filesync_protocol.txt

The missing sync.txt from android's ADB.

Message Format:
  Every message starts with a single 32-bit word. (Everything is little-endian).
  Depending on that first word, the rest of the data can have various meanings.
  Messages from the host/desktop to the device always start with a 'request'
    message of a u32 command, u32 size, and size more bytes that's a filename,
    directory or symlink.
  The command here is referred to as 'id' in the code and the 4-letter codes
    are prefixed by ID_, eg ID_STAT.

  STAT:
    request:
      u32 command = 'STAT' == 0x53544154
      u32 size = len(filename) < 1024
      u8 data[size] = filename (no null)

    response:
      struct stat st = lstat(filename)
      u32 command = 'STAT'
      u32 mode = st.st_mode
      u32 size = st.st_size
      u32 time = st.st_mtime

  LIST:
    request:
      u32 command = 'LIST' == 0x4C495354
      u32 size = len(path) < 1024
      u8 data[size] = path (no null)

    response:
    for each filename in listing of path:
      struct stat st = lstat(filename)
      u32 command = 'DENT' == 0x44454E54
      u32 mode = st.st_mode
      u32 size = st.st_size
      u32 time = st.st_mtime
      u32 namelen = len(filename)
      u8 data[namelen] = filename

    done (device -> host):
      u32 command = 'DONE' == 0x444F4E45
      u32[4] = 0

  SEND:
    struct stat st = lstat(filename)
    request:
      fileinfo = sprintf(',%d', st.st_mode)
      u32 command = 'SEND' == 0x53454E44
      u32 size = len(filename) + len(fileinfo) < 1024
      u8 data[size] = filename + fileinfo

    repeated data command (host -> device):
      u32 command = 'DATA' == 0x44415441
      u32 size < (64 * 1024)
      u8 data[size] = file contents

    finish command (host -> device):
      u32 command = 'DONE' == 0x444F4E45
      u32 timestamp = st.st_mtime

    response (device -> host):
      u32 command = 'OKAY' == 0x4F4B4159 or 'FAIL' == 0x4641494C
      u32 size = 0 if 'OKAY' else len(fail_message)
      u8 data[] = fail_message

  RECV:
    request:
      u32 command = 'RECV' == 0x52454356
      u32 size = len(filename)
      u8 data[size] = filename

    repeated data response (device -> host):
      u32 command = 'DATA' == 0x44415441
      u32 size < (64 * 1024)
      u8 data[size] = file contents

    finish response (device -> host):
      u32 command = 'DONE' == 0x444F4E45
      u32 size = 0