/*	$OpenBSD: manpath.c,v 1.11 2014/11/18 19:40:38 schwarze Exp $ */
/*
 * Copyright (c) 2011, 2014 Ingo Schwarze <schwarze@openbsd.org>
 * Copyright (c) 2011 Kristaps Dzonsons <kristaps@bsd.lv>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
#include <sys/types.h>
#include <sys/stat.h>

#include <assert.h>
#include <ctype.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "mandoc_aux.h"
#include "manpath.h"

#define MAN_CONF_FILE	"/etc/man.conf"
#define MAN_CONF_KEY	"_whatdb"

static	void	 manpath_add(struct manpaths *, const char *, int);
static	void	 manpath_parseline(struct manpaths *, char *, int);

void
manpath_parse(struct manpaths *dirs, const char *file,
		char *defp, char *auxp)
{
	char		*insert;

	/* Always prepend -m. */
	manpath_parseline(dirs, auxp, 1);

	/* If -M is given, it overrides everything else. */
	if (NULL != defp) {
		manpath_parseline(dirs, defp, 1);
		return;
	}

	/* MANPATH and man.conf(5) cooperate. */
	defp = getenv("MANPATH");
	if (NULL == file)
		file = MAN_CONF_FILE;

	/* No MANPATH; use man.conf(5) only. */
	if (NULL == defp || '\0' == defp[0]) {
		manpath_manconf(dirs, file);
		return;
	}

	/* Prepend man.conf(5) to MANPATH. */
	if (':' == defp[0]) {
		manpath_manconf(dirs, file);
		manpath_parseline(dirs, defp, 0);
		return;
	}

	/* Append man.conf(5) to MANPATH. */
	if (':' == defp[strlen(defp) - 1]) {
		manpath_parseline(dirs, defp, 0);
		manpath_manconf(dirs, file);
		return;
	}

	/* Insert man.conf(5) into MANPATH. */
	insert = strstr(defp, "::");
	if (NULL != insert) {
		*insert++ = '\0';
		manpath_parseline(dirs, defp, 0);
		manpath_manconf(dirs, file);
		manpath_parseline(dirs, insert + 1, 0);
		return;
	}

	/* MANPATH overrides man.conf(5) completely. */
	manpath_parseline(dirs, defp, 0);
}

/*
 * Parse a FULL pathname from a colon-separated list of arrays.
 */
static void
manpath_parseline(struct manpaths *dirs, char *path, int complain)
{
	char	*dir;

	if (NULL == path)
		return;

	for (dir = strtok(path, ":"); dir; dir = strtok(NULL, ":"))
		manpath_add(dirs, dir, complain);
}

/*
 * Add a directory to the array, ignoring bad directories.
 * Grow the array one-by-one for simplicity's sake.
 */
static void
manpath_add(struct manpaths *dirs, const char *dir, int complain)
{
	char		 buf[PATH_MAX];
	struct stat	 sb;
	char		*cp;
	size_t		 i;

	if (NULL == (cp = realpath(dir, buf))) {
		if (complain) {
			fputs("manpath: ", stderr);
			perror(dir);
		}
		return;
	}

	for (i = 0; i < dirs->sz; i++)
		if (0 == strcmp(dirs->paths[i], dir))
			return;

	if (stat(cp, &sb) == -1) {
		if (complain) {
			fputs("manpath: ", stderr);
			perror(dir);
		}
		return;
	}

	dirs->paths = mandoc_reallocarray(dirs->paths,
	    dirs->sz + 1, sizeof(char *));

	dirs->paths[dirs->sz++] = mandoc_strdup(cp);
}

void
manpath_free(struct manpaths *p)
{
	size_t		 i;

	for (i = 0; i < p->sz; i++)
		free(p->paths[i]);

	free(p->paths);
}

void
manpath_manconf(struct manpaths *dirs, const char *file)
{
	FILE		*stream;
	char		*p, *q;
	size_t		 len, keysz;

	keysz = strlen(MAN_CONF_KEY);
	assert(keysz > 0);

	if (NULL == (stream = fopen(file, "r")))
		return;

	while (NULL != (p = fgetln(stream, &len))) {
		if (0 == len || '\n' != p[--len])
			break;
		p[len] = '\0';
		while (isspace((unsigned char)*p))
			p++;
		if (strncmp(MAN_CONF_KEY, p, keysz))
			continue;
		p += keysz;
		while (isspace((unsigned char)*p))
			p++;
		if ('\0' == *p)
			continue;
		if (NULL == (q = strrchr(p, '/')))
			continue;
		*q = '\0';
		manpath_add(dirs, p, 0);
	}

	fclose(stream);
}