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/*-------------------------------------------------------------------------
*
* dfmgr.c
* Dynamic function manager code.
*
* Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/utils/fmgr/dfmgr.c,v 1.34 1999/09/28 11:27:13 vadim Exp $
*
*-------------------------------------------------------------------------
*/
#include <sys/types.h>
#include <sys/stat.h>
#include "postgres.h"
#include "utils/dynamic_loader.h"
#include "access/heapam.h"
#include "catalog/catname.h"
#include "catalog/pg_proc.h"
#include "dynloader.h"
#include "utils/builtins.h"
#include "utils/syscache.h"
static DynamicFileList *file_list = (DynamicFileList *) NULL;
static DynamicFileList *file_tail = (DynamicFileList *) NULL;
#define NOT_EQUAL(A, B) (((A).st_ino != (B).inode) \
|| ((A).st_dev != (B).device))
static Oid procedureId_save = -1;
static int pronargs_save;
static func_ptr user_fn_save = (func_ptr) NULL;
static func_ptr handle_load(char *filename, char *funcname);
func_ptr
fmgr_dynamic(Oid procedureId, int *pronargs)
{
HeapTuple procedureTuple;
Form_pg_proc procedureStruct;
char *proname,
*probinstring,
*prosrcstring,
*linksymbol;
Datum probinattr;
Datum prosrcattr;
func_ptr user_fn;
Relation rel;
bool isnull;
if (procedureId == procedureId_save)
{
*pronargs = pronargs_save;
return user_fn_save;
}
/*
* The procedure isn't a builtin, so we'll have to do a catalog lookup
* to find its pg_proc entry. Moreover, since probin is varlena, we're
* going to have to use heap_getattr, which means we need the reldesc,
* which means we need to open the relation. So we might as well do that
* first and get the benefit of SI inval if needed.
*/
rel = heap_openr(ProcedureRelationName, AccessShareLock);
procedureTuple = SearchSysCacheTuple(PROOID,
ObjectIdGetDatum(procedureId),
0, 0, 0);
if (!HeapTupleIsValid(procedureTuple))
{
elog(ERROR, "fmgr: Cache lookup failed for procedure %u\n",
procedureId);
return (func_ptr) NULL;
}
procedureStruct = (Form_pg_proc) GETSTRUCT(procedureTuple);
proname = procedureStruct->proname.data;
pronargs_save = *pronargs = procedureStruct->pronargs;
probinattr = heap_getattr(procedureTuple,
Anum_pg_proc_probin,
RelationGetDescr(rel), &isnull);
if (!PointerIsValid(probinattr) /* || isnull */ )
{
heap_close(rel, AccessShareLock);
elog(ERROR, "fmgr: Could not extract probin for %u from %s",
procedureId, ProcedureRelationName);
return (func_ptr) NULL;
}
probinstring = textout((struct varlena *) probinattr);
heap_close(rel, AccessShareLock);
prosrcattr = heap_getattr(procedureTuple,
Anum_pg_proc_prosrc,
RelationGetDescr(rel), &isnull);
if (isnull)
{ /* Use the proname for the link symbol */
linksymbol = proname;
}
else if (!PointerIsValid(prosrcattr))
{ /* pg_proc must be messed up! */
heap_close(rel, AccessShareLock);
elog(ERROR, "fmgr: Could not extract prosrc for %u from %s",
procedureId, ProcedureRelationName);
return (func_ptr) NULL;
}
else
{ /* The text in prosrcattr is either "-" or
* a link symbol */
prosrcstring = textout((struct varlena *) prosrcattr);
if (strcmp(prosrcstring, "-") == 0)
linksymbol = proname;
else
linksymbol = prosrcstring;
}
user_fn = handle_load(probinstring, linksymbol);
pfree(probinstring);
procedureId_save = procedureId;
user_fn_save = user_fn;
return user_fn;
}
static func_ptr
handle_load(char *filename, char *funcname)
{
DynamicFileList *file_scanner = (DynamicFileList *) NULL;
func_ptr retval = (func_ptr) NULL;
char *load_error;
struct stat stat_buf;
/*
* Do this because loading files may screw up the dynamic function
* manager otherwise.
*/
procedureId_save = -1;
/*
* Scan the list of loaded FILES to see if the function has been
* loaded.
*/
if (filename != (char *) NULL)
{
for (file_scanner = file_list;
file_scanner != (DynamicFileList *) NULL
&& file_scanner->filename != (char *) NULL
&& strcmp(filename, file_scanner->filename) != 0;
file_scanner = file_scanner->next)
;
if (file_scanner == (DynamicFileList *) NULL)
{
if (stat(filename, &stat_buf) == -1)
elog(ERROR, "stat failed on file '%s': %m", filename);
for (file_scanner = file_list;
file_scanner != (DynamicFileList *) NULL
&& (NOT_EQUAL(stat_buf, *file_scanner));
file_scanner = file_scanner->next)
;
/*
* Same files - different paths (ie, symlink or link)
*/
if (file_scanner != (DynamicFileList *) NULL)
strcpy(file_scanner->filename, filename);
}
}
else
file_scanner = (DynamicFileList *) NULL;
/*
* File not loaded yet.
*/
if (file_scanner == (DynamicFileList *) NULL)
{
if (file_list == (DynamicFileList *) NULL)
{
file_list = (DynamicFileList *)
malloc(sizeof(DynamicFileList));
file_scanner = file_list;
}
else
{
file_tail->next = (DynamicFileList *)
malloc(sizeof(DynamicFileList));
file_scanner = file_tail->next;
}
MemSet((char *) file_scanner, 0, sizeof(DynamicFileList));
strcpy(file_scanner->filename, filename);
file_scanner->device = stat_buf.st_dev;
file_scanner->inode = stat_buf.st_ino;
file_scanner->next = (DynamicFileList *) NULL;
file_scanner->handle = pg_dlopen(filename);
if (file_scanner->handle == (void *) NULL)
{
load_error = (char *) pg_dlerror();
if (file_scanner == file_list)
file_list = (DynamicFileList *) NULL;
else
file_tail->next = (DynamicFileList *) NULL;
free((char *) file_scanner);
elog(ERROR, "Load of file %s failed: %s", filename, load_error);
}
/*
* Just load the file - we are done with that so return.
*/
file_tail = file_scanner;
if (funcname == (char *) NULL)
return (func_ptr) NULL;
}
retval = (func_ptr) pg_dlsym(file_scanner->handle, funcname);
if (retval == (func_ptr) NULL)
elog(ERROR, "Can't find function %s in file %s", funcname, filename);
return retval;
}
/*
* This function loads files by the following:
*
* If the file is already loaded:
* o Zero out that file's loaded space (so it doesn't screw up linking)
* o Free all space associated with that file
* o Free that file's descriptor.
*
* Now load the file by calling handle_load with a NULL argument as the
* function.
*/
void
load_file(char *filename)
{
DynamicFileList *file_scanner,
*p;
struct stat stat_buf;
int done = 0;
/*
* We need to do stat() in order to determine whether this is the same
* file as a previously loaded file; it's also handy so as to give a
* good error message if bogus file name given.
*/
if (stat(filename, &stat_buf) == -1)
elog(ERROR, "LOAD: could not open file '%s': %m", filename);
if (file_list != (DynamicFileList *) NULL
&& !NOT_EQUAL(stat_buf, *file_list))
{
file_scanner = file_list;
file_list = file_list->next;
pg_dlclose(file_scanner->handle);
free((char *) file_scanner);
}
else if (file_list != (DynamicFileList *) NULL)
{
file_scanner = file_list;
while (!done)
{
if (file_scanner->next == (DynamicFileList *) NULL)
done = 1;
else if (!NOT_EQUAL(stat_buf, *(file_scanner->next)))
done = 1;
else
file_scanner = file_scanner->next;
}
if (file_scanner->next != (DynamicFileList *) NULL)
{
p = file_scanner->next;
file_scanner->next = file_scanner->next->next;
pg_dlclose(file_scanner->handle);
free((char *) p);
}
}
handle_load(filename, (char *) NULL);
}
/* Is this used? bjm 1998/10/08 No. tgl 1999/02/07 */
#ifdef NOT_USED
func_ptr
trigger_dynamic(char *filename, char *funcname)
{
func_ptr trigger_fn;
trigger_fn = handle_load(filename, funcname);
return trigger_fn;
}
#endif