1 files changed, 296 insertions, 0 deletions
diff --git a/g13/backend.c b/g13/backend.c
new file mode 100644
index 0000000..a0a2675
--- /dev/null
+++ b/g13/backend.c
@@ -0,0 +1,296 @@
+/* backend.c - Dispatcher to the various backends.
+ * Copyright (C) 2009 Free Software Foundation, Inc.
+ *
+ * This file is part of GnuPG.
+ *
+ * GnuPG 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 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GnuPG 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 <https://www.gnu.org/licenses/>.
+ */
+
+#include <config.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <unistd.h>
+#include <sys/stat.h>
+
+#include "g13.h"
+#include "../common/i18n.h"
+#include "../common/sysutils.h"
+#include "keyblob.h"
+#include "backend.h"
+#include "be-encfs.h"
+#include "be-truecrypt.h"
+#include "be-dmcrypt.h"
+#include "call-syshelp.h"
+
+#define no_such_backend(a) _no_such_backend ((a), __func__)
+static gpg_error_t
+_no_such_backend (int conttype, const char *func)
+{
+  log_error ("invalid backend %d given in %s - this is most likely a bug\n",
+             conttype, func);
+  return gpg_error (GPG_ERR_INTERNAL);
+}
+
+
+/* Parse NAME and return the corresponding content type.  If the name
+   is not known, a error message is printed and zero returned.  If
+   NAME is NULL the supported backend types are listed and 0 is
+   returned. */
+int
+be_parse_conttype_name (const char *name)
+{
+  static struct { const char *name; int conttype; } names[] = {
+    { "encfs",    CONTTYPE_ENCFS },
+    { "dm-crypt", CONTTYPE_DM_CRYPT }
+  };
+  int i;
+
+  if (!name)
+    {
+      log_info ("Known backend types:\n");
+      for (i=0; i < DIM (names); i++)
+        log_info ("    %s\n", names[i].name);
+      return 0;
+    }
+
+  for (i=0; i < DIM (names); i++)
+    {
+      if (!strcmp (names[i].name, name))
+        return names[i].conttype;
+    }
+
+  log_error ("invalid backend type '%s' given\n", name);
+  return 0;
+}
+
+
+/* Return true if CONTTYPE is supported by us.  */
+int
+be_is_supported_conttype (int conttype)
+{
+  switch (conttype)
+    {
+    case CONTTYPE_ENCFS:
+    case CONTTYPE_DM_CRYPT:
+      return 1;
+
+    default:
+      return 0;
+    }
+}
+
+
+/* Create a lock file for the container FNAME and store the lock at
+ * R_LOCK and return 0.  On error return an error code and store NULL
+ * at R_LOCK.  */
+gpg_error_t
+be_take_lock_for_create (ctrl_t ctrl, const char *fname, dotlock_t *r_lock)
+{
+  gpg_error_t err;
+  dotlock_t lock = NULL;
+  struct stat sb;
+
+  *r_lock = NULL;
+
+  /* A DM-crypt container requires special treatment by using the
+     syshelper functions.  */
+  if (ctrl->conttype == CONTTYPE_DM_CRYPT)
+    {
+      /*  */
+      err = call_syshelp_set_device (ctrl, fname);
+      goto leave;
+    }
+
+
+  /* A quick check to see that no container with that name already
+     exists.  */
+  if (!gnupg_access (fname, F_OK))
+    {
+      err = gpg_error (GPG_ERR_EEXIST);
+      goto leave;
+    }
+
+  /* Take a lock and proceed with the creation.  If there is a lock we
+     immediately return an error because for creation it does not make
+     sense to wait.  */
+  lock = dotlock_create (fname, 0);
+  if (!lock)
+    {
+      err = gpg_error_from_syserror ();
+      goto leave;
+    }
+  if (dotlock_take (lock, 0))
+    {
+      err = gpg_error_from_syserror ();
+      goto leave;
+    }
+
+  /* Check again that the file does not exist.  */
+  err = gnupg_stat (fname, &sb)? 0 : gpg_error (GPG_ERR_EEXIST);
+
+ leave:
+  if (!err)
+    {
+      *r_lock = lock;
+      lock = NULL;
+    }
+  dotlock_destroy (lock);
+  return err;
+}
+
+
+/* If the backend requires a separate file or directory for the
+   container, return its name by computing it from FNAME which gives
+   the g13 filename.  The new file name is allocated and stored at
+   R_NAME, if this is expected to be a directory true is stored at
+   R_ISDIR.  If no detached name is expected or an error occurs NULL
+   is stored at R_NAME. The function returns 0 on success or an error
+   code.  */
+gpg_error_t
+be_get_detached_name (int conttype, const char *fname,
+                      char **r_name, int *r_isdir)
+{
+  *r_name = NULL;
+  *r_isdir = 0;
+  switch (conttype)
+    {
+    case CONTTYPE_ENCFS:
+      return be_encfs_get_detached_name (fname, r_name, r_isdir);
+
+    case CONTTYPE_DM_CRYPT:
+      return 0;
+
+    default:
+      return no_such_backend (conttype);
+    }
+}
+
+
+gpg_error_t
+be_create_new_keys (int conttype, membuf_t *mb)
+{
+  switch (conttype)
+    {
+    case CONTTYPE_ENCFS:
+      return be_encfs_create_new_keys (mb);
+
+    case CONTTYPE_TRUECRYPT:
+      return be_truecrypt_create_new_keys (mb);
+
+    case CONTTYPE_DM_CRYPT:
+      return 0;
+
+    default:
+      return no_such_backend (conttype);
+    }
+}
+
+
+/* Dispatcher to the backend's create function.  */
+gpg_error_t
+be_create_container (ctrl_t ctrl, int conttype,
+                     const char *fname, int fd, tupledesc_t tuples,
+                     unsigned int *r_id)
+{
+  (void)fd;  /* Not yet used.  */
+
+  switch (conttype)
+    {
+    case CONTTYPE_ENCFS:
+      return be_encfs_create_container (ctrl, fname, tuples, r_id);
+
+    case CONTTYPE_DM_CRYPT:
+      return be_dmcrypt_create_container (ctrl);
+
+    default:
+      return no_such_backend (conttype);
+    }
+}
+
+
+/* Dispatcher to the backend's mount function.  */
+gpg_error_t
+be_mount_container (ctrl_t ctrl, int conttype,
+                    const char *fname,  const char *mountpoint,
+                    tupledesc_t tuples, unsigned int *r_id)
+{
+  switch (conttype)
+    {
+    case CONTTYPE_ENCFS:
+      return be_encfs_mount_container (ctrl, fname, mountpoint, tuples, r_id);
+
+    case CONTTYPE_DM_CRYPT:
+      return be_dmcrypt_mount_container (ctrl, fname, mountpoint, tuples);
+
+    default:
+      return no_such_backend (conttype);
+    }
+}
+
+
+/* Dispatcher to the backend's umount function.  */
+gpg_error_t
+be_umount_container (ctrl_t ctrl, int conttype, const char *fname)
+{
+  switch (conttype)
+    {
+    case CONTTYPE_ENCFS:
+      return gpg_error (GPG_ERR_NOT_SUPPORTED);
+
+    case CONTTYPE_DM_CRYPT:
+      return be_dmcrypt_umount_container (ctrl, fname);
+
+    default:
+      return no_such_backend (conttype);
+    }
+}
+
+
+/* Dispatcher to the backend's suspend function.  */
+gpg_error_t
+be_suspend_container (ctrl_t ctrl, int conttype, const char *fname)
+{
+  switch (conttype)
+    {
+    case CONTTYPE_ENCFS:
+      return gpg_error (GPG_ERR_NOT_SUPPORTED);
+
+    case CONTTYPE_DM_CRYPT:
+      return be_dmcrypt_suspend_container (ctrl, fname);
+
+    default:
+      return no_such_backend (conttype);
+    }
+}
+
+
+/* Dispatcher to the backend's resume function.  */
+gpg_error_t
+be_resume_container (ctrl_t ctrl, int conttype, const char *fname,
+                     tupledesc_t tuples)
+{
+  switch (conttype)
+    {
+    case CONTTYPE_ENCFS:
+      return gpg_error (GPG_ERR_NOT_SUPPORTED);
+
+    case CONTTYPE_DM_CRYPT:
+      return be_dmcrypt_resume_container (ctrl, fname, tuples);
+
+    default:
+      return no_such_backend (conttype);
+    }
+}