ssh: Try to save and restore SSH environment

This allows ZSH sessions inside of screen(1) to pick up the current SSH
agent connection, for example.

diff --git a/default_plugins/ssh/ssh.zshrc b/default_plugins/ssh/ssh.zshrc
index 8d22ae2a074fdf762c1bb1b666e4132d01ce0cc3..ce2a877d086258ae168b3b93e1e6994989357c51 100644 (file)
--- a/default_plugins/ssh/ssh.zshrc
+++ b/default_plugins/ssh/ssh.zshrc
@@ -11,3 +11,37 @@ _ax_ssh_prompt() {
 
 ax_logname_prompt_functions=($ax_logname_prompt_functions _ax_ssh_prompt)
 ax_hostname_prompt_functions=($ax_hostname_prompt_functions _ax_ssh_prompt)
+
+# Validate SSH_AUTH_SOCK: Inside of screen(1) sessions for example, the socket
+# file becomes invalid when the session has been disconnected.
+[[ ! -r "$SSH_AUTH_SOCK" ]] && unset SSH_AUTH_SOCK
+
+# Save SSH environment when available:
+if [[ -n "$SSH_AUTH_SOCK" ]]; then
+       # Save current environment when no state exists or is invalid.
+       if [[ -r "$XDG_RUNTIME_DIR/ssh-env.sh" ]]; then
+               (
+                       source "$XDG_RUNTIME_DIR/ssh-env.sh"
+                       if [[ -z "$SSH_AUTH_SOCK" || ! -r "$SSH_AUTH_SOCK" ]]; then
+                               # Content is invalid, remove state file!
+                               rm -f "$XDG_RUNTIME_DIR/ssh-env.sh"
+                       fi
+               )
+       fi
+       if [[ ! -r "$XDG_RUNTIME_DIR/ssh-env.sh" ]]; then
+               # No state file exists, create a new one:
+               echo "SSH_AUTH_SOCK=\"$SSH_AUTH_SOCK\"" >"$XDG_RUNTIME_DIR/ssh-env.sh"
+               echo "export SSH_AUTH_SOCK" >>"$XDG_RUNTIME_DIR/ssh-env.sh"
+       fi
+fi
+
+# Restore SSH environment when not set but available:
+if [[ -z "$SSH_AUTH_SOCK" && -r "$XDG_RUNTIME_DIR/ssh-env.sh" ]]; then
+       # Try to recover known good environment ...
+       source "$XDG_RUNTIME_DIR/ssh-env.sh"
+       if [[ ! -r "$SSH_AUTH_SOCK" ]]; then
+               # Clean up!
+               unset SSH_AUTH_SOCK
+               rm -f "$XDG_RUNTIME_DIR/ssh-env.sh"
+       fi
+fi