diff options
Diffstat (limited to 'fluent-bit/lib/wasm-micro-runtime-WAMR-1.2.2/core/iwasm/libraries/libc-wasi/sandboxed-system-primitives/src/random.c')
-rw-r--r-- | fluent-bit/lib/wasm-micro-runtime-WAMR-1.2.2/core/iwasm/libraries/libc-wasi/sandboxed-system-primitives/src/random.c | 98 |
1 files changed, 98 insertions, 0 deletions
diff --git a/fluent-bit/lib/wasm-micro-runtime-WAMR-1.2.2/core/iwasm/libraries/libc-wasi/sandboxed-system-primitives/src/random.c b/fluent-bit/lib/wasm-micro-runtime-WAMR-1.2.2/core/iwasm/libraries/libc-wasi/sandboxed-system-primitives/src/random.c new file mode 100644 index 000000000..01a1dab3a --- /dev/null +++ b/fluent-bit/lib/wasm-micro-runtime-WAMR-1.2.2/core/iwasm/libraries/libc-wasi/sandboxed-system-primitives/src/random.c @@ -0,0 +1,98 @@ +// Part of the Wasmtime Project, under the Apache License v2.0 with LLVM +// Exceptions. See +// https://github.com/bytecodealliance/wasmtime/blob/main/LICENSE for license +// information. +// +// Significant parts of this file are derived from cloudabi-utils. See +// https://github.com/bytecodealliance/wasmtime/blob/main/lib/wasi/sandboxed-system-primitives/src/LICENSE +// for license information. +// +// The upstream file contains the following copyright notice: +// +// Copyright (c) 2016 Nuxi, https://nuxi.nl/ + +#include "ssp_config.h" +#include "bh_platform.h" +#include "random.h" + +#if CONFIG_HAS_ARC4RANDOM_BUF + +void +random_buf(void *buf, size_t len) +{ + arc4random_buf(buf, len); +} + +#elif CONFIG_HAS_GETRANDOM + +#ifndef BH_PLATFORM_LINUX_SGX +#include <sys/random.h> +#endif + +void +random_buf(void *buf, size_t len) +{ + for (;;) { + ssize_t x = getrandom(buf, len, 0); + if (x < 0) { + if (errno == EINTR) + continue; + os_printf("getrandom failed: %s", strerror(errno)); + abort(); + } + if ((size_t)x == len) + return; + buf = (void *)((unsigned char *)buf + x); + len -= (size_t)x; + } +} + +#else + +static int urandom; + +static void +open_urandom(void) +{ + urandom = open("/dev/urandom", O_RDONLY); + if (urandom < 0) { + os_printf("Failed to open /dev/urandom\n"); + abort(); + } +} + +void +random_buf(void *buf, size_t len) +{ + static pthread_once_t open_once = PTHREAD_ONCE_INIT; + pthread_once(&open_once, open_urandom); + + if ((size_t)read(urandom, buf, len) != len) { + os_printf("Short read on /dev/urandom\n"); + abort(); + } +} + +#endif + +// Calculates a random number within the range [0, upper - 1] without +// any modulo bias. +// +// The function below repeatedly obtains a random number from +// arc4random() until it lies within the range [2^k % upper, 2^k). As +// this range has length k * upper, we can safely obtain a number +// without any modulo bias. +uintmax_t +random_uniform(uintmax_t upper) +{ + // Compute 2^k % upper + // == (2^k - upper) % upper + // == -upper % upper. + uintmax_t lower = -upper % upper; + for (;;) { + uintmax_t value; + random_buf(&value, sizeof(value)); + if (value >= lower) + return value % upper; + } +} |