Refer to github: https://github.com/bonnyfone/adb-arm

The original purpose was to get shell privileges using adb shell after the arm platform compiled, and then avoid the problem that other privileges could not execute su.

At first, I modified the su.c in the android source code, commented out the root and shell permission validation part, compiled it, or not. There will be errors in setgid and setuid. This error tormented me for two days, but I have to find another way.

Suddenly it occurred to me that adb has shell privileges, and can compile adb as a dynamic library by itself and call android application through jni mode, so that it can have root privileges on mobile phones that already have root privileges (without root platform, we need to study how to root again). At present, this method has not been verified.

Provide ADB compilation method (this method is only compiling the executable file adb, can be modified to dynamic library mode on this basis, this way is relatively simple, not explained here):

The compiled version is: android-4.4.4_r2.0.1

The download of the source code needs a ladder...

The script file:

#         CONFIG
# -------------------------

# Branch to checkout from Android source code repo
branch=android-4.4.4_r2.0.1

# Makefile to use (will be automatically copied into system/core/adb)
makefile=makefile.sample


# DOWNLOAD necessary files
# -------------------------
echo "\n>> >>> ADB for ARM <<< \n"
echo "\n>> Downloading necessay files ($branch branch)\n"
mkdir android-adb
cd android-adb
mkdir system
cd system
git clone -b $branch https://android.googlesource.com/platform/system/core
git clone -b $branch https://android.googlesource.com/platform/system/extras
cd ..
mkdir external
cd external
git clone -b $branch https://android.googlesource.com/platform/external/zlib
git clone -b $branch https://android.googlesource.com/platform/external/openssl
git clone -b $branch https://android.googlesource.com/platform/external/libselinux
cd ..


# MAKE
# -------------------------
echo "\n>> Copying makefile into system/core/adb...\n"
cp ../$makefile system/core/adb/makefile -f
cd system/core/adb/
echo "\n>> Make... \n"
make clean
make
echo "\n>> Copying adb back into current dir...\n"
cp adb ../../../../
echo "\n>> FINISH!\n"

makefile.example file:

# ADB makefile
# ------------

#TODO change TOOLCHAIN variable to your toolchain path 
#TOOLCHAIN= /opt/poky/1.5/sysroots/x86_64-pokysdk-linux/usr/bin/arm-poky-linux-gnueabi/arm-poky-linux-gnueabi-
TOOLCHAIN = /home/linux/bin/android-toolchain/bin/arm-linux-androideabi-
CC = $(TOOLCHAIN)gcc
LD = $(TOOLCHAIN)gcc
CXX = $(CC)

SRCS += adb.c
SRCS += fdevent.c
SRCS += adb_client.c
SRCS += commandline.c
SRCS += console.c
SRCS += file_sync_client.c
SRCS += get_my_path_linux.c
SRCS += services.c
SRCS += sockets.c
SRCS += transport.c
SRCS += transport_local.c
SRCS += transport_usb.c
SRCS += usb_linux.c
SRCS += usb_vendors.c
SRCS += adb_auth_host.c
 
VPATH += ../libcutils
SRCS += list.c
SRCS += socket_inaddr_any_server.c
SRCS += socket_local_client.c
SRCS += socket_local_server.c
SRCS += socket_loopback_client.c
SRCS += socket_loopback_server.c
SRCS += socket_network_client.c
SRCS += load_file.c
 
VPATH += ../libzipfile
SRCS += centraldir.c
SRCS += zipfile.c
 
VPATH += ../../../external/zlib/src
SRCS += adler32.c
SRCS += compress.c
SRCS += crc32.c
SRCS += deflate.c
SRCS += infback.c
SRCS += inffast.c
SRCS += inflate.c
SRCS += inftrees.c
SRCS += trees.c
SRCS += uncompr.c
SRCS += zutil.c

CPPFLAGS += -DADB_HOST=1
CPPFLAGS += -DHAVE_FORKEXEC=1
CPPFLAGS += -DHAVE_SYMLINKS
CPPFLAGS += -DHAVE_TERMIO_H
CPPFLAGS += -DHAVE_SYS_SOCKET_H
CPPFLAGS += -D_GNU_SOURCE
CPPFLAGS += -D_XOPEN_SOURCE
CPPFLAGS += -std=c++11 
CPPFLAGS += -I.
CPPFLAGS += -I../include
CPPFLAGS += -I../../../external/zlib
CPPFLAGS += -I../../../external/openssl/include
CPPFLAGS += -I../base/include 
CFLAGS += -O2 -g -Wall -Wno-unused-parameter

LIBS = -lcrypto -pthread -fPIE -pie
#LIBS += -lrt

OBJS = $(SRCS:.c=.o)

all: adb

adb: $(OBJS)
	$(LD) -o $@ $(LDFLAGS) $(OBJS) $(LIBS)

clean:
	rm -rf $(OBJS)

TOOLCHAIN is a local ndk tool chain, extracted from r9.

You can manually download the source code in the script, and then put the makefile directly under ~/system/core/adb/. Executing make can generate the ADB file, verifying that there is no problem. Dynamic libraries haven't been compiled yet.