diff --git a/jni/magiskinit.c b/jni/magiskinit.c index 621d03819..2dd918c8f 100644 --- a/jni/magiskinit.c +++ b/jni/magiskinit.c @@ -6,6 +6,7 @@ #include #include #include +#include #include #include @@ -22,6 +23,22 @@ 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); +} + static void clone_dir(int src, int dest) { struct dirent *entry; DIR *dir; @@ -206,6 +223,32 @@ static int setup_block(struct device *dev, const char *partname) { return 0; } +static void patch_ramdisk() { + void *addr; + size_t size; + mmap_rw("/init", &addr, &size); + for (int i = 0; i < size; ++i) { + if (memcmp(addr + i, "/system/etc/selinux/plat_sepolicy.cil", 37) == 0) { + memcpy(addr + i, "/system/etc/selinux/plat_sepolicy.xxx", 37); + break; + } + } + 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; + } + } + munmap(addr, size); + rename("/init.rc.patch", "/init.rc"); +} + int main(int argc, char *argv[]) { umask(0); @@ -234,6 +277,8 @@ int main(int argc, char *argv[]) { if (overlay > 0) mv_dir(overlay, root); + patch_ramdisk(); + close(root); close(system_root); close(overlay);