Commit 2a4ee0d2 authored by Daniel Stenberg's avatar Daniel Stenberg
Browse files

FILE: we don't support paused transfers using this protocol 

Make sure that we detect such attempts and return a proper error code
instead of silently handling this in problematic ways.

Updated the documentation to mention this limitation.

Bug: http://curl.haxx.se/bug/view.cgi?id=1286
parent f88f9bed

docs/libcurl/curl_easy_pause.3

+6 −2
Original line number Original line Diff line number Diff line
@@ -31,8 +31,8 @@ curl_easy_pause - pause and unpause a connection 
Using this function, you can explicitly mark a running connection to get

Using this function, you can explicitly mark a running connection to get

paused, and you can unpause a connection that was previously paused.

paused, and you can unpause a connection that was previously paused.





A connection can be paused by using this function or by letting the read

A connection can be paused by using this function or by letting the read or

or the write callbacks return the proper magic return code

the write callbacks return the proper magic return code

(\fICURL_READFUNC_PAUSE\fP and \fICURL_WRITEFUNC_PAUSE\fP). A write callback

(\fICURL_READFUNC_PAUSE\fP and \fICURL_WRITEFUNC_PAUSE\fP). A write callback

that returns pause signals to the library that it couldn't take care of any

that returns pause signals to the library that it couldn't take care of any

data at all, and that data will then be delivered again to the callback when

data at all, and that data will then be delivered again to the callback when
@@ -68,6 +68,10 @@ Convenience define that unpauses both directions 
CURLE_OK (zero) means that the option was set properly, and a non-zero return

CURLE_OK (zero) means that the option was set properly, and a non-zero return

code means something wrong occurred after the new state was set.  See the

code means something wrong occurred after the new state was set.  See the

\fIlibcurl-errors(3)\fP man page for the full list with descriptions.

\fIlibcurl-errors(3)\fP man page for the full list with descriptions.

.SH LIMITATIONS

The pausing of transfers does not work with protocols that work without

network connectivity, like FILE://. Trying to pause such a transfer, in any

direction, will cause problems in the worst case or an error in the best case.

.SH AVAILABILITY

.SH AVAILABILITY

This function was added in libcurl 7.18.0. Before this version, there was no

This function was added in libcurl 7.18.0. Before this version, there was no

explicit support for pausing transfers.

explicit support for pausing transfers.

lib/sendf.c

+10 −2
Original line number Original line Diff line number Diff line
@@ -444,10 +444,18 @@ CURLcode Curl_client_write(struct connectdata *conn, 
      wrote = len;

      wrote = len;

    }

    }





    if(CURL_WRITEFUNC_PAUSE == wrote)

    if(conn->handler->flags & PROTOPT_NONETWORK) {

      /* protocols that work without network cannot be paused. This is

         actually only FILE:// just now, and it can't pause since the transfer

         isn't done using the "normal" procedure. */

      failf(data, "Write callback asked for PAUSE when not supported!");

      return CURLE_WRITE_ERROR;

    }



    else if(CURL_WRITEFUNC_PAUSE == wrote)

      return pausewrite(data, type, ptr, len);

      return pausewrite(data, type, ptr, len);





    if(wrote != len) {

    else if(wrote != len) {

      failf(data, "Failed writing body (%zu != %zu)", wrote, len);

      failf(data, "Failed writing body (%zu != %zu)", wrote, len);

      return CURLE_WRITE_ERROR;

      return CURLE_WRITE_ERROR;

    }

    }

lib/transfer.c

+17 −7
Original line number Original line Diff line number Diff line
@@ -128,6 +128,15 @@ CURLcode Curl_fillreadbuffer(struct connectdata *conn, int bytes, int *nreadp) 
    return CURLE_ABORTED_BY_CALLBACK;

    return CURLE_ABORTED_BY_CALLBACK;

  }

  }

  else if(nread == CURL_READFUNC_PAUSE) {

  else if(nread == CURL_READFUNC_PAUSE) {



    if(conn->handler->flags & PROTOPT_NONETWORK) {

      /* protocols that work without network cannot be paused. This is

         actually only FILE:// just now, and it can't pause since the transfer

         isn't done using the "normal" procedure. */

      failf(data, "Read callback asked for PAUSE when not supported!");

      return CURLE_READ_ERROR;

    }

    else {

      struct SingleRequest *k = &data->req;

      struct SingleRequest *k = &data->req;

      /* CURL_READFUNC_PAUSE pauses read callbacks that feed socket writes */

      /* CURL_READFUNC_PAUSE pauses read callbacks that feed socket writes */

      k->keepon |= KEEP_SEND_PAUSE; /* mark socket send as paused */

      k->keepon |= KEEP_SEND_PAUSE; /* mark socket send as paused */
@@ -136,6 +145,7 @@ CURLcode Curl_fillreadbuffer(struct connectdata *conn, int bytes, int *nreadp) 
        data->req.upload_fromhere -= (8 + 2);

        data->req.upload_fromhere -= (8 + 2);

      }

      }

      *nreadp = 0;

      *nreadp = 0;

    }

    return CURLE_OK; /* nothing was read */

    return CURLE_OK; /* nothing was read */

  }

  }

  else if((size_t)nread > buffersize) {

  else if((size_t)nread > buffersize) {