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ohmyzsh/plugins/ssh-agent/ssh-agent.plugin.zsh
Nuno Goncalves a206271460
ssh-agent: improvements (#6309)
* ssh-agent: lock this script with a mkdir style mutex

This script is a kind of singleton pattern and is not reentrant.
If several shells are oppened in a fast sequence, then several
independent ssh-agents would be created, which is not acceptable.
A mutex is required.

Signed-off-by: Nuno Goncalves <nunojpg@gmail.com>

* ssh-agent: only start agent if .ssh dir exists

To use the same profile system-wide, it might happen
that the .ssh directory does not exist
(typically $HOME/.ssh/). This would trigger a error.

Creating the directory would be a option, but it
usually will not make sense to do so because it means
the user doesn't have ssh keys or config.

Signed-off-by: Nuno Goncalves <nunojpg@gmail.com>

* ssh-agent: adds lazy option to disable key loading on start

Option is documented on updated README.md

Signed-off-by: Nuno Goncalves <nunojpg@gmail.com>

* ssh-agent: simplify agent-forwarding checking

Signed-off-by: Nuno Goncalves <nunojpg@gmail.com>

Co-authored-by: Robby Russell <robby@planetargon.com>
2021-06-11 19:03:25 -07:00

98 lines
2.7 KiB
Bash

lockdir=/tmp/oh-my-zsh-ssh-agent.lock
while true; do
if mkdir "$lockdir" 2>/dev/null
then # directory did not exist, but was created successfully
trap 'rm -rf "$lockdir"' 0 # remove directory when script finishes
break # continue with script
else
sleep 0.1 # sleep for 0.2 and try again
fi
done
typeset _ssh_env_cache
function _start_agent() {
local lifetime
zstyle -s :omz:plugins:ssh-agent lifetime lifetime
# start ssh-agent and setup environment
echo Starting ssh-agent...
ssh-agent -s ${lifetime:+-t} ${lifetime} | sed 's/^echo/#echo/' >! $_ssh_env_cache
chmod 600 $_ssh_env_cache
. $_ssh_env_cache > /dev/null
}
function _add_identities() {
local id line sig lines
local -a identities loaded_sigs loaded_ids not_loaded
zstyle -a :omz:plugins:ssh-agent identities identities
# check for .ssh folder presence
if [[ ! -d $HOME/.ssh ]]; then
return
fi
# add default keys if no identities were set up via zstyle
# this is to mimic the call to ssh-add with no identities
if [[ ${#identities} -eq 0 ]]; then
# key list found on `ssh-add` man page's DESCRIPTION section
for id in id_rsa id_dsa id_ecdsa id_ed25519 identity; do
# check if file exists
[[ -f "$HOME/.ssh/$id" ]] && identities+=$id
done
fi
# get list of loaded identities' signatures and filenames
if lines=$(ssh-add -l); then
for line in ${(f)lines}; do
loaded_sigs+=${${(z)line}[2]}
loaded_ids+=${${(z)line}[3]}
done
fi
# add identities if not already loaded
for id in $identities; do
# check for filename match, otherwise try for signature match
if [[ ${loaded_ids[(I)$HOME/.ssh/$id]} -le 0 ]]; then
sig="$(ssh-keygen -lf "$HOME/.ssh/$id" | awk '{print $2}')"
[[ ${loaded_sigs[(I)$sig]} -le 0 ]] && not_loaded+="$HOME/.ssh/$id"
fi
done
local args
zstyle -a :omz:plugins:ssh-agent ssh-add-args args
[[ -n "$not_loaded" ]] && ssh-add "${args[@]}" ${^not_loaded}
}
# Get the filename to store/lookup the environment from
_ssh_env_cache="$HOME/.ssh/environment-$SHORT_HOST"
if zstyle -t :omz:plugins:ssh-agent agent-forwarding && [[ -n "$SSH_AUTH_SOCK" ]]; then
# Add a nifty symlink for screen/tmux if agent forwarding
[[ -L $SSH_AUTH_SOCK ]] || ln -sf "$SSH_AUTH_SOCK" /tmp/ssh-agent-$USERNAME-screen
elif [[ -f "$_ssh_env_cache" ]]; then
# Source SSH settings, if applicable
. $_ssh_env_cache > /dev/null
if [[ $USERNAME == "root" ]]; then
FILTER="ax"
else
FILTER="x"
fi
ps $FILTER | grep ssh-agent | grep -q $SSH_AGENT_PID || {
_start_agent
}
elif [[ -d $HOME/.ssh ]]; then
_start_agent
fi
if ! zstyle -t :omz:plugins:ssh-agent lazy; then
_add_identities
fi
# tidy up after ourselves
unset _ssh_env_cache
unfunction _start_agent _add_identities
rm -rf "$lockdir"