/*
 * 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.
 * Modified Sept 1993 by Peter Simons to compile on the Amiga.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "md5.h"
#include "getopt.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

#define USAGE "usage: md5sum [-bv] [-c [file]] | [file...]\n"           \
        "Generates or checks MD5 Message Digests\n"                     \
        "    -c  check message digests (default is generate)\n"         \
        "    -v  verbose, print file names when checking\n"             \
        "    -b  read files in binary mode\n"                           \
        "The input for -c should be the list of message digests and "   \
        "file names\nthat is printed on stdout by this program "        \
        "when it generates digests.\n"


extern char *optarg;
extern int optind;

void usage(void);
void print_digest(unsigned char *);
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);
        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;
}