| /* 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 <errno.h> |
| #include <string.h> |
| |
| #include <syscall.h> |
| #include <unistd.h> |
| |
| |
| struct uv__sysctl_args { |
| int* name; |
| int nlen; |
| void* oldval; |
| size_t* oldlenp; |
| void* newval; |
| size_t newlen; |
| unsigned long unused[4]; |
| }; |
| |
| |
| int uv__random_sysctl(void* buf, size_t buflen) { |
| static int name[] = {1 /*CTL_KERN*/, 40 /*KERN_RANDOM*/, 6 /*RANDOM_UUID*/}; |
| struct uv__sysctl_args args; |
| char uuid[16]; |
| char* p; |
| char* pe; |
| size_t n; |
| |
| p = buf; |
| pe = p + buflen; |
| |
| while (p < pe) { |
| memset(&args, 0, sizeof(args)); |
| |
| args.name = name; |
| args.nlen = ARRAY_SIZE(name); |
| args.oldval = uuid; |
| args.oldlenp = &n; |
| n = sizeof(uuid); |
| |
| /* Emits a deprecation warning with some kernels but that seems like |
| * an okay trade-off for the fallback of the fallback: this function is |
| * only called when neither getrandom(2) nor /dev/urandom are available. |
| * Fails with ENOSYS on kernels configured without CONFIG_SYSCTL_SYSCALL. |
| * At least arm64 never had a _sysctl system call and therefore doesn't |
| * have a SYS__sysctl define either. |
| */ |
| #ifdef SYS__sysctl |
| if (syscall(SYS__sysctl, &args) == -1) |
| return UV__ERR(errno); |
| #else |
| { |
| (void) &args; |
| return UV_ENOSYS; |
| } |
| #endif |
| |
| if (n != sizeof(uuid)) |
| return UV_EIO; /* Can't happen. */ |
| |
| /* uuid[] is now a type 4 UUID. Bytes 6 and 8 (counting from zero) contain |
| * 4 and 5 bits of entropy, respectively. For ease of use, we skip those |
| * and only use 14 of the 16 bytes. |
| */ |
| uuid[6] = uuid[14]; |
| uuid[8] = uuid[15]; |
| |
| n = pe - p; |
| if (n > 14) |
| n = 14; |
| |
| memcpy(p, uuid, n); |
| p += n; |
| } |
| |
| return 0; |
| } |