public inbox for [email protected]  
help / color / mirror / Atom feed
[PATCH 1/5] bootstrap: convert Typ to a List*
7+ messages / 5 participants
[nested] [flat]

* [PATCH 1/5] bootstrap: convert Typ to a List*
@ 2020-11-20 02:48  Justin Pryzby <[email protected]>
  0 siblings, 0 replies; 7+ messages in thread

From: Justin Pryzby @ 2020-11-20 02:48 UTC (permalink / raw)

---
 src/backend/bootstrap/bootstrap.c | 69 ++++++++++++++-----------------
 1 file changed, 31 insertions(+), 38 deletions(-)

diff --git a/src/backend/bootstrap/bootstrap.c b/src/backend/bootstrap/bootstrap.c
index 6f615e6622..18eb62ca47 100644
--- a/src/backend/bootstrap/bootstrap.c
+++ b/src/backend/bootstrap/bootstrap.c
@@ -159,7 +159,7 @@ struct typmap
 	FormData_pg_type am_typ;
 };
 
-static struct typmap **Typ = NULL;
+static List *Typ = NIL; /* List of struct typmap* */
 static struct typmap *Ap = NULL;
 
 static Datum values[MAXATTR];	/* current row's attribute values */
@@ -597,7 +597,7 @@ boot_openrel(char *relname)
 	 * pg_type must be filled before any OPEN command is executed, hence we
 	 * can now populate the Typ array if we haven't yet.
 	 */
-	if (Typ == NULL)
+	if (Typ == NIL)
 		populate_typ_array();
 
 	if (boot_reldesc != NULL)
@@ -688,7 +688,7 @@ DefineAttr(char *name, char *type, int attnum, int nullness)
 
 	typeoid = gettype(type);
 
-	if (Typ != NULL)
+	if (Typ != NIL)
 	{
 		attrtypes[attnum]->atttypid = Ap->am_oid;
 		attrtypes[attnum]->attlen = Ap->am_typ.typlen;
@@ -877,36 +877,25 @@ populate_typ_array(void)
 	Relation	rel;
 	TableScanDesc scan;
 	HeapTuple	tup;
-	int			nalloc;
-	int			i;
-
-	Assert(Typ == NULL);
 
-	nalloc = 512;
-	Typ = (struct typmap **)
-		MemoryContextAlloc(TopMemoryContext, nalloc * sizeof(struct typmap *));
+	Assert(Typ == NIL);
 
 	rel = table_open(TypeRelationId, NoLock);
 	scan = table_beginscan_catalog(rel, 0, NULL);
-	i = 0;
 	while ((tup = heap_getnext(scan, ForwardScanDirection)) != NULL)
 	{
 		Form_pg_type typForm = (Form_pg_type) GETSTRUCT(tup);
+		struct typmap *newtyp;
+		MemoryContext old;
 
-		/* make sure there will be room for a trailing NULL pointer */
-		if (i >= nalloc - 1)
-		{
-			nalloc *= 2;
-			Typ = (struct typmap **)
-				repalloc(Typ, nalloc * sizeof(struct typmap *));
-		}
-		Typ[i] = (struct typmap *)
-			MemoryContextAlloc(TopMemoryContext, sizeof(struct typmap));
-		Typ[i]->am_oid = typForm->oid;
-		memcpy(&(Typ[i]->am_typ), typForm, sizeof(Typ[i]->am_typ));
-		i++;
+		old = MemoryContextSwitchTo(TopMemoryContext);
+		newtyp = (struct typmap *) palloc(sizeof(struct typmap));
+		Typ = lappend(Typ, newtyp);
+		MemoryContextSwitchTo(old);
+
+		newtyp->am_oid = typForm->oid;
+		memcpy(&newtyp->am_typ, typForm, sizeof(newtyp->am_typ));
 	}
-	Typ[i] = NULL;				/* Fill trailing NULL pointer */
 	table_endscan(scan);
 	table_close(rel, NoLock);
 }
@@ -925,16 +914,17 @@ populate_typ_array(void)
 static Oid
 gettype(char *type)
 {
-	if (Typ != NULL)
+	if (Typ != NIL)
 	{
-		struct typmap **app;
+		ListCell *lc;
 
-		for (app = Typ; *app != NULL; app++)
+		foreach (lc, Typ)
 		{
-			if (strncmp(NameStr((*app)->am_typ.typname), type, NAMEDATALEN) == 0)
+			struct typmap *app = lfirst(lc);
+			if (strncmp(NameStr(app->am_typ.typname), type, NAMEDATALEN) == 0)
 			{
-				Ap = *app;
-				return (*app)->am_oid;
+				Ap = app;
+				return app->am_oid;
 			}
 		}
 	}
@@ -980,14 +970,17 @@ boot_get_type_io_data(Oid typid,
 	if (Typ != NULL)
 	{
 		/* We have the boot-time contents of pg_type, so use it */
-		struct typmap **app;
-		struct typmap *ap;
-
-		app = Typ;
-		while (*app && (*app)->am_oid != typid)
-			++app;
-		ap = *app;
-		if (ap == NULL)
+		struct typmap *ap = NULL;
+		ListCell *lc;
+
+		foreach (lc, Typ)
+		{
+			ap = lfirst(lc);
+			if (ap->am_oid == typid)
+				break;
+		}
+
+		if (!ap || ap->am_oid != typid)
 			elog(ERROR, "type OID %u not found in Typ list", typid);
 
 		*typlen = ap->am_typ.typlen;
-- 
2.26.2


--------------614DDB87AFFED893713AC0E9
Content-Type: text/x-patch; charset=UTF-8;
 name="0002-Allow-composite-types-in-bootstrap-20210304.patch"
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment;
 filename="0002-Allow-composite-types-in-bootstrap-20210304.patch"



^ permalink  raw  reply  [nested|flat] 7+ messages in thread

* Re: Fix use of possible uninitialized variable retval (src/pl/plpgsql/src/pl_handler.c)
@ 2024-06-05 04:12  Kyotaro Horiguchi <[email protected]>
  0 siblings, 2 replies; 7+ messages in thread

From: Kyotaro Horiguchi @ 2024-06-05 04:12 UTC (permalink / raw)
  To: [email protected]; +Cc: pgsql-hackers

At Mon, 27 May 2024 11:31:24 -0300, Ranier Vilela <[email protected]> wrote in 
> Hi.
> 
> The function *plpgsql_inline_handler* can use uninitialized
> variable retval, if PG_TRY fails.
> Fix like function*plpgsql_call_handler* wich declare retval as
> volatile and initialize to (Datum 0).

If PG_TRY fails, retval is not actually accessed, so no real issue
exists. Commit 7292fd8f1c changed plpgsql_call_handler() to the
current form, but as stated in its commit message, it did not fix a
real issue and was solely to silence compiler.

I believe we do not need to modify plpgsql_inline_handler() unless
compiler actually issues a false warning for it.

regards.

-- 
Kyotaro Horiguchi
NTT Open Source Software Center






^ permalink  raw  reply  [nested|flat] 7+ messages in thread

* Re: Fix use of possible uninitialized variable retval (src/pl/plpgsql/src/pl_handler.c)
@ 2024-06-05 05:04  Michael Paquier <[email protected]>
  parent: Kyotaro Horiguchi <[email protected]>
  1 sibling, 2 replies; 7+ messages in thread

From: Michael Paquier @ 2024-06-05 05:04 UTC (permalink / raw)
  To: Kyotaro Horiguchi <[email protected]>; +Cc: [email protected]; pgsql-hackers

On Wed, Jun 05, 2024 at 01:12:41PM +0900, Kyotaro Horiguchi wrote:
> At Mon, 27 May 2024 11:31:24 -0300, Ranier Vilela <[email protected]> wrote in 
>> The function *plpgsql_inline_handler* can use uninitialized
>> variable retval, if PG_TRY fails.
>> Fix like function*plpgsql_call_handler* wich declare retval as
>> volatile and initialize to (Datum 0).

You forgot to read elog.h, explaining under which circumstances
variables related to TRY/CATCH block should be marked as volatile.
There is a big "Note:" paragraph.

It is not the first time that this is mentioned on this list: but
sending a report without looking at the reason why a change is
justified makes everybody waste time.  That's not productive.

> If PG_TRY fails, retval is not actually accessed, so no real issue
> exists. Commit 7292fd8f1c changed plpgsql_call_handler() to the
> current form, but as stated in its commit message, it did not fix a
> real issue and was solely to silence compiler.

This complain was from lapwing, that uses a version of gcc which
produces a lot of noise with incorrect issues.  It is one of the only
32b buildfarm members, so it still has a lot of value.

> I believe we do not need to modify plpgsql_inline_handler() unless
> compiler actually issues a false warning for it.

If we were to do something, that would be to remove the volatile from
plpgsql_call_handler() at the end once we don't have in the buildfarm
compilers that complain about it, because there is no reason to use a
volatile in this case.  :)
--
Michael


Attachments:

  [application/pgp-signature] signature.asc (833B, ../../[email protected]/2-signature.asc)
  download

^ permalink  raw  reply  [nested|flat] 7+ messages in thread

* Re: Fix use of possible uninitialized variable retval (src/pl/plpgsql/src/pl_handler.c)
@ 2024-06-05 12:28  Ranier Vilela <[email protected]>
  parent: Kyotaro Horiguchi <[email protected]>
  1 sibling, 0 replies; 7+ messages in thread

From: Ranier Vilela @ 2024-06-05 12:28 UTC (permalink / raw)
  To: Kyotaro Horiguchi <[email protected]>; +Cc: pgsql-hackers

Em qua., 5 de jun. de 2024 às 01:12, Kyotaro Horiguchi <
[email protected]> escreveu:

> At Mon, 27 May 2024 11:31:24 -0300, Ranier Vilela <[email protected]>
> wrote in
> > Hi.
> >
> > The function *plpgsql_inline_handler* can use uninitialized
> > variable retval, if PG_TRY fails.
> > Fix like function*plpgsql_call_handler* wich declare retval as
> > volatile and initialize to (Datum 0).
>
> If PG_TRY fails, retval is not actually accessed, so no real issue
> exists.

You say it for this call
PG_RE_THROW();


> Commit 7292fd8f1c changed plpgsql_call_handler() to the
> current form, but as stated in its commit message, it did not fix a
> real issue and was solely to silence compiler.
>

> I believe we do not need to modify plpgsql_inline_handler() unless
> compiler actually issues a false warning for it.
>
Yeah, there is a warning, but not from the compiler.

best regards,
Ranier Vilela


^ permalink  raw  reply  [nested|flat] 7+ messages in thread

* Re: Fix use of possible uninitialized variable retval (src/pl/plpgsql/src/pl_handler.c)
@ 2024-06-05 12:34  Ranier Vilela <[email protected]>
  parent: Michael Paquier <[email protected]>
  1 sibling, 0 replies; 7+ messages in thread

From: Ranier Vilela @ 2024-06-05 12:34 UTC (permalink / raw)
  To: Michael Paquier <[email protected]>; +Cc: Kyotaro Horiguchi <[email protected]>; pgsql-hackers

Em qua., 5 de jun. de 2024 às 02:04, Michael Paquier <[email protected]>
escreveu:

> On Wed, Jun 05, 2024 at 01:12:41PM +0900, Kyotaro Horiguchi wrote:
> > At Mon, 27 May 2024 11:31:24 -0300, Ranier Vilela <[email protected]>
> wrote in
> >> The function *plpgsql_inline_handler* can use uninitialized
> >> variable retval, if PG_TRY fails.
> >> Fix like function*plpgsql_call_handler* wich declare retval as
> >> volatile and initialize to (Datum 0).
>
> You forgot to read elog.h, explaining under which circumstances
> variables related to TRY/CATCH block should be marked as volatile.
> There is a big "Note:" paragraph.
>
> It is not the first time that this is mentioned on this list: but
> sending a report without looking at the reason why a change is
> justified makes everybody waste time.  That's not productive.
>
Of course, this is very bad when it happens.


>
> > If PG_TRY fails, retval is not actually accessed, so no real issue
> > exists. Commit 7292fd8f1c changed plpgsql_call_handler() to the
> > current form, but as stated in its commit message, it did not fix a
> > real issue and was solely to silence compiler.
>
> This complain was from lapwing, that uses a version of gcc which
> produces a lot of noise with incorrect issues.  It is one of the only
> 32b buildfarm members, so it still has a lot of value.
>
I posted the report, because of an uninitialized variable warning.
Which is one of the most problematic situations, when it *actually exists*.


> > I believe we do not need to modify plpgsql_inline_handler() unless
> > compiler actually issues a false warning for it.
>
> If we were to do something, that would be to remove the volatile from
> plpgsql_call_handler() at the end once we don't have in the buildfarm
> compilers that complain about it, because there is no reason to use a
> volatile in this case.  :)
>
I don't see any motivation, since there are no reports.

best regards,
Ranier Vilela


^ permalink  raw  reply  [nested|flat] 7+ messages in thread

* Re: Fix use of possible uninitialized variable retval (src/pl/plpgsql/src/pl_handler.c)
@ 2024-06-05 14:27  Julien Rouhaud <[email protected]>
  parent: Michael Paquier <[email protected]>
  1 sibling, 1 reply; 7+ messages in thread

From: Julien Rouhaud @ 2024-06-05 14:27 UTC (permalink / raw)
  To: Michael Paquier <[email protected]>; +Cc: Kyotaro Horiguchi <[email protected]>; [email protected]; pgsql-hackers

On Wed, Jun 5, 2024 at 1:05 PM Michael Paquier <[email protected]> wrote:
>
> This complain was from lapwing, that uses a version of gcc which
> produces a lot of noise with incorrect issues.  It is one of the only
> 32b buildfarm members, so it still has a lot of value.

Note that I removed the -Werror from lapwing a long time ago, so at
least this animal shouldn't lead to hackish fixes for false positive
anymore.






^ permalink  raw  reply  [nested|flat] 7+ messages in thread

* Re: Fix use of possible uninitialized variable retval (src/pl/plpgsql/src/pl_handler.c)
@ 2024-06-06 04:29  Michael Paquier <[email protected]>
  parent: Julien Rouhaud <[email protected]>
  0 siblings, 0 replies; 7+ messages in thread

From: Michael Paquier @ 2024-06-06 04:29 UTC (permalink / raw)
  To: Julien Rouhaud <[email protected]>; +Cc: Kyotaro Horiguchi <[email protected]>; [email protected]; pgsql-hackers

On Wed, Jun 05, 2024 at 10:27:51PM +0800, Julien Rouhaud wrote:
> Note that I removed the -Werror from lapwing a long time ago, so at
> least this animal shouldn't lead to hackish fixes for false positive
> anymore.

That's good to know.  Thanks for the update.
--
Michael


Attachments:

  [application/pgp-signature] signature.asc (833B, ../../[email protected]/2-signature.asc)
  download

^ permalink  raw  reply  [nested|flat] 7+ messages in thread


end of thread, other threads:[~2024-06-06 04:29 UTC | newest]

Thread overview: 7+ messages (download: mbox mbox.gz follow: Atom feed)
-- links below jump to the message on this page --
2020-11-20 02:48 [PATCH 1/5] bootstrap: convert Typ to a List* Justin Pryzby <[email protected]>
2024-06-05 04:12 Re: Fix use of possible uninitialized variable retval (src/pl/plpgsql/src/pl_handler.c) Kyotaro Horiguchi <[email protected]>
2024-06-05 05:04 ` Re: Fix use of possible uninitialized variable retval (src/pl/plpgsql/src/pl_handler.c) Michael Paquier <[email protected]>
2024-06-05 12:34   ` Re: Fix use of possible uninitialized variable retval (src/pl/plpgsql/src/pl_handler.c) Ranier Vilela <[email protected]>
2024-06-05 14:27   ` Re: Fix use of possible uninitialized variable retval (src/pl/plpgsql/src/pl_handler.c) Julien Rouhaud <[email protected]>
2024-06-06 04:29     ` Re: Fix use of possible uninitialized variable retval (src/pl/plpgsql/src/pl_handler.c) Michael Paquier <[email protected]>
2024-06-05 12:28 ` Re: Fix use of possible uninitialized variable retval (src/pl/plpgsql/src/pl_handler.c) Ranier Vilela <[email protected]>

This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox