MarcoBuster/Magisk
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Use external functions in init

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Don't reinvent the wheel
This commit is contained in:
topjohnwu 2017-09-15 03:22:23 +08:00
parent e5e34797a8
commit 8c8a63ebfb
2 changed files with 16 additions and 28 deletions
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6
jni/Android.mk
View File

@ -94,7 +94,11 @@ include $(BUILD_EXECUTABLE)
ifeq ($(TARGET_ARCH_ABI), arm64-v8a)
include $(CLEAR_VARS)
LOCAL_MODULE := magiskinit
LOCAL_SRC_FILES := magiskinit.c
LOCAL_C_INCLUDES := jni/include
LOCAL_SRC_FILES := \
magiskinit.c \
magiskboot/boot_utils.c \
utils/xwrap.c
LOCAL_LDFLAGS := -static
include $(BUILD_EXECUTABLE)
endif

38
jni/magiskinit.c
View File

@ -10,6 +10,7 @@
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <dirent.h>
@ -34,21 +35,9 @@ struct device {
char path[64];
};
static void mmap_ro(const char *filename, void **buf, size_t *size) {
int fd = open(filename, O_RDONLY);
*size = lseek(fd, 0, SEEK_END);
lseek(fd, 0, SEEK_SET);
*buf = mmap(NULL, *size, PROT_READ, MAP_SHARED, fd, 0);
close(fd);
}
static void mmap_rw(const char *filename, void **buf, size_t *size) {
int fd = open(filename, O_RDWR);
*size = lseek(fd, 0, SEEK_END);
lseek(fd, 0, SEEK_SET);
*buf = mmap(NULL, *size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
close(fd);
}
extern void mmap_ro(const char *filename, void **buf, size_t *size);
extern void mmap_rw(const char *filename, void **buf, size_t *size);
extern void *patch_init_rc(char *data, uint32_t *size);
static void clone_dir(int src, int dest) {
struct dirent *entry;
@ -245,19 +234,14 @@ static void patch_ramdisk() {
}
}
munmap(addr, size);
mmap_ro("/init.rc", &addr, &size);
int fd = open("/init.rc.patch", O_WRONLY | O_CREAT | O_CLOEXEC, 0750);
for (int i = 0; i < size; ++i) {
if (memcmp(addr + i, "import", 6) == 0) {
write(fd, addr, i);
write(fd, "import /init.magisk.rc\n", 23);
write(fd, addr + i, size -i);
close(fd);
break;
}
}
mmap_rw("/init.rc", &addr, &size);
uint32_t new_size = size;
void *init_rc = patch_init_rc(addr, &new_size);
munmap(addr, size);
rename("/init.rc.patch", "/init.rc");
int fd = open("/init.rc", O_WRONLY | O_TRUNC | O_CLOEXEC);
write(fd, init_rc, new_size);
close(fd);
free(init_rc);
}
int main(int argc, char *argv[]) {