bionic: make NONBLOCK call to getrandom
By default getrandom() blocks if the entropy pool has not yet been initialized.
This will be an issue when init was first executed in some kernels.
This CL makes a check of getrandom readyness, by adding the GRND_NONBLOCK flag.
In such case, getrandom() does not block returns -1 with errno set to EAGAIN.
Test: on M/S devices
Bug: 33059407
Change-Id: I2a2ba8372a5e1c336852ba2ab77cdaac03c90389
diff --git a/libc/bionic/getentropy_linux.c b/libc/bionic/getentropy_linux.c
index 98fb6fb..cf0aa45 100644
--- a/libc/bionic/getentropy_linux.c
+++ b/libc/bionic/getentropy_linux.c
@@ -102,7 +102,7 @@
ret = getentropy_getrandom(buf, len);
if (ret != -1)
return (ret);
- if (errno != ENOSYS)
+ if (errno != ENOSYS && errno != EAGAIN)
return (-1);
/*
@@ -200,7 +200,11 @@
if (len > 256)
return (-1);
do {
- ret = syscall(SYS_getrandom, buf, len, 0);
+ /*
+ * Use GRND_NONBLOCK to avoid blocking before the
+ * entropy pool has been initialized
+ */
+ ret = syscall(SYS_getrandom, buf, len, GRND_NONBLOCK);
} while (ret == -1 && errno == EINTR);
if ((size_t)ret != len)