/* $NetBSD: cd.c,v 1.34 2003/11/14 20:00:28 dsl Exp $ */
/*-
* Copyright (c) 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Kenneth Almquist.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
#ifndef lint
#if 0
static char sccsid[] = "@(#)cd.c 8.2 (Berkeley) 5/4/95";
#else
__RCSID("$NetBSD: cd.c,v 1.34 2003/11/14 20:00:28 dsl Exp $");
#endif
#endif /* not lint */
#include <sys/types.h>
#include <sys/stat.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
/*
* The cd and pwd commands.
*/
#include "shell.h"
#include "var.h"
#include "nodes.h" /* for jobs.h */
#include "jobs.h"
#include "options.h"
#include "output.h"
#include "memalloc.h"
#include "error.h"
#include "exec.h"
#include "redir.h"
#include "mystring.h"
#include "show.h"
#include "cd.h"
STATIC int docd(char *, int);
STATIC char *getcomponent(void);
STATIC void updatepwd(char *);
STATIC void find_curdir(int noerror);
char *curdir = NULL; /* current working directory */
char *prevdir; /* previous working directory */
STATIC char *cdcomppath;
int
cdcmd(int argc, char **argv)
{
const char *dest;
const char *path;
char *p, *d;
struct stat statb;
int print = cdprint; /* set -cdprint to enable */
nextopt(nullstr);
/*
* Try (quite hard) to have 'curdir' defined, nothing has set
* it on entry to the shell, but we want 'cd fred; cd -' to work.
*/
getpwd(1);
dest = *argptr;
if (dest == NULL) {
dest = bltinlookup("HOME", 1);
if (dest == NULL)
error("HOME not set");
} else {
if (argptr[1]) {
/* Do 'ksh' style substitution */
if (!curdir)
error("PWD not set");
p = strstr(curdir, dest);
if (!p)
error("bad substitution");
d = stalloc(strlen(curdir) + strlen(argptr[1]) + 1);
memcpy(d, curdir, p - curdir);
strcpy(d + (p - curdir), argptr[1]);
strcat(d, p + strlen(dest));
dest = d;
print = 1;
}
}
if (dest[0] == '-' && dest[1] == '\0') {
dest = prevdir ? prevdir : curdir;
print = 1;
}
if (*dest == '\0')
dest = ".";
if (*dest == '/' || (path = bltinlookup("CDPATH", 1)) == NULL)
path = nullstr;
while ((p = padvance(&path, dest)) != NULL) {
if (stat(p, &statb) >= 0 && S_ISDIR(statb.st_mode)) {
if (!print) {
/*
* XXX - rethink
*/
if (p[0] == '.' && p[1] == '/' && p[2] != '\0')
p += 2;
print = strcmp(p, dest);
}
if (docd(p, print) >= 0)
return 0;
}
}
error("can't cd to %s", dest);
/* NOTREACHED */
}
/*
* Actually do the chdir. In an interactive shell, print the
* directory name if "print" is nonzero.
*/
STATIC int
docd(char *dest, int print)
{
char *p;
char *q;
char *component;
struct stat statb;
int first;
int badstat;
TRACE(("docd(\"%s\", %d) called\n", dest, print));
/*
* Check each component of the path. If we find a symlink or
* something we can't stat, clear curdir to force a getcwd()
* next time we get the value of the current directory.
*/
badstat = 0;
cdcomppath = stalloc(strlen(dest) + 1);
scopy(dest, cdcomppath);
STARTSTACKSTR(p);
if (*dest == '/') {
STPUTC('/', p);
cdcomppath++;
}
first = 1;
while ((q = getcomponent()) != NULL) {
if (q[0] == '\0' || (q[0] == '.' && q[1] == '\0'))
continue;
if (! first)
STPUTC('/', p);
first = 0;
component = q;
while (*q)
STPUTC(*q++, p);
if (equal(component, ".."))
continue;
STACKSTRNUL(p);
if ((lstat(stackblock(), &statb) < 0)
|| (S_ISLNK(statb.st_mode))) {
/* print = 1; */
badstat = 1;
break;
}
}
INTOFF;
if (chdir(dest) < 0) {
INTON;
return -1;
}
updatepwd(badstat ? NULL : dest);
INTON;
if (print && iflag && curdir)
out1fmt("%s\n", curdir);
return 0;
}
/*
* Get the next component of the path name pointed to by cdcomppath.
* This routine overwrites the string pointed to by cdcomppath.
*/
STATIC char *
getcomponent()
{
char *p;
char *start;
if ((p = cdcomppath) == NULL)
return NULL;
start = cdcomppath;
while (*p != '/' && *p != '\0')
p++;
if (*p == '\0') {
cdcomppath = NULL;
} else {
*p++ = '\0';
cdcomppath = p;
}
return start;
}
/*
* Update curdir (the name of the current directory) in response to a
* cd command. We also call hashcd to let the routines in exec.c know
* that the current directory has changed.
*/
STATIC void
updatepwd(char *dir)
{
char *new;
char *p;
hashcd(); /* update command hash table */
/*
* If our argument is NULL, we don't know the current directory
* any more because we traversed a symbolic link or something
* we couldn't stat().
*/
if (dir == NULL || curdir == NULL) {
if (prevdir)
ckfree(prevdir);
INTOFF;
prevdir = curdir;
curdir = NULL;
getpwd(1);
INTON;
if (curdir)
setvar("PWD", curdir, VEXPORT);
else
unsetvar("PWD", 0);
return;
}
cdcomppath = stalloc(strlen(dir) + 1);
scopy(dir, cdcomppath);
STARTSTACKSTR(new);
if (*dir != '/') {
p = curdir;
while (*p)
STPUTC(*p++, new);
if (p[-1] == '/')
STUNPUTC(new);
}
while ((p = getcomponent()) != NULL) {
if (equal(p, "..")) {
while (new > stackblock() && (STUNPUTC(new), *new) != '/');
} else if (*p != '\0' && ! equal(p, ".")) {
STPUTC('/', new);
while (*p)
STPUTC(*p++, new);
}
}
if (new == stackblock())
STPUTC('/', new);
STACKSTRNUL(new);
INTOFF;
if (prevdir)
ckfree(prevdir);
prevdir = curdir;
curdir = savestr(stackblock());
setvar("PWD", curdir, VEXPORT);
INTON;
}
/*
* Posix says the default should be 'pwd -L' (as below), however
* the 'cd' command (above) does something much nearer to the
* posix 'cd -P' (not the posix default of 'cd -L').
* If 'cd' is changed to support -P/L then the default here
* needs to be revisited if the historic behaviour is to be kept.
*/
int
pwdcmd(int argc, char **argv)
{
int i;
char opt = 'L';
while ((i = nextopt("LP")) != '\0')
opt = i;
if (*argptr)
error("unexpected argument");
if (opt == 'L')
getpwd(0);
else
find_curdir(0);
setvar("PWD", curdir, VEXPORT);
out1str(curdir);
out1c('\n');
return 0;
}
#define MAXPWD 256
/*
* Find out what the current directory is. If we already know the current
* directory, this routine returns immediately.
*/
void
getpwd(int noerror)
{
char *pwd;
struct stat stdot, stpwd;
static int first = 1;
if (curdir)
return;
if (first) {
first = 0;
pwd = getenv("PWD");
if (pwd && *pwd == '/' && stat(".", &stdot) != -1 &&
stat(pwd, &stpwd) != -1 &&
stdot.st_dev == stpwd.st_dev &&
stdot.st_ino == stpwd.st_ino) {
curdir = savestr(pwd);
return;
}
}
find_curdir(noerror);
return;
}
STATIC void
find_curdir(int noerror)
{
int i;
char *pwd;
/*
* Things are a bit complicated here; we could have just used
* getcwd, but traditionally getcwd is implemented using popen
* to /bin/pwd. This creates a problem for us, since we cannot
* keep track of the job if it is being ran behind our backs.
* So we re-implement getcwd(), and we suppress interrupts
* throughout the process. This is not completely safe, since
* the user can still break out of it by killing the pwd program.
* We still try to use getcwd for systems that we know have a
* c implementation of getcwd, that does not open a pipe to
* /bin/pwd.
*/
#if defined(__NetBSD__) || defined(__SVR4) || defined(__linux__)
for (i = MAXPWD;; i *= 2) {
pwd = stalloc(i);
if (getcwd(pwd, i) != NULL) {
curdir = savestr(pwd);
return;
}
stunalloc(pwd);
if (errno == ERANGE)
continue;
if (!noerror)
error("getcwd() failed: %s", strerror(errno));
return;
}
#else
{
char *p;
int status;
struct job *jp;
int pip[2];
pwd = stalloc(MAXPWD);
INTOFF;
if (pipe(pip) < 0)
error("Pipe call failed");
jp = makejob((union node *)NULL, 1);
if (forkshell(jp, (union node *)NULL, FORK_NOJOB) == 0) {
(void) close(pip[0]);
if (pip[1] != 1) {
close(1);
copyfd(pip[1], 1);
close(pip[1]);
}
(void) execl("/bin/pwd", "pwd", (char *)0);
sh_warn("Cannot exec /bin/pwd");
exit(1);
}
(void) close(pip[1]);
pip[1] = -1;
p = pwd;
while ((i = read(pip[0], p, pwd + MAXPWD - p)) > 0
|| (i == -1 && errno == EINTR)) {
if (i > 0)
p += i;
}
(void) close(pip[0]);
pip[0] = -1;
status = waitforjob(jp);
if (status != 0)
error((char *)0);
if (i < 0 || p == pwd || p[-1] != '\n') {
if (noerror) {
INTON;
return;
}
error("pwd command failed");
}
p[-1] = '\0';
INTON;
curdir = savestr(pwd);
return;
}
#endif
}