/* $NetBSD: findcc.c,v 1.10 2021/08/20 06:36:10 rillig Exp $ */

/*-
 * Copyright (c) 1999 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Matthias Scheler.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 */

#if HAVE_NBTOOL_CONFIG_H
#include "nbtool_config.h"
#endif

#include <sys/cdefs.h>
#if !defined(lint)
__COPYRIGHT("@(#) Copyright (c) 1999 The NetBSD Foundation, Inc.\
 All rights reserved.");
__RCSID("$NetBSD: findcc.c,v 1.10 2021/08/20 06:36:10 rillig Exp $");
#endif /* not lint */

#include <sys/param.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "findcc.h"

char *
findcc(const char *progname)
{
        char *cc;
        const char *path, *dir;
        char buffer[MAXPATHLEN];
        size_t progname_len, dir_len;

        progname_len = strcspn(progname, " ");

        if (memchr(progname, '/', progname_len) != NULL) {
                if ((cc = strndup(progname, progname_len)) == NULL)
                        return NULL;
                if (access(cc, X_OK) == 0)
                        return cc;
                free(cc);
                return NULL;
        }

        if ((path = getenv("PATH")) == NULL)
                return NULL;

        for (dir = path; *dir != '\0'; ) {
                dir_len = strcspn(dir, ":");

                if ((size_t)snprintf(buffer, sizeof(buffer), "%.*s/%.*s",
                        (int)dir_len, dir, (int)progname_len, progname)
                    < sizeof(buffer)
                    && access(buffer, X_OK) == 0)
                        return strdup(buffer);

                dir += dir_len;
                if (*dir == ':')
                        dir++;
        }

        return NULL;
}