QemuOpts: add -set option

One use case will be file for drives (no filename quoting issues), i.e.

	-drive id=test,if=virtio
	-set drive.test.file=/vmdisk/test-virtio.img

It will work for any other option (assuming handled by QemuOpts) though.
Except for id= for obvious reasons ;).
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>
Message-Id: 

qemu-config.c

@@ -71,3 +71,44 @@ QemuOptsList qemu_drive_opts = {
     },
 };
 
+static QemuOptsList *lists[] = {
+    &qemu_drive_opts,
+    NULL,
+};
+
+int qemu_set_option(const char *str)
+{
+    char group[64], id[64], arg[64];
+    QemuOpts *opts;
+    int i, rc, offset;
+
+    rc = sscanf(str, "%63[^.].%63[^.].%63[^=]%n", group, id, arg, &offset);
+    if (rc < 3 || str[offset] != '=') {
+        fprintf(stderr, "can't parse: \"%s\"\n", str);
+        return -1;
+    }
+
+    for (i = 0; lists[i] != NULL; i++) {
+        if (strcmp(lists[i]->name, group) == 0)
+            break;
+    }
+    if (lists[i] == NULL) {
+        fprintf(stderr, "there is no option group \"%s\"\n", group);
+        return -1;
+    }
+
+    opts = qemu_opts_find(lists[i], id);
+    if (!opts) {
+        fprintf(stderr, "there is no %s \"%s\" defined\n",
+                lists[i]->name, id);
+        return -1;
+    }
+
+    if (-1 == qemu_opt_set(opts, arg, str+offset+1)) {
+        fprintf(stderr, "failed to set \"%s\" for %s \"%s\"\n",
+                arg, lists[i]->name, id);
+        return -1;
+    }
+    return 0;
+}
+

qemu-config.h

 extern QemuOptsList qemu_drive_opts;
+
+int qemu_set_option(const char *str);

qemu-options.hx

@@ -95,8 +95,12 @@ DEF("drive", HAS_ARG, QEMU_OPTION_drive,
     "-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n"
     "       [,cyls=c,heads=h,secs=s[,trans=t]][,snapshot=on|off]\n"
     "       [,cache=writethrough|writeback|none][,format=f][,serial=s]\n"
-    "       [,addr=A]\n"
+    "       [,addr=A][,id=name]\n"
     "                use 'file' as a drive image\n")
+DEF("set", HAS_ARG, QEMU_OPTION_set,
+    "-set group.id.arg=value\n"
+    "                set <arg> parameter for item <id> of type <group>\n"
+    "                i.e. -set drive.$id.file=/path/to/image\n")
 STEXI
 @item -drive @var{option}[,@var{option}[,@var{option}[,...]]]
 

vl.c

@@ -4966,6 +4966,10 @@ int main(int argc, char **argv, char **envp)
             case QEMU_OPTION_drive:
                 drive_add(NULL, "%s", optarg);
 	        break;
+            case QEMU_OPTION_set:
+                if (qemu_set_option(optarg) != 0)
+                    exit(1);
+	        break;
             case QEMU_OPTION_mtdblock:
                 drive_add(optarg, MTD_ALIAS);
                 break;