[compiler-rt] [compiler-rt] making getrandom call blocking. (PR #78340)

[David CARLIER via llvm-commits]

https://github.com/devnexen updated https://github.com/llvm/llvm-project/pull/78340

>From 63462fd187eccc997046849c822e7a1b0841c73e Mon Sep 17 00:00:00 2001
From: David Carlier <devnexen at gmail.com>
Date: Tue, 16 Jan 2024 20:02:25 +0000
Subject: [PATCH] [compiler-rt] making getrandom call blocking.

except when `GRND_NONBLOCK` is present in the flags.
---
 .../sanitizer_common/sanitizer_common_interceptors.inc    | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc b/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc
index 77fa1b4965a7a4..1b56bebac64e68 100644
--- a/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc
+++ b/compiler-rt/lib/sanitizer_common/sanitizer_common_interceptors.inc
@@ -9965,7 +9965,13 @@ INTERCEPTOR(void, sl_free, void *sl, int freeall) {
 INTERCEPTOR(SSIZE_T, getrandom, void *buf, SIZE_T buflen, unsigned int flags) {
   void *ctx;
   COMMON_INTERCEPTOR_ENTER(ctx, getrandom, buf, buflen, flags);
-  SSIZE_T n = REAL(getrandom)(buf, buflen, flags);
+  // If GRND_NONBLOCK is set in the flags, it is non blocking.
+  static const int grnd_nonblock = 1; 
+  SSIZE_T n;
+  if ((flags & grnd_nonblock))
+    n = REAL(getrandom)(buf, buflen, flags);
+  else
+    n = COMMON_INTERCEPTOR_BLOCK_REAL(getrandom)(buf, buflen, flags);
   if (n > 0) {
     COMMON_INTERCEPTOR_WRITE_RANGE(ctx, buf, n);
   }