/* vi: set sw=4 ts=4: */
/*
 *  Copyright (C) 2003 Glenn L. McGrath
 *  Copyright (C) 2003-2004 Erik Andersen
 *
 * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
 */

#include "libbb.h"

typedef enum {
        /* 4th letter of applet_name is... */
        HASH_MD5 = 's', /* "md5>s<um" */
        HASH_SHA1 = '1',
        HASH_SHA256 = '2',
        HASH_SHA512 = '5',
} hash_algo_t;

#define FLAG_SILENT     1
#define FLAG_CHECK      2
#define FLAG_WARN       4

/* This might be useful elsewhere */
static unsigned char *hash_bin_to_hex(unsigned char *hash_value,
                                unsigned hash_length)
{
        /* xzalloc zero-terminates */
        char *hex_value = xzalloc((hash_length * 2) + 1);
        bin2hex(hex_value, (char*)hash_value, hash_length);
        return (unsigned char *)hex_value;
}

static uint8_t *hash_file(const char *filename /*, hash_algo_t hash_algo*/)
{
        int src_fd, hash_len, count;
        union _ctx_ {
                sha512_ctx_t sha512;
                sha256_ctx_t sha256;
                sha1_ctx_t sha1;
                md5_ctx_t md5;
        } context;
        uint8_t *hash_value = NULL;
        RESERVE_CONFIG_UBUFFER(in_buf, 4096);
        void FAST_FUNC (*update)(const void*, size_t, void*);
        void FAST_FUNC (*final)(void*, void*);
        hash_algo_t hash_algo = applet_name[3];

        src_fd = open_or_warn_stdin(filename);
        if (src_fd < 0) {
                return NULL;
        }

        /* figure specific hash algorithims */
        if (ENABLE_MD5SUM && hash_algo == HASH_MD5) {
                md5_begin(&context.md5);
                update = (void*)md5_hash;
                final = (void*)md5_end;
                hash_len = 16;
        } else if (ENABLE_SHA1SUM && hash_algo == HASH_SHA1) {
                sha1_begin(&context.sha1);
                update = (void*)sha1_hash;
                final = (void*)sha1_end;
                hash_len = 20;
        } else if (ENABLE_SHA256SUM && hash_algo == HASH_SHA256) {
                sha256_begin(&context.sha256);
                update = (void*)sha256_hash;
                final = (void*)sha256_end;
                hash_len = 32;
        } else if (ENABLE_SHA512SUM && hash_algo == HASH_SHA512) {
                sha512_begin(&context.sha512);
                update = (void*)sha512_hash;
                final = (void*)sha512_end;
                hash_len = 64;
        } else {
                bb_error_msg_and_die("algorithm not supported");
        }

        while (0 < (count = safe_read(src_fd, in_buf, 4096))) {
                update(in_buf, count, &context);
        }

        if (count == 0) {
                final(in_buf, &context);
                hash_value = hash_bin_to_hex(in_buf, hash_len);
        }

        RELEASE_CONFIG_BUFFER(in_buf);

        if (src_fd != STDIN_FILENO) {
                close(src_fd);
        }

        return hash_value;
}

int md5_sha1_sum_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int md5_sha1_sum_main(int argc UNUSED_PARAM, char **argv)
{
        int return_value = EXIT_SUCCESS;
        uint8_t *hash_value;
        unsigned flags;
        /*hash_algo_t hash_algo = applet_name[3];*/

        if (ENABLE_FEATURE_MD5_SHA1_SUM_CHECK)
                flags = getopt32(argv, "scw");
        else optind = 1;
        argv += optind;
        //argc -= optind;
        if (!*argv)
                *--argv = (char*)"-";

        if (ENABLE_FEATURE_MD5_SHA1_SUM_CHECK && !(flags & FLAG_CHECK)) {
                if (flags & FLAG_SILENT) {
                        bb_error_msg_and_die
                                ("-%c is meaningful only when verifying checksums", 's');
                } else if (flags & FLAG_WARN) {
                        bb_error_msg_and_die
                                ("-%c is meaningful only when verifying checksums", 'w');
                }
        }

        if (ENABLE_FEATURE_MD5_SHA1_SUM_CHECK && (flags & FLAG_CHECK)) {
                FILE *pre_computed_stream;
                int count_total = 0;
                int count_failed = 0;
                char *line;

                if (argv[1]) {
                        bb_error_msg_and_die
                                ("only one argument may be specified when using -c");
                }

                pre_computed_stream = xfopen_stdin(argv[0]);

                while ((line = xmalloc_fgetline(pre_computed_stream)) != NULL) {
                        char *filename_ptr;

                        count_total++;
                        filename_ptr = strstr(line, "  ");
                        /* handle format for binary checksums */
                        if (filename_ptr == NULL) {
                                filename_ptr = strstr(line, " *");
                        }
                        if (filename_ptr == NULL) {
                                if (flags & FLAG_WARN) {
                                        bb_error_msg("invalid format");
                                }
                                count_failed++;
                                return_value = EXIT_FAILURE;
                                free(line);
                                continue;
                        }
                        *filename_ptr = '\0';
                        filename_ptr += 2;

                        hash_value = hash_file(filename_ptr /*, hash_algo*/);

                        if (hash_value && (strcmp((char*)hash_value, line) == 0)) {
                                if (!(flags & FLAG_SILENT))
                                        printf("%s: OK\n", filename_ptr);
                        } else {
                                if (!(flags & FLAG_SILENT))
                                        printf("%s: FAILED\n", filename_ptr);
                                count_failed++;
                                return_value = EXIT_FAILURE;
                        }
                        /* possible free(NULL) */
                        free(hash_value);
                        free(line);
                }
                if (count_failed && !(flags & FLAG_SILENT)) {
                        bb_error_msg("WARNING: %d of %d computed checksums did NOT match",
                                                 count_failed, count_total);
                }
                /*
                if (fclose_if_not_stdin(pre_computed_stream) == EOF) {
                        bb_perror_msg_and_die("cannot close file %s", file_ptr);
                }
                */
        } else {
                do {
                        hash_value = hash_file(*argv/*, hash_algo*/);
                        if (hash_value == NULL) {
                                return_value = EXIT_FAILURE;
                        } else {
                                printf("%s  %s\n", hash_value, *argv);
                                free(hash_value);
                        }
                } while (*++argv);
        }
        return return_value;
}