remoting/host/installer/mac/PrivilegedHelperTools/org.chromium.chromoting.me2me.sh

   1 #!/bin/sh
   2
   3 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
   4 # Use of this source code is governed by a BSD-style license that can be
   5 # found in the LICENSE file.
   6
   7 NAME=org.chromium.chromoting
   8 HOST_BUNDLE_NAME=@@HOST_BUNDLE_NAME@@
   9 PREFPANE_BUNDLE_NAME=@@PREFPANE_BUNDLE_NAME@@
  10 CONFIG_DIR=/Library/PrivilegedHelperTools
  11 ENABLED_FILE=$CONFIG_DIR/$NAME.me2me_enabled
  12 CONFIG_FILE=$CONFIG_DIR/$NAME.json
  13 HOST_EXE=$CONFIG_DIR/$HOST_BUNDLE_NAME/Contents/MacOS/remoting_me2me_host
  14 PLIST_FILE=$CONFIG_DIR/$HOST_BUNDLE_NAME/Contents/Info.plist
  15 PREF_PANE_BUNDLE=/Library/PreferencePanes/$PREFPANE_BUNDLE_NAME
  16
  17 # The exit code returned by 'wait' when a process is terminated by SIGTERM.
  18 SIGTERM_EXIT_CODE=143
  19
  20 # Range of exit codes returned by the host to indicate that a permanent error
  21 # has occurred and that the host should not be restarted. Please, keep these
  22 # constants in sync with remoting/host/host_exit_codes.h.
  23 MIN_PERMANENT_ERROR_EXIT_CODE=100
  24 MAX_PERMANENT_ERROR_EXIT_CODE=105
  25
  26 # Constants controlling the host process relaunch throttling.
  27 MINIMUM_RELAUNCH_INTERVAL=60
  28 MAXIMUM_HOST_FAILURES=10
  29
  30 # Exit code 126 is defined by Posix to mean "Command found, but not
  31 # executable", and is returned if the process cannot be launched due to
  32 # parental control.
  33 PERMISSION_DENIED_PARENTAL_CONTROL=126
  34
  35 HOST_PID=0
  36 SIGNAL_WAS_TRAPPED=0
  37
  38 # This script works as a proxy between launchd and the host. Signals of
  39 # interest to the host must be forwarded.
  40 SIGNAL_LIST="SIGHUP SIGINT SIGQUIT SIGILL SIGTRAP SIGABRT SIGEMT \
  41       SIGFPE SIGKILL SIGBUS SIGSEGV SIGSYS SIGPIPE SIGALRM SIGTERM SIGURG \
  42       SIGSTOP SIGTSTP SIGCONT SIGCHLD SIGTTIN SIGTTOU SIGIO SIGXCPU SIGXFSZ \
  43       SIGVTALRM SIGPROF SIGWINCH SIGINFO SIGUSR1 SIGUSR2"
  44
  45 handle_signal() {
  46   SIGNAL_WAS_TRAPPED=1
  47 }
  48
  49 run_host() {
  50   local host_failure_count=0
  51   local host_start_time=0
  52
  53   while true; do
  54     if [[ ! -f "$ENABLED_FILE" ]]; then
  55       echo "Daemon is disabled."
  56       exit 0
  57     fi
  58
  59     # If this is not the first time the host has run, make sure we don't
  60     # relaunch it too soon.
  61     if [[ "$host_start_time" -gt 0 ]]; then
  62       local host_lifetime=$(($(date +%s) - $host_start_time))
  63       echo "Host ran for ${host_lifetime}s"
  64       if [[ "$host_lifetime" -lt "$MINIMUM_RELAUNCH_INTERVAL" ]]; then
  65         # If the host didn't run for very long, assume it crashed. Relaunch only
  66         # after a suitable delay and increase the failure count.
  67         host_failure_count=$(($host_failure_count + 1))
  68         echo "Host failure count $host_failure_count/$MAXIMUM_HOST_FAILURES"
  69         if [[ "$host_failure_count" -ge "$MAXIMUM_HOST_FAILURES" ]]; then
  70           echo "Too many host failures. Giving up."
  71           exit 1
  72         fi
  73         local relaunch_in=$(($MINIMUM_RELAUNCH_INTERVAL - $host_lifetime))
  74         echo "Relaunching in ${relaunch_in}s"
  75         sleep "$relaunch_in"
  76       else
  77         # If the host ran for long enough, reset the crash counter.
  78         host_failure_count=0
  79       fi
  80     fi
  81
  82     # Execute the host asynchronously and forward signals to it.
  83     trap "handle_signal" $SIGNAL_LIST
  84     host_start_time=$(date +%s)
  85     "$HOST_EXE" --host-config="$CONFIG_FILE" &
  86     HOST_PID="$!"
  87
  88     # Wait for the host to return and process its exit code.
  89     while true; do
  90       wait "$HOST_PID"
  91       EXIT_CODE="$?"
  92       if [[ $SIGNAL_WAS_TRAPPED -eq 1 ]]; then
  93         # 'wait' returned as the result of a trapped signal and the exit code is
  94         # the signal that was trapped + 128. Forward the signal to the host.
  95         SIGNAL_WAS_TRAPPED=0
  96         local SIGNAL=$(($EXIT_CODE - 128))
  97         echo "Forwarding signal $SIGNAL to host"
  98         kill -$SIGNAL "$HOST_PID"
  99       elif [[ "$EXIT_CODE" -eq "0" ||
 100               "$EXIT_CODE" -eq "$SIGTERM_EXIT_CODE" ||
 101               "$EXIT_CODE" -eq "$PERMISSION_DENIED_PARENTAL_CONTROL" ||
 102               ("$EXIT_CODE" -ge "$MIN_PERMANENT_ERROR_EXIT_CODE" && \
 103               "$EXIT_CODE" -le "$MAX_PERMANENT_ERROR_EXIT_CODE") ]]; then
 104         echo "Host returned permanent exit code $EXIT_CODE at ""$(date)"""
 105         if [[ "$EXIT_CODE" -eq 101 ]]; then
 106           # Exit code 101 is "hostID deleted", which indicates that the host
 107           # was taken off-line remotely. To prevent the host being restarted
 108           # when the login context changes, try to delete the "enabled" file.
 109           # Since this requires root privileges, this is only possible when
 110           # this script is launched in the "login" context. In the "aqua"
 111           # context, just exit and try again next time.
 112           echo "Host id deleted - disabling"
 113           rm -f "$ENABLED_FILE" 2>/dev/null
 114         fi
 115         exit "$EXIT_CODE"
 116       else
 117         # Ignore non-permanent error-code and launch host again. Stop handling
 118         # signals temporarily in case the script has to sleep to throttle host
 119         # relaunches. While throttling, there is no host process to which to
 120         # forward the signal, so the default behaviour should be restored.
 121         echo "Host returned non-permanent exit code $EXIT_CODE at ""$(date)"""
 122         trap - $SIGNAL_LIST
 123         HOST_PID=0
 124         break
 125       fi
 126     done
 127   done
 128 }
 129
 130 if [[ "$1" = "--disable" ]]; then
 131   # This script is executed from base::mac::ExecuteWithPrivilegesAndWait(),
 132   # which requires the child process to write its PID to stdout before
 133   # anythine else. See base/mac/authorization_util.h for details.
 134   echo $$
 135   rm -f "$ENABLED_FILE"
 136 elif [[ "$1" = "--enable" ]]; then
 137   echo $$
 138   # Ensure the config file is private whilst being written.
 139   rm -f "$CONFIG_FILE"
 140   umask 0077
 141   cat > "$CONFIG_FILE"
 142   # Ensure the config is readable by the user registering the host.
 143   chmod +a "$USER:allow:read" "$CONFIG_FILE"
 144   touch "$ENABLED_FILE"
 145 elif [[ "$1" = "--save-config" ]]; then
 146   echo $$
 147   cat > "$CONFIG_FILE"
 148 elif [[ "$1" = "--host-version" ]]; then
 149   /usr/libexec/PlistBuddy -c "Print CFBundleVersion" "$PLIST_FILE"
 150 elif [[ "$1" = "--relaunch-prefpane" ]]; then
 151   # Wait for the parent (System Preferences applet) to die, by reading from
 152   # stdin until the pipe is broken.
 153   cat 2>/dev/null || true
 154   open "$PREF_PANE_BUNDLE"
 155 elif [[ "$1" = "--run-from-launchd" ]]; then
 156   echo Host started for user $USER at $"$(date)"
 157   run_host
 158 else
 159   echo $$
 160   exit 1
 161 fi