Use setenv() in preference to putenv().

Since at least 2001 we've used putenv() and avoided setenv(), on the
grounds that the latter was unportable and not in POSIX.  However,
POSIX added it that same year, and by now the situation has reversed:
setenv() is probably more portable than putenv(), since POSIX now
treats the latter as not being a core function.  And setenv() has
cleaner semantics too.  So, let's reverse that old policy.

This commit adds a simple src/port/ implementation of setenv() for
any stragglers (we have one in the buildfarm, but I'd not be surprised
if that code is never used in the field).  More importantly, extend
win32env.c to also support setenv().  Then, replace usages of putenv()
with setenv(), and get rid of some ad-hoc implementations of setenv()
wannabees.

Also, adjust our src/port/ implementation of unsetenv() to follow the
POSIX spec that it returns an error indicator, rather than returning
void as per the ancient BSD convention.  I don't feel a need to make
all the call sites check for errors, but the portability stub ought
to match real-world practice.

Discussion: https://postgr.es/m/[email protected]

Author: tglsfdc

configure

@@ -15959,12 +15959,29 @@ case $host_os in
         # Windows uses a specialised env handler
         mingw*)
 
+$as_echo "#define HAVE_SETENV 1" >>confdefs.h
+
+
 $as_echo "#define HAVE_UNSETENV 1" >>confdefs.h
 
+                ac_cv_func_setenv=yes
                 ac_cv_func_unsetenv=yes
                 ;;
         *)
-                ac_fn_c_check_func "$LINENO" "unsetenv" "ac_cv_func_unsetenv"
+                ac_fn_c_check_func "$LINENO" "setenv" "ac_cv_func_setenv"
+if test "x$ac_cv_func_setenv" = xyes; then :
+  $as_echo "#define HAVE_SETENV 1" >>confdefs.h
+
+else
+  case " $LIBOBJS " in
+  *" setenv.$ac_objext "* ) ;;
+  *) LIBOBJS="$LIBOBJS setenv.$ac_objext"
+ ;;
+esac
+
+fi
+
+ac_fn_c_check_func "$LINENO" "unsetenv" "ac_cv_func_unsetenv"
 if test "x$ac_cv_func_unsetenv" = xyes; then :
   $as_echo "#define HAVE_UNSETENV 1" >>confdefs.h
 

configure.ac

@@ -1757,11 +1757,13 @@ fi
 case $host_os in
         # Windows uses a specialised env handler
         mingw*)
+                AC_DEFINE(HAVE_SETENV, 1, [Define to 1 because replacement version used.])
                 AC_DEFINE(HAVE_UNSETENV, 1, [Define to 1 because replacement version used.])
+                ac_cv_func_setenv=yes
                 ac_cv_func_unsetenv=yes
                 ;;
         *)
-                AC_REPLACE_FUNCS([unsetenv])
+                AC_REPLACE_FUNCS([setenv unsetenv])
                 ;;
 esac
 

contrib/dblink/input/paths.source

@@ -1,8 +1,8 @@
 -- Initialization that requires path substitution.
 
-CREATE FUNCTION putenv(text)
+CREATE FUNCTION setenv(text, text)
    RETURNS void
-   AS '@libdir@/regress@DLSUFFIX@', 'regress_putenv'
+   AS '@libdir@/regress@DLSUFFIX@', 'regress_setenv'
    LANGUAGE C STRICT;
 
 CREATE FUNCTION wait_pid(int)
@@ -11,4 +11,4 @@ CREATE FUNCTION wait_pid(int)
    LANGUAGE C STRICT;
 
 CREATE FUNCTION set_pgservicefile(text) RETURNS void LANGUAGE SQL
-    AS $$SELECT putenv('PGSERVICEFILE=@abs_srcdir@/' || $1)$$;
+    AS $$SELECT setenv('PGSERVICEFILE', '@abs_srcdir@/' || $1)$$;

contrib/dblink/output/paths.source

@@ -1,11 +1,11 @@
 -- Initialization that requires path substitution.
-CREATE FUNCTION putenv(text)
+CREATE FUNCTION setenv(text, text)
    RETURNS void
-   AS '@libdir@/regress@DLSUFFIX@', 'regress_putenv'
+   AS '@libdir@/regress@DLSUFFIX@', 'regress_setenv'
    LANGUAGE C STRICT;
 CREATE FUNCTION wait_pid(int)
    RETURNS void
    AS '@libdir@/regress@DLSUFFIX@'
    LANGUAGE C STRICT;
 CREATE FUNCTION set_pgservicefile(text) RETURNS void LANGUAGE SQL
-    AS $$SELECT putenv('PGSERVICEFILE=@abs_srcdir@/' || $1)$$;
+    AS $$SELECT setenv('PGSERVICEFILE', '@abs_srcdir@/' || $1)$$;

src/backend/utils/adt/pg_locale.c

@@ -105,20 +105,6 @@ char	   *localized_full_months[12 + 1];
 static bool CurrentLocaleConvValid = false;
 static bool CurrentLCTimeValid = false;
 
-/* Environment variable storage area */
-
-#define LC_ENV_BUFSIZE (NAMEDATALEN + 20)
-
-static char lc_collate_envbuf[LC_ENV_BUFSIZE];
-static char lc_ctype_envbuf[LC_ENV_BUFSIZE];
-
-#ifdef LC_MESSAGES
-static char lc_messages_envbuf[LC_ENV_BUFSIZE];
-#endif
-static char lc_monetary_envbuf[LC_ENV_BUFSIZE];
-static char lc_numeric_envbuf[LC_ENV_BUFSIZE];
-static char lc_time_envbuf[LC_ENV_BUFSIZE];
-
 /* Cache for collation-related knowledge */
 
 typedef struct
@@ -163,7 +149,6 @@ pg_perm_setlocale(int category, const char *locale)
 {
 	char	   *result;
 	const char *envvar;
-	char	   *envbuf;
 
 #ifndef WIN32
 	result = setlocale(category, locale);
@@ -199,7 +184,7 @@ pg_perm_setlocale(int category, const char *locale)
 	 */
 	if (category == LC_CTYPE)
 	{
-		static char save_lc_ctype[LC_ENV_BUFSIZE];
+		static char save_lc_ctype[NAMEDATALEN + 20];
 
 		/* copy setlocale() return value before callee invokes it again */
 		strlcpy(save_lc_ctype, result, sizeof(save_lc_ctype));
@@ -216,16 +201,13 @@ pg_perm_setlocale(int category, const char *locale)
 	{
 		case LC_COLLATE:
 			envvar = "LC_COLLATE";
-			envbuf = lc_collate_envbuf;
 			break;
 		case LC_CTYPE:
 			envvar = "LC_CTYPE";
-			envbuf = lc_ctype_envbuf;
 			break;
 #ifdef LC_MESSAGES
 		case LC_MESSAGES:
 			envvar = "LC_MESSAGES";
-			envbuf = lc_messages_envbuf;
 #ifdef WIN32
 			result = IsoLocaleName(locale);
 			if (result == NULL)
@@ -236,26 +218,19 @@ pg_perm_setlocale(int category, const char *locale)
 #endif							/* LC_MESSAGES */
 		case LC_MONETARY:
 			envvar = "LC_MONETARY";
-			envbuf = lc_monetary_envbuf;
 			break;
 		case LC_NUMERIC:
 			envvar = "LC_NUMERIC";
-			envbuf = lc_numeric_envbuf;
 			break;
 		case LC_TIME:
 			envvar = "LC_TIME";
-			envbuf = lc_time_envbuf;
 			break;
 		default:
 			elog(FATAL, "unrecognized LC category: %d", category);
-			envvar = NULL;		/* keep compiler quiet */
-			envbuf = NULL;
-			return NULL;
+			return NULL;		/* keep compiler quiet */
 	}
 
-	snprintf(envbuf, LC_ENV_BUFSIZE - 1, "%s=%s", envvar, result);
-
-	if (putenv(envbuf))
+	if (setenv(envvar, result, 1) != 0)
 		return NULL;
 
 	return result;

src/bin/initdb/initdb.c

@@ -2355,8 +2355,7 @@ check_need_password(const char *authmethodlocal, const char *authmethodhost)
 void
 setup_pgdata(void)
 {
-	char	   *pgdata_get_env,
-			   *pgdata_set_env;
+	char	   *pgdata_get_env;
 
 	if (!pg_data)
 	{
@@ -2386,8 +2385,11 @@ setup_pgdata(void)
 	 * need quotes otherwise on Windows because paths there are most likely to
 	 * have embedded spaces.
 	 */
-	pgdata_set_env = psprintf("PGDATA=%s", pg_data);
-	putenv(pgdata_set_env);
+	if (setenv("PGDATA", pg_data, 1) != 0)
+	{
+		pg_log_error("could not set environment");
+		exit(1);
+	}
 }
 
 

src/bin/pg_ctl/pg_ctl.c

@@ -889,11 +889,10 @@ do_start(void)
 	 */
 #ifndef WIN32
 	{
-		static char env_var[32];
+		char		env_var[32];
 
-		snprintf(env_var, sizeof(env_var), "PG_GRANDPARENT_PID=%d",
-				 (int) getppid());
-		putenv(env_var);
+		snprintf(env_var, sizeof(env_var), "%d", (int) getppid());
+		setenv("PG_GRANDPARENT_PID", env_var, 1);
 	}
 #endif
 
@@ -2340,19 +2339,18 @@ main(int argc, char **argv)
 				case 'D':
 					{
 						char	   *pgdata_D;
-						char	   *env_var;
 
 						pgdata_D = pg_strdup(optarg);
 						canonicalize_path(pgdata_D);
-						env_var = psprintf("PGDATA=%s", pgdata_D);
-						putenv(env_var);
+						setenv("PGDATA", pgdata_D, 1);
 
 						/*
 						 * We could pass PGDATA just in an environment
 						 * variable but we do -D too for clearer postmaster
 						 * 'ps' display
 						 */
 						pgdata_opt = psprintf("-D \"%s\" ", pgdata_D);
+						free(pgdata_D);
 						break;
 					}
 				case 'e':

src/bin/pg_upgrade/controldata.c

@@ -97,20 +97,20 @@ get_control_data(ClusterInfo *cluster, bool live_check)
 	if (getenv("LC_MESSAGES"))
 		lc_messages = pg_strdup(getenv("LC_MESSAGES"));
 
-	pg_putenv("LC_COLLATE", NULL);
-	pg_putenv("LC_CTYPE", NULL);
-	pg_putenv("LC_MONETARY", NULL);
-	pg_putenv("LC_NUMERIC", NULL);
-	pg_putenv("LC_TIME", NULL);
+	unsetenv("LC_COLLATE");
+	unsetenv("LC_CTYPE");
+	unsetenv("LC_MONETARY");
+	unsetenv("LC_NUMERIC");
+	unsetenv("LC_TIME");
 #ifndef WIN32
-	pg_putenv("LANG", NULL);
+	unsetenv("LANG");
 #else
 	/* On Windows the default locale may not be English, so force it */
-	pg_putenv("LANG", "en");
+	setenv("LANG", "en", 1);
 #endif
-	pg_putenv("LANGUAGE", NULL);
-	pg_putenv("LC_ALL", NULL);
-	pg_putenv("LC_MESSAGES", "C");
+	unsetenv("LANGUAGE");
+	unsetenv("LC_ALL");
+	setenv("LC_MESSAGES", "C", 1);
 
 	/*
 	 * Check for clean shutdown
@@ -490,17 +490,31 @@ get_control_data(ClusterInfo *cluster, bool live_check)
 	pclose(output);
 
 	/*
-	 * Restore environment variables
+	 * Restore environment variables.  Note all but LANG and LC_MESSAGES were
+	 * unset above.
 	 */
-	pg_putenv("LC_COLLATE", lc_collate);
-	pg_putenv("LC_CTYPE", lc_ctype);
-	pg_putenv("LC_MONETARY", lc_monetary);
-	pg_putenv("LC_NUMERIC", lc_numeric);
-	pg_putenv("LC_TIME", lc_time);
-	pg_putenv("LANG", lang);
-	pg_putenv("LANGUAGE", language);
-	pg_putenv("LC_ALL", lc_all);
-	pg_putenv("LC_MESSAGES", lc_messages);
+	if (lc_collate)
+		setenv("LC_COLLATE", lc_collate, 1);
+	if (lc_ctype)
+		setenv("LC_CTYPE", lc_ctype, 1);
+	if (lc_monetary)
+		setenv("LC_MONETARY", lc_monetary, 1);
+	if (lc_numeric)
+		setenv("LC_NUMERIC", lc_numeric, 1);
+	if (lc_time)
+		setenv("LC_TIME", lc_time, 1);
+	if (lang)
+		setenv("LANG", lang, 1);
+	else
+		unsetenv("LANG");
+	if (language)
+		setenv("LANGUAGE", language, 1);
+	if (lc_all)
+		setenv("LC_ALL", lc_all, 1);
+	if (lc_messages)
+		setenv("LC_MESSAGES", lc_messages, 1);
+	else
+		unsetenv("LC_MESSAGES");
 
 	pg_free(lc_collate);
 	pg_free(lc_ctype);

src/bin/pg_upgrade/option.c

@@ -193,7 +193,7 @@ parseCommandLine(int argc, char *argv[])
 				 * Push the user name into the environment so pre-9.1
 				 * pg_ctl/libpq uses it.
 				 */
-				pg_putenv("PGUSER", os_info.user);
+				setenv("PGUSER", os_info.user, 1);
 				break;
 
 			case 'v':
@@ -245,11 +245,11 @@ parseCommandLine(int argc, char *argv[])
 		char	   *pgoptions = psprintf("%s %s", FIX_DEFAULT_READ_ONLY,
 										 getenv("PGOPTIONS"));
 
-		pg_putenv("PGOPTIONS", pgoptions);
+		setenv("PGOPTIONS", pgoptions, 1);
 		pfree(pgoptions);
 	}
 	else
-		pg_putenv("PGOPTIONS", FIX_DEFAULT_READ_ONLY);
+		setenv("PGOPTIONS", FIX_DEFAULT_READ_ONLY, 1);
 
 	/* Get values from env if not already set */
 	check_required_directory(&old_cluster.bindir, "PGBINOLD", false,

src/bin/pg_upgrade/pg_upgrade.h

@@ -436,7 +436,6 @@ void		end_progress_output(void);
 void		prep_status(const char *fmt,...) pg_attribute_printf(1, 2);
 void		check_ok(void);
 unsigned int str2uint(const char *str);
-void		pg_putenv(const char *var, const char *val);
 
 
 /* version.c */

src/bin/pg_upgrade/util.c

@@ -241,39 +241,3 @@ str2uint(const char *str)
 {
 	return strtoul(str, NULL, 10);
 }
-
-
-/*
- *	pg_putenv()
- *
- *	This is like putenv(), but takes two arguments.
- *	It also does unsetenv() if val is NULL.
- */
-void
-pg_putenv(const char *var, const char *val)
-{
-	if (val)
-	{
-#ifndef WIN32
-		char	   *envstr;
-
-		envstr = psprintf("%s=%s", var, val);
-		putenv(envstr);
-
-		/*
-		 * Do not free envstr because it becomes part of the environment on
-		 * some operating systems.  See port/unsetenv.c::unsetenv.
-		 */
-#else
-		SetEnvironmentVariableA(var, val);
-#endif
-	}
-	else
-	{
-#ifndef WIN32
-		unsetenv(var);
-#else
-		SetEnvironmentVariableA(var, "");
-#endif
-	}
-}

src/bin/psql/command.c

@@ -2296,17 +2296,8 @@ exec_command_setenv(PsqlScanState scan_state, bool active_branch,
 		else
 		{
 			/* Set variable to the value of the next argument */
-			char	   *newval;
-
-			newval = psprintf("%s=%s", envvar, envval);
-			putenv(newval);
+			setenv(envvar, envval, 1);
 			success = true;
-
-			/*
-			 * Do not free newval here, it will screw up the environment if
-			 * you do. See putenv man page for details. That means we leak a
-			 * bit of memory here, but not enough to worry about.
-			 */
 		}
 		free(envvar);
 		free(envval);