piler/src/digest.c

/*
 * digest.c, SJ
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <syslog.h>
#include <piler.h>
#include <openssl/evp.h>


int make_body_digest(struct session_data *sdata, struct __config *cfg){
   int i=0, n, fd, hdr_len=0, offset=3;
   char *body=NULL;
   unsigned char buf[MAXBUFSIZE], md[DIGEST_LENGTH];
   SHA256_CTX context;

   //if(cfg->verbosity >= _LOG_DEBUG) syslog(LOG_PRIORITY, "%s: digesting", sdata->ttmpfile);

   memset(sdata->bodydigest, 0, 2*DIGEST_LENGTH+1);
   SHA256_Init(&context);

   fd = open(sdata->ttmpfile, O_RDONLY);
   if(fd == -1) return -1;

   while((n = read(fd, buf, MAXBUFSIZE)) > 0){
      body = (char *)&buf[0];

      if(i == 0){

         hdr_len = searchStringInBuffer(body, MAXBUFSIZE, "\n\r\n", 3);
         if(hdr_len == 0){
            searchStringInBuffer(body, 2*MAXBUFSIZE+1, "\n\n", 2);
            offset = 2;
         }

         if(hdr_len > 0){
            hdr_len += offset;

            sdata->hdr_len = hdr_len;

            body += hdr_len;
            n -= hdr_len;

            if(cfg->verbosity >= _LOG_DEBUG) syslog(LOG_PRIORITY, "%s: hdr_len: %d, offset: %d", sdata->ttmpfile, hdr_len, offset);
         }
      }


      SHA256_Update(&context, body, n);

      i++;
   }

   close(fd);

   SHA256_Final(md, &context);

   for(i=0;i<DIGEST_LENGTH;i++)
      snprintf(sdata->bodydigest + i*2, 2*DIGEST_LENGTH, "%02x", md[i]);

   return 0;
}


void digest_file(char *filename, char *digest){
   int fd, i, n;
   unsigned char buf[MAXBUFSIZE], md[DIGEST_LENGTH];
   SHA256_CTX context;

   memset(digest, 0, 2*DIGEST_LENGTH+1);

   fd = open(filename, O_RDONLY);
   if(fd == -1) return;

   SHA256_Init(&context);

   while((n = read(fd, buf, MAXBUFSIZE)) > 0){
      SHA256_Update(&context, buf, n);
   }

   close(fd);

   SHA256_Final(md, &context);

   for(i=0;i<DIGEST_LENGTH;i++)
      snprintf(digest + i*2, 2*DIGEST_LENGTH, "%02x", md[i]);

}