pg_dump memory leak of 400 bytes

[Oleg Tselebrovskiy]

Greetings, everyone!

When I was looking through static analyzer output I've found a memory 
leak in pg_dump

In function dumpFunc, when dumping a function with TRANSFORMs, we 
allocate
memory for typeids array that contains OIDs of types that need to be 
transformed.
The memory is allocated with palloc and is never freed.

Valgrind also confirms this:

1) Create TRANSFORM and FUNCTION using it:
CREATE TRANSFORM FOR int LANGUAGE SQL (FROM SQL WITH FUNCTION 
prsd_lextype(internal),
                                                                                
 TO SQL WITH FUNCTION int4recv(internal));
CREATE FUNCTION add(int, int) RETURNS int
    AS 'select $1 + $2;'
    LANGUAGE SQL TRANSFORM FOR TYPE int;

2) Use valgrind to observe the memory leak:
valgrind --leak-check=yes --time-stamp=yes 
--error-markers=VALGRINDERROR-BEGIN,VALGRINDERROR-END ./pg_dump -f 
somedump.sql
...
==00:00:00:00.764 50282== VALGRINDERROR-BEGIN
==00:00:00:00.764 50282== 400 bytes in 1 blocks are definitely lost in 
loss record 92 of 134
==00:00:00:00.764 50282==    at 0x4848899: malloc (in 
/usr/libexec/valgrind/vgpreload_memcheck-amd64-linux.so)
==00:00:00:00.764 50282==    by 0x14B758: palloc (fe_memutils.c:107)
==00:00:00:00.764 50282==    by 0x120D99: dumpFunc (pg_dump.c:12534)
==00:00:00:00.764 50282==    by 0x10F764: main (pg_dump.c:1085)
==00:00:00:00.764 50282==
==00:00:00:00.764 50282== VALGRINDERROR-END
{
   <insert_a_suppression_name_here>
   Memcheck:Leak
   match-leak-kinds: definite
   fun:malloc
   fun:palloc
   fun:dumpFunc
   fun:main
}
...

Also, we always allocate the same ammount of memory (FUNC_MAX_ARGS * 
sizeof(Oid))

I propose two solutions for this problem:
1) Just free the memory in the end of this code block
2) Use static allocation since it is always the same amount

Patches for both variants are attached. I also propose changing palloc 
to pg_malloc
since it is the only place in pg_dump where palloc is used instead of 
pg_malloc

Oleg Tselebrovskiy, Postgres Prodiff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index ec0cdf4ed74..9a24ebfca24 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -12531,7 +12531,7 @@ dumpFunc(Archive *fout, const FuncInfo *finfo)
 
 	if (*protrftypes)
 	{
-		Oid		   *typeids = palloc(FUNC_MAX_ARGS * sizeof(Oid));
+		Oid		   *typeids = pg_malloc(FUNC_MAX_ARGS * sizeof(Oid));
 		int			i;
 
 		appendPQExpBufferStr(q, " TRANSFORM ");
@@ -12543,6 +12543,7 @@ dumpFunc(Archive *fout, const FuncInfo *finfo)
 			appendPQExpBuffer(q, "FOR TYPE %s",
 							  getFormattedTypeName(fout, typeids[i], zeroAsNone));
 		}
+		free(typeids);
 	}
 
 	if (prokind[0] == PROKIND_WINDOW)
diff --git a/src/bin/pg_dump/pg_dump.c b/src/bin/pg_dump/pg_dump.c
index ec0cdf4ed74..c63b76aa382 100644
--- a/src/bin/pg_dump/pg_dump.c
+++ b/src/bin/pg_dump/pg_dump.c
@@ -12531,7 +12531,7 @@ dumpFunc(Archive *fout, const FuncInfo *finfo)
 
 	if (*protrftypes)
 	{
-		Oid		   *typeids = palloc(FUNC_MAX_ARGS * sizeof(Oid));
+		Oid		    typeids[FUNC_MAX_ARGS];
 		int			i;
 
 		appendPQExpBufferStr(q, " TRANSFORM ");