support-using-setenv-1.patch

diff --git a/configure b/configure
index 11a4284e5b..07529825d1 100755
--- a/configure
+++ b/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
 
diff --git a/configure.ac b/configure.ac
index fc523c6aeb..7f855783f4 100644
--- a/configure.ac
+++ b/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
 
diff --git a/src/backend/libpq/auth.c b/src/backend/libpq/auth.c
index 515ae95fe1..64d6e85555 100644
--- a/src/backend/libpq/auth.c
+++ b/src/backend/libpq/auth.c
@@ -1059,24 +1059,16 @@ pg_GSS_recvauth(Port *port)
 		/*
 		 * Set default Kerberos keytab file for the Krb5 mechanism.
 		 *
-		 * setenv("KRB5_KTNAME", pg_krb_server_keyfile, 0); except setenv()
-		 * not always available.
+		 * We don't overwrite any existing environment variable ... is that
+		 * really a sane choice?
 		 */
-		if (getenv("KRB5_KTNAME") == NULL)
+		if (setenv("KRB5_KTNAME", pg_krb_server_keyfile, 0) != 0)
 		{
-			size_t		kt_len = strlen(pg_krb_server_keyfile) + 14;
-			char	   *kt_path = malloc(kt_len);
-
-			if (!kt_path ||
-				snprintf(kt_path, kt_len, "KRB5_KTNAME=%s",
-						 pg_krb_server_keyfile) != kt_len - 2 ||
-				putenv(kt_path) != 0)
-			{
-				ereport(LOG,
-						(errcode(ERRCODE_OUT_OF_MEMORY),
-						 errmsg("out of memory")));
-				return STATUS_ERROR;
-			}
+			/* We assume the error must be "out of memory" */
+			ereport(LOG,
+					(errcode(ERRCODE_OUT_OF_MEMORY),
+					 errmsg("out of memory")));
+			return STATUS_ERROR;
 		}
 	}
 
diff --git a/src/backend/utils/adt/pg_locale.c b/src/backend/utils/adt/pg_locale.c
index c39d67645c..148a0984ea 100644
--- a/src/backend/utils/adt/pg_locale.c
+++ b/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))
 		return NULL;
 
 	return result;
diff --git a/src/bin/initdb/initdb.c b/src/bin/initdb/initdb.c
index f994c4216b..523d55dc65 100644
--- a/src/bin/initdb/initdb.c
+++ b/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("setenv failed");
+		exit(1);
+	}
 }
 
 
diff --git a/src/include/pg_config.h.in b/src/include/pg_config.h.in
index de8f838e53..ddaa9e8e18 100644
--- a/src/include/pg_config.h.in
+++ b/src/include/pg_config.h.in
@@ -473,6 +473,9 @@
 /* Define to 1 if you have the <security/pam_appl.h> header file. */
 #undef HAVE_SECURITY_PAM_APPL_H
 
+/* Define to 1 if you have the `setenv' function. */
+#undef HAVE_SETENV
+
 /* Define to 1 if you have the `setproctitle' function. */
 #undef HAVE_SETPROCTITLE
 
diff --git a/src/include/port.h b/src/include/port.h
index 5dfb00b07c..c631185c8b 100644
--- a/src/include/port.h
+++ b/src/include/port.h
@@ -447,8 +447,12 @@ extern size_t strnlen(const char *str, size_t maxlen);
 extern long random(void);
 #endif
 
+#ifndef HAVE_SETENV
+extern int	setenv(const char *name, const char *value, int overwrite);
+#endif
+
 #ifndef HAVE_UNSETENV
-extern void unsetenv(const char *name);
+extern int	unsetenv(const char *name);
 #endif
 
 #ifndef HAVE_SRANDOM
diff --git a/src/include/port/win32_port.h b/src/include/port/win32_port.h
index 59c7f35e3d..2ffe056a0f 100644
--- a/src/include/port/win32_port.h
+++ b/src/include/port/win32_port.h
@@ -490,7 +490,12 @@ extern void _dosmaperr(unsigned long);
 
 /* in port/win32env.c */
 extern int	pgwin32_putenv(const char *);
-extern void pgwin32_unsetenv(const char *);
+extern int	pgwin32_setenv(const char *name, const char *value, int overwrite);
+extern int	pgwin32_unsetenv(const char *name);
+
+#define putenv(x) pgwin32_putenv(x)
+#define setenv(x,y,z) pgwin32_setenv(x,y,z)
+#define unsetenv(x) pgwin32_unsetenv(x)
 
 /* in port/win32security.c */
 extern int	pgwin32_is_service(void);
@@ -499,9 +504,6 @@ extern int	pgwin32_is_admin(void);
 /* Windows security token manipulation (in src/common/exec.c) */
 extern BOOL AddUserToTokenDacl(HANDLE hToken);
 
-#define putenv(x) pgwin32_putenv(x)
-#define unsetenv(x) pgwin32_unsetenv(x)
-
 /* Things that exist in MinGW headers, but need to be added to MSVC */
 #ifdef _MSC_VER
 
diff --git a/src/port/setenv.c b/src/port/setenv.c
new file mode 100644
index 0000000000..d8a5647fb0
--- /dev/null
+++ b/src/port/setenv.c
@@ -0,0 +1,48 @@
+/*-------------------------------------------------------------------------
+ *
+ * setenv.c
+ *	  setenv() emulation for machines without it
+ *
+ * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
+ * Portions Copyright (c) 1994, Regents of the University of California
+ *
+ *
+ * IDENTIFICATION
+ *	  src/port/setenv.c
+ *
+ *-------------------------------------------------------------------------
+ */
+
+#include "c.h"
+
+
+int
+setenv(const char *name, const char *value, int overwrite)
+{
+	char	   *envstr;
+
+	/* Error conditions, per POSIX */
+	if (name == NULL || name[0] == '\0' || strchr(name, '=') != NULL ||
+		value == NULL)
+	{
+		errno = EINVAL;
+		return -1;
+	}
+
+	/* No work if variable exists and we're not to replace it */
+	if (overwrite == 0 && getenv(name) != NULL)
+		return 0;
+
+	/*
+	 * Add or replace the value using putenv().  This will leak memory if the
+	 * same variable is repeatedly redefined, but there's little we can do
+	 * about that when sitting atop putenv().
+	 */
+	envstr = (char *) malloc(strlen(name) + strlen(value) + 2);
+	if (!envstr)				/* not much we can do if no memory */
+		return -1;
+
+	sprintf(envstr, "%s=%s", name, value);
+
+	return putenv(envstr);
+}
diff --git a/src/port/unsetenv.c b/src/port/unsetenv.c
index f2028c2f83..a5f19f8db3 100644
--- a/src/port/unsetenv.c
+++ b/src/port/unsetenv.c
@@ -16,13 +16,20 @@
 #include "c.h"
 
 
-void
+int
 unsetenv(const char *name)
 {
 	char	   *envstr;
 
+	/* Error conditions, per POSIX */
+	if (name == NULL || name[0] == '\0' || strchr(name, '=') != NULL)
+	{
+		errno = EINVAL;
+		return -1;
+	}
+
 	if (getenv(name) == NULL)
-		return;					/* no work */
+		return 0;				/* no work */
 
 	/*
 	 * The technique embodied here works if libc follows the Single Unix Spec
@@ -40,11 +47,12 @@ unsetenv(const char *name)
 
 	envstr = (char *) malloc(strlen(name) + 2);
 	if (!envstr)				/* not much we can do if no memory */
-		return;
+		return -1;
 
 	/* Override the existing setting by forcibly defining the var */
 	sprintf(envstr, "%s=", name);
-	putenv(envstr);
+	if (putenv(envstr))
+		return -1;
 
 	/* Now we can clobber the variable definition this way: */
 	strcpy(envstr, "=");
@@ -53,5 +61,5 @@ unsetenv(const char *name)
 	 * This last putenv cleans up if we have multiple zero-length names as a
 	 * result of unsetting multiple things.
 	 */
-	putenv(envstr);
+	return putenv(envstr);
 }
diff --git a/src/port/win32env.c b/src/port/win32env.c
index 177488cc67..f5bed67297 100644
--- a/src/port/win32env.c
+++ b/src/port/win32env.c
@@ -1,8 +1,10 @@
 /*-------------------------------------------------------------------------
  *
  * win32env.c
- *	  putenv() and unsetenv() for win32, which update both process environment
- *	  and caches in (potentially multiple) C run-time library (CRT) versions.
+ *	  putenv(), setenv(), and unsetenv() for win32.
+ *
+ * These functions update both the process environment and caches in
+ * (potentially multiple) C run-time library (CRT) versions.
  *
  * Portions Copyright (c) 1996-2020, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
@@ -16,6 +18,11 @@
 
 #include "c.h"
 
+
+/*
+ * Note that unlike POSIX putenv(), this doesn't use the passed-in string
+ * as permanent storage.
+ */
 int
 pgwin32_putenv(const char *envval)
 {
@@ -64,7 +71,7 @@ pgwin32_putenv(const char *envval)
 	}
 	*cp = '\0';
 	cp++;
-	if (strlen(cp))
+	if (*cp)
 	{
 		/*
 		 * Only call SetEnvironmentVariable() when we are adding a variable,
@@ -110,16 +117,47 @@ pgwin32_putenv(const char *envval)
 	return _putenv(envval);
 }
 
-void
+int
+pgwin32_setenv(const char *name, const char *value, int overwrite)
+{
+	int			res;
+	char	   *envstr;
+
+	/* Error conditions, per POSIX */
+	if (name == NULL || name[0] == '\0' || strchr(name, '=') != NULL ||
+		value == NULL)
+	{
+		errno = EINVAL;
+		return -1;
+	}
+
+	/* No work if variable exists and we're not to replace it */
+	if (overwrite == 0 && getenv(name) != NULL)
+		return 0;
+
+	envstr = (char *) malloc(strlen(name) + strlen(value) + 2);
+	if (!envstr)				/* not much we can do if no memory */
+		return -1;
+
+	sprintf(envstr, "%s=%s", name, value);
+
+	res = pgwin32_putenv(envstr);
+	free(envstr);
+	return res;
+}
+
+int
 pgwin32_unsetenv(const char *name)
 {
+	int			res;
 	char	   *envbuf;
 
 	envbuf = (char *) malloc(strlen(name) + 2);
 	if (!envbuf)
-		return;
+		return -1;
 
 	sprintf(envbuf, "%s=", name);
-	pgwin32_putenv(envbuf);
+	res = pgwin32_putenv(envbuf);
 	free(envbuf);
+	return res;
 }
diff --git a/src/tools/msvc/Solution.pm b/src/tools/msvc/Solution.pm
index 22d6abd367..95d4e826b1 100644
--- a/src/tools/msvc/Solution.pm
+++ b/src/tools/msvc/Solution.pm
@@ -348,6 +348,7 @@ sub GenerateFiles
 		HAVE_RL_FILENAME_QUOTING_FUNCTION        => undef,
 		HAVE_RL_RESET_SCREEN_SIZE                => undef,
 		HAVE_SECURITY_PAM_APPL_H                 => undef,
+		HAVE_SETENV                              => undef,
 		HAVE_SETPROCTITLE                        => undef,
 		HAVE_SETPROCTITLE_FAST                   => undef,
 		HAVE_SETSID                              => undef,