From 46b5e7c4b5befbf6ac86d827a3a58f1f02c7338e Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Sun, 12 Aug 2018 18:46:01 -0400 Subject: [PATCH] Revert "Distinguish printf-like functions that support %m from those that don't." This reverts commit 3a60c8ff892a8242b907f44702bfd9f1ff877d45. Buildfarm results show that that caused a whole bunch of new warnings on platforms where gcc believes the local printf to be non-POSIX-compliant. This problem outweighs the hypothetical-anyway possibility of getting warnings for misuse of %m. We could use gnu_printf archetype when we've substituted src/port/snprintf.c, but that brings us right back to the problem of not getting warnings for %m. A possible answer is to attack it in the other direction by insisting that %m support be included in printf's feature set, but that will take more investigation. In the meantime, revert the previous change, and update the comment for PGAC_C_PRINTF_ARCHETYPE to more fully explain what's going on. Discussion: https://postgr.es/m/2975.1526862605@sss.pgh.pa.us --- config/c-compiler.m4 | 20 +++++++++++++------- configure | 6 +++--- src/include/c.h | 6 +----- src/include/pg_config.h.in | 4 ++-- src/include/utils/elog.h | 30 +++++++++++++++--------------- 5 files changed, 34 insertions(+), 32 deletions(-) diff --git a/config/c-compiler.m4 b/config/c-compiler.m4 index dfcc1c6600..67675a31bb 100644 --- a/config/c-compiler.m4 +++ b/config/c-compiler.m4 @@ -19,12 +19,18 @@ fi])# PGAC_C_SIGNED # PGAC_C_PRINTF_ARCHETYPE # ----------------------- -# Set the format archetype used by gcc to check elog/ereport functions. -# This should accept %m, whether or not the platform's printf does. -# We use "gnu_printf" if possible, which does that, although in some cases -# it might do more than we could wish. +# Select the format archetype to be used by gcc to check printf-type functions. +# We prefer "gnu_printf", which matches the features glibc supports, notably +# %m, 'z' and 'll' width modifiers ('ll' only matters if int64 requires it), +# and argument order control if we're doing --enable-nls. On platforms where +# the native printf doesn't have 'z'/'ll' or arg control, we replace it with +# src/port/snprintf.c which does, so that the only potential mismatch here is +# whether or not %m is supported. We need that for elog/ereport, so we live +# with the fact that erroneous use of %m in plain printf calls won't be +# detected. (It appears that many versions of gcc/clang wouldn't report it +# even if told to check according to plain printf archetype, anyway.) AC_DEFUN([PGAC_PRINTF_ARCHETYPE], -[AC_CACHE_CHECK([for printf format archetype for %m], pgac_cv_printf_archetype, +[AC_CACHE_CHECK([for printf format archetype], pgac_cv_printf_archetype, [ac_save_c_werror_flag=$ac_c_werror_flag ac_c_werror_flag=yes AC_COMPILE_IFELSE([AC_LANG_PROGRAM( @@ -34,8 +40,8 @@ __attribute__((format(gnu_printf, 2, 3)));], [])], [pgac_cv_printf_archetype=gnu_printf], [pgac_cv_printf_archetype=printf]) ac_c_werror_flag=$ac_save_c_werror_flag]) -AC_DEFINE_UNQUOTED([PG_PRINTF_ATTRIBUTE_M], [$pgac_cv_printf_archetype], - [Define as a format archetype that accepts %m, if available, else printf.]) +AC_DEFINE_UNQUOTED([PG_PRINTF_ATTRIBUTE], [$pgac_cv_printf_archetype], + [Define to gnu_printf if compiler supports it, else printf.]) ])# PGAC_PRINTF_ARCHETYPE diff --git a/configure b/configure index 5f8ec55837..26652133d5 100755 --- a/configure +++ b/configure @@ -13362,8 +13362,8 @@ _ACEOF ;; esac -{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for printf format archetype for %m" >&5 -$as_echo_n "checking for printf format archetype for %m... " >&6; } +{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for printf format archetype" >&5 +$as_echo_n "checking for printf format archetype... " >&6; } if ${pgac_cv_printf_archetype+:} false; then : $as_echo_n "(cached) " >&6 else @@ -13394,7 +13394,7 @@ fi $as_echo "$pgac_cv_printf_archetype" >&6; } cat >>confdefs.h <<_ACEOF -#define PG_PRINTF_ATTRIBUTE_M $pgac_cv_printf_archetype +#define PG_PRINTF_ATTRIBUTE $pgac_cv_printf_archetype _ACEOF diff --git a/src/include/c.h b/src/include/c.h index 0a4757e29f..1e50103095 100644 --- a/src/include/c.h +++ b/src/include/c.h @@ -126,14 +126,10 @@ /* GCC and XLC support format attributes */ #if defined(__GNUC__) || defined(__IBMC__) #define pg_attribute_format_arg(a) __attribute__((format_arg(a))) -/* Use for functions wrapping stdio's printf, which often doesn't take %m: */ -#define pg_attribute_printf(f,a) __attribute__((format(printf, f, a))) -/* Use for elog/ereport, which implement %m for themselves: */ -#define pg_attribute_printf_m(f,a) __attribute__((format(PG_PRINTF_ATTRIBUTE_M, f, a))) +#define pg_attribute_printf(f,a) __attribute__((format(PG_PRINTF_ATTRIBUTE, f, a))) #else #define pg_attribute_format_arg(a) #define pg_attribute_printf(f,a) -#define pg_attribute_printf_m(f,a) #endif /* GCC, Sunpro and XLC support aligned, packed and noreturn */ diff --git a/src/include/pg_config.h.in b/src/include/pg_config.h.in index 05775a3405..b7e469670f 100644 --- a/src/include/pg_config.h.in +++ b/src/include/pg_config.h.in @@ -809,8 +809,8 @@ /* PostgreSQL major version as a string */ #undef PG_MAJORVERSION -/* Define as a format archetype that accepts %m, if available, else printf. */ -#undef PG_PRINTF_ATTRIBUTE_M +/* Define to gnu_printf if compiler supports it, else printf. */ +#undef PG_PRINTF_ATTRIBUTE /* PostgreSQL version as a string */ #undef PG_VERSION diff --git a/src/include/utils/elog.h b/src/include/utils/elog.h index 6b618a52d0..4350b120aa 100644 --- a/src/include/utils/elog.h +++ b/src/include/utils/elog.h @@ -152,25 +152,25 @@ extern int errcode(int sqlerrcode); extern int errcode_for_file_access(void); extern int errcode_for_socket_access(void); -extern int errmsg(const char *fmt,...) pg_attribute_printf_m(1, 2); -extern int errmsg_internal(const char *fmt,...) pg_attribute_printf_m(1, 2); +extern int errmsg(const char *fmt,...) pg_attribute_printf(1, 2); +extern int errmsg_internal(const char *fmt,...) pg_attribute_printf(1, 2); extern int errmsg_plural(const char *fmt_singular, const char *fmt_plural, - unsigned long n,...) pg_attribute_printf_m(1, 4) pg_attribute_printf_m(2, 4); + unsigned long n,...) pg_attribute_printf(1, 4) pg_attribute_printf(2, 4); -extern int errdetail(const char *fmt,...) pg_attribute_printf_m(1, 2); -extern int errdetail_internal(const char *fmt,...) pg_attribute_printf_m(1, 2); +extern int errdetail(const char *fmt,...) pg_attribute_printf(1, 2); +extern int errdetail_internal(const char *fmt,...) pg_attribute_printf(1, 2); -extern int errdetail_log(const char *fmt,...) pg_attribute_printf_m(1, 2); +extern int errdetail_log(const char *fmt,...) pg_attribute_printf(1, 2); extern int errdetail_log_plural(const char *fmt_singular, const char *fmt_plural, - unsigned long n,...) pg_attribute_printf_m(1, 4) pg_attribute_printf_m(2, 4); + unsigned long n,...) pg_attribute_printf(1, 4) pg_attribute_printf(2, 4); extern int errdetail_plural(const char *fmt_singular, const char *fmt_plural, - unsigned long n,...) pg_attribute_printf_m(1, 4) pg_attribute_printf_m(2, 4); + unsigned long n,...) pg_attribute_printf(1, 4) pg_attribute_printf(2, 4); -extern int errhint(const char *fmt,...) pg_attribute_printf_m(1, 2); +extern int errhint(const char *fmt,...) pg_attribute_printf(1, 2); /* * errcontext() is typically called in error context callback functions, not @@ -184,7 +184,7 @@ extern int errhint(const char *fmt,...) pg_attribute_printf_m(1, 2); extern int set_errcontext_domain(const char *domain); -extern int errcontext_msg(const char *fmt,...) pg_attribute_printf_m(1, 2); +extern int errcontext_msg(const char *fmt,...) pg_attribute_printf(1, 2); extern int errhidestmt(bool hide_stmt); extern int errhidecontext(bool hide_ctx); @@ -243,13 +243,13 @@ extern int getinternalerrposition(void); #endif /* HAVE__VA_ARGS */ extern void elog_start(const char *filename, int lineno, const char *funcname); -extern void elog_finish(int elevel, const char *fmt,...) pg_attribute_printf_m(2, 3); +extern void elog_finish(int elevel, const char *fmt,...) pg_attribute_printf(2, 3); /* Support for constructing error strings separately from ereport() calls */ extern void pre_format_elog_string(int errnumber, const char *domain); -extern char *format_elog_string(const char *fmt,...) pg_attribute_printf_m(1, 2); +extern char *format_elog_string(const char *fmt,...) pg_attribute_printf(1, 2); /* Support for attaching context information to error reports */ @@ -428,9 +428,9 @@ extern void set_syslog_parameters(const char *ident, int facility); #endif /* - * Write errors to stderr (or by comparable means when stderr is not - * available). Used before ereport/elog can be used safely (memory context, - * GUC load etc). Note that this does *not* accept "%m". + * Write errors to stderr (or by equal means when stderr is + * not available). Used before ereport/elog can be used + * safely (memory context, GUC load etc) */ extern void write_stderr(const char *fmt,...) pg_attribute_printf(1, 2);