diff --git a/crypto/trace.c b/crypto/trace.c index 51387641de..3e10d91fc2 100644 --- a/crypto/trace.c +++ b/crypto/trace.c @@ -475,7 +475,7 @@ BIO *OSSL_trace_begin(int category) char *prefix = NULL; category = ossl_trace_get_category(category); - if (category < 0) + if (category < 0 || !OSSL_trace_enabled(category)) return NULL; channel = trace_channels[category].bio; diff --git a/doc/man3/OSSL_trace_enabled.pod b/doc/man3/OSSL_trace_enabled.pod index da78eba234..987dd7f91a 100644 --- a/doc/man3/OSSL_trace_enabled.pod +++ b/doc/man3/OSSL_trace_enabled.pod @@ -97,9 +97,10 @@ I is enabled, i.e., if the tracing facility has been statically enabled (see L below) and a trace channel has been registered using L or L. -OSSL_trace_begin() is used to starts a tracing section, and get the -channel for the given I in form of a BIO. +OSSL_trace_begin() is used to start a tracing section, +and get the channel for the given I in form of a BIO. This BIO can only be used for output. +The pointer returned is NULL if the category is invalid or not enabled. OSSL_trace_end() is used to end a tracing section. @@ -211,6 +212,9 @@ expands to =head1 NOTES +It is not needed to guard trace output function calls like +I by I. + If producing the trace output requires carrying out auxiliary calculations, this auxiliary code should be placed inside a conditional block which is executed only if the trace category is enabled.