database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-11-24 00:23:06 +03:00
Code Activity

Avoid passing function pointers across process boundaries.

Browse Source 
We'd already recognized that we can't pass function pointers across process
boundaries for functions in loadable modules, since a shared library could
get loaded at different addresses in different processes.  But actually the
practice doesn't work for functions in the core backend either, if we're
using EXEC_BACKEND.  This is the cause of recent failures on buildfarm
member culicidae.  Switch to passing a string function name in all cases.

Something like this needs to be back-patched into 9.6, but let's see
if the buildfarm likes it first.

Petr Jelinek, with a bunch of basically-cosmetic adjustments by me

Discussion: https://postgr.es/m/548f9c1d-eafa-e3fa-9da8-f0cc2f654e60@2ndquadrant.com
This commit is contained in:
Tom Lane
2017-04-14 23:50:16 -04:00
parent 5a617ab3e6
commit 32470825d3
9 changed files with 187 additions and 149 deletions
Download Patch File Download Diff File Expand all files Collapse all files

15
src/backend/utils/fmgr/dfmgr.c
View File

@@ -91,7 +91,7 @@ static const Pg_magic_struct magic_data = PG_MODULE_MAGIC_DATA;
* at less cost than repeating load_external_function.
*/
PGFunction
load_external_function(char *filename, char *funcname,
load_external_function(const char *filename, const char *funcname,
bool signalNotFound, void **filehandle)
{
char *fullname;
@@ -108,8 +108,12 @@ load_external_function(char *filename, char *funcname,
if (filehandle)
*filehandle = lib_handle;
/* Look up the function within the library */
retval = (PGFunction) pg_dlsym(lib_handle, funcname);
/*
* Look up the function within the library. According to POSIX dlsym()
* should declare its second argument as "const char *", but older
* platforms might not, so for the time being we just cast away const.
*/
retval = (PGFunction) pg_dlsym(lib_handle, (char *) funcname);
if (retval == NULL && signalNotFound)
ereport(ERROR,
@@ -155,9 +159,10 @@ load_file(const char *filename, bool restricted)
* Return (PGFunction) NULL if not found.
*/
PGFunction
lookup_external_function(void *filehandle, char *funcname)
lookup_external_function(void *filehandle, const char *funcname)
{
return (PGFunction) pg_dlsym(filehandle, funcname);
/* as above, cast away const for the time being */
return (PGFunction) pg_dlsym(filehandle, (char *) funcname);
}