Feat: adds sshdir command

2 files changed, 86 insertions, 0 deletions

diff --git a/ChangeLog.md b/ChangeLog.md
index 14e33d4..b99c8cf 100644
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -1,5 +1,19 @@
 # ChangeLog
 
+## 0.4.0 - Unreleased
+
+* Adds `kvmx sshdir` action, which SSH's to the guest and changes to a given
+  folder. If no arguments are given, it tries to change to the equivalent
+  folder in the guest, so it can be a way to "cd" to the same directory but
+  inside the guest.
+
+  If the folder in the host is also mounted in the guest in a similar
+  mountpoint, it's a handy way to move to the same folder, but inside the
+  guest.
+
+  For folders inside $HOME, user name conversion is automatically done since
+  the user inside the guest might not match the user in the host.
+
 ## 0.3.0 - 2024-09-19
 
 * Increase the maximum number of shared folders to avoid error in when KVMX
diff --git a/kvmx b/kvmx
index f00d3f7..a2578d8 100755
--- a/kvmx
+++ b/kvmx
@@ -965,6 +965,78 @@ function kvmx_ssh {
   $ssh_env $SSH_COMMAND -p $SSH 127.0.0.1 $*
 }
 
+# Log into the guest using SSH and cd to a given folder
+#
+# If no arguments are given, it tries to change to the equivalent folder in the
+# guest, so it can be a way to "cd" to the corresponding directory but inside
+# the guest.
+#
+# If the folder in the host is also mounted in the guest in a similar
+# mountpoint, it's a handy way to move to the same folder, but inside the
+# guest.
+#
+# For folders inside $HOME, user name conversion is automatically done since
+# the user inside the guest might not match the user in the host.
+#
+# There are a number of ways this can be done:
+#
+# 1. Trying to move to a folder, and then exec a login shell, which don't
+#    always work.
+#
+# 2. Setting a special environment variable which is interpreted by the shell
+#    startup script and then changes to the requested folder upon login.
+#    Variable passing can happen directly through command invocation in
+#    the remote host, or using SSH's SendEnv and AcceptEnv, but this last
+#    method involves server-side configuration.
+#
+# Ideally, all approaches should be implemented, and KVMX could choose the
+# best one opportunistially, or could have a configuration option to choose,
+# defaulting to the one which could work for most cases.
+#
+function kvmx_sshdir {
+  if [ "$ssh_support" != "y" ]; then
+    echo "$BASENAME: SSH support for $VM is disabled"
+    exit 1
+  fi
+
+  if ! kvmx_running || kvmx_suspended; then
+    echo "$BASENAME: $VM not running, trying to start it..."
+    kvmx up $VM || exit 1
+    #kvmx_up || exit 1
+    #echo "$BASENAME: guest $VM is not running"
+    #exit 1
+  fi
+
+  DEST="$1"
+
+  # Defaults to the current folder
+  if [ -z "$DEST" ]; then
+    DEST="`pwd`"
+
+    # Fix ~/ path
+    if echo $DEST | grep -q -e "^$HOME"; then
+      DEST="$(echo $DEST | sed -e "s|^$HOME|/home/$SSH_LOGIN|")"
+    fi
+  fi
+
+  # Get the SSH configuration
+  SSH="`cat $SSHFILE`"
+
+  # Implementation using approach 1: change to folder and invoke the login shell
+  #
+  # References and discussion:
+  #
+  # * https://serverfault.com/questions/167416/how-can-i-automatically-change-directory-on-ssh-login
+  # * https://stackoverflow.com/questions/626533/how-can-i-ssh-directly-to-a-particular-directory#626670
+  # * https://unix.stackexchange.com/questions/86941/how-to-ssh-into-a-specific-directory
+  #
+  $ssh_env $SSH_COMMAND -t -p $SSH 127.0.0.1 "cd $DEST && exec \$SHELL --login"
+
+  # Implementation using approach 2, with a special environment variable
+  # STARTUP_FOLDER, which needs to be supported by the shell startup scripts
+  #$ssh_env $SSH_COMMAND -t -p $SSH 127.0.0.1 "export STARTUP_FOLDER=$DEST && exec \$SHELL --login"
+}
+
 # Enhanced SSH login into the guest
 function kvmx_login {
   # This allows the usage of a custom login command