machinectl: tweak address output in "machinectl status"

With this change we'll not show an "Addresses" field for machines that
we don't know any addresses for.

This changes print_addresses() to never suffix its output with a
newline, leaving that to the caller. That's a good idea since depending
on who the caller is, different rules apply: if no addresses are found,
then the list view still wants a newline, but the status view does not.

This also changes the function to return the number of found addresses,
which can be used to decide when to add a newline or not.

Author: poettering

src/machine/machinectl.c

@@ -327,8 +327,10 @@ static int list_machines(int argc, char *argv[], void *userdata) {
                        (int) max_version_id, strdash_if_empty(machines[j].version_id));
 
                 r = print_addresses(bus, machines[j].name, 0, "", prefix, arg_addrs);
-                if (r == -EOPNOTSUPP)
-                        printf("-\n");
+                if (r <= 0) /* error or no addresses defined? */
+                        fputs("-\n", stdout);
+                else
+                        fputc('\n', stdout);
         }
 
         if (arg_legend) {
@@ -520,6 +522,7 @@ static int print_addresses(sd_bus *bus, const char *name, int ifi, const char *p
         _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
         _cleanup_free_ char *addresses = NULL;
         bool truncate = false;
+        unsigned n = 0;
         int r;
 
         assert(bus);
@@ -567,7 +570,7 @@ static int print_addresses(sd_bus *bus, const char *name, int ifi, const char *p
                         else
                                 strcpy(buf_ifi, "");
 
-                        if(!strextend(&addresses, prefix, inet_ntop(family, a, buffer, sizeof(buffer)), buf_ifi, NULL))
+                        if (!strextend(&addresses, prefix, inet_ntop(family, a, buffer, sizeof(buffer)), buf_ifi, NULL))
                                 return log_oom();
                 } else
                         truncate = true;
@@ -581,6 +584,8 @@ static int print_addresses(sd_bus *bus, const char *name, int ifi, const char *p
 
                 if (n_addr > 0)
                         n_addr -= 1;
+
+                n++;
         }
         if (r < 0)
                 return bus_log_parse_error(r);
@@ -589,8 +594,10 @@ static int print_addresses(sd_bus *bus, const char *name, int ifi, const char *p
         if (r < 0)
                 return bus_log_parse_error(r);
 
-        fprintf(stdout, "%s%s\n", addresses, truncate ? "..." : "");
-        return 0;
+        if (n > 0)
+                fprintf(stdout, "%s%s", addresses, truncate ? "..." : "");
+
+        return (int) n;
 }
 
 static int print_os_release(sd_bus *bus, const char *method, const char *name, const char *prefix) {
@@ -738,10 +745,11 @@ static void print_machine_status_info(sd_bus *bus, MachineStatusInfo *i) {
                 fputc('\n', stdout);
         }
 
-        print_addresses(bus, i->name, ifi,
-                       "\t Address: ",
-                       "\n\t          ",
-                       ALL_IP_ADDRESSES);
+        if (print_addresses(bus, i->name, ifi,
+                            "\t Address: ",
+                            "\n\t          ",
+                            ALL_IP_ADDRESSES) > 0)
+                fputc('\n', stdout);
 
         print_os_release(bus, "GetMachineOSRelease", i->name, "\t      OS: ");