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Diffstat (limited to 'src/basic/random-util.c')
| -rw-r--r-- | src/basic/random-util.c | 133 |
1 files changed, 0 insertions, 133 deletions
diff --git a/src/basic/random-util.c b/src/basic/random-util.c deleted file mode 100644 index ad7b3eedf2..0000000000 --- a/src/basic/random-util.c +++ /dev/null @@ -1,133 +0,0 @@ -/*** - This file is part of systemd. - - Copyright 2010 Lennart Poettering - - systemd is free software; you can redistribute it and/or modify it - under the terms of the GNU Lesser General Public License as published by - the Free Software Foundation; either version 2.1 of the License, or - (at your option) any later version. - - systemd is distributed in the hope that it will be useful, but - WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public License - along with systemd; If not, see <http://www.gnu.org/licenses/>. -***/ - -#include <elf.h> -#include <errno.h> -#include <fcntl.h> -#include <stdbool.h> -#include <stdlib.h> -#include <sys/time.h> -#include <linux/random.h> -#include <stdint.h> - -#ifdef HAVE_SYS_AUXV_H -#include <sys/auxv.h> -#endif - -#include "fd-util.h" -#include "io-util.h" -#include "missing.h" -#include "random-util.h" -#include "time-util.h" - -int dev_urandom(void *p, size_t n) { - static int have_syscall = -1; - - _cleanup_close_ int fd = -1; - int r; - - /* Gathers some randomness from the kernel. This call will - * never block, and will always return some data from the - * kernel, regardless if the random pool is fully initialized - * or not. It thus makes no guarantee for the quality of the - * returned entropy, but is good enough for our usual usecases - * of seeding the hash functions for hashtable */ - - /* Use the getrandom() syscall unless we know we don't have - * it, or when the requested size is too large for it. */ - if (have_syscall != 0 || (size_t) (int) n != n) { - r = getrandom(p, n, GRND_NONBLOCK); - if (r == (int) n) { - have_syscall = true; - return 0; - } - - if (r < 0) { - if (errno == ENOSYS) - /* we lack the syscall, continue with - * reading from /dev/urandom */ - have_syscall = false; - else if (errno == EAGAIN) - /* not enough entropy for now. Let's - * remember to use the syscall the - * next time, again, but also read - * from /dev/urandom for now, which - * doesn't care about the current - * amount of entropy. */ - have_syscall = true; - else - return -errno; - } else - /* too short read? */ - return -ENODATA; - } - - fd = open("/dev/urandom", O_RDONLY|O_CLOEXEC|O_NOCTTY); - if (fd < 0) - return errno == ENOENT ? -ENOSYS : -errno; - - return loop_read_exact(fd, p, n, true); -} - -void initialize_srand(void) { - static bool srand_called = false; - unsigned x; -#ifdef HAVE_SYS_AUXV_H - void *auxv; -#endif - - if (srand_called) - return; - -#ifdef HAVE_SYS_AUXV_H - /* The kernel provides us with 16 bytes of entropy in auxv, so let's try to make use of that to seed the - * pseudo-random generator. It's better than nothing... */ - - auxv = (void*) getauxval(AT_RANDOM); - if (auxv) { - assert_cc(sizeof(x) < 16); - memcpy(&x, auxv, sizeof(x)); - } else -#endif - x = 0; - - - x ^= (unsigned) now(CLOCK_REALTIME); - x ^= (unsigned) gettid(); - - srand(x); - srand_called = true; -} - -void random_bytes(void *p, size_t n) { - uint8_t *q; - int r; - - r = dev_urandom(p, n); - if (r >= 0) - return; - - /* If some idiot made /dev/urandom unavailable to us, he'll - * get a PRNG instead. */ - - initialize_srand(); - - for (q = p; q < (uint8_t*) p + n; q ++) - *q = rand(); -} |