mirrors/cosmopolitan
1
0
Fork 0
mirror of https://github.com/jart/cosmopolitan.git synced 2025-06-02 18:52:29 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 1

Make getentropy() faster

Browse source
This commit is contained in:
Justine Tunney 2024-10-10 18:24:23 -07:00
parent 17a85e4790
commit 000d6dbb0f
No known key found for this signature in database
GPG key ID: BE714B4575D6E328
2 changed files with 19 additions and 19 deletions
Download patch file Download diff file Expand all files Collapse all files

27
libc/stdio/getentropy.c
View file

@ -17,17 +17,16 @@
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/calls/blockcancel.internal.h"
#include "libc/calls/struct/sigset.internal.h"
#include "libc/calls/syscall_support-sysv.internal.h"
#include "libc/dce.h"
#include "libc/errno.h"
#include "libc/intrin/strace.h"
#include "libc/stdio/rand.h"
#include "libc/sysv/errfuns.h"
int sys_getentropy(void *, size_t) asm("sys_getrandom");
/**
* Returns random seeding bytes, the XNU/OpenBSD way.
* Returns random seeding bytes, the POSIX way.
*
* @return 0 on success, or -1 w/ errno
* @raise EFAULT if the `n` bytes at `p` aren't valid memory
@ -41,17 +40,23 @@ int getentropy(void *p, size_t n) {
} else if ((!p && n)) {
rc = efault();
} else if (IsXnu() || IsOpenbsd()) {
if (sys_getentropy(p, n))
notpossible;
rc = 0;
rc = sys_getentropy(p, n);
} else {
BLOCK_SIGNALS;
ssize_t got;
BLOCK_CANCELATION;
if (__getrandom(p, n, 0) != n)
notpossible;
ALLOW_CANCELATION;
ALLOW_SIGNALS;
rc = 0;
for (size_t i = 0; i < n; i += got) {
got = __getrandom(p + i, n - i, 0);
if (got == -1) {
if (errno == EAGAIN || errno == EINTR) {
got = 0;
} else {
rc = -1;
break;
}
}
}
ALLOW_CANCELATION;
}
STRACE("getentropy(%p, %'zu) → %'ld% m", p, n, rc);
return rc;