check if dhcpd exists and is executable

2 files changed, 10 insertions, 1 deletions

diff --git a/config.def.h b/config.def.h
index 8f6e7ec..2e822fd 100644
--- a/config.def.h
+++ b/config.def.h
@@ -15,6 +15,9 @@
 #define CONFIG_TEMPLATE	"/etc/dyndhcpd/dhcpd.conf"
 #define CONFIG_OUTPUT	"/run/dhcpd-%s.conf"
 
+/* dhcpd executable */
+#define DHCPDFILE	"/usr/bin/dhcpd"
+
 /* pathes for pid and leases file, these are passed to dhcpd */
 #define PIDFILE		"/run/dhcpd-%s.pid"
 #define LEASESFILE	"/var/lib/dhcp/dhcp-%s.leases"
diff --git a/dyndhcpd.c b/dyndhcpd.c
index 993b3ed..dde769b 100644
--- a/dyndhcpd.c
+++ b/dyndhcpd.c
@@ -108,6 +108,12 @@ int main(int argc, char ** argv) {
 		goto out;
 	}
 
+	/* check if dhcpd exists and is executable */
+	if (access(DHCPDFILE, X_OK) == -1) {
+		fprintf(stderr, "The dhcp daemon is not execatable!\n");
+		goto out;
+	}
+
 	/* get the domainname */
 	gethostname(hostname, 254);
 	hp = gethostbyname(hostname);
@@ -268,7 +274,7 @@ int main(int argc, char ** argv) {
 			if (verbose > 1)
 				printf("Running: dhcpd -f -d -q -4 -pf %s -lf %s -cf %s %s\n",
 					pidfile, leasesfile, filename, interface);
-			execlp("/usr/bin/dhcpd", "dhcpd", "-f", "-d", "-q", "-4",
+			execlp(DHCPDFILE, "dhcpd", "-f", "-d", "-q", "-4",
 				"-pf", pidfile, "-lf", leasesfile, "-cf", filename, interface, NULL);
 
 			rc = EXIT_SUCCESS;