Unverified Commit fb4f568b authored by Daniel Stenberg's avatar Daniel Stenberg
Browse files

add_handle/easy_perform: clear errorbuffer on start if set 

To offer applications a more defined behavior, we clear the buffer as
early as possible.

Assisted-by: Jay Satiro

Fixes #2190
Closes #2377
parent 6baeb6df

docs/libcurl/opts/CURLOPT_ERRORBUFFER.3

+7 −5
Original line number Diff line number Diff line
@@ -28,8 +28,8 @@ CURLOPT_ERRORBUFFER \- set error buffer for error messages 


CURLcode curl_easy_setopt(CURL *handle, CURLOPT_ERRORBUFFER, char *buf);

.SH DESCRIPTION

Pass a char * to a buffer that the libcurl may store human readable error

messages in on failures or problems. This may be more helpful than just the

Pass a char * to a buffer that libcurl \fBmay\fP store human readable error

messages on failures or problems. This may be more helpful than just the

return code from \fIcurl_easy_perform(3)\fP and related functions. The buffer

\fBmust be at least CURL_ERROR_SIZE bytes big\fP.
@@ -38,11 +38,13 @@ it. Failing to do so will cause very odd behavior or even crashes. libcurl 
will need it until you call \fIcurl_easy_cleanup(3)\fP or you set the same

option again to use a different pointer.



Do not rely on the contents of the buffer unless an error code was returned.

Since 7.60.0 libcurl will initialize the contents of the error buffer to an

empty string before performing the transfer. For earlier versions if an error

code was returned but there was no error detail then the buffer is untouched.



Consider \fICURLOPT_VERBOSE(3)\fP and \fICURLOPT_DEBUGFUNCTION(3)\fP to better

debug and trace why errors happen.



If the library does not return an error, the buffer may not have been

touched. Do not rely on the contents in those cases.

.SH DEFAULT

NULL

.SH PROTOCOLS

lib/easy.c

+4 −0
Original line number Diff line number Diff line
@@ -746,6 +746,10 @@ static CURLcode easy_perform(struct Curl_easy *data, bool events) 
  if(!data)

    return CURLE_BAD_FUNCTION_ARGUMENT;



  if(data->set.errorbuffer)

    /* clear this as early as possible */

    data->set.errorbuffer[0] = 0;



  if(data->multi) {

    failf(data, "easy handle already used in multi handle");

    return CURLE_FAILED_INIT;

lib/multi.c

+2 −0
Original line number Diff line number Diff line
@@ -379,6 +379,8 @@ CURLMcode curl_multi_add_handle(struct Curl_multi *multi, 
   * potential multi's connection cache growing which won't be undone in this

   * function no matter what.

   */

  if(data->set.errorbuffer)

    data->set.errorbuffer[0] = 0;



  /* set the easy handle */

  multistate(data, CURLM_STATE_INIT);