/*      $OpenBSD: ex_cd.c,v 1.15 2016/05/27 09:18:12 martijn Exp $      */

/*-
 * Copyright (c) 1992, 1993, 1994
 *      The Regents of the University of California.  All rights reserved.
 * Copyright (c) 1992, 1993, 1994, 1995, 1996
 *      Keith Bostic.  All rights reserved.
 *
 * See the LICENSE file for redistribution information.
 */

#include "config.h"

#include <sys/queue.h>

#include <bitstring.h>
#include <errno.h>
#include <limits.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "../common/common.h"

/*
 * ex_cd -- :cd[!] [directory]
 *      Change directories.
 *
 * PUBLIC: int ex_cd(SCR *, EXCMD *);
 */
int
ex_cd(SCR *sp, EXCMD *cmdp)
{
        struct passwd *pw;
        ARGS *ap;
        CHAR_T savech;
        char *dir, *p, *t;
        char buf[PATH_MAX * 2];

        /*
         * !!!
         * Historic practice is that the cd isn't attempted if the file has
         * been modified, unless its name begins with a leading '/' or the
         * force flag is set.
         */
        if (F_ISSET(sp->ep, F_MODIFIED) &&
            !FL_ISSET(cmdp->iflags, E_C_FORCE) && sp->frp->name[0] != '/') {
                msgq(sp, M_ERR,
    "File modified since last complete write; write or use ! to override");
                return (1);
        }

        switch (cmdp->argc) {
        case 0:
                /* If no argument, change to the user's home directory. */
                if ((dir = getenv("HOME")) == NULL || *dir == '\0') {
                        if ((pw = getpwuid(getuid())) == NULL ||
                            pw->pw_dir == NULL || pw->pw_dir[0] == '\0') {
                                msgq(sp, M_ERR,
                           "Unable to find home directory location");
                                return (1);
                        }
                        dir = pw->pw_dir;
                }
                break;
        case 1:
                dir = cmdp->argv[0]->bp;
                break;
        default:
                abort();
        }

        /*
         * Try the current directory first.  If this succeeds, don't display
         * a message, vi didn't historically, and it should be obvious to the
         * user where they are.
         */
        if (!chdir(dir))
                return (0);

        /*
         * If moving to the user's home directory, or, the path begins with
         * "/", "./" or "../", it's the only place we try.
         */
        if (cmdp->argc == 0 ||
            (ap = cmdp->argv[0])->bp[0] == '/' ||
            (ap->len == 1 && ap->bp[0] == '.') ||
            (ap->len >= 2 && ap->bp[0] == '.' && ap->bp[1] == '.' &&
            (ap->bp[2] == '/' || ap->bp[2] == '\0')))
                goto err;

        /* Try the O_CDPATH option values. */
        for (p = t = O_STR(sp, O_CDPATH);; ++p)
                if (*p == '\0' || *p == ':') {
                        /*
                         * Empty strings specify ".".  The only way to get an
                         * empty string is a leading colon, colons in a row,
                         * or a trailing colon.  Or, to put it the other way,
                         * if the length is 1 or less, then we're dealing with
                         * ":XXX", "XXX::XXXX" , "XXX:", or "".  Since we've
                         * already tried dot, we ignore them all.
                         */
                        if (t < p - 1) {
                                savech = *p;
                                *p = '\0';
                                (void)snprintf(buf,
                                    sizeof(buf), "%s/%s", t, dir);
                                *p = savech;
                                if (!chdir(buf)) {
                                        if (getcwd(buf, sizeof(buf)) != NULL)
                msgq_str(sp, M_INFO, buf, "New current directory: %s");
                                        return (0);
                                }
                        }
                        t = p + 1;
                        if (*p == '\0')
                                break;
                }

err:    msgq_str(sp, M_SYSERR, dir, "%s");
        return (1);
}