From f8d67ca8d4cbbbd6c6b3319d531089880d332534 Mon Sep 17 00:00:00 2001
From: Alvaro Herrera <alvherre@alvh.no-ip.org>
Date: Sun, 19 Jul 2015 12:26:14 +0200
Subject: [PATCH] Fix (some of) pltcl memory usage
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As reported by Bill Parker, PL/Tcl did not validate some malloc() calls
against NULL return. Fix by using palloc() in a new long-lived memory
context instead. This allows us to simplify error handling too, by
simply deleting the memory context instead of doing retail frees.
There's still a lot that could be done to improve PL/Tcl's memory
handling ...
This is pretty ancient, so backpatch all the way back.
Author: Michael Paquier and Ãlvaro Herrera
Discussion: https://www.postgresql.org/message-id/CAFrbyQwyLDYXfBOhPfoBGqnvuZO_Y90YgqFM11T2jvnxjLFmqw@mail.gmail.com
---
src/pl/tcl/pltcl.c | 27 ++++++++++++++++++---------
1 file changed, 18 insertions(+), 9 deletions(-)
diff --git a/src/pl/tcl/pltcl.c b/src/pl/tcl/pltcl.c
index d6b72f7d686..48a3206da1c 100644
--- a/src/pl/tcl/pltcl.c
+++ b/src/pl/tcl/pltcl.c
@@ -2104,6 +2104,7 @@ static int
pltcl_SPI_prepare(ClientData cdata, Tcl_Interp *interp,
int argc, CONST84 char *argv[])
{
+ volatile MemoryContext plan_cxt = NULL;
int nargs;
CONST84 char **args;
pltcl_query_desc *qdesc;
@@ -2132,13 +2133,24 @@ pltcl_SPI_prepare(ClientData cdata, Tcl_Interp *interp,
/************************************************************
* Allocate the new querydesc structure
+ *
+ * struct qdesc and subsidiary data all live in plan_cxt. Note that if the
+ * function is recompiled for whatever reason, permanent memory leaks
+ * occur. FIXME someday.
************************************************************/
- qdesc = (pltcl_query_desc *) malloc(sizeof(pltcl_query_desc));
+ plan_cxt = AllocSetContextCreate(TopMemoryContext,
+ "PL/TCL spi_prepare query",
+ ALLOCSET_SMALL_MINSIZE,
+ ALLOCSET_SMALL_INITSIZE,
+ ALLOCSET_SMALL_MAXSIZE);
+ MemoryContextSwitchTo(plan_cxt);
+ qdesc = (pltcl_query_desc *) palloc0(sizeof(pltcl_query_desc));
snprintf(qdesc->qname, sizeof(qdesc->qname), "%p", qdesc);
qdesc->nargs = nargs;
- qdesc->argtypes = (Oid *) malloc(nargs * sizeof(Oid));
- qdesc->arginfuncs = (FmgrInfo *) malloc(nargs * sizeof(FmgrInfo));
- qdesc->argtypioparams = (Oid *) malloc(nargs * sizeof(Oid));
+ qdesc->argtypes = (Oid *) palloc(nargs * sizeof(Oid));
+ qdesc->arginfuncs = (FmgrInfo *) palloc(nargs * sizeof(FmgrInfo));
+ qdesc->argtypioparams = (Oid *) palloc(nargs * sizeof(Oid));
+ MemoryContextSwitchTo(oldcontext);
/************************************************************
* Execute the prepare inside a sub-transaction, so we can cope with
@@ -2166,7 +2178,7 @@ pltcl_SPI_prepare(ClientData cdata, Tcl_Interp *interp,
getTypeInputInfo(typId, &typInput, &typIOParam);
qdesc->argtypes[i] = typId;
- perm_fmgr_info(typInput, &(qdesc->arginfuncs[i]));
+ fmgr_info_cxt(typInput, &(qdesc->arginfuncs[i]), plan_cxt);
qdesc->argtypioparams[i] = typIOParam;
}
@@ -2193,10 +2205,7 @@ pltcl_SPI_prepare(ClientData cdata, Tcl_Interp *interp,
{
pltcl_subtrans_abort(interp, oldcontext, oldowner);
- free(qdesc->argtypes);
- free(qdesc->arginfuncs);
- free(qdesc->argtypioparams);
- free(qdesc);
+ MemoryContextDelete(plan_cxt);
ckfree((char *) args);
return TCL_ERROR;
--
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