/*-------------------------------------------------------------------------
 *
 * test_explain_state.c
 *	  Crash reproducer for the sizeof bug in RegisterExtensionExplainOption.
 *
 *	  RegisterExtensionExplainOption allocates its ExplainExtensionOptionArray
 *	  using sizeof(char *) (8 bytes) instead of sizeof(ExplainExtensionOption)
 *	  (16 bytes).  The initial allocation is for 16 "slots" at 8 bytes each =
 *	  128 bytes, but each ExplainExtensionOption is 16 bytes, so only 8 entries
 *	  actually fit.  Registering a 9th option writes past the end of the
 *	  allocation, corrupting the heap.
 *
 *	  This module registers 10 options, which is enough to trigger the bug.
 */
#include "postgres.h"

#include "commands/defrem.h"
#include "commands/explain_state.h"
#include "fmgr.h"

PG_MODULE_MAGIC;

static const char *const option_names[] = {
	"test_explain_opt0",
	"test_explain_opt1",
	"test_explain_opt2",
	"test_explain_opt3",
	"test_explain_opt4",
	"test_explain_opt5",
	"test_explain_opt6",
	"test_explain_opt7",
	"test_explain_opt8",
	"test_explain_opt9",
};

#define NUM_OPTIONS lengthof(option_names)

static void test_explain_option_handler(ExplainState *es, DefElem *opt,
										ParseState *pstate);

void
_PG_init(void)
{
	for (int i = 0; i < NUM_OPTIONS; i++)
		RegisterExtensionExplainOption(option_names[i],
									   test_explain_option_handler);
}

static void
test_explain_option_handler(ExplainState *es, DefElem *opt,
							ParseState *pstate)
{
	ereport(NOTICE,
			(errmsg("test_explain_state: processed option \"%s\"",
					opt->defname)));
}