NDK debugging: ndk-gdb fails to pull app_process. Who and when creates the app_process binary?

问题

While investigating a problem with hitting breakpoints in native code, I decided to check if ndk-gdb works OK. I've deleted app_process, started Java debugging and ran ndk-gdb --force. Guess what, app_process is not created. ndk-gdb --verbose output has this line :

## COMMAND: adb_cmd pull /system/bin/app_process obj/local/armeabi-v7a/app_process
remote object '/system/bin/app_process' not a file or directory
Pulled app_process from device/emulator.

I've uninstalled the app from the target device, rebooted the device and repeated. Still no app_process. So, I wonder what's the problem here, and I also wonder when is this file created, and by what process / script.

回答1:

As mentioned before, Android 5.0 has /system/bin/app_process as a symlink to /system/bin/app_process32. Since a symlink cannot be pulled with adb pull, the ndk-gdb script will not be able to work as-is.

Change ndk-gdb as follows to support api21 changes as well as backwards compatibility for < api21:

# Get the app_server binary from the device
APP_PROCESS=$APP_OUT/app_process
if [ "$API_LEVEL" -lt "21" ] ; then
    run adb_cmd pull /system/bin/app_process `native_path $APP_PROCESS`
    log "Pulled app_process from device/emulator to $APP_PROCESS"
else
    run adb_cmd pull /system/bin/app_process32 `native_path $APP_PROCESS`
    log "Pulled app_process32 from device/emulator to $APP_PROCESS"
fi

EDIT: or:

# Get the app_server binary from the device
APP_PROCESS=$APP_OUT/app_process
APP_PROCESS_DEVICE=app_process32
if [ "$API_LEVEL" -lt "21" ] ; then
    APP_PROCESS_DEVICE=app_process
fi
run adb_cmd pull /system/bin/$APP_PROCESS_DEVICE `native_path $APP_PROCESS`
log "Pulled $APP_PROCESS_DEVICE from device/emulator to $APP_PROCESS"

Original Change is also here: http://pastebin.com/YfxNs06U. Note that this change renames app_process32 to app_process when it is pulled to your development machine to support having a single debugging config in Eclipse.

回答2:

Found the problem. My device is running Android 5.0 preview, and app_process there is a symlink to a file called app_process32. So pulling app_process32 works fine.

回答3:

In addition to the answer of Violet Giraffe, exchange in the script ndk-gdb the line

run adb_cmd pull /system/bin/app_process `native_path $APP_PROCESS`

with

run adb_cmd pull /system/bin/app_process32 `native_path $APP_PROCESS`

This solved the problem for me for this Android 5.0 issue and I was able to build and debug as before.

来源：https://stackoverflow.com/questions/26530675/ndk-debugging-ndk-gdb-fails-to-pull-app-process-who-and-when-creates-the-app-p

标签

android

windows

debugging

android-ndk

eclipse-adt