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: head/bin/sh/cd.c 356251 2020-01-01 12:06:37Z jilles $");
  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(char **);
  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
  79 int
  80 cdcmd(int argc __unused, char **argv __unused)
  81 {
  82         const char *dest;
  83         const char *path;
  84         char *p;
  85         struct stat statb;
  86         int ch, phys, print = 0, getcwderr = 0;
  87         int rc;
  88         int errno1 = ENOENT;
  89
  90         phys = Pflag;
  91         while ((ch = nextopt("eLP")) != '\0') {
  92                 switch (ch) {
  93                 case 'e':
  94                         getcwderr = 1;
  95                         break;
  96                 case 'L':
  97                         phys = 0;
  98                         break;
  99                 case 'P':
 100                         phys = 1;
 101                         break;
 102                 }
 103         }
 104
 105         if (*argptr != NULL && argptr[1] != NULL)
 106                 error("too many arguments");
 107
 108         if ((dest = *argptr) == NULL && (dest = bltinlookup("HOME", 1)) == NULL)
 109                 error("HOME not set");
 110         if (*dest == '\0')
 111                 dest = ".";
 112         if (dest[0] == '-' && dest[1] == '\0') {
 113                 dest = bltinlookup("OLDPWD", 1);
 114                 if (dest == NULL)
 115                         error("OLDPWD not set");
 116                 print = 1;
 117         }
 118         if (dest[0] == '/' ||
 119             (dest[0] == '.' && (dest[1] == '/' || dest[1] == '\0')) ||
 120             (dest[0] == '.' && dest[1] == '.' && (dest[2] == '/' || dest[2] == '\0')) ||
 121             (path = bltinlookup("CDPATH", 1)) == NULL)
 122                 path = "";
 123         while ((p = padvance(&path, NULL, dest)) != NULL) {
 124                 if (stat(p, &statb) < 0) {
 125                         if (errno != ENOENT)
 126                                 errno1 = errno;
 127                 } else if (!S_ISDIR(statb.st_mode))
 128                         errno1 = ENOTDIR;
 129                 else {
 130                         if (!print) {
 131                                 /*
 132                                  * XXX - rethink
 133                                  */
 134                                 if (p[0] == '.' && p[1] == '/' && p[2] != '\0')
 135                                         print = strcmp(p + 2, dest);
 136                                 else
 137                                         print = strcmp(p, dest);
 138                         }
 139                         rc = docd(p, print, phys);
 140                         if (rc >= 0)
 141                                 return getcwderr ? rc : 0;
 142                         if (errno != ENOENT)
 143                                 errno1 = errno;
 144                 }
 145         }
 146         error("%s: %s", dest, strerror(errno1));
 147         /*NOTREACHED*/
 148         return 0;
 149 }
 150
 151
 152 /*
 153  * Actually change the directory.  In an interactive shell, print the
 154  * directory name if "print" is nonzero.
 155  */
 156 static int
 157 docd(char *dest, int print, int phys)
 158 {
 159         int rc;
 160
 161         TRACE(("docd(\"%s\", %d, %d) called\n", dest, print, phys));
 162
 163         /* If logical cd fails, fall back to physical. */
 164         if ((phys || (rc = cdlogical(dest)) < 0) && (rc = cdphysical(dest)) < 0)
 165                 return (-1);
 166
 167         if (print && iflag && curdir) {
 168                 out1fmt("%s\n", curdir);
 169                 /*
 170                  * Ignore write errors to preserve the invariant that the
 171                  * current directory is changed iff the exit status is 0
 172                  * (or 1 if -e was given and the full pathname could not be
 173                  * determined).
 174                  */
 175                 flushout(out1);
 176                 outclearerror(out1);
 177         }
 178
 179         return (rc);
 180 }
 181
 182 static int
 183 cdlogical(char *dest)
 184 {
 185         char *p;
 186         char *q;
 187         char *component;
 188         char *path;
 189         struct stat statb;
 190         int first;
 191         int badstat;
 192
 193         /*
 194          *  Check each component of the path. If we find a symlink or
 195          *  something we can't stat, clear curdir to force a getcwd()
 196          *  next time we get the value of the current directory.
 197          */
 198         badstat = 0;
 199         path = stsavestr(dest);
 200         STARTSTACKSTR(p);
 201         if (*dest == '/') {
 202                 STPUTC('/', p);
 203                 path++;
 204         }
 205         first = 1;
 206         while ((q = getcomponent(&path)) != NULL) {
 207                 if (q[0] == '\0' || (q[0] == '.' && q[1] == '\0'))
 208                         continue;
 209                 if (! first)
 210                         STPUTC('/', p);
 211                 first = 0;
 212                 component = q;
 213                 STPUTS(q, p);
 214                 if (equal(component, ".."))
 215                         continue;
 216                 STACKSTRNUL(p);
 217                 if (lstat(stackblock(), &statb) < 0) {
 218                         badstat = 1;
 219                         break;
 220                 }
 221         }
 222
 223         INTOFF;
 224         if ((p = findcwd(badstat ? NULL : dest)) == NULL || chdir(p) < 0) {
 225                 INTON;
 226                 return (-1);
 227         }
 228         updatepwd(p);
 229         INTON;
 230         return (0);
 231 }
 232
 233 static int
 234 cdphysical(char *dest)
 235 {
 236         char *p;
 237         int rc = 0;
 238
 239         INTOFF;
 240         if (chdir(dest) < 0) {
 241                 INTON;
 242                 return (-1);
 243         }
 244         p = findcwd(NULL);
 245         if (p == NULL) {
 246                 warning("warning: failed to get name of current directory");
 247                 rc = 1;
 248         }
 249         updatepwd(p);
 250         INTON;
 251         return (rc);
 252 }
 253
 254 /*
 255  * Get the next component of the path name pointed to by *path.
 256  * This routine overwrites *path and the string pointed to by it.
 257  */
 258 static char *
 259 getcomponent(char **path)
 260 {
 261         char *p;
 262         char *start;
 263
 264         if ((p = *path) == NULL)
 265                 return NULL;
 266         start = *path;
 267         while (*p != '/' && *p != '\0')
 268                 p++;
 269         if (*p == '\0') {
 270                 *path = NULL;
 271         } else {
 272                 *p++ = '\0';
 273                 *path = p;
 274         }
 275         return start;
 276 }
 277
 278
 279 static char *
 280 findcwd(char *dir)
 281 {
 282         char *new;
 283         char *p;
 284         char *path;
 285
 286         /*
 287          * If our argument is NULL, we don't know the current directory
 288          * any more because we traversed a symbolic link or something
 289          * we couldn't stat().
 290          */
 291         if (dir == NULL || curdir == NULL)
 292                 return getpwd2();
 293         path = stsavestr(dir);
 294         STARTSTACKSTR(new);
 295         if (*dir != '/') {
 296                 STPUTS(curdir, new);
 297                 if (STTOPC(new) == '/')
 298                         STUNPUTC(new);
 299         }
 300         while ((p = getcomponent(&path)) != NULL) {
 301                 if (equal(p, "..")) {
 302                         while (new > stackblock() && (STUNPUTC(new), *new) != '/');
 303                 } else if (*p != '\0' && ! equal(p, ".")) {
 304                         STPUTC('/', new);
 305                         STPUTS(p, new);
 306                 }
 307         }
 308         if (new == stackblock())
 309                 STPUTC('/', new);
 310         STACKSTRNUL(new);
 311         return stackblock();
 312 }
 313
 314 /*
 315  * Update curdir (the name of the current directory) in response to a
 316  * cd command.  We also call hashcd to let the routines in exec.c know
 317  * that the current directory has changed.
 318  */
 319 static void
 320 updatepwd(char *dir)
 321 {
 322         char *prevdir;
 323
 324         hashcd();                               /* update command hash table */
 325
 326         setvar("PWD", dir, VEXPORT);
 327         setvar("OLDPWD", curdir, VEXPORT);
 328         prevdir = curdir;
 329         curdir = dir ? savestr(dir) : NULL;
 330         ckfree(prevdir);
 331 }
 332
 333 int
 334 pwdcmd(int argc __unused, char **argv __unused)
 335 {
 336         char *p;
 337         int ch, phys;
 338
 339         phys = Pflag;
 340         while ((ch = nextopt("LP")) != '\0') {
 341                 switch (ch) {
 342                 case 'L':
 343                         phys = 0;
 344                         break;
 345                 case 'P':
 346                         phys = 1;
 347                         break;
 348                 }
 349         }
 350
 351         if (*argptr != NULL)
 352                 error("too many arguments");
 353
 354         if (!phys && getpwd()) {
 355                 out1str(curdir);
 356                 out1c('\n');
 357         } else {
 358                 if ((p = getpwd2()) == NULL)
 359                         error(".: %s", strerror(errno));
 360                 out1str(p);
 361                 out1c('\n');
 362         }
 363
 364         return 0;
 365 }
 366
 367 /*
 368  * Get the current directory and cache the result in curdir.
 369  */
 370 static char *
 371 getpwd(void)
 372 {
 373         char *p;
 374
 375         if (curdir)
 376                 return curdir;
 377
 378         p = getpwd2();
 379         if (p != NULL) {
 380                 INTOFF;
 381                 curdir = savestr(p);
 382                 INTON;
 383         }
 384
 385         return curdir;
 386 }
 387
 388 #define MAXPWD 256
 389
 390 /*
 391  * Return the current directory.
 392  */
 393 static char *
 394 getpwd2(void)
 395 {
 396         char *pwd;
 397         int i;
 398
 399         for (i = MAXPWD;; i *= 2) {
 400                 pwd = stalloc(i);
 401                 if (getcwd(pwd, i) != NULL)
 402                         return pwd;
 403                 stunalloc(pwd);
 404                 if (errno != ERANGE)
 405                         break;
 406         }
 407
 408         return NULL;
 409 }
 410
 411 /*
 412  * Initialize PWD in a new shell.
 413  * If the shell is interactive, we need to warn if this fails.
 414  */
 415 void
 416 pwd_init(int warn)
 417 {
 418         char *pwd;
 419         struct stat stdot, stpwd;
 420
 421         pwd = lookupvar("PWD");
 422         if (pwd && *pwd == '/' && stat(".", &stdot) != -1 &&
 423             stat(pwd, &stpwd) != -1 &&
 424             stdot.st_dev == stpwd.st_dev &&
 425             stdot.st_ino == stpwd.st_ino) {
 426                 if (curdir)
 427                         ckfree(curdir);
 428                 curdir = savestr(pwd);
 429         }
 430         if (getpwd() == NULL && warn)
 431                 out2fmt_flush("sh: cannot determine working directory\n");
 432         setvar("PWD", curdir, VEXPORT);
 433 }