From b8d2aa264de4ebff472698347588f36ed6d4a3e8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ludovic=20Court=C3=A8s?= <ludo@gnu.org>
Date: Tue, 19 Feb 2013 22:48:13 +0100
Subject: [PATCH] daemon: Add `--listen'.

* nix/nix-daemon/guix-daemon.cc (GUIX_OPT_LISTEN): New macro.
  (options): Add `--listen'.
  (parse_opt): Handle it.
* doc/guix.texi (Invoking guix-daemon): Mention it.
---
 doc/guix.texi                 |  7 +++++++
 nix/nix-daemon/guix-daemon.cc | 19 ++++++++++++++++++-
 2 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/doc/guix.texi b/doc/guix.texi
index f84b37686a..849ab06c4a 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -367,6 +367,13 @@ Do not keep build logs.  By default they are kept under
 Assume @var{system} as the current system type.  By default it is the
 architecture/kernel pair found at configure time, such as
 @code{x86_64-linux}.
+
+@item --listen=@var{socket}
+Listen for connections on @var{socket}, the file name of a Unix-domain
+socket.  The default socket is
+@file{@var{localstatedir}/daemon-socket/socket}.  This option is only
+useful in exceptional circumstances, such as if you need to run several
+daemons on the same machine.
 @end table
 
 
diff --git a/nix/nix-daemon/guix-daemon.cc b/nix/nix-daemon/guix-daemon.cc
index 604a26f0b1..1611840bd4 100644
--- a/nix/nix-daemon/guix-daemon.cc
+++ b/nix/nix-daemon/guix-daemon.cc
@@ -1,5 +1,5 @@
 /* GNU Guix --- Functional package management for GNU
-   Copyright (C) 2012  Ludovic Courtès <ludo@gnu.org>
+   Copyright (C) 2012, 2013 Ludovic Courtès <ludo@gnu.org>
 
    This file is part of GNU Guix.
 
@@ -64,6 +64,7 @@ builds derivations on behalf of its clients.";
 #define GUIX_OPT_IMPERSONATE_LINUX_26 8
 #define GUIX_OPT_DEBUG 9
 #define GUIX_OPT_CHROOT_DIR 10
+#define GUIX_OPT_LISTEN 11
 
 static const struct argp_option options[] =
   {
@@ -103,6 +104,8 @@ static const struct argp_option options[] =
       " (this option has no effect in this configuration)"
 #endif
     },
+    { "listen", GUIX_OPT_LISTEN, "SOCKET", 0,
+      "Listen for connections on SOCKET" },
     { "debug", GUIX_OPT_DEBUG, 0, 0,
       "Produce debugging output" },
     { 0, 0, 0, 0, 0 }
@@ -138,6 +141,17 @@ parse_opt (int key, char *arg, struct argp_state *state)
     case GUIX_OPT_LOSE_LOGS:
       settings.keepLog = false;
       break;
+    case GUIX_OPT_LISTEN:
+      try
+	{
+	  settings.nixDaemonSocketFile = canonPath (arg);
+	}
+      catch (std::exception &e)
+	{
+	  fprintf (stderr, "error: %s\n", e.what ());
+	  exit (EXIT_FAILURE);
+	}
+      break;
     case GUIX_OPT_DEBUG:
       verbosity = lvlDebug;
       break;
@@ -207,6 +221,9 @@ main (int argc, char *argv[])
 	}
 #endif
 
+      printMsg (lvlDebug,
+		format ("listening on `%1%'") % settings.nixDaemonSocketFile);
+
       run (nothing);
     }
   catch (std::exception &e)