xref: /libuv/src/random.c (revision 7c491bde)
1 /* Copyright libuv contributors. All rights reserved.
2  *
3  * Permission is hereby granted, free of charge, to any person obtaining a copy
4  * of this software and associated documentation files (the "Software"), to
5  * deal in the Software without restriction, including without limitation the
6  * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
7  * sell copies of the Software, and to permit persons to whom the Software is
8  * furnished to do so, subject to the following conditions:
9  *
10  * The above copyright notice and this permission notice shall be included in
11  * all copies or substantial portions of the Software.
12  *
13  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
14  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
15  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
16  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
17  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
18  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
19  * IN THE SOFTWARE.
20  */
21 
22 #include "uv.h"
23 #include "uv-common.h"
24 
25 #ifdef _WIN32
26 #  include "win/internal.h"
27 #else
28 #  include "unix/internal.h"
29 #endif
30 
uv__random(void * buf,size_t buflen)31 static int uv__random(void* buf, size_t buflen) {
32   int rc;
33 
34 #if defined(__PASE__)
35   rc = uv__random_readpath("/dev/urandom", buf, buflen);
36 #elif defined(_AIX) || defined(__QNX__)
37   rc = uv__random_readpath("/dev/random", buf, buflen);
38 #elif defined(__APPLE__) || defined(__OpenBSD__) || \
39      (defined(__ANDROID_API__) && __ANDROID_API__ >= 28)
40   rc = uv__random_getentropy(buf, buflen);
41   if (rc == UV_ENOSYS)
42     rc = uv__random_devurandom(buf, buflen);
43 #elif defined(__NetBSD__)
44   rc = uv__random_sysctl(buf, buflen);
45 #elif defined(__FreeBSD__) || defined(__linux__)
46   rc = uv__random_getrandom(buf, buflen);
47   if (rc == UV_ENOSYS)
48     rc = uv__random_devurandom(buf, buflen);
49 # if defined(__linux__)
50   switch (rc) {
51     case UV_EACCES:
52     case UV_EIO:
53     case UV_ELOOP:
54     case UV_EMFILE:
55     case UV_ENFILE:
56     case UV_ENOENT:
57     case UV_EPERM:
58       rc = uv__random_sysctl(buf, buflen);
59       break;
60   }
61 # endif
62 #elif defined(_WIN32)
63   uv__once_init();
64   rc = uv__random_rtlgenrandom(buf, buflen);
65 #else
66   rc = uv__random_devurandom(buf, buflen);
67 #endif
68 
69   return rc;
70 }
71 
72 
uv__random_work(struct uv__work * w)73 static void uv__random_work(struct uv__work* w) {
74   uv_random_t* req;
75 
76   req = container_of(w, uv_random_t, work_req);
77   req->status = uv__random(req->buf, req->buflen);
78 }
79 
80 
uv__random_done(struct uv__work * w,int status)81 static void uv__random_done(struct uv__work* w, int status) {
82   uv_random_t* req;
83 
84   req = container_of(w, uv_random_t, work_req);
85   uv__req_unregister(req->loop);
86 
87   if (status == 0)
88     status = req->status;
89 
90   req->cb(req, status, req->buf, req->buflen);
91 }
92 
93 
uv_random(uv_loop_t * loop,uv_random_t * req,void * buf,size_t buflen,unsigned flags,uv_random_cb cb)94 int uv_random(uv_loop_t* loop,
95               uv_random_t* req,
96               void *buf,
97               size_t buflen,
98               unsigned flags,
99               uv_random_cb cb) {
100   if (buflen > 0x7FFFFFFFu)
101     return UV_E2BIG;
102 
103   if (flags != 0)
104     return UV_EINVAL;
105 
106   if (cb == NULL)
107     return uv__random(buf, buflen);
108 
109   uv__req_init(loop, req, UV_RANDOM);
110   req->loop = loop;
111   req->status = 0;
112   req->cb = cb;
113   req->buf = buf;
114   req->buflen = buflen;
115 
116   uv__work_submit(loop,
117                   &req->work_req,
118                   UV__WORK_CPU,
119                   uv__random_work,
120                   uv__random_done);
121 
122   return 0;
123 }
124