1*0e552da7Schristos /* Copyright libuv contributors. All rights reserved.
2*0e552da7Schristos *
3*0e552da7Schristos * Permission is hereby granted, free of charge, to any person obtaining a copy
4*0e552da7Schristos * of this software and associated documentation files (the "Software"), to
5*0e552da7Schristos * deal in the Software without restriction, including without limitation the
6*0e552da7Schristos * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
7*0e552da7Schristos * sell copies of the Software, and to permit persons to whom the Software is
8*0e552da7Schristos * furnished to do so, subject to the following conditions:
9*0e552da7Schristos *
10*0e552da7Schristos * The above copyright notice and this permission notice shall be included in
11*0e552da7Schristos * all copies or substantial portions of the Software.
12*0e552da7Schristos *
13*0e552da7Schristos * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
14*0e552da7Schristos * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
15*0e552da7Schristos * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
16*0e552da7Schristos * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
17*0e552da7Schristos * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
18*0e552da7Schristos * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
19*0e552da7Schristos * IN THE SOFTWARE.
20*0e552da7Schristos */
21*0e552da7Schristos
22*0e552da7Schristos #include "uv.h"
23*0e552da7Schristos #include "internal.h"
24*0e552da7Schristos
25*0e552da7Schristos #include <sys/stat.h>
26*0e552da7Schristos #include <unistd.h>
27*0e552da7Schristos
28*0e552da7Schristos static uv_once_t once = UV_ONCE_INIT;
29*0e552da7Schristos static int status;
30*0e552da7Schristos
31*0e552da7Schristos
uv__random_readpath(const char * path,void * buf,size_t buflen)32*0e552da7Schristos int uv__random_readpath(const char* path, void* buf, size_t buflen) {
33*0e552da7Schristos struct stat s;
34*0e552da7Schristos size_t pos;
35*0e552da7Schristos ssize_t n;
36*0e552da7Schristos int fd;
37*0e552da7Schristos
38*0e552da7Schristos fd = uv__open_cloexec(path, O_RDONLY);
39*0e552da7Schristos
40*0e552da7Schristos if (fd < 0)
41*0e552da7Schristos return fd;
42*0e552da7Schristos
43*0e552da7Schristos if (fstat(fd, &s)) {
44*0e552da7Schristos uv__close(fd);
45*0e552da7Schristos return UV__ERR(errno);
46*0e552da7Schristos }
47*0e552da7Schristos
48*0e552da7Schristos if (!S_ISCHR(s.st_mode)) {
49*0e552da7Schristos uv__close(fd);
50*0e552da7Schristos return UV_EIO;
51*0e552da7Schristos }
52*0e552da7Schristos
53*0e552da7Schristos for (pos = 0; pos != buflen; pos += n) {
54*0e552da7Schristos do
55*0e552da7Schristos n = read(fd, (char*) buf + pos, buflen - pos);
56*0e552da7Schristos while (n == -1 && errno == EINTR);
57*0e552da7Schristos
58*0e552da7Schristos if (n == -1) {
59*0e552da7Schristos uv__close(fd);
60*0e552da7Schristos return UV__ERR(errno);
61*0e552da7Schristos }
62*0e552da7Schristos
63*0e552da7Schristos if (n == 0) {
64*0e552da7Schristos uv__close(fd);
65*0e552da7Schristos return UV_EIO;
66*0e552da7Schristos }
67*0e552da7Schristos }
68*0e552da7Schristos
69*0e552da7Schristos uv__close(fd);
70*0e552da7Schristos return 0;
71*0e552da7Schristos }
72*0e552da7Schristos
73*0e552da7Schristos
uv__random_devurandom_init(void)74*0e552da7Schristos static void uv__random_devurandom_init(void) {
75*0e552da7Schristos char c;
76*0e552da7Schristos
77*0e552da7Schristos /* Linux's random(4) man page suggests applications should read at least
78*0e552da7Schristos * once from /dev/random before switching to /dev/urandom in order to seed
79*0e552da7Schristos * the system RNG. Reads from /dev/random can of course block indefinitely
80*0e552da7Schristos * until entropy is available but that's the point.
81*0e552da7Schristos */
82*0e552da7Schristos status = uv__random_readpath("/dev/random", &c, 1);
83*0e552da7Schristos }
84*0e552da7Schristos
85*0e552da7Schristos
uv__random_devurandom(void * buf,size_t buflen)86*0e552da7Schristos int uv__random_devurandom(void* buf, size_t buflen) {
87*0e552da7Schristos uv_once(&once, uv__random_devurandom_init);
88*0e552da7Schristos
89*0e552da7Schristos if (status != 0)
90*0e552da7Schristos return status;
91*0e552da7Schristos
92*0e552da7Schristos return uv__random_readpath("/dev/urandom", buf, buflen);
93*0e552da7Schristos }
94