53 lines
1.6 KiB
C
53 lines
1.6 KiB
C
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// Copyright 2018 Espressif Systems (Shanghai) PTE LTD
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#include <sys/random.h>
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#include <sys/param.h>
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#include <assert.h>
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#include <errno.h>
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#include <string.h>
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#include "esp_system.h"
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#include "esp_log.h"
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static const char *TAG = "RANDOM";
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ssize_t getrandom(void *buf, size_t buflen, unsigned int flags)
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{
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// Flags are ignored because:
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// - esp_random is non-blocking so it works for both blocking and non-blocking calls,
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// - don't have opportunity so set som other source of entropy.
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ESP_LOGD(TAG, "getrandom(buf=0x%x, buflen=%d, flags=%u)", (int) buf, buflen, flags);
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if (buf == NULL) {
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errno = EFAULT;
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ESP_LOGD(TAG, "getrandom returns -1 (EFAULT)");
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return -1;
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}
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uint8_t *dst = (uint8_t *) buf;
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ssize_t ret = 0;
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while (ret < buflen) {
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const uint32_t random = esp_random();
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const int needed = buflen - ret;
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const int copy_len = MIN(sizeof(random), needed);
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memcpy(dst + ret, &random, copy_len);
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ret += copy_len;
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}
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ESP_LOGD(TAG, "getrandom returns %d", ret);
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return ret;
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}
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