/*	$Id: manpath.c,v 1.15 2014/04/23 21:06:41 schwarze Exp $ */
/*
 * Copyright (c) 2011 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.
 */
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#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 *);
static	void	 manpath_parseline(struct manpaths *, char *);

void
manpath_parse(struct manpaths *dirs, const char *file,
		char *defp, char *auxp)
{
#ifdef	USE_MANPATH
	char		 cmd[(PATH_MAX * 3) + 20];
	FILE		*stream;
	char		*buf;
	size_t		 sz, bsz;

	strlcpy(cmd, "manpath", sizeof(cmd));
	if (file) {
		strlcat(cmd, " -C ", sizeof(cmd));
		strlcat(cmd, file, sizeof(cmd));
	}
	if (auxp) {
		strlcat(cmd, " -m ", sizeof(cmd));
		strlcat(cmd, auxp, sizeof(cmd));
	}
	if (defp) {
		strlcat(cmd, " -M ", sizeof(cmd));
		strlcat(cmd, defp, sizeof(cmd));
	}

	/* Open manpath(1).  Ignore errors. */

	stream = popen(cmd, "r");
	if (NULL == stream)
		return;

	buf = NULL;
	bsz = 0;

	/* Read in as much output as we can. */

	do {
		buf = mandoc_realloc(buf, bsz + 1024);
		sz = fread(buf + bsz, 1, 1024, stream);
		bsz += sz;
	} while (sz > 0);

	if ( ! ferror(stream) && feof(stream) &&
			bsz && '\n' == buf[bsz - 1]) {
		buf[bsz - 1] = '\0';
		manpath_parseline(dirs, buf);
	}

	free(buf);
	pclose(stream);
#else
	char		*insert;

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

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

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

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

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

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

	if (NULL == path)
		return;

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

/*
 * 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)
{
	char		 buf[PATH_MAX];
	char		*cp;
	size_t		 i;

	if (NULL == (cp = realpath(dir, buf)))
		return;

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

	fclose(stream);
}