/*
 * Copyright (c) 2000, Boris Popov
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    This product includes software developed by Boris Popov.
 * 4. Neither the name of the author nor the names of any co-contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
 *
 * $FreeBSD$
 */

#include <sys/param.h>
#include <sys/exec.h>
#include <sys/queue.h>
#include <sys/kernel.h>
#include <sys/reboot.h>
#include <sys/linker.h>
#include <sys/stat.h>
#include <sys/module.h>
#define FREEBSD_ELF
#include <link.h>
#include <err.h>
#include <fts.h>
#include <string.h>
#include <machine/elf.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>

#include "ef.h"

#define	MAXRECSIZE	1024
#define check(val)	if ((error = (val)) != 0) break

#ifndef min
#define	min(a,b)	(((a)<(b)) ? (a) : (b))
#endif

struct mod_info {
	char*	mi_name;
	int	mi_ver;
	SLIST_ENTRY(mod_info) mi_next;
};

#ifdef notnow
struct kld_info {
	char*	k_filename;
	SLIST_HEAD(mod_list_head, mod_info) k_modules;
	SLIST_ENTRY(kld_info) k_next;
};

SLIST_HEAD(kld_list_head, kld_info) kldlist;
#endif

static int dflag, verbose;

FILE *fxref;

static const char *xref_file = "linker.hints";

static char recbuf[MAXRECSIZE];
static int recpos, reccnt;

void maketempfile(char *, const char *);
static void usage(void);

static void
intalign(void)
{
	recpos = (recpos + sizeof(int) - 1) & ~(sizeof(int) - 1);
}

static void
record_start(void)
{
	recpos = 0;
	memset(recbuf, 0, MAXRECSIZE);
}

static int
record_end(void)
{
	if (dflag || recpos == 0)
		return 0;
	reccnt++;
	intalign();
	fwrite(&recpos, sizeof(recpos), 1, fxref);
	return fwrite(recbuf, recpos, 1, fxref) != 1 ? errno : 0;
}

static int
record_buf(const void *buf, int size)
{
	if (MAXRECSIZE - recpos < size)
		errx(1, "record buffer overflow");
	memcpy(recbuf + recpos, buf, size);
	recpos += size;
	return 0;
}

static int
record_int(int val)
{
	intalign();
	return record_buf(&val, sizeof(val));
}

static int
record_byte(u_char val)
{
	return record_buf(&val, sizeof(val));
}

static int
record_string(const char *str)
{
	int len = strlen(str);
	int error;

	if (dflag)
		return 0;
	error = record_byte(len);
	if (error)
		return error;
	return record_buf(str, len);
}

static int
parse_entry(struct mod_metadata *md, const char *cval,
    struct elf_file *ef, const char *kldname)
{
	struct mod_depend mdp;
	struct mod_version mdv;
	Elf_Off data = (Elf_Off)md->md_data;
	int error = 0;

	record_start();
	switch (md->md_type) {
	case MDT_DEPEND:
		if (!dflag)
			break;
		check(ef_seg_read(ef, data, sizeof(mdp), (void**)&mdp));
		printf("  depends on %s.%d (%d,%d)\n", cval,
		    mdp.md_ver_preferred, mdp.md_ver_minimum, mdp.md_ver_maximum);
		break;
	case MDT_VERSION:
		check(ef_seg_read(ef, data, sizeof(mdv), (void**)&mdv));
		record_int(MDT_VERSION);
		record_string(cval);
		record_int(mdv.mv_version);
		record_string(kldname);
		if (!dflag)
			break;
		printf("  interface %s.%d\n", cval, mdv.mv_version);
		break;
	case MDT_MODULE:
		record_int(MDT_MODULE);
		record_string(cval);
		record_string(kldname);
		if (!dflag)
			break;
		printf("  module %s\n", cval);
		break;
	default:
		warnx("unknown metdata record %d in file %s", md->md_type, kldname);
	}
	if (!error)
		record_end();
	return error;
}

static int
read_kld(char *filename, char *kldname)
{
	struct mod_metadata md;
	struct elf_file ef;
/*	struct kld_info *kip;
	struct mod_info *mip;*/
	void **p, **orgp;
	int error, nmlen;
	long start, finish, entries;
	Elf_Sym *sym;
	char kldmodname[MAXMODNAME + 1], cval[MAXMODNAME + 1], *cp;

	if (verbose || dflag)
		printf("%s\n", filename);
	error = ef_open(filename, &ef, verbose);
	if (error)
		return error;
	if (ef.ef_type != EFT_KLD && ef.ef_type != EFT_KERNEL)  {
		ef_close(&ef);
		return 0;
	}
	if (!dflag) {
		cp = strrchr(kldname, '.');
		nmlen = cp ? min(MAXMODNAME, cp - kldname) : 
		    min(MAXMODNAME, strlen(kldname));
		strncpy(kldmodname, kldname, nmlen);
		kldmodname[nmlen] = '\0';
/*		fprintf(fxref, "%s:%s:%d\n", kldmodname, kldname, 0);*/
	}
	do {
		check(ef_lookup_symbol(&ef, "__start_set_" MDT_SETNAME, &sym));
		start = sym->st_value;
		check(ef_lookup_symbol(&ef, "__stop_set_" MDT_SETNAME, &sym));
		finish = sym->st_value;
		entries = (finish - start) / sizeof(void *);
		check(ef_seg_read_entry_rel(&ef, start, sizeof(*p) * entries,
		    (void**)&p));
		orgp = p;
		while(entries--) {
			check(ef_seg_read_rel(&ef, (Elf_Off)*p, sizeof(md), &md));
			p++;
			check(ef_seg_read(&ef, (Elf_Off)md.md_cval, sizeof(cval), cval));
			cval[MAXMODNAME] = '\0';
			parse_entry(&md, cval, &ef, kldname);
		}
		if (error)
			warnc(error, "error while reading %s", filename);
		free(orgp);
	} while(0);
	ef_close(&ef);
	return error;
}

void
maketempfile(char *dest, const char *root)
{
	char *p;

	strncpy(dest, root, MAXPATHLEN - 1);
	dest[MAXPATHLEN] = '\0';

	if ((p = strrchr(dest, '/')) != 0)
		p++;
	else
		p = dest;
	strcpy(p, "lhint.XXXXXX");
	if (mkstemp(dest) == -1)
		err(1, "%s", dest);
}

static char xrefname[MAXPATHLEN], tempname[MAXPATHLEN];

int
main(int argc, char *argv[])
{
	FTS *ftsp;
	FTSENT *p;
	int opt, fts_options, ival;

	fts_options = FTS_PHYSICAL;
/*	SLIST_INIT(&kldlist);*/

	while ((opt = getopt(argc, argv, "Rdf:v")) != -1) {
		switch (opt) {
		case 'd':
			dflag = 1;
			break;
		case 'f':
			xref_file = optarg;
			break;
		case 'v':
			verbose++;
			break;
		case 'R':
			fts_options |= FTS_COMFOLLOW;
			break;
		default:
			usage();
			/* NOTREACHED */
		}
	}
	if (argc - optind < 1)
		usage();
	argc -= optind;
	argv += optind;

	ftsp = fts_open(argv, fts_options, 0);
	if (ftsp == NULL)
		exit(1);

	for (;;) {
		p = fts_read(ftsp);
		if ((p == NULL || p->fts_info == FTS_D) && !dflag && fxref) {
			fclose(fxref);
			if (reccnt) {
				rename(tempname, xrefname);
			} else {
				unlink(tempname);
				unlink(xrefname);
			}
		}
		if (p == NULL)
			break;
		if (p && p->fts_info == FTS_D && !dflag) {
			snprintf(xrefname, sizeof(xrefname), "%s/%s",
			    ftsp->fts_path, xref_file);
			maketempfile(tempname, ftsp->fts_path);
			fxref = fopen(tempname, "w+t");
			if (fxref == NULL)
				err(1, "can't create %s", tempname);
			ival = 1;
			fwrite(&ival, sizeof(ival), 1, fxref);
			reccnt = 0;
		}
		if (p->fts_info != FTS_F)
			continue;
		read_kld(p->fts_path, p->fts_name);
	}
	fts_close(ftsp);
	return 0;
}

static void
usage(void)
{

	fprintf(stderr, "%s\n",
	    "usage: kldxref [-Rdv] [-f hintfile] path [path..]"
	);
	exit(1);
}