89 lines
2.5 KiB
C
89 lines
2.5 KiB
C
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/* Copyright libuv contributors. All rights reserved.
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to
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* deal in the Software without restriction, including without limitation the
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* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
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* sell copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
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* IN THE SOFTWARE.
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*/
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#include "uv.h"
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#include "internal.h"
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#ifdef __linux__
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#include "linux-syscalls.h"
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#define uv__random_getrandom_init() 0
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#else /* !__linux__ */
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#include <stddef.h>
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#include <dlfcn.h>
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typedef ssize_t (*uv__getrandom_cb)(void *, size_t, unsigned);
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static uv__getrandom_cb uv__getrandom;
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static uv_once_t once = UV_ONCE_INIT;
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static void uv__random_getrandom_init_once(void) {
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uv__getrandom = (uv__getrandom_cb) dlsym(RTLD_DEFAULT, "getrandom");
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}
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static int uv__random_getrandom_init(void) {
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uv_once(&once, uv__random_getrandom_init_once);
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if (uv__getrandom == NULL)
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return UV_ENOSYS;
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return 0;
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}
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#endif /* !__linux__ */
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int uv__random_getrandom(void* buf, size_t buflen) {
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ssize_t n;
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size_t pos;
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int rc;
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rc = uv__random_getrandom_init();
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if (rc != 0)
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return rc;
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for (pos = 0; pos != buflen; pos += n) {
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do {
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n = buflen - pos;
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/* Most getrandom() implementations promise that reads <= 256 bytes
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* will always succeed and won't be interrupted by signals.
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* It's therefore useful to split it up in smaller reads because
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* one big read may, in theory, continuously fail with EINTR.
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*/
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if (n > 256)
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n = 256;
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n = uv__getrandom((char *) buf + pos, n, 0);
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} while (n == -1 && errno == EINTR);
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if (n == -1)
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return UV__ERR(errno);
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if (n == 0)
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return UV_EIO;
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}
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return 0;
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}
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