From 5355a2400e847b1a7e7a3d9eea9516588d0fad91 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Sun, 18 May 2025 12:45:55 -0400 Subject: [PATCH] Make our usage of memset_s() conform strictly to the C11 standard. Per the letter of the C11 standard, one must #define __STDC_WANT_LIB_EXT1__ as 1 before including in order to have access to memset_s(). It appears that many platforms are lenient about this, because we weren't doing it and yet the code appeared to work anyway. But we now find that with -std=c11, macOS is strict and doesn't declare memset_s, leading to compile failures since we try to use it anyway. (Given the lack of prior reports, perhaps this is new behavior in the latest SDK? No matter, we're clearly in the wrong.) In addition to the immediate problem, which could be fixed merely by adding the needed #define to explicit_bzero.c, it seems possible that our configure-time probe for memset_s() could fail in case a platform implements the function in some odd way due to this spec requirement. This concern can be fixed in largely the same way that we dealt with strchrnul() in 6da2ba1d8: switch to using a declaration-based configure probe instead of a does-it-link probe. Back-patch to v13 where we started using memset_s(). Reported-by: Lakshmi Narayana Velayudam Author: Tom Lane Discussion: https://postgr.es/m/CAA4pTnLcKGG78xeOjiBr5yS7ZeE-Rh=FaFQQGOO=nPzA1L8yEA@mail.gmail.com Backpatch-through: 13 --- configure | 15 ++++++++++++++- configure.ac | 3 ++- meson.build | 14 ++++++++------ src/include/pg_config.h.in | 7 ++++--- src/port/explicit_bzero.c | 4 +++- 5 files changed, 31 insertions(+), 12 deletions(-) diff --git a/configure b/configure index 6ea253f5063..49294304b2b 100755 --- a/configure +++ b/configure @@ -15272,7 +15272,7 @@ fi LIBS_including_readline="$LIBS" LIBS=`echo "$LIBS" | sed -e 's/-ledit//g' -e 's/-lreadline//g'` -for ac_func in backtrace_symbols copyfile copy_file_range getifaddrs getpeerucred inet_pton kqueue mbstowcs_l memset_s posix_fallocate ppoll pthread_is_threaded_np setproctitle setproctitle_fast strsignal syncfs sync_file_range uselocale wcstombs_l +for ac_func in backtrace_symbols copyfile copy_file_range getifaddrs getpeerucred inet_pton kqueue mbstowcs_l posix_fallocate ppoll pthread_is_threaded_np setproctitle setproctitle_fast strsignal syncfs sync_file_range uselocale wcstombs_l do : as_ac_var=`$as_echo "ac_cv_func_$ac_func" | $as_tr_sh` ac_fn_c_check_func "$LINENO" "$ac_func" "$as_ac_var" @@ -15828,6 +15828,19 @@ cat >>confdefs.h <<_ACEOF #define HAVE_DECL_STRCHRNUL $ac_have_decl _ACEOF +ac_fn_c_check_decl "$LINENO" "memset_s" "ac_cv_have_decl_memset_s" "#define __STDC_WANT_LIB_EXT1__ 1 +#include +" +if test "x$ac_cv_have_decl_memset_s" = xyes; then : + ac_have_decl=1 +else + ac_have_decl=0 +fi + +cat >>confdefs.h <<_ACEOF +#define HAVE_DECL_MEMSET_S $ac_have_decl +_ACEOF + # This is probably only present on macOS, but may as well check always ac_fn_c_check_decl "$LINENO" "F_FULLFSYNC" "ac_cv_have_decl_F_FULLFSYNC" "#include diff --git a/configure.ac b/configure.ac index f398184645f..3a8da4476d1 100644 --- a/configure.ac +++ b/configure.ac @@ -1757,7 +1757,6 @@ AC_CHECK_FUNCS(m4_normalize([ inet_pton kqueue mbstowcs_l - memset_s posix_fallocate ppoll pthread_is_threaded_np @@ -1803,6 +1802,8 @@ AC_CHECK_DECLS([strlcat, strlcpy, strnlen]) AC_CHECK_DECLS([preadv], [], [], [#include ]) AC_CHECK_DECLS([pwritev], [], [], [#include ]) AC_CHECK_DECLS([strchrnul], [], [], [#include ]) +AC_CHECK_DECLS([memset_s], [], [], [#define __STDC_WANT_LIB_EXT1__ 1 +#include ]) # This is probably only present on macOS, but may as well check always AC_CHECK_DECLS(F_FULLFSYNC, [], [], [#include ]) diff --git a/meson.build b/meson.build index 78be2687d67..76775989329 100644 --- a/meson.build +++ b/meson.build @@ -2470,6 +2470,7 @@ decl_checks += [ ['preadv', 'sys/uio.h'], ['pwritev', 'sys/uio.h'], ['strchrnul', 'string.h'], + ['memset_s', 'string.h', '#define __STDC_WANT_LIB_EXT1__ 1'], ] # Check presence of some optional LLVM functions. @@ -2483,21 +2484,23 @@ endif foreach c : decl_checks func = c.get(0) header = c.get(1) - args = c.get(2, {}) + prologue = c.get(2, '') + args = c.get(3, {}) varname = 'HAVE_DECL_' + func.underscorify().to_upper() found = cc.compiles(''' -#include <@0@> +@0@ +#include <@1@> int main() { -#ifndef @1@ - (void) @1@; +#ifndef @2@ + (void) @2@; #endif return 0; } -'''.format(header, func), +'''.format(prologue, header, func), name: 'test whether @0@ is declared'.format(func), # need to add cflags_warn to get at least # -Werror=unguarded-availability-new if applicable @@ -2726,7 +2729,6 @@ func_checks = [ ['inet_pton'], ['kqueue'], ['mbstowcs_l'], - ['memset_s'], ['mkdtemp'], ['posix_fadvise'], ['posix_fallocate'], diff --git a/src/include/pg_config.h.in b/src/include/pg_config.h.in index 0ee4a63eaa6..1371ac055f4 100644 --- a/src/include/pg_config.h.in +++ b/src/include/pg_config.h.in @@ -103,6 +103,10 @@ `LLVMCreatePerfJITEventListener', and to 0 if you don't. */ #undef HAVE_DECL_LLVMCREATEPERFJITEVENTLISTENER +/* Define to 1 if you have the declaration of `memset_s', and to 0 if you + don't. */ +#undef HAVE_DECL_MEMSET_S + /* Define to 1 if you have the declaration of `posix_fadvise', and to 0 if you don't. */ #undef HAVE_DECL_POSIX_FADVISE @@ -301,9 +305,6 @@ /* Define to 1 if you have the header file. */ #undef HAVE_MEMORY_H -/* Define to 1 if you have the `memset_s' function. */ -#undef HAVE_MEMSET_S - /* Define to 1 if you have the `mkdtemp' function. */ #undef HAVE_MKDTEMP diff --git a/src/port/explicit_bzero.c b/src/port/explicit_bzero.c index 735e21c8b36..7d2ad7439f7 100644 --- a/src/port/explicit_bzero.c +++ b/src/port/explicit_bzero.c @@ -12,9 +12,11 @@ *------------------------------------------------------------------------- */ +#define __STDC_WANT_LIB_EXT1__ 1 /* needed to access memset_s() */ + #include "c.h" -#if defined(HAVE_MEMSET_S) +#if HAVE_DECL_MEMSET_S void explicit_bzero(void *buf, size_t len) -- 2.39.5