checktag.c

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#include "stralloc.h"
#include "scan.h"
#include "fmt.h"
#include "cookie.h"
#include "makehash.h"
#include "readclose.h"
#include "byte.h"
#include "errtxt.h"
#include "subscribe.h"
 
#define WHO "checktag"

 
static stralloc key = {0};
static char strnum[FMT_ULONG];
static char newcookie[COOKIE];
 
const char *checktag(const char *dir,           /* the db base dir */
                     unsigned long num,                   /* message number */
                     unsigned long listno,              /* bottom of range => slave */
                     const char *action,
                     const char *seed,                    /* cookie base */
                     const char *hash)                    /* cookie */
{
  if (!seed) return (char *) 0;               /* no data - accept */
 
  strnum[fmt_ulong(strnum,num)] = '\0'; /* message nr ->string*/
 
  switch (openreadclose("key",&key,32)) {
    case -1: return ERR_READ_KEY;
    case  0: return ERR_NOEXIST_KEY;
  }
 
  cookie(newcookie,key.s,key.len,strnum,seed,action);
  if (byte_diff(hash,COOKIE,newcookie)) return "";
  else return (char *) 0;
}