diff --git a/library/entropy_poll.c b/library/entropy_poll.c
new file mode 100644
index 0000000..794ee03
--- /dev/null
+++ b/library/entropy_poll.c
@@ -0,0 +1,229 @@
+/*
+ *  Platform-specific and custom entropy polling functions
+ *
+ *  Copyright The Mbed TLS Contributors
+ *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+ */
+
+#if defined(__linux__) || defined(__midipix__) && !defined(_GNU_SOURCE)
+/* Ensure that syscall() is available even when compiling with -std=c99 */
+#define _GNU_SOURCE
+#endif
+
+#include "common.h"
+
+#include <string.h>
+
+#if defined(MBEDTLS_ENTROPY_C)
+
+#include "mbedtls/entropy.h"
+#include "entropy_poll.h"
+#include "mbedtls/error.h"
+
+#if defined(MBEDTLS_TIMING_C)
+#include "mbedtls/timing.h"
+#endif
+#include "mbedtls/platform.h"
+
+#if !defined(MBEDTLS_NO_PLATFORM_ENTROPY)
+
+#if !defined(unix) && !defined(__unix__) && !defined(__unix) && \
+    !defined(__APPLE__) && !defined(_WIN32) && !defined(__QNXNTO__) && \
+    !defined(__HAIKU__) && !defined(__midipix__) && !defined(__MVS__)
+#error \
+    "Platform entropy sources only work on Unix and Windows, see MBEDTLS_NO_PLATFORM_ENTROPY in mbedtls_config.h"
+#endif
+
+#if defined(_WIN32) && !defined(EFIX64) && !defined(EFI32)
+
+#include <windows.h>
+#include <bcrypt.h>
+#include <intsafe.h>
+
+int mbedtls_platform_entropy_poll(void *data, unsigned char *output, size_t len,
+                                  size_t *olen)
+{
+    ((void) data);
+    *olen = 0;
+
+    /*
+     * BCryptGenRandom takes ULONG for size, which is smaller than size_t on
+     * 64-bit Windows platforms. Extract entropy in chunks of len (dependent
+     * on ULONG_MAX) size.
+     */
+    while (len != 0) {
+        unsigned long ulong_bytes =
+            (len > ULONG_MAX) ? ULONG_MAX : (unsigned long) len;
+
+        if (!BCRYPT_SUCCESS(BCryptGenRandom(NULL, output, ulong_bytes,
+                                            BCRYPT_USE_SYSTEM_PREFERRED_RNG))) {
+            return MBEDTLS_ERR_ENTROPY_SOURCE_FAILED;
+        }
+
+        *olen += ulong_bytes;
+        len -= ulong_bytes;
+    }
+
+    return 0;
+}
+#else /* _WIN32 && !EFIX64 && !EFI32 */
+
+/*
+ * Test for Linux getrandom() support.
+ * Since there is no wrapper in the libc yet, use the generic syscall wrapper
+ * available in GNU libc and compatible libc's (eg uClibc).
+ */
+#if ((defined(__linux__) && defined(__GLIBC__)) || defined(__midipix__))
+#include <unistd.h>
+#include <sys/syscall.h>
+#if defined(SYS_getrandom)
+#define HAVE_GETRANDOM
+#include <errno.h>
+
+static int getrandom_wrapper(void *buf, size_t buflen, unsigned int flags)
+{
+    /* MemSan cannot understand that the syscall writes to the buffer */
+#if defined(__has_feature)
+#if __has_feature(memory_sanitizer)
+    memset(buf, 0, buflen);
+#endif
+#endif
+    return (int) syscall(SYS_getrandom, buf, buflen, flags);
+}
+#endif /* SYS_getrandom */
+#endif /* __linux__ || __midipix__ */
+
+#if defined(__FreeBSD__) || defined(__DragonFly__)
+#include <sys/param.h>
+#if (defined(__FreeBSD__) && __FreeBSD_version >= 1200000) || \
+    (defined(__DragonFly__) && __DragonFly_version >= 500700)
+#include <errno.h>
+#include <sys/random.h>
+#define HAVE_GETRANDOM
+static int getrandom_wrapper(void *buf, size_t buflen, unsigned int flags)
+{
+    return (int) getrandom(buf, buflen, flags);
+}
+#endif /* (__FreeBSD__ && __FreeBSD_version >= 1200000) ||
+          (__DragonFly__ && __DragonFly_version >= 500700) */
+#endif /* __FreeBSD__ || __DragonFly__ */
+
+/*
+ * Some BSD systems provide KERN_ARND.
+ * This is equivalent to reading from /dev/urandom, only it doesn't require an
+ * open file descriptor, and provides up to 256 bytes per call (basically the
+ * same as getentropy(), but with a longer history).
+ *
+ * Documentation: https://netbsd.gw.com/cgi-bin/man-cgi?sysctl+7
+ */
+#if (defined(__FreeBSD__) || defined(__NetBSD__)) && !defined(HAVE_GETRANDOM)
+#include <sys/param.h>
+#include <sys/sysctl.h>
+#if defined(KERN_ARND)
+#define HAVE_SYSCTL_ARND
+
+static int sysctl_arnd_wrapper(unsigned char *buf, size_t buflen)
+{
+    int name[2];
+    size_t len;
+
+    name[0] = CTL_KERN;
+    name[1] = KERN_ARND;
+
+    while (buflen > 0) {
+        len = buflen > 256 ? 256 : buflen;
+        if (sysctl(name, 2, buf, &len, NULL, 0) == -1) {
+            return -1;
+        }
+        buflen -= len;
+        buf += len;
+    }
+    return 0;
+}
+#endif /* KERN_ARND */
+#endif /* __FreeBSD__ || __NetBSD__ */
+
+#include <stdio.h>
+
+int mbedtls_platform_entropy_poll(void *data,
+                                  unsigned char *output, size_t len, size_t *olen)
+{
+    FILE *file;
+    size_t read_len;
+    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
+    ((void) data);
+
+#if defined(HAVE_GETRANDOM)
+    ret = getrandom_wrapper(output, len, 0);
+    if (ret >= 0) {
+        *olen = (size_t) ret;
+        return 0;
+    } else if (errno != ENOSYS) {
+        return MBEDTLS_ERR_ENTROPY_SOURCE_FAILED;
+    }
+    /* Fall through if the system call isn't known. */
+#else
+    ((void) ret);
+#endif /* HAVE_GETRANDOM */
+
+#if defined(HAVE_SYSCTL_ARND)
+    ((void) file);
+    ((void) read_len);
+    if (sysctl_arnd_wrapper(output, len) == -1) {
+        return MBEDTLS_ERR_ENTROPY_SOURCE_FAILED;
+    }
+    *olen = len;
+    return 0;
+#else
+
+    *olen = 0;
+
+    file = fopen("/dev/urandom", "rb");
+    if (file == NULL) {
+        return MBEDTLS_ERR_ENTROPY_SOURCE_FAILED;
+    }
+
+    /* Ensure no stdio buffering of secrets, as such buffers cannot be wiped. */
+    mbedtls_setbuf(file, NULL);
+
+    read_len = fread(output, 1, len, file);
+    if (read_len != len) {
+        fclose(file);
+        return MBEDTLS_ERR_ENTROPY_SOURCE_FAILED;
+    }
+
+    fclose(file);
+    *olen = len;
+
+    return 0;
+#endif /* HAVE_SYSCTL_ARND */
+}
+#endif /* _WIN32 && !EFIX64 && !EFI32 */
+#endif /* !MBEDTLS_NO_PLATFORM_ENTROPY */
+
+#if defined(MBEDTLS_ENTROPY_NV_SEED)
+int mbedtls_nv_seed_poll(void *data,
+                         unsigned char *output, size_t len, size_t *olen)
+{
+    unsigned char buf[MBEDTLS_ENTROPY_BLOCK_SIZE];
+    size_t use_len = MBEDTLS_ENTROPY_BLOCK_SIZE;
+    ((void) data);
+
+    memset(buf, 0, MBEDTLS_ENTROPY_BLOCK_SIZE);
+
+    if (mbedtls_nv_seed_read(buf, MBEDTLS_ENTROPY_BLOCK_SIZE) < 0) {
+        return MBEDTLS_ERR_ENTROPY_SOURCE_FAILED;
+    }
+
+    if (len < use_len) {
+        use_len = len;
+    }
+
+    memcpy(output, buf, use_len);
+    *olen = use_len;
+
+    return 0;
+}
+#endif /* MBEDTLS_ENTROPY_NV_SEED */
+
+#endif /* MBEDTLS_ENTROPY_C */