Doh --- what's really happening on buildfarm member grebe is that its

tglsfdc · tglsfdc · commit 94470b949967 · 2007-09-22T04:37:53.000Z
malloc returns NULL for malloc(0).  Defend against that case.
diff --git a/src/backend/utils/adt/regexp.c b/src/backend/utils/adt/regexp.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/regexp.c,v 1.74 2007/09/21 22:52:52 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/regexp.c,v 1.75 2007/09/22 04:37:53 tgl Exp $
  *
  *		Alistair Crooks added the code for the regex caching
  *		agc - cached the regular expressions used - there's a good chance
@@ -195,10 +195,12 @@ RE_compile_and_cache(text *text_re, int cflags)
 	}
 
 	/*
-	 * use malloc/free for the cre_pat field because the storage has to
-	 * persist across transactions
+	 * We use malloc/free for the cre_pat field because the storage has to
+	 * persist across transactions, and because we want to get control back
+	 * on out-of-memory.  The Max() is because some malloc implementations
+	 * return NULL for malloc(0).
 	 */
-	re_temp.cre_pat = malloc(text_re_len);
+	re_temp.cre_pat = malloc(Max(text_re_len, 1));
 	if (re_temp.cre_pat == NULL)
 	{
 		pg_regfree(&re_temp.cre_re);

Original file line number	Diff line number	Diff line change
`@@ -8,7 +8,7 @@`
`8`	`8`	`*`
`9`	`9`	`*`
`10`	`10`	`* IDENTIFICATION`
`11`		`- * $PostgreSQL: pgsql/src/backend/utils/adt/regexp.c,v 1.74 2007/09/21 22:52:52 tgl Exp $`
	`11`	`+ * $PostgreSQL: pgsql/src/backend/utils/adt/regexp.c,v 1.75 2007/09/22 04:37:53 tgl Exp $`
`12`	`12`	`*`
`13`	`13`	`* Alistair Crooks added the code for the regex caching`
`14`	`14`	`* agc - cached the regular expressions used - there's a good chance`
`@@ -195,10 +195,12 @@ RE_compile_and_cache(text *text_re, int cflags)`
`195`	`195`	`}`
`196`	`196`
`197`	`197`	`/*`
`198`		`- * use malloc/free for the cre_pat field because the storage has to`
`199`		`- * persist across transactions`
	`198`	`+ * We use malloc/free for the cre_pat field because the storage has to`
	`199`	`+ * persist across transactions, and because we want to get control back`
	`200`	`+ * on out-of-memory. The Max() is because some malloc implementations`
	`201`	`+ * return NULL for malloc(0).`
`200`	`202`	`*/`
`201`		`- re_temp.cre_pat = malloc(text_re_len);`
	`203`	`+ re_temp.cre_pat = malloc(Max(text_re_len, 1));`
`202`	`204`	`if (re_temp.cre_pat == NULL)`
`203`	`205`	`{`
`204`	`206`	`pg_regfree(&re_temp.cre_re);`