/**********************************************************************
 *                        gostsum.c                                   *
 *             Copyright (c) 2005-2006 Cryptocom LTD                  *
 *         This file is distributed under the same license as OpenSSL *
 *                                                                    *
 *        Almost drop-in replacement for md5sum and sha1sum           *
 *          which computes GOST R 34.11-94 hashsum instead            *
 *                                                                    *
 **********************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <limits.h>
#include <fcntl.h>
#include <string.h>
#include "gosthash.h"
#define BUF_SIZE 262144
int hash_file(gost_hash_ctx * ctx, char *filename, char *sum, int mode);
int hash_stream(gost_hash_ctx * ctx, int fd, char *sum);
int get_line(FILE *f, char *hash, char *filename);
void help()
{
    fprintf(stderr, "gostsum [-bvt] [-c [file]]| [files]\n"
            "\t-c check message digests (default is generate)\n"
            "\t-v verbose, print file names when checking\n"
            "\t-b read files in binary mode\n"
            "\t-t use test GOST paramset (default is CryptoPro paramset)\n"
            "The input for -c should be the list of message digests and file names\n"
            "that is printed on stdout by this program when it generates digests.\n");
    exit(3);
}

#ifndef O_BINARY
# define O_BINARY 0
#endif

int main(int argc, char **argv)
{
    int c, i;
    int verbose = 0;
    int errors = 0;
    int open_mode = O_RDONLY;
    gost_subst_block *b = &GostR3411_94_CryptoProParamSet;
    FILE *check_file = NULL;
    gost_hash_ctx ctx;

    while ((c = getopt(argc, argv, "bc::tv")) != -1) {
        switch (c) {
        case 'v':
            verbose = 1;
            break;
        case 't':
            b = &GostR3411_94_TestParamSet;
            break;
        case 'b':
            open_mode |= O_BINARY;
            break;
        case 'c':
            if (optarg) {
                check_file = fopen(optarg, "r");
                if (!check_file) {
                    perror(optarg);
                    exit(2);
                }
            } else {
                check_file = stdin;
            }
            break;
        default:
            fprintf(stderr, "invalid option %c", optopt);
            help();
        }
    }
    init_gost_hash_ctx(&ctx, b);
    if (check_file) {
        char inhash[65], calcsum[65], filename[PATH_MAX];
        int failcount = 0, count = 0;;
        if (check_file == stdin && optind < argc) {
            check_file = fopen(argv[optind], "r");
            if (!check_file) {
                perror(argv[optind]);
                exit(2);
            }
        }
        while (get_line(check_file, inhash, filename)) {
            if (!hash_file(&ctx, filename, calcsum, open_mode)) {
                exit(2);
            }
            count++;
            if (!strncmp(calcsum, inhash, 65)) {
                if (verbose) {
                    fprintf(stderr, "%s\tOK\n", filename);
                }
            } else {
                if (verbose) {
                    fprintf(stderr, "%s\tFAILED\n", filename);
                } else {
                    fprintf(stderr,
                            "%s: GOST hash sum check failed for '%s'\n",
                            argv[0], filename);
                }
                failcount++;
            }
        }
        if (verbose && failcount) {
            fprintf(stderr,
                    "%s: %d of %d file(f) failed GOST hash sum check\n",
                    argv[0], failcount, count);
        }
        exit(failcount ? 1 : 0);
    }
    if (optind == argc) {
        char sum[65];
        if (!hash_stream(&ctx, fileno(stdin), sum)) {
            perror("stdin");
            exit(1);
        }
        printf("%s -\n", sum);
        exit(0);
    }
    for (i = optind; i < argc; i++) {
        char sum[65];
        if (!hash_file(&ctx, argv[i], sum, open_mode)) {
            errors++;
        } else {
            printf("%s %s\n", sum, argv[i]);
        }
    }
    exit(errors ? 1 : 0);
}

int hash_file(gost_hash_ctx * ctx, char *filename, char *sum, int mode)
{
    int fd;
    if ((fd = open(filename, mode)) < 0) {
        perror(filename);
        return 0;
    }
    if (!hash_stream(ctx, fd, sum)) {
        perror(filename);
        return 0;
    }
    close(fd);
    return 1;
}

int hash_stream(gost_hash_ctx * ctx, int fd, char *sum)
{
    unsigned char buffer[BUF_SIZE];
    ssize_t bytes;
    int i;
    start_hash(ctx);
    while ((bytes = read(fd, buffer, BUF_SIZE)) > 0) {
        hash_block(ctx, buffer, bytes);
    }
    if (bytes < 0) {
        return 0;
    }
    finish_hash(ctx, buffer);
    for (i = 0; i < 32; i++) {
        sprintf(sum + 2 * i, "%02x", buffer[31 - i]);
    }
    return 1;
}

int get_line(FILE *f, char *hash, char *filename)
{
    int i;
    if (fread(hash, 1, 64, f) < 64)
        return 0;
    hash[64] = 0;
    for (i = 0; i < 64; i++) {
        if (hash[i] < '0' || (hash[i] > '9' && hash[i] < 'A')
            || (hash[i] > 'F' && hash[i] < 'a') || hash[i] > 'f') {
            fprintf(stderr, "Not a hash value '%s'\n", hash);
            return 0;
        }
    }
    if (fgetc(f) != ' ') {
        fprintf(stderr, "Malformed input line\n");
        return 0;
    }
    i = strlen(fgets(filename, PATH_MAX, f));
    while (filename[--i] == '\n' || filename[i] == '\r')
        filename[i] = 0;
    return 1;
}