Change initdb and CREATE DATABASE to actively reject attempts to create

databases with encodings that are incompatible with the server's LC_CTYPE
locale, when we can determine that (which we can on most modern platforms,
I believe).  C/POSIX locale is compatible with all encodings, of course,
so there is still some usefulness to CREATE DATABASE's ENCODING option,
but this will insulate us against all sorts of recurring complaints
caused by mismatched settings.

I moved initdb's existing LC_CTYPE-to-encoding mapping knowledge into
a new src/port/ file so it could be shared by CREATE DATABASE.

1 files changed, 29 insertions, 1 deletions

diff --git a/src/backend/commands/dbcommands.c b/src/backend/commands/dbcommands.c
index f6274803622..094f51b5cc9 100644
--- a/src/backend/commands/dbcommands.c
+++ b/src/backend/commands/dbcommands.c
@@ -13,13 +13,14 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/commands/dbcommands.c,v 1.198 2007/09/03 18:46:29 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/commands/dbcommands.c,v 1.199 2007/09/28 22:25:49 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
 #include "postgres.h"
 
 #include <fcntl.h>
+#include <locale.h>
 #include <unistd.h>
 #include <sys/stat.h>
 
@@ -96,6 +97,7 @@ createdb(const CreatedbStmt *stmt)
 	const char *dbtemplate = NULL;
 	int			encoding = -1;
 	int			dbconnlimit = -1;
+	int			ctype_encoding;
 
 	/* Extract options from the statement node tree */
 	foreach(option, stmt->options)
@@ -254,6 +256,32 @@ createdb(const CreatedbStmt *stmt)
 				(errcode(ERRCODE_WRONG_OBJECT_TYPE),
 				 errmsg("invalid server encoding %d", encoding)));
 
+	/*
+	 * Check whether encoding matches server locale settings.  We allow
+	 * mismatch in two cases:
+	 *
+	 * 1. ctype_encoding = SQL_ASCII, which means either that the locale
+	 * is C/POSIX which works with any encoding, or that we couldn't determine
+	 * the locale's encoding and have to trust the user to get it right.
+	 *
+	 * 2. selected encoding is SQL_ASCII, but only if you're a superuser.
+	 * This is risky but we have historically allowed it --- notably, the
+	 * regression tests require it.
+	 *
+	 * Note: if you change this policy, fix initdb to match.
+	 */
+	ctype_encoding = pg_get_encoding_from_locale(NULL);
+
+	if (!(ctype_encoding == encoding ||
+		  ctype_encoding == PG_SQL_ASCII ||
+		  (encoding == PG_SQL_ASCII && superuser())))
+		ereport(ERROR,
+				(errmsg("encoding %s does not match server's locale %s",
+						pg_encoding_to_char(encoding),
+						setlocale(LC_CTYPE, NULL)),
+				 errdetail("The server's LC_CTYPE setting requires encoding %s.",
+						   pg_encoding_to_char(ctype_encoding))));
+
 	/* Resolve default tablespace for new database */
 	if (dtablespacename && dtablespacename->arg)
 	{