[curl/f19] avoid a busy-loop in curl_easy_perform()

[Kamil Dudka]

commit 68cb5f29336af9dcee4fff3835305b867e20d78e
Author: Kamil Dudka <kdudka at redhat.com>
Date:   Wed Sep 4 18:41:43 2013 +0200

    avoid a busy-loop in curl_easy_perform()

 0011-curl-7.29.0-0feeab78.patch |   74 +++++++++++++++++++++++++++++++++++++++
 curl.spec                       |    9 ++++-
 2 files changed, 82 insertions(+), 1 deletions(-)
---
diff --git a/0011-curl-7.29.0-0feeab78.patch b/0011-curl-7.29.0-0feeab78.patch
new file mode 100644
index 0000000..bd6b8b3
--- /dev/null
+++ b/0011-curl-7.29.0-0feeab78.patch
@@ -0,0 +1,74 @@
+From d3036f34cce421990e8268ee4bbfc0d9f5ceb054 Mon Sep 17 00:00:00 2001
+From: Daniel Stenberg <daniel at haxx.se>
+Date: Thu, 13 Jun 2013 19:27:12 +0200
+Subject: [PATCH] curl_easy_perform: avoid busy-looping
+
+When curl_multi_wait() finds no file descriptor to wait for, it returns
+instantly and this must be handled gracefully within curl_easy_perform()
+or cause a busy-loop. Starting now, repeated fast returns without any
+file descriptors is detected and a gradually increasing sleep will be
+used (up to a max of 1000 milliseconds) before continuing the loop.
+
+Bug: http://curl.haxx.se/bug/view.cgi?id=1238
+Reported-by: Miguel Angel
+
+[upstream commit 0feeab7802dd2a6465d22d153d8d36b2cca99b96]
+
+Signed-off-by: Kamil Dudka <kdudka at redhat.com>
+---
+ lib/easy.c |   25 +++++++++++++++++++++++++
+ 1 files changed, 25 insertions(+), 0 deletions(-)
+
+diff --git a/lib/easy.c b/lib/easy.c
+index 2739598..a7051dd 100644
+--- a/lib/easy.c
++++ b/lib/easy.c
+@@ -410,6 +410,9 @@ CURLcode curl_easy_perform(CURL *easy)
+   bool done = FALSE;
+   int rc;
+   struct SessionHandle *data = easy;
++  int without_fds = 0;  /* count number of consecutive returns from
++                           curl_multi_wait() without any filedescriptors */
++  struct timeval before;
+ 
+   if(!easy)
+     return CURLE_BAD_FUNCTION_ARGUMENT;
+@@ -445,6 +448,7 @@ CURLcode curl_easy_perform(CURL *easy)
+     int still_running;
+     int ret;
+ 
++    before = curlx_tvnow();
+     mcode = curl_multi_wait(multi, NULL, 0, 1000, &ret);
+ 
+     if(mcode == CURLM_OK) {
+@@ -453,6 +457,27 @@ CURLcode curl_easy_perform(CURL *easy)
+         code = CURLE_RECV_ERROR;
+         break;
+       }
++      else if(ret == 0) {
++        struct timeval after = curlx_tvnow();
++        /* If it returns without any filedescriptor instantly, we need to
++           avoid busy-looping during periods where it has nothing particular
++           to wait for */
++        if(curlx_tvdiff(after, before) <= 10) {
++          without_fds++;
++          if(without_fds > 2) {
++            int sleep_ms = without_fds * 50;
++            if(sleep_ms > 1000)
++              sleep_ms = 1000;
++            Curl_wait_ms(sleep_ms);
++          }
++        }
++        else
++          /* it wasn't "instant", restart counter */
++          without_fds = 0;
++      }
++      else
++        /* got file descriptor, restart counter */
++        without_fds = 0;
+ 
+       mcode = curl_multi_perform(multi, &still_running);
+     }
+-- 
+1.7.1
+
diff --git a/curl.spec b/curl.spec
index 34e6562..506a0ca 100644
--- a/curl.spec
+++ b/curl.spec
@@ -1,7 +1,7 @@
 Summary: A utility for getting files from remote servers (FTP, HTTP, and others)
 Name: curl
 Version: 7.29.0
-Release: 9%{?dist}
+Release: 10%{?dist}
 License: MIT
 Group: Applications/Internet
 Source: http://curl.haxx.se/download/%{name}-%{version}.tar.lzma
@@ -37,6 +37,9 @@ Patch9: 0009-curl-7.29.0-3a0e931f.patch
 # FTP: when EPSV gets a 229 but fails to connect, retry with PASV (#1002815)
 Patch10: 0010-curl-7.29.0-7cc00d9a.patch
 
+# avoid a busy-loop in curl_easy_perform() 
+Patch11: 0011-curl-7.29.0-0feeab78.patch
+
 # patch making libcurl multilib ready
 Patch101: 0101-curl-7.29.0-multilib.patch
 
@@ -140,6 +143,7 @@ documentation of the library, too.
 %patch8 -p1
 %patch9 -p1
 %patch10 -p1
+%patch11 -p1
 
 # Fedora patches
 %patch101 -p1
@@ -257,6 +261,9 @@ rm -rf $RPM_BUILD_ROOT
 %{_datadir}/aclocal/libcurl.m4
 
 %changelog
+* Wed Sep 04 2013 Kamil Dudka <kdudka at redaht.com> 7.29.0-10
+- avoid a busy-loop in curl_easy_perform() 
+
 * Fri Aug 30 2013 Kamil Dudka <kdudka at redaht.com> 7.29.0-9
 - FTP: when EPSV gets a 229 but fails to connect, retry with PASV (#1002815)