From 970468f937408883e33242d7c1417cfc5e56e8f5 Mon Sep 17 00:00:00 2001 From: Bartosz Taudul Date: Fri, 28 Oct 2022 01:21:52 +0200 Subject: Override dlclose() to do nothing. Provide a custom no-op implementation of dlclose(), in order to prevent shared object data from disappearing from profiler view. The server makes queries for program executable code, which has to be always available, otherwise wrong data may be provided, or the program may crash, due to referencing no longer mapped memory. The dlclose() documentation states that the function internally decreases the reference count, and only does unload the shared object when the count reaches zero. There is no guarantee that the shared object data will be unloaded immediately after any dlclose call originating from the program. This function override exploits this fact. --- public/TracyClient.cpp | 1 + public/client/TracyOverride.cpp | 26 ++++++++++++++++++++++++++ 2 files changed, 27 insertions(+) create mode 100644 public/client/TracyOverride.cpp diff --git a/public/TracyClient.cpp b/public/TracyClient.cpp index 4aa4647a..77f81a4a 100644 --- a/public/TracyClient.cpp +++ b/public/TracyClient.cpp @@ -28,6 +28,7 @@ #include "client/tracy_rpmalloc.cpp" #include "client/TracyDxt1.cpp" #include "client/TracyAlloc.cpp" +#include "client/TracyOverride.cpp" #if TRACY_HAS_CALLSTACK == 2 || TRACY_HAS_CALLSTACK == 3 || TRACY_HAS_CALLSTACK == 4 || TRACY_HAS_CALLSTACK == 6 # include "libbacktrace/alloc.cpp" diff --git a/public/client/TracyOverride.cpp b/public/client/TracyOverride.cpp new file mode 100644 index 00000000..591508a7 --- /dev/null +++ b/public/client/TracyOverride.cpp @@ -0,0 +1,26 @@ +#ifdef TRACY_ENABLE +# ifdef __linux__ +# include "TracyDebug.hpp" +# ifdef TRACY_VERBOSE +# include +# include +# endif + +extern "C" int dlclose( void* hnd ) +{ +#ifdef TRACY_VERBOSE + struct link_map* lm; + if( dlinfo( hnd, RTLD_DI_LINKMAP, &lm ) == 0 ) + { + TracyDebug( "Overriding dlclose for %s\n", lm->l_name ); + } + else + { + TracyDebug( "Overriding dlclose for unknown object (%s)\n", dlerror() ); + } +#endif + return 0; +} + +# endif +#endif -- cgit v1.2.3