https://gcc.gnu.org/g:d46138a434b1b372b84dfeef25e8b79679196179
commit r16-1153-gd46138a434b1b372b84dfeef25e8b79679196179
Author: Ronan Desplanques <desplanq...@adacore.com>
Date: Thu Jan 30 16:02:31 2025 +0100
ada: Mitigate issue with tracebacks
The way we fetch the path to shared objects for traceback generation is
not perfectly precise. This patch adds a sanity check to mitigate the
consequences of incorrect shared object paths. It's motivated by a real
world failure in a GNATSAS test.
gcc/ada/ChangeLog:
* libgnat/s-trasym__dwarf.adb (Init_Module): Add mitigation.
Diff:
---
gcc/ada/libgnat/s-trasym__dwarf.adb | 18 ++++++++++++++++++
1 file changed, 18 insertions(+)
diff --git a/gcc/ada/libgnat/s-trasym__dwarf.adb
b/gcc/ada/libgnat/s-trasym__dwarf.adb
index 45af884b61fe..1b4b807f5669 100644
--- a/gcc/ada/libgnat/s-trasym__dwarf.adb
+++ b/gcc/ada/libgnat/s-trasym__dwarf.adb
@@ -41,6 +41,7 @@ with System.Soft_Links;
with System.CRTL;
with System.Dwarf_Lines;
with System.Exception_Traces;
+with System.OS_Lib;
with System.Standard_Library;
with System.Traceback_Entries;
with System.Strings;
@@ -413,6 +414,23 @@ package body System.Traceback.Symbolic is
return;
end if;
+ -- On some platforms, we use dladdr and the dli_fname field to get the
+ -- pathname, but that pathname might be relative and not point to the
+ -- right thing in our context. That happens when the executable is
+ -- dynamically linked and was started through execvp; dli_fname only
+ -- contains the executable name passed to execvp in that case.
+ --
+ -- Because of this, we might be about to open a file that's in fact not
+ -- a shared object but something completely unrelated. It's hard to
+ -- detect this in general, but we perform a sanity check that
+ -- Module_Name does not designate a directory; if it does, it's
+ -- definitely not a shared object.
+
+ if System.OS_Lib.Is_Directory (Module_Name) then
+ Success := False;
+ return;
+ end if;
+
Open (Module_Name, Module.C, Success);
-- If a module can't be opened just return now, we just cannot give more
