glibc detected *** double free or corruption

[sreenu_daram]

Hi All ,
when I am writing an application using libcurl to send https request,

my error log showing this error : *** glibc detected *** double free or corruption (fasttop): 0x09511d40 ***

Give me any idea.


Regards,
Sreenu Daram.

hi This is the code :
<< SNIPPED DUE TO LACK OF CODE TAGS >>

[Dave_Sinkula]

Give me any idea.

Post your code.

[sreenu_daram]

Hi This is my code :
<< SNIPPED DUE TO STILL LACKING CODE TAGS >>

[quzah]

I've got an idea! See if you can guess what I'm thinking... (Note for posterity: This post is sig based. So stop trying to read my mind!)


Quzah.

[sreenu_daram]

I did not get u . Pls explain .

[swoopy]

>I did not get u . Pls explain .
Ok, let me spell it out for you. USE CODE TAGS

[sreenu_daram]

Hi Sorry! This is my code.

          #include <curl/curl.h>
          #include <curl/types.h>
          #include <curl/easy.h>


          // This is callback function
         size_t WriteMemoryCallback(void *ptr, size_t size, size_t nmemb, void *data)
        {
	       size_t realsize = size * nmemb;
	       char *memory = (char *)data;
	       /*
	       ** copy xml feed 
	       */
	       memcpy(memory, ptr, realsize);
	      /*
	      ** Add NULL at the END.
	      */
	      memory[size + realsize] = 0;
	     /*
	     ** Done
	     */
	     return realsize;

     }

    int get_payper_adknowledge(char *ename, char *etype, char *partnerid, char *affiliateid, char *subaffiliateid,                                                             double revshare, 
                        int requestid, char *keywords, char *userip, char *countrycode, 
                        int maxresults, char *results, int maxresultbuffer)
   {
	 
	 
	 char kw2[100];
	 char url[2048], errmsg[2048];
	 int stat, rcounter=0, code, bytes;
	 char tmplink[8096];
	 char title[1024];
	 char redirect[4096];
	 char desc[1024];
	 char visibleurl[1024];
	 char subaid[1024];
	 char strbidprice[25];
	 double revbid1=0.0, revbid2=0.0;
	 int roffset=0;
	 double t1=0, t2=0;
	 subaid[0]='\0';
	 results[0]='\0';
	 global_xml_buffer[0]='\0'; // global helps keep memory fragmentation down
	 url_encode(keywords, kw2);

	                                                            sprintf(url,"https://bidsystem.adknowledge.com/search.php?afid=%s&kw=%s&size=%d&ip=%s",
			  partnerid, kw2, maxresults, userip);

	/*
	** Send HTPPS Request and Gets XML feed.
	*/
	CURL *curl_handle;
	curl_global_init(CURL_GLOBAL_ALL);

	/* 
	** Init the curl session.
	*/
	curl_handle = curl_easy_init();

	/*
	** Specify URL to get.
	*/
	curl_easy_setopt(curl_handle, CURLOPT_URL, url);

	/* 
	** Send all data to this function  
	*/
	curl_easy_setopt(curl_handle, CURLOPT_WRITEFUNCTION, WriteMemoryCallback);

	/* 
	** We pass our xml buffer struct to the callback function.
	*/
	curl_easy_setopt(curl_handle, CURLOPT_WRITEDATA, (void *)global_xml_buffer);
	
        /* 
	** Some servers don't like requests that are made without a user-agent field, so we   provide one .
	*/
	curl_easy_setopt(curl_handle, CURLOPT_USERAGENT, "libcurl-agent/1.0");

	/* 
	** Get it! 
	*/
	curl_easy_perform(curl_handle);
	if (global_debug) printf("Global XML: %s \n", global_xml_buffer);

	/* 
	** Cleanup curl stuff.
	*/
	curl_easy_cleanup(curl_handle);

  }
	

  int main()
 {
	//here I am calling  get_payper_adknowledge function

 }

[quzah]

1 - Press edit.
2 - Go to the first line of code.
3 - Add this right before it:
[code]
4 - Go to the last line of code.
5 - Add this right after it:
[/code]


Quzah.

[sreenu_daram]

ok done .. Tx

[sreenu_daram]

Hi any one .. Please help me.

[quzah]

/* 
	** Send all data to this function  
	*/
	curl_easy_setopt(curl_handle, CURLOPT_WRITEFUNCTION, WriteMemoryCallback);

	/* 
	** We pass our xml buffer struct to the callback function.
	*/
	curl_easy_setopt(curl_handle, CURLOPT_WRITEDATA, (void *)global_xml_buffer);

You cannot pass a function through a void pointer. You have to use a function pointer. This means you can't use the same function argument to do both void pointers (data) and functions (function pointers).


Quzah.

[swoopy]

> memory[size + realsize] = 0;
Also I'm guessing from the memcpy that this should be:

	      memory[realsize] = 0;

Of course, unless this is a string, adding a string terminator doesn't make much sense.

[Salem]

> memory[size + realsize] = 0;
If you told something else the maximum size of the array, then this is outside the array.

void func ( char *arr, size_t maxsize );
// arr[maxsize] is OUT OF BOUNDS

char array[10];
func( array, sizeof array );

[sreenu_daram]

Thakns all of u ...