[PATCH 0/3] Reentrancy
Pekka Seppänen
pexu@sourceware.mail.kapsi.fi
Wed Aug 30 09:16:21 GMT 2023
Hi,
The following patch series provides small (one line) fixes for
newlib/libc
reentrancy when using --enable-newlib-reent-thread-local and uses the
existing
infrastructure to do that:
- There were a few locations on which _errno member was directly
accessed.
As struct _reent is not available if _REENT_THREAD_LOCAL is defined, any
accesses to errno shall be done using the corresponding _REENT_ERRNO()
macro.
Should be self-explanatory.
- __getreent() did not check that struct _reent and _impure_ptr were
available. Both <sys/reent.h> and impure.c, that declare and define
_impure_ptr, use similar #ifdef/ifndef gate. If thread-local storage is
used
the allocated objects are not related to each other. Therefore
__getreent()
does not exist even at a concept level, hence should not be provided at
all.
- As _Thread_local might not be available (as in that particular
keyword),
<sys/reent.h> shall include <sys/cdefs.h> that will provide a correct
mapping,
should the compiler actually support thread-local storage. A prime
example is
libstdc++ configure, which uses #include <math.h> in some of the
generated
checks. Essentially any C++ target is affected and possibly C targets
in
near future as C23 uses thread_local, not _Thread_local.
It should be noted that libgloss is affected by similar reentrancy
issues, but
I decided not to touch those.
-- Pekka
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