bin/crosh - chromiumos/platform/window_manager - Git at Google

 #!/bin/dash
 # Copyright (c) 2009-2010 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.

 TRY_BASH=1
 if echo "$@" | grep -q -- "--dash"; then
   TRY_BASH=0
 fi

 # NOTE: This script *almost* works in dash.  Unfortunately, dash is missing
 # the 'history' builtin and readline support is missing from the 'read'
 # builtin.
 #
 # Please test that any changes continue to work in dash by running
 # '/build/board-name/bin/dash crosh --dash' before checking them in.

 if type "history" 2>/dev/null | grep -q "shell builtin"; then
   IS_BASH=1
 else
   IS_BASH=0
 fi

 if [ "$TRY_BASH" = "1" -a "$IS_BASH" != "1" -a -x "/bin/bash" ]; then
   # Relaunch in bash if we can.
   exec /bin/bash $0 "$@"
 fi

 #
 # Please keep the help text in alphabetical order!
 #
 HELP='
  enterprise_ca_approve [--allow-self-signed] <url>
   Approve an enterprise certificate authority.  The <url> option should be
   an http or https url to your enterprise Certificate Authority in PEM
   format.  This CA will be used to validate the signature of an enterprise
   policy extension.

   If the --allow-self-signed option is provided, then you may provide a self
   signed CA.  Use this only if you are certain of the source of the CA.

  enterprise_ca_disapprove
   Remove a previously approved enterprise certificate authority.

  exit
   Exit crosh.

  ff_debug [<tag_expr>] [--help] [--list_valid_tags] [--reset]
   Add and remove flimflam debugging tags.

  help
   Display this help.

  modem <command> [args...]
   Interact with the 3G modem. Run "modem help" for detailed help.

  modem_set_carrier carrier-name
   Configures the modem for the specified carrier.

  network_logging <wifi | cellular | ethernet>
   A function that enables a predefined set of tags useful for
   debugging the specified device.

  network_diag
   A function that performs a suite of network diagnostics.  Saves a copy
   of the output to your download directory.

  ping [-c count] [-i interval] [-n] [-s packet-size] [-W wait-time] <destination>
   Send ICMP ECHO_REQUEST packets to a network host.  If <destination> is "gw"
   then the next hop gateway for the default route is used.

  route [-n]
   Display the routing tables.

  set_apn [-n <network-id>] [-u <username>] [-p <password>] <apn>
   Set the APN to use when connecting to the network specified by <network-id>.
   If <network-id> is not specified, use the network-id of the currently
   registered network.

  set_apn -c
   Clear the APN to be used, so that the default APN will be used instead.

  ssh <user> <host> [<port>]
   Open an ssh connection to the given <host>, as <user>.  The <port> parameter
   is optional and defaults to 22.

  ssh_forget_host
   Remove a host from the list of known ssh hosts.  This command displays
   a menu of known hosts and prompts for the host to forget.

  top
   Run top.

  tracepath [-n] <destination>[/port]
   Trace the path/route to a network host.

  wpa_debug [<debug_level>] [--help] [--list_valid_level] [--reset]
   Set wpa_supplicant debugging level.
 '

 CHROMEOS_INSTALL=/usr/sbin/chromeos-install

 if [ -f $CHROMEOS_INSTALL ]; then
   # Install script exists.  Test if it thinks we booted from a removable
   # device.  This is based on the knowledge that the install script checks
   # that the root device is removable before validating its other arguments.
   # Also, we expect that when it fails in this manner, it mentions the word
   # "removable" on stdout.

   if ! $CHROMEOS_INSTALL --dst=/dev/null | grep -q "removable"; then
     REMOVABLE=1
   fi
 fi

 if [ "$(echo "$@" | grep -- "--usb")" -o "$REMOVABLE" = "1" ]; then
   . "$(dirname "$0")/crosh-usb"
 fi

 # TODO(rginda): Switch to the "real" dev mode file when we have one.
 /usr/bin/crossystem cros_debug?1
 DEVMODE=$((!$?))
 # Force dev behavior on dev images
 # TODO(wad,rspangler) replace with a crossystem arg once cros_debug checks this
 # too.
 if [ -f "/root/.dev_mode" ]; then
   DEVMODE=1
 fi

 if [ "$(echo "$@" | grep -- "--dev")" -o "$DEVMODE" = "1" ]; then
   . "$(dirname "$0")/crosh-dev"
 fi

 if [ -e "$(dirname $0)/crosh-workarounds" ]; then
   . "$(dirname "$0")/crosh-workarounds"
 fi

 shell_read() {
   local prompt="$1"
   shift

   if [ "$IS_BASH" -eq "1" ]; then
     # In bash, -e gives readline support.
     read -p "$prompt" -e $@
   else
     read -p "$prompt" $@
   fi
 }

 shell_history() {
   if [ "$IS_BASH" -eq "1" ]; then
     # In bash, the history builtin can be used to manage readline history
     history $@
   fi
 }

 cmd_help() {
   echo "$HELP"
 }

 cmd_exit() {
   exit
 }

 cmd_ssh() {
   local user="$1"
   local host="$2"
   local port="${3:-22}"

   # Ssh consults /etc/passwd for the home directory, rather than trusting
   # $HOME.  This is a problem for us because $HOME is /home/chronos/user, while
   # /etc/passwd lists /home/chronos.  We work around it by reading /etc/passwd
   # too.
   local home="$(getent passwd "$USER" | cut -f6 -d':')"
   rm -rf $home/.ssh

   if [ -z "$user" ]; then
     echo "Missing required parameter: user"
     return
   elif ! check_username "$user"; then
     echo "Invalid user: $user"
     return
   fi

   if [ -z "$host" ]; then
     echo "Missing required parameter: host"
     return
   elif ! check_hostname "$host" && ! check_ipv6 "$host"; then
     echo "Invalid host: $host"
     return
   fi

   if [ ! -z "$port" ]; then
     if ! check_digits "$port"; then
       echo "Invalid port: $port"
       return
     fi
   fi

   echo "open: host: $host, user: $user, port: $port"
   ssh -e none -F /etc/ssh/ssh_config -p "$port" "$user@$host"
 }

 cmd_ssh_forget_host() {
   local known_hosts="$(readlink -f $HOME/.ssh/known_hosts)"

   # Test that the known_hosts is a regular file and is not 0 length.
   if [ ! -f "$known_hosts" -o ! -s "$known_hosts" ]; then
     echo "No known hosts."
     return
   fi

   local count="$(cat "$known_hosts" | wc -l)"

   # Print an indexed list of the known hosts.
   echo "Known hosts:"
   awk '{ print " " NR ") " $1; }' "$known_hosts"

   local hostno

   while true; do
     LINE_=""
     shell_read "Please select a host to forget [1-$count]: " LINE_
     if [ -z "$LINE_" ]; then
       echo "Aborting."
       return
     fi

     # Extract the numbers from the user input.
     hostno="$(echo $LINE_ | sed 's/[^[:digit:]]*//g')"

     # If they typed a number...
     if [ -n "$hostno" ]; then
       # And it was in the proper range...
       if [ $hostno -gt 0 -a $hostno -le $count ]; then
         # Then we can stop asking for input.
         break
       fi
     fi

     echo "Invalid selection.  Please enter a number between 1 and $count."
   done

   local trimmed="$(awk -v I="$hostno" 'NR != I { print }' "$known_hosts")"
   echo "$trimmed" > "$known_hosts"
   chmod 644 "$known_hosts"
 }

 cmd_enterprise_ca_approve() {
   local option=""

   while [ "$(echo "$1" | cut -c1-2)" = "--" ]; do
     if [ "$1" = "--allow-self-signed" ]; then
       option="$option --allow_self_signed"
     elif [ "$1" = "--allow-chaining" ]; then
       # This option allows enterprise extensions which are signed by
       # certificates that chain to this one.  Because we're not currently
       # doing any key usage checks, this can be pretty risky.  If you're not
       # sure that you need this, don't use it.
       option="$option --allow_chaining"
     else
       echo "Unknown option: $1"
       return 1
     fi

     shift
   done

   if [ -z "$1" ]; then
     echo "Missing parameter: url"
     return 1
   fi

   /usr/sbin/entdwife.sh -c approve $option -C "$1"
 }

 cmd_enterprise_ca_disapprove() {
   /usr/sbin/entdwife.sh -c disapprove
 }

 cmd_ff_debug(){
   /usr/bin/ff_debug "$@"
 }

 cmd_wpa_debug(){
   /usr/bin/wpa_debug "$@"
 }

 cmd_network_logging(){
   if [ -n "$1" ]; then
     case "$1" in
       "wifi")
         echo; /usr/bin/ff_debug service+wifi+inet+device+manager
         echo; /usr/bin/wpa_debug msgdump
         ;;
       "cellular")
         echo; /usr/bin/ff_debug service+modem+device+manager
         echo; /usr/bin/wpa_debug info
         ;;
       "ethernet")
         echo; /usr/bin/ff_debug service+ethernet+device+manager
         echo; /usr/bin/wpa_debug info
         ;;
       "--help")
         echo "Usage: network_logging <wifi | cellular | ethernet>"
         ;;
       *)
         echo "Invalid parameter $1"
         ;;
     esac
   else
     echo "Missing parameter wifi | cellular | ethernet"
   fi
 }

 cmd_network_diag(){
   /usr/bin/network_diagnostics
 }

 cmd_ping() {
   local option=""

   # NB: use printf to avoid echo interpreting -n
   while [ "$(printf '%s' "$1" | cut -c1)" = "-" ]; do
     # Do just enough parsing to filter/map options; we
     # depend on ping to handle final validation
     if [ "$1" = "-i" ]; then
       shift; option="$option -i $1"
     elif [ "$1" = "-c" ]; then
       shift; option="$option -c $1"
     elif [ "$1" = "-W" ]; then
       shift; option="$option -W $1"
     elif [ "$1" = "-s" ]; then
       shift; option="$option -s $1"
     elif [ "$1" = "-n" ]; then
       option="$option -n"
     else
       echo "Unknown option: $1"
       return 1
     fi

     shift
   done

   if [ -z "$1" ]; then
     echo "Missing parameter: destination"
     return 1
   fi

   local dest="$1"
   if [ "$dest" = "gw" ]; then
     # Convenient shorthand for the next-hop gateway attached
     # to the default route; this means if you have a host named
     # "gw" then you'll need to specify a FQDN or IP address.
     dest=$(/sbin/route -n | awk '$1 == "0.0.0.0" { print $2; }')
     if [ -z "$dest" ]; then
       echo "Cannot determine primary gateway; routing table is:"
       cmd_route -n
       return 1
     fi
   fi

   /bin/ping $option "$dest"
 }

 cmd_route() {
   local option=""

   # NB: use printf to avoid echo interpreting -n
   while [ "$(printf '%s' "$1" | cut -c1)" = "-" ]; do
     if [ "$1" = "-n" ]; then
       option="$option -n"
     else
       echo "Unknown option: $1"
       return 1
     fi

     shift
   done

   /sbin/route $option
 }

 cmd_tracepath() {
   local option=""

   # NB: use printf to avoid echo interpreting -n
   while [ "$(printf '%s' "$1" | cut -c1)" = "-" ]; do
     if [ "$1" = "-n" ]; then
       option="$option -n"
     else
       echo "Unknown option: $1"
       return 1
     fi

     shift
   done

   if [ -z "$1" ]; then
     echo "Missing parameter: destination"
     return 1
   fi

   /usr/sbin/tracepath $option "$1"
 }

 cmd_top() {
   # -s is "secure" mode, which disables kill, renice, and change display/sleep
   # interval.
   top -s
 }

 cmd_modem() {
   /usr/bin/modem "$@"
 }

 cmd_modem_set_carrier() {
   /usr/bin/modem_set_carrier "$@"
 }

 cmd_set_apn() {
   /usr/bin/set_apn "$@"
 }

 substr() {
   local str="$1"
   local start="$2"
   local end="$3"

   if [ "$IS_BASH" = "1" ]; then
     # NB: use printf to avoid echo interpreting -n
     if [ -z "$end" ]; then
       printf '%s\n' ${str:$start}
     else
       printf '%s\n' ${str:$start:$end}
     fi
     return
   fi

   start=$(expr "$start" + 1)

   if [ ! -z "$end" ]; then
     end=$(expr "$end" - 1)
   fi

   echo "$str" | cut -c${start}-${end}
 }

 dispatch() {
   local line="$1"
   local command=""
   local params=""

   local space_pos=$(expr index "$line" ' ')

   if [ $space_pos = 0 ]; then
     command=$line
   else
     command=$(substr "$line" "0" "$space_pos")
     params=$(substr "$line" "$space_pos")
   fi

   if ! type "cmd_$command" 2>/dev/null | head -1 | grep -q "function"; then
     echo "Unknown command: '$command'"
   else
     command="cmd_$command"
     $command $params
   fi
 }

 # Checks that a given string looks like a hostname or IPv4 address (starts
 # with an alphanumeric and contains only alphanumeric, '.', or '-'
 # characters).
 check_hostname() {
   expr "$1" : '^[[:alnum:]][-[:alnum:].]*$' > /dev/null
 }

 # Checks that a given string could plausibly be an IPv6 address
 # (hexadecimal, ':', and '.' characters only, followed by an optional zone
 # index consisting of a '%' and a device name).
 check_ipv6() {
   echo "$1" | /bin/grep -E -q '^[0-9a-fA-F:.]+(%[a-z0-9]+)?$'
 }

 # Checks that a given string starts with an alphanumeric, and contains only
 # alphanumeric and zero or more of ":.~%$^\-"
 check_username() {
   expr "$1" : '^[[:alnum:]][[:alnum:]:.~%$^\-]*$' > /dev/null
 }

 check_digits() {
   expr "$1" : '^[[:digit:]]*$' > /dev/null
 }

 repl() {
   echo "Welcome to crosh, type 'help' for a list of commands."
   if [ "$IS_BASH" != "1" ]; then
     echo "Sorry, line editing and command history disabled due to" \
       "shell limitations."
   fi

   while [ 1 ]; do
     if shell_read "crosh> " LINE_; then
       if [ ! -z "$LINE_" ]; then
         shell_history -s "$LINE_"
         dispatch "$LINE_"
       fi
     else
       echo
       return 1
     fi
   done
 }

 INPUTRC="$(dirname "$0")/inputrc.crosh"
 HISTFILE="$HOME/.crosh_history"
 shell_history -r $HISTFILE

 repl

 shell_history -w $HISTFILE
	#!/bin/dash
	# Copyright (c) 2009-2010 The Chromium OS Authors. All rights reserved.
	# Use of this source code is governed by a BSD-style license that can be
	# found in the LICENSE file.

	TRY_BASH=1
	if echo "$@" \| grep -q -- "--dash"; then
	TRY_BASH=0
	fi

	# NOTE: This script almost works in dash. Unfortunately, dash is missing
	# the 'history' builtin and readline support is missing from the 'read'
	# builtin.
	#
	# Please test that any changes continue to work in dash by running
	# '/build/board-name/bin/dash crosh --dash' before checking them in.

	if type "history" 2>/dev/null \| grep -q "shell builtin"; then
	IS_BASH=1
	else
	IS_BASH=0
	fi

	if [ "$TRY_BASH" = "1" -a "$IS_BASH" != "1" -a -x "/bin/bash" ]; then
	# Relaunch in bash if we can.
	exec /bin/bash $0 "$@"
	fi

	#
	# Please keep the help text in alphabetical order!
	#
	HELP='
	enterprise_ca_approve [--allow-self-signed] <url>
	Approve an enterprise certificate authority. The <url> option should be
	an http or https url to your enterprise Certificate Authority in PEM
	format. This CA will be used to validate the signature of an enterprise
	policy extension.

	If the --allow-self-signed option is provided, then you may provide a self
	signed CA. Use this only if you are certain of the source of the CA.

	enterprise_ca_disapprove
	Remove a previously approved enterprise certificate authority.

	exit
	Exit crosh.

	ff_debug [<tag_expr>] [--help] [--list_valid_tags] [--reset]
	Add and remove flimflam debugging tags.

	help
	Display this help.

	modem <command> [args...]
	Interact with the 3G modem. Run "modem help" for detailed help.

	modem_set_carrier carrier-name
	Configures the modem for the specified carrier.

	network_logging <wifi \| cellular \| ethernet>
	A function that enables a predefined set of tags useful for
	debugging the specified device.

	network_diag
	A function that performs a suite of network diagnostics. Saves a copy
	of the output to your download directory.

	ping [-c count] [-i interval] [-n] [-s packet-size] [-W wait-time] <destination>
	Send ICMP ECHO_REQUEST packets to a network host. If <destination> is "gw"
	then the next hop gateway for the default route is used.

	route [-n]
	Display the routing tables.

	set_apn [-n <network-id>] [-u <username>] [-p <password>] <apn>
	Set the APN to use when connecting to the network specified by <network-id>.
	If <network-id> is not specified, use the network-id of the currently
	registered network.

	set_apn -c
	Clear the APN to be used, so that the default APN will be used instead.

	ssh <user> <host> [<port>]
	Open an ssh connection to the given <host>, as <user>. The <port> parameter
	is optional and defaults to 22.

	ssh_forget_host
	Remove a host from the list of known ssh hosts. This command displays
	a menu of known hosts and prompts for the host to forget.

	top
	Run top.

	tracepath [-n] <destination>[/port]
	Trace the path/route to a network host.

	wpa_debug [<debug_level>] [--help] [--list_valid_level] [--reset]
	Set wpa_supplicant debugging level.
	'

	CHROMEOS_INSTALL=/usr/sbin/chromeos-install

	if [ -f $CHROMEOS_INSTALL ]; then
	# Install script exists. Test if it thinks we booted from a removable
	# device. This is based on the knowledge that the install script checks
	# that the root device is removable before validating its other arguments.
	# Also, we expect that when it fails in this manner, it mentions the word
	# "removable" on stdout.

	if ! $CHROMEOS_INSTALL --dst=/dev/null \| grep -q "removable"; then
	REMOVABLE=1
	fi
	fi

	if [ "$(echo "$@" \| grep -- "--usb")" -o "$REMOVABLE" = "1" ]; then
	. "$(dirname "$0")/crosh-usb"
	fi

	# TODO(rginda): Switch to the "real" dev mode file when we have one.
	/usr/bin/crossystem cros_debug?1
	DEVMODE=$((!$?))
	# Force dev behavior on dev images
	# TODO(wad,rspangler) replace with a crossystem arg once cros_debug checks this
	# too.
	if [ -f "/root/.dev_mode" ]; then
	DEVMODE=1
	fi

	if [ "$(echo "$@" \| grep -- "--dev")" -o "$DEVMODE" = "1" ]; then
	. "$(dirname "$0")/crosh-dev"
	fi

	if [ -e "$(dirname $0)/crosh-workarounds" ]; then
	. "$(dirname "$0")/crosh-workarounds"
	fi

	shell_read() {
	local prompt="$1"
	shift

	if [ "$IS_BASH" -eq "1" ]; then
	# In bash, -e gives readline support.
	read -p "$prompt" -e $@
	else
	read -p "$prompt" $@
	fi
	}

	shell_history() {
	if [ "$IS_BASH" -eq "1" ]; then
	# In bash, the history builtin can be used to manage readline history
	history $@
	fi
	}

	cmd_help() {
	echo "$HELP"
	}

	cmd_exit() {
	exit
	}

	cmd_ssh() {
	local user="$1"
	local host="$2"
	local port="${3:-22}"

	# Ssh consults /etc/passwd for the home directory, rather than trusting
	# $HOME. This is a problem for us because $HOME is /home/chronos/user, while
	# /etc/passwd lists /home/chronos. We work around it by reading /etc/passwd
	# too.
	local home="$(getent passwd "$USER" \| cut -f6 -d':')"
	rm -rf $home/.ssh

	if [ -z "$user" ]; then
	echo "Missing required parameter: user"
	return
	elif ! check_username "$user"; then
	echo "Invalid user: $user"
	return
	fi

	if [ -z "$host" ]; then
	echo "Missing required parameter: host"
	return
	elif ! check_hostname "$host" && ! check_ipv6 "$host"; then
	echo "Invalid host: $host"
	return
	fi

	if [ ! -z "$port" ]; then
	if ! check_digits "$port"; then
	echo "Invalid port: $port"
	return
	fi
	fi

	echo "open: host: $host, user: $user, port: $port"
	ssh -e none -F /etc/ssh/ssh_config -p "$port" "$user@$host"
	}

	cmd_ssh_forget_host() {
	local known_hosts="$(readlink -f $HOME/.ssh/known_hosts)"

	# Test that the known_hosts is a regular file and is not 0 length.
	if [ ! -f "$known_hosts" -o ! -s "$known_hosts" ]; then
	echo "No known hosts."
	return
	fi

	local count="$(cat "$known_hosts" \| wc -l)"

	# Print an indexed list of the known hosts.
	echo "Known hosts:"
	awk '{ print " " NR ") " $1; }' "$known_hosts"

	local hostno

	while true; do
	LINE_=""
	shell_read "Please select a host to forget [1-$count]: " LINE_
	if [ -z "$LINE_" ]; then
	echo "Aborting."
	return
	fi

	# Extract the numbers from the user input.
	hostno="$(echo $LINE_ \| sed 's/[^[:digit:]]*//g')"

	# If they typed a number...
	if [ -n "$hostno" ]; then
	# And it was in the proper range...
	if [ $hostno -gt 0 -a $hostno -le $count ]; then
	# Then we can stop asking for input.
	break
	fi
	fi

	echo "Invalid selection. Please enter a number between 1 and $count."
	done

	local trimmed="$(awk -v I="$hostno" 'NR != I { print }' "$known_hosts")"
	echo "$trimmed" > "$known_hosts"
	chmod 644 "$known_hosts"
	}

	cmd_enterprise_ca_approve() {
	local option=""

	while [ "$(echo "$1" \| cut -c1-2)" = "--" ]; do
	if [ "$1" = "--allow-self-signed" ]; then
	option="$option --allow_self_signed"
	elif [ "$1" = "--allow-chaining" ]; then
	# This option allows enterprise extensions which are signed by
	# certificates that chain to this one. Because we're not currently
	# doing any key usage checks, this can be pretty risky. If you're not
	# sure that you need this, don't use it.
	option="$option --allow_chaining"
	else
	echo "Unknown option: $1"
	return 1
	fi

	shift
	done

	if [ -z "$1" ]; then
	echo "Missing parameter: url"
	return 1
	fi

	/usr/sbin/entdwife.sh -c approve $option -C "$1"
	}

	cmd_enterprise_ca_disapprove() {
	/usr/sbin/entdwife.sh -c disapprove
	}

	cmd_ff_debug(){
	/usr/bin/ff_debug "$@"
	}

	cmd_wpa_debug(){
	/usr/bin/wpa_debug "$@"
	}

	cmd_network_logging(){
	if [ -n "$1" ]; then
	case "$1" in
	"wifi")
	echo; /usr/bin/ff_debug service+wifi+inet+device+manager
	echo; /usr/bin/wpa_debug msgdump
	;;
	"cellular")
	echo; /usr/bin/ff_debug service+modem+device+manager
	echo; /usr/bin/wpa_debug info
	;;
	"ethernet")
	echo; /usr/bin/ff_debug service+ethernet+device+manager
	echo; /usr/bin/wpa_debug info
	;;
	"--help")
	echo "Usage: network_logging <wifi \| cellular \| ethernet>"
	;;
	*)
	echo "Invalid parameter $1"
	;;
	esac
	else
	echo "Missing parameter wifi \| cellular \| ethernet"
	fi
	}

	cmd_network_diag(){
	/usr/bin/network_diagnostics
	}

	cmd_ping() {
	local option=""

	# NB: use printf to avoid echo interpreting -n
	while [ "$(printf '%s' "$1" \| cut -c1)" = "-" ]; do
	# Do just enough parsing to filter/map options; we
	# depend on ping to handle final validation
	if [ "$1" = "-i" ]; then
	shift; option="$option -i $1"
	elif [ "$1" = "-c" ]; then
	shift; option="$option -c $1"
	elif [ "$1" = "-W" ]; then
	shift; option="$option -W $1"
	elif [ "$1" = "-s" ]; then
	shift; option="$option -s $1"
	elif [ "$1" = "-n" ]; then
	option="$option -n"
	else
	echo "Unknown option: $1"
	return 1
	fi

	shift
	done

	if [ -z "$1" ]; then
	echo "Missing parameter: destination"
	return 1
	fi

	local dest="$1"
	if [ "$dest" = "gw" ]; then
	# Convenient shorthand for the next-hop gateway attached
	# to the default route; this means if you have a host named
	# "gw" then you'll need to specify a FQDN or IP address.
	dest=$(/sbin/route -n \| awk '$1 == "0.0.0.0" { print $2; }')
	if [ -z "$dest" ]; then
	echo "Cannot determine primary gateway; routing table is:"
	cmd_route -n
	return 1
	fi
	fi

	/bin/ping $option "$dest"
	}

	cmd_route() {
	local option=""

	# NB: use printf to avoid echo interpreting -n
	while [ "$(printf '%s' "$1" \| cut -c1)" = "-" ]; do
	if [ "$1" = "-n" ]; then
	option="$option -n"
	else
	echo "Unknown option: $1"
	return 1
	fi

	shift
	done

	/sbin/route $option
	}

	cmd_tracepath() {
	local option=""

	# NB: use printf to avoid echo interpreting -n
	while [ "$(printf '%s' "$1" \| cut -c1)" = "-" ]; do
	if [ "$1" = "-n" ]; then
	option="$option -n"
	else
	echo "Unknown option: $1"
	return 1
	fi

	shift
	done

	if [ -z "$1" ]; then
	echo "Missing parameter: destination"
	return 1
	fi

	/usr/sbin/tracepath $option "$1"
	}

	cmd_top() {
	# -s is "secure" mode, which disables kill, renice, and change display/sleep
	# interval.
	top -s
	}

	cmd_modem() {
	/usr/bin/modem "$@"
	}

	cmd_modem_set_carrier() {
	/usr/bin/modem_set_carrier "$@"
	}

	cmd_set_apn() {
	/usr/bin/set_apn "$@"
	}

	substr() {
	local str="$1"
	local start="$2"
	local end="$3"

	if [ "$IS_BASH" = "1" ]; then
	# NB: use printf to avoid echo interpreting -n
	if [ -z "$end" ]; then
	printf '%s\n' ${str:$start}
	else
	printf '%s\n' ${str:$start:$end}
	fi
	return
	fi

	start=$(expr "$start" + 1)

	if [ ! -z "$end" ]; then
	end=$(expr "$end" - 1)
	fi

	echo "$str" \| cut -c${start}-${end}
	}

	dispatch() {
	local line="$1"
	local command=""
	local params=""

	local space_pos=$(expr index "$line" ' ')

	if [ $space_pos = 0 ]; then
	command=$line
	else
	command=$(substr "$line" "0" "$space_pos")
	params=$(substr "$line" "$space_pos")
	fi

	if ! type "cmd_$command" 2>/dev/null \| head -1 \| grep -q "function"; then
	echo "Unknown command: '$command'"
	else
	command="cmd_$command"
	$command $params
	fi
	}

	# Checks that a given string looks like a hostname or IPv4 address (starts
	# with an alphanumeric and contains only alphanumeric, '.', or '-'
	# characters).
	check_hostname() {
	expr "$1" : '^[[:alnum:]][-[:alnum:].]*$' > /dev/null
	}

	# Checks that a given string could plausibly be an IPv6 address
	# (hexadecimal, ':', and '.' characters only, followed by an optional zone
	# index consisting of a '%' and a device name).
	check_ipv6() {
	echo "$1" \| /bin/grep -E -q '^[0-9a-fA-F:.]+(%[a-z0-9]+)?$'
	}

	# Checks that a given string starts with an alphanumeric, and contains only
	# alphanumeric and zero or more of ":.~%$^\-"
	check_username() {
	expr "$1" : '^[[:alnum:]][[:alnum:]:.~%$^\-]*$' > /dev/null
	}

	check_digits() {
	expr "$1" : '^[[:digit:]]*$' > /dev/null
	}

	repl() {
	echo "Welcome to crosh, type 'help' for a list of commands."
	if [ "$IS_BASH" != "1" ]; then
	echo "Sorry, line editing and command history disabled due to" \
	"shell limitations."
	fi

	while [ 1 ]; do
	if shell_read "crosh> " LINE_; then
	if [ ! -z "$LINE_" ]; then
	shell_history -s "$LINE_"
	dispatch "$LINE_"
	fi
	else
	echo
	return 1
	fi
	done
	}

	INPUTRC="$(dirname "$0")/inputrc.crosh"
	HISTFILE="$HOME/.crosh_history"
	shell_history -r $HISTFILE

	repl

	shell_history -w $HISTFILE