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Add a feature for automatic initialization and finalization of dynamically

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loaded libraries: call functions _PG_init() and _PG_fini() if the library
defines such symbols.  Hence we no longer need to specify an initialization
function in preload_libraries: we can assume that the library used the
_PG_init() convention, instead.  This removes one source of pilot error
in use of preloaded libraries.  Original patch by Ralf Engelschall,
preload_libraries changes by me.
This commit is contained in:
Tom Lane
2006-08-08 19:15:09 +00:00
parent e00664da48
commit b09bfcaa57
12 changed files with 179 additions and 239 deletions
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11
src/backend/postmaster/postmaster.c
View File

@@ -37,7 +37,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/postmaster/postmaster.c,v 1.497 2006/07/29 03:02:55 tgl Exp $
* $PostgreSQL: pgsql/src/backend/postmaster/postmaster.c,v 1.498 2006/08/08 19:15:07 tgl Exp $
*
* NOTES
*
@@ -197,9 +197,6 @@ bool Db_user_namespace = false;
char *bonjour_name;
/* list of library:init-function to be preloaded */
char *preload_libraries_string = NULL;
/* PIDs of special child processes; 0 when not running */
static pid_t StartupPID = 0,
BgWriterPID = 0,
@@ -710,11 +707,9 @@ PostmasterMain(int argc, char *argv[])
#endif
/*
* process any libraries that should be preloaded and optionally
* pre-initialized
* process any libraries that should be preloaded at postmaster start
*/
if (preload_libraries_string)
process_preload_libraries(preload_libraries_string);
process_preload_libraries();
/*
* Remove old temporary files. At this point there can be no other

27
src/backend/utils/fmgr/dfmgr.c
View File

@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/fmgr/dfmgr.c,v 1.86 2006/06/07 22:24:44 momjian Exp $
* $PostgreSQL: pgsql/src/backend/utils/fmgr/dfmgr.c,v 1.87 2006/08/08 19:15:08 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -25,6 +25,10 @@
#include "utils/dynamic_loader.h"
/* signatures for PostgreSQL-specific library init/fini functions */
typedef void (*PG_init_t)(void);
typedef void (*PG_fini_t)(void);
/*
* List of dynamically loaded files (kept in malloc'd memory).
*/
@@ -79,7 +83,7 @@ static const Pg_magic_struct magic_data = PG_MODULE_MAGIC_DATA;
* identifying the library file. The filehandle can be used with
* lookup_external_function to lookup additional functions in the same file
* at less cost than repeating load_external_function.
*/
*/
PGFunction
load_external_function(char *filename, char *funcname,
bool signalNotFound, void **filehandle)
@@ -90,6 +94,7 @@ load_external_function(char *filename, char *funcname,
char *load_error;
struct stat stat_buf;
char *fullname;
PG_init_t PG_init;
fullname = expand_dynamic_library_name(filename);
if (!fullname)
@@ -201,7 +206,14 @@ load_external_function(char *filename, char *funcname,
fullname),
errhint("Extension libraries are now required to use the PG_MODULE_MAGIC macro.")));
}
/*
* If the library has a _PG_init() function, call it.
*/
PG_init = (PG_init_t) pg_dlsym(file_scanner->handle, "_PG_init");
if (PG_init)
(*PG_init)();
/* OK to link it into list */
if (file_list == NULL)
file_list = file_scanner;
@@ -248,6 +260,7 @@ load_file(char *filename)
*nxt;
struct stat stat_buf;
char *fullname;
PG_fini_t PG_fini;
fullname = expand_dynamic_library_name(filename);
if (!fullname)
@@ -280,6 +293,14 @@ load_file(char *filename)
else
file_list = nxt;
clear_external_function_hash(file_scanner->handle);
/*
* If the library has a _PG_fini() function, call it.
*/
PG_fini = (PG_fini_t) pg_dlsym(file_scanner->handle, "_PG_fini");
if (PG_fini)
(*PG_fini)();
pg_dlclose(file_scanner->handle);
free((char *) file_scanner);
/* prv does not change */

60
src/backend/utils/init/miscinit.c
View File

@@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/utils/init/miscinit.c,v 1.155 2006/07/14 14:52:25 momjian Exp $
* $PostgreSQL: pgsql/src/backend/utils/init/miscinit.c,v 1.156 2006/08/08 19:15:08 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -1097,14 +1097,14 @@ ValidatePgVersion(const char *path)
*-------------------------------------------------------------------------
*/
typedef void (*func_ptr) ();
/* GUC variable: list of library names to be preloaded */
char *preload_libraries_string = NULL;
/*
* process any libraries that should be preloaded and
* optionally pre-initialized
* process any libraries that should be preloaded at postmaster start
*/
void
process_preload_libraries(char *preload_libraries_string)
process_preload_libraries(void)
{
char *rawstring;
List *elemlist;
@@ -1131,54 +1131,14 @@ process_preload_libraries(char *preload_libraries_string)
foreach(l, elemlist)
{
char *tok = (char *) lfirst(l);
char *sep = strstr(tok, ":");
char *filename = NULL;
char *funcname = NULL;
func_ptr initfunc;
if (sep)
{
/*
* a colon separator implies there is an initialization function
* that we need to run in addition to loading the library
*/
size_t filename_len = sep - tok;
size_t funcname_len = strlen(tok) - filename_len - 1;
filename = (char *) palloc(filename_len + 1);
memcpy(filename, tok, filename_len);
filename[filename_len] = '\0';
funcname = (char *) palloc(funcname_len + 1);
strcpy(funcname, sep + 1);
}
else
{
/*
* no separator -- just load the library
*/
filename = pstrdup(tok);
funcname = NULL;
}
char *filename;
filename = pstrdup(tok);
canonicalize_path(filename);
initfunc = (func_ptr) load_external_function(filename, funcname,
true, NULL);
if (initfunc)
(*initfunc) ();
if (funcname)
ereport(LOG,
(errmsg("preloaded library \"%s\" with initialization function \"%s\"",
filename, funcname)));
else
ereport(LOG,
(errmsg("preloaded library \"%s\"",
filename)));
(void) load_external_function(filename, NULL, true, NULL);
ereport(LOG,
(errmsg("preloaded library \"%s\"", filename)));
pfree(filename);
if (funcname)
pfree(funcname);
}
pfree(rawstring);