Replace symlinks with actual binaries

We had `gitlab-shell-authorized-keys-check` and
`gitlab-shell-authorized-principals-check` as symlinks to
`gitlab-shell` before.

We determine the `Command` and `CommandArgs` that we build based
on the `Name` of the `Executable`. We also use that to know which
fallback ruby executable should we fallback to. We use
`os.Executable()` to do that.

`os.Executable()` behaves differently depending on OS. It may
return the symlink or the target's name. That can result to a
buggy behavior.

The fix is to create binaries for each instead of using a symlink.
That way we don't need to rely on `os.Executable()` to get the name.
We pass the `Name` of the executable instead.

1 files changed, 46 insertions, 0 deletions

diff --git a/go/cmd/gitlab-shell-authorized-keys-check/main.go b/go/cmd/gitlab-shell-authorized-keys-check/main.go
new file mode 100644
index 0000000..2bde63d
--- /dev/null
+++ b/go/cmd/gitlab-shell-authorized-keys-check/main.go
@@ -0,0 +1,46 @@
+package main
+
+import (
+	"fmt"
+	"os"
+
+	"gitlab.com/gitlab-org/gitlab-shell/go/internal/command"
+	"gitlab.com/gitlab-org/gitlab-shell/go/internal/command/readwriter"
+	"gitlab.com/gitlab-org/gitlab-shell/go/internal/config"
+	"gitlab.com/gitlab-org/gitlab-shell/go/internal/executable"
+)
+
+func main() {
+	readWriter := &readwriter.ReadWriter{
+		Out:    os.Stdout,
+		In:     os.Stdin,
+		ErrOut: os.Stderr,
+	}
+
+	executable, err := executable.New(executable.AuthorizedKeysCheck)
+	if err != nil {
+		fmt.Fprintln(readWriter.ErrOut, "Failed to determine executable, exiting")
+		os.Exit(1)
+	}
+
+	config, err := config.NewFromDir(executable.RootDir)
+	if err != nil {
+		fmt.Fprintln(readWriter.ErrOut, "Failed to read config, exiting")
+		os.Exit(1)
+	}
+
+	cmd, err := command.New(executable, os.Args[1:], config, readWriter)
+	if err != nil {
+		// For now this could happen if `SSH_CONNECTION` is not set on
+		// the environment
+		fmt.Fprintf(readWriter.ErrOut, "%v\n", err)
+		os.Exit(1)
+	}
+
+	// The command will write to STDOUT on execution or replace the current
+	// process in case of the `fallback.Command`
+	if err = cmd.Execute(); err != nil {
+		fmt.Fprintf(readWriter.ErrOut, "%v\n", err)
+		os.Exit(1)
+	}
+}