/*      $NetBSD: whereis.c,v 1.22 2025/06/01 15:45:31 jschauma Exp $    */

/*-
 * Copyright (c) 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * 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
__COPYRIGHT("@(#) Copyright (c) 1993\
 The Regents of the University of California.  All rights reserved.");
#endif /* not lint */

#ifndef lint
#if 0
static char sccsid[] = "@(#)whereis.c   8.3 (Berkeley) 5/4/95";
#endif
__RCSID("$NetBSD: whereis.c,v 1.22 2025/06/01 15:45:31 jschauma Exp $");
#endif /* not lint */

#include <sys/param.h>
#include <sys/stat.h>
#include <sys/sysctl.h>

#include <err.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

static void usage(void) __dead;

int
main(int argc, char *argv[])
{
        struct stat sb;
        size_t len;
        int ch, mib[2];
        char *p, *std, path[MAXPATHLEN];
        const char *t;
        int which = strcmp(getprogname(), "which") == 0;
        int useenvpath = which, found = 0;
        gid_t egid = getegid();
        uid_t euid = geteuid();

        /* To make access(2) do what we want */
        if (setregid(egid, egid) == -1)
                err(1, "Can't set gid to %lu", (unsigned long)egid);
        if (setreuid(euid, euid) == -1)
                err(1, "Can't set uid to %lu", (unsigned long)euid);

        while ((ch = getopt(argc, argv, "ap")) != -1)
                switch (ch) {
                case 'a':
                        which = 0;
                        break;
                case 'p':
                        useenvpath = 1; /* use environment for PATH */
                        break;

                case '?':
                default:
                        usage();
                }
        argc -= optind;
        argv += optind;

        if (argc == 0)
                usage();

        if (useenvpath) {
                if ((std = getenv("PATH")) == NULL)
                        errx(1, "PATH environment variable is not set");
        } else {
                /* Retrieve the standard path. */
                mib[0] = CTL_USER;
                mib[1] = USER_CS_PATH;
                if (sysctl(mib, 2, NULL, &len, NULL, 0) == -1)
                        err(1, "sysctl: user.cs_path");
                if (len == 0)
                        errx(1, "sysctl: user.cs_path (zero length)");
                if ((std = malloc(len)) == NULL)
                        err(1, NULL);
                if (sysctl(mib, 2, std, &len, NULL, 0) == -1)
                        err(1, "sysctl: user.cs_path");
        }

        /* For each path, for each program... */
        for (; *argv; ++argv) {
                if (**argv == '/') {
                        if (stat(*argv, &sb) == -1)
                                continue; /* next argv */
                        if (!S_ISREG(sb.st_mode))
                                continue; /* next argv */
                        if (access(*argv, X_OK) == -1)
                                continue; /* next argv */
                        (void)printf("%s\n", *argv);
                        found++;
                        if (which)
                                continue; /* next argv */
                } else for (p = std; p; ) {
                        t = p;
                        if ((p = strchr(p, ':')) != NULL) {
                                *p = '\0';
                                if (t == p)
                                        t = ".";
                        } else
                                if (strlen(t) == 0)
                                        t = ".";
                        (void)snprintf(path, sizeof(path), "%s/%s", t, *argv);
                        len = snprintf(path, sizeof(path), "%s/%s", t, *argv);
                        if (p)
                                *p++ = ':';
                        if (len >= sizeof(path))
                                continue; /* next p */
                        if (stat(path, &sb) == -1)
                                continue; /* next p */
                        if (!S_ISREG(sb.st_mode))
                                continue; /* next p */
                        if (access(path, X_OK) == -1)
                                continue; /* next p */
                        (void)printf("%s\n", path);
                        found++;
                        if (which)
                                break; /* next argv */
                }
        }
        
        return ((found == 0) ? 3 : ((found >= argc) ? 0 : 2));
}

static void
usage(void)
{

        (void)fprintf(stderr, "Usage: %s [-ap] program [...]\n", getprogname());
        exit(1);
}