libremanage

   1 #!/usr/bin/python3
   2
   3 """
   4 libremanage - Lightweight, free software for remote side-chanel server management
   5
   6 Copyright (C) 2018 Alyssa Rosenzweig
   7
   8 This program is free software: you can redistribute it and/or modify
   9 it under the terms of the GNU Affero General Public License as published by
  10 the Free Software Foundation, either version 3 of the License, or
  11 (at your option) any later version.
  12
  13 This program is distributed in the hope that it will be useful,
  14 but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 GNU Affero General Public License for more details.
  17
  18 You should have received a copy of the GNU Affero General Public License
  19 along with this program.  If not, see <https://www.gnu.org/licenses/>.
  20 """
  21
  22 USAGE = """
  23 Usage:
  24
  25     $ libremanage [server name] [command]
  26
  27 Example:
  28
  29     $ libremanage web2 reboot
  30
  31 Server names are defined in the accompanying config.py.
  32
  33 Valid commands are as follows:
  34
  35     - shutdown, reboot, poweron: Power management
  36     - tty: Open TTY in GNU Screen
  37     - sanity, sanity-sh: SSH sanity tests, ignore
  38
  39 Define a configuration file in ~/.libremanage.json. See the included
  40 config.json for an example. Servers correspond to managed servers; managers
  41 correspond to single-board computers connecting the servers. libremanage SSHs
  42 into the manager to access the server through the side-channel.
  43 """
  44
  45 import sys
  46 import json
  47 import functools
  48 import subprocess
  49 import time
  50 import os.path
  51
  52 def open_ssh(server, command, force_tty=False):
  53     config = server["ssh"]
  54     args = ["ssh"] + (["-t"] if force_tty else []) + [config["username"] + "@" + config["host"], "-p", str(config["port"]), command]
  55     subprocess.run(args)
  56
  57 def die_with_usage(message):
  58     print(message)
  59     print(USAGE)
  60     sys.exit(1)
  61
  62 def get_server_handle(name):
  63     if name == "localhost":
  64         return
  65
  66     try:
  67         server = CONFIG["servers"][name]
  68     except KeyError:
  69         die_with_usage("Unknown server, please configure")
  70
  71     # Associate manager configuration
  72     server["ssh"] = CONFIG["managers"][server["manager"]]
  73
  74     # Meta access
  75     server["name"] = name
  76
  77     return server
  78
  79 def gpio_export(server, pin, mode):
  80     if mode:
  81         open_ssh(server, "echo " + str(pin) + " > /sys/class/gpio/export")
  82         open_ssh(server, "echo out > /sys/class/gpio/gpio" + str(pin) + "/direction")
  83     else:
  84         open_ssh(server, "echo " + str(pin) + " > /sys/class/gpio/unexport")
  85
  86 def gpio_write(server, pin, value):
  87     open_ssh(server, "echo " + str(value) + " > /sys/class/gpio/gpio" + str(pin) + "/value")
  88
  89 def power_button(server, pin, state):
  90     # Hold down the power to force off (via the EC),
  91     # or just flick on to turn on
  92
  93     gpio_write(server, pin, 1)
  94     time.sleep(2 if state == POWER_OFF else 0.5)
  95     gpio_write(server, pin, 0)
  96
  97 POWER_OFF    = 0
  98 POWER_ON     = 1
  99 POWER_REBOOT = 2
 100
 101 def set_server_power(state, server):
 102     conf = server["power"]
 103
 104     # TODO: Invert
 105     # Export pin, configure, write value, unexport
 106     pin = conf["pin"]
 107
 108     gpio_export(server, pin, True)
 109
 110     # Act like a power button
 111
 112     if state == POWER_OFF or state == POWER_ON:
 113         power_button(server, pin, state)
 114     elif state == POWER_REBOOT:
 115         # Requires that we already be online.
 116         power_button(server, pin, POWER_OFF)
 117         power_button(server, pin, POWER_ON)
 118
 119     gpio_export(server, pin, False)
 120
 121 def open_tty(s):
 122     if s["tty"]["uncolor"]:
 123         # Broken serial port, workaround TTY garbage with libremanage-serial
 124         subprocess.run(["libremanage-serial", s["name"]])
 125     else:
 126         # Use native GNU screen
 127         return open_ssh(s, "screen " + s["tty"]["file"] + " " + str(s["tty"]["baud"]), force_tty=True),
 128
 129 COMMANDS = {
 130         # Power managemment
 131
 132         "shutdown": functools.partial(set_server_power, POWER_OFF),
 133         "poweron": functools.partial(set_server_power, POWER_ON),
 134         "reboot": functools.partial(set_server_power, POWER_REBOOT),
 135
 136         # TTY access (or keyboard if wired as such)
 137
 138         "tty": open_tty,
 139         "tty-baud": lambda s: open_ssh(s, "stty -F "+ s["tty"]["file"] + " " + str(s["tty"]["baud"])),
 140         "tty-read": lambda s: open_ssh(s, "cat " + s["tty"]["file"], force_tty=True),
 141         "tty-write": lambda s: open_ssh(s, "stdbuf -o0 cat > " + s["tty"]["file"], force_tty=True),
 142
 143         # SSH sanity tests
 144
 145         "sanity": lambda s: open_ssh(s, "whoami"),
 146         "sanity-sh": lambda s: open_ssh(s, ""),
 147 }
 148
 149 def issue_command(server_name, command):
 150     server = get_server_handle(server_name)
 151
 152     try:
 153         callback = COMMANDS[command]
 154     except KeyError:
 155         die_with_usage("Invalid command supplied")
 156
 157     callback(server)
 158
 159 # Load configuration, get command, and go!
 160
 161 try:
 162     with open(os.path.expanduser("~/.libremanage.json")) as f:
 163         CONFIG = json.load(f)
 164 except FileNotFoundError:
 165     die_with_usage("Configuration file missing in ~/.libremanage.json")
 166
 167 if len(sys.argv) != 3:
 168     die_with_usage("Incorrect number of arguments")
 169
 170 issue_command(sys.argv[1], sys.argv[2])