/*      $OpenBSD: helper.c,v 1.19 2026/03/10 16:20:57 deraadt Exp $ */

/*
 * Copyright (c) 2000 Poul-Henning Kamp <phk@FreeBSD.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

/*
 * If we meet some day, and you think this stuff is worth it, you
 * can buy me a beer in return. Poul-Henning Kamp
 */

#include <sys/types.h>
#include <sys/stat.h>

#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>

#include <hashinc>

#define MINIMUM(a, b)   (((a) < (b)) ? (a) : (b))

char *
HASHEnd(HASH_CTX *ctx, char *buf)
{
        int i;
        u_int8_t digest[HASH_DIGEST_LENGTH];
        static const char hex[] = "0123456789abcdef";

        if (buf == NULL && (buf = malloc(HASH_DIGEST_STRING_LENGTH)) == NULL)
                return (NULL);

        HASHFinal(digest, ctx);
        for (i = 0; i < HASH_DIGEST_LENGTH; i++) {
                buf[i + i] = hex[digest[i] >> 4];
                buf[i + i + 1] = hex[digest[i] & 0x0f];
        }
        buf[i + i] = '\0';
        explicit_bzero(digest, sizeof(digest));
        return (buf);
}
DEF_WEAK(HASHEnd);

char *
HASHFileChunk(const char *filename, char *buf, off_t off, off_t len)
{
        struct stat sb;
        u_char buffer[BUFSIZ];
        HASH_CTX ctx;
        int fd, save_errno;
        ssize_t nr;

        HASHInit(&ctx);

        if ((fd = open(filename, O_RDONLY|O_CLOEXEC)) == -1)
                return (NULL);
        if (len == 0) {
                if (fstat(fd, &sb) == -1) {
                        save_errno = errno;
                        close(fd);
                        errno = save_errno;
                        return (NULL);
                }
                len = sb.st_size;
        }
        if (off > 0 && lseek(fd, off, SEEK_SET) == -1) {
                save_errno = errno;
                close(fd);
                errno = save_errno;
                return (NULL);
        }

        while ((nr = read(fd, buffer, MINIMUM(sizeof(buffer), len))) > 0) {
                HASHUpdate(&ctx, buffer, nr);
                if (len > 0 && (len -= nr) == 0)
                        break;
        }

        save_errno = errno;
        close(fd);
        errno = save_errno;
        return (nr == -1 ? NULL : HASHEnd(&ctx, buf));
}
DEF_WEAK(HASHFileChunk);

char *
HASHFile(const char *filename, char *buf)
{
        return (HASHFileChunk(filename, buf, 0, 0));
}
DEF_WEAK(HASHFile);

char *
HASHData(const u_char *data, size_t len, char *buf)
{
        HASH_CTX ctx;

        HASHInit(&ctx);
        HASHUpdate(&ctx, data, len);
        return (HASHEnd(&ctx, buf));
}
DEF_WEAK(HASHData);