checktag.c

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#include "slurp.h"
#include "byte.h"
#include "stralloc.h"
#include "scan.h"
#include "fmt.h"
#include "cookie.h"
#include "makehash.h"
#include "subscribe.h"
#include <mysql/mysql.h>
#include "errtxt.h"
#include "logmsg.h"
 
#define WHO "checktag"

 
extern MYSQL *mysql;
 
static stralloc key = {0};
static stralloc line = {0};
static stralloc quoted = {0};
static char strnum[FMT_ULONG];
static char newcookie[COOKIE];

 
const char *checktag(const char *dir,unsigned long num,unsigned long listno,
                     const char *action,const char *seed, const char *hash)
{
  MYSQL_RES *result;
  MYSQL_ROW row;
  const char *table = (char *) 0;
  const char *r;
 
  if ((r = opensql(dir,&table))) {
    if (*r) return r;
    if (!seed) return (char *) 0;                           /* no data - accept */
 
    strnum[fmt_ulong(strnum,num)] = '\0';                   /* message nr ->string*/
 
    switch(slurp("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;
 
  } else {
 
/* SELECT msgnum FROM table_cookie WHERE msgnum=num and cookie='hash' */
/* succeeds only is everything correct. 'hash' is quoted since it is  */
/*  potentially hostile. */
 
    if (listno) {                                          /* only for slaves */
      if (!stralloc_copys(&line,"SELECT listno FROM ")) return ERR_NOMEM;
      if (!stralloc_cats(&line,table)) return ERR_NOMEM;
      if (!stralloc_cats(&line,"_mlog WHERE listno=")) return ERR_NOMEM;
      if (!stralloc_catb(&line,strnum,fmt_ulong(strnum,listno))) return ERR_NOMEM;
      if (!stralloc_cats(&line," AND msgnum=")) return ERR_NOMEM;
      if (!stralloc_catb(&line,strnum,fmt_ulong(strnum,num))) return ERR_NOMEM;
      if (!stralloc_cats(&line," AND done > 3")) return ERR_NOMEM;
      if (mysql_real_query(mysql,line.s,line.len) != 0) 
        return mysql_error(mysql);                          /* query */
 
      if (!(result = mysql_use_result(mysql)))        
        return mysql_error(mysql);                         /* use result */
 
      return mysql_error(mysql);
 
      if ((row = mysql_fetch_row(result)))
        return "";                                         /* already done */
      else                                                 /* no result */
        if (!mysql_eof(result))
          return mysql_error(mysql);
 
      mysql_free_result(result);                          /* free res */
    }
 
    if (!stralloc_copys(&line,"SELECT msgnum FROM ")) return ERR_NOMEM;
    if (!stralloc_cats(&line,table)) return ERR_NOMEM;
    if (!stralloc_cats(&line,"_cookie WHERE msgnum=")) return ERR_NOMEM;
    if (!stralloc_catb(&line,strnum,fmt_ulong(strnum,num))) return ERR_NOMEM;
    if (!stralloc_cats(&line," and cookie='")) return ERR_NOMEM;
    if (!stralloc_ready(&quoted,COOKIE * 2 + 1)) return ERR_NOMEM;
    quoted.len = mysql_escape_string(quoted.s,hash,COOKIE);
    if (!stralloc_cat(&line,&quoted)) return ERR_NOMEM;
    if (!stralloc_cats(&line,"'")) return ERR_NOMEM;
 
    if (mysql_real_query(mysql,line.s,line.len) != 0)      /* select */
      return mysql_error(mysql);
 
    if (!(result = mysql_use_result(mysql))) 
      return mysql_error(mysql);
 
    if (!mysql_fetch_row(result)) {
      if (!mysql_eof(result))                              /* some error occurred */
        return mysql_error(mysql);
      mysql_free_result(result);                           /* eof => query ok, but null result*/
      return "";                                           /* not parent => perm error */
    }
    mysql_free_result(result);                             /* success! cookie matches */
    if (listno)
      loginfo(dir,num,listno,0L,3);                        /* non-ess mysql logging */
    return (char *)0;
  }
}