Bugs item #1465999, was opened at 2006-04-06 23:34
Message generated for change (Comment added) made by bagder
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Category: ftp
Group: bad behaviour
Status: Open
>Resolution: Accepted
>Priority: 2
Submitted By: Robson Braga Araujo (braga)
Assigned to: Daniel Stenberg (bagder)
Summary: Libcurl doesn't reuse connection after aborting transfer.

Initial Comment:
Libcurl disconnects from the FTP server when I remove
the easy handle from a multi handle to stop the
transfer. This is not necessary as libcurl maintains
the connection if I pass a range of the form X-Y. The
following testcase shows this bad behaviour. I tested
it against latest CVS (7.15.3-20060406).

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

int main() {
  CURL *c;
  CURLM *m;
  CURLMcode res;
  int running=1;
  int i=0;

  curl_global_init(CURL_GLOBAL_ALL);
  c = curl_easy_init();
  curl_easy_setopt(c, CURLOPT_VERBOSE, 1);
  curl_easy_setopt(c, CURLOPT_URL, "ftp://ftp.sunet.se/");
  curl_easy_perform(c);
  curl_easy_setopt(c, CURLOPT_URL,
"ftp://ftp.sunet.se/ls-lR");
  m = curl_multi_init();

  res = curl_multi_add_handle(m, c);

  do {
     res = curl_multi_perform(m, &running);
  } while (res==CURLM_CALL_MULTI_PERFORM);
  while (running) {
    struct timeval timeout;
    int rc; /* select() return code */

    fd_set fdread;
    fd_set fdwrite;
    fd_set fdexcep;
    int maxfd;

    FD_ZERO(&fdread);
    FD_ZERO(&fdwrite);
    FD_ZERO(&fdexcep);

    /* set a suitable timeout to play around with */
    timeout.tv_sec = 1;
    timeout.tv_usec = 0;

    /* get file descriptors from the transfers */
    curl_multi_fdset(m, &fdread, &fdwrite, &fdexcep,
&maxfd);

    rc = select(maxfd+1, &fdread, &fdwrite, &fdexcep,
&timeout);

    switch(rc) {
    case -1:
      /* select error */
      break;
    case 0:
      /* timeout, do something else */
      break;
    default:
      /* one or more of curl's file descriptors say
there's data to read
         or write */
      while(CURLM_CALL_MULTI_PERFORM ==
            curl_multi_perform(m, &running));
      break;
    }
    if (i++ > 10) break;
  }

  curl_multi_remove_handle(m, c);
  curl_easy_setopt(c, CURLOPT_URL, "ftp://ftp.sunet.se");
  res = curl_multi_add_handle(m, c);

  while (running) {
    res = curl_multi_perform(m, &running);
    if (running <= 0) {
      fprintf(stderr, "nothing left running.\n");
      break;
    }
  }
  curl_multi_remove_handle(m, c);
  curl_easy_cleanup(c);
  curl_multi_cleanup(m);

  return res;
}

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>Comment By: Daniel Stenberg (bagder)
Date: 2006-04-07 14:37

Message:
Logged In: YES
user_id=1110

I agree it could re-use such connections and that libcurl is
doing this to "play safe" atm.

I have no immediate plans to work on this myself, but I'll
leave this bug report open for a while should anyone else
feel like taking a stab at fixing this.

----------------------------------------------------------------------

You can respond by visiting:
https://sourceforge.net/tracker/?func=detail&atid=100976&aid=1465999&group_id=976
Received on 2006-04-07