summaryrefslogtreecommitdiff
path: root/src/shared/util.c
diff options
context:
space:
mode:
authorRonny Chevalier <chevalier.ronny@gmail.com>2015-04-10 22:27:10 +0200
committerRonny Chevalier <chevalier.ronny@gmail.com>2015-04-11 00:11:13 +0200
commit3df3e884ae1237ef0d4d23b0e80f4ffda95ac135 (patch)
tree630cb996d0cf23429633e4900826aac56d9271ad /src/shared/util.c
parent0b452006de98294d1690f045f6ea2f7f6630ec3b (diff)
shared: add random-util.[ch]
Diffstat (limited to 'src/shared/util.c')
-rw-r--r--src/shared/util.c96
1 files changed, 1 insertions, 95 deletions
diff --git a/src/shared/util.c b/src/shared/util.c
index d4753f1ee8..e4c4dd92f1 100644
--- a/src/shared/util.c
+++ b/src/shared/util.c
@@ -94,6 +94,7 @@
#include "sparse-endian.h"
#include "formats-util.h"
#include "process-util.h"
+#include "random-util.h"
/* Put this test here for a lack of better place */
assert_cc(EAGAIN == EWOULDBLOCK);
@@ -2387,101 +2388,6 @@ char* dirname_malloc(const char *path) {
return dir;
}
-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 or 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;
-
- x = 0;
-
-#ifdef HAVE_SYS_AUXV_H
- /* The kernel provides us with a bit 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)
- x ^= *(unsigned*) auxv;
-#endif
-
- 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();
-}
-
void rename_process(const char name[8]) {
assert(name);