From 0cc2c5b453f49772b996b36ca08b09e4b90cc8b9 Mon Sep 17 00:00:00 2001 From: Tao Bao Date: Fri, 27 Sep 2019 11:50:43 -0700 Subject: minadbd: Update README.md. Test: N/A Change-Id: I7f4648f2b357de7d9700e38552a0156d13c1bd0b --- minadbd/README.md | 32 ++++++++++++++++++++++++-------- 1 file changed, 24 insertions(+), 8 deletions(-) diff --git a/minadbd/README.md b/minadbd/README.md index 5a0a067de..9a1958309 100644 --- a/minadbd/README.md +++ b/minadbd/README.md @@ -1,8 +1,24 @@ -minadbd is now mostly built from libadbd. The fuse features are unique to -minadbd, and services.c has been modified as follows: - - - all services removed - - all host mode support removed - - `sideload_service()` added; this is the only service supported. It - receives a single blob of data, writes it to a fixed filename, and - makes the process exit. +minadbd +======= + +`minadbd` is analogous to the regular `adbd`, but providing the minimal services to support +recovery-specific use cases. Generally speaking, `adbd` = `libadbd` + `libadbd_services`, whereas +`minadbd` = `libadbd` + `libminadbd_services`. + +Although both modules may be installed into the recovery image, only one of them, or none, can be +active at any given time. + +- The start / stop of `adbd` is managed via system property `sys.usb.config`, when setting to `adb` + or `none` respectively. Upon starting recovery mode, `adbd` is started in debuggable builds by + default; otherwise `adbd` will stay off at all times in user builds. See the triggers in + `bootable/recovery/etc/init.rc`. + +- `minadbd` is started by `recovery` as needed. + - When requested to start `minadbd`, `recovery` stops `adbd` first, if it's running; it then forks + and execs `minadbd` in a separate process. + - `minadbd` talks to host-side `adb` server to get user requests. + - `minadbd` handles some requests directly, e.g. querying device properties for rescue service. + - `minadbd` communicates with `recovery` to fulfill requests regarding package installation. See + the comments in `bootable/recovery/install/adb_install.cpp` for the IPC protocol between + `recovery` and `minadbd`. + - Upon exiting `minadbd`, `recovery` restarts `adbd` if it was previously running. -- cgit v1.2.3