From: Noah Misch <noah@leadboat.com>
Date: Sun, 12 Nov 2017 21:03:15 +0000 (-0800)
Subject: Don't call pgwin32_message_to_UTF16() without CurrentMemoryContext.
X-Git-Tag: REL9_6_7~77
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=fd5da32fc62f96952a54696f8ab2ce913fe19bc0;p=postgresql

Don't call pgwin32_message_to_UTF16() without CurrentMemoryContext.

PostgreSQL running as a Windows service crashed upon calling
write_stderr() before MemoryContextInit().  This fix completes work
started in 5735efee15540765315aa8c1a230575e756037f7.  Messages this
early contain only ASCII bytes; if we removed the CurrentMemoryContext
requirement, the ensuing conversions would have no effect.  Back-patch
to 9.3 (all supported versions).

Takayuki Tsunakawa, reviewed by Michael Paquier.

Discussion: https://postgr.es/m/0A3221C70F24FB45833433255569204D1F80CC73@G01JPEXMBYT05
---

diff --git a/src/backend/utils/error/elog.c b/src/backend/utils/error/elog.c
index eace0ac100..7e977e8b18 100644
--- a/src/backend/utils/error/elog.c
+++ b/src/backend/utils/error/elog.c
@@ -2117,10 +2117,15 @@ write_eventlog(int level, const char *line, int len)
 	 * try to convert the message to UTF16 and write it with ReportEventW().
 	 * Fall back on ReportEventA() if conversion failed.
 	 *
+	 * Since we palloc the structure required for conversion, also fall
+	 * through to writing unconverted if we have not yet set up
+	 * CurrentMemoryContext.
+	 *
 	 * Also verify that we are not on our way into error recursion trouble due
 	 * to error messages thrown deep inside pgwin32_message_to_UTF16().
 	 */
 	if (!in_error_recursion_trouble() &&
+		CurrentMemoryContext != NULL &&
 		GetMessageEncoding() != GetACPEncoding())
 	{
 		utf16 = pgwin32_message_to_UTF16(line, len, NULL);
diff --git a/src/backend/utils/mb/mbutils.c b/src/backend/utils/mb/mbutils.c
index 7f1c881cce..4dcb833d83 100644
--- a/src/backend/utils/mb/mbutils.c
+++ b/src/backend/utils/mb/mbutils.c
@@ -1049,8 +1049,10 @@ GetMessageEncoding(void)
 
 #ifdef WIN32
 /*
- * Result is palloc'ed null-terminated utf16 string. The character length
- * is also passed to utf16len if not null. Returns NULL iff failed.
+ * Convert from MessageEncoding to a palloc'ed, null-terminated utf16
+ * string. The character length is also passed to utf16len if not
+ * null. Returns NULL iff failed. Before MessageEncoding initialization, "str"
+ * should be ASCII-only; this will function as though MessageEncoding is UTF8.
  */
 WCHAR *
 pgwin32_message_to_UTF16(const char *str, int len, int *utf16len)