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| author | Paul Eggert <eggert@cs.ucla.edu> | 2020-09-20 11:48:17 -0700 |
|---|---|---|
| committer | Paul Eggert <eggert@cs.ucla.edu> | 2020-09-20 15:48:44 -0700 |
| commit | 8ba9126d00bfe1ab77a5c820c58c68933d4df85c (patch) | |
| tree | 84ebf8918a3ba65aba4229ec55f5670733adcae5 /modules/c-stack | |
| parent | 17a6bcd48f271a42880eb9657002de2a497a6a7e (diff) | |
| download | gnulib-8ba9126d00bfe1ab77a5c820c58c68933d4df85c.tar.gz | |
c-stack: improve checking if !libsigsegv
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.
Diffstat (limited to 'modules/c-stack')
| -rw-r--r-- | modules/c-stack | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/modules/c-stack b/modules/c-stack index ca2c208e1a..8c898eb9e9 100644 --- a/modules/c-stack +++ b/modules/c-stack @@ -7,15 +7,19 @@ lib/c-stack.c m4/c-stack.m4 Depends-on: -gettext-h errno exitfail +getprogname +gettext-h ignore-value -unistd +intprops +inttypes +libsigsegv raise sigaction -libsigsegv -getprogname +stdbool +stddef +unistd configure.ac: gl_C_STACK |