Refactor febootstrap-supermin-helper code into separate files.

This is just code movement.  There is no change to the code.

1 files changed, 148 insertions, 0 deletions

diff --git a/helper/kernel.c b/helper/kernel.c
new file mode 100644
index 0000000..3301826
--- /dev/null
+++ b/helper/kernel.c
@@ -0,0 +1,148 @@
+/* febootstrap-supermin-helper reimplementation in C.
+ * Copyright (C) 2009-2010 Red Hat Inc.
+ *
+ * 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, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <config.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <fnmatch.h>
+#include <unistd.h>
+#include <errno.h>
+
+#include "error.h"
+#include "xvasprintf.h"
+
+#include "helper.h"
+
+/* Directory containing candidate kernels.  We could make this
+ * configurable at some point.
+ */
+#define KERNELDIR "/boot"
+#define MODULESDIR "/lib/modules"
+
+static char *
+get_modpath (const char *kernel_name)
+{
+  /* Ignore "vmlinuz-" at the beginning of the kernel name. */
+  const char *version = &kernel_name[8];
+
+  /* /lib/modules/<version> */
+  char *modpath = xasprintf (MODULESDIR "/%s", version);
+  if (!modpath) {
+    perror ("xasprintf");
+    exit (EXIT_FAILURE);
+  }
+
+  return modpath;
+}
+
+/* kernel_name is "vmlinuz-*".  Check if there is a corresponding
+ * module path in /lib/modules.
+ */
+static int
+has_modpath (const char *kernel_name)
+{
+  char *modpath = get_modpath (kernel_name);
+
+  if (verbose)
+    fprintf (stderr, "checking modpath %s is a directory\n", modpath);
+
+  int r = isdir (modpath);
+
+  if (r) {
+    if (verbose)
+      fprintf (stderr, "picked %s because modpath %s exists\n",
+               kernel_name, modpath);
+    free (modpath);
+    return 1;
+  }
+  else {
+    free (modpath);
+    return 0;
+  }
+}
+
+/* Create the kernel.  This chooses an appropriate kernel and makes a
+ * symlink to it.
+ *
+ * Look for the most recent kernel named vmlinuz-*.<arch>* which has a
+ * corresponding directory in /lib/modules/. If the architecture is
+ * x86, look for any x86 kernel.
+ *
+ * RHEL 5 didn't append the arch to the kernel name, so look for
+ * kernels without arch second.
+ *
+ * If no suitable kernel can be found, exit with an error.
+ *
+ * This function returns the module path (ie. /lib/modules/<version>).
+ */
+const char *
+create_kernel (const char *hostcpu, const char *kernel)
+{
+  char **all_files = read_dir (KERNELDIR);
+
+  /* In original: ls -1dvr /boot/vmlinuz-*.$arch* 2>/dev/null | grep -v xen */
+  const char *patt;
+  if (hostcpu[0] == 'i' && hostcpu[2] == '8' && hostcpu[3] == '6' &&
+      hostcpu[4] == '\0')
+    patt = "vmlinuz-*.i?86*";
+  else
+    patt = xasprintf ("vmlinuz-*.%s*", hostcpu);
+
+  char **candidates;
+  candidates = filter_fnmatch (all_files, patt, FNM_NOESCAPE);
+  candidates = filter_notmatching_substring (candidates, "xen");
+  candidates = filter (candidates, has_modpath);
+
+  if (candidates[0] == NULL) {
+    /* In original: ls -1dvr /boot/vmlinuz-* 2>/dev/null | grep -v xen */
+    patt = "vmlinuz-*";
+    candidates = filter_fnmatch (all_files, patt, FNM_NOESCAPE);
+    candidates = filter_notmatching_substring (candidates, "xen");
+    candidates = filter (candidates, has_modpath);
+
+    if (candidates[0] == NULL)
+      goto no_kernels;
+  }
+
+  sort (candidates, reverse_filevercmp);
+
+  /* Choose the first candidate. */
+  char *tmp = xasprintf (KERNELDIR "/%s", candidates[0]);
+
+  if (verbose)
+    fprintf (stderr, "creating symlink %s -> %s\n", kernel, tmp);
+
+  if (symlink (tmp, kernel) == -1)
+    error (EXIT_FAILURE, errno, "symlink kernel");
+
+  free (tmp);
+
+  return get_modpath (candidates[0]);
+
+  /* Print more diagnostics here than the old script did. */
+ no_kernels:
+  fprintf (stderr,
+           "febootstrap-supermin-helper: failed to find a suitable kernel.\n"
+           "I looked for kernels in " KERNELDIR " and modules in " MODULESDIR
+           ".\n"
+           "If this is a Xen guest, and you only have Xen domU kernels\n"
+           "installed, try installing a fullvirt kernel (only for\n"
+           "febootstrap use, you shouldn't boot the Xen guest with it).\n");
+  exit (EXIT_FAILURE);
+}