* lib/c-stack.c: Omit mention of HAVE_SIGALTSTACK, since
the code is used only if a test for sigaltstack worked
in some other way.
* m4/c-stack.m4 (gl_PREREQ_C_STACK): Do not require gl_LIBSIGSEGV;
instead, execute gl_LIBSIGSEGV only if needed (because the XSI
heuristic does not work).
* modules/c-stack (Files): Add m4/libsigsegv.m4, since
we no longer require the libsigsegv module.
(Depends-on): Depend on havelib, not libsigsegv.
* lib/c-stack.c (die): In the typical case, use just one 'write'
syscall to output the diagnostic, as this lessens interleaving.
(die, c_stack_action): Assume C99.
* modules/c-stack (Depends-on): Add c99, mempcpy.
If SIGINFO_WORKS, do not treat a null pointer dereference as if it
were a stack overflow. Use uintptr_t and INT_ADD_WRAPV to avoid
unlikely pointer overflow. Also, fix some obsolete code and typos.
I found these problems while looking into this bug report:
https://lists.gnu.org/r/grep-devel/2020-09/msg00053.html
* lib/c-stack.c: Include c-stack.h first, to test interface.
Include inttypes.h for UINTPTR_MAX, stdbool.h, stddef.h for
max_align_t, intprops.h for INT_ADD_WRAPV.
(USE_LIBSIGSEGV): New macro; use it to simplify later code.
(SIGSTKSZ): Simplify setup. Work around libsigsegv bug only
for libsigsegv 2.8 and earlier since the bug should be fixed
after that.
(alternate_signal_stack): Use max_align_t instead of doing it by hand.
(segv_handler, overflow_handler, segv_handler) [DEBUG]:
Assume sprintf returns byte count; this assumption is safe now.
(page_size): New static volatile variable, since sysconf isn’t
documented to be async-signal-safe on Solaris. This variable is
present and used if (!USE_LIBSIGSEGV && HAVE_SIGALTSTACK &&
HAVE_DECL_SIGALTSTACK && HAVE_STACK_OVERFLOW_HANDLING &&
SIGINFO_WORKS).
(segv_handler): Use it if present. Never report null pointer
dereference as a stack overflow. Check for (unlikely) unsigned
and/or pointer overflow.
* m4/c-stack.m4 (AC_SYS_XSI_STACK_OVERFLOW_HEURISTIC):
Rename cache variables to gl_cv_sys_stack_overflow_works
and gl_cv_sys_xsi_stack_overflow_heuristic.
All uses changed.
(gl_PREREQ_C_STACK): Do not require AC_FUNC_ALLOCA, since
c-stack no longer uses STACK_DIRECTION.
Do not check for unistd.h, since we depend on unistd.
Fix shell typo ‘$"ac_cv_sys_xsi_stack_overflow_heuristic"’.
* modules/c-stack (Depends-on): Sort. Add intprops, inttypes,
stdbool, stddef.
... instead of requiring progname to be used (or program_name to be
provided).
* lib/argmatch.c: Do not include progname.h.
[TEST] (program_name): Do not define.
[TEST] (main): Call getprogname instead of using program_name.
* lib/c-stack.c: Do not include progname.h.
(program_name): Do not define.
(die): Call getprogname instead of using program_name.
* lib/chdir-long.c: Do not include progname.h.
[TEST_CHDIR] (main): Do not set program_name.
* lib/error.c [!_LIBC]: Include progname.h.
[!_LIBC] (program_name): Define using getprogname.
* lib/euidaccess.c: Do not include progname.h.
[TEST] (main): Do not set program_name.
* lib/git-merge-changelog.c: Include getprogname.h instead of
progname.h.
(usage): Call getprogname instead of using program_name.
(main): Likewise. Stop calling set_program_name.
* lib/group-member.c: Do not include progname.h.
[TEST] (main): Do not set program_name.
* modules/argmatch (Depends-on): Add getprogname.
* modules/c-stack (Depends-on): Likewise.
* modules/error (Depends-on): Likewise.
* modules/git-merge-changelog (Depends-on): Likewise.
Also remove progname.
* modules/c-stack (Depends-on): Add libsigsegv.
* modules/c-stack-tests (Makefile.am): Link with libsigsegv, if
needed.
* lib/c-stack.c (SIGSTKSZ): Define fallback.
(segv_handler, overflow_handler, c_stack_action)
[HAVE_LIBSIGSEGV && !HAVE_XSI_STACK_OVERFLOW_HEURISTIC]: Add new
implementation when libsigsegv is available, but only when using
the library is necessary.
* m4/c-stack.m4 (AC_SYS_XSI_STACK_OVERFLOW_HEURISTIC): Add
comment, explaining why XSI check fails on Linux.
(gl_PREREQ_C_STACK): Supply LIBCSTACK, LTLIBCSTACK.
* tests/test-c-stack2.sh: Tweak skip message.
* NEWS: Document new link-time requirements.
Signed-off-by: Eric Blake <ebb9@byu.net>
