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Diffstat (limited to 'sh/cd.c')
| -rw-r--r-- | sh/cd.c | 446 |
1 files changed, 446 insertions, 0 deletions
@@ -0,0 +1,446 @@ +/* $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 +} |