scripts/mod/sumversion.c - LeafOS-Devices/android_kernel_samsung_exynos9820 - Gitiles

 #include <netinet/in.h>
 #ifdef __sun__
 #include <inttypes.h>
 #else
 #include <stdint.h>
 #endif
 #include <ctype.h>
 #include <errno.h>
 #include <string.h>
 #include "modpost.h"

 /*
  * 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, *line, *dir;
 	const char *base;
 	unsigned long flen, pos = 0;
 	int dirlen, ret = 0, check_files = 0;

 	cmd = NOFAIL(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);
 	}
 	dir = NOFAIL(malloc(dirlen + 1));
 	strncpy(dir, objfile, dirlen);
 	dir[dirlen] = '\0';

 	file = grab_file(cmd, &flen);
 	if (!file) {
 		warn("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.
 	*/
 	while ((line = get_next_line(&pos, file, flen)) != NULL) {
 		char* p = line;
 		if (strncmp(line, "deps_", sizeof("deps_")-1) == 0) {
 			check_files = 1;
 			continue;
 		}
 		if (!check_files)
 			continue;

 		/* Continue until line does not end with '\' */
 		if ( *(p + strlen(p)-1) != '\\')
 			break;
 		/* Terminate line at first space, to get rid of final ' \' */
 		while (*p) {
                        if (isspace(*p)) {
 				*p = '\0';
 				break;
 			}
 			p++;
 		}

 		/* Check if this file is in same dir as objfile */
 		if ((strstr(line, dir)+strlen(dir)-1) == strrchr(line, '/')) {
 			if (!parse_file(line, md)) {
 				warn("could not open %s: %s\n",
 				     line, strerror(errno));
 				goto out_file;
 			}

 		}

 	}

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

 /* Calc and record src checksum. */
 void get_src_version(const char *modname, char sum[], unsigned sumlen)
 {
 	void *file;
 	unsigned long len;
 	struct md4_ctx md;
 	char *sources, *end, *fname;
 	const char *basename;
 	char filelist[strlen(getenv("MODVERDIR")) + strlen("/") +
 		      strlen(modname) - strlen(".o") + strlen(".mod") + 1 ];

 	/* 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, "%s/%.*s.mod", getenv("MODVERDIR"),
 		(int) strlen(basename) - 2, basename);

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

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

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

 	md4_init(&md);
 	while ((fname = strsep(&sources, " ")) != NULL) {
 		if (!*fname)
 			continue;
 		if (!parse_source_files(fname, &md))
 			goto release;
 	}

 	md4_final_ascii(&md, sum, sumlen);
 release:
 	release_file(file, len);
 }

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

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

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

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

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

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

 	/* 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));
 	return 1;
 }

 /* Clean up RCS-style version numbers. */
 void maybe_frob_rcs_version(const char *modfilename,
 			    char *version,
 			    void *modinfo,
 			    unsigned long version_offset)
 {
 	if (strip_rcs_crap(version))
 		write_version(modfilename, version, version_offset);
 }
	#include <netinet/in.h>
	#ifdef __sun__
	#include <inttypes.h>
	#else
	#include <stdint.h>
	#endif
	#include <ctype.h>
	#include <errno.h>
	#include <string.h>
	#include "modpost.h"

	/*
	* 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, line, dir;
	const char *base;
	unsigned long flen, pos = 0;
	int dirlen, ret = 0, check_files = 0;

	cmd = NOFAIL(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);
	}
	dir = NOFAIL(malloc(dirlen + 1));
	strncpy(dir, objfile, dirlen);
	dir[dirlen] = '\0';

	file = grab_file(cmd, &flen);
	if (!file) {
	warn("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.
	*/
	while ((line = get_next_line(&pos, file, flen)) != NULL) {
	char* p = line;
	if (strncmp(line, "deps_", sizeof("deps_")-1) == 0) {
	check_files = 1;
	continue;
	}
	if (!check_files)
	continue;

	/* Continue until line does not end with '\' */
	if ( *(p + strlen(p)-1) != '\\')
	break;
	/* Terminate line at first space, to get rid of final ' \' */
	while (*p) {
	if (isspace(*p)) {
	*p = '\0';
	break;
	}
	p++;
	}

	/* Check if this file is in same dir as objfile */
	if ((strstr(line, dir)+strlen(dir)-1) == strrchr(line, '/')) {
	if (!parse_file(line, md)) {
	warn("could not open %s: %s\n",
	line, strerror(errno));
	goto out_file;
	}

	}

	}

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

	/* Calc and record src checksum. */
	void get_src_version(const char *modname, char sum[], unsigned sumlen)
	{
	void *file;
	unsigned long len;
	struct md4_ctx md;
	char sources, end, *fname;
	const char *basename;
	char filelist[strlen(getenv("MODVERDIR")) + strlen("/") +
	strlen(modname) - strlen(".o") + strlen(".mod") + 1 ];

	/* 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, "%s/%.*s.mod", getenv("MODVERDIR"),
	(int) strlen(basename) - 2, basename);

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

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

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

	md4_init(&md);
	while ((fname = strsep(&sources, " ")) != NULL) {
	if (!*fname)
	continue;
	if (!parse_source_files(fname, &md))
	goto release;
	}

	md4_final_ascii(&md, sum, sumlen);
	release:
	release_file(file, len);
	}

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

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

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

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

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

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

	/* 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));
	return 1;
	}

	/* Clean up RCS-style version numbers. */
	void maybe_frob_rcs_version(const char *modfilename,
	char *version,
	void *modinfo,
	unsigned long version_offset)
	{
	if (strip_rcs_crap(version))
	write_version(modfilename, version, version_offset);
	}