Merge branch 'tv' into master

42 files changed, 4322 insertions, 0 deletions

diff --git a/tv/configs/AO753.nix b/tv/configs/AO753.nix
new file mode 100644
index 000000000..c103ce2d7
--- /dev/null
+++ b/tv/configs/AO753.nix
@@ -0,0 +1,39 @@
+{ config, pkgs, ... }:
+
+{
+  imports = [
+    ../configs/smartd.nix
+  ];
+
+  boot.loader.grub = {
+    device = "/dev/sda";
+    splashImage = null;
+  };
+
+  boot.initrd.availableKernelModules = [
+    "ahci"
+  ];
+
+  boot.kernelModules = [
+    "kvm-intel"
+    "wl"
+  ];
+
+  boot.extraModulePackages = [
+    config.boot.kernelPackages.broadcom_sta
+  ];
+
+  networking.wireless.enable = true;
+
+  services.logind.extraConfig = ''
+    HandleHibernateKey=ignore
+    HandleLidSwitch=ignore
+    HandlePowerKey=ignore
+    HandleSuspendKey=ignore
+  '';
+
+  nixpkgs.config = {
+    allowUnfree = false;
+    allowUnfreePredicate = (x: pkgs.lib.hasPrefix "broadcom-sta-" x.name);
+  };
+}
diff --git a/tv/configs/CAC-CentOS-7-64bit.nix b/tv/configs/CAC-CentOS-7-64bit.nix
new file mode 100644
index 000000000..168d1d97b
--- /dev/null
+++ b/tv/configs/CAC-CentOS-7-64bit.nix
@@ -0,0 +1,47 @@
+_:
+
+{
+  boot.loader.grub = {
+    device = "/dev/sda";
+    splashImage = null;
+  };
+
+  boot.initrd.availableKernelModules = [
+    "ata_piix"
+    "vmw_pvscsi"
+  ];
+
+  fileSystems."/" = {
+    device = "/dev/centos/root";
+    fsType = "xfs";
+  };
+
+  fileSystems."/boot" = {
+    device = "/dev/sda1";
+    fsType = "xfs";
+  };
+
+  swapDevices = [
+    { device = "/dev/centos/swap"; }
+  ];
+
+  users.extraGroups = {
+    # ● systemd-tmpfiles-setup.service - Create Volatile Files and Directories
+    #    Loaded: loaded (/nix/store/2l33gg7nmncqkpysq9f5fxyhlw6ncm2j-systemd-217/example/systemd/system/systemd-tmpfiles-setup.service)
+    #    Active: failed (Result: exit-code) since Mon 2015-03-16 10:29:18 UTC; 4s ago
+    #      Docs: man:tmpfiles.d(5)
+    #            man:systemd-tmpfiles(8)
+    #   Process: 19272 ExecStart=/nix/store/2l33gg7nmncqkpysq9f5fxyhlw6ncm2j-systemd-217/bin/systemd-tmpfiles --create --remove --boot --exclude-prefix=/dev (code=exited, status=1/FAILURE)
+    #  Main PID: 19272 (code=exited, status=1/FAILURE)
+    #
+    # Mar 16 10:29:17 cd systemd-tmpfiles[19272]: [/usr/lib/tmpfiles.d/legacy.conf:26] Unknown group 'lock'.
+    # Mar 16 10:29:18 cd systemd-tmpfiles[19272]: Two or more conflicting lines for /var/log/journal configured, ignoring.
+    # Mar 16 10:29:18 cd systemd-tmpfiles[19272]: Two or more conflicting lines for /var/log/journal/7b35116927d74ea58785e00b47ac0f0d configured, ignoring.
+    # Mar 16 10:29:18 cd systemd[1]: systemd-tmpfiles-setup.service: main process exited, code=exited, status=1/FAILURE
+    # Mar 16 10:29:18 cd systemd[1]: Failed to start Create Volatile Files and Directories.
+    # Mar 16 10:29:18 cd systemd[1]: Unit systemd-tmpfiles-setup.service entered failed state.
+    # Mar 16 10:29:18 cd systemd[1]: systemd-tmpfiles-setup.service failed.
+    # warning: error(s) occured while switching to the new configuration
+    lock.gid = 10001;
+  };
+}
diff --git a/tv/configs/CAC-Developer-1.nix b/tv/configs/CAC-Developer-1.nix
new file mode 100644
index 000000000..37bc32afb
--- /dev/null
+++ b/tv/configs/CAC-Developer-1.nix
@@ -0,0 +1,6 @@
+_:
+
+{
+  nix.maxJobs = 1;
+  sound.enable = false;
+}
diff --git a/tv/configs/CAC-Developer-2.nix b/tv/configs/CAC-Developer-2.nix
new file mode 100644
index 000000000..fedb808df
--- /dev/null
+++ b/tv/configs/CAC-Developer-2.nix
@@ -0,0 +1,6 @@
+_:
+
+{
+  nix.maxJobs = 2;
+  sound.enable = false;
+}
diff --git a/tv/configs/base.nix b/tv/configs/base.nix
new file mode 100644
index 000000000..06f83ea9e
--- /dev/null
+++ b/tv/configs/base.nix
@@ -0,0 +1,188 @@
+{ config, lib, pkgs, ... }:
+
+with builtins;
+with lib;
+
+let
+  # "7.4.335" -> "74"
+  majmin = x: concatStrings (take 2 (splitString "." x));
+in
+
+{
+  krebs.enable = true;
+  krebs.search-domain = "retiolum";
+
+  networking.hostName = config.krebs.build.host.name;
+
+  imports = [
+    {
+      users.extraUsers =
+        mapAttrs (_: h: { hashedPassword = h; })
+                 (import /root/src/secrets/hashedPasswords.nix);
+    }
+    {
+      users.defaultUserShell = "/run/current-system/sw/bin/bash";
+      users.mutableUsers = false;
+    }
+    {
+      users.extraUsers = {
+        root = {
+          openssh.authorizedKeys.keys = [
+            config.krebs.users.tv.pubkey
+          ];
+        };
+        tv = {
+          uid = 1337;
+          group = "users";
+          home = "/home/tv";
+          createHome = true;
+          useDefaultShell = true;
+          extraGroups = [
+            "audio"
+            "video"
+            "wheel"
+          ];
+          openssh.authorizedKeys.keys = [
+            config.krebs.users.tv.pubkey
+          ];
+        };
+      };
+    }
+    {
+      security.sudo.extraConfig = ''
+        Defaults mailto="${config.krebs.users.tv.mail}"
+      '';
+      time.timeZone = "Europe/Berlin";
+    }
+    {
+      # TODO check if both are required:
+      nix.chrootDirs = [ "/etc/protocols" pkgs.iana_etc.outPath ];
+
+      nix.trustedBinaryCaches = [
+        "https://cache.nixos.org"
+        "http://cache.nixos.org"
+        "http://hydra.nixos.org"
+      ];
+
+      nix.useChroot = true;
+    }
+    {
+      # oldvim
+      environment.systemPackages = with pkgs; [
+        vim
+      ];
+
+      environment.etc."vim/vimrc".text = ''
+        set nocp
+      '';
+
+      environment.etc."vim/vim${majmin pkgs.vim.version}".source =
+          "${pkgs.vim}/share/vim/vim${majmin pkgs.vim.version}";
+
+      # multiple-definition-problem when defining environment.variables.EDITOR
+      environment.extraInit = ''
+        EDITOR=vim
+      '';
+
+      environment.variables.VIM = "/etc/vim";
+    }
+    {
+      environment.systemPackages = with pkgs; [
+        rxvt_unicode.terminfo
+      ];
+
+      environment.shellAliases = {
+        # alias cal='cal -m3'
+        gp = "${pkgs.pari}/bin/gp -q";
+        df = "df -h";
+        du = "du -h";
+        # alias grep='grep --color=auto'
+
+        # TODO alias cannot contain #\'
+        # "ps?" = "ps ax | head -n 1;ps ax | fgrep -v ' grep --color=auto ' | grep";
+
+        # alias la='ls -lA'
+        lAtr = "ls -lAtr";
+        # alias ll='ls -l'
+        ls = "ls -h --color=auto --group-directories-first";
+        # alias vim='vim -p'
+        # alias vi='vim'
+        # alias view='vim -R'
+        dmesg = "dmesg -L --reltime";
+      };
+
+      programs.bash = {
+        interactiveShellInit = ''
+          HISTCONTROL='erasedups:ignorespace'
+          HISTSIZE=65536
+          HISTFILESIZE=$HISTSIZE
+
+          shopt -s checkhash
+          shopt -s histappend histreedit histverify
+          shopt -s no_empty_cmd_completion
+          complete -d cd
+
+          ${readFile ./bash_completion.sh}
+
+          # TODO source bridge
+        '';
+        promptInit = ''
+          case $UID in
+            0)
+              PS1='\[\e[1;31m\]\w\[\e[0m\] '
+              ;;
+            1337)
+              PS1='\[\e[1;32m\]\w\[\e[0m\] '
+              ;;
+            *)
+              PS1='\[\e[1;35m\]\u \[\e[1;32m\]\w\[\e[0m\] '
+              ;;
+          esac
+          if test -n "$SSH_CLIENT"; then
+            PS1='\[\e[35m\]\h'" $PS1"
+          fi
+          if test -n "$SSH_AGENT_PID"; then
+            PS1="ssh-agent[$SSH_AGENT_PID] $PS1"
+          fi
+        '';
+      };
+
+      programs.ssh.startAgent = false;
+    }
+
+    {
+      nixpkgs.config.packageOverrides = pkgs:
+        {
+          nano = pkgs.runCommand "empty" {} "mkdir -p $out";
+        };
+
+      services.cron.enable = false;
+      services.nscd.enable = false;
+      services.ntp.enable = false;
+    }
+
+    {
+      boot.kernel.sysctl = {
+        # Enable IPv6 Privacy Extensions
+        "net.ipv6.conf.all.use_tempaddr" = 2;
+        "net.ipv6.conf.default.use_tempaddr" = 2;
+      };
+    }
+
+    {
+      services.openssh = {
+        enable = true;
+        hostKeys = [
+          { type = "ed25519"; path = "/etc/ssh/ssh_host_ed25519_key"; }
+        ];
+      };
+    }
+
+    {
+      # TODO: exim
+      security.setuidPrograms = [
+        "sendmail"  # for sudo
+      ];
+    }
+  ];
+}
diff --git a/tv/configs/bash_completion.sh b/tv/configs/bash_completion.sh
new file mode 100644
index 000000000..537484fb9
--- /dev/null
+++ b/tv/configs/bash_completion.sh
@@ -0,0 +1,779 @@
+
+# Expand variable starting with tilde (~)
+# We want to expand ~foo/... to /home/foo/... to avoid problems when
+# word-to-complete starting with a tilde is fed to commands and ending up
+# quoted instead of expanded.
+# Only the first portion of the variable from the tilde up to the first slash
+# (~../) is expanded.  The remainder of the variable, containing for example
+# a dollar sign variable ($) or asterisk (*) is not expanded.
+# Example usage:
+#
+#    $ v="~"; __expand_tilde_by_ref v; echo "$v"
+#
+# Example output:
+#
+#       v                  output
+#    --------         ----------------
+#    ~                /home/user
+#    ~foo/bar         /home/foo/bar
+#    ~foo/$HOME       /home/foo/$HOME
+#    ~foo/a  b        /home/foo/a  b
+#    ~foo/*           /home/foo/*
+#
+# @param $1  Name of variable (not the value of the variable) to expand
+__expand_tilde_by_ref()
+{
+    # Does $1 start with tilde (~)?
+    if [[ ${!1} == \~* ]]; then
+        # Does $1 contain slash (/)?
+        if [[ ${!1} == */* ]]; then
+            # Yes, $1 contains slash;
+            # 1: Remove * including and after first slash (/), i.e. "~a/b"
+            #    becomes "~a".  Double quotes allow eval.
+            # 2: Remove * before the first slash (/), i.e. "~a/b"
+            #    becomes "b".  Single quotes prevent eval.
+            #       +-----1----+ +---2----+
+            eval $1="${!1/%\/*}"/'${!1#*/}'
+        else
+            # No, $1 doesn't contain slash
+            eval $1="${!1}"
+        fi
+    fi
+} # __expand_tilde_by_ref()
+
+
+# Get the word to complete.
+# This is nicer than ${COMP_WORDS[$COMP_CWORD]}, since it handles cases
+# where the user is completing in the middle of a word.
+# (For example, if the line is "ls foobar",
+# and the cursor is here -------->   ^
+# @param $1 string  Characters out of $COMP_WORDBREAKS which should NOT be
+#     considered word breaks. This is useful for things like scp where
+#     we want to return host:path and not only path, so we would pass the
+#     colon (:) as $1 in this case.
+# @param $2 integer  Index number of word to return, negatively offset to the
+#     current word (default is 0, previous is 1), respecting the exclusions
+#     given at $1.  For example, `_get_cword "=:" 1' returns the word left of
+#     the current word, respecting the exclusions "=:".
+# @deprecated  Use `_get_comp_words_by_ref cur' instead
+# @see _get_comp_words_by_ref()
+_get_cword()
+{
+    local LC_CTYPE=C
+    local cword words
+    __reassemble_comp_words_by_ref "$1" words cword
+
+    # return previous word offset by $2
+    if [[ ${2//[^0-9]/} ]]; then
+        printf "%s" "${words[cword-$2]}"
+    elif [[ "${#words[cword]}" -eq 0 || "$COMP_POINT" == "${#COMP_LINE}" ]]; then
+        printf "%s" "${words[cword]}"
+    else
+        local i
+        local cur="$COMP_LINE"
+        local index="$COMP_POINT"
+        for (( i = 0; i <= cword; ++i )); do
+            while [[
+                # Current word fits in $cur?
+                "${#cur}" -ge ${#words[i]} &&
+                # $cur doesn't match cword?
+                "${cur:0:${#words[i]}}" != "${words[i]}"
+            ]]; do
+                # Strip first character
+                cur="${cur:1}"
+                # Decrease cursor position
+                ((index--))
+            done
+
+            # Does found word matches cword?
+            if [[ "$i" -lt "$cword" ]]; then
+                # No, cword lies further;
+                local old_size="${#cur}"
+                cur="${cur#${words[i]}}"
+                local new_size="${#cur}"
+                index=$(( index - old_size + new_size ))
+            fi
+        done
+
+        if [[ "${words[cword]:0:${#cur}}" != "$cur" ]]; then
+            # We messed up! At least return the whole word so things
+            # keep working
+            printf "%s" "${words[cword]}"
+        else
+            printf "%s" "${cur:0:$index}"
+        fi
+    fi
+} # _get_cword()
+
+
+# Get word previous to the current word.
+# This is a good alternative to `prev=${COMP_WORDS[COMP_CWORD-1]}' because bash4
+# will properly return the previous word with respect to any given exclusions to
+# COMP_WORDBREAKS.
+# @deprecated  Use `_get_comp_words_by_ref cur prev' instead
+# @see _get_comp_words_by_ref()
+#
+_get_pword()
+{
+    if [[ $COMP_CWORD -ge 1 ]]; then
+        _get_cword "${@:-}" 1
+    fi
+}
+
+
+
+# Complete variables.
+# @return  True (0) if variables were completed,
+#          False (> 0) if not.
+_variables()
+{
+    if [[ $cur =~ ^(\$\{?)([A-Za-z0-9_]*)$ ]]; then
+        [[ $cur == *{* ]] && local suffix=} || local suffix=
+        COMPREPLY+=( $( compgen -P ${BASH_REMATCH[1]} -S "$suffix" -v -- \
+            "${BASH_REMATCH[2]}" ) )
+        return 0
+    fi
+    return 1
+}
+
+# Assign variable one scope above the caller
+# Usage: local "$1" && _upvar $1 "value(s)"
+# Param: $1  Variable name to assign value to
+# Param: $*  Value(s) to assign.  If multiple values, an array is
+#            assigned, otherwise a single value is assigned.
+# NOTE: For assigning multiple variables, use '_upvars'.  Do NOT
+#       use multiple '_upvar' calls, since one '_upvar' call might
+#       reassign a variable to be used by another '_upvar' call.
+# See: http://fvue.nl/wiki/Bash:_Passing_variables_by_reference
+_upvar()
+{
+    if unset -v "$1"; then           # Unset & validate varname
+        if (( $# == 2 )); then
+            eval $1=\"\$2\"          # Return single value
+        else
+            eval $1=\(\"\${@:2}\"\)  # Return array
+        fi
+    fi
+}
+
+# Assign variables one scope above the caller
+# Usage: local varname [varname ...] &&
+#        _upvars [-v varname value] | [-aN varname [value ...]] ...
+# Available OPTIONS:
+#     -aN  Assign next N values to varname as array
+#     -v   Assign single value to varname
+# Return: 1 if error occurs
+# See: http://fvue.nl/wiki/Bash:_Passing_variables_by_reference
+_upvars()
+{
+    if ! (( $# )); then
+        echo "${FUNCNAME[0]}: usage: ${FUNCNAME[0]} [-v varname"\
+            "value] | [-aN varname [value ...]] ..." 1>&2
+        return 2
+    fi
+    while (( $# )); do
+        case $1 in
+            -a*)
+                # Error checking
+                [[ ${1#-a} ]] || { echo "bash: ${FUNCNAME[0]}: \`$1': missing"\
+                    "number specifier" 1>&2; return 1; }
+                printf %d "${1#-a}" &> /dev/null || { echo "bash:"\
+                    "${FUNCNAME[0]}: \`$1': invalid number specifier" 1>&2
+                    return 1; }
+                # Assign array of -aN elements
+                [[ "$2" ]] && unset -v "$2" && eval $2=\(\"\${@:3:${1#-a}}\"\) &&
+                shift $((${1#-a} + 2)) || { echo "bash: ${FUNCNAME[0]}:"\
+                    "\`$1${2+ }$2': missing argument(s)" 1>&2; return 1; }
+                ;;
+            -v)
+                # Assign single value
+                [[ "$2" ]] && unset -v "$2" && eval $2=\"\$3\" &&
+                shift 3 || { echo "bash: ${FUNCNAME[0]}: $1: missing"\
+                "argument(s)" 1>&2; return 1; }
+                ;;
+            *)
+                echo "bash: ${FUNCNAME[0]}: $1: invalid option" 1>&2
+                return 1 ;;
+        esac
+    done
+}
+
+# @param $1 exclude  Characters out of $COMP_WORDBREAKS which should NOT be
+#     considered word breaks. This is useful for things like scp where
+#     we want to return host:path and not only path, so we would pass the
+#     colon (:) as $1 in this case.
+# @param $2 words  Name of variable to return words to
+# @param $3 cword  Name of variable to return cword to
+# @param $4 cur  Name of variable to return current word to complete to
+# @see __reassemble_comp_words_by_ref()
+__get_cword_at_cursor_by_ref()
+{
+    local cword words=()
+    __reassemble_comp_words_by_ref "$1" words cword
+
+    local i cur index=$COMP_POINT lead=${COMP_LINE:0:$COMP_POINT}
+    # Cursor not at position 0 and not leaded by just space(s)?
+    if [[ $index -gt 0 && ( $lead && ${lead//[[:space:]]} ) ]]; then
+        cur=$COMP_LINE
+        for (( i = 0; i <= cword; ++i )); do
+            while [[
+                # Current word fits in $cur?
+                ${#cur} -ge ${#words[i]} &&
+                # $cur doesn't match cword?
+                "${cur:0:${#words[i]}}" != "${words[i]}"
+            ]]; do
+                # Strip first character
+                cur="${cur:1}"
+                # Decrease cursor position
+                ((index--))
+            done
+
+            # Does found word match cword?
+            if [[ $i -lt $cword ]]; then
+                # No, cword lies further;
+                local old_size=${#cur}
+                cur="${cur#"${words[i]}"}"
+                local new_size=${#cur}
+                index=$(( index - old_size + new_size ))
+            fi
+        done
+        # Clear $cur if just space(s)
+        [[ $cur && ! ${cur//[[:space:]]} ]] && cur=
+        # Zero $index if negative
+        [[ $index -lt 0 ]] && index=0
+    fi
+
+    local "$2" "$3" "$4" && _upvars -a${#words[@]} $2 "${words[@]}" \
+        -v $3 "$cword" -v $4 "${cur:0:$index}"
+}
+
+# Reassemble command line words, excluding specified characters from the
+# list of word completion separators (COMP_WORDBREAKS).
+# @param $1 chars  Characters out of $COMP_WORDBREAKS which should
+#     NOT be considered word breaks. This is useful for things like scp where
+#     we want to return host:path and not only path, so we would pass the
+#     colon (:) as $1 here.
+# @param $2 words  Name of variable to return words to
+# @param $3 cword  Name of variable to return cword to
+#
+__reassemble_comp_words_by_ref()
+{
+    local exclude i j line ref
+    # Exclude word separator characters?
+    if [[ $1 ]]; then
+        # Yes, exclude word separator characters;
+        # Exclude only those characters, which were really included
+        exclude="${1//[^$COMP_WORDBREAKS]}"
+    fi
+
+    # Default to cword unchanged
+    eval $3=$COMP_CWORD
+    # Are characters excluded which were former included?
+    if [[ $exclude ]]; then
+        # Yes, list of word completion separators has shrunk;
+        line=$COMP_LINE
+        # Re-assemble words to complete
+        for (( i=0, j=0; i < ${#COMP_WORDS[@]}; i++, j++)); do
+            # Is current word not word 0 (the command itself) and is word not
+            # empty and is word made up of just word separator characters to
+            # be excluded and is current word not preceded by whitespace in
+            # original line?
+            while [[ $i -gt 0 && ${COMP_WORDS[$i]} == +([$exclude]) ]]; do
+                # Is word separator not preceded by whitespace in original line
+                # and are we not going to append to word 0 (the command
+                # itself), then append to current word.
+                [[ $line != [$' \t']* ]] && (( j >= 2 )) && ((j--))
+                # Append word separator to current or new word
+                ref="$2[$j]"
+                eval $2[$j]=\${!ref}\${COMP_WORDS[i]}
+                # Indicate new cword
+                [[ $i == $COMP_CWORD ]] && eval $3=$j
+                # Remove optional whitespace + word separator from line copy
+                line=${line#*"${COMP_WORDS[$i]}"}
+                # Start new word if word separator in original line is
+                # followed by whitespace.
+                [[ $line == [$' \t']* ]] && ((j++))
+                # Indicate next word if available, else end *both* while and
+                # for loop
+                (( $i < ${#COMP_WORDS[@]} - 1)) && ((i++)) || break 2
+            done
+            # Append word to current word
+            ref="$2[$j]"
+            eval $2[$j]=\${!ref}\${COMP_WORDS[i]}
+            # Remove optional whitespace + word from line copy
+            line=${line#*"${COMP_WORDS[i]}"}
+            # Indicate new cword
+            [[ $i == $COMP_CWORD ]] && eval $3=$j
+        done
+        [[ $i == $COMP_CWORD ]] && eval $3=$j
+    else
+        # No, list of word completions separators hasn't changed;
+        eval $2=\( \"\${COMP_WORDS[@]}\" \)
+    fi
+} # __reassemble_comp_words_by_ref()
+
+
+# If the word-to-complete contains a colon (:), left-trim COMPREPLY items with
+# word-to-complete.
+# With a colon in COMP_WORDBREAKS, words containing
+# colons are always completed as entire words if the word to complete contains
+# a colon.  This function fixes this, by removing the colon-containing-prefix
+# from COMPREPLY items.
+# The preferred solution is to remove the colon (:) from COMP_WORDBREAKS in
+# your .bashrc:
+#
+#    # Remove colon (:) from list of word completion separators
+#    COMP_WORDBREAKS=${COMP_WORDBREAKS//:}
+#
+# See also: Bash FAQ - E13) Why does filename completion misbehave if a colon
+# appears in the filename? - http://tiswww.case.edu/php/chet/bash/FAQ
+# @param $1 current word to complete (cur)
+# @modifies global array $COMPREPLY
+#
+__ltrim_colon_completions()
+{
+    if [[ "$1" == *:* && "$COMP_WORDBREAKS" == *:* ]]; then
+        # Remove colon-word prefix from COMPREPLY items
+        local colon_word=${1%"${1##*:}"}
+        local i=${#COMPREPLY[*]}
+        while [[ $((--i)) -ge 0 ]]; do
+            COMPREPLY[$i]=${COMPREPLY[$i]#"$colon_word"}
+        done
+    fi
+} # __ltrim_colon_completions()
+
+
+# NOTE: Using this function as a helper function is deprecated.  Use
+#       `_known_hosts_real' instead.
+_known_hosts()
+{
+    local cur prev words cword
+    _init_completion -n : || return
+
+    # NOTE: Using `_known_hosts' as a helper function and passing options
+    #       to `_known_hosts' is deprecated: Use `_known_hosts_real' instead.
+    local options
+    [[ "$1" == -a || "$2" == -a ]] && options=-a
+    [[ "$1" == -c || "$2" == -c ]] && options+=" -c"
+    _known_hosts_real $options -- "$cur"
+} # _known_hosts()
+
+
+# Helper function for completing _known_hosts.
+# This function performs host completion based on ssh's config and known_hosts
+# files, as well as hostnames reported by avahi-browse if
+# COMP_KNOWN_HOSTS_WITH_AVAHI is set to a non-empty value.  Also hosts from
+# HOSTFILE (compgen -A hostname) are added, unless
+# COMP_KNOWN_HOSTS_WITH_HOSTFILE is set to an empty value.
+# Usage: _known_hosts_real [OPTIONS] CWORD
+# Options:  -a