Add plperl.on_perl_init setting to provide for initializing the perl library on load. Also, handle END blocks in plperl.

Database access is disallowed during both these operations, although it might be allowed in END blocks in future.

Patch from Tim Bunce.

4 files changed, 193 insertions, 19 deletions

diff --git a/src/pl/plperl/plc_perlboot.pl b/src/pl/plperl/plc_perlboot.pl
index f0210e54f90..9364a30ece3 100644
--- a/src/pl/plperl/plc_perlboot.pl
+++ b/src/pl/plperl/plc_perlboot.pl
@@ -1,8 +1,7 @@
 
-#  $PostgreSQL: pgsql/src/pl/plperl/plc_perlboot.pl,v 1.3 2010/01/26 23:11:56 adunstan Exp $
+#  $PostgreSQL: pgsql/src/pl/plperl/plc_perlboot.pl,v 1.4 2010/01/30 01:46:57 adunstan Exp $
 
 PostgreSQL::InServer::Util::bootstrap();
-PostgreSQL::InServer::SPI::bootstrap();
 
 use strict;
 use warnings;
diff --git a/src/pl/plperl/plperl.c b/src/pl/plperl/plperl.c
index 1a1e264e9d4..97471edc9ba 100644
--- a/src/pl/plperl/plperl.c
+++ b/src/pl/plperl/plperl.c
@@ -1,7 +1,7 @@
 /**********************************************************************
  * plperl.c - perl as a procedural language for PostgreSQL
  *
- *	  $PostgreSQL: pgsql/src/pl/plperl/plperl.c,v 1.162 2010/01/28 23:06:09 adunstan Exp $
+ *	  $PostgreSQL: pgsql/src/pl/plperl/plperl.c,v 1.163 2010/01/30 01:46:57 adunstan Exp $
  *
  **********************************************************************/
 
@@ -27,6 +27,7 @@
 #include "miscadmin.h"
 #include "nodes/makefuncs.h"
 #include "parser/parse_type.h"
+#include "storage/ipc.h"
 #include "utils/builtins.h"
 #include "utils/fmgroids.h"
 #include "utils/guc.h"
@@ -138,6 +139,8 @@ static HTAB *plperl_proc_hash = NULL;
 static HTAB *plperl_query_hash = NULL;
 
 static bool plperl_use_strict = false;
+static char *plperl_on_perl_init = NULL;
+static bool plperl_ending = false;
 
 /* this is saved and restored by plperl_call_handler */
 static plperl_call_data *current_call_data = NULL;
@@ -151,6 +154,8 @@ Datum		plperl_validator(PG_FUNCTION_ARGS);
 void		_PG_init(void);
 
 static PerlInterpreter *plperl_init_interp(void);
+static void plperl_destroy_interp(PerlInterpreter **);
+static void plperl_fini(int code, Datum arg);
 
 static Datum plperl_func_handler(PG_FUNCTION_ARGS);
 static Datum plperl_trigger_handler(PG_FUNCTION_ARGS);
@@ -237,6 +242,14 @@ _PG_init(void)
 							 PGC_USERSET, 0,
 							 NULL, NULL);
 
+	DefineCustomStringVariable("plperl.on_perl_init",
+							gettext_noop("Perl code to execute when the perl interpreter is initialized."),
+							NULL,
+							&plperl_on_perl_init,
+							NULL,
+							PGC_SIGHUP, 0,
+							NULL, NULL);
+
 	EmitWarningsOnPlaceholders("plperl");
 
 	MemSet(&hash_ctl, 0, sizeof(hash_ctl));
@@ -261,6 +274,37 @@ _PG_init(void)
 	inited = true;
 }
 
+
+/*
+ * Cleanup perl interpreters, including running END blocks.
+ * Does not fully undo the actions of _PG_init() nor make it callable again.
+ */
+static void
+plperl_fini(int code, Datum arg)
+{
+	elog(DEBUG3, "plperl_fini");
+
+	/*
+	 * Disable use of spi_* functions when running END/DESTROY code.
+	 * Could be enabled in future, with care, using a transaction
+	 * http://archives.postgresql.org/pgsql-hackers/2010-01/msg02743.php
+	 */
+	plperl_ending = true;
+
+	/* Only perform perl cleanup if we're exiting cleanly */
+	if (code) {
+		elog(DEBUG3, "plperl_fini: skipped");
+		return;
+	}
+
+	plperl_destroy_interp(&plperl_trusted_interp);
+	plperl_destroy_interp(&plperl_untrusted_interp);
+	plperl_destroy_interp(&plperl_held_interp);
+
+	elog(DEBUG3, "plperl_fini: done");
+}
+
+
 #define SAFE_MODULE \
 	"require Safe; $Safe::VERSION"
 
@@ -277,6 +321,8 @@ _PG_init(void)
 static void
 select_perl_context(bool trusted)
 {
+	EXTERN_C void boot_PostgreSQL__InServer__SPI(pTHX_ CV *cv);
+
 	/*
 	 * handle simple cases
 	 */
@@ -288,6 +334,10 @@ select_perl_context(bool trusted)
 	 */
 	if (interp_state == INTERP_HELD)
 	{
+		/* first actual use of a perl interpreter */
+
+		on_proc_exit(plperl_fini, 0);
+
 		if (trusted)
 		{
 			plperl_trusted_interp = plperl_held_interp;
@@ -325,6 +375,22 @@ select_perl_context(bool trusted)
 		plperl_safe_init();
 		PL_ppaddr[OP_REQUIRE] = pp_require_safe;
 	}
+
+	/*
+	 * enable access to the database
+	 */
+	newXS("PostgreSQL::InServer::SPI::bootstrap",
+		boot_PostgreSQL__InServer__SPI, __FILE__);
+
+	eval_pv("PostgreSQL::InServer::SPI::bootstrap()", FALSE);
+	if (SvTRUE(ERRSV))
+	{
+		ereport(ERROR,
+			(errcode(ERRCODE_INTERNAL_ERROR),
+			errmsg("%s", strip_trailing_ws(SvPV_nolen(ERRSV))),
+			errdetail("While executing PostgreSQL::InServer::SPI::bootstrap")));
+	}
+
 }
 
 /*
@@ -361,7 +427,7 @@ plperl_init_interp(void)
 	PerlInterpreter *plperl;
 	static int perl_sys_init_done;
 
-	static char *embedding[3] = {
+	static char *embedding[3+2] = {
 		"", "-e", PLC_PERLBOOT
 	};
 	int			nargs = 3;
@@ -408,6 +474,12 @@ plperl_init_interp(void)
 	save_time = loc ? pstrdup(loc) : NULL;
 #endif
 
+	if (plperl_on_perl_init)
+	{
+		embedding[nargs++] = "-e";
+		embedding[nargs++] = plperl_on_perl_init;
+	}
+
 	/****
 	 * The perl API docs state that PERL_SYS_INIT3 should be called before
 	 * allocating interprters. Unfortunately, on some platforms this fails
@@ -437,6 +509,9 @@ plperl_init_interp(void)
 	PERL_SET_CONTEXT(plperl);
 	perl_construct(plperl);
 
+	/* run END blocks in perl_destruct instead of perl_run */
+	PL_exit_flags |= PERL_EXIT_DESTRUCT_END;
+
 	/*
 	 * Record the original function for the 'require' opcode.
 	 * Ensure it's used for new interpreters.
@@ -446,9 +521,18 @@ plperl_init_interp(void)
 	else
 		PL_ppaddr[OP_REQUIRE] = pp_require_orig;
 
-	perl_parse(plperl, plperl_init_shared_libs,
-			   nargs, embedding, NULL);
-	perl_run(plperl);
+	if (perl_parse(plperl, plperl_init_shared_libs,
+			   nargs, embedding, NULL) != 0)
+		ereport(ERROR,
+			(errcode(ERRCODE_INTERNAL_ERROR),
+				errmsg("while parsing perl initialization"),
+				errdetail("%s", strip_trailing_ws(SvPV_nolen(ERRSV))) ));
+
+	if (perl_run(plperl) != 0)
+		ereport(ERROR,
+			(errcode(ERRCODE_INTERNAL_ERROR),
+				errmsg("while running perl initialization"),
+				errdetail("%s", strip_trailing_ws(SvPV_nolen(ERRSV))) ));
 
 #ifdef WIN32
 
@@ -524,6 +608,43 @@ pp_require_safe(pTHX)
 
 
 static void
+plperl_destroy_interp(PerlInterpreter **interp)
+{
+	if (interp && *interp)
+	{
+		/*
+		 * Only a very minimal destruction is performed:
+		 * - just call END blocks.
+		 *
+		 * We could call perl_destruct() but we'd need to audit its
+		 * actions very carefully and work-around any that impact us.
+		 * (Calling sv_clean_objs() isn't an option because it's not
+		 * part of perl's public API so isn't portably available.)
+		 * Meanwhile END blocks can be used to perform manual cleanup.
+		 */
+
+		PERL_SET_CONTEXT(*interp);
+
+		/* Run END blocks - based on perl's perl_destruct() */
+		if (PL_exit_flags & PERL_EXIT_DESTRUCT_END) {
+			dJMPENV;
+			int x = 0;
+
+			JMPENV_PUSH(x);
+			PERL_UNUSED_VAR(x);
+			if (PL_endav && !PL_minus_c)
+				call_list(PL_scopestack_ix, PL_endav);
+			JMPENV_POP;
+		}
+		LEAVE;
+		FREETMPS;
+
+		*interp = NULL;
+	}
+}
+
+
+static void
 plperl_safe_init(void)
 {
 	SV		   *safe_version_sv;
@@ -544,8 +665,8 @@ plperl_safe_init(void)
 		{
 			ereport(ERROR,
 				(errcode(ERRCODE_INTERNAL_ERROR),
-				 errmsg("%s", strip_trailing_ws(SvPV_nolen(ERRSV))),
-				 errdetail("While executing PLC_SAFE_BAD")));
+				 errmsg("while executing PLC_SAFE_BAD"),
+				 errdetail("%s", strip_trailing_ws(SvPV_nolen(ERRSV))) ));
 		}
 
 	}
@@ -556,8 +677,8 @@ plperl_safe_init(void)
 		{
 			ereport(ERROR,
 				(errcode(ERRCODE_INTERNAL_ERROR),
-				 errmsg("%s", strip_trailing_ws(SvPV_nolen(ERRSV))),
-				 errdetail("While executing PLC_SAFE_OK")));
+				 errmsg("while executing PLC_SAFE_OK"),
+				 errdetail("%s", strip_trailing_ws(SvPV_nolen(ERRSV))) ));
 		}
 
 		if (GetDatabaseEncoding() == PG_UTF8)
@@ -1153,18 +1274,14 @@ plperl_create_sub(plperl_proc_desc *prodesc, char *s, Oid fn_oid)
  *
  **********************************************************************/
 
-EXTERN_C void boot_DynaLoader(pTHX_ CV *cv);
-EXTERN_C void boot_PostgreSQL__InServer__SPI(pTHX_ CV *cv);
-EXTERN_C void boot_PostgreSQL__InServer__Util(pTHX_ CV *cv);
-
 static void
 plperl_init_shared_libs(pTHX)
 {
 	char	   *file = __FILE__;
+	EXTERN_C void boot_DynaLoader(pTHX_ CV *cv);
+	EXTERN_C void boot_PostgreSQL__InServer__Util(pTHX_ CV *cv);
 
 	newXS("DynaLoader::boot_DynaLoader", boot_DynaLoader, file);
-	newXS("PostgreSQL::InServer::SPI::bootstrap",
-		  boot_PostgreSQL__InServer__SPI, file);
 	newXS("PostgreSQL::InServer::Util::bootstrap",
 		boot_PostgreSQL__InServer__Util, file);
 }
@@ -1900,6 +2017,16 @@ plperl_hash_from_tuple(HeapTuple tuple, TupleDesc tupdesc)
 }
 
 
+static void
+check_spi_usage_allowed()
+{
+	if (plperl_ending) {
+		/* simple croak as we don't want to involve PostgreSQL code */
+		croak("SPI functions can not be used in END blocks");
+	}
+}
+
+
 HV *
 plperl_spi_exec(char *query, int limit)
 {
@@ -1912,6 +2039,8 @@ plperl_spi_exec(char *query, int limit)
 	MemoryContext oldcontext = CurrentMemoryContext;
 	ResourceOwner oldowner = CurrentResourceOwner;
 
+	check_spi_usage_allowed();
+
 	BeginInternalSubTransaction(NULL);
 	/* Want to run inside function's memory context */
 	MemoryContextSwitchTo(oldcontext);
@@ -1975,6 +2104,8 @@ plperl_spi_execute_fetch_result(SPITupleTable *tuptable, int processed,
 {
 	HV		   *result;
 
+	check_spi_usage_allowed();
+
 	result = newHV();
 
 	hv_store_string(result, "status",
@@ -2148,6 +2279,8 @@ plperl_spi_query(char *query)
 	MemoryContext oldcontext = CurrentMemoryContext;
 	ResourceOwner oldowner = CurrentResourceOwner;
 
+	check_spi_usage_allowed();
+
 	BeginInternalSubTransaction(NULL);
 	/* Want to run inside function's memory context */
 	MemoryContextSwitchTo(oldcontext);
@@ -2226,6 +2359,8 @@ plperl_spi_fetchrow(char *cursor)
 	MemoryContext oldcontext = CurrentMemoryContext;
 	ResourceOwner oldowner = CurrentResourceOwner;
 
+	check_spi_usage_allowed();
+
 	BeginInternalSubTransaction(NULL);
 	/* Want to run inside function's memory context */
 	MemoryContextSwitchTo(oldcontext);
@@ -2300,7 +2435,11 @@ plperl_spi_fetchrow(char *cursor)
 void
 plperl_spi_cursor_close(char *cursor)
 {
-	Portal		p = SPI_cursor_find(cursor);
+	Portal		p;
+
+	check_spi_usage_allowed();
+
+	p = SPI_cursor_find(cursor);
 
 	if (p)
 		SPI_cursor_close(p);
@@ -2318,6 +2457,8 @@ plperl_spi_prepare(char *query, int argc, SV **argv)
 	MemoryContext oldcontext = CurrentMemoryContext;
 	ResourceOwner oldowner = CurrentResourceOwner;
 
+	check_spi_usage_allowed();
+
 	BeginInternalSubTransaction(NULL);
 	MemoryContextSwitchTo(oldcontext);
 
@@ -2453,6 +2594,8 @@ plperl_spi_exec_prepared(char *query, HV *attr, int argc, SV **argv)
 	MemoryContext oldcontext = CurrentMemoryContext;
 	ResourceOwner oldowner = CurrentResourceOwner;
 
+	check_spi_usage_allowed();
+
 	BeginInternalSubTransaction(NULL);
 	/* Want to run inside function's memory context */
 	MemoryContextSwitchTo(oldcontext);
@@ -2595,6 +2738,8 @@ plperl_spi_query_prepared(char *query, int argc, SV **argv)
 	MemoryContext oldcontext = CurrentMemoryContext;
 	ResourceOwner oldowner = CurrentResourceOwner;
 
+	check_spi_usage_allowed();
+
 	BeginInternalSubTransaction(NULL);
 	/* Want to run inside function's memory context */
 	MemoryContextSwitchTo(oldcontext);
@@ -2718,6 +2863,8 @@ plperl_spi_freeplan(char *query)
 	plperl_query_desc *qdesc;
 	plperl_query_entry *hash_entry;
 
+	check_spi_usage_allowed();
+
 	hash_entry = hash_search(plperl_query_hash, query,
 							 HASH_FIND, NULL);
 	if (hash_entry == NULL)
diff --git a/src/pl/plperl/sql/plperl_end.sql b/src/pl/plperl/sql/plperl_end.sql
new file mode 100644
index 00000000000..90f49dc6f97
--- /dev/null
+++ b/src/pl/plperl/sql/plperl_end.sql
@@ -0,0 +1,29 @@
+-- test END block handling
+
+-- Not included in the normal testing
+-- because it's beyond the scope of the test harness.
+-- Available here for manual developer testing.
+
+DO $do$
+	my $testlog = "/tmp/pgplperl_test.log";
+
+	warn "Run test, then examine contents of $testlog (which must already exist)\n";
+	return unless -f $testlog;
+
+    use IO::Handle; # for autoflush
+	open my $fh, '>', $testlog
+		or die "Can't write to $testlog: $!";
+    $fh->autoflush(1);
+
+    print $fh "# you should see just 3 'Warn: ...' lines: PRE, END and SPI ...\n";
+    $SIG{__WARN__} = sub { print $fh "Warn: @_" };
+    $SIG{__DIE__}  = sub { print $fh "Die: @_" unless $^S; die @_ };
+
+	END {
+		warn "END\n";
+		eval { spi_exec_query("select 1") };
+		warn $@;
+	}
+    warn "PRE\n";
+
+$do$ language plperlu;
diff --git a/src/pl/plperl/sql/plperl_plperlu.sql b/src/pl/plperl/sql/plperl_plperlu.sql
index fc2bb7b8067..15b5aa29687 100644
--- a/src/pl/plperl/sql/plperl_plperlu.sql
+++ b/src/pl/plperl/sql/plperl_plperlu.sql
@@ -16,4 +16,3 @@ $$ LANGUAGE plperlu; -- compile plperlu code
 SELECT * FROM bar(); -- throws exception normally (running plperl)
 SELECT * FROM foo(); -- used to cause backend crash (after switching to plperlu)
 
-