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  * 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  * @(#)cd.c     8.2 (Berkeley) 5/4/95
  37  * $FreeBSD: src/bin/sh/cd.c,v 1.35 2006/06/12 21:06:00 stefanf Exp $
  38  * $DragonFly: src/bin/sh/cd.c,v 1.5 2007/01/05 22:18:52 pavalos Exp $
  39  */
  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 int updatepwd(char *);
  72
  73 STATIC char *curdir = NULL;     /* current working directory */
  74 STATIC char *prevdir;           /* previous working directory */
  75 STATIC char *cdcomppath;
  76
  77 int
  78 cdcmd(int argc, char **argv)
  79 {
  80         const char *dest;
  81         const char *path;
  82         char *p;
  83         struct stat statb;
  84         int ch, phys, print = 0;
  85
  86         optreset = 1; optind = 1; opterr = 0; /* initialize getopt */
  87         phys = Pflag;
  88         while ((ch = getopt(argc, argv, "LP")) != -1) {
  89                 switch (ch) {
  90                 case 'L':
  91                         phys = 0;
  92                         break;
  93                 case 'P':
  94                         phys = 1;
  95                         break;
  96                 default:
  97                         error("unknown option: -%c", optopt);
  98                         break;
  99                 }
 100         }
 101         argc -= optind;
 102         argv += optind;
 103
 104         if (argc > 1)
 105                 error("too many arguments");
 106
 107         if ((dest = *argv) == NULL && (dest = bltinlookup("HOME", 1)) == NULL)
 108                 error("HOME not set");
 109         if (*dest == '\0')
 110                 dest = ".";
 111         if (dest[0] == '-' && dest[1] == '\0') {
 112                 dest = prevdir ? prevdir : curdir;
 113                 if (dest)
 114                         print = 1;
 115                 else
 116                         dest = ".";
 117         }
 118         if (*dest == '/' || (path = bltinlookup("CDPATH", 1)) == NULL)
 119                 path = nullstr;
 120         while ((p = padvance(&path, dest)) != NULL) {
 121                 if (stat(p, &statb) >= 0 && S_ISDIR(statb.st_mode)) {
 122                         if (!print) {
 123                                 /*
 124                                  * XXX - rethink
 125                                  */
 126                                 if (p[0] == '.' && p[1] == '/' && p[2] != '\0')
 127                                         print = strcmp(p + 2, dest);
 128                                 else
 129                                         print = strcmp(p, dest);
 130                         }
 131                         if (docd(p, print, phys) >= 0)
 132                                 return 0;
 133                 }
 134         }
 135         error("can't cd to %s", dest);
 136         /*NOTREACHED*/
 137         return 0;
 138 }
 139
 140
 141 /*
 142  * Actually change the directory.  In an interactive shell, print the
 143  * directory name if "print" is nonzero.
 144  */
 145 STATIC int
 146 docd(char *dest, int print, int phys)
 147 {
 148
 149         TRACE(("docd(\"%s\", %d, %d) called\n", dest, print, phys));
 150
 151         /* If logical cd fails, fall back to physical. */
 152         if ((phys || cdlogical(dest) < 0) && cdphysical(dest) < 0)
 153                 return (-1);
 154
 155         if (print && iflag && curdir)
 156                 out1fmt("%s\n", curdir);
 157
 158         return 0;
 159 }
 160
 161 STATIC int
 162 cdlogical(char *dest)
 163 {
 164         char *p;
 165         char *q;
 166         char *component;
 167         struct stat statb;
 168         int first;
 169         int badstat;
 170
 171         /*
 172          *  Check each component of the path. If we find a symlink or
 173          *  something we can't stat, clear curdir to force a getcwd()
 174          *  next time we get the value of the current directory.
 175          */
 176         badstat = 0;
 177         cdcomppath = stalloc(strlen(dest) + 1);
 178         scopy(dest, cdcomppath);
 179         STARTSTACKSTR(p);
 180         if (*dest == '/') {
 181                 STPUTC('/', p);
 182                 cdcomppath++;
 183         }
 184         first = 1;
 185         while ((q = getcomponent()) != NULL) {
 186                 if (q[0] == '\0' || (q[0] == '.' && q[1] == '\0'))
 187                         continue;
 188                 if (! first)
 189                         STPUTC('/', p);
 190                 first = 0;
 191                 component = q;
 192                 while (*q)
 193                         STPUTC(*q++, p);
 194                 if (equal(component, ".."))
 195                         continue;
 196                 STACKSTRNUL(p);
 197                 if (lstat(stackblock(), &statb) < 0) {
 198                         badstat = 1;
 199                         break;
 200                 }
 201         }
 202
 203         INTOFF;
 204         if (updatepwd(badstat ? NULL : dest) < 0 || chdir(curdir) < 0) {
 205                 INTON;
 206                 return (-1);
 207         }
 208         INTON;
 209         return (0);
 210 }
 211
 212 STATIC int
 213 cdphysical(char *dest)
 214 {
 215
 216         INTOFF;
 217         if (chdir(dest) < 0 || updatepwd(NULL) < 0) {
 218                 INTON;
 219                 return (-1);
 220         }
 221         INTON;
 222         return (0);
 223 }
 224
 225 /*
 226  * Get the next component of the path name pointed to by cdcomppath.
 227  * This routine overwrites the string pointed to by cdcomppath.
 228  */
 229 STATIC char *
 230 getcomponent(void)
 231 {
 232         char *p;
 233         char *start;
 234
 235         if ((p = cdcomppath) == NULL)
 236                 return NULL;
 237         start = cdcomppath;
 238         while (*p != '/' && *p != '\0')
 239                 p++;
 240         if (*p == '\0') {
 241                 cdcomppath = NULL;
 242         } else {
 243                 *p++ = '\0';
 244                 cdcomppath = p;
 245         }
 246         return start;
 247 }
 248
 249
 250 /*
 251  * Update curdir (the name of the current directory) in response to a
 252  * cd command.  We also call hashcd to let the routines in exec.c know
 253  * that the current directory has changed.
 254  */
 255 STATIC int
 256 updatepwd(char *dir)
 257 {
 258         char *new;
 259         char *p;
 260
 261         hashcd();                               /* update command hash table */
 262
 263         /*
 264          * If our argument is NULL, we don't know the current directory
 265          * any more because we traversed a symbolic link or something
 266          * we couldn't stat().
 267          */
 268         if (dir == NULL || curdir == NULL)  {
 269                 if (prevdir)
 270                         ckfree(prevdir);
 271                 INTOFF;
 272                 prevdir = curdir;
 273                 curdir = NULL;
 274                 if (getpwd() == NULL) {
 275                         INTON;
 276                         return (-1);
 277                 }
 278                 setvar("PWD", curdir, VEXPORT);
 279                 setvar("OLDPWD", prevdir, VEXPORT);
 280                 INTON;
 281                 return (0);
 282         }
 283         cdcomppath = stalloc(strlen(dir) + 1);
 284         scopy(dir, cdcomppath);
 285         STARTSTACKSTR(new);
 286         if (*dir != '/') {
 287                 p = curdir;
 288                 while (*p)
 289                         STPUTC(*p++, new);
 290                 if (p[-1] == '/')
 291                         STUNPUTC(new);
 292         }
 293         while ((p = getcomponent()) != NULL) {
 294                 if (equal(p, "..")) {
 295                         while (new > stackblock() && (STUNPUTC(new), *new) != '/');
 296                 } else if (*p != '\0' && ! equal(p, ".")) {
 297                         STPUTC('/', new);
 298                         while (*p)
 299                                 STPUTC(*p++, new);
 300                 }
 301         }
 302         if (new == stackblock())
 303                 STPUTC('/', new);
 304         STACKSTRNUL(new);
 305         INTOFF;
 306         if (prevdir)
 307                 ckfree(prevdir);
 308         prevdir = curdir;
 309         curdir = savestr(stackblock());
 310         setvar("PWD", curdir, VEXPORT);
 311         setvar("OLDPWD", prevdir, VEXPORT);
 312         INTON;
 313
 314         return (0);
 315 }
 316
 317 int
 318 pwdcmd(int argc, char **argv)
 319 {
 320         char buf[PATH_MAX];
 321         int ch, phys;
 322
 323         optreset = 1; optind = 1; opterr = 0; /* initialize getopt */
 324         phys = Pflag;
 325         while ((ch = getopt(argc, argv, "LP")) != -1) {
 326                 switch (ch) {
 327                 case 'L':
 328                         phys = 0;
 329                         break;
 330                 case 'P':
 331                         phys = 1;
 332                         break;
 333                 default:
 334                         error("unknown option: -%c", optopt);
 335                         break;
 336                 }
 337         }
 338         argc -= optind;
 339         argv += optind;
 340
 341         if (argc != 0)
 342                 error("too many arguments");
 343
 344         if (!phys && getpwd()) {
 345                 out1str(curdir);
 346                 out1c('\n');
 347         } else {
 348                 if (getcwd(buf, sizeof(buf)) == NULL)
 349                         error(".: %s", strerror(errno));
 350                 out1str(buf);
 351                 out1c('\n');
 352         }
 353
 354         return 0;
 355 }
 356
 357 /*
 358  * Find out what the current directory is. If we already know the current
 359  * directory, this routine returns immediately.
 360  */
 361 char *
 362 getpwd(void)
 363 {
 364         char buf[PATH_MAX];
 365
 366         if (curdir)
 367                 return curdir;
 368         if (getcwd(buf, sizeof(buf)) == NULL) {
 369                 char *pwd = getenv("PWD");
 370                 struct stat stdot, stpwd;
 371
 372                 if (pwd && *pwd == '/' && stat(".", &stdot) != -1 &&
 373                     stat(pwd, &stpwd) != -1 &&
 374                     stdot.st_dev == stpwd.st_dev &&
 375                     stdot.st_ino == stpwd.st_ino) {
 376                         curdir = savestr(pwd);
 377                         return curdir;
 378                 }
 379                 return NULL;
 380         }
 381         curdir = savestr(buf);
 382
 383         return curdir;
 384 }