Документация по криптоалгоритмам / The MD5 Algorithm Specification and Source (eng - txt) / md5sum

/*

 * md5sum.c	- Generate/check MD5 Message Digests

 *

 * Compile and link with md5.c.  If you don't have getopt() in your library

 * also include getopt.c.  For MSDOS you can also link with the wildcard

 * initialization function (wildargs.obj for Turbo C and setargv.obj for MSC)

 * so that you can use wildcards on the commandline.

 *

 * Written March 1993 by Branko Lankester

 * Modified June 1993 by Colin Plumb for altered md5.c.

 */

#include <stdio.h>

#include <string.h>

#include "md5.h"



#ifdef UNIX

#define	FOPRTXT	"r"

#define	FOPRBIN	"r"

#else

#ifdef VMS

#define	FOPRTXT	"r","ctx=stm"

#define	FOPRBIN	"rb","ctx=stm"

#else

#define	FOPRTXT	"r"

#define	FOPRBIN	"rb"

#endif

#endif



extern char *optarg;

extern int optind;



void usage();

void print_digest();

int mdfile(FILE *fp, unsigned char *digest);

int do_check(FILE *chkf);



char *progname;

int verbose = 0;

int bin_mode = 0;



void

main(int argc, char **argv)

{

	int opt, rc = 0;

	int check = 0;

	FILE *fp;

	unsigned char digest[16];



	progname = *argv;

	while ((opt = getopt(argc, argv, "cbvp:h")) != EOF) {

		switch (opt) {

			case 'c': check = 1; break;

			case 'v': verbose = 1; break;

			case 'b': bin_mode = 1; break;

			default: usage();

		}

	}

	argc -= optind;

	argv += optind;

	if (check) {

		switch (argc) {

			case 0: fp = stdin; break;

			case 1: if ((fp = fopen(*argv, FOPRTXT)) == NULL) {

					perror(*argv);

					exit(2);

				}

				break;

			default: usage();

		}

		exit(do_check(fp));

	}

	if (argc == 0) {

		if (mdfile(stdin, digest)) {

			fprintf(stderr, "%s: read error on stdin\n", progname);

			exit(2);

		}

		print_digest(digest);

		printf("\n");

		exit(0);

	}

	for ( ; argc > 0; --argc, ++argv) {

		if (bin_mode)

			fp = fopen(*argv, FOPRBIN);

		else

			fp = fopen(*argv, FOPRTXT);

		if (fp == NULL) {

			perror(*argv);

			rc = 2;

			continue;

		}

		if (mdfile(fp, digest)) {

			fprintf(stderr, "%s: error reading %s\n", progname, *argv);

			rc = 2;

		} else {

			print_digest(digest);

			printf(" %c%s\n", bin_mode ? '*' : ' ', *argv);

		}

		fclose(fp);

	}

	exit(rc);

}



void

usage()

{

	fprintf(stderr, "usage: md5sum [-bv] [-c [file]] | [file...]\n");

	fprintf(stderr, "Generates or checks MD5 Message Digests\n");

	fprintf(stderr, "    -c  check message digests (default is generate)\n");

	fprintf(stderr, "    -v  verbose, print file names when checking\n");

	fprintf(stderr, "    -b  read files in binary mode\n");

	fprintf(stderr, "The input for -c should be the list of message digests and file names\n");

	fprintf(stderr, "that is printed on stdout by this program when it generates digests.\n");

	exit(2);

}



int

mdfile(FILE *fp, unsigned char *digest)

{

	unsigned char buf[1024];

	MD5_CTX ctx;

	int n;



	MD5Init(&ctx);

	while ((n = fread(buf, 1, sizeof(buf), fp)) > 0)

		MD5Update(&ctx, buf, n);

	MD5Final(digest, &ctx);

	if (ferror(fp))

		return -1;

	return 0;

}



void

print_digest(unsigned char *p)

{

	int i;



	for (i = 0; i < 16; ++i)

		printf("%02x", *p++);

}



int

hex_digit(int c)

{

	if (c >= '0' && c <= '9')

		return c - '0';

	if (c >= 'a' && c <= 'f')

		return c - 'a' + 10;

	return -1;

}



int

get_md5_line(FILE *fp, unsigned char *digest, char *file)

{

	char buf[1024];

	int i, d1, d2, rc;

	char *p = buf;



	if (fgets(buf, sizeof(buf), fp) == NULL)

		return -1;



	for (i = 0; i < 16; ++i) {

		if ((d1 = hex_digit(*p++)) == -1)

			return 0;

		if ((d2 = hex_digit(*p++)) == -1)

			return 0;

		*digest++ = d1*16 + d2;

	}

	if (*p++ != ' ')

		return 0;

	/*

	 * next char is an attribute char, space means text file

	 * if it's a '*' the file should be checked in binary mode.

	 */

	if (*p == ' ')

		rc = 1;

	else if (*p == '*')

		rc = 2;

	else {

		fprintf(stderr, "%s: unrecognized line: %s", progname, buf);

		return 0;

	}

	++p;

	i = strlen(p);

	if (i < 2 || i > 255)

		return 0;

	p[i-1] = '\0';

	strcpy(file, p);

	return rc;

}



int

do_check(FILE *chkf)

{

	int rc, ex = 0, failed = 0, checked = 0;

	unsigned char chk_digest[16], file_digest[16];

	char filename[256];

	FILE *fp;

	int flen = 14;



	while ((rc = get_md5_line(chkf, chk_digest, filename)) >= 0) {

		if (rc == 0)	/* not an md5 line */

			continue;

		if (verbose) {

			if (strlen(filename) > flen)

				flen = strlen(filename);

			fprintf(stderr, "%-*s ", flen, filename);

		}

		if (bin_mode || rc == 2)

			fp = fopen(filename, FOPRBIN);

		else

			fp = fopen(filename, FOPRTXT);

		if (fp == NULL) {

			fprintf(stderr, "%s: can't open %s\n", progname, filename);

			ex = 2;

			continue;

		}

		if (mdfile(fp, file_digest)) {

			fprintf(stderr, "%s: error reading %s\n", progname, filename);

			ex = 2;

			fclose(fp);

			continue;

		}

		fclose(fp);

		if (memcmp(chk_digest, file_digest, 16) != 0) {

			if (verbose)

				fprintf(stderr, "FAILED\n");

			else

				fprintf(stderr, "%s: MD5 check failed for '%s'\n", progname, filename);

			++failed;

		} else if (verbose)

			fprintf(stderr, "OK\n");

		++checked;

	}

	if (verbose && failed)

		fprintf(stderr, "%s: %d of %d file(s) failed MD5 check\n", progname, failed, checked);

	if (!checked) {

		fprintf(stderr, "%s: no files checked\n", progname);

		return 3;

	}

	if (!ex && failed)

		ex = 1;

	return ex;

}