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65da0d66b4
Does not work since it fetches one byte beyond the source data, and when the phase of the moon is wrong, the source data is smack up against the end of backend memory and you get SIGSEGV. Don't laugh, this is a fix for an actual user bug report.
157 lines
2.7 KiB
C
157 lines
2.7 KiB
C
/*
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* misc_utils.c --
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*
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* This file defines miscellaneous PostgreSQL utility functions.
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*
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* Copyright (C) 1999, Massimo Dal Zotto <dz@cs.unitn.it>
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*
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* This file is distributed under the GNU General Public License
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* either version 2, or (at your option) any later version.
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*/
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#include <unistd.h>
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#include <signal.h>
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#include <string.h>
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#include <errno.h>
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#include "postgres.h"
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#include "access/heapam.h"
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#include "access/htup.h"
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#include "access/relscan.h"
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#include "access/skey.h"
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#include "access/tupdesc.h"
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#include "catalog/catname.h"
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#include "catalog/pg_listener.h"
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#include "fmgr.h"
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#include "storage/lmgr.h"
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#include "utils/fmgroids.h"
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#include "utils/palloc.h"
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#include "utils/rel.h"
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#include "utils/tqual.h"
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#include "misc_utils.h"
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#undef MIN
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#define MIN(x,y) ((x)<=(y) ? (x) : (y))
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extern int ExecutorLimit(int limit);
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extern void Async_Unlisten(char *relname, int pid);
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extern int assertTest(int val);
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#ifdef ASSERT_CHECKING_TEST
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extern int assertEnable(int val);
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#endif
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int
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query_limit(int limit)
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{
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return ExecutorLimit(limit);
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}
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int
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backend_pid()
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{
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return getpid();
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}
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int
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unlisten(char *relname)
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{
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Async_Unlisten(relname, getpid());
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return 0;
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}
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int
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max(int x, int y)
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{
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return ((x > y) ? x : y);
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}
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int
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min(int x, int y)
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{
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return ((x < y) ? x : y);
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}
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/*
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* Return the number of active listeners on a relation name.
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*/
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int
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active_listeners(text *relname)
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{
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HeapTuple lTuple;
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Relation lRel;
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HeapScanDesc sRel;
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TupleDesc tdesc;
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ScanKeyData key;
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Datum d;
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bool isnull;
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int len,
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pid;
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int count = 0;
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int ourpid = getpid();
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char listen_name[NAMEDATALEN];
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lRel = heap_openr(ListenerRelationName, AccessShareLock);
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tdesc = RelationGetDescr(lRel);
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if (relname && (VARSIZE(relname) > VARHDRSZ))
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{
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MemSet(listen_name, 0, NAMEDATALEN);
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len = MIN(VARSIZE(relname) - VARHDRSZ, NAMEDATALEN - 1);
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memcpy(listen_name, VARDATA(relname), len);
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ScanKeyEntryInitialize(&key, 0,
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Anum_pg_listener_relname,
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F_NAMEEQ,
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PointerGetDatum(listen_name));
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sRel = heap_beginscan(lRel, 0, SnapshotNow, 1, &key);
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}
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else
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sRel = heap_beginscan(lRel, 0, SnapshotNow, 0, (ScanKey) NULL);
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while (HeapTupleIsValid(lTuple = heap_getnext(sRel, 0)))
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{
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d = heap_getattr(lTuple, Anum_pg_listener_pid, tdesc, &isnull);
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pid = DatumGetInt32(d);
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if ((pid == ourpid) || (kill(pid, SIGTSTP) == 0))
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{
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/* elog(NOTICE, "%d ok", pid); */
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count++;
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}
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}
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heap_endscan(sRel);
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heap_close(lRel, AccessShareLock);
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return count;
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}
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#ifdef USE_ASSERT_CHECKING
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int
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assert_enable(int val)
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{
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return assertEnable(val);
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}
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#ifdef ASSERT_CHECKING_TEST
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int
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assert_test(int val)
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{
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return assertTest(val);
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}
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#endif
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#endif
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/* end of file */
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/*
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* Local Variables:
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* tab-width: 4
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* c-indent-level: 4
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* c-basic-offset: 4
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* End:
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*/
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