Merge branch 'topjohnwu:master' into master

.gitmodules

@@ -34,6 +34,9 @@
 [submodule "system_properties"]
 	path = native/src/external/system_properties
 	url = https://github.com/topjohnwu/system_properties.git
+[submodule "crt0"]
+	path = native/src/external/crt0
+	url = https://github.com/topjohnwu/crt0.git
 [submodule "termux-elf-cleaner"]
 	path = tools/termux-elf-cleaner
 	url = https://github.com/termux/termux-elf-cleaner.git

build.py

@@ -421,6 +421,7 @@ def build_binary(args):
 
     if "magiskinit" in args.target:
         flag += " B_INIT=1"
+        flag += " B_CRT0=1"
 
     if flag:
         dump_bin_header(args)
@@ -555,27 +556,6 @@ def setup_ndk(args):
     rm_rf(ndk_path)
     mv(ondk_path, ndk_path)
 
-    header("* Patching static libs")
-    for target in ["arm-linux-androideabi", "i686-linux-android"]:
-        arch = target.split("-")[0]
-        lib_dir = op.join(
-            ndk_path,
-            "toolchains",
-            "llvm",
-            "prebuilt",
-            f"{os_name}-x86_64",
-            "sysroot",
-            "usr",
-            "lib",
-            f"{target}",
-            "23",
-        )
-        if not op.exists(lib_dir):
-            continue
-        src_dir = op.join("tools", "ndk-bins", arch)
-        rm(op.join(src_dir, ".DS_Store"))
-        shutil.copytree(src_dir, lib_dir, copy_function=cp, dirs_exist_ok=True)
-
 
 def push_files(args, script):
     abi = cmd_out([adb_path, "shell", "getprop", "ro.product.cpu.abi"])

native/src/Android.mk

@@ -63,7 +63,6 @@ include $(CLEAR_VARS)
 LOCAL_MODULE := magiskinit
 LOCAL_STATIC_LIBRARIES := \
     libbase \
-    libcompat \
     libpolicy \
     libxz \
     libinit-rs
@@ -77,6 +76,13 @@ LOCAL_SRC_FILES := \
     init/selinux.cpp \
     init/init-rs.cpp
 
+LOCAL_LDFLAGS := -static -T src/lto_fix.lds
+
+ifdef B_CRT0
+LOCAL_STATIC_LIBRARIES += crt0
+LOCAL_LDFLAGS :=
+endif
+
 include $(BUILD_EXECUTABLE)
 
 endif
@@ -87,7 +93,6 @@ include $(CLEAR_VARS)
 LOCAL_MODULE := magiskboot
 LOCAL_STATIC_LIBRARIES := \
     libbase \
-    libcompat \
     liblzma \
     liblz4 \
     libbz2 \
@@ -102,6 +107,8 @@ LOCAL_SRC_FILES := \
     boot/format.cpp \
     boot/boot-rs.cpp
 
+LOCAL_LDFLAGS := -static -T src/lto_fix.lds
+
 include $(BUILD_EXECUTABLE)
 
 endif

native/src/Application.mk

@@ -8,6 +8,15 @@ APP_PLATFORM     := android-23
 APP_THIN_ARCHIVE := true
 APP_STRIP_MODE   := none
 
+ifdef B_CRT0
+
+# Disable all security and debugging features
+APP_CFLAGS       +=	-fno-unwind-tables -fno-asynchronous-unwind-tables -fno-stack-protector -U_FORTIFY_SOURCE
+# Override output folder to make sure all dependencies are rebuilt with new CFLAGS
+NDK_APP_OUT      := ./obj/nolibc
+
+endif
+
 # Busybox should use stock libc.a
 ifdef B_BB
 APP_PLATFORM     := android-26

native/src/base/Android.mk

@@ -22,18 +22,3 @@ LOCAL_SRC_FILES := \
     base-rs.cpp \
     ../external/cxx-rs/src/cxx.cc
 include $(BUILD_STATIC_LIBRARY)
-
-# All static executables should link with libcompat
-
-include $(CLEAR_VARS)
-LOCAL_MODULE := libcompat
-LOCAL_SRC_FILES := compat/compat.cpp
-# Fix static variables' ctor/dtor when using LTO
-# See: https://github.com/android/ndk/issues/1461
-LOCAL_EXPORT_LDFLAGS := -static -T src/lto_fix.lds -Wl,--wrap=rename -Wl,--wrap=renameat
-# For some reason, using the hacky libc.a with x86 will trigger stack protection violation
-# when mixing Rust and C++ code. Disable stack protector to bypass this issue.
-ifeq ($(TARGET_ARCH), x86)
-LOCAL_EXPORT_CFLAGS := -fno-stack-protector
-endif
-include $(BUILD_STATIC_LIBRARY)

native/src/base/cstr.rs

@@ -2,9 +2,10 @@ use std::cmp::min;
 use std::ffi::{CStr, FromBytesWithNulError, OsStr};
 use std::fmt::{Arguments, Debug, Display, Formatter, Write};
 use std::ops::{Deref, DerefMut};
-use std::path::Path;
+use std::path::{Path, PathBuf};
 use std::str::{Utf8Chunks, Utf8Error};
 use std::{fmt, mem, slice, str};
+use std::os::unix::ffi::OsStrExt;
 
 use cxx::{type_id, ExternType};
 use libc::c_char;
@@ -105,7 +106,7 @@ trait AsUtf8CStr {
 
 // Implementation for Utf8CString
 
-trait StringExt {
+pub trait StringExt {
     fn nul_terminate(&mut self) -> &mut [u8];
 }
 
@@ -122,6 +123,21 @@ impl StringExt for String {
     }
 }
 
+impl StringExt for PathBuf {
+    #[allow(mutable_transmutes)]
+    fn nul_terminate(&mut self) -> &mut [u8] {
+        self.reserve(1);
+        // SAFETY: the PathBuf is reserved to have enough capacity to fit in the null byte
+        // SAFETY: the null byte is explicitly added outside of the PathBuf's length
+        unsafe {
+            let bytes: &mut [u8] = mem::transmute(self.as_mut_os_str().as_bytes());
+            let buf = slice::from_raw_parts_mut(bytes.as_mut_ptr(), bytes.len() + 1);
+            *buf.get_unchecked_mut(bytes.len()) = b'\0';
+            buf
+        }
+    }
+}
+
 #[derive(Default)]
 pub struct Utf8CString(String);
 

native/src/base/files.cpp

@@ -75,9 +75,14 @@ void file_readline(bool trim, FILE *fp, const function<bool(string_view)> &fn) {
 }
 
 void file_readline(bool trim, const char *file, const function<bool(string_view)> &fn) {
-    if (auto fp = open_file(file, "re"))
-        file_readline(trim, fp.get(), fn);
+    int fd = xopen(file, O_RDONLY | O_CLOEXEC);
+    if (fd >= 0) {
+        auto fp = fdopen(fd, "re");
+        file_readline(trim, fp, fn);
+        fclose(fp);
+    }
 }
+
 void file_readline(const char *file, const function<bool(string_view)> &fn) {
     file_readline(false, file, fn);
 }
@@ -96,8 +101,12 @@ void parse_prop_file(FILE *fp, const function<bool(string_view, string_view)> &f
 }
 
 void parse_prop_file(const char *file, const function<bool(string_view, string_view)> &fn) {
-    if (auto fp = open_file(file, "re"))
-        parse_prop_file(fp.get(), fn);
+    int fd = xopen(file, O_RDONLY | O_CLOEXEC);
+    if (fd >= 0) {
+        auto fp = fdopen(fd, "re");
+        parse_prop_file(fp, fn);
+        fclose(fp);
+    }
 }
 
 std::vector<mount_info> parse_mount_info(const char *pid) {