Compress binaries and use xz-embedded in magiskinit

build.py

@@ -106,6 +106,9 @@ def execv(cmd, redirect=None):
 def system(cmd, redirect=None):
 	return subprocess.run(cmd, shell=True, stdout=redirect if redirect != None else STDOUT)
 
+def xz(data):
+	return lzma.compress(data, preset=9, check=lzma.CHECK_NONE)
+
 def sign_zip(unsigned, output, release):
 	signer_name = 'zipsigner-3.0.jar'
 	zipsigner = os.path.join('utils', 'build', 'libs', signer_name)
@@ -151,7 +154,7 @@ def sign_apk(source, target):
 
 def binary_dump(src, out, var_name):
 	out.write('const static unsigned char {}[] = {{'.format(var_name))
-	for i, c in enumerate(src.read()):
+	for i, c in enumerate(xz(src.read())):
 		if i % 16 == 0:
 			out.write('\n')
 		out.write('0x{:02X},'.format(c))
@@ -173,11 +176,11 @@ def gen_update_binary():
 	binary = os.path.join('native', 'out', 'armeabi-v7a', 'busybox')
 	with open(binary, 'rb') as busybox:
 		update_bin.append('\'\nBB_ARM=')
-		update_bin.append(base64.b64encode(lzma.compress(busybox.read(), preset=9, check=lzma.CHECK_NONE)).decode('ascii'))
+		update_bin.append(base64.b64encode(xz(busybox.read())).decode('ascii'))
 	binary = os.path.join('native', 'out', 'x86', 'busybox')
 	with open(binary, 'rb') as busybox:
 		update_bin.append('\nBB_X86=')
-		update_bin.append(base64.b64encode(lzma.compress(busybox.read(), preset=9, check=lzma.CHECK_NONE)).decode('ascii'))
+		update_bin.append(base64.b64encode(xz(busybox.read())).decode('ascii'))
 		update_bin.append('\n')
 	with open(os.path.join('scripts', 'update_binary.sh'), 'r') as script:
 		update_bin.append(script.read())
@@ -213,7 +216,7 @@ def build_binary(args):
 			bin_file = os.path.join('native', 'out', arch, 'magisk')
 			with open(os.path.join('native', 'out', arch, 'binaries_arch.h'), 'w') as out:
 				with open(bin_file, 'rb') as src:
-					binary_dump(src, out, 'magisk_bin')
+					binary_dump(src, out, 'magisk_xz')
 
 	old_plat = False
 	flags = base_flags
@@ -280,7 +283,7 @@ def build_apk(args):
 		mkdir(os.path.join('native', 'out'))
 		with open(os.path.join('native', 'out', 'binaries.h'), 'w') as out:
 			with open(release, 'rb') as src:
-				binary_dump(src, out, 'manager_bin');
+				binary_dump(src, out, 'manager_xz');
 	else:
 		proc = execv([gradlew, 'app:assembleDebug'])
 		if proc.returncode != 0:

native/jni/Android.mk

@@ -67,10 +67,11 @@ ifdef B_INIT
 # magiskinit
 include $(CLEAR_VARS)
 LOCAL_MODULE := magiskinit
-LOCAL_STATIC_LIBRARIES := libsepol
+LOCAL_STATIC_LIBRARIES := libsepol libxz
 LOCAL_C_INCLUDES := \
 	jni/include \
 	jni/magiskpolicy \
+	$(EXT_PATH)/include \
 	out \
 	out/$(TARGET_ARCH_ABI) \
 	$(LIBSEPOL)

native/jni/b64xz.c

@@ -22,7 +22,7 @@ static void decodeblock(uint8_t* in, uint8_t* out) {
 	out[2] = (uint8_t)(((in[2] << 6) & 0xc0) | in[3]);
 }
 
-static int unxz(struct xz_dec *dec, void *buf, unsigned size) {
+static int unxz(struct xz_dec *dec, const void *buf, unsigned size) {
 	uint8_t out[8192];
 	struct xz_buf b = {
 			.in = buf,

native/jni/core/magiskinit.c

@@ -36,6 +36,8 @@
 #include <sys/sendfile.h>
 #include <sys/sysmacros.h>
 
+#include <xz.h>
+
 #include "binaries.h"
 #include "binaries_arch.h"
 
@@ -243,16 +245,38 @@ static int patch_sepolicy() {
 	return 0;
 }
 
+static int unxz(int fd, const void *buf, size_t size) {
+	uint8_t out[8192];
+	struct xz_dec *dec = xz_dec_init(XZ_DYNALLOC, 1 << 26);
+	struct xz_buf b = {
+			.in = buf,
+			.in_pos = 0,
+			.in_size = size,
+			.out = out,
+			.out_pos = 0,
+			.out_size = sizeof(out)
+	};
+	enum xz_ret ret;
+	do {
+		ret = xz_dec_run(dec, &b);
+		if (ret != XZ_OK && ret != XZ_STREAM_END)
+			return 1;
+		write(fd, out, b.out_pos);
+		b.out_pos = 0;
+	} while (b.in_pos != size);
+	return 0;
+}
+
 static int dump_magisk(const char *path, mode_t mode) {
 	int fd = creat(path, mode);
-	xwrite(fd, magisk_bin, sizeof(magisk_bin));
+	unxz(fd, magisk_xz, sizeof(magisk_xz));
 	close(fd);
 	return 0;
 }
 
 static int dump_manager(const char *path, mode_t mode) {
 	int fd = creat(path, mode);
-	xwrite(fd, manager_bin, sizeof(manager_bin));
+	unxz(fd, manager_xz, sizeof(manager_xz));
 	close(fd);
 	return 0;
 }