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/2065122.1609212051@sss.pgh.pa.us

1 files changed, 3 insertions, 28 deletions

diff --git a/src/backend/utils/adt/pg_locale.c b/src/backend/utils/adt/pg_locale.c
index c39d67645c6..088c1444c3b 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) != 0)
 		return NULL;
 
 	return result;