4.4BSD/usr/src/bin/sh/cd.c
/*-
* 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. 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.
*/
#ifndef lint
static char sccsid[] = "@(#)cd.c 8.1 (Berkeley) 5/31/93";
#endif /* not lint */
/*
* 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 "mystring.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <errno.h>
#ifdef __STDC__
STATIC int docd(char *, int);
STATIC void updatepwd(char *);
STATIC void getpwd(void);
STATIC char *getcomponent(void);
#else
STATIC int docd();
STATIC void updatepwd();
STATIC void getpwd();
STATIC char *getcomponent();
#endif
char *curdir; /* current working directory */
char *prevdir; /* previous working directory */
STATIC char *cdcomppath;
int
cdcmd(argc, argv) char **argv; {
char *dest;
char *path;
char *p;
struct stat statb;
char *padvance();
int print = 0;
nextopt(nullstr);
if ((dest = *argptr) == NULL && (dest = bltinlookup("HOME", 1)) == NULL)
error("HOME not set");
if (dest[0] == '-' && dest[1] == '\0') {
dest = prevdir ? prevdir : curdir;
print = 1;
}
if (*dest == '/' || (path = bltinlookup("CDPATH", 1)) == NULL)
path = nullstr;
while ((p = padvance(&path, dest)) != NULL) {
if (stat(p, &statb) >= 0
&& (statb.st_mode & S_IFMT) == S_IFDIR) {
if (!print) {
/*
* XXX - rethink
*/
if (p[0] == '.' && p[1] == '/')
p += 2;
print = strcmp(p, dest);
}
if (docd(p, print) >= 0)
return 0;
}
}
error("can't cd to %s", dest);
}
/*
* Actually do the chdir. If the name refers to symbolic links, we
* compute the actual directory name before doing the cd. In an
* interactive shell, print the directory name if "print" is nonzero
* or if the name refers to a symbolic link. We also print the name
* if "/u/logname" was expanded in it, since this is similar to a
* symbolic link. (The check for this breaks if the user gives the
* cd command some additional, unused arguments.)
*/
#if SYMLINKS == 0
STATIC int
docd(dest, print)
char *dest;
{
INTOFF;
if (chdir(dest) < 0) {
INTON;
return -1;
}
updatepwd(dest);
INTON;
if (print && iflag)
out1fmt("%s\n", stackblock());
return 0;
}
#else
STATIC int
docd(dest, print)
char *dest;
{
register char *p;
register char *q;
char *symlink;
char *component;
struct stat statb;
int first;
int i;
TRACE(("docd(\"%s\", %d) called\n", dest, print));
top:
cdcomppath = dest;
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)
error("lstat %s failed", stackblock());
if ((statb.st_mode & S_IFMT) != S_IFLNK)
continue;
/* Hit a symbolic link. We have to start all over again. */
print = 1;
STPUTC('\0', p);
symlink = grabstackstr(p);
i = (int)statb.st_size + 2; /* 2 for '/' and '\0' */
if (cdcomppath != NULL)
i += strlen(cdcomppath);
p = stalloc(i);
if (readlink(symlink, p, (int)statb.st_size) < 0) {
error("readlink %s failed", stackblock());
}
if (cdcomppath != NULL) {
p[(int)statb.st_size] = '/';
scopy(cdcomppath, p + (int)statb.st_size + 1);
} else {
p[(int)statb.st_size] = '\0';
}
if (p[0] != '/') { /* relative path name */
char *r;
q = r = symlink;
while (*q) {
if (*q++ == '/')
r = q;
}
*r = '\0';
dest = stalloc(strlen(symlink) + strlen(p) + 1);
scopy(symlink, dest);
strcat(dest, p);
} else {
dest = p;
}
goto top;
}
STPUTC('\0', p);
p = grabstackstr(p);
INTOFF;
if (chdir(p) < 0) {
INTON;
return -1;
}
updatepwd(p);
INTON;
if (print && iflag)
out1fmt("%s\n", p);
return 0;
}
#endif /* SYMLINKS */
/*
* Get the next component of the path name pointed to by cdcomppath.
* This routine overwrites the string pointed to by cdcomppath.
*/
STATIC char *
getcomponent() {
register 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.
*/
void hashcd();
STATIC void
updatepwd(dir)
char *dir;
{
char *new;
char *p;
hashcd(); /* update command hash table */
cdcomppath = stalloc(strlen(dir) + 1);
scopy(dir, cdcomppath);
STARTSTACKSTR(new);
if (*dir != '/') {
if (curdir == NULL)
return;
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());
INTON;
}
int
pwdcmd(argc, argv) char **argv; {
getpwd();
out1str(curdir);
out1c('\n');
return 0;
}
/*
* Run /bin/pwd to find out what the current directory is. We suppress
* interrupts throughout most of this, but the user can still break out
* of it by killing the pwd program. If we already know the current
* directory, this routine returns immediately.
*/
#define MAXPWD 256
STATIC void
getpwd() {
char buf[MAXPWD];
char *p;
int i;
int status;
struct job *jp;
int pip[2];
if (curdir)
return;
INTOFF;
if (pipe(pip) < 0)
error("Pipe call failed");
jp = makejob((union node *)NULL, 1);
if (forkshell(jp, (union node *)NULL, FORK_NOJOB) == 0) {
close(pip[0]);
if (pip[1] != 1) {
close(1);
copyfd(pip[1], 1);
close(pip[1]);
}
execl("/bin/pwd", "pwd", (char *)0);
error("Cannot exec /bin/pwd");
}
close(pip[1]);
pip[1] = -1;
p = buf;
while ((i = read(pip[0], p, buf + MAXPWD - p)) > 0
|| i == -1 && errno == EINTR) {
if (i > 0)
p += i;
}
close(pip[0]);
pip[0] = -1;
status = waitforjob(jp);
if (status != 0)
error((char *)0);
if (i < 0 || p == buf || p[-1] != '\n')
error("pwd command failed");
p[-1] = '\0';
curdir = savestr(buf);
INTON;
}