From 8eb4a9312c95be56cdb31f5411eddc2cb2ba89be Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Mon, 21 Jan 2019 12:07:02 -0500 Subject: [PATCH] Avoid thread-safety problem in ecpglib. ecpglib attempts to force the LC_NUMERIC locale to "C" while reading server output, to avoid problems with strtod() and related functions. Historically it's just issued setlocale() calls to do that, but that has major problems if we're in a threaded application. setlocale() itself is not required by POSIX to be thread-safe (and indeed is not, on recent OpenBSD). Moreover, its effects are process-wide, so that we could cause unexpected results in other threads, or another thread could change our setting. On platforms having uselocale(), which is required by POSIX:2008, we can avoid these problems by using uselocale() instead. Windows goes its own way as usual, but we can make it safe by using _configthreadlocale(). Platforms having neither continue to use the old code, but that should be pretty much nobody among current systems. This should get back-patched, but let's see what the buildfarm thinks of it first. Michael Meskes and Tom Lane; thanks also to Takayuki Tsunakawa. Discussion: https://postgr.es/m/31420.1547783697@sss.pgh.pa.us --- configure | 2 +- configure.in | 1 + src/include/pg_config.h.in | 3 ++ src/include/pg_config.h.win32 | 3 ++ src/interfaces/ecpg/ecpglib/descriptor.c | 37 +++++++++++++---- src/interfaces/ecpg/ecpglib/ecpglib_extern.h | 11 +++++ src/interfaces/ecpg/ecpglib/execute.c | 42 +++++++++++++++++++- 7 files changed, 90 insertions(+), 9 deletions(-) diff --git a/configure b/configure index 7602e65416..1e69edacde 100755 --- a/configure +++ b/configure @@ -15209,7 +15209,7 @@ fi LIBS_including_readline="$LIBS" LIBS=`echo "$LIBS" | sed -e 's/-ledit//g' -e 's/-lreadline//g'` -for ac_func in cbrt clock_gettime copyfile fdatasync getifaddrs getpeerucred getrlimit mbstowcs_l memmove poll posix_fallocate ppoll pstat pthread_is_threaded_np readlink setproctitle setproctitle_fast setsid shm_open strchrnul strsignal symlink sync_file_range utime utimes wcstombs_l +for ac_func in cbrt clock_gettime copyfile fdatasync getifaddrs getpeerucred getrlimit mbstowcs_l memmove poll posix_fallocate ppoll pstat pthread_is_threaded_np readlink setproctitle setproctitle_fast setsid shm_open strchrnul strsignal symlink sync_file_range uselocale utime utimes 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" diff --git a/configure.in b/configure.in index d599ad85cc..556186cf2d 100644 --- a/configure.in +++ b/configure.in @@ -1618,6 +1618,7 @@ AC_CHECK_FUNCS(m4_normalize([ strsignal symlink sync_file_range + uselocale utime utimes wcstombs_l diff --git a/src/include/pg_config.h.in b/src/include/pg_config.h.in index 9d99816eae..2c899a1569 100644 --- a/src/include/pg_config.h.in +++ b/src/include/pg_config.h.in @@ -691,6 +691,9 @@ /* Define to 1 if the system has the type `unsigned long long int'. */ #undef HAVE_UNSIGNED_LONG_LONG_INT +/* Define to 1 if you have the `uselocale' function. */ +#undef HAVE_USELOCALE + /* Define to 1 if you have the `utime' function. */ #undef HAVE_UTIME diff --git a/src/include/pg_config.h.win32 b/src/include/pg_config.h.win32 index 8a560ef0f3..396443386a 100644 --- a/src/include/pg_config.h.win32 +++ b/src/include/pg_config.h.win32 @@ -545,6 +545,9 @@ /* Define to 1 if you have the `unsetenv' function. */ /* #undef HAVE_UNSETENV */ +/* Define to 1 if you have the `uselocale' function. */ +/* #undef HAVE_USELOCALE */ + /* Define to 1 if you have the `utime' function. */ #define HAVE_UTIME 1 diff --git a/src/interfaces/ecpg/ecpglib/descriptor.c b/src/interfaces/ecpg/ecpglib/descriptor.c index 186f92cc3e..71cef15172 100644 --- a/src/interfaces/ecpg/ecpglib/descriptor.c +++ b/src/interfaces/ecpg/ecpglib/descriptor.c @@ -483,22 +483,45 @@ ECPGget_desc(int lineno, const char *desc_name, int index,...) if (data_var.type != ECPGt_EORT) { struct statement stmt; - char *oldlocale; + + memset(&stmt, 0, sizeof stmt); + stmt.lineno = lineno; /* Make sure we do NOT honor the locale for numeric input */ /* since the database gives the standard decimal point */ - oldlocale = ecpg_strdup(setlocale(LC_NUMERIC, NULL), lineno); + /* (see comments in execute.c) */ +#ifdef HAVE_USELOCALE + stmt.clocale = newlocale(LC_NUMERIC_MASK, "C", (locale_t) 0); + if (stmt.clocale != (locale_t) 0) + stmt.oldlocale = uselocale(stmt.clocale); +#else +#ifdef WIN32 + stmt.oldthreadlocale = _configthreadlocale(_ENABLE_PER_THREAD_LOCALE); +#endif + stmt.oldlocale = ecpg_strdup(setlocale(LC_NUMERIC, NULL), lineno); setlocale(LC_NUMERIC, "C"); - - memset(&stmt, 0, sizeof stmt); - stmt.lineno = lineno; +#endif /* desperate try to guess something sensible */ stmt.connection = ecpg_get_connection(NULL); ecpg_store_result(ECPGresult, index, &stmt, &data_var); - setlocale(LC_NUMERIC, oldlocale); - ecpg_free(oldlocale); +#ifdef HAVE_USELOCALE + if (stmt.oldlocale != (locale_t) 0) + uselocale(stmt.oldlocale); + if (stmt.clocale) + freelocale(stmt.clocale); +#else + if (stmt.oldlocale) + { + setlocale(LC_NUMERIC, stmt.oldlocale); + ecpg_free(stmt.oldlocale); + } +#ifdef WIN32 + if (stmt.oldthreadlocale != -1) + _configthreadlocale(stmt.oldthreadlocale); +#endif +#endif } else if (data_var.ind_type != ECPGt_NO_INDICATOR && data_var.ind_pointer != NULL) diff --git a/src/interfaces/ecpg/ecpglib/ecpglib_extern.h b/src/interfaces/ecpg/ecpglib/ecpglib_extern.h index 1c9bce1456..41851d5900 100644 --- a/src/interfaces/ecpg/ecpglib/ecpglib_extern.h +++ b/src/interfaces/ecpg/ecpglib/ecpglib_extern.h @@ -12,6 +12,9 @@ #ifndef CHAR_BIT #include #endif +#ifdef LOCALE_T_IN_XLOCALE +#include +#endif enum COMPAT_MODE { @@ -61,7 +64,15 @@ struct statement bool questionmarks; struct variable *inlist; struct variable *outlist; +#ifdef HAVE_USELOCALE + locale_t clocale; + locale_t oldlocale; +#else char *oldlocale; +#ifdef WIN32 + int oldthreadlocale; +#endif +#endif int nparams; char **paramvalues; PGresult *results; diff --git a/src/interfaces/ecpg/ecpglib/execute.c b/src/interfaces/ecpg/ecpglib/execute.c index 3f5034e792..81aaf10f08 100644 --- a/src/interfaces/ecpg/ecpglib/execute.c +++ b/src/interfaces/ecpg/ecpglib/execute.c @@ -102,7 +102,12 @@ free_statement(struct statement *stmt) free_variable(stmt->outlist); ecpg_free(stmt->command); ecpg_free(stmt->name); +#ifdef HAVE_USELOCALE + if (stmt->clocale) + freelocale(stmt->clocale); +#else ecpg_free(stmt->oldlocale); +#endif ecpg_free(stmt); } @@ -1771,8 +1776,32 @@ ecpg_do_prologue(int lineno, const int compat, const int force_indicator, /* * Make sure we do NOT honor the locale for numeric input/output since the - * database wants the standard decimal point + * database wants the standard decimal point. If available, use + * uselocale() for this because it's thread-safe. Windows doesn't have + * that, but it does have _configthreadlocale(). */ +#ifdef HAVE_USELOCALE + stmt->clocale = newlocale(LC_NUMERIC_MASK, "C", (locale_t) 0); + if (stmt->clocale == (locale_t) 0) + { + ecpg_do_epilogue(stmt); + return false; + } + stmt->oldlocale = uselocale(stmt->clocale); + if (stmt->oldlocale == (locale_t) 0) + { + ecpg_do_epilogue(stmt); + return false; + } +#else +#ifdef WIN32 + stmt->oldthreadlocale = _configthreadlocale(_ENABLE_PER_THREAD_LOCALE); + if (stmt->oldthreadlocale == -1) + { + ecpg_do_epilogue(stmt); + return false; + } +#endif stmt->oldlocale = ecpg_strdup(setlocale(LC_NUMERIC, NULL), lineno); if (stmt->oldlocale == NULL) { @@ -1780,6 +1809,7 @@ ecpg_do_prologue(int lineno, const int compat, const int force_indicator, return false; } setlocale(LC_NUMERIC, "C"); +#endif #ifdef ENABLE_THREAD_SAFETY ecpg_pthreads_init(); @@ -1982,8 +2012,18 @@ ecpg_do_epilogue(struct statement *stmt) if (stmt == NULL) return; +#ifdef HAVE_USELOCALE + if (stmt->oldlocale != (locale_t) 0) + uselocale(stmt->oldlocale); +#else if (stmt->oldlocale) + { setlocale(LC_NUMERIC, stmt->oldlocale); +#ifdef WIN32 + _configthreadlocale(stmt->oldthreadlocale); +#endif + } +#endif free_statement(stmt); } -- 2.40.0