xl: Add "xl domid" command, a clone of "xm domid".

Signed-off-by: Yang Hongyang <yanghy@cn.fujitsu.com>

tools/libxl/xl_cmdimpl.c

@@ -1237,6 +1237,9 @@ void help(char *command)
         printf("  -d DOMAIN, --domain=DOMAIN     Domain to modify\n");
         printf("  -w WEIGHT, --weight=WEIGHT     Weight (int)\n");
         printf("  -c CAP, --cap=CAP              Cap (int)\n");
+    } else if (!strcmp(command, "domid")) {
+        printf("Usage: xl domid <DomainName>\n\n");
+        printf("Convert a domain name to domain id.\n");
     }
 }
 
@@ -2961,3 +2964,36 @@ int main_sched_credit(int argc, char **argv)
 
     exit(0);
 }
+
+int main_domid(int argc, char **argv)
+{
+    int opt;
+    char *domname = NULL;
+
+    while ((opt = getopt(argc, argv, "h")) != -1) {
+        switch (opt) {
+        case 'h':
+            help("domid");
+            exit(0);
+        default:
+            fprintf(stderr, "option `%c' not supported.\n", opt);
+            break;
+        }
+    }
+
+    domname = argv[optind];
+    if (!domname) {
+        fprintf(stderr, "Must specify a domain name.\n\n");
+        help("domid");
+        exit(1);
+    }
+
+    if (libxl_name_to_domid(&ctx, domname, &domid)) {
+        fprintf(stderr, "Can't get domid of domain name '%s', maybe this domain does not exist.\n", domname);
+        exit(1);
+    }
+
+    printf("%d\n", domid);
+
+    exit(0);
+}

tools/libxl/xl_cmdimpl.h

@@ -35,5 +35,6 @@ int main_vcpupin(int argc, char **argv);
 int main_vcpuset(int argc, char **argv);
 int main_memset(int argc, char **argv);
 int main_sched_credit(int argc, char **argv);
+int main_domid(int argc, char **argv);
 
 void help(char *command);

tools/libxl/xl_cmdtable.c

@@ -35,7 +35,8 @@ struct cmd_spec cmd_table[] = {
     { "vcpu-set", &main_vcpuset, "set the number of active VCPUs allowed for the domain" },
     { "list-vm", &main_list_vm, "list the VMs,without DOM0" },
     { "info", &main_info, "get information about Xen host" },
-    { "sched-credit", &main_sched_credit, "get/set credit scheduler parameters" }
+    { "sched-credit", &main_sched_credit, "get/set credit scheduler parameters" },
+    { "domid", &main_domid, "convert a domain name to domain id"},
 };
 
 int cmdtable_len = sizeof(cmd_table)/sizeof(struct cmd_spec);