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. 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 #include "builtins.h"
  67
  68 static int cdlogical(char *);
  69 static int cdphysical(char *);
  70 static int docd(char *, int, int);
  71 static char *getcomponent(void);
  72 static char *findcwd(char *);
  73 static void updatepwd(char *);
  74 static char *getpwd(void);
  75 static char *getpwd2(void);
  76
  77 static char *curdir = NULL;     /* current working directory */
  78 static char *prevdir;           /* previous working directory */
  79 static char *cdcomppath;
  80
  81 int
  82 cdcmd(int argc __unused, char **argv __unused)
  83 {
  84         const char *dest;
  85         const char *path;
  86         char *p;
  87         struct stat statb;
  88         int ch, phys, print = 0, getcwderr = 0;
  89         int rc;
  90         int errno1 = ENOENT;
  91
  92         phys = Pflag;
  93         while ((ch = nextopt("eLP")) != '\0') {
  94                 switch (ch) {
  95                 case 'e':
  96                         getcwderr = 1;
  97                         break;
  98                 case 'L':
  99                         phys = 0;
 100                         break;
 101                 case 'P':
 102                         phys = 1;
 103                         break;
 104                 }
 105         }
 106
 107         if (*argptr != NULL && argptr[1] != NULL)
 108                 error("too many arguments");
 109
 110         if ((dest = *argptr) == 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[0] == '/' ||
 122             (dest[0] == '.' && (dest[1] == '/' || dest[1] == '\0')) ||
 123             (dest[0] == '.' && dest[1] == '.' && (dest[2] == '/' || dest[2] == '\0')) ||
 124             (path = bltinlookup("CDPATH", 1)) == NULL)
 125                 path = "";
 126         while ((p = padvance(&path, dest)) != NULL) {
 127                 if (stat(p, &statb) < 0) {
 128                         if (errno != ENOENT)
 129                                 errno1 = errno;
 130                 } else if (!S_ISDIR(statb.st_mode))
 131                         errno1 = ENOTDIR;
 132                 else {
 133                         if (!print) {
 134                                 /*
 135                                  * XXX - rethink
 136                                  */
 137                                 if (p[0] == '.' && p[1] == '/' && p[2] != '\0')
 138                                         print = strcmp(p + 2, dest);
 139                                 else
 140                                         print = strcmp(p, dest);
 141                         }
 142                         rc = docd(p, print, phys);
 143                         if (rc >= 0)
 144                                 return getcwderr ? rc : 0;
 145                         if (errno != ENOENT)
 146                                 errno1 = errno;
 147                 }
 148         }
 149         error("%s: %s", dest, strerror(errno1));
 150         /*NOTREACHED*/
 151         return 0;
 152 }
 153
 154
 155 /*
 156  * Actually change the directory.  In an interactive shell, print the
 157  * directory name if "print" is nonzero.
 158  */
 159 static int
 160 docd(char *dest, int print, int phys)
 161 {
 162         int rc;
 163
 164         TRACE(("docd(\"%s\", %d, %d) called\n", dest, print, phys));
 165
 166         /* If logical cd fails, fall back to physical. */
 167         if ((phys || (rc = cdlogical(dest)) < 0) && (rc = cdphysical(dest)) < 0)
 168                 return (-1);
 169
 170         if (print && iflag && curdir)
 171                 out1fmt("%s\n", curdir);
 172
 173         return (rc);
 174 }
 175
 176 static int
 177 cdlogical(char *dest)
 178 {
 179         char *p;
 180         char *q;
 181         char *component;
 182         struct stat statb;
 183         int first;
 184         int badstat;
 185
 186         /*
 187          *  Check each component of the path. If we find a symlink or
 188          *  something we can't stat, clear curdir to force a getcwd()
 189          *  next time we get the value of the current directory.
 190          */
 191         badstat = 0;
 192         cdcomppath = stsavestr(dest);
 193         STARTSTACKSTR(p);
 194         if (*dest == '/') {
 195                 STPUTC('/', p);
 196                 cdcomppath++;
 197         }
 198         first = 1;
 199         while ((q = getcomponent()) != NULL) {
 200                 if (q[0] == '\0' || (q[0] == '.' && q[1] == '\0'))
 201                         continue;
 202                 if (! first)
 203                         STPUTC('/', p);
 204                 first = 0;
 205                 component = q;
 206                 STPUTS(q, p);
 207                 if (equal(component, ".."))
 208                         continue;
 209                 STACKSTRNUL(p);
 210                 if (lstat(stackblock(), &statb) < 0) {
 211                         badstat = 1;
 212                         break;
 213                 }
 214         }
 215
 216         INTOFF;
 217         if ((p = findcwd(badstat ? NULL : dest)) == NULL || chdir(p) < 0) {
 218                 INTON;
 219                 return (-1);
 220         }
 221         updatepwd(p);
 222         INTON;
 223         return (0);
 224 }
 225
 226 static int
 227 cdphysical(char *dest)
 228 {
 229         char *p;
 230         int rc = 0;
 231
 232         INTOFF;
 233         if (chdir(dest) < 0) {
 234                 INTON;
 235                 return (-1);
 236         }
 237         p = findcwd(NULL);
 238         if (p == NULL) {
 239                 warning("warning: failed to get name of current directory");
 240                 rc = 1;
 241         }
 242         updatepwd(p);
 243         INTON;
 244         return (rc);
 245 }
 246
 247 /*
 248  * Get the next component of the path name pointed to by cdcomppath.
 249  * This routine overwrites the string pointed to by cdcomppath.
 250  */
 251 static char *
 252 getcomponent(void)
 253 {
 254         char *p;
 255         char *start;
 256
 257         if ((p = cdcomppath) == NULL)
 258                 return NULL;
 259         start = cdcomppath;
 260         while (*p != '/' && *p != '\0')
 261                 p++;
 262         if (*p == '\0') {
 263                 cdcomppath = NULL;
 264         } else {
 265                 *p++ = '\0';
 266                 cdcomppath = p;
 267         }
 268         return start;
 269 }
 270
 271
 272 static char *
 273 findcwd(char *dir)
 274 {
 275         char *new;
 276         char *p;
 277
 278         /*
 279          * If our argument is NULL, we don't know the current directory
 280          * any more because we traversed a symbolic link or something
 281          * we couldn't stat().
 282          */
 283         if (dir == NULL || curdir == NULL)
 284                 return getpwd2();
 285         cdcomppath = stsavestr(dir);
 286         STARTSTACKSTR(new);
 287         if (*dir != '/') {
 288                 STPUTS(curdir, new);
 289                 if (STTOPC(new) == '/')
 290                         STUNPUTC(new);
 291         }
 292         while ((p = getcomponent()) != NULL) {
 293                 if (equal(p, "..")) {
 294                         while (new > stackblock() && (STUNPUTC(new), *new) != '/');
 295                 } else if (*p != '\0' && ! equal(p, ".")) {
 296                         STPUTC('/', new);
 297                         STPUTS(p, new);
 298                 }
 299         }
 300         if (new == stackblock())
 301                 STPUTC('/', new);
 302         STACKSTRNUL(new);
 303         return stackblock();
 304 }
 305
 306 /*
 307  * Update curdir (the name of the current directory) in response to a
 308  * cd command.  We also call hashcd to let the routines in exec.c know
 309  * that the current directory has changed.
 310  */
 311 static void
 312 updatepwd(char *dir)
 313 {
 314         hashcd();                               /* update command hash table */
 315
 316         if (prevdir)
 317                 ckfree(prevdir);
 318         prevdir = curdir;
 319         curdir = dir ? savestr(dir) : NULL;
 320         setvar("PWD", curdir, VEXPORT);
 321         setvar("OLDPWD", prevdir, VEXPORT);
 322 }
 323
 324 int
 325 pwdcmd(int argc __unused, char **argv __unused)
 326 {
 327         char *p;
 328         int ch, phys;
 329
 330         phys = Pflag;
 331         while ((ch = nextopt("LP")) != '\0') {
 332                 switch (ch) {
 333                 case 'L':
 334                         phys = 0;
 335                         break;
 336                 case 'P':
 337                         phys = 1;
 338                         break;
 339                 }
 340         }
 341
 342         if (*argptr != NULL)
 343                 error("too many arguments");
 344
 345         if (!phys && getpwd()) {
 346                 out1str(curdir);
 347                 out1c('\n');
 348         } else {
 349                 if ((p = getpwd2()) == NULL)
 350                         error(".: %s", strerror(errno));
 351                 out1str(p);
 352                 out1c('\n');
 353         }
 354
 355         return 0;
 356 }
 357
 358 /*
 359  * Get the current directory and cache the result in curdir.
 360  */
 361 static char *
 362 getpwd(void)
 363 {
 364         char *p;
 365
 366         if (curdir)
 367                 return curdir;
 368
 369         p = getpwd2();
 370         if (p != NULL)
 371                 curdir = savestr(p);
 372
 373         return curdir;
 374 }
 375
 376 #define MAXPWD 256
 377
 378 /*
 379  * Return the current directory.
 380  */
 381 static char *
 382 getpwd2(void)
 383 {
 384         char *pwd;
 385         int i;
 386
 387         for (i = MAXPWD;; i *= 2) {
 388                 pwd = stalloc(i);
 389                 if (getcwd(pwd, i) != NULL)
 390                         return pwd;
 391                 stunalloc(pwd);
 392                 if (errno != ERANGE)
 393                         break;
 394         }
 395
 396         return NULL;
 397 }
 398
 399 /*
 400  * Initialize PWD in a new shell.
 401  * If the shell is interactive, we need to warn if this fails.
 402  */
 403 void
 404 pwd_init(int warn)
 405 {
 406         char *pwd;
 407         struct stat stdot, stpwd;
 408
 409         pwd = lookupvar("PWD");
 410         if (pwd && *pwd == '/' && stat(".", &stdot) != -1 &&
 411             stat(pwd, &stpwd) != -1 &&
 412             stdot.st_dev == stpwd.st_dev &&
 413             stdot.st_ino == stpwd.st_ino) {
 414                 if (curdir)
 415                         ckfree(curdir);
 416                 curdir = savestr(pwd);
 417         }
 418         if (getpwd() == NULL && warn)
 419                 out2fmt_flush("sh: cannot determine working directory\n");
 420         setvar("PWD", curdir, VEXPORT);
 421 }