core: consolidate helper progam searching (bgo #734131)

Instead of having basically the same code in a bunch of different
place to find helper programs, just have one place do it.  Yes, this
does mean that the same sequence of paths is searched for all helpers
(so for example, dnsmasq will no longer be found first in /usr/local)
but I think consistency is the better option here.

https://bugzilla.gnome.org/show_bug.cgi?id=734131

15 files changed, 140 insertions, 240 deletions

diff --git a/configure.ac b/configure.ac
index 23898c3bbb..4add1fd65e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -643,10 +643,16 @@ if test "$with_dhclient" = "no" -a "$with_dhcpcd" = "no"; then
 fi
 # Add substitutions
 if test "$with_dhclient" != "no"; then
+	AC_DEFINE(WITH_DHCLIENT, TRUE, [Define if you have dhclient])
 	AC_SUBST(DHCLIENT_PATH, $with_dhclient)
+else
+	AC_DEFINE(WITH_DHCLIENT, FALSE, [Define if you have dhclient])
 fi
 if test "$with_dhcpcd" != "no"; then
+	AC_DEFINE(WITH_DHCPCD, TRUE, [Define if you have dhcpcd])
 	AC_SUBST(DHCPCD_PATH, $with_dhcpcd)
+else
+	AC_DEFINE(WITH_DHCPCD, FALSE, [Define if you have dhcpcd])
 fi
 
 # resolvconf and netconfig support
diff --git a/src/Makefile.am b/src/Makefile.am
index 1d9ba94435..ae4f26768e 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -40,6 +40,7 @@ AM_CPPFLAGS =				\
 	-I$(top_srcdir)/libnm-core	\
 	-I$(top_builddir)/libnm-core	\
 	-I$(top_srcdir)/callouts	\
+	-DPREFIX=\"$(prefix)\"          \
 	-DG_LOG_DOMAIN=\""NetworkManager"\" \
 	-DNETWORKMANAGER_COMPILATION	\
 	-DNM_VERSION_MAX_ALLOWED=NM_VERSION_NEXT_STABLE
diff --git a/src/NetworkManagerUtils.c b/src/NetworkManagerUtils.c
index 525154009e..b665984fe0 100644
--- a/src/NetworkManagerUtils.c
+++ b/src/NetworkManagerUtils.c
@@ -589,6 +589,56 @@ out:
 #undef LOG_NAME_FMT
 #undef LOG_NAME_ARGS
 
+/**
+ * nm_utils_find_helper:
+ * @progname: the helper program name, like "iptables"
+ * @try_first: a custom path to try first before searching
+ * @error: on failure, a "not found" error using @error_domain and @error_code
+ *
+ * Searches for the @progname in common system paths.
+ *
+ * Returns: the full path to the helper, if found, or %NULL if not found.
+ */
+const char *
+nm_utils_find_helper (const char *progname,
+                      const char *try_first,
+                      GError **error)
+{
+	static const char *paths[] = {
+		PREFIX "/sbin/",
+		PREFIX "/bin/",
+		"/sbin/",
+		"/usr/sbin/",
+		"/usr/local/sbin/",
+		"/usr/bin/",
+		"/usr/local/bin/",
+	};
+	guint i;
+	GString *tmp;
+	const char *ret;
+
+	if (error)
+		g_return_val_if_fail (*error == NULL, NULL);
+
+	if (try_first && try_first[0] && g_file_test (try_first, G_FILE_TEST_EXISTS))
+		return g_intern_string (try_first);
+
+	tmp = g_string_sized_new (50);
+	for (i = 0; i < G_N_ELEMENTS (paths); i++) {
+		g_string_append_printf (tmp, "%s%s", paths[i], progname);
+		if (g_file_test (tmp->str, G_FILE_TEST_EXISTS)) {
+			ret = g_intern_string (tmp->str);
+			g_string_free (tmp, TRUE);
+			return ret;
+		}
+		g_string_set_size (tmp, 0);
+	}
+	g_string_free (tmp, TRUE);
+
+	g_set_error (error, G_IO_ERROR, G_IO_ERROR_NOT_FOUND, "Could not find %s binary", progname);
+	return NULL;
+}
+
 /******************************************************************************************/
 
 gboolean
diff --git a/src/NetworkManagerUtils.h b/src/NetworkManagerUtils.h
index c1c65faa06..9a31053326 100644
--- a/src/NetworkManagerUtils.h
+++ b/src/NetworkManagerUtils.h
@@ -62,6 +62,10 @@ gboolean nm_utils_kill_child_sync (pid_t pid, int sig, guint64 log_domain, const
                                    int *child_status, guint32 wait_before_kill_msec,
                                    guint32 sleep_duration_msec);
 
+const char *nm_utils_find_helper (const char *progname,
+                                  const char *try_first,
+                                  GError **error);
+
 gboolean nm_match_spec_string (const GSList *specs, const char *string);
 gboolean nm_match_spec_hwaddr (const GSList *specs, const char *hwaddr);
 gboolean nm_match_spec_s390_subchannels (const GSList *specs, const char *subchannels);
diff --git a/src/devices/nm-device.c b/src/devices/nm-device.c
index 18b0ad21c7..a519a6808d 100644
--- a/src/devices/nm-device.c
+++ b/src/devices/nm-device.c
@@ -2508,27 +2508,17 @@ static NMActStageReturn
 aipd_start (NMDevice *self, NMDeviceStateReason *reason)
 {
 	NMDevicePrivate *priv = NM_DEVICE_GET_PRIVATE (self);
-	char *argv[6], *cmdline;
-	const char **aipd_binary = NULL;
-	static const char *aipd_paths[] = {
-		"/usr/sbin/avahi-autoipd",
-		"/usr/local/sbin/avahi-autoipd",
-		NULL
-	};
+	const char *argv[6];
+	char *cmdline;
+	const char *aipd_binary;
 	int i = 0;
 	GError *error = NULL;
 
 	aipd_cleanup (self);
 
 	/* Find avahi-autoipd */
-	aipd_binary = aipd_paths;
-	while (*aipd_binary != NULL) {
-		if (g_file_test (*aipd_binary, G_FILE_TEST_EXISTS))
-			break;
-		aipd_binary++;
-	}
-
-	if (!*aipd_binary) {
+	aipd_binary = nm_utils_find_helper ("avahi-autoipd", NULL, NULL);
+	if (!aipd_binary) {
 		_LOGW (LOGD_DEVICE | LOGD_AUTOIP4,
 		       "Activation: Stage 3 of 5 (IP Configure Start) failed"
 		       " to start avahi-autoipd: not found");
@@ -2536,20 +2526,20 @@ aipd_start (NMDevice *self, NMDeviceStateReason *reason)
 		return NM_ACT_STAGE_RETURN_FAILURE;
 	}
 
-	argv[i++] = (char *) (*aipd_binary);
+	argv[i++] = aipd_binary;
 	argv[i++] = "--script";
-	argv[i++] = (char *) nm_device_autoipd_helper_path;
+	argv[i++] = nm_device_autoipd_helper_path;
 
 	if (nm_logging_enabled (LOGL_DEBUG, LOGD_AUTOIP4))
 		argv[i++] = "--debug";
-	argv[i++] = (char *) nm_device_get_ip_iface (self);
+	argv[i++] = nm_device_get_ip_iface (self);
 	argv[i++] = NULL;
 
-	cmdline = g_strjoinv (" ", argv);
+	cmdline = g_strjoinv (" ", (char **) argv);
 	_LOGD (LOGD_AUTOIP4, "running: %s", cmdline);
 	g_free (cmdline);
 
-	if (!g_spawn_async ("/", argv, NULL, G_SPAWN_DO_NOT_REAP_CHILD,
+	if (!g_spawn_async ("/", (char **) argv, NULL, G_SPAWN_DO_NOT_REAP_CHILD,
 	                    &aipd_child_setup, NULL, &(priv->aipd_pid), &error)) {
 		_LOGW (LOGD_DEVICE | LOGD_AUTOIP4,
 		       "Activation: Stage 3 of 5 (IP Configure Start) failed"
diff --git a/src/devices/team/nm-device-team.c b/src/devices/team/nm-device-team.c
index b524ba7efd..40055961bd 100644
--- a/src/devices/team/nm-device-team.c
+++ b/src/devices/team/nm-device-team.c
@@ -422,12 +422,7 @@ teamd_start (NMDevice *device, NMSettingTeam *s_team)
 	const char *iface = nm_device_get_ip_iface (device);
 	char *tmp_str = NULL;
 	const char *config;
-	const char **teamd_binary = NULL;
-	static const char *teamd_paths[] = {
-		"/usr/bin/teamd",
-		"/usr/local/bin/teamd",
-		NULL
-	};
+	const char *teamd_binary;
 	GPtrArray *argv;
 	GError *error = NULL;
 	gboolean ret;
@@ -443,21 +438,15 @@ teamd_start (NMDevice *device, NMSettingTeam *s_team)
 		return TRUE;
 	}
 
-	teamd_binary = teamd_paths;
-	while (*teamd_binary != NULL) {
-		if (g_file_test (*teamd_binary, G_FILE_TEST_EXISTS))
-			break;
-		teamd_binary++;
-	}
-
-	if (!*teamd_binary) {
+	teamd_binary = nm_utils_find_helper ("teamd", NULL, NULL);
+	if (!teamd_binary) {
 		_LOGW (LOGD_TEAM, "Activation: (team) failed to start teamd: teamd binary not found");
 		return FALSE;
 	}
 
 	/* Kill teamd for same named device first if it is there */
 	argv = g_ptr_array_new ();
-	g_ptr_array_add (argv, (gpointer) *teamd_binary);
+	g_ptr_array_add (argv, (gpointer) teamd_binary);
 	g_ptr_array_add (argv, (gpointer) "-k");
 	g_ptr_array_add (argv, (gpointer) "-t");
 	g_ptr_array_add (argv, (gpointer) iface);
@@ -472,7 +461,7 @@ teamd_start (NMDevice *device, NMSettingTeam *s_team)
 
 	/* Start teamd now */
 	argv = g_ptr_array_new ();
-	g_ptr_array_add (argv, (gpointer) *teamd_binary);
+	g_ptr_array_add (argv, (gpointer) teamd_binary);
 	g_ptr_array_add (argv, (gpointer) "-o");
 	g_ptr_array_add (argv, (gpointer) "-n");
 	g_ptr_array_add (argv, (gpointer) "-U");
diff --git a/src/dhcp-manager/nm-dhcp-dhclient.c b/src/dhcp-manager/nm-dhcp-dhclient.c
index d5ea6a5486..74b416a7bb 100644
--- a/src/dhcp-manager/nm-dhcp-dhclient.c
+++ b/src/dhcp-manager/nm-dhcp-dhclient.c
@@ -42,13 +42,13 @@
 #include "nm-dhcp-dhclient-utils.h"
 #include "nm-dhcp-manager.h"
 #include "nm-posix-signals.h"
+#include "NetworkManagerUtils.h"
 
 G_DEFINE_TYPE (NMDhcpDhclient, nm_dhcp_dhclient, NM_TYPE_DHCP_CLIENT)
 
 #define NM_DHCP_DHCLIENT_GET_PRIVATE(o) (G_TYPE_INSTANCE_GET_PRIVATE ((o), NM_TYPE_DHCP_DHCLIENT, NMDhcpDhclientPrivate))
 
 typedef struct {
-	const char *path;
 	char *conf_file;
 	const char *def_leasefile;
 	char *lease_file;
@@ -56,27 +56,13 @@ typedef struct {
 } NMDhcpDhclientPrivate;
 
 const char *
-nm_dhcp_dhclient_get_path (const char *try_first)
+nm_dhcp_dhclient_get_path (void)
 {
-	static const char *dhclient_paths[] = {
-		"/sbin/dhclient",
-		"/usr/sbin/dhclient",
-		"/usr/pkg/sbin/dhclient",
-		"/usr/local/sbin/dhclient",
-		NULL
-	};
-	const char **path = dhclient_paths;
-
-	if (strlen (try_first) && g_file_test (try_first, G_FILE_TEST_EXISTS))
-		return try_first;
-
-	while (*path != NULL) {
-		if (g_file_test (*path, G_FILE_TEST_EXISTS))
-			break;
-		path++;
-	}
+	const char *path = NULL;
 
-	return *path;
+	if (WITH_DHCLIENT)
+		path = nm_utils_find_helper ("dhclient", DHCLIENT_PATH, NULL);
+	return path;
 }
 
 /**
@@ -335,7 +321,7 @@ dhclient_start (NMDhcpClient *client,
 	GPtrArray *argv = NULL;
 	pid_t pid;
 	GError *error = NULL;
-	const char *iface, *uuid, *system_bus_address;
+	const char *iface, *uuid, *system_bus_address, *dhclient_path = NULL;
 	char *binary_name, *cmd_str, *pid_file = NULL, *system_bus_address_env = NULL;
 	gboolean ipv6, success;
 	guint log_domain;
@@ -349,8 +335,9 @@ dhclient_start (NMDhcpClient *client,
 
 	log_domain = ipv6 ? LOGD_DHCP6 : LOGD_DHCP4;
 
-	if (!g_file_test (priv->path, G_FILE_TEST_EXISTS)) {
-		nm_log_warn (log_domain, "%s does not exist.", priv->path);
+	dhclient_path = nm_dhcp_dhclient_get_path ();
+	if (!dhclient_path) {
+		nm_log_warn (log_domain, "dhclient could not be found");
 		return FALSE;
 	}
 
@@ -359,7 +346,7 @@ dhclient_start (NMDhcpClient *client,
 		                        iface);
 
 	/* Kill any existing dhclient from the pidfile */
-	binary_name = g_path_get_basename (priv->path);
+	binary_name = g_path_get_basename (dhclient_path);
 	nm_dhcp_client_stop_existing (pid_file, binary_name);
 	g_free (binary_name);
 
@@ -411,7 +398,7 @@ dhclient_start (NMDhcpClient *client,
 	}
 
 	argv = g_ptr_array_new ();
-	g_ptr_array_add (argv, (gpointer) priv->path);
+	g_ptr_array_add (argv, (gpointer) dhclient_path);
 
 	g_ptr_array_add (argv, (gpointer) "-d");
 
@@ -608,8 +595,6 @@ nm_dhcp_dhclient_init (NMDhcpDhclient *self)
 	NMDhcpDhclientPrivate *priv = NM_DHCP_DHCLIENT_GET_PRIVATE (self);
 	const char **iter = &def_leasefiles[0];
 
-	priv->path = nm_dhcp_dhclient_get_path (DHCLIENT_PATH);
-
 	while (iter && *iter) {
 		if (g_file_test (*iter, G_FILE_TEST_EXISTS)) {
 			priv->def_leasefile = *iter;
diff --git a/src/dhcp-manager/nm-dhcp-dhclient.h b/src/dhcp-manager/nm-dhcp-dhclient.h
index 8192a599b1..6c58826241 100644
--- a/src/dhcp-manager/nm-dhcp-dhclient.h
+++ b/src/dhcp-manager/nm-dhcp-dhclient.h
@@ -45,7 +45,7 @@ GSList *nm_dhcp_dhclient_get_lease_ip_configs (const char *iface,
                                                const char *uuid,
                                                gboolean ipv6);
 
-const char *nm_dhcp_dhclient_get_path (const char *try_first);
+const char *nm_dhcp_dhclient_get_path (void);
 
 #endif /* __NETWORKMANAGER_DHCP_DHCLIENT_H__ */
 
diff --git a/src/dhcp-manager/nm-dhcp-dhcpcd.c b/src/dhcp-manager/nm-dhcp-dhcpcd.c
index 8345034b84..98b54b10f4 100644
--- a/src/dhcp-manager/nm-dhcp-dhcpcd.c
+++ b/src/dhcp-manager/nm-dhcp-dhcpcd.c
@@ -37,38 +37,24 @@
 #include "nm-utils.h"
 #include "nm-logging.h"
 #include "nm-posix-signals.h"
+#include "NetworkManagerUtils.h"
 
 G_DEFINE_TYPE (NMDhcpDhcpcd, nm_dhcp_dhcpcd, NM_TYPE_DHCP_CLIENT)
 
 #define NM_DHCP_DHCPCD_GET_PRIVATE(o) (G_TYPE_INSTANCE_GET_PRIVATE ((o), NM_TYPE_DHCP_DHCPCD, NMDhcpDhcpcdPrivate))
 
 typedef struct {
-	const char *path;
 	char *pid_file;
 } NMDhcpDhcpcdPrivate;
 
 const char *
-nm_dhcp_dhcpcd_get_path (const char *try_first)
+nm_dhcp_dhcpcd_get_path (void)
 {
-	static const char *dhcpcd_paths[] = {
-		"/sbin/dhcpcd",
-		"/usr/sbin/dhcpcd",
-		"/usr/pkg/sbin/dhcpcd",
-		"/usr/local/sbin/dhcpcd",
-		NULL
-	};
-	const char **path = dhcpcd_paths;
-
-	if (strlen (try_first) && g_file_test (try_first, G_FILE_TEST_EXISTS))
-		return try_first;
-
-	while (*path != NULL) {
-		if (g_file_test (*path, G_FILE_TEST_EXISTS))
-			break;
-		path++;
-	}
+	const char *path = NULL;
 
-	return *path;
+	if (WITH_DHCPCD)
+		path = nm_utils_find_helper ("dhcpcd", DHCPCD_PATH, NULL);
+	return path;
 }
 
 static void
@@ -96,7 +82,7 @@ ip4_start (NMDhcpClient *client,
 	pid_t pid = -1;
 	GError *error = NULL;
 	char *pid_contents = NULL, *binary_name, *cmd_str;
-	const char *iface;
+	const char *iface, *dhcpcd_path = NULL;
 
 	g_return_val_if_fail (priv->pid_file == NULL, FALSE);
 
@@ -107,18 +93,19 @@ ip4_start (NMDhcpClient *client,
 	 */
 	priv->pid_file = g_strdup_printf (RUNDIR "/dhcpcd-%s.pid", iface);
 
-	if (!g_file_test (priv->path, G_FILE_TEST_EXISTS)) {
-		nm_log_warn (LOGD_DHCP4, "%s does not exist.", priv->path);
+	dhcpcd_path = nm_dhcp_dhcpcd_get_path ();
+	if (!dhcpcd_path) {
+		nm_log_warn (LOGD_DHCP4, "dhcpcd could not be found");
 		return FALSE;
 	}
 
 	/* Kill any existing dhcpcd from the pidfile */
-	binary_name = g_path_get_basename (priv->path);
+	binary_name = g_path_get_basename (dhcpcd_path);
 	nm_dhcp_client_stop_existing (priv->pid_file, binary_name);
 	g_free (binary_name);
 
 	argv = g_ptr_array_new ();
-	g_ptr_array_add (argv, (gpointer) priv->path);
+	g_ptr_array_add (argv, (gpointer) dhcpcd_path);
 
 	g_ptr_array_add (argv, (gpointer) "-B");	/* Don't background on lease (disable fork()) */
 
@@ -202,9 +189,6 @@ stop (NMDhcpClient *client, gboolean release, const GByteArray *duid)
 static void
 nm_dhcp_dhcpcd_init (NMDhcpDhcpcd *self)
 {
-	NMDhcpDhcpcdPrivate *priv = NM_DHCP_DHCPCD_GET_PRIVATE (self);
-
-	priv->path = nm_dhcp_dhcpcd_get_path (DHCPCD_PATH);
 }
 
 static void
diff --git a/src/dhcp-manager/nm-dhcp-dhcpcd.h b/src/dhcp-manager/nm-dhcp-dhcpcd.h
index 6dfe0dda97..4e3502ab5a 100644
--- a/src/dhcp-manager/nm-dhcp-dhcpcd.h
+++ b/src/dhcp-manager/nm-dhcp-dhcpcd.h
@@ -41,7 +41,7 @@ typedef struct {
 
 GType nm_dhcp_dhcpcd_get_type (void);
 
-const char *nm_dhcp_dhcpcd_get_path (const char *try_first);
+const char *nm_dhcp_dhcpcd_get_path (void);
 
 #endif /* __NETWORKMANAGER_DHCP_DHCPCD_H__ */
 
diff --git a/src/dhcp-manager/nm-dhcp-manager.c b/src/dhcp-manager/nm-dhcp-manager.c
index a1bbbef50f..f24aad8dcc 100644
--- a/src/dhcp-manager/nm-dhcp-manager.c
+++ b/src/dhcp-manager/nm-dhcp-manager.c
@@ -285,23 +285,16 @@ dis_connection_cb (NMDBusManager *mgr,
 static GType
 get_client_type (const char *client, GError **error)
 {
-	const char *dhclient_path = NULL;
-	const char *dhcpcd_path = NULL;
+	gboolean use_dhclient, use_dhcpcd;
 
-	/* If a client was disabled at build-time, its *_PATH define will be
-	 * an empty string.
-	 */
-	/* coverity[array_null] */
-	if (DHCLIENT_PATH && strlen (DHCLIENT_PATH))
-		dhclient_path = nm_dhcp_dhclient_get_path (DHCLIENT_PATH);
-	/* coverity[array_null] */
-	if (DHCPCD_PATH && strlen (DHCPCD_PATH))
-		dhcpcd_path = nm_dhcp_dhcpcd_get_path (DHCPCD_PATH);
+	/* If a client was disabled at build-time, these will return FALSE */
+	use_dhclient = !!nm_dhcp_dhclient_get_path ();
+	use_dhcpcd = !!nm_dhcp_dhcpcd_get_path ();
 
 	if (!client) {
-		if (dhclient_path)
+		if (use_dhclient)
 			return NM_TYPE_DHCP_DHCLIENT;
-		else if (dhcpcd_path)
+		else if (use_dhcpcd)
 			return NM_TYPE_DHCP_DHCPCD;
 		else {
 			g_set_error_literal (error,
@@ -312,20 +305,20 @@ get_client_type (const char *client, GError **error)
 	}
 
 	if (!strcmp (client, "dhclient")) {
-		if (!dhclient_path) {
+		if (!use_dhclient) {
 			g_set_error_literal (error,
 			                     NM_DHCP_MANAGER_ERROR, NM_DHCP_MANAGER_ERROR_BAD_CLIENT,
-			                     _("'dhclient' could be found."));
+			                     _("'dhclient' could not be found or was disabled."));
 			return G_TYPE_INVALID;
 		}
 		return NM_TYPE_DHCP_DHCLIENT;
 	}
 
 	if (!strcmp (client, "dhcpcd")) {
-		if (!dhcpcd_path) {
+		if (!use_dhcpcd) {
 			g_set_error_literal (error,
 			                     NM_DHCP_MANAGER_ERROR, NM_DHCP_MANAGER_ERROR_BAD_CLIENT,
-			                     _("'dhcpcd' could be found."));
+			                     _("'dhcpcd' could not be found or was disabled."));
 			return G_TYPE_INVALID;
 		}
 		return NM_TYPE_DHCP_DHCPCD;
diff --git a/src/dns-manager/nm-dns-dnsmasq.c b/src/dns-manager/nm-dns-dnsmasq.c
index 8367693da7..416cfe3b01 100644
--- a/src/dns-manager/nm-dns-dnsmasq.c
+++ b/src/dns-manager/nm-dns-dnsmasq.c
@@ -35,6 +35,7 @@
 #include "nm-ip4-config.h"
 #include "nm-ip6-config.h"
 #include "nm-dns-utils.h"
+#include "NetworkManagerUtils.h"
 
 G_DEFINE_TYPE (NMDnsDnsmasq, nm_dns_dnsmasq, NM_TYPE_DNS_PLUGIN)
 
@@ -50,26 +51,6 @@ typedef struct {
 
 /*******************************************/
 
-static inline const char *
-find_dnsmasq (void)
-{
-	static const char *paths[] = {
-		DNSMASQ_PATH,
-		"/usr/local/sbin/dnsmasq",
-		"/usr/sbin/dnsmasq",
-		"/sbin/dnsmasq",
-		NULL
-	};
-	const char **binary = paths;
-
-	while (*binary != NULL) {
-		if (**binary && g_file_test (*binary, G_FILE_TEST_EXISTS))
-			return *binary;
-		binary++;
-	}
-	return NULL;
-}
-
 static gboolean
 add_ip4_config (GString *str, NMIP4Config *ip4, gboolean split)
 {
@@ -225,6 +206,7 @@ update (NMDnsPlugin *plugin,
         const char *hostname)
 {
 	NMDnsDnsmasq *self = NM_DNS_DNSMASQ (plugin);
+	const char *dm_binary;
 	GString *conf;
 	GSList *iter;
 	const char *argv[15];
@@ -240,6 +222,12 @@ update (NMDnsPlugin *plugin,
 	 */
 	nm_dns_plugin_child_kill (plugin);
 
+	dm_binary = nm_utils_find_helper ("dnsmasq", DNSMASQ_PATH, NULL);
+	if (!dm_binary) {
+		nm_log_warn (LOGD_DNS, "Could not find dnsmasq binary");
+		return FALSE;
+	}
+
 	/* Build up the new dnsmasq config file */
 	conf = g_string_sized_new (150);
 
@@ -281,7 +269,7 @@ update (NMDnsPlugin *plugin,
 	nm_log_dbg (LOGD_DNS, "dnsmasq local caching DNS configuration:");
 	nm_log_dbg (LOGD_DNS, "%s", conf->str);
 
-	argv[idx++] = find_dnsmasq ();
+	argv[idx++] = dm_binary;
 	argv[idx++] = "--no-resolv";  /* Use only commandline */
 	argv[idx++] = "--keep-in-foreground";
 	argv[idx++] = "--no-hosts"; /* don't use /etc/hosts to resolve */
diff --git a/src/dnsmasq-manager/nm-dnsmasq-manager.c b/src/dnsmasq-manager/nm-dnsmasq-manager.c
index c76b5fe5c5..7d6337e914 100644
--- a/src/dnsmasq-manager/nm-dnsmasq-manager.c
+++ b/src/dnsmasq-manager/nm-dnsmasq-manager.c
@@ -169,27 +169,6 @@ nm_cmd_line_add_string (NMCmdLine *cmd, const char *str)
 
 /*******************************************/
 
-static inline const char *
-nm_find_dnsmasq (void)
-{
-	static const char *dnsmasq_binary_paths[] = {
-		DNSMASQ_PATH,
-		"/usr/local/sbin/dnsmasq",
-		"/usr/sbin/dnsmasq",
-		"/sbin/dnsmasq",
-		NULL
-	};
-	const char **dnsmasq_binary = dnsmasq_binary_paths;
-
-	while (*dnsmasq_binary != NULL) {
-		if (**dnsmasq_binary && g_file_test (*dnsmasq_binary, G_FILE_TEST_EXISTS))
-			break;
-		dnsmasq_binary++;
-	}
-
-	return *dnsmasq_binary;
-}
-
 static void
 dm_exit_code (guint dm_exit_status)
 {
@@ -250,7 +229,6 @@ create_dm_cmd_line (const char *iface,
                     const char *pidfile,
                     GError **error)
 {
-	const char *dm_binary;
 	NMCmdLine *cmd;
 	GString *s;
 	const NMPlatformIP4Address *tmp;
@@ -258,16 +236,11 @@ create_dm_cmd_line (const char *iface,
 	char last[INET_ADDRSTRLEN];
 	char localaddr[INET_ADDRSTRLEN];
 	char *error_desc = NULL;
+	const char *dm_binary;
 
-	dm_binary = nm_find_dnsmasq ();
-	if (!dm_binary) {
-		g_set_error_literal (error, NM_DNSMASQ_MANAGER_ERROR, NM_DNSMASQ_MANAGER_ERROR_NOT_FOUND,
-		                     "Could not find dnsmasq binary.");
+	dm_binary = nm_utils_find_helper ("dnsmasq", DNSMASQ_PATH, error);
+	if (!dm_binary)
 		return NULL;
-	}
-
-	/* Find the IP4 address to use */
-	tmp = nm_ip4_config_get_address (ip4_config, 0);
 
 	/* Create dnsmasq command line */
 	cmd = nm_cmd_line_new ();
@@ -298,6 +271,9 @@ create_dm_cmd_line (const char *iface,
 	 */
 	nm_cmd_line_add_string (cmd, "--strict-order");
 
+	/* Find the IP4 address to use */
+	tmp = nm_ip4_config_get_address (ip4_config, 0);
+
 	s = g_string_new ("--listen-address=");
 	nm_utils_inet4_ntop (tmp->address, localaddr);
 	g_string_append (s, localaddr);
@@ -311,7 +287,8 @@ create_dm_cmd_line (const char *iface,
 		                     error_desc);
 		nm_log_warn (LOGD_SHARING, "Failed to find DHCP address ranges: %s", error_desc);
 		g_free (error_desc);
-		goto error;
+		nm_cmd_line_destroy (cmd);
+		return NULL;
 	}
 
 	s = g_string_new ("--dhcp-range=");
@@ -332,10 +309,6 @@ create_dm_cmd_line (const char *iface,
 	g_string_free (s, TRUE);
 
 	return cmd;
-
-error:
-	nm_cmd_line_destroy (cmd);
-	return NULL;
 }
 
 static void
diff --git a/src/nm-dcb.c b/src/nm-dcb.c
index 3bdbf7d5ed..3829e1a2e9 100644
--- a/src/nm-dcb.c
+++ b/src/nm-dcb.c
@@ -296,47 +296,20 @@ _fcoe_cleanup (const char *iface,
 	return do_helper (NULL, FCOEADM, run_func, user_data, error, "-d %s", iface);
 }
 
-
-static const char *dcbpaths[] = {
-	"/sbin/dcbtool",
-	"/usr/sbin/dcbtool",
-	"/usr/local/sbin/dcbtool",
-	NULL
-};
-static const char *fcoepaths[] = {
-	"/sbin/fcoeadm",
-	"/usr/sbin/fcoeadm",
-	"/usr/local/sbin/fcoeadm",
-	NULL
-};
-
-
 static gboolean
 run_helper (char **argv, guint which, gpointer user_data, GError **error)
 {
-	static const char *helper_path[2] = { NULL, NULL };
+	const char *helper_path;
 	int exit_status = 0;
 	gboolean success;
 	char *errmsg = NULL, *outmsg = NULL;
-	const char **iter;
 	char *cmdline;
 
-	if (G_UNLIKELY (helper_path[which] == NULL)) {
-		iter = (which == DCBTOOL) ? dcbpaths : fcoepaths;
-		while (*iter) {
-			if (g_file_test (*iter, G_FILE_TEST_EXISTS))
-				helper_path[which] = *iter;
-			iter++;
-		}
-		if (!helper_path[which]) {
-			g_set_error (error, NM_DCB_ERROR, NM_DCB_ERROR_HELPER_NOT_FOUND,
-			             "%s not found",
-			             which == DCBTOOL ? "dcbtool" : "fcoadm");
-			return FALSE;
-		}
-	}
+	helper_path = nm_utils_find_helper ((which == DCBTOOL) ? "dcbtool" : "fcoeadm", NULL, error);
+	if (!helper_path)
+		return FALSE;
 
-	argv[0] = (char *) helper_path[which];
+	argv[0] = (char *) helper_path;
 	cmdline = g_strjoinv (" ", argv);
 	nm_log_dbg (LOGD_DCB, "%s", cmdline);
 
@@ -359,9 +332,9 @@ run_helper (char **argv, guint which, gpointer user_data, GError **error)
 			success = FALSE;
 		}
 	}
+
 	g_free (outmsg);
 	g_free (errmsg);
-
 	g_free (cmdline);
 	return success;
 }
diff --git a/src/ppp-manager/nm-ppp-manager.c b/src/ppp-manager/nm-ppp-manager.c
index 2c9d1c3d04..0b8481d419 100644
--- a/src/ppp-manager/nm-ppp-manager.c
+++ b/src/ppp-manager/nm-ppp-manager.c
@@ -751,36 +751,6 @@ nm_cmd_line_add_int (NMCmdLine *cmd, int i)
 
 /*******************************************/
 
-static const char *pppd_binary_paths[] = {
-	PPPD_PATH,
-	"/usr/local/sbin/pppd",
-	"/usr/sbin/pppd",
-	"/sbin/pppd",
-	NULL
-};
-
-static const char *pppoe_binary_paths[] = {
-	PPPOE_PATH,
-	"/usr/local/sbin/pppoe",
-	"/usr/sbin/pppoe",
-	"/sbin/pppoe",
-	NULL
-};
-
-static inline const char *
-nm_find_binary (const char *paths[])
-{
-	const char **binary = paths;
-
-	while (*binary != NULL) {
-		if (**binary && g_file_test (*binary, G_FILE_TEST_EXISTS))
-			break;
-		binary++;
-	}
-
-	return *binary;
-}
-
 static void
 ppp_exit_code (guint pppd_exit_status, GPid pid)
 {
@@ -900,27 +870,21 @@ create_pppd_cmd_line (NMPPPManager *self,
                       GError **err)
 {
 	NMPPPManagerPrivate *priv = NM_PPP_MANAGER_GET_PRIVATE (self);
-	const char *pppd_binary, *pppoe_binary = NULL;
+	const char *pppd_binary = NULL, *pppoe_binary = NULL;
 	NMCmdLine *cmd;
 	gboolean ppp_debug;
 
 	g_return_val_if_fail (setting != NULL, NULL);
 
-	pppd_binary = nm_find_binary (pppd_binary_paths);
-	if (!pppd_binary) {
-		g_set_error (err, NM_PPP_MANAGER_ERROR, NM_PPP_MANAGER_ERROR,
-		             "Could not find pppd binary.");
+	pppd_binary = nm_utils_find_helper ("pppd", NULL, err);
+	if (!pppd_binary)
 		return NULL;
-	}
 
 	if (   pppoe
 	    || (adsl && strcmp (nm_setting_adsl_get_protocol (adsl), NM_SETTING_ADSL_PROTOCOL_PPPOE))) {
-		pppoe_binary = nm_find_binary (pppoe_binary_paths);
-		if (!pppoe_binary) {
-			g_set_error (err, NM_PPP_MANAGER_ERROR, NM_PPP_MANAGER_ERROR,
-			             "Could not find pppoe binary.");
+		pppoe_binary = nm_utils_find_helper ("pppoe", NULL, err);
+		if (!pppoe_binary)
 			return NULL;
-		}
 	}
 
 	/* Create pppd command line */