I am using a program that send http request on multiple threads (simplest way we can do). The programs seems to run nice, and always randomly segfaults on curl calls.

Take a look at this gdb debug :

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 13326 (LWP 2770)]
0x400bb9a6 in addbyter (output=110, data=0xbd1feeec) at mprintf.c:989
989 mprintf.c: No such file or directory.
        in mprintf.c
(gdb) where
#0 0x400bb9a6 in addbyter (output=110, data=0xbd1feeec) at mprintf.c:989
#1 0x400bab16 in dprintf_formatf (data=0xbd1feeec,
    stream=0x400bb990 <addbyter>, format=0x400cd248 "name lookup timed out",
    ap_save=0xbd1fef44) at mprintf.c:645
#2 0x400bba0f in curl_mvsnprintf (
    buffer=0x8188450 <Address 0x8188450 out of bounds>, maxlength=16384,
    format=0x400cd248 "name lookup timed out", ap_save=0xbd1fef44)
    at mprintf.c:1007
#3 0x400af241 in Curl_failf (data=0x8188180,
    fmt=0x400cd248 "name lookup timed out") at sendf.c:160
#4 0x400a870f in Curl_resolv (conn=0x402437af, hostname=0xbd1ff50c "",
    port=0, entry=0x0) at hostip.c:385

What is wrong there ?

Here is my curl code for request :

//******* WEBPAGE Struct
typedef struct{
    size_t pagesize;
    char *htmlcode;
}WEBPAGE;

//********************************************************************
// gets downloaded data
size_t _refGetPageFunc(void *ptr, size_t size, size_t nmemb, void *buffer)
{
     size_t realsize = size * nmemb;
     WEBPAGE *mem = (WEBPAGE *)buffer;
     int psize = strlen(ptr);

     mem->htmlcode = realloc(mem->htmlcode, mem->pagesize + realsize + 1);
     if(mem->htmlcode)
     {
         memcpy(&(mem->htmlcode[mem->pagesize]), ptr, realsize);
         mem->pagesize += realsize;
         mem->htmlcode[mem->pagesize] = '\0';
    }
    else
         printf("[Curl]error: unallocated buffer\n");

    return realsize;
}

//********************************************************************
// Frees a WEBPAGE struture
void refFreeWebpage(WEBPAGE *data)
{
     curl_free(data->htmlcode);
     curl_free(data);
}

//********************************************************************
// Gets a web page's html code with parameters
// return value : the page text
char *refGetHTTPPage(char *pagename, long timeout)
{
     char errbuf[CURL_ERROR_SIZE+128];
     char *rcode;
     WEBPAGE *data;
     CURLcode res;
     CURL *curl = curl_easy_init();
     char ua[] = "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1)";

     if(pagename == NULL)
     {
          printf("[HTTP] nom de page manquant. Certainement un bug\n");
          return NULL;
     }

     data = malloc(sizeof(*data));
     data->htmlcode = malloc(sizeof(*(data->htmlcode)));
     data->pagesize = 0;

     if(curl)
     {
          curl_easy_setopt(curl, CURLOPT_URL, pagename);
          curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, _refGetPageFunc);
          curl_easy_setopt(curl, CURLOPT_WRITEDATA, data);
          curl_easy_setopt(curl, CURLOPT_TIMEOUT, timeout);
          curl_easy_setopt(curl, CURLOPT_ERRORBUFFER, &errbuf);
          curl_easy_setopt(curl, CURLOPT_USERAGENT, ua);
          curl_easy_setopt(curl, CURLOPT_DNS_CACHE_TIMEOUT, 60);
   
          res = curl_easy_perform(curl);
          curl_easy_cleanup(curl);

          if(res != CURLE_OK)
          {
               printf("[HTTP]: URL [%s] failed\n[HTTP]: %s (code %i)\n", pagename, errbuf, res);
               refFreeWebpage(data);
               return NULL;
          }
     }
     else
     {
          printf("[HTTP] cURL n'a pas été initialisee\n");
          refFreeWebpage(data);
          return NULL;
     }

     rcode = strdup(data->htmlcode);
     refFreeWebpage(data);

     return rcode;
}

cya
Received on 2005-04-08