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Diffstat (limited to 'g13/sh-blockdev.c')
| -rw-r--r-- | g13/sh-blockdev.c | 151 |
1 files changed, 151 insertions, 0 deletions
diff --git a/g13/sh-blockdev.c b/g13/sh-blockdev.c new file mode 100644 index 000000000..2d431ea24 --- /dev/null +++ b/g13/sh-blockdev.c @@ -0,0 +1,151 @@ +/* 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 <http://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 "i18n.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 = sh_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 = sh_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 = sh_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; +} |