GDB and Gdbserver debug Android app with executable

Learn android5.0 after the art virtual machine, looked at the source code, compared to the headache, decided by the dynamic debugging way to learn.

The art virtual machine has a dex2oat executable program. I thought of debugging this dex2oat through GDB and Gdbserver.

Record the Debugging method:

GDB runs on the Local System (Windows/linux)

Gdbserver run on Android real/emulator (adb shell Ls/system/bin to see if there are gdbserver, if not, can be obtained from the source Code Prebuild folder, or it can be obtained from the NDK file)

The PS:GDB and Gdbserver versions are consistent, or they will go wrong.

One: "

1. Preparation work :

1-1. Find the GDB and Gdbserver executables in the Prebuild folder (also available in the NDK)

1-2, put gdbserver through adb shell push into system/bin

1-3, push the Hello.jar needed by Dex2oat to/data/test/.

2, through the ADB in the Android emulator through the Gdbserver association related processes or start related processes

2-1,gdbserver Associated processes: adb shell gdbserver: Port number 1234--attach process PID

(Process PID can be attach system_process (without testing) through ADB shell, debug application)

2-2,gdbserver Start related process: adb shell gdbserver: port number 1234 Dex2oat--dex-file=/data/test/hello.jar--oat-file=/data/ Test/hello.dex

3, Port mapping :

On the local command line: adb forward tcp:1234 tcp:1234

4, start gdb in the directory where GDB is located

4-1,cd/home/zero/android-5.0.0_r3.0.1/prebuilts/gcc/linux-x86/arm/arm-linux-androideabi-4.8/bin

4-2,./arm-linux-androideabi-gdb

5, after entering GDB:

5-1, (GDB) target remote localhost:1234 (connection target)

5-2, (GDB) file/home/zero/android-5.0.0_r3.0.1/out/target/product/generic/symbols/system/bin/dex2oat (Find executable file dex2oat, all in the Android source of this bin directory)

5-3, (GDB) set Solib-absolute-prefix/home/zero/android-5.0.0_r3.0.1/out/target/product/generic/symbols (do not understand why this sentence)

5-4, (GDB) Set Solib-search-path/home/zero/android-5.0.0_r3.0.1/out/target/product/generic/symbols/system/lib (Set the function path?? ）

6, set breakpoints, start execution

6-1, (GDB) b main

6-2, (GDB) c

II: Gdbclient and GDB

1, execute in Source directory:

1-1,source build/envsetup.sh

1-2,lunch Full-eng

2, similar to the above Gdbserver's boot and adb forward port mappings

3, Start gdbclient

Gdbclient dex2oat:1234

4, set breakpoints, start debugging

Source code for Gdbclient in envsetup.sh

<span style= "FONT-SIZE:18PX;" ># Gdbclient now determines whether the user wants to debug a 32-bit or 64-bit# executable, set up the approriate gdbse RVer, then invokes the proper host# gdb.function gdbclient () {local out_root=$ (Get_abs_build_var product_out) Local OU t_symbols=$ (Get_abs_build_var target_out_unstripped) Local out_so_symbols=$ (Get_abs_build_var TARGET_OUT_SHARED_ libraries_unstripped) Local out_vendor_so_symbols=$ (Get_abs_build_var Target_out_vendor_shared_libraries_ unstripped) Local out_exe_symbols=$ (get_symbols_directory) Local prebuilts=$ (Get_abs_build_var ANDROID_PREBUILTS) Lo       Cal arch=$ (Get_build_var target_arch) Local GDB case "$ARCH" in arm) gdb=arm-linux-androideabi-gdb;; arm64) Gdb=arm-linux-androideabi-gdb;       Gdb64=aarch64-linux-android-gdb;;       MIPS|MIPS64) gdb=mips64el-linux-android-gdb;;       x86) Gdb=x86_64-linux-android-gdb;;       x86_64) gdb=x86_64-linux-android-gdb;; *) echo "Unknown arch $ARCH";   return 1;; Esac   #参数1 <span style= "White-space:pre" ></span> if ["$OUT _root"-A "$PREBUILTS"]; Then local exe= "$" if ["$EXE"]; Then exe=$1 if [[$EXE =~ ^[^/].*]; Then exe= "system/bin/" $EXE fi else exe= "app_process" fi #参数2 <span S Tyle= "White-space:pre" ></span> local port= "$" if ["$PORT"]; Then port=$2 else port= ": 5039" fi local pid= "$" if ["$PID"]; Then if [[! "$PID" =~ ^[0-9]+$]]; Then pid= ' PID $ ' if [[! "$PID" =~ ^[0-9]+$]]; Then # this likely didn ' t work because of returning multiple processes # try again, fi Ltering by root processes (don ' t contain colon) pid= ' adb shell PS | \grep | \grep-v ":" | awk ' {print $} ' if [[! "$PID" =~ ^[0-9]+$]] then echo "couldn' t resolve ' to a single PID return 1 else Echo '                    echo "Warning:multiple processes matching ' $ ' observed, using root process" echo " Fi fi fi adb Forward "tcp$port" "tcp$port" local use64bit= "               $ (is64bit $PID) "adb shell gdbserver$use64bit $PORT--attach $PID & Sleep 2 Else echo "echo" If you haven ' t did so already, does this first on the device: "Echo" Gdbse               RVer $PORT/system/bin/$EXE "echo" or "echo" Gdbserver $PORT--attach <PID> " echo "" Fi out_so_symbols= $OUT _so_symbols$use64bit out_vendor_so_symbols= $OUT _vendor_so_symb Ols$use64bit echo >| " $OUT _root/gdbclient.cmds "" Set Solib-absolute-prefix $OUT _symbols "echo >> $OUT _root/gdbclient.cmds" "SeT Solib-search-path $OUT _so_symbols: $OUT _so_symbols/hw: $OUT _so_symbols/ssl/engines: $OUT _so_symbols/drm: $OUT _so_ SYMBOLS/EGL: $OUT _so_symbols/soundfx: $OUT _vendor_so_symbols: $OUT _vendor_so_symbols/hw: $OUT _vendor_so_symbols/ EGL "Echo >>" $OUT _root/gdbclient.cmds "" Source $ANDROID _build_top/development/scripts/gdb/dalvik.gdb "EC       Ho >> "$OUT _root/gdbclient.cmds" "Target remote $PORT" # Enable Special Debugging for ART processes. if [[$EXE =~ (^|/) (APP_PROCESS|DALVIKVM) (|32|64) $]];       Then echo >> "$OUT _root/gdbclient.cmds" "art-on" fi echo >> "$OUT _root/gdbclient.cmds" "" Local which_gdb= # 64-bit EXE found if ["$USE 64BIT"! = ""]; Then which_gdb= $ANDROID _toolchain/$GDB # 32-bit exe/32-bit platform Elif ["$ (Get_build_var Targ Et_2nd_arch) "=" "]; Then which_gdb= $ANDROID _toolchain/$GDB # 32-bit exe/64-bit platform Else which_gdb= $ANDR oid_toolchain_2nd_arch/$GDB fi gdbwrapper $WHICH _gdb "$OUT _root/gdbclient.cmds" "$OUT _exe_symbols/$EXE" Else echo "unabl   E to determine build system output dir. " Fi}</span>

GDB and Gdbserver debug Android app with executable