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/* Copyright libuv contributors. All rights reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
#include "uv.h"
#include "internal.h"
#include <sys/stat.h>
#include <unistd.h>
static uv_once_t once = UV_ONCE_INIT;
static int status;
int uv__random_readpath(const char* path, void* buf, size_t buflen) {
struct stat s;
size_t pos;
ssize_t n;
int fd;
fd = uv__open_cloexec(path, O_RDONLY);
if (fd == -1)
return UV__ERR(errno);
if (fstat(fd, &s)) {
uv__close(fd);
return UV__ERR(errno);
}
if (!S_ISCHR(s.st_mode)) {
uv__close(fd);
return UV_EIO;
}
for (pos = 0; pos != buflen; pos += n) {
do
n = read(fd, (char*) buf + pos, buflen - pos);
while (n == -1 && errno == EINTR);
if (n == -1) {
uv__close(fd);
return UV__ERR(errno);
}
if (n == 0) {
uv__close(fd);
return UV_EIO;
}
}
uv__close(fd);
return 0;
}
static void uv__random_devurandom_init(void) {
char c;
/* Linux's random(4) man page suggests applications should read at least
* once from /dev/random before switching to /dev/urandom in order to seed
* the system RNG. Reads from /dev/random can of course block indefinitely
* until entropy is available but that's the point.
*/
status = uv__random_readpath("/dev/random", &c, 1);
}
int uv__random_devurandom(void* buf, size_t buflen) {
uv_once(&once, uv__random_devurandom_init);
if (status != 0)
return status;
return uv__random_readpath("/dev/urandom", buf, buflen);
}
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