init.patch

Subject: [PATCH] init: Add support for kernels that don't have finit_module

Some kernels don't have finit_module, which makes booting Android 7.0
impossible if people can't backport it themselves, so set 
KERNEL_HAS_FINIT_MODULE := false in BoardConfig.mk file to
allow booting 7.0 even when the kernel doesn't have finit_
module :)

diff --git a/init/Android.mk b/init/Android.mk
index a19b158..d66ac5a 100644
--- a/init/Android.mk
+++ b/init/Android.mk
@@ -95,6 +95,10 @@
     watchdogd.cpp \
     vendor_init.cpp
 
+ifeq ($(KERNEL_HAS_FINIT_MODULE), false)
+LOCAL_CFLAGS += -DNO_FINIT_MODULE
+endif
+
 LOCAL_MODULE:= init
 LOCAL_C_INCLUDES += \
     system/core/mkbootimg
diff --git a/init/builtins.cpp b/init/builtins.cpp
index 1df4e91..10c4bb9 100755
--- a/init/builtins.cpp
+++ b/init/builtins.cpp
@@ -29,7 +29,9 @@
 #include <sys/socket.h>
 #include <sys/mount.h>
 #include <sys/resource.h>
+#ifndef NO_FINIT_MODULE
 #include <sys/syscall.h>
+#endif
 #include <sys/time.h>
 #include <sys/types.h>
 #include <sys/stat.h>
@@ -73,20 +75,34 @@
 
 #define chmod DO_NOT_USE_CHMOD_USE_FCHMODAT_SYMLINK_NOFOLLOW
 
+#ifdef NO_FINIT_MODULE
+// System call provided by bionic but not in any header file.
+extern "C" int init_module(void *, unsigned long, const char *);
+#endif
+
 static constexpr std::chrono::nanoseconds kCommandRetryTimeout = 5s;
 
 static int insmod(const char *filename, const char *options, int flags) {
+#ifndef NO_FINIT_MODULE
     int fd = open(filename, O_RDONLY | O_NOFOLLOW | O_CLOEXEC);
     if (fd == -1) {
         PLOG(ERROR) << "insmod: open(\"" << filename << "\") failed";
+#else
+    std::string module;
+    if (!read_file(filename, &module)) {
+#endif
         return -1;
     }
+#ifndef NO_FINIT_MODULE
     int rc = syscall(__NR_finit_module, fd, options, flags);
     if (rc == -1) {
         PLOG(ERROR) << "finit_module for \"" << filename << "\" failed";
     }
     close(fd);
     return rc;
+#else
+    return init_module(&module[0], module.size(), options);
+#endif
 }
 
 static int __ifupdown(const char *interface, int up) {