curl: fix --upload-file . hangs if delay in STDIN

Attempt to unpause a busy read in the CURLOPT_XFERINFOFUNCTION.

When uploading from stdin in non-blocking mode, a delay in reading
the stream (EAGAIN) causes curl to pause sending data
(CURL_READFUNC_PAUSE).  Prior to this change, a busy read was
detected and unpaused only in the CURLOPT_WRITEFUNCTION handler.
This change performs the same busy read handling in a
CURLOPT_XFERINFOFUNCTION handler.

Fixes #2051
Closes #4599
Reported-by: bdry on github

1 files changed, 26 insertions, 0 deletions

diff --git a/src/tool_cb_rea.c b/src/tool_cb_rea.c
index 06f60eca7..03ed4a467 100644
--- a/src/tool_cb_rea.c
+++ b/src/tool_cb_rea.c
@@ -27,6 +27,7 @@
 
 #include "tool_cfgable.h"
 #include "tool_cb_rea.h"
+#include "tool_operate.h"
 
 #include "memdebug.h" /* keep this as LAST include */
 
@@ -52,3 +53,28 @@ size_t tool_read_cb(void *buffer, size_t sz, size_t nmemb, void *userdata)
   in->config->readbusy = FALSE;
   return (size_t)rc;
 }
+
+/*
+** callback for CURLOPT_XFERINFOFUNCTION used to unpause busy reads
+*/
+
+int tool_readbusy_cb(void *clientp,
+                     curl_off_t dltotal, curl_off_t dlnow,
+                     curl_off_t ultotal, curl_off_t ulnow)
+{
+  struct per_transfer *per = clientp;
+  struct OutStruct *outs = &per->outs;
+  struct OperationConfig *config = outs->config;
+
+  (void)dltotal;  /* unused */
+  (void)dlnow;  /* unused */
+  (void)ultotal;  /* unused */
+  (void)ulnow;  /* unused */
+
+  if(config->readbusy) {
+    config->readbusy = FALSE;
+    curl_easy_pause(per->curl, CURLPAUSE_CONT);
+  }
+
+  return per->noprogress? 0 : CURL_PROGRESSFUNC_CONTINUE;
+}