streams: sockets are non-blocking and can timeout

Make socket I/O non-blocking and add optional timeouts.

Users may now set `GIT_OPT_SET_SERVER_CONNECT_TIMEOUT` to set a shorter
connection timeout. (The connect timeout cannot be longer than the
operating system default.) Users may also now configure the socket read
and write timeouts with `GIT_OPT_SET_SERVER_TIMEOUT`.

By default, connects still timeout based on the operating system
defaults (typically 75 seconds) and socket read and writes block.

Add a test against our custom testing git server that ensures that we
can timeout reads against a slow server.

2 files changed, 61 insertions, 1 deletions

diff --git a/tests/libgit2/CMakeLists.txt b/tests/libgit2/CMakeLists.txt
index 866122d1c..af70f55a7 100644
--- a/tests/libgit2/CMakeLists.txt
+++ b/tests/libgit2/CMakeLists.txt
@@ -65,7 +65,7 @@ endif()
 
 include(AddClarTest)
 add_clar_test(libgit2_tests offline             -v -xonline)
-add_clar_test(libgit2_tests invasive            -v -sfilter::stream::bigfile -sodb::largefiles -siterator::workdir::filesystem_gunk -srepo::init -srepo::init::at_filesystem_root)
+add_clar_test(libgit2_tests invasive            -v -sfilter::stream::bigfile -sodb::largefiles -siterator::workdir::filesystem_gunk -srepo::init -srepo::init::at_filesystem_root -sonline::clone::connect_timeout_default)
 add_clar_test(libgit2_tests online              -v -sonline -xonline::customcert)
 add_clar_test(libgit2_tests online_customcert   -v -sonline::customcert)
 add_clar_test(libgit2_tests gitdaemon           -v -sonline::push)
diff --git a/tests/libgit2/online/clone.c b/tests/libgit2/online/clone.c
index b635739b6..92fa4d351 100644
--- a/tests/libgit2/online/clone.c
+++ b/tests/libgit2/online/clone.c
@@ -35,6 +35,8 @@ static char *_remote_proxy_selfsigned = NULL;
 static char *_remote_expectcontinue = NULL;
 static char *_remote_redirect_initial = NULL;
 static char *_remote_redirect_subsequent = NULL;
+static char *_remote_speed_timesout = NULL;
+static char *_remote_speed_slow = NULL;
 
 static char *_github_ssh_pubkey = NULL;
 static char *_github_ssh_privkey = NULL;
@@ -89,6 +91,8 @@ void test_online_clone__initialize(void)
 	_remote_expectcontinue = cl_getenv("GITTEST_REMOTE_EXPECTCONTINUE");
 	_remote_redirect_initial = cl_getenv("GITTEST_REMOTE_REDIRECT_INITIAL");
 	_remote_redirect_subsequent = cl_getenv("GITTEST_REMOTE_REDIRECT_SUBSEQUENT");
+	_remote_speed_timesout = cl_getenv("GITTEST_REMOTE_SPEED_TIMESOUT");
+	_remote_speed_slow = cl_getenv("GITTEST_REMOTE_SPEED_SLOW");
 
 	_github_ssh_pubkey = cl_getenv("GITTEST_GITHUB_SSH_PUBKEY");
 	_github_ssh_privkey = cl_getenv("GITTEST_GITHUB_SSH_KEY");
@@ -128,6 +132,8 @@ void test_online_clone__cleanup(void)
 	git__free(_remote_expectcontinue);
 	git__free(_remote_redirect_initial);
 	git__free(_remote_redirect_subsequent);
+	git__free(_remote_speed_timesout);
+	git__free(_remote_speed_slow);
 
 	git__free(_github_ssh_pubkey);
 	git__free(_github_ssh_privkey);
@@ -145,6 +151,8 @@ void test_online_clone__cleanup(void)
 	}
 
 	git_libgit2_opts(GIT_OPT_SET_SSL_CERT_LOCATIONS, NULL, NULL);
+	git_libgit2_opts(GIT_OPT_SET_SERVER_TIMEOUT, 0);
+	git_libgit2_opts(GIT_OPT_SET_SERVER_CONNECT_TIMEOUT, 0);
 }
 
 void test_online_clone__network_full(void)
@@ -1207,3 +1215,55 @@ void test_online_clone__sha256(void)
 	git_reference_free(head);
 #endif
 }
+
+void test_online_clone__connect_timeout_configurable(void)
+{
+	uint64_t start, finish;
+
+	start = git_time_monotonic();
+
+	cl_git_pass(git_libgit2_opts(GIT_OPT_SET_SERVER_CONNECT_TIMEOUT, 1));
+	cl_git_fail(git_clone(&g_repo, "http://www.google.com:8000/", "./timedout", NULL));
+	cl_assert(git_error_last() && strstr(git_error_last()->message, "timed out"));
+
+	finish = git_time_monotonic();
+
+	cl_assert(finish - start < 1000);
+}
+
+void test_online_clone__connect_timeout_default(void)
+{
+	/* This test takes ~ 75 seconds on Unix. */
+	if (!cl_is_env_set("GITTEST_INVASIVE_SPEED"))
+		cl_skip();
+
+	/*
+	 * Use a host/port pair that blackholes packets and does not
+	 * send an RST.
+	 */
+	cl_git_fail_with(GIT_TIMEOUT, git_clone(&g_repo, "http://www.google.com:8000/", "./refused", NULL));
+	cl_assert(git_error_last() && strstr(git_error_last()->message, "timed out"));
+}
+
+void test_online_clone__timeout_configurable_times_out(void)
+{
+	git_repository *failed_repo;
+
+	if (!_remote_speed_timesout)
+		cl_skip();
+
+	cl_git_pass(git_libgit2_opts(GIT_OPT_SET_SERVER_TIMEOUT, 1000));
+
+	cl_git_fail_with(GIT_TIMEOUT, git_clone(&failed_repo, _remote_speed_timesout, "./timedout", NULL));
+	cl_assert(git_error_last() && strstr(git_error_last()->message, "timed out"));
+}
+
+void test_online_clone__timeout_configurable_succeeds_slowly(void)
+{
+	if (!_remote_speed_slow)
+		cl_skip();
+
+	cl_git_pass(git_libgit2_opts(GIT_OPT_SET_SERVER_TIMEOUT, 1000));
+
+	cl_git_pass(git_clone(&g_repo, _remote_speed_slow, "./slow-but-successful", NULL));
+}