1 /* 2 __ __ _ 3 ___\ \/ /_ __ __ _| |_ 4 / _ \\ /| '_ \ / _` | __| 5 | __// \| |_) | (_| | |_ 6 \___/_/\_\ .__/ \__,_|\__| 7 |_| XML parser 8 9 Copyright (c) 2017-2026 Sebastian Pipping <sebastian@pipping.org> 10 Copyright (c) 2017 Chanho Park <chanho61.park@samsung.com> 11 Copyright (c) 2022 Sean McBride <sean@rogue-research.com> 12 Copyright (c) 2026 Matthew Fernandez <matthew.fernandez@gmail.com> 13 Licensed under the MIT license: 14 15 Permission is hereby granted, free of charge, to any person obtaining 16 a copy of this software and associated documentation files (the 17 "Software"), to deal in the Software without restriction, including 18 without limitation the rights to use, copy, modify, merge, publish, 19 distribute, sublicense, and/or sell copies of the Software, and to permit 20 persons to whom the Software is furnished to do so, subject to the 21 following conditions: 22 23 The above copyright notice and this permission notice shall be included 24 in all copies or substantial portions of the Software. 25 26 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 27 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 28 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN 29 NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, 30 DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR 31 OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE 32 USE OR OTHER DEALINGS IN THE SOFTWARE. 33 */ 34 35 #include "random_getrandom.h" 36 37 #include "expat_config.h" // for HAVE_GETRANDOM, HAVE_SYSCALL_GETRANDOM 38 39 #if defined(HAVE_GETRANDOM) 40 # include <sys/random.h> /* getrandom */ 41 #endif 42 43 #if defined(HAVE_SYSCALL_GETRANDOM) 44 # if ! defined(_GNU_SOURCE) 45 # define _GNU_SOURCE 1 /* syscall prototype */ 46 # endif 47 # include <unistd.h> /* syscall */ 48 # include <sys/syscall.h> /* SYS_getrandom */ 49 #endif // defined(HAVE_SYSCALL_GETRANDOM) 50 51 #if ! defined(GRND_NONBLOCK) 52 # define GRND_NONBLOCK 0x0001 53 #endif /* defined(GRND_NONBLOCK) */ 54 55 #include <assert.h> 56 #include <errno.h> 57 #include <limits.h> // for INT_MAX 58 59 /* Obtain entropy on Linux 3.17+ */ 60 bool 61 writeRandomBytes_getrandom_nonblock(void *target, size_t count) { 62 int success = false; /* full count bytes written? */ 63 size_t bytesWrittenTotal = 0; 64 const unsigned int getrandomFlags = GRND_NONBLOCK; 65 66 do { 67 void *const currentTarget = (void *)((char *)target + bytesWrittenTotal); 68 const size_t bytesToWrite = count - bytesWrittenTotal; 69 70 assert(bytesToWrite <= INT_MAX); 71 72 errno = 0; 73 74 const int bytesWrittenMore = 75 #if defined(HAVE_GETRANDOM) 76 (int)getrandom(currentTarget, bytesToWrite, getrandomFlags); 77 #else 78 (int)syscall(SYS_getrandom, currentTarget, bytesToWrite, 79 getrandomFlags); 80 #endif 81 82 if (bytesWrittenMore > 0) { 83 bytesWrittenTotal += bytesWrittenMore; 84 if (bytesWrittenTotal >= count) 85 success = true; 86 } 87 } while (! success && (errno == EINTR)); 88 89 return success; 90 } 91