sof-remote-server

sof-remote-server & sof-remote

Lightweight C TCP telemetry, IPC, LLEXT, mixer, and audio debug daemon (sof_remote_server, default TCP port 9998) and CLI client (sof-remote) for Linux and Android SOF targets.

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Building for Linux

# From top-level sof-utils/
make remote-server

# Or directly in sof-remote-server/
make -C sof-remote-server

Install dependencies on Debian/Ubuntu if building with ALSA/TinyALSA/TinyCompress:

sudo apt install libasound2-dev

CMake (Linux)

cmake -B sof-remote-server/build -S sof-remote-server
cmake --build sof-remote-server/build -j$(nproc)

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Building for Android

sof-remote-server supports three Android build workflows using Bionic + NO_ALSA + TinyALSA + TinyCompress (<tinyalsa/asoundlib.h> or <tinyalsa/pcm.h>/mixer.h).

1. Standalone make android (Android NDK or AOSP Tree)

With Android NDK

export ANDROID_NDK_HOME=/path/to/android-ndk

# Default (x86_64, API 34)
make android

# ARM64
make android ANDROID_ABI=arm64-v8a ANDROID_API=34

With an AOSP Checkout

When AOSP_DIR is set (and ANDROID_NDK_HOME is unset), the Makefile automatically discovers the prebuilt Clang toolchain, Soong NDK sysroot (out/soong/ndk/sysroot), Soong Bionic CRT objects (crtbegin_dynamic.o / crtend_android.o mapped via ANDROID_SOONG_ARCH: arm64, arm, x86, x86_64), and external/tinyalsa + external/tinycompress:

make android AOSP_DIR=/path/to/aosp ANDROID_ABI=x86_64 ANDROID_API=34
make android AOSP_DIR=/path/to/aosp ANDROID_ABI=arm64-v8a ANDROID_API=34

Output binaries are written to sof-remote-server/build-android-<ANDROID_ABI>/ (sof_remote_server and sof-remote).

Push & Run Over ADB

make android-push ANDROID_ABI=arm64-v8a
adb shell /data/local/tmp/sof_remote_server -p 9998

android-push pushes both binaries to /data/local/tmp/ and runs adb forward tcp:9998 tcp:9998.

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2. CMake with Android NDK Toolchain

cmake -B sof-remote-server/build-android-cmake \
  -S sof-remote-server \
  -DCMAKE_TOOLCHAIN_FILE=$ANDROID_NDK_HOME/build/cmake/android.toolchain.cmake \
  -DANDROID_ABI=arm64-v8a \
  -DANDROID_PLATFORM=android-34
cmake --build sof-remote-server/build-android-cmake -j$(nproc)

Optional TinyALSA / TinyCompress CMake variables:

• -DTINYALSA_INC=/path/to/tinyalsa/include and -DTINYALSA_LIB=/path/to/libtinyalsa.so
• -DTINYCOMPRESS_INC=/path/to/tinycompress/include and -DTINYCOMPRESS_LIB=/path/to/libtinycompress.so

(On ANDROID, CMake automatically omits -lpthread since pthreads are integrated into Bionic libc.)

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3. In-Tree AOSP Soong Build (Android.bp)

Place or vendor-map sof-remote-server/ inside the AOSP source tree and build directly with Soong:

m sof_remote_server sof-remote

Android.bp builds vendor-proprietary targets linking libtinyalsa, libtinycompress, and liblog.

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Runtime Options & Android Security Model

sof_remote_server [-b <bind_ip>] [-d /dev/sof-dsp0] [-p 9998] [-D] [-E|-S]

Flag	Default (Linux)	Default (Android)	Description
-b <addr>	0.0.0.0	127.0.0.1	IPv4 bind address. Android defaults to loopback for use with adb forward tcp:9998 tcp:9998.
-d <dev>	/dev/sof-dsp0	/dev/sof-dsp0	SOF character device path (falls back to DebugFS/SysFS + TinyALSA when absent).
-p <port>	9998	9998	TCP listening port.
-D	off	off	Daemonize (fork to background).
-E / -S	-E (enabled)	-S (disabled)	Enable (-E) or disable (-S) host: shell command execution (SOF_NET_OP_SHELL_EXEC via popen()).

Android Init Service (sof_remote_server.rc)

sof_remote_server.rc defines vendor.sof_remote_server (disabled by default), binding 127.0.0.1:9998 without host: shell execution, and starts only when both ro.debuggable=1 and the explicit opt-in property are set:

adb shell setprop persist.vendor.sof.remote_server.enable 1   # start
adb shell setprop persist.vendor.sof.remote_server.enable 0   # stop
adb forward tcp:9998 tcp:9998

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Reference SELinux Policy (sepolicy/)

A reference vendor policy for userdebug / eng builds is provided in sepolicy/:

• sepolicy/file_contexts (/vendor/bin/sof_remote_server)
• sepolicy/property.te & sepolicy/property_contexts (persist.vendor.sof.remote_server.enable)
• sepolicy/sof_remote_server.te (wrapped in userdebug_or_eng(...))

Include it in a device BoardConfig.mk:

BOARD_VENDOR_SEPOLICY_DIRS += <path-to-sof-utils>/sof-remote-server/sepolicy

If your kernel/product exposes a dedicated /dev/sof-dsp0 character device node under SELinux enforcing mode, add a product file_contexts device label and corresponding rw_file_perms allow rule for sof_remote_server.