From a206271460ce49e842b1b410c0424b8c9a0a3d14 Mon Sep 17 00:00:00 2001
From: Nuno Goncalves <nunojpg@gmail.com>
Date: Sat, 12 Jun 2021 04:03:25 +0200
Subject: 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 $HOME/.ssh/). This would trigger a error.
Creating the directory would be a option, but it
usually will not make sense to do so because it means
the user doesn't have ssh keys or config.
Signed-off-by: Nuno Goncalves <nunojpg@gmail.com>
* ssh-agent: adds lazy option to disable key loading on start
Option is documented on updated README.md
Signed-off-by: Nuno Goncalves <nunojpg@gmail.com>
* ssh-agent: simplify agent-forwarding checking
Signed-off-by: Nuno Goncalves <nunojpg@gmail.com>
Co-authored-by: Robby Russell <robby@planetargon.com>
---
plugins/ssh-agent/README.md | 12 ++++++++++--
plugins/ssh-agent/ssh-agent.plugin.zsh | 29 +++++++++++++++++++++--------
2 files changed, 31 insertions(+), 10 deletions(-)
(limited to 'plugins/ssh-agent')
diff --git a/plugins/ssh-agent/README.md b/plugins/ssh-agent/README.md
index 8765a9c7e..aa96f9cc9 100644
--- a/plugins/ssh-agent/README.md
+++ b/plugins/ssh-agent/README.md
@@ -19,9 +19,17 @@ To enable **agent forwarding support** add the following to your zshrc file:
zstyle :omz:plugins:ssh-agent agent-forwarding on
```
-----
+To **NOT load any identities on start** use the `lazy` style.
+This is particularly usefull when combined with the AddKeysToAgent
+(available from OpenSSH 7.2), since it allows to enter the password only
+on first use.
+
+```zsh
+zstyle :omz:plugins:ssh-agent lazy yes
+```
-To **load multiple identities** use the `identities` style, For example:
+To **load multiple identities** use the `identities` style. This have no
+effect if `lazy` is enabled.
```zsh
zstyle :omz:plugins:ssh-agent identities id_rsa id_rsa2 id_github
diff --git a/plugins/ssh-agent/ssh-agent.plugin.zsh b/plugins/ssh-agent/ssh-agent.plugin.zsh
index d45406f63..494cf1393 100644
--- a/plugins/ssh-agent/ssh-agent.plugin.zsh
+++ b/plugins/ssh-agent/ssh-agent.plugin.zsh
@@ -1,4 +1,16 @@
-typeset _agent_forwarding _ssh_env_cache
+lockdir=/tmp/oh-my-zsh-ssh-agent.lock
+
+while true; do
+ if mkdir "$lockdir" 2>/dev/null
+ then # directory did not exist, but was created successfully
+ trap 'rm -rf "$lockdir"' 0 # remove directory when script finishes
+ break # continue with script
+ else
+ sleep 0.1 # sleep for 0.2 and try again
+ fi
+done
+
+typeset _ssh_env_cache
function _start_agent() {
local lifetime
@@ -56,10 +68,7 @@ function _add_identities() {
# Get the filename to store/lookup the environment from
_ssh_env_cache="$HOME/.ssh/environment-$SHORT_HOST"
-# test if agent-forwarding is enabled
-zstyle -b :omz:plugins:ssh-agent agent-forwarding _agent_forwarding
-
-if [[ $_agent_forwarding == "yes" && -n "$SSH_AUTH_SOCK" ]]; then
+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
@@ -73,12 +82,16 @@ elif [[ -f "$_ssh_env_cache" ]]; then
ps $FILTER | grep ssh-agent | grep -q $SSH_AGENT_PID || {
_start_agent
}
-else
+elif [[ -d $HOME/.ssh ]]; then
_start_agent
fi
-_add_identities
+if ! zstyle -t :omz:plugins:ssh-agent lazy; then
+ _add_identities
+fi
# tidy up after ourselves
-unset _agent_forwarding _ssh_env_cache
+unset _ssh_env_cache
unfunction _start_agent _add_identities
+
+rm -rf "$lockdir"
--
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