Add -f option for selecting the output format.

Only -f cpio is permitted by this commit.

2 files changed, 27 insertions, 3 deletions

diff --git a/helper/febootstrap-supermin-helper.pod b/helper/febootstrap-supermin-helper.pod
index 29f4b95..6a2551b 100644
--- a/helper/febootstrap-supermin-helper.pod
+++ b/helper/febootstrap-supermin-helper.pod
@@ -33,6 +33,11 @@ booting the appliance, and should be deleted straight afterwards.
 
 =over 4
 
+=item B<-f cpio> | B<--format cpio>
+
+Select the output format.  The default, and only possible output
+format, is C<cpio> (ie. a Linux initramfs).
+
 =item B<-k file> | B<--kmods file>
 
 If this option is specified, then C<file> should be a list of
diff --git a/helper/main.c b/helper/main.c
index a448b9e..f5a06cc 100644
--- a/helper/main.c
+++ b/helper/main.c
@@ -36,11 +36,14 @@
 struct timeval start_t;
 int verbose = 0;
 
+static const char *format = "cpio";
+
 enum { HELP_OPTION = CHAR_MAX + 1 };
 
-static const char *options = "k:vV";
+static const char *options = "f:k:vV";
 static const struct option long_options[] = {
   { "help", 0, 0, HELP_OPTION },
+  { "format", required_argument, 0, 'f' },
   { "kmods", required_argument, 0, 'k' },
   { "verbose", 0, 0, 'v' },
   { "version", 0, 0, 'V' },
@@ -68,6 +71,8 @@ usage (const char *progname)
           "Options:\n"
           "  --help\n"
           "       Display this help text and exit.\n"
+          "  -f cpio | --format cpio\n"
+          "       Specify output format (default: cpio).\n"
           "  -k file | --kmods file\n"
           "       Specify kernel module whitelist.\n"
           "  --verbose | -v\n"
@@ -95,6 +100,10 @@ main (int argc, char *argv[])
       usage (argv[0]);
       exit (EXIT_SUCCESS);
 
+    case 'f':
+      format = optarg;
+      break;
+
     case 'k':
       whitelist = optarg;
       break;
@@ -113,6 +122,17 @@ main (int argc, char *argv[])
     }
   }
 
+  /* Select the correct writer module. */
+  struct writer *writer;
+
+  if (strcmp (format, "cpio") == 0)
+    writer = &cpio_writer;
+  else {
+    fprintf (stderr, "%s: incorrect output format (-f): must be cpio\n",
+             argv[0]);
+    exit (EXIT_FAILURE);
+  }
+
   char **inputs = &argv[optind];
   int nr_inputs = argc - optind - 3;
 
@@ -152,8 +172,7 @@ main (int argc, char *argv[])
     print_timestamped_message ("finished creating kernel");
 
   /* Create the appliance. */
-  create_appliance (inputs, nr_inputs, whitelist, modpath, appliance,
-                    &cpio_writer);
+  create_appliance (inputs, nr_inputs, whitelist, modpath, appliance, writer);
 
   if (verbose)
     print_timestamped_message ("finished creating appliance");