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/* $NetBSD: cd.c,v 1.34 2003/11/14 20:00:28 dsl Exp $ */
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* Copyright (c) 1991, 1993
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* The Regents of the University of California. All rights reserved.
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* This code is derived from software contributed to Berkeley by
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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#include <sys/cdefs.h>
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static char sccsid[] = "@(#)cd.c 8.2 (Berkeley) 5/4/95";
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__RCSID("$NetBSD: cd.c,v 1.34 2003/11/14 20:00:28 dsl Exp $");
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#include <sys/types.h>
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* The cd and pwd commands.
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#include "nodes.h" /* for jobs.h */
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STATIC int docd(char *, int);
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STATIC char *getcomponent(void);
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STATIC void updatepwd(char *);
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STATIC void find_curdir(int noerror);
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char *curdir = NULL; /* current working directory */
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char *prevdir; /* previous working directory */
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STATIC char *cdcomppath;
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cdcmd(int argc, char **argv)
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int print = cdprint; /* set -cdprint to enable */
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(void)argc; (void)argv;
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* Try (quite hard) to have 'curdir' defined, nothing has set
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* it on entry to the shell, but we want 'cd fred; cd -' to work.
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dest = bltinlookup("HOME", 1);
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error("HOME not set");
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/* Do 'ksh' style substitution */
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error("PWD not set");
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p = strstr(curdir, dest);
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error("bad substitution");
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d = stalloc(strlen(curdir) + strlen(argptr[1]) + 1);
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memcpy(d, curdir, p - curdir);
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strcpy(d + (p - curdir), argptr[1]);
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strcat(d, p + strlen(dest));
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if (dest[0] == '-' && dest[1] == '\0') {
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dest = prevdir ? prevdir : curdir;
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if (*dest == '/' || (path = bltinlookup("CDPATH", 1)) == NULL)
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while ((p = padvance(&path, dest)) != NULL) {
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if (stat(p, &statb) >= 0 && S_ISDIR(statb.st_mode)) {
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if (p[0] == '.' && p[1] == '/' && p[2] != '\0')
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print = strcmp(p, dest);
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if (docd(p, print) >= 0)
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error("can't cd to %s", dest);
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* Actually do the chdir. In an interactive shell, print the
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* directory name if "print" is nonzero.
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docd(char *dest, int print)
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TRACE(("docd(\"%s\", %d) called\n", dest, print));
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* Check each component of the path. If we find a symlink or
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* something we can't stat, clear curdir to force a getcwd()
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* next time we get the value of the current directory.
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cdcomppath = stalloc(strlen(dest) + 1);
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scopy(dest, cdcomppath);
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while ((q = getcomponent()) != NULL) {
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if (q[0] == '\0' || (q[0] == '.' && q[1] == '\0'))
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if (equal(component, ".."))
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if ((lstat(stackblock(), &statb) < 0)
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|| (S_ISLNK(statb.st_mode))) {
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if (chdir(dest) < 0) {
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updatepwd(badstat ? NULL : dest);
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if (print && iflag && curdir)
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out1fmt("%s\n", curdir);
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* Get the next component of the path name pointed to by cdcomppath.
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* This routine overwrites the string pointed to by cdcomppath.
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if ((p = cdcomppath) == NULL)
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while (*p != '/' && *p != '\0')
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* Update curdir (the name of the current directory) in response to a
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* cd command. We also call hashcd to let the routines in exec.c know
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* that the current directory has changed.
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hashcd(); /* update command hash table */
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* If our argument is NULL, we don't know the current directory
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* any more because we traversed a symbolic link or something
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* we couldn't stat().
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if (dir == NULL || curdir == NULL) {
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setvar("PWD", curdir, VEXPORT);
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cdcomppath = stalloc(strlen(dir) + 1);
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scopy(dir, cdcomppath);
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while ((p = getcomponent()) != NULL) {
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if (equal(p, "..")) {
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while (new > stackblock() && (STUNPUTC(new), *new) != '/');
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} else if (*p != '\0' && ! equal(p, ".")) {
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if (new == stackblock())
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curdir = savestr(stackblock());
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setvar("PWD", curdir, VEXPORT);
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* Posix says the default should be 'pwd -L' (as below), however
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* the 'cd' command (above) does something much nearer to the
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* posix 'cd -P' (not the posix default of 'cd -L').
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* If 'cd' is changed to support -P/L then the default here
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* needs to be revisited if the historic behaviour is to be kept.
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pwdcmd(int argc, char **argv)
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(void)argc; (void)argv;
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while ((i = nextopt("LP")) != '\0')
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error("unexpected argument");
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setvar("PWD", curdir, VEXPORT);
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#define MAXPWD PATH_MAX
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* Find out what the current directory is. If we already know the current
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* directory, this routine returns immediately.
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struct stat stdot, stpwd;
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static int first = 1;
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if (pwd && *pwd == '/' && stat(".", &stdot) != -1 &&
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stat(pwd, &stpwd) != -1 &&
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stdot.st_dev == stpwd.st_dev &&
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stdot.st_ino == stpwd.st_ino) {
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curdir = savestr(pwd);
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find_curdir(noerror);
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find_curdir(int noerror)
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* Things are a bit complicated here; we could have just used
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* getcwd, but traditionally getcwd is implemented using popen
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* to /bin/pwd. This creates a problem for us, since we cannot
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* keep track of the job if it is being ran behind our backs.
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* So we re-implement getcwd(), and we suppress interrupts
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* throughout the process. This is not completely safe, since
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* the user can still break out of it by killing the pwd program.
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* We still try to use getcwd for systems that we know have a
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* c implementation of getcwd, that does not open a pipe to
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#if defined(__NetBSD__) || defined(__SVR4) || defined(__linux__)
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for (i = MAXPWD;; i *= 2) {
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if (getcwd(pwd, i) != NULL) {
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curdir = savestr(pwd);
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error("getcwd() failed: %s", strerror(errno));
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pwd = stalloc(MAXPWD);
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error("Pipe call failed");
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jp = makejob((union node *)NULL, 1);
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if (forkshell(jp, (union node *)NULL, FORK_NOJOB) == 0) {
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(void) close(pip[0]);
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(void) execl("/bin/pwd", "pwd", (char *)0);
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error("Cannot exec /bin/pwd");
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(void) close(pip[1]);
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while ((i = read(pip[0], p, pwd + MAXPWD - p)) > 0
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|| (i == -1 && errno == EINTR)) {
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(void) close(pip[0]);
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status = waitforjob(jp);
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if (i < 0 || p == pwd || p[-1] != '\n') {
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error("pwd command failed");
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curdir = savestr(pwd);
added
removed
ash/cd.c
