/* $NetBSD: cd.c,v 1.50.8.1 2021/11/06 13:42:18 martin 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 #ifndef lint #if 0 static char sccsid[] = "@(#)cd.c 8.2 (Berkeley) 5/4/95"; #else __RCSID("$NetBSD: cd.c,v 1.50.8.1 2021/11/06 13:42:18 martin Exp $"); #endif #endif /* not lint */ #include #include #include #include #include #include #include /* * The cd and pwd commands. */ #include "shell.h" #include "var.h" #include "nodes.h" /* for jobs.h */ #include "jobs.h" #include "options.h" #include "builtins.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(const char *, bool, bool); STATIC char *getcomponent(void); STATIC bool updatepwd(const char *); STATIC void find_curdir(int noerror); STATIC bool is_curdir(const char *); 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, *cp; char *p; char *d; struct stat statb; char opt; bool eopt = false; int print = cdprint; /* set -o cdprint to enable */ while ((opt = nextopt("Pe")) != '\0') if (opt == 'e') eopt = true; /* * 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; } else if (dest[0] == '-' && dest[1] == '\0') { dest = prevdir ? prevdir : curdir; print = 1; } if (*dest == '\0') dest = "."; cp = dest; if (*cp == '.' && *++cp == '.') cp++; if (*cp == 0 || *cp == '/' || (path = bltinlookup("CDPATH", 1)) == NULL) path = nullstr; while ((p = padvance(&path, dest, 0)) != NULL) { stunalloc(p); if (stat(p, &statb) >= 0 && S_ISDIR(statb.st_mode)) { int dopr = print; int x; if (!print) dopr = strcmp(p, dest); if ((x = docd(p, dopr != 0, eopt)) >= 0) return x; } } 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(const char *dest, bool print, bool eopt) { bool gotpwd; #if 0 /* no "cd -L" (ever) so all this is just a waste of time ... */ char *p; char *q; char *component; struct stat statb; int first; int badstat; /* * 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) { badstat = 1; break; } } #endif CTRACE(DBG_CMDS, ("docd(\"%s\", %s, %s) called\n", dest, print ? "true" : "false", eopt ? "true" : "false")); INTOFF; if (chdir(dest) < 0) { INTON; return -1; } gotpwd = updatepwd(NULL); /* only do cd -P, no "pretend" -L mode */ INTON; if (print && (iflag || posix)) out1fmt("%s\n", gotpwd ? curdir : dest); return gotpwd || !eopt ? 0 : 1; } /* * Get the next component of the path name pointed to by cdcomppath. * This routine overwrites the string pointed to by cdcomppath. */ STATIC char * getcomponent(void) { 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 bool updatepwd(const 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(). Or we simply don't trust what we had. */ if (dir == NULL || curdir == NULL) { if (prevdir) ckfree(prevdir); INTOFF; prevdir = curdir; curdir = NULL; getpwd(1); INTON; if (curdir) { setvar("OLDPWD", prevdir, VEXPORT); setvar("PWD", curdir, VEXPORT); return true; } else unsetvar("PWD", 0); return false; } /* XXX none of the following code is ever executed any more */ 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("OLDPWD", prevdir, VEXPORT); setvar("PWD", curdir, VEXPORT); INTON; return true; } /* * Test whether we are currently in the direcory given * (provided it is given, and is absolute) * ie: determine if path is fully qualified pathname of "." */ STATIC bool is_curdir(const char *path) { struct stat stdot, stpath; return path != NULL && *path == '/' && stat(".", &stdot) != -1 && stat(path, &stpath) != -1 && stdot.st_dev == stpath.st_dev && stdot.st_ino == stpath.st_ino; } /* * 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); #if 0 /* posix has been changed to forbid this */ setvar("OLDPWD", prevdir, VEXPORT); setvar("PWD", curdir, VEXPORT); #endif if (!is_curdir(curdir)) { find_curdir(1); if (curdir == NULL) error("Unable to find current directory"); } out1str(curdir); out1c('\n'); return 0; } void initpwd(void) { getpwd(1); if (curdir) setvar("PWD", curdir, VEXPORT); else sh_warnx("Cannot determine current working directory"); } #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; static int first = 1; if (curdir) return; if (first) { first = 0; pwd = getenv("PWD"); if (is_curdir(pwd)) { 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. * XXX That's not actually the problem, a process created and * XXX destroyed that we know nothing about is harmless. The * XXX problem is that old popen() implementations would use * XXX wait(2) to await completion of the command, and that might * XXX collect (and ignore) our children. As long as we are * XXX confident that popen() uses waitpid() (or the equv) there * XXX would not be a problem. But how do we know that? * 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) for (i = MAXPWD;; i *= 2) { pwd = stalloc(i); if (getcwd(pwd, i) != NULL) { curdir = savestr(pwd); stunalloc(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(NULL, 1); if (forkshell(jp, NULL, FORK_NOJOB) == 0) { (void) close(pip[0]); movefd(pip[1], 1); (void) execl("/bin/pwd", "pwd", (char *)0); error("Cannot exec /bin/pwd"); } (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); stunalloc(pwd); return; } #endif }