libgit2: Disable Security.framework transport on Darwin.

When used by cargo, `libgit2` crashes with a Segmentation Fault on
Darwin. This crash is somehow connected to the `Security.framework`
native to Darwin, and while being easy to reproduce, is very hard to
track down.

This commit introduces a patch to `libgit2` which disables the
troublesome transport and instead depends on `libcurl`. The patch also
adds support for `SSL_CERT_FILE` to `libgit2`.

Upstream tracking issue is
https://github.com/libgit2/libgit2/issues/3885.

2 files changed, 70 insertions, 2 deletions

diff --git a/pkgs/development/libraries/git2/default.nix b/pkgs/development/libraries/git2/default.nix
index 7aaac299b0e3..0a0c5858917f 100644
--- a/pkgs/development/libraries/git2/default.nix
+++ b/pkgs/development/libraries/git2/default.nix
@@ -1,4 +1,4 @@
-{ stdenv, fetchurl, pkgconfig, cmake, zlib, python, libssh2, openssl, http-parser, libiconv }:
+{ stdenv, fetchurl, pkgconfig, cmake, zlib, python, libssh2, openssl, curl, http-parser, libiconv }:
 
 stdenv.mkDerivation (rec {
   version = "0.24.1";
@@ -10,10 +10,20 @@ stdenv.mkDerivation (rec {
     sha256 = "0rw80480dx2f6a2wbb1bwixygg1iwq3r7vwhxdmkkf4lpxd35jhd";
   };
 
+  # TODO: `cargo` (rust's package manager) surfaced a serious bug in
+  # libgit2 when the `Security.framework` transport is used on Darwin.
+  # The upstream issue is tracked at
+  # https://github.com/libgit2/libgit2/issues/3885 - feel free to
+  # remove this patch as soon as it's resolved (i.E. when cargo is
+  # working fine without this patch)
+  patches = stdenv.lib.optionals stdenv.isDarwin [
+    ./disable-security.framework.patch
+  ];
+
   cmakeFlags = "-DTHREADSAFE=ON";
 
   nativeBuildInputs = [ cmake python pkgconfig ];
-  buildInputs = [ zlib libssh2 openssl http-parser ];
+  buildInputs = [ zlib libssh2 openssl http-parser curl ];
 
   meta = {
     description = "The Git linkable library";
diff --git a/pkgs/development/libraries/git2/disable-security.framework.patch b/pkgs/development/libraries/git2/disable-security.framework.patch
new file mode 100644
index 000000000000..ce6a008b1c4c
--- /dev/null
+++ b/pkgs/development/libraries/git2/disable-security.framework.patch
@@ -0,0 +1,58 @@
+From fbc2ea65406236a740b8734dd41dc5ddbc24f8c9 Mon Sep 17 00:00:00 2001
+From: mulrich <mulrich@entwicklerheld.local>
+Date: Mon, 8 Aug 2016 15:36:07 +0200
+Subject: [PATCH] disable security.framework
+
+---
+ CMakeLists.txt    | 7 +++----
+ src/curl_stream.c | 9 ++++++++-
+ 2 files changed, 11 insertions(+), 5 deletions(-)
+
+diff --git a/CMakeLists.txt b/CMakeLists.txt
+index 93a9e47..331e148 100644
+--- a/CMakeLists.txt
++++ b/CMakeLists.txt
+@@ -49,7 +49,8 @@ ENDIF()
+ 
+ IF(${CMAKE_SYSTEM_NAME} MATCHES "Darwin")
+ 	SET( USE_ICONV ON )
+-	FIND_PACKAGE(Security)
++	# FIND_PACKAGE(Security)
++  SET(SECURITY_FOUND "NO")
+ 	FIND_PACKAGE(CoreFoundation REQUIRED)
+ ENDIF()
+ 
+@@ -87,9 +88,7 @@ IF(MSVC)
+ 	OPTION(MSVC_CRTDBG "Enable CRTDBG memory leak reporting" OFF)
+ ENDIF()
+ 
+-IF (NOT ${CMAKE_SYSTEM_NAME} MATCHES "Darwin")
+-	OPTION( USE_OPENSSL                     "Link with and use openssl library"             ON )
+-ENDIF()
++OPTION( USE_OPENSSL                     "Link with and use openssl library"             ON )
+ 
+ CHECK_STRUCT_HAS_MEMBER ("struct stat" st_mtim "sys/types.h;sys/stat.h"
+ 	HAVE_STRUCT_STAT_ST_MTIM LANGUAGE C)
+diff --git a/src/curl_stream.c b/src/curl_stream.c
+index 98de187..a8a9f4c 100644
+--- a/src/curl_stream.c
++++ b/src/curl_stream.c
+@@ -309,7 +309,14 @@ int git_curl_stream_new(git_stream **out, const char *host, const char *port)
+ 	curl_easy_setopt(handle, CURLOPT_HTTPPROXYTUNNEL, 1);
+ 	curl_easy_setopt(handle, CURLOPT_PROXYAUTH, CURLAUTH_ANY);
+ 
+-	/* curl_easy_setopt(handle, CURLOPT_VERBOSE, 1); */
++  const char* cainfo = getenv("SSL_CERT_FILE");
++  if(cainfo != NULL) {
++    curl_easy_setopt(handle, CURLOPT_CAINFO, cainfo);
++  }
++
++  /*
++	curl_easy_setopt(handle, CURLOPT_VERBOSE, 1);
++  */
+ 
+ 	st->parent.version = GIT_STREAM_VERSION;
+ 	st->parent.encrypted = 0; /* we don't encrypt ourselves */
+-- 
+2.3.8 (Apple Git-58)
+