cmd: let the helper print the Error prefix

The messages said Error: themselves, or usage:, or nothing at all.
cmd_error() prints the prefix now, so every rejected command answers the
same way and the strings only carry what is specific to them.

Two messages that started with Error or refusing are reworded so the
prefix does not read twice. The syslog usage text becomes one string
instead of three calls.

cmd_parser.c

@@ -426,19 +426,20 @@ err:
 	return 0;
 }
 
+static void cmd_error(__code const char *msg)
+{
+	err_status = ERR_INVALID_ARGUMENT;
+	print_string("Error: ");
+	print_string(msg);
+}
+
+
 // Sets the management MAC from a "mac <aa:bb:cc:dd:ee:ff>" command (or prints
 // the current one with a bare "mac"). Refuses blank/multicast/locally
 // administered/all-zero-OUI addresses so the running MAC stays reachable, and
 // re-registers the static L2 management entry so the change applies without a
 // reboot. As a regular command a "mac ..." line in the startup config applies
 // on every boot (execute_config runs before the final static L2 entry).
-static void cmd_error(__code const char *msg)
-{
-	err_status = ERR_INVALID_ARGUMENT;
-	print_string(msg);
-}
-
-
 void parse_mac_cmd(void)
 {
 	if (cmd_words_len == 1) {
@@ -448,11 +449,11 @@ void parse_mac_cmd(void)
 		return;
 	}
 	if (cmd_words_len != 2 || !parse_mac(cmd_words_b[1])) {
-		cmd_error("Error: mac [<aa:bb:cc:dd:ee:ff>]\n");
+		cmd_error("mac [<aa:bb:cc:dd:ee:ff>]\n");
 		return;
 	}
 	if ((mac_parse_result[0] & 0x03) || ((mac_parse_result[0] | mac_parse_result[1] | mac_parse_result[2]) == 0)) {
-		cmd_error("refusing: must be unicast, globally administered\n");
+		cmd_error("the MAC must be unicast and globally administered\n");
 		return;
 	}
 	if (memcmp(mac_parse_result, uip_ethaddr.addr, 6) == 0) {
@@ -530,7 +531,7 @@ void parse_lag(void)
 	port_lag_members_set(group, members);
 	return;
 err:
-	cmd_error("Error: lag (show | <1-4> (d | <port>...))\n");
+	cmd_error("lag (show | <1-4> (d | <port>...))\n");
 }
 
 
@@ -572,7 +573,7 @@ void parse_lag_hash(void)
 	port_lag_hash_set(group, hash);
 	return;
 err:
-	cmd_error("Error: laghash <1-4> [smac|dmac|sip|dip|sport|dport]\n");
+	cmd_error("laghash <1-4> [smac|dmac|sip|dip|sport|dport]\n");
 }
 
 
@@ -670,7 +671,7 @@ void parse_vlan(void)
 	}
 	return;
 err:
-	cmd_error("Error: vlan (<vlan-id>|show) [port][t]...\n");
+	cmd_error("vlan (<vlan-id>|show) [port][t]...\n");
 }
 
 
@@ -721,7 +722,7 @@ void parse_isolate(void)
 	return;
 
 err:
-	cmd_error("Error: isolate <port> [show|off] [port]...\n");
+	cmd_error("isolate <port> [show|off] [port]...\n");
 }
 
 
@@ -758,7 +759,7 @@ void parse_ingress(void)
 		// Setting mode for all ports at once
 		for (log_port = machine.min_port; log_port <= machine.max_port; log_port++) {
 			if (!port_ingress_filter(log_port, mode)) {
-				cmd_error("Error setting ingress filter for port "); print_phys_port(log_port); write_char('\n');
+				cmd_error("cannot set the ingress filter for port "); print_phys_port(log_port); write_char('\n');
 				return;
 			}
 			print_string("All ports ingress filter set to: ");
@@ -780,7 +781,7 @@ void parse_ingress(void)
 				goto err;
 			}
 			if (!port_ingress_filter(log_port, mode)) {
-				cmd_error("Error setting ingress filter for port "); print_phys_port(log_port); write_char('\n');
+				cmd_error("cannot set the ingress filter for port "); print_phys_port(log_port); write_char('\n');
 				return;
 			}
 			print_string("Port "); print_phys_port(log_port);
@@ -790,7 +791,7 @@ void parse_ingress(void)
 	}
 	return;
 err:
-	cmd_error("Error: ingress [p]<u/t/a>...\n");
+	cmd_error("ingress [p]<u/t/a>...\n");
 }
 
 void parse_mirror(void)
@@ -1105,7 +1106,7 @@ void parse_regget(void)
 	return;
 
 err:
-	cmd_error("usage: regget <hexvalue>\n\tlike: regget 0BB0 or regget 0c");
+	cmd_error("regget <hexvalue>\n\tlike: regget 0BB0 or regget 0c");
 	return;
 }
 
@@ -1152,7 +1153,7 @@ void parse_regset(void)
 	return;
 
 err:
-	cmd_error("usage: regset <hexvalue> <hexvalue>\n\tlike regset 0b abcd1234.");
+	cmd_error("regset <hexvalue> <hexvalue>\n\tlike regset 0b abcd1234.");
 }
 
 
@@ -1195,7 +1196,7 @@ void parse_sdsget(void)
 	return;
 
 err:
-	cmd_error("usage: sdsget <sds-id> <hex:page> <hex:reg>\n");
+	cmd_error("sdsget <sds-id> <hex:page> <hex:reg>\n");
 	return;
 }
 
@@ -1251,7 +1252,7 @@ void parse_sdsset(void)
 	return;
 
 err:
-	cmd_error("usage: sdsset <sds-id> <hex:page> <hex:reg> <hex:val>\n");
+	cmd_error("sdsset <sds-id> <hex:page> <hex:reg> <hex:val>\n");
 	return;
 }
 
@@ -1300,7 +1301,7 @@ void parse_phyget(void)
 	return;
 
 err:
-	cmd_error("usage: phyget <phy-id> <dev-id> <hex:reg>\n");
+	cmd_error("phyget <phy-id> <dev-id> <hex:reg>\n");
 	return;
 }
 
@@ -1360,7 +1361,7 @@ void parse_physet(void)
 	return;
 
 err:
-	cmd_error("usage: physet <phy-id> <dev-id> <hex:reg> <hex:val>\n");
+	cmd_error("physet <phy-id> <dev-id> <hex:reg> <hex:val>\n");
 	return;
 }
 
@@ -1529,7 +1530,7 @@ void parse_bw(void)
 	return;
 
 err:
-	cmd_error("usage: bw [in|out|status] <port> [<hexvalue>|off|drop|fc]\n");
+	cmd_error("bw [in|out|status] <port> [<hexvalue>|off|drop|fc]\n");
 }
 
 void parse_syslog(void)
@@ -1594,9 +1595,9 @@ void parse_syslog(void)
 	}
 	else
 	{
-		cmd_error("Error: syslog [on|off|ip [ip-address]|port [number]]\n");
+		cmd_error("syslog [on|off|ip [ip-address]|port [number]]\n"
-		print_string("  on/off enables or disables syslog, ip sets the syslog server IP address,\n");
+			  "  on/off enables or disables syslog, ip sets the syslog server IP address,\n"
-		print_string("  port sets the destination UDP port (default 514)\n");
+			  "  port sets the destination UDP port (default 514)\n");
 	}
 }
 
@@ -1811,7 +1812,7 @@ void cmd_parser(void) __banked
 			else if (cmd_compare(1, "show"))
 				igmp_show();
 			else {
-				cmd_error("Error: igmp on|off|show\n");
+				cmd_error("igmp on|off|show\n");
 			}
 		} else if (cmd_compare(0, "mac")) {
 			parse_mac_cmd();
@@ -1836,7 +1837,7 @@ void cmd_parser(void) __banked
 				}
 				*dst = NUL;
 			} else {
-				cmd_error("Error: hostname [name] - the name must not contain spaces\n");
+				cmd_error("hostname [name] - the name must not contain spaces\n");
 			}
 		} else if (cmd_compare(0, "stp")) {
 			stp_parse();
@@ -1845,7 +1846,7 @@ void cmd_parser(void) __banked
 			    && atoi_short(cmd_words_b[2]) && atoi_results_short && atoi_results_short <= 4094)
 				port_pvid_set(atoi_results_u8, atoi_results_short);
 			else {
-				cmd_error("Error: pvid <port> <1-4094>\n");
+				cmd_error("pvid <port> <1-4094>\n");
 			}
 		} else if (cmd_compare(0, "vlan")) {
 			parse_vlan();