Avoid passing function pointers across process boundaries.

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

1 files changed, 3 insertions, 3 deletions

diff --git a/src/include/fmgr.h b/src/include/fmgr.h
index 0c695e246a5..cfb7b7774df 100644
--- a/src/include/fmgr.h
+++ b/src/include/fmgr.h
@@ -657,7 +657,7 @@ extern bytea *OidSendFunctionCall(Oid functionId, Datum val);
 /*
  * Routines in fmgr.c
  */
-extern const Pg_finfo_record *fetch_finfo_record(void *filehandle, char *funcname);
+extern const Pg_finfo_record *fetch_finfo_record(void *filehandle, const char *funcname);
 extern void clear_external_function_hash(void *filehandle);
 extern Oid	fmgr_internal_function(const char *proname);
 extern Oid	get_fn_expr_rettype(FmgrInfo *flinfo);
@@ -673,9 +673,9 @@ extern bool CheckFunctionValidatorAccess(Oid validatorOid, Oid functionOid);
  */
 extern char *Dynamic_library_path;
 
-extern PGFunction load_external_function(char *filename, char *funcname,
+extern PGFunction load_external_function(const char *filename, const char *funcname,
 					   bool signalNotFound, void **filehandle);
-extern PGFunction lookup_external_function(void *filehandle, char *funcname);
+extern PGFunction lookup_external_function(void *filehandle, const char *funcname);
 extern void load_file(const char *filename, bool restricted);
 extern void **find_rendezvous_variable(const char *varName);
 extern Size EstimateLibraryStateSpace(void);