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authorSebastian Huber <sebastian.huber@embedded-brains.de>2017-11-20 08:08:30 +0100
committerSebastian Huber <sebastian.huber@embedded-brains.de>2017-11-20 08:08:30 +0100
commit70f23e475b23af25e2035e2b5cfe1f5a8a7ea9f9 (patch)
treec9a5e6d943e3e42820b431f0a25658970a8dbbe5 /bsp-howto
parente2a1a3ab2a4d137c3a68250c9f1ddc5f2d9af7e4 (diff)
downloadrtems-docs-70f23e475b23af25e2035e2b5cfe1f5a8a7ea9f9.tar.bz2
Clarify INTERNAL_ERROR_ARC4RANDOM_GETENTROPY_FAIL
Update #3239.
Diffstat (limited to 'bsp-howto')
-rw-r--r--bsp-howto/getentropy.rst5
1 files changed, 4 insertions, 1 deletions
diff --git a/bsp-howto/getentropy.rst b/bsp-howto/getentropy.rst
index b460450..10303a3 100644
--- a/bsp-howto/getentropy.rst
+++ b/bsp-howto/getentropy.rst
@@ -21,7 +21,10 @@ turn are used by various cryptographic functions.
suitable for such applications.
The :c:func:`getentropy` implementation must fill the specified memory region
-of the given size with random numbers and return 0 on success.
+of the given size with random numbers and return 0 on success. A non-zero
+return may cause the :c:macro:`INTERNAL_ERROR_ARC4RANDOM_GETENTROPY_FAIL`
+internal error by one of the
+`ARC4RANDOM(3) <https://man.openbsd.org/arc4random.3>`_ functions.
In general, for embedded systems it is not easy to get some real entropy. Normally,
that can only be reached with some extra hardware support. Some microcontrollers