#include <netinet/in.h>
#include <stdint.h>
#include <ctype.h>
#include <errno.h>
#include <string.h>
#include "modpost.h"

/* Parse tag=value strings from .modinfo section */
static char *next_string(char *string, unsigned long *secsize)
{
	/* Skip non-zero chars */
	while (string[0]) {
		string++;
		if ((*secsize)-- <= 1)
			return NULL;
	}

	/* Skip any zero padding. */
	while (!string[0]) {
		string++;
		if ((*secsize)-- <= 1)
			return NULL;
	}
	return string;
}

static char *get_modinfo(void *modinfo, unsigned long modinfo_len,
			 const char *tag)
{
	char *p;
	unsigned int taglen = strlen(tag);
	unsigned long size = modinfo_len;

	for (p = modinfo; p; p = next_string(p, &size)) {
		if (strncmp(p, tag, taglen) == 0 && p[taglen] == '=')
			return p + taglen + 1;
	}
	return NULL;
}

/*
 * Stolen form Cryptographic API.
 *
 * MD4 Message Digest Algorithm (RFC1320).
 *
 * Implementation derived from Andrew Tridgell and Steve French's
 * CIFS MD4 implementation, and the cryptoapi implementation
 * originally based on the public domain implementation written
 * by Colin Plumb in 1993.
 *
 * Copyright (c) Andrew Tridgell 1997-1998.
 * Modified by Steve French (sfrench@us.ibm.com) 2002
 * Copyright (c) Cryptoapi developers.
 * Copyright (c) 2002 David S. Miller (davem@redhat.com)
 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 */
#define MD4_DIGEST_SIZE		16
#define MD4_HMAC_BLOCK_SIZE	64
#define MD4_BLOCK_WORDS		16
#define MD4_HASH_WORDS		4

struct md4_ctx {
	uint32_t hash[MD4_HASH_WORDS];
	uint32_t block[MD4_BLOCK_WORDS];
	uint64_t byte_count;
};

static inline uint32_t lshift(uint32_t x, unsigned int s)
{
	x &= 0xFFFFFFFF;
	return ((x << s) & 0xFFFFFFFF) | (x >> (32 - s));
}

static inline uint32_t F(uint32_t x, uint32_t y, uint32_t z)
{
	return (x & y) | ((~x) & z);
}

static inline uint32_t G(uint32_t x, uint32_t y, uint32_t z)
{
	return (x & y) | (x & z) | (y & z);
}

static inline uint32_t H(uint32_t x, uint32_t y, uint32_t z)
{
	return x ^ y ^ z;
}

#define ROUND1(a,b,c,d,k,s) (a = lshift(a + F(b,c,d) + k, s))
#define ROUND2(a,b,c,d,k,s) (a = lshift(a + G(b,c,d) + k + (uint32_t)0x5A827999,s))
#define ROUND3(a,b,c,d,k,s) (a = lshift(a + H(b,c,d) + k + (uint32_t)0x6ED9EBA1,s))

/* XXX: this stuff can be optimized */
static inline void le32_to_cpu_array(uint32_t *buf, unsigned int words)
{
	while (words--) {
		*buf = ntohl(*buf);
		buf++;
	}
}

static inline void cpu_to_le32_array(uint32_t *buf, unsigned int words)
{
	while (words--) {
		*buf = htonl(*buf);
		buf++;
	}
}

static void md4_transform(uint32_t *hash, uint32_t const *in)
{
	uint32_t a, b, c, d;

	a = hash[0];
	b = hash[1];
	c = hash[2];
	d = hash[3];

	ROUND1(a, b, c, d, in[0], 3);
	ROUND1(d, a, b, c, in[1], 7);
	ROUND1(c, d, a, b, in[2], 11);
	ROUND1(b, c, d, a, in[3], 19);
	ROUND1(a, b, c, d, in[4], 3);
	ROUND1(d, a, b, c, in[5], 7);
	ROUND1(c, d, a, b, in[6], 11);
	ROUND1(b, c, d, a, in[7], 19);
	ROUND1(a, b, c, d, in[8], 3);
	ROUND1(d, a, b, c, in[9], 7);
	ROUND1(c, d, a, b, in[10], 11);
	ROUND1(b, c, d, a, in[11], 19);
	ROUND1(a, b, c, d, in[12], 3);
	ROUND1(d, a, b, c, in[13], 7);
	ROUND1(c, d, a, b, in[14], 11);
	ROUND1(b, c, d, a, in[15], 19);

	ROUND2(a, b, c, d,in[ 0], 3);
	ROUND2(d, a, b, c, in[4], 5);
	ROUND2(c, d, a, b, in[8], 9);
	ROUND2(b, c, d, a, in[12], 13);
	ROUND2(a, b, c, d, in[1], 3);
	ROUND2(d, a, b, c, in[5], 5);
	ROUND2(c, d, a, b, in[9], 9);
	ROUND2(b, c, d, a, in[13], 13);
	ROUND2(a, b, c, d, in[2], 3);
	ROUND2(d, a, b, c, in[6], 5);
	ROUND2(c, d, a, b, in[10], 9);
	ROUND2(b, c, d, a, in[14], 13);
	ROUND2(a, b, c, d, in[3], 3);
	ROUND2(d, a, b, c, in[7], 5);
	ROUND2(c, d, a, b, in[11], 9);
	ROUND2(b, c, d, a, in[15], 13);

	ROUND3(a, b, c, d,in[ 0], 3);
	ROUND3(d, a, b, c, in[8], 9);
	ROUND3(c, d, a, b, in[4], 11);
	ROUND3(b, c, d, a, in[12], 15);
	ROUND3(a, b, c, d, in[2], 3);
	ROUND3(d, a, b, c, in[10], 9);
	ROUND3(c, d, a, b, in[6], 11);
	ROUND3(b, c, d, a, in[14], 15);
	ROUND3(a, b, c, d, in[1], 3);
	ROUND3(d, a, b, c, in[9], 9);
	ROUND3(c, d, a, b, in[5], 11);
	ROUND3(b, c, d, a, in[13], 15);
	ROUND3(a, b, c, d, in[3], 3);
	ROUND3(d, a, b, c, in[11], 9);
	ROUND3(c, d, a, b, in[7], 11);
	ROUND3(b, c, d, a, in[15], 15);

	hash[0] += a;
	hash[1] += b;
	hash[2] += c;
	hash[3] += d;
}

static inline void md4_transform_helper(struct md4_ctx *ctx)
{
	le32_to_cpu_array(ctx->block, sizeof(ctx->block) / sizeof(uint32_t));
	md4_transform(ctx->hash, ctx->block);
}

static void md4_init(struct md4_ctx *mctx)
{
	mctx->hash[0] = 0x67452301;
	mctx->hash[1] = 0xefcdab89;
	mctx->hash[2] = 0x98badcfe;
	mctx->hash[3] = 0x10325476;
	mctx->byte_count = 0;
}

static void md4_update(struct md4_ctx *mctx,
		       const unsigned char *data, unsigned int len)
{
	const uint32_t avail = sizeof(mctx->block) - (mctx->byte_count & 0x3f);

	mctx->byte_count += len;

	if (avail > len) {
		memcpy((char *)mctx->block + (sizeof(mctx->block) - avail),
		       data, len);
		return;
	}

	memcpy((char *)mctx->block + (sizeof(mctx->block) - avail),
	       data, avail);

	md4_transform_helper(mctx);
	data += avail;
	len -= avail;

	while (len >= sizeof(mctx->block)) {
		memcpy(mctx->block, data, sizeof(mctx->block));
		md4_transform_helper(mctx);
		data += sizeof(mctx->block);
		len -= sizeof(mctx->block);
	}

	memcpy(mctx->block, data, len);
}

static void md4_final_ascii(struct md4_ctx *mctx, char *out, unsigned int len)
{
	const unsigned int offset = mctx->byte_count & 0x3f;
	char *p = (char *)mctx->block + offset;
	int padding = 56 - (offset + 1);

	*p++ = 0x80;
	if (padding < 0) {
		memset(p, 0x00, padding + sizeof (uint64_t));
		md4_transform_helper(mctx);
		p = (char *)mctx->block;
		padding = 56;
	}

	memset(p, 0, padding);
	mctx->block[14] = mctx->byte_count << 3;
	mctx->block[15] = mctx->byte_count >> 29;
	le32_to_cpu_array(mctx->block, (sizeof(mctx->block) -
	                  sizeof(uint64_t)) / sizeof(uint32_t));
	md4_transform(mctx->hash, mctx->block);
	cpu_to_le32_array(mctx->hash, sizeof(mctx->hash) / sizeof(uint32_t));

	snprintf(out, len, "%08X%08X%08X%08X",
		 mctx->hash[0], mctx->hash[1], mctx->hash[2], mctx->hash[3]);
}

static inline void add_char(unsigned char c, struct md4_ctx *md)
{
	md4_update(md, &c, 1);
}

static int parse_string(const char *file, unsigned long len,
			struct md4_ctx *md)
{
	unsigned long i;

	add_char(file[0], md);
	for (i = 1; i < len; i++) {
		add_char(file[i], md);
		if (file[i] == '"' && file[i-1] != '\\')
			break;
	}
	return i;
}

static int parse_comment(const char *file, unsigned long len)
{
	unsigned long i;

	for (i = 2; i < len; i++) {
		if (file[i-1] == '*' && file[i] == '/')
			break;
	}
	return i;
}

/* FIXME: Handle .s files differently (eg. # starts comments) --RR */
static int parse_file(const char *fname, struct md4_ctx *md)
{
	char *file;
	unsigned long i, len;

	file = grab_file(fname, &len);
	if (!file)
		return 0;

	for (i = 0; i < len; i++) {
		/* Collapse and ignore \ and CR. */
		if (file[i] == '\\' && (i+1 < len) && file[i+1] == '\n') {
			i++;
			continue;
		}

		/* Ignore whitespace */
		if (isspace(file[i]))
			continue;

		/* Handle strings as whole units */
		if (file[i] == '"') {
			i += parse_string(file+i, len - i, md);
			continue;
		}

		/* Comments: ignore */
		if (file[i] == '/' && file[i+1] == '*') {
			i += parse_comment(file+i, len - i);
			continue;
		}

		add_char(file[i], md);
	}
	release_file(file, len);
	return 1;
}

/* We have dir/file.o.  Open dir/.file.o.cmd, look for deps_ line to
 * figure out source file. */
static int parse_source_files(const char *objfile, struct md4_ctx *md)
{
	char *cmd, *file, *p, *end;
	const char *base;
	unsigned long flen;
	int dirlen, ret = 0;

	cmd = malloc(strlen(objfile) + sizeof("..cmd"));

	base = strrchr(objfile, '/');
	if (base) {
		base++;
		dirlen = base - objfile;
		sprintf(cmd, "%.*s.%s.cmd", dirlen, objfile, base);
	} else {
		dirlen = 0;
		sprintf(cmd, ".%s.cmd", objfile);
	}

	file = grab_file(cmd, &flen);
	if (!file) {
		fprintf(stderr, "Warning: could not find %s for %s\n",
			cmd, objfile);
		goto out;
	}

	/* There will be a line like so:
		deps_drivers/net/dummy.o := \
		  drivers/net/dummy.c \
		    $(wildcard include/config/net/fastroute.h) \
		  include/linux/config.h \
		    $(wildcard include/config/h.h) \
		  include/linux/module.h \

	   Sum all files in the same dir or subdirs.
	*/
	/* Strictly illegal: file is not nul terminated. */
	p = strstr(file, "\ndeps_");
	if (!p) {
		fprintf(stderr, "Warning: could not find deps_ line in %s\n",
			cmd);
		goto out_file;
	}
	p = strstr(p, ":=");
	if (!p) {
		fprintf(stderr, "Warning: could not find := line in %s\n",
			cmd);
		goto out_file;
	}
	p += strlen(":=");
	p += strspn(p, " \\\n");

	end = strstr(p, "\n\n");
	if (!end) {
		fprintf(stderr, "Warning: could not find end line in %s\n",
			cmd);
		goto out_file;
	}

	while (p < end) {
		unsigned int len;

		len = strcspn(p, " \\\n");
		if (memcmp(objfile, p, dirlen) == 0) {
			char source[len + 1];

			memcpy(source, p, len);
			source[len] = '\0';
			printf("parsing %s\n", source);
			if (!parse_file(source, md)) {
				fprintf(stderr,
					"Warning: could not open %s: %s\n",
					source, strerror(errno));
				goto out_file;
			}
		}
		p += len;
		p += strspn(p, " \\\n");
	}

	/* Everyone parsed OK */
	ret = 1;
out_file:
	release_file(file, flen);
out:
	free(cmd);
	return ret;
}

static int get_version(const char *modname, char sum[])
{
	void *file;
	unsigned long len;
	int ret = 0;
	struct md4_ctx md;
	char *sources, *end, *fname;
	const char *basename;
	char filelist[sizeof(".tmp_versions/%s.mod") + strlen(modname)];

	/* Source files for module are in .tmp_versions/modname.mod,
	   after the first line. */
	if (strrchr(modname, '/'))
		basename = strrchr(modname, '/') + 1;
	else
		basename = modname;
	sprintf(filelist, ".tmp_versions/%s", basename);
	/* Truncate .o, add .mod */
	strcpy(filelist + strlen(filelist)-2, ".mod");

	file = grab_file(filelist, &len);
	if (!file) {
		fprintf(stderr, "Warning: could not find versions for %s\n",
			filelist);
		return 0;
	}

	sources = strchr(file, '\n');
	if (!sources) {
		fprintf(stderr, "Warning: malformed versions file for %s\n",
			modname);
		goto release;
	}

	sources++;
	end = strchr(sources, '\n');
	if (!end) {
		fprintf(stderr, "Warning: bad ending versions file for %s\n",
			modname);
		goto release;
	}
	*end = '\0';

	md4_init(&md);
	for (fname = strtok(sources, " "); fname; fname = strtok(NULL, " ")) {
		if (!parse_source_files(fname, &md))
			goto release;
	}

	/* sum is of form \0<padding>. */
	md4_final_ascii(&md, sum, 1 + strlen(sum+1));
	ret = 1;
release:
	release_file(file, len);
	return ret;
}

static void write_version(const char *filename, const char *sum,
			  unsigned long offset)
{
	int fd;

	fd = open(filename, O_RDWR);
	if (fd < 0) {
		fprintf(stderr, "Warning: changing sum in %s failed: %s\n",
			filename, strerror(errno));
		return;
	}

	if (lseek(fd, offset, SEEK_SET) == (off_t)-1) {
		fprintf(stderr, "Warning: changing sum in %s:%lu failed: %s\n",
			filename, offset, strerror(errno));
		goto out;
	}

	if (write(fd, sum, strlen(sum)+1) != strlen(sum)+1) {
		fprintf(stderr, "Warning: writing sum in %s failed: %s\n",
			filename, strerror(errno));
		goto out;
	}
out:
	close(fd);
}

void strip_rcs_crap(char *version)
{
	unsigned int len, full_len;

	if (strncmp(version, "$Revision", strlen("$Revision")) != 0)
		return;

	/* Space for version string follows. */
	full_len = strlen(version) + strlen(version + strlen(version) + 1) + 2;

	/* Move string to start with version number: prefix will be
	 * $Revision$ or $Revision: */
	len = strlen("$Revision");
	if (version[len] == ':' || version[len] == '$')
		len++;
	while (isspace(version[len]))
		len++;
	memmove(version, version+len, full_len-len);
	full_len -= len;

	/* Preserve up to next whitespace. */
	len = 0;
	while (version[len] && !isspace(version[len]))
		len++;
	memmove(version + len, version + strlen(version),
		full_len - strlen(version));
}

/* If the modinfo contains a "version" value, then set this. */
void maybe_frob_version(const char *modfilename,
			void *modinfo,
			unsigned long modinfo_len,
			unsigned long modinfo_offset)
{
	char *version, *csum;

	version = get_modinfo(modinfo, modinfo_len, "version");
	if (!version)
		return;

	/* RCS $Revision gets stripped out. */
	strip_rcs_crap(version);

	/* Check against double sumversion */
	if (strchr(version, ' '))
		return;

	/* Version contains embedded NUL: second half has space for checksum */
	csum = version + strlen(version);
	*(csum++) = ' ';
	if (get_version(modfilename, csum))
		write_version(modfilename, version,
			      modinfo_offset + (version - (char *)modinfo));
}