add open_read_close() and similar stuff

networking/udhcp/arpping.c

@@ -49,7 +49,7 @@ int arpping(uint32_t yiaddr, uint32_t ip, uint8_t *mac, char *interface)
 	}
 
 	if (setsockopt(s, SOL_SOCKET, SO_BROADCAST, &optval, sizeof(optval)) == -1) {
-		bb_perror_msg("Could not setsocketopt on raw socket");
+		bb_perror_msg("cannot setsocketopt on raw socket");
 		close(s);
 		return -1;
 	}

networking/udhcp/clientpacket.c

@@ -39,16 +39,13 @@ unsigned long random_xid(void)
 {
 	static int initialized;
 	if (!initialized) {
-		int fd;
 		unsigned long seed;
 
-		fd = open("/dev/urandom", 0);
-		if (fd < 0 || read(fd, &seed, sizeof(seed)) < 0) {
-			bb_info_msg("Could not load seed "
+		if (open_read_close("/dev/urandom", &seed, sizeof(seed)) < 0) {
+			bb_info_msg("Cannot load seed "
 				"from /dev/urandom: %s", strerror(errno));
 			seed = time(0);
 		}
-		if (fd >= 0) close(fd);
 		srand(seed);
 		initialized++;
 	}

networking/udhcp/options.c

@@ -171,6 +171,6 @@ int add_simple_option(uint8_t *optionptr, uint8_t code, uint32_t data)
 		}
 	}
 
-	bb_error_msg("Could not add option 0x%02x", code);
+	bb_error_msg("cannot add option 0x%02x", code);
 	return 0;
 }

networking/udhcp/signalpipe.c

@@ -36,7 +36,7 @@ static int signal_pipe[2];
 static void signal_handler(int sig)
 {
 	if (send(signal_pipe[1], &sig, sizeof(sig), MSG_DONTWAIT) < 0)
-		bb_perror_msg("Could not send signal");
+		bb_perror_msg("cannot send signal");
 }