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-rw-r--r--g13/sh-blockdev.c152
1 files changed, 152 insertions, 0 deletions
diff --git a/g13/sh-blockdev.c b/g13/sh-blockdev.c
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+/* sh-blockdev.c - Block device functions for g13-syshelp
+ * Copyright (C) 2015 Werner Koch
+ *
+ * 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 <stdarg.h>
+#include <errno.h>
+#include <assert.h>
+#include <limits.h>
+
+#include "g13-syshelp.h"
+#include <assuan.h>
+#include "../common/i18n.h"
+#include "../common/exectool.h"
+#include "keyblob.h"
+
+#ifndef HAVE_STRTOULL
+# error building this tool requires strtoull(3)
+#endif
+#ifndef ULLONG_MAX
+# error ULLONG_MAX missing
+#endif
+
+
+/* Return the size measured in the number of 512 byte sectors for the
+ block device NAME. */
+gpg_error_t
+sh_blockdev_getsz (const char *name, unsigned long long *r_nblocks)
+{
+ gpg_error_t err;
+ const char *argv[3];
+ char *result;
+
+ *r_nblocks = 0;
+ argv[0] = "--getsz";
+ argv[1] = name;
+ argv[2] = NULL;
+ err = gnupg_exec_tool ("/sbin/blockdev", argv, NULL, &result, NULL);
+ if (!err)
+ {
+ gpg_err_set_errno (0);
+ *r_nblocks = strtoull (result, NULL, 10);
+ if (*r_nblocks == ULLONG_MAX && errno)
+ {
+ err = gpg_error_from_syserror ();
+ *r_nblocks = 0;
+ }
+ xfree (result);
+ }
+ return err;
+}
+
+
+/* Return 0 if the device NAME looks like an empty partition. */
+gpg_error_t
+sh_is_empty_partition (const char *name)
+{
+ gpg_error_t err;
+ const char *argv[6];
+ char *buffer;
+ estream_t fp;
+ char *p;
+ size_t nread;
+
+ argv[0] = "-o";
+ argv[1] = "value";
+ argv[2] = "-s";
+ argv[3] = "UUID";
+ argv[4] = name;
+ argv[5] = NULL;
+ err = gnupg_exec_tool ("/sbin/blkid", argv, NULL, &buffer, NULL);
+ if (err)
+ return gpg_error (GPG_ERR_FALSE);
+ if (*buffer)
+ {
+ /* There seems to be an UUID - thus we have a file system. */
+ xfree (buffer);
+ return gpg_error (GPG_ERR_FALSE);
+ }
+ xfree (buffer);
+
+ argv[0] = "-o";
+ argv[1] = "value";
+ argv[2] = "-s";
+ argv[3] = "PARTUUID";
+ argv[4] = name;
+ argv[5] = NULL;
+ err = gnupg_exec_tool ("/sbin/blkid", argv, NULL, &buffer, NULL);
+ if (err)
+ return gpg_error (GPG_ERR_FALSE);
+ if (!*buffer)
+ {
+ /* If there is no PARTUUID we assume that name has already a
+ mapped partition. */
+ xfree (buffer);
+ return gpg_error (GPG_ERR_FALSE);
+ }
+ xfree (buffer);
+
+ /* As a safeguard we require that the first 32k of a partition are
+ all zero before we assume the partition is empty. */
+ buffer = xtrymalloc (32 * 1024);
+ if (!buffer)
+ return gpg_error_from_syserror ();
+ fp = es_fopen (name, "rb,samethread");
+ if (!fp)
+ {
+ err = gpg_error_from_syserror ();
+ log_error ("error opening '%s': %s\n", name, gpg_strerror (err));
+ xfree (buffer);
+ return gpg_error (GPG_ERR_FALSE);
+ }
+ if (es_read (fp, buffer, 32 * 1024, &nread))
+ err = gpg_error_from_syserror ();
+ else if (nread != 32 *1024)
+ err = gpg_error (GPG_ERR_TOO_SHORT);
+ else
+ err = 0;
+ es_fclose (fp);
+ if (err)
+ {
+ log_error ("error reading the first 32 KiB from '%s': %s\n",
+ name, gpg_strerror (err));
+ xfree (buffer);
+ return err;
+ }
+ for (p=buffer; nread && !*p; nread--, p++)
+ ;
+ xfree (buffer);
+ if (nread)
+ return gpg_error (GPG_ERR_FALSE); /* No all zeroes. */
+
+ return 0;
+}