2bc722a97e
The functions fnmatch(), getopt(), getentropy() and others are grouped into the standard Option Group POSIX_C_LIB_EXT. The getentropy() function is currently in-draft for Issue 8 as of 2021. https://www.opengroup.org/austin/docs/austin_1110.pdf Not surprisingly, the POSIX_C_LIB_EXT Option Group also includes the highly debated strnlen() function. Moving that function will be deferred until later. Signed-off-by: Chris Friedt <cfriedt@tenstorrent.com>
45 lines
831 B
C
45 lines
831 B
C
/*
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* Copyright (c) 2024 Google LLC
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#include <errno.h>
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#include <zephyr/drivers/entropy.h>
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#include <zephyr/kernel.h>
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#include <zephyr/posix/unistd.h>
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#define ENTROPY_NODE DEVICE_DT_GET_OR_NULL(DT_CHOSEN(zephyr_entropy))
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int getentropy(void *buffer, size_t length)
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{
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const struct device *const entropy = ENTROPY_NODE;
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if (!buffer) {
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errno = EFAULT;
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return -1;
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}
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if (length > 256) {
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errno = EIO;
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return -1;
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}
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if (entropy == NULL || !device_is_ready(entropy)) {
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errno = EIO;
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return -1;
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}
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/*
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* getentropy() uses size_t to represent buffer size, but Zephyr uses
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* uint16_t. The length check above allows us to safely cast without
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* overflow.
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*/
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if (entropy_get_entropy(entropy, buffer, (uint16_t)length)) {
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errno = EIO;
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return -1;
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}
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return 0;
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}
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