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

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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
This commit is contained in:
Daniel Stenberg 2013-12-26 23:50:34 +01:00
parent f88f9bed00
commit 2a4ee0d221
3 changed files with 33 additions and 11 deletions
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8
docs/libcurl/curl_easy_pause.3
View File

@ -31,8 +31,8 @@ curl_easy_pause - pause and unpause a connection
Using this function, you can explicitly mark a running connection to get
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
or the write callbacks return the proper magic return code
A connection can be paused by using this function or by letting the read or
the write callbacks return the proper magic return code
(\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
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
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.
.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
This function was added in libcurl 7.18.0. Before this version, there was no
explicit support for pausing transfers.

12
lib/sendf.c
View File

@ -444,10 +444,18 @@ CURLcode Curl_client_write(struct connectdata *conn,
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);
if(wrote != len) {
else if(wrote != len) {
failf(data, "Failed writing body (%zu != %zu)", wrote, len);
return CURLE_WRITE_ERROR;
}

24
lib/transfer.c
View File

@ -128,14 +128,24 @@ CURLcode Curl_fillreadbuffer(struct connectdata *conn, int bytes, int *nreadp)
return CURLE_ABORTED_BY_CALLBACK;
}
else if(nread == CURL_READFUNC_PAUSE) {
struct SingleRequest *k = &data->req;
/* CURL_READFUNC_PAUSE pauses read callbacks that feed socket writes */
k->keepon |= KEEP_SEND_PAUSE; /* mark socket send as paused */
if(data->req.upload_chunky) {
/* Back out the preallocation done above */
data->req.upload_fromhere -= (8 + 2);
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;
/* CURL_READFUNC_PAUSE pauses read callbacks that feed socket writes */
k->keepon |= KEEP_SEND_PAUSE; /* mark socket send as paused */
if(data->req.upload_chunky) {
/* Back out the preallocation done above */
data->req.upload_fromhere -= (8 + 2);
}
*nreadp = 0;
}
*nreadp = 0;
return CURLE_OK; /* nothing was read */
}
else if((size_t)nread > buffersize) {