ssh: GIT_SSH_LIBSSH2 is now distinct from GIT_SSH

We may want to support SSH but with a different provider that is not
libssh2. Add GIT_SSH to indicate that we have some inbuilt SSH support
and GIT_SSH_LIBSSH2 to indicate that support is via libssh2. This is
similar to how we support GIT_HTTPS and GIT_OPENSSL, for example.

CMakeLists.txt

@@ -30,7 +30,7 @@ option(USE_THREADS             "Use threads for parallel processing when possibl
 option(USE_NSEC                "Support nanosecond precision file mtimes and ctimes"    ON)
 
 # Backend selection
-option(USE_SSH                 "Link with libssh2 to enable SSH support"               OFF)
+option(USE_SSH                 "Enable SSH support. Can be set to a specific backend" OFF)
 option(USE_HTTPS               "Enable HTTPS support. Can be set to a specific backend" ON)
 option(USE_SHA1                "Enable SHA1. Can be set to CollisionDetection(ON)/HTTPS" ON)
 option(USE_SHA256              "Enable SHA256. Can be set to HTTPS/Builtin" ON)

cmake/SelectSSH.cmake

-# Optional external dependency: libssh2
-if(USE_SSH)
+# find libssh2
+if(USE_SSH STREQUAL ON OR USE_SSH STREQUAL "libssh2")
 	find_pkglibraries(LIBSSH2 libssh2)
+
 	if(NOT LIBSSH2_FOUND)
 		find_package(LibSSH2)
 		set(LIBSSH2_INCLUDE_DIRS ${LIBSSH2_INCLUDE_DIR})
@@ -12,30 +13,28 @@ if(USE_SSH)
 	if(NOT LIBSSH2_FOUND)
 		message(FATAL_ERROR "LIBSSH2 not found. Set CMAKE_PREFIX_PATH if it is installed outside of the default search path.")
 	endif()
-endif()
 
-if(LIBSSH2_FOUND)
-	set(GIT_SSH 1)
 	list(APPEND LIBGIT2_SYSTEM_INCLUDES ${LIBSSH2_INCLUDE_DIRS})
 	list(APPEND LIBGIT2_SYSTEM_LIBS ${LIBSSH2_LIBRARIES})
 	list(APPEND LIBGIT2_PC_LIBS ${LIBSSH2_LDFLAGS})
 
 	check_library_exists("${LIBSSH2_LIBRARIES}" libssh2_userauth_publickey_frommemory "${LIBSSH2_LIBRARY_DIRS}" HAVE_LIBSSH2_MEMORY_CREDENTIALS)
 	if(HAVE_LIBSSH2_MEMORY_CREDENTIALS)
-		set(GIT_SSH_MEMORY_CREDENTIALS 1)
+		set(GIT_SSH_LIBSSH2_MEMORY_CREDENTIALS 1)
 	endif()
-else()
-	message(STATUS "LIBSSH2 not found. Set CMAKE_PREFIX_PATH if it is installed outside of the default search path.")
-endif()
 
-if(WIN32 AND EMBED_SSH_PATH)
-	file(GLOB SSH_SRC "${EMBED_SSH_PATH}/src/*.c")
-	list(SORT SSH_SRC)
-	list(APPEND LIBGIT2_DEPENDENCY_OBJECTS ${SSH_SRC})
+	if(WIN32 AND EMBED_SSH_PATH)
+		file(GLOB SSH_SRC "${EMBED_SSH_PATH}/src/*.c")
+		list(SORT SSH_SRC)
+		list(APPEND LIBGIT2_DEPENDENCY_OBJECTS ${SSH_SRC})
+
+		list(APPEND LIBGIT2_DEPENDENCY_INCLUDES "${EMBED_SSH_PATH}/include")
+		file(WRITE "${EMBED_SSH_PATH}/src/libssh2_config.h" "#define HAVE_WINCNG\n#define LIBSSH2_WINCNG\n#include \"../win32/libssh2_config.h\"")
+	endif()
 
-	list(APPEND LIBGIT2_DEPENDENCY_INCLUDES "${EMBED_SSH_PATH}/include")
-	file(WRITE "${EMBED_SSH_PATH}/src/libssh2_config.h" "#define HAVE_WINCNG\n#define LIBSSH2_WINCNG\n#include \"../win32/libssh2_config.h\"")
 	set(GIT_SSH 1)
+	set(GIT_SSH_LIBSSH2 1)
+	add_feature_info(SSH ON "using libssh2")
+else()
+	add_feature_info(SSH OFF "SSH transport support")
 endif()
-
-add_feature_info(SSH GIT_SSH "SSH transport support")

src/libgit2/libgit2.c

@@ -126,10 +126,10 @@ int git_libgit2_features(void)
 #ifdef GIT_HTTPS
 		| GIT_FEATURE_HTTPS
 #endif
-#if defined(GIT_SSH)
+#ifdef GIT_SSH
 		| GIT_FEATURE_SSH
 #endif
-#if defined(GIT_USE_NSEC)
+#ifdef GIT_USE_NSEC
 		| GIT_FEATURE_NSEC
 #endif
 	;

src/libgit2/transport.c

@@ -22,6 +22,7 @@ typedef struct transport_definition {
 
 static git_smart_subtransport_definition http_subtransport_definition = { git_smart_subtransport_http, 1, NULL };
 static git_smart_subtransport_definition git_subtransport_definition = { git_smart_subtransport_git, 0, NULL };
+
 #ifdef GIT_SSH
 static git_smart_subtransport_definition ssh_subtransport_definition = { git_smart_subtransport_ssh, 0, NULL };
 #endif
@@ -33,11 +34,13 @@ static transport_definition transports[] = {
 	{ "http://",  git_transport_smart, &http_subtransport_definition },
 	{ "https://", git_transport_smart, &http_subtransport_definition },
 	{ "file://",  git_transport_local, NULL },
+
 #ifdef GIT_SSH
 	{ "ssh://",   git_transport_smart, &ssh_subtransport_definition },
 	{ "ssh+git://",   git_transport_smart, &ssh_subtransport_definition },
 	{ "git+ssh://",   git_transport_smart, &ssh_subtransport_definition },
 #endif
+
 	{ NULL, 0, 0 }
 };
 

src/libgit2/transports/credential.c

@@ -204,7 +204,7 @@ int git_credential_ssh_key_memory_new(
 	const char *privatekey,
 	const char *passphrase)
 {
-#ifdef GIT_SSH_MEMORY_CREDENTIALS
+#ifdef GIT_SSH_LIBSSH2_MEMORY_CREDENTIALS
 	return git_credential_ssh_key_type_new(
 		cred,
 		username,

src/libgit2/transports/ssh.c

@@ -14,7 +14,7 @@ int git_smart_subtransport_ssh(
 	git_transport *owner,
 	void *param)
 {
-#ifdef GIT_SSH
+#ifdef GIT_SSH_LIBSSH2
 	return git_smart_subtransport_ssh_libssh2(out, owner, param);
 #else
 	GIT_UNUSED(out);
@@ -31,7 +31,7 @@ int git_transport_ssh_with_paths(
 	git_remote *owner,
 	void *payload)
 {
-#ifdef GIT_SSH
+#ifdef GIT_SSH_LIBSSH2
 	git_strarray *paths = (git_strarray *) payload;
 	git_transport *transport;
 	transport_smart *smart;

src/libgit2/transports/ssh_libssh2.c

@@ -7,7 +7,7 @@
 
 #include "ssh_libssh2.h"
 
-#ifdef GIT_SSH
+#ifdef GIT_SSH_LIBSSH2
 
 #include <libssh2.h>
 
@@ -342,7 +342,7 @@ static int _git_ssh_authenticate_session(
 				session, c->username, c->prompt_callback);
 			break;
 		}
-#ifdef GIT_SSH_MEMORY_CREDENTIALS
+#ifdef GIT_SSH_LIBSSH2_MEMORY_CREDENTIALS
 		case GIT_CREDENTIAL_SSH_MEMORY: {
 			git_credential_ssh_key *c = (git_credential_ssh_key *)cred;
 
@@ -1020,7 +1020,7 @@ static int list_auth_methods(int *out, LIBSSH2_SESSION *session, const char *use
 		if (!git__prefixcmp(ptr, SSH_AUTH_PUBLICKEY)) {
 			*out |= GIT_CREDENTIAL_SSH_KEY;
 			*out |= GIT_CREDENTIAL_SSH_CUSTOM;
-#ifdef GIT_SSH_MEMORY_CREDENTIALS
+#ifdef GIT_SSH_LIBSSH2_MEMORY_CREDENTIALS
 			*out |= GIT_CREDENTIAL_SSH_MEMORY;
 #endif
 			ptr += strlen(SSH_AUTH_PUBLICKEY);

src/util/git2_features.h.in

@@ -30,7 +30,8 @@
 #cmakedefine GIT_QSORT_MSC
 
 #cmakedefine GIT_SSH 1
-#cmakedefine GIT_SSH_MEMORY_CREDENTIALS 1
+#cmakedefine GIT_SSH_LIBSSH2 1
+#cmakedefine GIT_SSH_LIBSSH2_MEMORY_CREDENTIALS 1
 
 #cmakedefine GIT_NTLM 1
 #cmakedefine GIT_GSSAPI 1

tests/libgit2/online/clone.c

@@ -675,7 +675,7 @@ void test_online_clone__ssh_auth_methods(void)
  */
 void test_online_clone__ssh_certcheck_accepts_unknown(void)
 {
-#if !defined(GIT_SSH) || !defined(GIT_SSH_MEMORY_CREDENTIALS)
+#if !defined(GIT_SSH_LIBSSH2) || !defined(GIT_SSH_MEMORY_CREDENTIALS)
 	clar__skip();
 #endif
 
@@ -793,7 +793,7 @@ static int cred_foo_bar(git_credential **cred, const char *url, const char *user
 
 void test_online_clone__ssh_cannot_change_username(void)
 {
-#ifndef GIT_SSH
+#ifndef GIT_SSH_LIBSSH2
 	clar__skip();
 #endif
 	g_options.fetch_opts.callbacks.credentials = cred_foo_bar;