) {
  91                 switch (ch) {
  92                 case 'L':
  93                         phys = 0;
  94                         break;
  95                 case 'P':
  96                         phys = 1;
  97                         break;
  98                 default:
  99                         error("unknown option: -%c", optopt);
 100                         break;
 101                 }
 102         }
 103         argc -= optind;
 104         argv += optind;
 105
 106         if (argc > 1)
 107                 error("too many arguments");
 108
 109         if ((dest = *argv) == NULL && (dest = bltinlookup("HOME", 1)) == NULL)
 110                 error("HOME not set");
 111         if (*dest == '\0')
 112                 dest = ".";
 113         if (dest[0] == '-' && dest[1] == '\0') {
 114                 dest = prevdir ? prevdir : curdir;
 115                 if (dest)
 116                         print = 1;
 117                 else
 118                         dest = ".";
 119         }
 120         if (*dest == '/' || (path = bltinlookup("CDPATH", 1)) == NULL)
 121                 path = nullstr;
 122         while ((p = padvance(&path, dest)) != NULL) {
 123                 if (stat(p, &statb) >= 0 && S_ISDIR(statb.st_mode)) {
 124                         if (!print) {
 125                                 /*
 126                                  * XXX - rethink
 127                                  */
 128                                 if (p[0] == '.' && p[1] == '/' && p[2] != '\0')
 129                                         print = strcmp(p + 2, dest);
 130                                 else
 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(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(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 ((p = findcwd(badstat ? NULL : dest)) == NULL || chdir(p) < 0) {
 207                 INTON;
 208                 return (-1);
 209         }
 210         updatepwd(p);
 211         INTON;
 212         return (0);
 213 }
 214
 215 STATIC int
 216 cdphysical(char *dest)
 217 {
 218         char *p;
 219
 220         INTOFF;
 221         if (chdir(dest) < 0 || (p = findcwd(NULL)) == NULL) {
 222                 INTON;
 223                 return (-1);
 224         }
 225         updatepwd(p);
 226         INTON;
 227         return (0);
 228 }
 229
 230 /*
 231  * Get the next component of the path name pointed to by cdcomppath.
 232  * This routine overwrites the string pointed to by cdcomppath.
 233  */
 234 STATIC char *
 235 getcomponent(void)
 236 {
 237         char *p;
 238         char *start;
 239
 240         if ((p = cdcomppath) == NULL)
 241                 return NULL;
 242         start = cdcomppath;
 243         while (*p != '/' && *p != '\0')
 244                 p++;
 245         if (*p == '\0') {
 246                 cdcomppath = NULL;
 247         } else {
 248                 *p++ = '\0';
 249                 cdcomppath = p;
 250         }
 251         return start;
 252 }
 253
 254
 255 STATIC char *
 256 findcwd(char *dir)
 257 {
 258         char *new;
 259         char *p;
 260
 261         /*
 262          * If our argument is NULL, we don't know the current directory
 263          * any more because we traversed a symbolic link or something
 264          * we couldn't stat().
 265          */
 266         if (dir == NULL || curdir == NULL)  {
 267                 p = stalloc(PATH_MAX);
 268                 return getpwd2(p, PATH_MAX);
 269         }
 270         cdcomppath = stalloc(strlen(dir) + 1);
 271         scopy(dir, cdcomppath);
 272         STARTSTACKSTR(new);
 273         if (*dir != '/') {
 274                 p = curdir;
 275                 while (*p)
 276                         STPUTC(*p++, new);
 277                 if (p[-1] == '/')
 278                         STUNPUTC(new);
 279         }
 280         while ((p = getcomponent()) != NULL) {
 281                 if (equal(p, "..")) {
 282                         while (new > stackblock() && (STUNPUTC(new), *new) != '/');
 283                 } else if (*p != '\0' && ! equal(p, ".")) {
 284                         STPUTC('/', new);
 285                         while (*p)
 286                                 STPUTC(*p++, new);
 287                 }
 288         }
 289         if (new == stackblock())
 290                 STPUTC('/', new);
 291         STACKSTRNUL(new);
 292         return stackblock();
 293 }
 294
 295 /*
 296  * Update curdir (the name of the current directory) in response to a
 297  * cd command.  We also call hashcd to let the routines in exec.c know
 298  * that the current directory has changed.
 299  */
 300 STATIC void
 301 updatepwd(char *dir)
 302 {
 303         hashcd();                               /* update command hash table */
 304
 305         if (prevdir)
 306                 ckfree(prevdir);
 307         prevdir = curdir;
 308         curdir = savestr(dir);
 309         setvar("PWD", curdir, VEXPORT);
 310         setvar("OLDPWD", prevdir, VEXPORT);
 311 }
 312
 313 int
 314 pwdcmd(int argc, char **argv)
 315 {
 316         char buf[PATH_MAX];
 317         int ch, phys;
 318
 319         optreset = 1; optind = 1; opterr = 0; /* initialize getopt */
 320         phys = Pflag;
 321         while ((ch = getopt(argc, argv, "LP")) != -1) {
 322                 switch (ch) {
 323                 case 'L':
 324                         phys = 0;
 325                         break;
 326                 case 'P':
 327                         phys = 1;
 328                         break;
 329                 default:
 330                         error("unknown option: -%c", optopt);
 331                         break;
 332                 }
 333         }
 334         argc -= optind;
 335         argv += optind;
 336
 337         if (argc != 0)
 338                 error("too many arguments");
 339
 340         if (!phys && getpwd()) {
 341                 out1str(curdir);
 342                 out1c('\n');
 343         } else {
 344                 if (getcwd(buf, sizeof(buf)) == NULL)
 345                         error(".: %s", strerror(errno));
 346                 out1str(buf);
 347                 out1c('\n');
 348         }
 349
 350         return 0;
 351 }
 352
 353 /*
 354  * Get the current directory and cache the result in curdir.
 355  */
 356 char *
 357 getpwd(void)
 358 {
 359         char buf[PATH_MAX];
 360         char *p;
 361
 362         if (curdir)
 363                 return curdir;
 364
 365         p = getpwd2(buf, sizeof(buf));
 366         if (p != NULL)
 367                 curdir = savestr(p);
 368
 369         return curdir;
 370 }
 371
 372 /*
 373  * Return the current directory.
 374  */
 375 STATIC char *
 376 getpwd2(char *buf, size_t size)
 377 {
 378         if (getcwd(buf, size) == NULL) {
 379                 char *pwd = getenv("PWD");
 380                 struct stat stdot, stpwd;
 381
 382                 if (pwd && *pwd == '/' && stat(".", &stdot) != -1 &&
 383                     stat(pwd, &stpwd) != -1 &&
 384                     stdot.st_dev == stpwd.st_dev &&
 385                     stdot.st_ino == stpwd.st_ino) {
 386                         return pwd;
 387                 }
 388                 return NULL;
 389         }
 390         return buf;
 391 }