New APIs: Support for opening LUKS-encrypted disks.

[libguestfs.git] / daemon / luks.c

diff --git a/daemon/luks.c b/daemon/luks.c
new file mode 100644 (file)
index 0000000..f5a0b9d
--- /dev/null
+++ b/daemon/luks.c
@@ -0,0 +1,138 @@
+/* libguestfs - the guestfsd daemon
+ * Copyright (C) 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 <string.h>
+
+#include "daemon.h"
+#include "c-ctype.h"
+#include "actions.h"
+#include "optgroups.h"
+
+int
+optgroup_luks_available (void)
+{
+  return prog_exists ("cryptsetup");
+}
+
+static int
+luks_open (const char *device, const char *key, const char *mapname,
+           int readonly)
+{
+  /* Sanity check: /dev/mapper/mapname must not exist already.  Note
+   * that the device-mapper control device (/dev/mapper/control) is
+   * always there, so you can't ever have mapname == "control".
+   */
+  size_t len = strlen (mapname);
+  char devmapper[len+32];
+  snprintf (devmapper, len+32, "/dev/mapper/%s", mapname);
+  if (access (devmapper, F_OK) == 0) {
+    reply_with_error ("%s: device already exists", devmapper);
+    return -1;
+  }
+
+  char tempfile[] = "/tmp/luksXXXXXX";
+  int fd = mkstemp (tempfile);
+  if (fd == -1) {
+    reply_with_perror ("mkstemp");
+    return -1;
+  }
+
+  len = strlen (key);
+  if (xwrite (fd, key, len) == -1) {
+    reply_with_perror ("write");
+    close (fd);
+    unlink (tempfile);
+    return -1;
+  }
+
+  if (close (fd) == -1) {
+    reply_with_perror ("close");
+    unlink (tempfile);
+    return -1;
+  }
+
+  const char *argv[16];
+  size_t i = 0;
+
+  argv[i++] = "cryptsetup";
+  argv[i++] = "-d";
+  argv[i++] = tempfile;
+  if (readonly) argv[i++] = "--readonly";
+  argv[i++] = "luksOpen";
+  argv[i++] = device;
+  argv[i++] = mapname;
+  argv[i++] = NULL;
+
+  char *err;
+  int r = commandv (NULL, &err, (const char * const *) argv);
+  unlink (tempfile);
+
+  if (r == -1) {
+    reply_with_error ("%s", err);
+    free (err);
+    return -1;
+  }
+
+  free (err);
+
+  udev_settle ();
+
+  return 0;
+}
+
+int
+do_luks_open (const char *device, const char *key, const char *mapname)
+{
+  return luks_open (device, key, mapname, 0);
+}
+
+int
+do_luks_open_ro (const char *device, const char *key, const char *mapname)
+{
+  return luks_open (device, key, mapname, 1);
+}
+
+int
+do_luks_close (const char *device)
+{
+  /* Must be /dev/mapper/... */
+  if (! STRPREFIX (device, "/dev/mapper/")) {
+    reply_with_error ("luks_close: you must call this on the /dev/mapper device created by luks_open");
+    return -1;
+  }
+
+  const char *mapname = &device[12];
+
+  char *err;
+  int r = command (NULL, &err, "cryptsetup", "luksClose", mapname, NULL);
+  if (r == -1) {
+    reply_with_error ("%s", err);
+    free (err);
+    return -1;
+  }
+
+  free (err);
+
+  udev_settle ();
+
+  return 0;
+}