const char *zRef = P("referer");
  if( zRef==0 ){
    zRef = P("HTTP_REFERER");
    if( zRef==0 ) zRef = zDefault;
  }
  return zRef;
}

/*
** Return true if the current request appears to be safe from a
** Cross-Site Request Forgery (CSRF) attack.  Conditions that must
** be met:
**
**    *   The HTTP_REFERER must have the same origin
**    *   The REQUEST_METHOD must be POST - or requirePost==0
*/
int cgi_csrf_safe(int requirePost){
  const char *zRef = P("HTTP_REFERER");
  int nBase;
  if( zRef==0 ) return 0;
  if( requirePost ){
    const char *zMethod = P("REQUEST_METHOD");
    if( zMethod==0 ) return 0;
    if( strcmp(zMethod,"POST")!=0 ) return 0;
  }
  nBase = (int)strlen(g.zBaseURL);
  if( strncmp(g.zBaseURL,zRef,nBase)!=0 ) return 0;
  if( zRef[nBase]!=0 && zRef[nBase]!='/' ) return 0;
  return 1;
}

/*
** Information about all query parameters and cookies are stored
** in these variables.
*/
static int nAllocQP = 0; /* Space allocated for aParamQP[] */
static int nUsedQP = 0;  /* Space actually used in aParamQP[] */

    return;
  }

  /* If we have all the necessary information, write the new or
  ** modified user record.  After writing the user record, redirect
  ** to the page that displays a list of users.
  */
  doWrite = cgi_all("login","info","pw") && !higherUser && cgi_csrf_safe(1);
  if( doWrite ){
    char c;
    char zCap[50], zNm[4];
    zNm[0] = 'a';
    zNm[2] = 0;
    for(i=0, c='a'; c<='z'; c++){
      zNm[1] = c;

void setup_adunit(void){
  login_check_credentials();
  if( !g.perm.Setup ){
    login_needed(0);
    return;
  }
  db_begin_transaction();
  if( P("clear")!=0 && cgi_csrf_safe(1) ){
    db_multi_exec("DELETE FROM config WHERE name GLOB 'adunit*'");
    cgi_replace_parameter("adunit","");
  }

  style_header("Edit Ad Unit");
  @ <form action="%s(g.zTop)/setup_adunit" method="post"><div>
  login_insert_csrf_secret();

  }
  login_check_credentials();
  if( !g.perm.Setup ){
    login_needed(0);
    return;
  }
  db_begin_transaction();
  if( !cgi_csrf_safe(1) ){
    /* Allow no state changes if not safe from CSRF */
  }else if( P("setlogo")!=0 && zLogoMime && zLogoMime[0] && szLogoImg>0 ){
    Blob img;
    Stmt ins;
    blob_init(&img, aLogoImg, szLogoImg);
    db_prepare(&ins,
        "REPLACE INTO config(name,value,mtime)"
        " VALUES('logo-image',:bytes,now())"
    );

/*
** WEBPAGE: admin_sql
**
** Run raw SQL commands against the database file using the web interface.
** Requires Admin privileges.
*/
void sql_page(void){
  const char *zQ;
  int go = P("go")!=0;
  login_check_credentials();
  if( !g.perm.Setup ){
    login_needed(0);
    return;
  }
  add_content_sql_commands(g.db);
  db_begin_transaction();
  zQ = cgi_csrf_safe(1) ? P("q") : 0;
  style_header("Raw SQL Commands");
  @ <p><b>Caution:</b> There are no restrictions on the SQL that can be
  @ run by this page.  You can do serious and irrepairable damage to the
  @ repository.  Proceed with extreme caution.</p>
  @
#if 0
  @ <p>Only the first statement in the entry box will be run.

*/
static void setup_update_url_alias(
  Blob *pSql,
  const char *zOldName,
  const char *zNewName,
  const char *zValue
){
  if( !cgi_csrf_safe(1) ) return;
  if( zNewName[0]==0 || zValue[0]==0 ){
    if( zOldName[0] ){
      blob_append_sql(pSql,
        "DELETE FROM config WHERE name='walias:%q';\n",
        zOldName);
    }
    return;

  }
  zCap[i] = 0;
  if( i>0 ){
    @ anonymous-adds = %s(zCap)<br />
  }
  @ g.zRepositoryName = %h(g.zRepositoryName)<br />
  @ load_average() = %f(load_average())<br />
  @ cgi_csrf_safe(0) = %d(cgi_csrf_safe(0))<br />
  @ <hr />
  P("HTTP_USER_AGENT");
  cgi_print_all(showAll);
  if( showAll && blob_size(&g.httpHeader)>0 ){
    @ <hr />
    @ <pre>
    @ %h(blob_str(&g.httpHeader))