Fixed the build error for riscv64 arch using gcc 13
[platform/upstream/cryptsetup.git] / lib / utils.c
index e1d0e4a..7e850a6 100644 (file)
+/*
+ * utils - miscellaneous device utilities for cryptsetup
+ *
+ * Copyright (C) 2004 Jana Saout <jana@saout.de>
+ * Copyright (C) 2004-2007 Clemens Fruhwirth <clemens@endorphin.org>
+ * Copyright (C) 2009-2021 Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2009-2021 Milan Broz
+ *
+ * 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
 #include <stdio.h>
-#include <string.h>
-#include <stdlib.h>
-#include <stddef.h>
-#include <stdarg.h>
 #include <errno.h>
-#include <linux/fs.h>
-#include <sys/types.h>
-#include <unistd.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <sys/ioctl.h>
-#include <fcntl.h>
 #include <sys/mman.h>
 #include <sys/resource.h>
+#include <sys/stat.h>
+#include <sys/utsname.h>
 
-#include "libcryptsetup.h"
 #include "internal.h"
 
-static char *error=NULL;
-
-void set_error_va(const char *fmt, va_list va)
-{
-       int r;
-
-       if(error) {
-               free(error);
-               error = NULL;
-       }
-
-       if(!fmt) return;
-
-       r = vasprintf(&error, fmt, va);
-       if (r < 0) {
-               free(error);
-               error = NULL;
-               return;
-       }
-
-       if (r && error[r - 1] == '\n')
-               error[r - 1] = '\0';
-}
-
-void set_error(const char *fmt, ...)
-{
-       va_list va;
-
-       va_start(va, fmt);
-       set_error_va(fmt, va);
-       va_end(va);
-}
-
-const char *get_error(void)
+size_t crypt_getpagesize(void)
 {
-       return error;
+       long r = sysconf(_SC_PAGESIZE);
+       return r <= 0 ? DEFAULT_MEM_ALIGNMENT : (size_t)r;
 }
 
-static int get_alignment(int fd)
+unsigned crypt_cpusonline(void)
 {
-       int alignment = DEFAULT_MEM_ALIGNMENT;
-
-#ifdef _PC_REC_XFER_ALIGN
-       alignment = fpathconf(fd, _PC_REC_XFER_ALIGN);
-       if (alignment < 0)
-               alignment = DEFAULT_MEM_ALIGNMENT;
-#endif
-       return alignment;
+       long r = sysconf(_SC_NPROCESSORS_ONLN);
+       return r < 0 ? 1 : r;
 }
 
-static void *aligned_malloc(void **base, int size, int alignment)
+uint64_t crypt_getphysmemory_kb(void)
 {
-#ifdef HAVE_POSIX_MEMALIGN
-       return posix_memalign(base, alignment, size) ? NULL : *base;
-#else
-/* Credits go to Michal's padlock patches for this alignment code */
-       char *ptr;
-
-       ptr  = malloc(size + alignment);
-       if(ptr == NULL) return NULL;
-
-       *base = ptr;
-       if(alignment > 1 && ((long)ptr & (alignment - 1))) {
-               ptr += alignment - ((long)(ptr) & (alignment - 1));
-       }
-       return ptr;
-#endif
-}
-static int sector_size(int fd) 
-{
-       int bsize;
-       if (ioctl(fd,BLKSSZGET, &bsize) < 0)
-               return -EINVAL;
-       else
-               return bsize;
-}
+       long pagesize, phys_pages;
+       uint64_t phys_memory_kb;
 
-int sector_size_for_device(const char *device)
-{
-       int fd = open(device, O_RDONLY);
-       int r;
-       if(fd < 0)
-               return -EINVAL;
-       r = sector_size(fd);
-       close(fd);
-       return r;
-}
+       pagesize = sysconf(_SC_PAGESIZE);
+       phys_pages = sysconf(_SC_PHYS_PAGES);
 
-ssize_t write_blockwise(int fd, const void *orig_buf, size_t count)
-{
-       void *hangover_buf, *hangover_buf_base = NULL;
-       void *buf, *buf_base = NULL;
-       int r, hangover, solid, bsize, alignment;
-       ssize_t ret = -1;
-
-       if ((bsize = sector_size(fd)) < 0)
-               return bsize;
-
-       hangover = count % bsize;
-       solid = count - hangover;
-       alignment = get_alignment(fd);
-
-       if ((long)orig_buf & (alignment - 1)) {
-               buf = aligned_malloc(&buf_base, count, alignment);
-               if (!buf)
-                       goto out;
-               memcpy(buf, orig_buf, count);
-       } else
-               buf = (void *)orig_buf;
+       if (pagesize < 0 || phys_pages < 0)
+               return 0;
 
-       r = write(fd, buf, solid);
-       if (r < 0 || r != solid)
-               goto out;
+       phys_memory_kb = pagesize / 1024;
+       phys_memory_kb *= phys_pages;
 
-       if (hangover) {
-               hangover_buf = aligned_malloc(&hangover_buf_base, bsize, alignment);
-               if (!hangover_buf)
-                       goto out;
+       return phys_memory_kb;
+}
 
-               r = read(fd, hangover_buf, bsize);
-               if(r < 0 || r != bsize) goto out;
+/* MEMLOCK */
+#define DEFAULT_PROCESS_PRIORITY -18
 
-               r = lseek(fd, -bsize, SEEK_CUR);
-               if (r < 0)
-                       goto out;
-               memcpy(hangover_buf, buf + solid, hangover);
+static int _priority;
+static int _memlock_count = 0;
 
-               r = write(fd, hangover_buf, bsize);
-               if(r < 0 || r != bsize) goto out;
-               free(hangover_buf_base);
+// return 1 if memory is locked
+int crypt_memlock_inc(struct crypt_device *ctx)
+{
+       if (!_memlock_count++) {
+               log_dbg(ctx, "Locking memory.");
+               if (mlockall(MCL_CURRENT | MCL_FUTURE) == -1) {
+                       log_dbg(ctx, "Cannot lock memory with mlockall.");
+                       _memlock_count--;
+                       return 0;
+               }
+               errno = 0;
+               if (((_priority = getpriority(PRIO_PROCESS, 0)) == -1) && errno)
+                       log_err(ctx, _("Cannot get process priority."));
+               else
+                       if (setpriority(PRIO_PROCESS, 0, DEFAULT_PROCESS_PRIORITY))
+                               log_dbg(ctx, "setpriority %d failed: %s",
+                                       DEFAULT_PROCESS_PRIORITY, strerror(errno));
        }
-       ret = count;
- out:
-       if (buf != orig_buf)
-               free(buf_base);
-       return ret;
+       return _memlock_count ? 1 : 0;
 }
 
-ssize_t read_blockwise(int fd, void *orig_buf, size_t count) {
-       void *hangover_buf, *hangover_buf_base;
-       void *buf, *buf_base = NULL;
-       int r, hangover, solid, bsize, alignment;
-       ssize_t ret = -1;
-
-       if ((bsize = sector_size(fd)) < 0)
-               return bsize;
-
-       hangover = count % bsize;
-       solid = count - hangover;
-       alignment = get_alignment(fd);
-
-       if ((long)orig_buf & (alignment - 1)) {
-               buf = aligned_malloc(&buf_base, count, alignment);
-               if (!buf)
-                       goto out;
-       } else
-               buf = orig_buf;
-
-       r = read(fd, buf, solid);
-       if(r < 0 || r != solid)
-               goto out;
-
-       if (hangover) {
-               hangover_buf = aligned_malloc(&hangover_buf_base, bsize, alignment);
-               if (!hangover_buf)
-                       goto out;
-               r = read(fd, hangover_buf, bsize);
-               if (r <  0 || r != bsize)
-                       goto out;
-
-               memcpy(buf + solid, hangover_buf, hangover);
-               free(hangover_buf_base);
-       }
-       ret = count;
- out:
-       if (buf != orig_buf) {
-               memcpy(orig_buf, buf, count);
-               free(buf_base);
+int crypt_memlock_dec(struct crypt_device *ctx)
+{
+       if (_memlock_count && (!--_memlock_count)) {
+               log_dbg(ctx, "Unlocking memory.");
+               if (munlockall() == -1)
+                       log_err(ctx, _("Cannot unlock memory."));
+               if (setpriority(PRIO_PROCESS, 0, _priority))
+                       log_dbg(ctx, "setpriority %d failed: %s", _priority, strerror(errno));
        }
-       return ret;
+       return _memlock_count ? 1 : 0;
 }
 
-/* 
- * Combines llseek with blockwise write. write_blockwise can already deal with short writes
- * but we also need a function to deal with short writes at the start. But this information
- * is implicitly included in the read/write offset, which can not be set to non-aligned 
- * boundaries. Hence, we combine llseek with write.
+/* Keyfile processing */
+
+/*
+ * A simple call to lseek(3) might not be possible for some inputs (e.g.
+ * reading from a pipe), so this function instead reads of up to BUFSIZ bytes
+ * at a time until the specified number of bytes. It returns -1 on read error
+ * or when it reaches EOF before the requested number of bytes have been
+ * discarded.
  */
+static int keyfile_seek(int fd, uint64_t bytes)
+{
+       char tmp[BUFSIZ];
+       size_t next_read;
+       ssize_t bytes_r;
+       off64_t r;
 
-ssize_t write_lseek_blockwise(int fd, const char *buf, size_t count, off_t offset) {
-       int bsize = sector_size(fd);
-       const char *orig_buf = buf;
-       char frontPadBuf[bsize];
-       int frontHang = offset % bsize;
-       int r;
-       int innerCount = count < bsize ? count : bsize;
+       r = lseek64(fd, bytes, SEEK_CUR);
+       if (r > 0)
+               return 0;
+       if (r < 0 && errno != ESPIPE)
+               return -1;
 
-       if (bsize < 0)
-               return bsize;
+       while (bytes > 0) {
+               /* figure out how much to read */
+               next_read = bytes > sizeof(tmp) ? sizeof(tmp) : (size_t)bytes;
 
-       lseek(fd, offset - frontHang, SEEK_SET);
-       if(offset % bsize) {
-               r = read(fd,frontPadBuf,bsize);
-               if(r < 0) return -1;
+               bytes_r = read(fd, tmp, next_read);
+               if (bytes_r < 0) {
+                       if (errno == EINTR)
+                               continue;
 
-               memcpy(frontPadBuf+frontHang, buf, innerCount);
+                       crypt_safe_memzero(tmp, sizeof(tmp));
+                       /* read error */
+                       return -1;
+               }
 
-               lseek(fd, offset - frontHang, SEEK_SET);
-               r = write(fd,frontPadBuf,bsize);
-               if(r < 0) return -1;
+               if (bytes_r == 0)
+                       /* EOF */
+                       break;
 
-               buf += innerCount;
-               count -= innerCount;
+               bytes -= bytes_r;
        }
-       if(count <= 0) return buf - orig_buf;
 
-       return write_blockwise(fd, buf, count) + innerCount;
+       crypt_safe_memzero(tmp, sizeof(tmp));
+       return bytes == 0 ? 0 : -1;
 }
 
-int device_ready(struct crypt_device *cd, const char *device, int mode)
+int crypt_keyfile_device_read(struct crypt_device *cd,  const char *keyfile,
+                             char **key, size_t *key_size_read,
+                             uint64_t keyfile_offset, size_t key_size,
+                             uint32_t flags)
 {
-       int devfd, r = 1;
-       ssize_t s;
+       int fd, regular_file, char_to_read = 0, char_read = 0, unlimited_read = 0;
+       int r = -EINVAL, newline;
+       char *pass = NULL;
+       size_t buflen, i;
+       uint64_t file_read_size;
        struct stat st;
-       char buf[512];
 
-       if(stat(device, &st) < 0) {
-               log_err(cd, _("Device %s doesn't exist or access denied.\n"), device);
-               return 0;
-       }
+       if (!key || !key_size_read)
+               return -EINVAL;
 
-       log_dbg("Trying to open and read device %s.", device);
-       devfd = open(device, mode | O_DIRECT | O_SYNC);
-       if(devfd < 0) {
-               log_err(cd, _("Cannot open device %s for %s%s access.\n"), device,
-                       (mode & O_EXCL) ? _("exclusive ") : "",
-                       (mode & O_RDWR) ? _("writable") : _("read-only"));
-               return 0;
-       }
+       *key = NULL;
+       *key_size_read = 0;
 
-        /* Try to read first sector */
-       s = read_blockwise(devfd, buf, sizeof(buf));
-       if (s < 0 || s != sizeof(buf)) {
-               log_err(cd, _("Cannot read device %s.\n"), device);
-               r = 0;
+       fd = keyfile ? open(keyfile, O_RDONLY) : STDIN_FILENO;
+       if (fd < 0) {
+               log_err(cd, _("Failed to open key file."));
+               return -EINVAL;
        }
 
-       memset(buf, 0, sizeof(buf));
-       close(devfd);
+       if (isatty(fd)) {
+               log_err(cd, _("Cannot read keyfile from a terminal."));
+               r = -EINVAL;
+               goto out_err;
+       }
 
-       return r;
-}
+       /* If not requested otherwise, we limit input to prevent memory exhaustion */
+       if (key_size == 0) {
+               key_size = DEFAULT_KEYFILE_SIZE_MAXKB * 1024 + 1;
+               unlimited_read = 1;
+               /* use 4k for buffer (page divisor but avoid huge pages) */
+               buflen = 4096 - sizeof(size_t); // sizeof(struct safe_allocation);
+       } else
+               buflen = key_size;
 
-int get_device_infos(const char *device, struct device_infos *infos, struct crypt_device *cd)
-{
-       uint64_t size;
-       unsigned long size_small;
-       int readonly = 0;
-       int ret = -1;
-       int fd;
-
-       /* Try to open read-write to check whether it is a read-only device */
-       fd = open(device, O_RDWR);
-       if (fd < 0) {
-               if (errno == EROFS) {
-                       readonly = 1;
-                       fd = open(device, O_RDONLY);
+       regular_file = 0;
+       if (keyfile) {
+               if (stat(keyfile, &st) < 0) {
+                       log_err(cd, _("Failed to stat key file."));
+                       goto out_err;
+               }
+               if (S_ISREG(st.st_mode)) {
+                       regular_file = 1;
+                       file_read_size = (uint64_t)st.st_size;
+
+                       if (keyfile_offset > file_read_size) {
+                               log_err(cd, _("Cannot seek to requested keyfile offset."));
+                               goto out_err;
+                       }
+                       file_read_size -= keyfile_offset;
+
+                       /* known keyfile size, alloc it in one step */
+                       if (file_read_size >= (uint64_t)key_size)
+                               buflen = key_size;
+                       else if (file_read_size)
+                               buflen = file_read_size;
                }
-       } else {
-               close(fd);
-               fd = open(device, O_RDONLY);
-       }
-       if (fd < 0) {
-               log_err(cd, _("Cannot open device: %s\n"), device);
-               return -1;
        }
 
-#ifdef BLKROGET
-       /* If the device can be opened read-write, i.e. readonly is still 0, then
-        * check whether BKROGET says that it is read-only. E.g. read-only loop
-        * devices may be openend read-write but are read-only according to BLKROGET
-        */
-       if (readonly == 0 && ioctl(fd, BLKROGET, &readonly) < 0) {
-               log_err(cd, _("BLKROGET failed on device %s.\n"), device);
-               goto out;
-       }
-#else
-#error BLKROGET not available
-#endif
-
-#ifdef BLKGETSIZE64
-       if (ioctl(fd, BLKGETSIZE64, &size) >= 0) {
-               size >>= SECTOR_SHIFT;
-               ret = 0;
-               goto out;
+       pass = crypt_safe_alloc(buflen);
+       if (!pass) {
+               log_err(cd, _("Out of memory while reading passphrase."));
+               goto out_err;
        }
-#endif
 
-#ifdef BLKGETSIZE
-       if (ioctl(fd, BLKGETSIZE, &size_small) >= 0) {
-               size = (uint64_t)size_small;
-               ret = 0;
-               goto out;
+       /* Discard keyfile_offset bytes on input */
+       if (keyfile_offset && keyfile_seek(fd, keyfile_offset) < 0) {
+               log_err(cd, _("Cannot seek to requested keyfile offset."));
+               goto out_err;
        }
-#else
-#      error Need at least the BLKGETSIZE ioctl!
-#endif
-
-       log_err(cd, _("BLKGETSIZE failed on device %s.\n"), device);
-out:
-       if (ret == 0) {
-               infos->size = size;
-               infos->readonly = readonly;
-       }
-       close(fd);
-       return ret;
-}
 
-int wipe_device_header(const char *device, int sectors)
-{
-       char *buffer;
-       int size = sectors * SECTOR_SIZE;
-       int r = -1;
-       int devfd;
+       for (i = 0, newline = 0; i < key_size; i += char_read) {
+               if (i == buflen) {
+                       buflen += 4096;
+                       pass = crypt_safe_realloc(pass, buflen);
+                       if (!pass) {
+                               log_err(cd, _("Out of memory while reading passphrase."));
+                               r = -ENOMEM;
+                               goto out_err;
+                       }
+               }
 
-       devfd = open(device, O_RDWR | O_DIRECT | O_SYNC);
-       if(devfd == -1)
-               return -EINVAL;
+               if (flags & CRYPT_KEYFILE_STOP_EOL) {
+                       /* If we should stop on newline, we must read the input
+                        * one character at the time. Otherwise we might end up
+                        * having read some bytes after the newline, which we
+                        * promised not to do.
+                        */
+                       char_to_read = 1;
+               } else {
+                       /* char_to_read = min(key_size - i, buflen - i) */
+                       char_to_read = key_size < buflen ?
+                               key_size - i : buflen - i;
+               }
+               char_read = read_buffer(fd, &pass[i], char_to_read);
+               if (char_read < 0) {
+                       log_err(cd, _("Error reading passphrase."));
+                       r = -EPIPE;
+                       goto out_err;
+               }
 
-       buffer = malloc(size);
-       if (!buffer) {
-               close(devfd);
-               return -ENOMEM;
+               if (char_read == 0)
+                       break;
+               /* Stop on newline only if not requested read from keyfile */
+               if ((flags & CRYPT_KEYFILE_STOP_EOL) && pass[i] == '\n') {
+                       newline = 1;
+                       pass[i] = '\0';
+                       break;
+               }
        }
-       memset(buffer, 0, size);
-
-       r = write_blockwise(devfd, buffer, size) < size ? -EIO : 0;
 
-       free(buffer);
-       close(devfd);
+       /* Fail if piped input dies reading nothing */
+       if (!i && !regular_file && !newline) {
+               log_err(cd, _("Nothing to read on input."));
+               r = -EPIPE;
+               goto out_err;
+       }
 
-       return r;
-}
+       /* Fail if we exceeded internal default (no specified size) */
+       if (unlimited_read && i == key_size) {
+               log_err(cd, _("Maximum keyfile size exceeded."));
+               goto out_err;
+       }
 
-/* MEMLOCK */
-#define DEFAULT_PROCESS_PRIORITY -18
+       if (!unlimited_read && i != key_size) {
+               log_err(cd, _("Cannot read requested amount of data."));
+               goto out_err;
+       }
 
-static int _priority;
-static int _memlock_count = 0;
+       *key = pass;
+       *key_size_read = i;
+       r = 0;
+out_err:
+       if (fd != STDIN_FILENO)
+               close(fd);
 
-// return 1 if memory is locked
-int crypt_memlock_inc(struct crypt_device *ctx)
-{
-       if (!_memlock_count++) {
-               log_dbg("Locking memory.");
-               if (mlockall(MCL_CURRENT | MCL_FUTURE)) {
-                       log_err(ctx, _("WARNING!!! Possibly insecure memory. Are you root?\n"));
-                       _memlock_count--;
-                       return 0;
-               }
-               errno = 0;
-               if (((_priority = getpriority(PRIO_PROCESS, 0)) == -1) && errno)
-                       log_err(ctx, _("Cannot get process priority.\n"));
-               else
-                       if (setpriority(PRIO_PROCESS, 0, DEFAULT_PROCESS_PRIORITY))
-                               log_err(ctx, _("setpriority %u failed: %s"),
-                                       DEFAULT_PROCESS_PRIORITY, strerror(errno));
-       }
-       return _memlock_count ? 1 : 0;
+       if (r)
+               crypt_safe_free(pass);
+       return r;
 }
 
-int crypt_memlock_dec(struct crypt_device *ctx)
+int crypt_keyfile_read(struct crypt_device *cd,  const char *keyfile,
+                      char **key, size_t *key_size_read,
+                      size_t keyfile_offset, size_t keyfile_size_max,
+                      uint32_t flags)
 {
-       if (_memlock_count && (!--_memlock_count)) {
-               log_dbg("Unlocking memory.");
-               if (munlockall())
-                       log_err(ctx, _("Cannot unlock memory."));
-               if (setpriority(PRIO_PROCESS, 0, _priority))
-                       log_err(ctx, _("setpriority %u failed: %s"), _priority, strerror(errno));
-       }
-       return _memlock_count ? 1 : 0;
+       return crypt_keyfile_device_read(cd, keyfile, key, key_size_read,
+                                        keyfile_offset, keyfile_size_max, flags);
 }
 
-/* DEVICE TOPOLOGY */
+int kernel_version(uint64_t *kversion)
+{
+       struct utsname uts;
+       uint16_t maj, min, patch, rel;
+       int r = -EINVAL;
 
-/* block device topology ioctls, introduced in 2.6.32 */
-#ifndef BLKIOMIN
-#define BLKIOMIN    _IO(0x12,120)
-#define BLKIOOPT    _IO(0x12,121)
-#define BLKALIGNOFF _IO(0x12,122)
-#endif
+       if (uname(&uts) < 0)
+               return r;
 
-void get_topology_alignment(const char *device,
-                           unsigned long *required_alignment, /* bytes */
-                           unsigned long *alignment_offset,   /* bytes */
-                           unsigned long default_alignment)
-{
-       int dev_alignment_offset = 0;
-       unsigned int min_io_size = 0, opt_io_size = 0;
-       unsigned long temp_alignment = 0;
-       int fd;
-
-       *required_alignment = default_alignment;
-       *alignment_offset = 0;
-
-       fd = open(device, O_RDONLY);
-       if (fd == -1)
-               return;
-
-       /* minimum io size */
-       if (ioctl(fd, BLKIOMIN, &min_io_size) == -1) {
-               log_dbg("Topology info for %s not supported, using default offset %lu bytes.",
-                       device, default_alignment);
-               goto out;
+       if (sscanf(uts.release, "%" SCNu16  ".%" SCNu16 ".%" SCNu16 "-%" SCNu16,
+                  &maj, &min, &patch, &rel) == 4)
+               r = 0;
+       else if (sscanf(uts.release,  "%" SCNu16 ".%" SCNu16 ".%" SCNu16,
+                       &maj, &min, &patch) == 3) {
+               rel = 0;
+               r = 0;
        }
 
-       /* optimal io size */
-       if (ioctl(fd, BLKIOOPT, &opt_io_size) == -1)
-               opt_io_size = min_io_size;
+       if (!r)
+               *kversion = version(maj, min, patch, rel);
 
-       /* alignment offset, bogus -1 means misaligned/unknown */
-       if (ioctl(fd, BLKALIGNOFF, &dev_alignment_offset) == -1 || dev_alignment_offset < 0)
-               dev_alignment_offset = 0;
-       *alignment_offset = (unsigned long)dev_alignment_offset;
+       return r;
+}
 
-       temp_alignment = (unsigned long)min_io_size;
+bool crypt_string_in(const char *str, char **list, size_t list_size)
+{
+       size_t i;
 
-       if (temp_alignment < (unsigned long)opt_io_size)
-               temp_alignment = (unsigned long)opt_io_size;
+       for (i = 0; *list && i < list_size; i++, list++)
+               if (!strcmp(str, *list))
+                       return true;
 
-       /* If calculated alignment is multiple of default, keep default */
-       if (temp_alignment && (default_alignment % temp_alignment))
-               *required_alignment = temp_alignment;
+       return false;
+}
 
-       log_dbg("Topology: IO (%u/%u), offset = %lu; Required alignment is %lu bytes.",
-               min_io_size, opt_io_size, *alignment_offset, *required_alignment);
-out:
-       (void)close(fd);
+/* compare two strings (allows NULL values) */
+int crypt_strcmp(const char *a, const char *b)
+{
+       if (!a && !b)
+               return 0;
+       else if (!a || !b)
+               return 1;
+       return strcmp(a, b);
 }