#
# This file and its contents are supplied under the terms of the
# Common Development and Distribution License ("CDDL"), version 1.0.
# You may only use this file in accordance with the terms of version
# 1.0 of the CDDL.
#
# A full copy of the text of the CDDL should have accompanied this
# source.  A copy of the CDDL is also available via the Internet at
# http://www.illumos.org/license/CDDL.
#

#
# Copyright 2022 Oxide Computer Company
# Copyright 2023 OmniOS Community Edition (OmniOSce) Association.
#

PROG= which

include ../Makefile.cmd
include ../Makefile.cmd.64
include ../Makefile.ctf

OBJS= which.o

CSTD= $(CSTD_GNU99)

.KEEP_STATE:

$(PROG): $(OBJS)
	$(LINK.c) -o $@ $(OBJS) $(LDLIBS)
	$(POST_PROCESS)

all: $(PROG)

install: all $(ROOTPROG)

clean:
	$(RM) $(OBJS)

include ../Makefile.targ
Copyright (c) 2000 Dan Papasian.  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. The name of the author may not be used to endorse or promote products
   derived from this software without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
PORTIONS OF WHICH COMMAND FUNCTIONALITY
/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 2000 Dan Papasian.  All rights reserved.
 * Copyright 2023 OmniOS Community Edition (OmniOSce) Association.
 *
 * 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. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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/fcntl.h>
#include <sys/param.h>
#include <sys/stat.h>
#include <err.h>
#include <limits.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#define	EXIT_USAGE	2

static void	usage(void) __NORETURN;
static bool	print_matches(char *, const char *const);

static bool	silent = false;
static bool	allpaths = false;

int
main(int argc, char **argv)
{
	char *p, *path;
	size_t pathlen;
	int opt, status;

	status = EXIT_SUCCESS;

	while ((opt = getopt(argc, argv, "as")) != -1) {
		switch (opt) {
		case 'a':
			allpaths = true;
			break;
		case 's':
			silent = true;
			break;
		default:
			usage();
			break;
		}
	}

	argv += optind;
	argc -= optind;

	if (argc == 0)
		exit(EXIT_SUCCESS);

	if ((p = getenv("PATH")) == NULL)
		errx(EXIT_FAILURE, "Could not find PATH in environment");

	pathlen = strlen(p);
	path = strdup(p);

	if (path == NULL)
		err(EXIT_FAILURE, "Failed to duplicate PATH");

	while (argc > 0) {
		memcpy(path, p, pathlen + 1);

		if (strlen(*argv) >= FILENAME_MAX) {
			status = EXIT_FAILURE;

			warnx("operand too long '%s'", *argv);
		} else if (!print_matches(path, *argv)) {
			status = EXIT_FAILURE;

			if (!silent) {
				(void) printf("no %s in", *argv);

				if (pathlen > 0) {
					char *q = path;
					const char *d;

					memcpy(q, p, pathlen + 1);

					while ((d = strsep(&q, ":")) != NULL) {
						(void) printf(" %s",
						    *d == '\0' ? "." : d);
					}
				}

				(void) printf("\n");
			}
		}

		argv++;
		argc--;
	}

	free(path);
	exit(status);
}

static void
usage(void)
{
	(void) fprintf(stderr, "usage: which [-as] program ...\n");
	exit(EXIT_USAGE);
}

static bool
is_there(const char *const candidate)
{
	struct stat fin;

	if (faccessat(AT_FDCWD, candidate, X_OK, AT_EACCESS) == 0 &&
	    stat(candidate, &fin) == 0 &&
	    S_ISREG(fin.st_mode)) {
		if (!silent)
			printf("%s\n", candidate);

		return (true);
	}

	return (false);
}

static bool
print_matches(char *path, const char *const filename)
{
	char candidate[PATH_MAX];
	const char *d;
	bool found = false;

	if (strchr(filename, '/') != NULL)
		return (is_there(filename));

	while ((d = strsep(&path, ":")) != NULL) {
		if (*d == '\0')
			d = ".";
		if (snprintf(candidate, sizeof (candidate), "%s/%s", d,
		    filename) >= (int)sizeof (candidate))
			continue;
		if (is_there(candidate)) {
			found = true;
			if (!allpaths)
				break;
		}
	}

	return (found);
}