QemuOpts: command line switches for the config file.

Adds -readconfig and -writeconfig command line switches to read/write
QemuOpts from config file.

In theory you should be able to do:

  qemu < machine config cmd line switches here > -writeconfig vm.cfg
  qemu -readconfig vm.cfg

In practice it will not work.  Not all command line switches are
converted to QemuOpts, so you'll have to keep the not-yet converted ones
on the second line.  Also there might be bugs lurking which prevent even
the converted ones from working correctly.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

1 files changed, 30 insertions, 0 deletions

diff --git a/vl.c b/vl.c
index 402e78d..bf91ee1 100644
--- a/vl.c
+++ b/vl.c
@@ -5364,6 +5364,36 @@ int main(int argc, char **argv, char **envp)
                 xen_mode = XEN_ATTACH;
                 break;
 #endif
+            case QEMU_OPTION_readconfig:
+                {
+                    FILE *fp;
+                    fp = fopen(optarg, "r");
+                    if (fp == NULL) {
+                        fprintf(stderr, "open %s: %s\n", optarg, strerror(errno));
+                        exit(1);
+                    }
+                    if (qemu_config_parse(fp) != 0) {
+                        exit(1);
+                    }
+                    fclose(fp);
+                    break;
+                }
+            case QEMU_OPTION_writeconfig:
+                {
+                    FILE *fp;
+                    if (strcmp(optarg, "-") == 0) {
+                        fp = stdout;
+                    } else {
+                        fp = fopen(optarg, "w");
+                        if (fp == NULL) {
+                            fprintf(stderr, "open %s: %s\n", optarg, strerror(errno));
+                            exit(1);
+                        }
+                    }
+                    qemu_config_write(fp);
+                    fclose(fp);
+                    break;
+                }
             }
         }
     }