Use portal pinning in PL/Perl and PL/Python

petere · petere · commit 70d6226e4fba · 2018-01-10T17:10:32.000-05:00
PL/pgSQL "pins" internally generated portals so that user code cannot
close them by guessing their names.  Add this functionality to PL/Perl
and PL/Python as well, preventing users from manually closing cursors
created by spi_query and plpy.cursor, respectively.  (PL/Tcl does not
currently offer any cursor functionality.)
diff --git a/src/pl/plperl/plperl.c b/src/pl/plperl/plperl.c
@@ -3406,6 +3406,8 @@ plperl_spi_query(char *query)
 				 SPI_result_code_string(SPI_result));
 		cursor = cstr2sv(portal->name);
 
+		PinPortal(portal);
+
 		/* Commit the inner transaction, return to outer xact context */
 		ReleaseCurrentSubTransaction();
 		MemoryContextSwitchTo(oldcontext);
@@ -3469,6 +3471,7 @@ plperl_spi_fetchrow(char *cursor)
 			SPI_cursor_fetch(p, true, 1);
 			if (SPI_processed == 0)
 			{
+				UnpinPortal(p);
 				SPI_cursor_close(p);
 				row = &PL_sv_undef;
 			}
@@ -3520,7 +3523,10 @@ plperl_spi_cursor_close(char *cursor)
 	p = SPI_cursor_find(cursor);
 
 	if (p)
+	{
+		UnpinPortal(p);
 		SPI_cursor_close(p);
+	}
 }
 
 SV *
@@ -3884,6 +3890,8 @@ plperl_spi_query_prepared(char *query, int argc, SV **argv)
 
 		cursor = cstr2sv(portal->name);
 
+		PinPortal(portal);
+
 		/* Commit the inner transaction, return to outer xact context */
 		ReleaseCurrentSubTransaction();
 		MemoryContextSwitchTo(oldcontext);
diff --git a/src/pl/plpython/plpy_cursorobject.c b/src/pl/plpython/plpy_cursorobject.c
@@ -151,6 +151,8 @@ PLy_cursor_query(const char *query)
 
 		cursor->portalname = MemoryContextStrdup(cursor->mcxt, portal->name);
 
+		PinPortal(portal);
+
 		PLy_spi_subtransaction_commit(oldcontext, oldowner);
 	}
 	PG_CATCH();
@@ -266,6 +268,8 @@ PLy_cursor_plan(PyObject *ob, PyObject *args)
 
 		cursor->portalname = MemoryContextStrdup(cursor->mcxt, portal->name);
 
+		PinPortal(portal);
+
 		PLy_spi_subtransaction_commit(oldcontext, oldowner);
 	}
 	PG_CATCH();
@@ -317,7 +321,10 @@ PLy_cursor_dealloc(PyObject *arg)
 		portal = GetPortalByName(cursor->portalname);
 
 		if (PortalIsValid(portal))
+		{
+			UnpinPortal(portal);
 			SPI_cursor_close(portal);
+		}
 		cursor->closed = true;
 	}
 	if (cursor->mcxt)
@@ -508,6 +515,7 @@ PLy_cursor_close(PyObject *self, PyObject *unused)
 			return NULL;
 		}
 
+		UnpinPortal(portal);
 		SPI_cursor_close(portal);
 		cursor->closed = true;
 	}

Original file line number	Diff line number	Diff line change
`@@ -151,6 +151,8 @@ PLy_cursor_query(const char *query)`
`151`	`151`
`152`	`152`	`cursor->portalname = MemoryContextStrdup(cursor->mcxt, portal->name);`
`153`	`153`
	`154`	`+ PinPortal(portal);`
	`155`	`+`
`154`	`156`	`PLy_spi_subtransaction_commit(oldcontext, oldowner);`
`155`	`157`	`}`
`156`	`158`	`PG_CATCH();`
`@@ -266,6 +268,8 @@ PLy_cursor_plan(PyObject ob, PyObject args)`
`266`	`268`
`267`	`269`	`cursor->portalname = MemoryContextStrdup(cursor->mcxt, portal->name);`
`268`	`270`
	`271`	`+ PinPortal(portal);`
	`272`	`+`
`269`	`273`	`PLy_spi_subtransaction_commit(oldcontext, oldowner);`
`270`	`274`	`}`
`271`	`275`	`PG_CATCH();`
`@@ -317,7 +321,10 @@ PLy_cursor_dealloc(PyObject *arg)`
`317`	`321`	`portal = GetPortalByName(cursor->portalname);`
`318`	`322`
`319`	`323`	`if (PortalIsValid(portal))`
	`324`	`+ {`
	`325`	`+ UnpinPortal(portal);`
`320`	`326`	`SPI_cursor_close(portal);`
	`327`	`+ }`
`321`	`328`	`cursor->closed = true;`
`322`	`329`	`}`
`323`	`330`	`if (cursor->mcxt)`
`@@ -508,6 +515,7 @@ PLy_cursor_close(PyObject self, PyObject unused)`
`508`	`515`	`return NULL;`
`509`	`516`	`}`
`510`	`517`
	`518`	`+ UnpinPortal(portal);`
`511`	`519`	`SPI_cursor_close(portal);`
`512`	`520`	`cursor->closed = true;`
`513`	`521`	`}`