1 files changed, 159 insertions, 0 deletions
diff --git a/gnomeos/yocto/recipies-core/ostree-init/ostree-init.c b/gnomeos/yocto/recipies-core/ostree-init/ostree-init.c
new file mode 100644
index 00000000..deeb330a
--- /dev/null
+++ b/gnomeos/yocto/recipies-core/ostree-init/ostree-init.c
@@ -0,0 +1,159 @@
+/* -*- c-file-style: "gnu" -*-
+ * ostree-init.c - switch to new root directory and start init.
+ * Copyright 2011 Colin Walters <walters@verbum.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+#define _GNU_SOURCE
+#include <sys/mount.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/param.h>
+#include <fcntl.h>
+#include <assert.h>
+#include <stdio.h>
+#include <stdarg.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <errno.h>
+#include <ctype.h>
+#include <dirent.h>
+
+#define INIT_PATH "/sbin/init"
+
+static int
+perrorv (const char *format, ...) __attribute__ ((format (printf, 1, 2)));
+
+static int
+perrorv (const char *format, ...)
+{
+  va_list args;
+  char buf[PATH_MAX];
+  char *p;
+
+  p = strerror_r (errno, buf, sizeof (buf));
+
+  va_start (args, format);
+
+  vfprintf (stderr, format, args);
+  fprintf (stderr, ": %s\n", p);
+  fflush (stderr);
+
+  va_end (args);
+
+  sleep (3);
+	
+  return 0;
+}
+
+int main(int argc, char *argv[])
+{
+  FILE *cmdline_f = NULL;
+  const char *ostree_root = NULL;
+  const char *p = NULL;
+  size_t bytes_read;
+  size_t buf_size;
+  size_t buf_used;
+  char destpath[PATH_MAX];
+  char *buf;
+  struct stat stbuf;
+  char **init_argv = NULL;
+  int i;
+
+  cmdline_f = fopen ("/proc/cmdline", "r");
+  if (!cmdline_f)
+    {
+      perrorv ("Failed to open /proc/cmdline");
+      return 1;
+    }
+
+  buf_size = 8;
+  buf_used = 0;
+  buf = malloc (buf_size);
+  assert (buf);
+
+  while ((bytes_read = fread (buf + buf_used, 1, buf_size - buf_used, cmdline_f)) > 0)
+    {
+      buf_used += bytes_read;
+      if (buf_size == buf_used)
+	{
+	  buf_size *= 2;
+	  buf = realloc (buf, buf_size);
+	  assert (buf);
+	}
+    }
+  if (bytes_read < 0)
+    {
+      perrorv ("Failed to read from /proc/cmdline");
+      exit (1);
+    }
+
+  for (p = buf; *p; p += strlen (p) + 1)
+    {
+      if (!strcmp (p, "ostree="))
+	{
+	  ostree_root = p + strlen ("ostree=");
+	  break;
+	}
+    }
+
+  if (ostree_root)
+    {
+      snprintf (destpath, sizeof(destpath), "/ostree/%s", ostree_root);
+      if (stat (destpath, &stbuf) < 0)
+	{
+	  perrorv ("Invalid ostree root '%s'", destpath);
+	  exit (1);
+	}
+
+      snprintf (destpath, sizeof(destpath), "/ostree/%s/sysroot", ostree_root);
+      if (mount ("/", destpath, NULL, MS_BIND, NULL) < 0)
+	{
+	  perrorv ("Failed to bind mount / to '%s'", destpath);
+	  exit (1);
+	}
+
+      snprintf (destpath, sizeof(destpath), "/ostree/%s", ostree_root);
+      if (chroot (destpath) < 0)
+	{
+	  perrorv ("failed to change root to '%s'", destpath);
+	  exit (1);
+	}
+
+      if (chdir ("/") < 0)
+	{
+	  perrorv ("failed to chdir to subroot");
+	  exit (1);
+	}
+      
+    }
+  else
+    {
+      fprintf (stderr, "No ostree= argument specified\n");
+      exit (1);
+    }
+
+  init_argv = malloc (sizeof (char*)*(argc+1));
+  init_argv[0] = INIT_PATH;
+  for (i = 1; i < argc; i++)
+    init_argv[i] = argv[i];
+  init_argv[i] = NULL;
+  
+  execv (INIT_PATH, init_argv);
+  perrorv ("Failed to exec init '%s'", INIT_PATH);
+  exit (1);
+}
+