From 5b94e2bd4d5430f5ea4e965a32727a6006972a55 Mon Sep 17 00:00:00 2001 From: Noah Misch Date: Sat, 2 Jul 2022 13:00:30 -0700 Subject: [PATCH] ecpglib: call newlocale() once per process. ecpglib has been calling it once per SQL query and once per EXEC SQL GET DESCRIPTOR. Instead, if newlocale() has not succeeded before, call it while establishing a connection. This mitigates three problems: - If newlocale() failed in EXEC SQL GET DESCRIPTOR, the command silently proceeded without the intended locale change. - On AIX, each newlocale()+freelocale() cycle leaked memory. - newlocale() CPU usage may have been nontrivial. Fail the connection attempt if newlocale() fails. Rearrange ecpg_do_prologue() to validate the connection before its uselocale(). The sort of program that may regress is one running in an environment where newlocale() fails. If that program establishes connections without running SQL statements, it will stop working in response to this change. I'm betting against the importance of such an ECPG use case. Most SQL execution (any using ECPGdo()) has long required newlocale() success, so there's little a connection could do without newlocale(). Back-patch to v10 (all supported versions). Reviewed by Tom Lane. Reported by Guillaume Lelarge. Discussion: https://postgr.es/m/20220101074055.GA54621@rfd.leadboat.com --- src/interfaces/ecpg/ecpglib/connect.c | 40 ++++++++++++++++++++ src/interfaces/ecpg/ecpglib/descriptor.c | 15 +++++--- src/interfaces/ecpg/ecpglib/ecpglib_extern.h | 5 ++- src/interfaces/ecpg/ecpglib/execute.c | 40 +++++++++----------- 4 files changed, 71 insertions(+), 29 deletions(-) diff --git a/src/interfaces/ecpg/ecpglib/connect.c b/src/interfaces/ecpg/ecpglib/connect.c index 15e6bbe36b..262d5042f9 100644 --- a/src/interfaces/ecpg/ecpglib/connect.c +++ b/src/interfaces/ecpg/ecpglib/connect.c @@ -10,6 +10,10 @@ #include "ecpgtype.h" #include "sqlca.h" +#ifdef HAVE_USELOCALE +locale_t ecpg_clocale; +#endif + #ifdef ENABLE_THREAD_SAFETY static pthread_mutex_t connections_mutex = PTHREAD_MUTEX_INITIALIZER; static pthread_key_t actual_connection_key; @@ -505,6 +509,42 @@ ECPGconnect(int lineno, int c, const char *name, const char *user, const char *p #ifdef ENABLE_THREAD_SAFETY pthread_mutex_lock(&connections_mutex); #endif + + /* + * ... but first, make certain we have created ecpg_clocale. Rely on + * holding connections_mutex to ensure this is done by only one thread. + */ +#ifdef HAVE_USELOCALE + if (!ecpg_clocale) + { + ecpg_clocale = newlocale(LC_NUMERIC_MASK, "C", (locale_t) 0); + if (!ecpg_clocale) + { +#ifdef ENABLE_THREAD_SAFETY + pthread_mutex_unlock(&connections_mutex); +#endif + ecpg_raise(lineno, ECPG_OUT_OF_MEMORY, + ECPG_SQLSTATE_ECPG_OUT_OF_MEMORY, NULL); + if (host) + ecpg_free(host); + if (port) + ecpg_free(port); + if (options) + ecpg_free(options); + if (realname) + ecpg_free(realname); + if (dbname) + ecpg_free(dbname); + if (conn_keywords) + ecpg_free(conn_keywords); + if (conn_values) + ecpg_free(conn_values); + free(this); + return false; + } + } +#endif + if (connection_name != NULL) this->name = ecpg_strdup(connection_name, lineno); else diff --git a/src/interfaces/ecpg/ecpglib/descriptor.c b/src/interfaces/ecpg/ecpglib/descriptor.c index 369c2f0867..f1898dec6a 100644 --- a/src/interfaces/ecpg/ecpglib/descriptor.c +++ b/src/interfaces/ecpg/ecpglib/descriptor.c @@ -486,9 +486,16 @@ ECPGget_desc(int lineno, const char *desc_name, int index,...) /* since the database gives the standard decimal point */ /* (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); + + /* + * To get here, the above PQnfields() test must have found nonzero + * fields. One needs a connection to create such a descriptor. (EXEC + * SQL SET DESCRIPTOR can populate the descriptor's "items", but it + * can't change the descriptor's PQnfields().) Any successful + * connection initializes ecpg_clocale. + */ + Assert(ecpg_clocale); + stmt.oldlocale = uselocale(ecpg_clocale); #else #ifdef HAVE__CONFIGTHREADLOCALE stmt.oldthreadlocale = _configthreadlocale(_ENABLE_PER_THREAD_LOCALE); @@ -504,8 +511,6 @@ ECPGget_desc(int lineno, const char *desc_name, int index,...) #ifdef HAVE_USELOCALE if (stmt.oldlocale != (locale_t) 0) uselocale(stmt.oldlocale); - if (stmt.clocale) - freelocale(stmt.clocale); #else if (stmt.oldlocale) { diff --git a/src/interfaces/ecpg/ecpglib/ecpglib_extern.h b/src/interfaces/ecpg/ecpglib/ecpglib_extern.h index 1a98dea1b5..c438cfb820 100644 --- a/src/interfaces/ecpg/ecpglib/ecpglib_extern.h +++ b/src/interfaces/ecpg/ecpglib/ecpglib_extern.h @@ -59,6 +59,10 @@ struct ECPGtype_information_cache enum ARRAY_TYPE isarray; }; +#ifdef HAVE_USELOCALE +extern locale_t ecpg_clocale; /* LC_NUMERIC=C */ +#endif + /* structure to store one statement */ struct statement { @@ -73,7 +77,6 @@ struct statement struct variable *inlist; struct variable *outlist; #ifdef HAVE_USELOCALE - locale_t clocale; locale_t oldlocale; #else char *oldlocale; diff --git a/src/interfaces/ecpg/ecpglib/execute.c b/src/interfaces/ecpg/ecpglib/execute.c index 930b6adbe4..e8e8fb2b2c 100644 --- a/src/interfaces/ecpg/ecpglib/execute.c +++ b/src/interfaces/ecpg/ecpglib/execute.c @@ -101,10 +101,7 @@ 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 +#ifndef HAVE_USELOCALE ecpg_free(stmt->oldlocale); #endif ecpg_free(stmt); @@ -1966,6 +1963,15 @@ ecpg_do_prologue(int lineno, const int compat, const int force_indicator, return false; } +#ifdef ENABLE_THREAD_SAFETY + ecpg_pthreads_init(); +#endif + + con = ecpg_get_connection(connection_name); + + if (!ecpg_init(con, connection_name, lineno)) + return false; + stmt = (struct statement *) ecpg_alloc(sizeof(struct statement), lineno); if (stmt == NULL) @@ -1980,13 +1986,13 @@ ecpg_do_prologue(int lineno, const int compat, const int force_indicator, * treat that situation as if the function doesn't exist. */ #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); + + /* + * Since ecpg_init() succeeded, we have a connection. Any successful + * connection initializes ecpg_clocale. + */ + Assert(ecpg_clocale); + stmt->oldlocale = uselocale(ecpg_clocale); if (stmt->oldlocale == (locale_t) 0) { ecpg_do_epilogue(stmt); @@ -2005,18 +2011,6 @@ ecpg_do_prologue(int lineno, const int compat, const int force_indicator, setlocale(LC_NUMERIC, "C"); #endif -#ifdef ENABLE_THREAD_SAFETY - ecpg_pthreads_init(); -#endif - - con = ecpg_get_connection(connection_name); - - if (!ecpg_init(con, connection_name, lineno)) - { - ecpg_do_epilogue(stmt); - return false; - } - /* * If statement type is ECPGst_prepnormal we are supposed to prepare the * statement before executing them