*/
/*
- * Copyright (C) 2012, 2013, 2014 Eric Biggers
+ * Copyright (C) 2012-2016 Eric Biggers
*
* This file is free software; you can redistribute it and/or modify it under
* the terms of the GNU Lesser General Public License as published by the Free
# include "config.h"
#endif
+#include <errno.h>
+#include <fcntl.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>
# include <sys/types.h>
# include <sys/sysctl.h>
#endif
+#ifdef HAVE_SYS_SYSCALL_H
+# include <sys/syscall.h>
+#endif
#include <unistd.h>
#include "wimlib.h"
wimlib_calloc(size_t nmemb, size_t size)
{
size_t total_size = nmemb * size;
- void *p = MALLOC(total_size);
+ void *p;
+
+ if (size != 0 && nmemb > SIZE_MAX / size) {
+ errno = ENOMEM;
+ return NULL;
+ }
+
+ p = MALLOC(total_size);
if (p)
p = memset(p, 0, total_size);
return p;
void *
wimlib_aligned_malloc(size_t size, size_t alignment)
{
- wimlib_assert(alignment != 0 && is_power_of_2(alignment) &&
- alignment <= 4096);
-
- const uintptr_t mask = alignment - 1;
- char *ptr = NULL;
- char *raw_ptr;
-
- raw_ptr = MALLOC(mask + sizeof(size_t) + size);
- if (raw_ptr) {
- ptr = (char *)raw_ptr + sizeof(size_t);
- ptr = (void *)(((uintptr_t)ptr + mask) & ~mask);
- *((size_t *)ptr - 1) = ptr - raw_ptr;
+ wimlib_assert(is_power_of_2(alignment));
+
+ void *ptr = MALLOC(sizeof(void *) + alignment - 1 + size);
+ if (ptr) {
+ void *orig_ptr = ptr;
+ ptr = (void *)ALIGN((uintptr_t)ptr + sizeof(void *), alignment);
+ ((void **)ptr)[-1] = orig_ptr;
}
return ptr;
}
wimlib_aligned_free(void *ptr)
{
if (ptr)
- FREE((char *)ptr - *((size_t *)ptr - 1));
+ FREE(((void **)ptr)[-1]);
}
void *
}
#endif
-static bool seeded = false;
+/**************************
+ * Random number generation
+ **************************/
-static void
-seed_random(void)
+#ifndef __WIN32__
+/*
+ * Generate @n cryptographically secure random bytes (thread-safe)
+ *
+ * This is the UNIX version. It uses the Linux getrandom() system call if
+ * available; otherwise, it falls back to reading from /dev/urandom.
+ */
+void
+get_random_bytes(void *p, size_t n)
{
- srand(now_as_wim_timestamp());
- seeded = true;
+ if (n == 0)
+ return;
+#ifdef HAVE_NR_GETRANDOM
+ static bool getrandom_unavailable;
+
+ if (getrandom_unavailable)
+ goto try_dev_urandom;
+ do {
+ int res = syscall(__NR_getrandom, p, n, 0);
+ if (unlikely(res < 0)) {
+ if (errno == ENOSYS) {
+ getrandom_unavailable = true;
+ goto try_dev_urandom;
+ }
+ if (errno == EINTR)
+ continue;
+ ERROR_WITH_ERRNO("getrandom() failed");
+ wimlib_assert(0);
+ res = 0;
+ }
+ p += res;
+ n -= res;
+ } while (n != 0);
+ return;
+
+try_dev_urandom:
+ ;
+#endif /* HAVE_NR_GETRANDOM */
+ int fd = open("/dev/urandom", O_RDONLY);
+ if (fd < 0) {
+ ERROR_WITH_ERRNO("Unable to open /dev/urandom");
+ wimlib_assert(0);
+ }
+ do {
+ int res = read(fd, p, min(n, INT_MAX));
+ if (unlikely(res < 0)) {
+ if (errno == EINTR)
+ continue;
+ ERROR_WITH_ERRNO("Error reading from /dev/urandom");
+ wimlib_assert(0);
+ res = 0;
+ }
+ p += res;
+ n -= res;
+ } while (n != 0);
+ close(fd);
}
+#endif /* !__WIN32__ */
-/* Fills @n characters pointed to by @p with random alphanumeric characters. */
+/*
+ * Generate @n cryptographically secure random alphanumeric characters
+ * (thread-safe)
+ *
+ * This is implemented on top of get_random_bytes(). For efficiency the calls
+ * to get_random_bytes() are batched.
+ */
void
-randomize_char_array_with_alnum(tchar *p, size_t n)
+get_random_alnum_chars(tchar *p, size_t n)
{
- if (!seeded)
- seed_random();
- while (n--) {
- int r = rand() % 62;
- if (r < 26)
- *p++ = r + 'a';
- else if (r < 52)
- *p++ = r - 26 + 'A';
+ u32 r[64];
+ int r_idx = 0;
+ int r_end = 0;
+
+ for (; n != 0; p++, n--) {
+ tchar x;
+
+ if (r_idx >= r_end) {
+ r_idx = 0;
+ r_end = min(n, ARRAY_LEN(r));
+ get_random_bytes(r, r_end * sizeof(r[0]));
+ }
+
+ STATIC_ASSERT(sizeof(r[0]) == sizeof(u32));
+ while (unlikely(r[r_idx] >= UINT32_MAX - (UINT32_MAX % 62)))
+ get_random_bytes(&r[r_idx], sizeof(r[0]));
+
+ x = r[r_idx++] % 62;
+
+ if (x < 26)
+ *p = 'a' + x;
+ else if (x < 52)
+ *p = 'A' + x - 26;
else
- *p++ = r - 52 + '0';
+ *p = '0' + x - 52;
}
}
-/* Fills @n bytes pointer to by @p with random numbers. */
-void
-randomize_byte_array(u8 *p, size_t n)
-{
- if (!seeded)
- seed_random();
- while (n--)
- *p++ = rand();
-}
+/************************
+ * System information
+ ************************/
#ifndef __WIN32__
unsigned
git://wimlib.net / wimlib / blobdiff