Prevent memory leaks in our various bison parsers when an error occurs

during parsing.  Formerly the parser's stack was allocated with malloc
and so wouldn't be reclaimed; this patch makes it use palloc instead,
so that flushing the current context will reclaim the memory.  Per
Marko Kreen.

5 files changed, 56 insertions, 0 deletions

diff --git a/contrib/cube/cubeparse.y b/contrib/cube/cubeparse.y
index 26a97810fa..6b96da5127 100644
--- a/contrib/cube/cubeparse.y
+++ b/contrib/cube/cubeparse.y
@@ -12,6 +12,17 @@
 
 #include "cubedata.h"
 
+/*
+ * Bison doesn't allocate anything that needs to live across parser calls,
+ * so we can easily have it use palloc instead of malloc.  This prevents
+ * memory leaks if we error out during parsing.  Note this only works with
+ * bison >= 2.0.  However, in bison 1.875 the default is to use alloca()
+ * if possible, so there's not really much problem anyhow, at least if
+ * you're building with gcc.
+ */
+#define YYMALLOC palloc
+#define YYFREE   pfree
+
 extern int cube_yylex(void);
 
 static char *scanbuf;
diff --git a/contrib/seg/segparse.y b/contrib/seg/segparse.y
index dc56fb580f..47e3d398aa 100644
--- a/contrib/seg/segparse.y
+++ b/contrib/seg/segparse.y
@@ -9,6 +9,17 @@
 #include "utils/builtins.h"
 #include "segdata.h"
 
+/*
+ * Bison doesn't allocate anything that needs to live across parser calls,
+ * so we can easily have it use palloc instead of malloc.  This prevents
+ * memory leaks if we error out during parsing.  Note this only works with
+ * bison >= 2.0.  However, in bison 1.875 the default is to use alloca()
+ * if possible, so there's not really much problem anyhow, at least if
+ * you're building with gcc.
+ */
+#define YYMALLOC palloc
+#define YYFREE   pfree
+
   extern int seg_yylex(void);
 
   extern int significant_digits(char *str);		/* defined in seg.c */
diff --git a/src/backend/bootstrap/bootparse.y b/src/backend/bootstrap/bootparse.y
index e89f718b8e..38971e0d98 100644
--- a/src/backend/bootstrap/bootparse.y
+++ b/src/backend/bootstrap/bootparse.y
@@ -54,6 +54,17 @@
 #define atooid(x)	((Oid) strtoul((x), NULL, 10))
 
 
+/*
+ * Bison doesn't allocate anything that needs to live across parser calls,
+ * so we can easily have it use palloc instead of malloc.  This prevents
+ * memory leaks if we error out during parsing.  Note this only works with
+ * bison >= 2.0.  However, in bison 1.875 the default is to use alloca()
+ * if possible, so there's not really much problem anyhow, at least if
+ * you're building with gcc.
+ */
+#define YYMALLOC palloc
+#define YYFREE   pfree
+
 static void
 do_start(void)
 {
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 0b70ba007c..e9b45a400e 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -79,6 +79,17 @@
  */
 #define base_yylex filtered_base_yylex
 
+/*
+ * Bison doesn't allocate anything that needs to live across parser calls,
+ * so we can easily have it use palloc instead of malloc.  This prevents
+ * memory leaks if we error out during parsing.  Note this only works with
+ * bison >= 2.0.  However, in bison 1.875 the default is to use alloca()
+ * if possible, so there's not really much problem anyhow, at least if
+ * you're building with gcc.
+ */
+#define YYMALLOC palloc
+#define YYFREE   pfree
+
 extern List *parsetree;			/* final parse result is delivered here */
 
 static bool QueryIsRule = FALSE;
diff --git a/src/pl/plpgsql/src/gram.y b/src/pl/plpgsql/src/gram.y
index 075d66367a..e6f806b066 100644
--- a/src/pl/plpgsql/src/gram.y
+++ b/src/pl/plpgsql/src/gram.y
@@ -19,6 +19,18 @@
 #include "parser/parser.h"
 
 
+/*
+ * Bison doesn't allocate anything that needs to live across parser calls,
+ * so we can easily have it use palloc instead of malloc.  This prevents
+ * memory leaks if we error out during parsing.  Note this only works with
+ * bison >= 2.0.  However, in bison 1.875 the default is to use alloca()
+ * if possible, so there's not really much problem anyhow, at least if
+ * you're building with gcc.
+ */
+#define YYMALLOC palloc
+#define YYFREE   pfree
+
+
 static PLpgSQL_expr		*read_sql_construct(int until,
 											int until2,
 											int until3,