add new hal-lock(1) utility

Before anyone starts complaining about 0.5.9 freeze, it's OK to add
this for 0.5.9 as such a utility is key to making legacy apps work
well. It also helped me uncover bugs in the libhal API and locking
logic.

2 files changed, 237 insertions, 1 deletions

diff --git a/tools/Makefile.am b/tools/Makefile.am
index 3c5a3026..0f73f61c 100644
--- a/tools/Makefile.am
+++ b/tools/Makefile.am
@@ -30,7 +30,8 @@ bin_PROGRAMS =                    \
 	hal-find-by-capability    \
 	hal-find-by-property      \
 	hal-device		  \
-	hal-is-caller-locked-out
+	hal-is-caller-locked-out  \
+	hal-lock
 
 lshal_SOURCES = lshal.c
 lshal_LDADD = @GLIB_LIBS@ $(top_builddir)/libhal/libhal.la
@@ -53,6 +54,9 @@ hal_device_LDADD = @DBUS_LIBS@ $(top_builddir)/libhal/libhal.la
 hal_is_caller_locked_out_SOURCES = hal-is-caller-locked-out.c
 hal_is_caller_locked_out_LDADD = @DBUS_LIBS@ $(top_builddir)/libhal/libhal.la
 
+hal_lock_SOURCES = hal-lock.c
+hal_lock_LDADD = @GLIB_LIBS@ @DBUS_LIBS@ $(top_builddir)/libhal/libhal.la
+
 libexec_PROGRAMS =                          \
 	hal-storage-mount	            \
 	hal-storage-unmount 	            \
diff --git a/tools/hal-lock.c b/tools/hal-lock.c
new file mode 100644
index 00000000..cd54f26d
--- /dev/null
+++ b/tools/hal-lock.c
@@ -0,0 +1,232 @@
+/***************************************************************************
+ * CVSID: $Id$
+ *
+ * hal-lock.c : Lock an interface
+ *
+ * Copyright (C) 2007 David Zeuthen, <david@fubar.dk>
+ *
+ * Licensed under the Academic Free License version 2.1
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ **************************************************************************/
+
+
+#ifdef HAVE_CONFIG_H
+#  include <config.h>
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <getopt.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <signal.h>
+#include <glib.h>
+
+#include "libhal.h"
+
+/** 
+ *  usage:
+ *  @argc:                Number of arguments given to program
+ *  @argv:                Arguments given to program
+ *
+ *  Print out program usage. 
+ */
+static void
+usage (int argc, char *argv[])
+{
+	fprintf (stderr,
+                 "\n"
+                 "usage : hal-lock --interface <interface>\n"
+                 "                 --run <program-and-args>\n"
+                 "                 [--udi <udi>]\n"
+                 "                 [--exclusive]\n"
+                 "                 [--help] [--version]\n");
+	fprintf (stderr,
+                 "\n"
+                 "        --interface      Interface to lock\n"
+                 "        --run            Program to run if the lock was acquired\n"
+                 "        --udi            Unique Device Id of device to lock. If\n"
+                 "                         ommitted the global lock will be tried\n"
+                 "        --exclusive      Whether the lock can be held by others\n"
+                 "        --version        Show version and exit\n"
+                 "        --help           Show this information and exit\n"
+                 "\n"
+                 "This program will attempt to grab a lock on a given interface.\n"
+                 "Unless, a specific UDI is given, the global lock will be tried.\n"
+                 "If the lock was succesfully acquired the program specified by\n"
+                 "the option --run will be run and upon termination this program\n"
+                 "will exit with exit code 0. If the lock wasn't acquired or an\n"
+                 "error occured while taking the lock, this program will exit with a\n"
+                 "non-zero exit code and the given program will not be run.\n"
+                 "\n");
+}
+
+/** 
+ *  main:
+ *  @argc:                Number of arguments given to program
+ *  @argv:                Arguments given to program
+ *
+ *  Returns:              Return code
+ *
+ *  Main entry point 
+ */
+int
+main (int argc, char *argv[])
+{
+	char *udi = NULL;
+	char *interface = NULL;
+        char *run = NULL;
+        dbus_bool_t is_version = FALSE;
+        dbus_bool_t exclusive = FALSE;
+        dbus_bool_t got_lock = FALSE;
+	DBusError error;
+        LibHalContext *hal_ctx;
+        int ret;
+        GError *g_error = NULL;
+
+        ret = 1;
+
+	if (argc <= 1) {
+		usage (argc, argv);
+                goto out;
+	}
+
+	while (1) {
+		int c;
+		int option_index = 0;
+		const char *opt;
+		static struct option long_options[] = {
+			{"udi", 1, NULL, 0},
+			{"interface", 1, NULL, 0},
+			{"run", 1, NULL, 0},
+			{"exclusive", 0, NULL, 0},
+			{"version", 0, NULL, 0},
+			{"help", 0, NULL, 0},
+			{NULL, 0, NULL, 0}
+		};
+
+		c = getopt_long (argc, argv, "",
+				 long_options, &option_index);
+		if (c == -1)
+			break;
+
+		switch (c) {
+		case 0:
+			opt = long_options[option_index].name;
+
+			if (strcmp (opt, "help") == 0) {
+				usage (argc, argv);
+				return 0;
+			} else if (strcmp (opt, "version") == 0) {
+				is_version = TRUE;
+			} else if (strcmp (opt, "udi") == 0) {
+				udi = strdup (optarg);
+			} else if (strcmp (opt, "run") == 0) {
+				run = strdup (optarg);
+			} else if (strcmp (opt, "exclusive") == 0) {
+                                exclusive = TRUE;
+			} else if (strcmp (opt, "interface") == 0) {
+				interface = strdup (optarg);
+			}
+			break;
+
+		default:
+			usage (argc, argv);
+			return 1;
+			break;
+		}
+	}
+
+	if (is_version) {
+		printf ("hal-lock " PACKAGE_VERSION "\n");
+                ret = 0;
+                goto out;
+	}
+
+	if (interface == NULL || run == NULL) {
+		usage (argc, argv);
+                goto out;
+	}
+
+
+        dbus_error_init (&error);	
+        if ((hal_ctx = libhal_ctx_new ()) == NULL) {
+                fprintf (stderr, "error: libhal_ctx_new\n");
+                goto out;
+        }
+        if (!libhal_ctx_set_dbus_connection (hal_ctx, dbus_bus_get (DBUS_BUS_SYSTEM, &error))) {
+                fprintf (stderr, "error: libhal_ctx_set_dbus_connection: %s: %s\n", error.name, error.message);
+                LIBHAL_FREE_DBUS_ERROR (&error);
+                goto out;
+        }
+        if (!libhal_ctx_init (hal_ctx, &error)) {
+                if (dbus_error_is_set(&error)) {
+                        fprintf (stderr, "error: libhal_ctx_init: %s: %s\n", error.name, error.message);
+                        dbus_error_free (&error);
+                }
+                fprintf (stderr, "Could not initialise connection to hald.\n"
+                         "Normally this means the HAL daemon (hald) is not running or not ready.\n");
+                goto out;
+        }
+        
+        if (udi != NULL) {
+                got_lock = libhal_device_acquire_interface_lock (hal_ctx,
+                                                                 udi,
+                                                                 interface,
+                                                                 exclusive,
+                                                                 &error);
+        } else {
+                got_lock = libhal_acquire_global_interface_lock (hal_ctx,
+                                                                 interface,
+                                                                 exclusive,
+                                                                 &error);
+        }
+                
+        if (dbus_error_is_set(&error)) {
+                fprintf (stderr, 
+                         "error: %s: %s: %s\n", 
+                         udi != NULL ? "libhal_device_acquire_interface_lock" : 
+                         "libhal_acquire_global_interface_lock",
+                         error.name, 
+                         error.message);
+                dbus_error_free (&error);
+                goto out;
+        }
+        
+        if (!got_lock) {
+                goto out;
+        }
+
+        /* now run the program while holding the lock */
+        if (!g_spawn_command_line_sync (run,
+                                        NULL,
+                                        NULL,
+                                        NULL,
+                                        &g_error)) {
+                
+                fprintf (stderr, "error: g_spawn_command_line_sync: %s\n", g_error->message);
+                g_error_free (g_error);
+                goto out;
+        }
+
+        ret = 0;
+
+out:
+        return ret;
+}