/src/postgres/src/backend/utils/fmgr/fmgr.c

Source
/*-------------------------------------------------------------------------
 *
 * fmgr.c
 *    The Postgres function manager.
 *
 * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *
 * IDENTIFICATION
 *    src/backend/utils/fmgr/fmgr.c
 *
 *-------------------------------------------------------------------------
 */

#include "postgres.h"

#include "access/detoast.h"
#include "access/htup_details.h"
#include "catalog/pg_language.h"
#include "catalog/pg_proc.h"
#include "catalog/pg_type.h"
#include "executor/functions.h"
#include "lib/stringinfo.h"
#include "miscadmin.h"
#include "nodes/makefuncs.h"
#include "nodes/miscnodes.h"
#include "nodes/nodeFuncs.h"
#include "pgstat.h"
#include "utils/acl.h"
#include "utils/builtins.h"
#include "utils/fmgrtab.h"
#include "utils/guc.h"
#include "utils/hsearch.h"
#include "utils/lsyscache.h"
#include "utils/syscache.h"

/*
 * Hooks for function calls
 */
PGDLLIMPORT needs_fmgr_hook_type needs_fmgr_hook = NULL;
PGDLLIMPORT fmgr_hook_type fmgr_hook = NULL;

/*
 * Hashtable for fast lookup of external C functions
 */
typedef struct
{
  /* fn_oid is the hash key and so must be first! */
  Oid     fn_oid;     /* OID of an external C function */
  TransactionId fn_xmin;    /* for checking up-to-dateness */
  ItemPointerData fn_tid;
  PGFunction  user_fn;    /* the function's address */
  const Pg_finfo_record *inforec; /* address of its info record */
} CFuncHashTabEntry;

static HTAB *CFuncHash = NULL;


static void fmgr_info_cxt_security(Oid functionId, FmgrInfo *finfo, MemoryContext mcxt,
                   bool ignore_security);
static void fmgr_info_C_lang(Oid functionId, FmgrInfo *finfo, HeapTuple procedureTuple);
static void fmgr_info_other_lang(Oid functionId, FmgrInfo *finfo, HeapTuple procedureTuple);
static CFuncHashTabEntry *lookup_C_func(HeapTuple procedureTuple);
static void record_C_func(HeapTuple procedureTuple,
              PGFunction user_fn, const Pg_finfo_record *inforec);

/* extern so it's callable via JIT */
extern Datum fmgr_security_definer(PG_FUNCTION_ARGS);


/*
 * Lookup routines for builtin-function table.  We can search by either Oid
 * or name, but search by Oid is much faster.
 */

static const FmgrBuiltin *
fmgr_isbuiltin(Oid id)
{
  uint16    index;

  /* fast lookup only possible if original oid still assigned */
  if (id > fmgr_last_builtin_oid)
    return NULL;

  /*
   * Lookup function data. If there's a miss in that range it's likely a
   * nonexistent function, returning NULL here will trigger an ERROR later.
   */
  index = fmgr_builtin_oid_index[id];
  if (index == InvalidOidBuiltinMapping)
    return NULL;

  return &fmgr_builtins[index];
}

/*
 * Lookup a builtin by name.  Note there can be more than one entry in
 * the array with the same name, but they should all point to the same
 * routine.
 */
static const FmgrBuiltin *
fmgr_lookupByName(const char *name)
{
  int     i;

  for (i = 0; i < fmgr_nbuiltins; i++)
  {
    if (strcmp(name, fmgr_builtins[i].funcName) == 0)
      return fmgr_builtins + i;
  }
  return NULL;
}

/*
 * This routine fills a FmgrInfo struct, given the OID
 * of the function to be called.
 *
 * The caller's CurrentMemoryContext is used as the fn_mcxt of the info
 * struct; this means that any subsidiary data attached to the info struct
 * (either by fmgr_info itself, or later on by a function call handler)
 * will be allocated in that context.  The caller must ensure that this
 * context is at least as long-lived as the info struct itself.  This is
 * not a problem in typical cases where the info struct is on the stack or
 * in freshly-palloc'd space.  However, if one intends to store an info
 * struct in a long-lived table, it's better to use fmgr_info_cxt.
 */
void
fmgr_info(Oid functionId, FmgrInfo *finfo)
{
  fmgr_info_cxt_security(functionId, finfo, CurrentMemoryContext, false);
}

/*
 * Fill a FmgrInfo struct, specifying a memory context in which its
 * subsidiary data should go.
 */
void
fmgr_info_cxt(Oid functionId, FmgrInfo *finfo, MemoryContext mcxt)
{
  fmgr_info_cxt_security(functionId, finfo, mcxt, false);
}

/*
 * This one does the actual work.  ignore_security is ordinarily false
 * but is set to true when we need to avoid recursion.
 */
static void
fmgr_info_cxt_security(Oid functionId, FmgrInfo *finfo, MemoryContext mcxt,
             bool ignore_security)
{
  const FmgrBuiltin *fbp;
  HeapTuple procedureTuple;
  Form_pg_proc procedureStruct;
  Datum   prosrcdatum;
  char     *prosrc;

  /*
   * fn_oid *must* be filled in last.  Some code assumes that if fn_oid is
   * valid, the whole struct is valid.  Some FmgrInfo struct's do survive
   * elogs.
   */
  finfo->fn_oid = InvalidOid;
  finfo->fn_extra = NULL;
  finfo->fn_mcxt = mcxt;
  finfo->fn_expr = NULL;   /* caller may set this later */

  if ((fbp = fmgr_isbuiltin(functionId)) != NULL)
  {
    /*
     * Fast path for builtin functions: don't bother consulting pg_proc
     */
    finfo->fn_nargs = fbp->nargs;
    finfo->fn_strict = fbp->strict;
    finfo->fn_retset = fbp->retset;
    finfo->fn_stats = TRACK_FUNC_ALL; /* ie, never track */
    finfo->fn_addr = fbp->func;
    finfo->fn_oid = functionId;
    return;
  }

  /* Otherwise we need the pg_proc entry */
  procedureTuple = SearchSysCache1(PROCOID, ObjectIdGetDatum(functionId));
  if (!HeapTupleIsValid(procedureTuple))
    elog(ERROR, "cache lookup failed for function %u", functionId);
  procedureStruct = (Form_pg_proc) GETSTRUCT(procedureTuple);

  finfo->fn_nargs = procedureStruct->pronargs;
  finfo->fn_strict = procedureStruct->proisstrict;
  finfo->fn_retset = procedureStruct->proretset;

  /*
   * If it has prosecdef set, non-null proconfig, or if a plugin wants to
   * hook function entry/exit, use fmgr_security_definer call handler ---
   * unless we are being called again by fmgr_security_definer or
   * fmgr_info_other_lang.
   *
   * When using fmgr_security_definer, function stats tracking is always
   * disabled at the outer level, and instead we set the flag properly in
   * fmgr_security_definer's private flinfo and implement the tracking
   * inside fmgr_security_definer.  This loses the ability to charge the
   * overhead of fmgr_security_definer to the function, but gains the
   * ability to set the track_functions GUC as a local GUC parameter of an
   * interesting function and have the right things happen.
   */
  if (!ignore_security &&
    (procedureStruct->prosecdef ||
     !heap_attisnull(procedureTuple, Anum_pg_proc_proconfig, NULL) ||
     FmgrHookIsNeeded(functionId)))
  {
    finfo->fn_addr = fmgr_security_definer;
    finfo->fn_stats = TRACK_FUNC_ALL; /* ie, never track */
    finfo->fn_oid = functionId;
    ReleaseSysCache(procedureTuple);
    return;
  }

  switch (procedureStruct->prolang)
  {
    case INTERNALlanguageId:

      /*
       * For an ordinary builtin function, we should never get here
       * because the fmgr_isbuiltin() search above will have succeeded.
       * However, if the user has done a CREATE FUNCTION to create an
       * alias for a builtin function, we can end up here.  In that case
       * we have to look up the function by name.  The name of the
       * internal function is stored in prosrc (it doesn't have to be
       * the same as the name of the alias!)
       */
      prosrcdatum = SysCacheGetAttrNotNull(PROCOID, procedureTuple,
                         Anum_pg_proc_prosrc);
      prosrc = TextDatumGetCString(prosrcdatum);
      fbp = fmgr_lookupByName(prosrc);
      if (fbp == NULL)
        ereport(ERROR,
            (errcode(ERRCODE_UNDEFINED_FUNCTION),
             errmsg("internal function \"%s\" is not in internal lookup table",
                prosrc)));
      pfree(prosrc);
      /* Should we check that nargs, strict, retset match the table? */
      finfo->fn_addr = fbp->func;
      /* note this policy is also assumed in fast path above */
      finfo->fn_stats = TRACK_FUNC_ALL; /* ie, never track */
      break;

    case ClanguageId:
      fmgr_info_C_lang(functionId, finfo, procedureTuple);
      finfo->fn_stats = TRACK_FUNC_PL;  /* ie, track if ALL */
      break;

    case SQLlanguageId:
      finfo->fn_addr = fmgr_sql;
      finfo->fn_stats = TRACK_FUNC_PL;  /* ie, track if ALL */
      break;

    default:
      fmgr_info_other_lang(functionId, finfo, procedureTuple);
      finfo->fn_stats = TRACK_FUNC_OFF; /* ie, track if not OFF */
      break;
  }

  finfo->fn_oid = functionId;
  ReleaseSysCache(procedureTuple);
}

/*
 * Return module and C function name providing implementation of functionId.
 *
 * If *mod == NULL and *fn == NULL, no C symbol is known to implement
 * function.
 *
 * If *mod == NULL and *fn != NULL, the function is implemented by a symbol in
 * the main binary.
 *
 * If *mod != NULL and *fn != NULL the function is implemented in an extension
 * shared object.
 *
 * The returned module and function names are pstrdup'ed into the current
 * memory context.
 */
void
fmgr_symbol(Oid functionId, char **mod, char **fn)
{
  HeapTuple procedureTuple;
  Form_pg_proc procedureStruct;
  Datum   prosrcattr;
  Datum   probinattr;

  procedureTuple = SearchSysCache1(PROCOID, ObjectIdGetDatum(functionId));
  if (!HeapTupleIsValid(procedureTuple))
    elog(ERROR, "cache lookup failed for function %u", functionId);
  procedureStruct = (Form_pg_proc) GETSTRUCT(procedureTuple);

  if (procedureStruct->prosecdef ||
    !heap_attisnull(procedureTuple, Anum_pg_proc_proconfig, NULL) ||
    FmgrHookIsNeeded(functionId))
  {
    *mod = NULL;     /* core binary */
    *fn = pstrdup("fmgr_security_definer");
    ReleaseSysCache(procedureTuple);
    return;
  }

  /* see fmgr_info_cxt_security for the individual cases */
  switch (procedureStruct->prolang)
  {
    case INTERNALlanguageId:
      prosrcattr = SysCacheGetAttrNotNull(PROCOID, procedureTuple,
                        Anum_pg_proc_prosrc);

      *mod = NULL;   /* core binary */
      *fn = TextDatumGetCString(prosrcattr);
      break;

    case ClanguageId:
      prosrcattr = SysCacheGetAttrNotNull(PROCOID, procedureTuple,
                        Anum_pg_proc_prosrc);

      probinattr = SysCacheGetAttrNotNull(PROCOID, procedureTuple,
                        Anum_pg_proc_probin);

      /*
       * No need to check symbol presence / API version here, already
       * checked in fmgr_info_cxt_security.
       */
      *mod = TextDatumGetCString(probinattr);
      *fn = TextDatumGetCString(prosrcattr);
      break;

    case SQLlanguageId:
      *mod = NULL;   /* core binary */
      *fn = pstrdup("fmgr_sql");
      break;

    default:
      *mod = NULL;
      *fn = NULL;     /* unknown, pass pointer */
      break;
  }

  ReleaseSysCache(procedureTuple);
}


/*
 * Special fmgr_info processing for C-language functions.  Note that
 * finfo->fn_oid is not valid yet.
 */
static void
fmgr_info_C_lang(Oid functionId, FmgrInfo *finfo, HeapTuple procedureTuple)
{
  CFuncHashTabEntry *hashentry;
  PGFunction  user_fn;
  const Pg_finfo_record *inforec;

  /*
   * See if we have the function address cached already
   */
  hashentry = lookup_C_func(procedureTuple);
  if (hashentry)
  {
    user_fn = hashentry->user_fn;
    inforec = hashentry->inforec;
  }
  else
  {
    Datum   prosrcattr,
          probinattr;
    char     *prosrcstring,
           *probinstring;
    void     *libraryhandle;

    /*
     * Get prosrc and probin strings (link symbol and library filename).
     * While in general these columns might be null, that's not allowed
     * for C-language functions.
     */
    prosrcattr = SysCacheGetAttrNotNull(PROCOID, procedureTuple,
                      Anum_pg_proc_prosrc);
    prosrcstring = TextDatumGetCString(prosrcattr);

    probinattr = SysCacheGetAttrNotNull(PROCOID, procedureTuple,
                      Anum_pg_proc_probin);
    probinstring = TextDatumGetCString(probinattr);

    /* Look up the function itself */
    user_fn = load_external_function(probinstring, prosrcstring, true,
                     &libraryhandle);

    /* Get the function information record (real or default) */
    inforec = fetch_finfo_record(libraryhandle, prosrcstring);

    /* Cache the addresses for later calls */
    record_C_func(procedureTuple, user_fn, inforec);

    pfree(prosrcstring);
    pfree(probinstring);
  }

  switch (inforec->api_version)
  {
    case 1:
      /* New style: call directly */
      finfo->fn_addr = user_fn;
      break;
    default:
      /* Shouldn't get here if fetch_finfo_record did its job */
      elog(ERROR, "unrecognized function API version: %d",
         inforec->api_version);
      break;
  }
}

/*
 * Special fmgr_info processing for other-language functions.  Note
 * that finfo->fn_oid is not valid yet.
 */
static void
fmgr_info_other_lang(Oid functionId, FmgrInfo *finfo, HeapTuple procedureTuple)
{
  Form_pg_proc procedureStruct = (Form_pg_proc) GETSTRUCT(procedureTuple);
  Oid     language = procedureStruct->prolang;
  HeapTuple languageTuple;
  Form_pg_language languageStruct;
  FmgrInfo  plfinfo;

  languageTuple = SearchSysCache1(LANGOID, ObjectIdGetDatum(language));
  if (!HeapTupleIsValid(languageTuple))
    elog(ERROR, "cache lookup failed for language %u", language);
  languageStruct = (Form_pg_language) GETSTRUCT(languageTuple);

  /*
   * Look up the language's call handler function, ignoring any attributes
   * that would normally cause insertion of fmgr_security_definer.  We need
   * to get back a bare pointer to the actual C-language function.
   */
  fmgr_info_cxt_security(languageStruct->lanplcallfoid, &plfinfo,
               CurrentMemoryContext, true);
  finfo->fn_addr = plfinfo.fn_addr;

  ReleaseSysCache(languageTuple);
}

/*
 * Fetch and validate the information record for the given external function.
 * The function is specified by a handle for the containing library
 * (obtained from load_external_function) as well as the function name.
 *
 * If no info function exists for the given name an error is raised.
 *
 * This function is broken out of fmgr_info_C_lang so that fmgr_c_validator
 * can validate the information record for a function not yet entered into
 * pg_proc.
 */
const Pg_finfo_record *
fetch_finfo_record(void *filehandle, const char *funcname)
{
  char     *infofuncname;
  PGFInfoFunction infofunc;
  const Pg_finfo_record *inforec;

  infofuncname = psprintf("pg_finfo_%s", funcname);

  /* Try to look up the info function */
  infofunc = (PGFInfoFunction) lookup_external_function(filehandle,
                              infofuncname);
  if (infofunc == NULL)
  {
    ereport(ERROR,
        (errcode(ERRCODE_UNDEFINED_FUNCTION),
         errmsg("could not find function information for function \"%s\"",
            funcname),
         errhint("SQL-callable functions need an accompanying PG_FUNCTION_INFO_V1(funcname).")));
    return NULL;     /* silence compiler */
  }

  /* Found, so call it */
  inforec = (*infofunc) ();

  /* Validate result as best we can */
  if (inforec == NULL)
    elog(ERROR, "null result from info function \"%s\"", infofuncname);
  switch (inforec->api_version)
  {
    case 1:
      /* OK, no additional fields to validate */
      break;
    default:
      ereport(ERROR,
          (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
           errmsg("unrecognized API version %d reported by info function \"%s\"",
              inforec->api_version, infofuncname)));
      break;
  }

  pfree(infofuncname);
  return inforec;
}


/*-------------------------------------------------------------------------
 *    Routines for caching lookup information for external C functions.
 *
 * The routines in dfmgr.c are relatively slow, so we try to avoid running
 * them more than once per external function per session.  We use a hash table
 * with the function OID as the lookup key.
 *-------------------------------------------------------------------------
 */

/*
 * lookup_C_func: try to find a C function in the hash table
 *
 * If an entry exists and is up to date, return it; else return NULL
 */
static CFuncHashTabEntry *
lookup_C_func(HeapTuple procedureTuple)
{
  Oid     fn_oid = ((Form_pg_proc) GETSTRUCT(procedureTuple))->oid;
  CFuncHashTabEntry *entry;

  if (CFuncHash == NULL)
    return NULL;     /* no table yet */
  entry = (CFuncHashTabEntry *)
    hash_search(CFuncHash,
          &fn_oid,
          HASH_FIND,
          NULL);
  if (entry == NULL)
    return NULL;     /* no such entry */
  if (entry->fn_xmin == HeapTupleHeaderGetRawXmin(procedureTuple->t_data) &&
    ItemPointerEquals(&entry->fn_tid, &procedureTuple->t_self))
    return entry;     /* OK */
  return NULL;       /* entry is out of date */
}

/*
 * record_C_func: enter (or update) info about a C function in the hash table
 */
static void
record_C_func(HeapTuple procedureTuple,
        PGFunction user_fn, const Pg_finfo_record *inforec)
{
  Oid     fn_oid = ((Form_pg_proc) GETSTRUCT(procedureTuple))->oid;
  CFuncHashTabEntry *entry;
  bool    found;

  /* Create the hash table if it doesn't exist yet */
  if (CFuncHash == NULL)
  {
    HASHCTL   hash_ctl;

    hash_ctl.keysize = sizeof(Oid);
    hash_ctl.entrysize = sizeof(CFuncHashTabEntry);
    CFuncHash = hash_create("CFuncHash",
                100,
                &hash_ctl,
                HASH_ELEM | HASH_BLOBS);
  }

  entry = (CFuncHashTabEntry *)
    hash_search(CFuncHash,
          &fn_oid,
          HASH_ENTER,
          &found);
  /* OID is already filled in */
  entry->fn_xmin = HeapTupleHeaderGetRawXmin(procedureTuple->t_data);
  entry->fn_tid = procedureTuple->t_self;
  entry->user_fn = user_fn;
  entry->inforec = inforec;
}


/*
 * Copy an FmgrInfo struct
 *
 * This is inherently somewhat bogus since we can't reliably duplicate
 * language-dependent subsidiary info.  We cheat by zeroing fn_extra,
 * instead, meaning that subsidiary info will have to be recomputed.
 */
void
fmgr_info_copy(FmgrInfo *dstinfo, FmgrInfo *srcinfo,
         MemoryContext destcxt)
{
  memcpy(dstinfo, srcinfo, sizeof(FmgrInfo));
  dstinfo->fn_mcxt = destcxt;
  dstinfo->fn_extra = NULL;
}


/*
 * Specialized lookup routine for fmgr_internal_validator: given the alleged
 * name of an internal function, return the OID of the function.
 * If the name is not recognized, return InvalidOid.
 */
Oid
fmgr_internal_function(const char *proname)
{
  const FmgrBuiltin *fbp = fmgr_lookupByName(proname);

  if (fbp == NULL)
    return InvalidOid;
  return fbp->foid;
}


/*
 * Support for security-definer and proconfig-using functions.  We support
 * both of these features using the same call handler, because they are
 * often used together and it would be inefficient (as well as notationally
 * messy) to have two levels of call handler involved.
 */
struct fmgr_security_definer_cache
{
  FmgrInfo  flinfo;     /* lookup info for target function */
  Oid     userid;     /* userid to set, or InvalidOid */
  List     *configNames;  /* GUC names to set, or NIL */
  List     *configHandles;  /* GUC handles to set, or NIL */
  List     *configValues; /* GUC values to set, or NIL */
  Datum   arg;      /* passthrough argument for plugin modules */
};

/*
 * Function handler for security-definer/proconfig/plugin-hooked functions.
 * We extract the OID of the actual function and do a fmgr lookup again.
 * Then we fetch the pg_proc row and copy the owner ID and proconfig fields.
 * (All this info is cached for the duration of the current query.)
 * To execute a call, we temporarily replace the flinfo with the cached
 * and looked-up one, while keeping the outer fcinfo (which contains all
 * the actual arguments, etc.) intact.  This is not re-entrant, but then
 * the fcinfo itself can't be used reentrantly anyway.
 */
extern Datum
fmgr_security_definer(PG_FUNCTION_ARGS)
{
  Datum   result;
  struct fmgr_security_definer_cache *volatile fcache;
  FmgrInfo   *save_flinfo;
  Oid     save_userid;
  int     save_sec_context;
  ListCell   *lc1,
         *lc2,
         *lc3;
  int     save_nestlevel;
  PgStat_FunctionCallUsage fcusage;

  if (!fcinfo->flinfo->fn_extra)
  {
    HeapTuple tuple;
    Form_pg_proc procedureStruct;
    Datum   datum;
    bool    isnull;
    MemoryContext oldcxt;

    fcache = MemoryContextAllocZero(fcinfo->flinfo->fn_mcxt,
                    sizeof(*fcache));

    fmgr_info_cxt_security(fcinfo->flinfo->fn_oid, &fcache->flinfo,
                 fcinfo->flinfo->fn_mcxt, true);
    fcache->flinfo.fn_expr = fcinfo->flinfo->fn_expr;

    tuple = SearchSysCache1(PROCOID,
                ObjectIdGetDatum(fcinfo->flinfo->fn_oid));
    if (!HeapTupleIsValid(tuple))
      elog(ERROR, "cache lookup failed for function %u",
         fcinfo->flinfo->fn_oid);
    procedureStruct = (Form_pg_proc) GETSTRUCT(tuple);

    if (procedureStruct->prosecdef)
      fcache->userid = procedureStruct->proowner;

    datum = SysCacheGetAttr(PROCOID, tuple, Anum_pg_proc_proconfig,
                &isnull);
    if (!isnull)
    {
      ArrayType  *array;
      ListCell   *lc;

      oldcxt = MemoryContextSwitchTo(fcinfo->flinfo->fn_mcxt);
      array = DatumGetArrayTypeP(datum);
      TransformGUCArray(array, &fcache->configNames,
                &fcache->configValues);

      /* transform names to config handles to avoid lookup cost */
      fcache->configHandles = NIL;
      foreach(lc, fcache->configNames)
      {
        char     *name = (char *) lfirst(lc);

        fcache->configHandles = lappend(fcache->configHandles,
                        get_config_handle(name));
      }

      MemoryContextSwitchTo(oldcxt);
    }

    ReleaseSysCache(tuple);

    fcinfo->flinfo->fn_extra = fcache;
  }
  else
    fcache = fcinfo->flinfo->fn_extra;

  /* GetUserIdAndSecContext is cheap enough that no harm in a wasted call */
  GetUserIdAndSecContext(&save_userid, &save_sec_context);
  if (fcache->configNames != NIL) /* Need a new GUC nesting level */
    save_nestlevel = NewGUCNestLevel();
  else
    save_nestlevel = 0;   /* keep compiler quiet */

  if (OidIsValid(fcache->userid))
    SetUserIdAndSecContext(fcache->userid,
                 save_sec_context | SECURITY_LOCAL_USERID_CHANGE);

  forthree(lc1, fcache->configNames,
       lc2, fcache->configHandles,
       lc3, fcache->configValues)
  {
    GucContext  context = superuser() ? PGC_SUSET : PGC_USERSET;
    GucSource source = PGC_S_SESSION;
    GucAction action = GUC_ACTION_SAVE;
    char     *name = lfirst(lc1);
    config_handle *handle = lfirst(lc2);
    char     *value = lfirst(lc3);

    (void) set_config_with_handle(name, handle, value,
                    context, source, GetUserId(),
                    action, true, 0, false);
  }

  /* function manager hook */
  if (fmgr_hook)
    (*fmgr_hook) (FHET_START, &fcache->flinfo, &fcache->arg);

  /*
   * We don't need to restore GUC or userid settings on error, because the
   * ensuing xact or subxact abort will do that.  The PG_TRY block is only
   * needed to clean up the flinfo link.
   */
  save_flinfo = fcinfo->flinfo;

  PG_TRY();
  {
    fcinfo->flinfo = &fcache->flinfo;

    /* See notes in fmgr_info_cxt_security */
    pgstat_init_function_usage(fcinfo, &fcusage);

    result = FunctionCallInvoke(fcinfo);

    /*
     * We could be calling either a regular or a set-returning function,
     * so we have to test to see what finalize flag to use.
     */
    pgstat_end_function_usage(&fcusage,
                  (fcinfo->resultinfo == NULL ||
                   !IsA(fcinfo->resultinfo, ReturnSetInfo) ||
                   ((ReturnSetInfo *) fcinfo->resultinfo)->isDone != ExprMultipleResult));
  }
  PG_CATCH();
  {
    fcinfo->flinfo = save_flinfo;
    if (fmgr_hook)
      (*fmgr_hook) (FHET_ABORT, &fcache->flinfo, &fcache->arg);
    PG_RE_THROW();
  }
  PG_END_TRY();

  fcinfo->flinfo = save_flinfo;

  if (fcache->configNames != NIL)
    AtEOXact_GUC(true, save_nestlevel);
  if (OidIsValid(fcache->userid))
    SetUserIdAndSecContext(save_userid, save_sec_context);
  if (fmgr_hook)
    (*fmgr_hook) (FHET_END, &fcache->flinfo, &fcache->arg);

  return result;
}


/*-------------------------------------------------------------------------
 *    Support routines for callers of fmgr-compatible functions
 *-------------------------------------------------------------------------
 */

/*
 * These are for invocation of a specifically named function with a
 * directly-computed parameter list.  Note that neither arguments nor result
 * are allowed to be NULL.  Also, the function cannot be one that needs to
 * look at FmgrInfo, since there won't be any.
 */
Datum
DirectFunctionCall1Coll(PGFunction func, Oid collation, Datum arg1)
{
  LOCAL_FCINFO(fcinfo, 1);
  Datum   result;

  InitFunctionCallInfoData(*fcinfo, NULL, 1, collation, NULL, NULL);

  fcinfo->args[0].value = arg1;
  fcinfo->args[0].isnull = false;

  result = (*func) (fcinfo);

  /* Check for null result, since caller is clearly not expecting one */
  if (fcinfo->isnull)
    elog(ERROR, "function %p returned NULL", (void *) func);

  return result;
}

Datum
DirectFunctionCall2Coll(PGFunction func, Oid collation, Datum arg1, Datum arg2)
{
  LOCAL_FCINFO(fcinfo, 2);
  Datum   result;

  InitFunctionCallInfoData(*fcinfo, NULL, 2, collation, NULL, NULL);

  fcinfo->args[0].value = arg1;
  fcinfo->args[0].isnull = false;
  fcinfo->args[1].value = arg2;
  fcinfo->args[1].isnull = false;

  result = (*func) (fcinfo);

  /* Check for null result, since caller is clearly not expecting one */
  if (fcinfo->isnull)
    elog(ERROR, "function %p returned NULL", (void *) func);

  return result;
}

Datum
DirectFunctionCall3Coll(PGFunction func, Oid collation, Datum arg1, Datum arg2,
            Datum arg3)
{
  LOCAL_FCINFO(fcinfo, 3);
  Datum   result;

  InitFunctionCallInfoData(*fcinfo, NULL, 3, collation, NULL, NULL);

  fcinfo->args[0].value = arg1;
  fcinfo->args[0].isnull = false;
  fcinfo->args[1].value = arg2;
  fcinfo->args[1].isnull = false;
  fcinfo->args[2].value = arg3;
  fcinfo->args[2].isnull = false;

  result = (*func) (fcinfo);

  /* Check for null result, since caller is clearly not expecting one */
  if (fcinfo->isnull)
    elog(ERROR, "function %p returned NULL", (void *) func);

  return result;
}

Datum
DirectFunctionCall4Coll(PGFunction func, Oid collation, Datum arg1, Datum arg2,
            Datum arg3, Datum arg4)
{
  LOCAL_FCINFO(fcinfo, 4);
  Datum   result;

  InitFunctionCallInfoData(*fcinfo, NULL, 4, collation, NULL, NULL);

  fcinfo->args[0].value = arg1;
  fcinfo->args[0].isnull = false;
  fcinfo->args[1].value = arg2;
  fcinfo->args[1].isnull = false;
  fcinfo->args[2].value = arg3;
  fcinfo->args[2].isnull = false;
  fcinfo->args[3].value = arg4;
  fcinfo->args[3].isnull = false;

  result = (*func) (fcinfo);

  /* Check for null result, since caller is clearly not expecting one */
  if (fcinfo->isnull)
    elog(ERROR, "function %p returned NULL", (void *) func);

  return result;
}

Datum
DirectFunctionCall5Coll(PGFunction func, Oid collation, Datum arg1, Datum arg2,
            Datum arg3, Datum arg4, Datum arg5)
{
  LOCAL_FCINFO(fcinfo, 5);
  Datum   result;

  InitFunctionCallInfoData(*fcinfo, NULL, 5, collation, NULL, NULL);

  fcinfo->args[0].value = arg1;
  fcinfo->args[0].isnull = false;
  fcinfo->args[1].value = arg2;
  fcinfo->args[1].isnull = false;
  fcinfo->args[2].value = arg3;
  fcinfo->args[2].isnull = false;
  fcinfo->args[3].value = arg4;
  fcinfo->args[3].isnull = false;
  fcinfo->args[4].value = arg5;
  fcinfo->args[4].isnull = false;

  result = (*func) (fcinfo);

  /* Check for null result, since caller is clearly not expecting one */
  if (fcinfo->isnull)
    elog(ERROR, "function %p returned NULL", (void *) func);

  return result;
}

Datum
DirectFunctionCall6Coll(PGFunction func, Oid collation, Datum arg1, Datum arg2,
            Datum arg3, Datum arg4, Datum arg5,
            Datum arg6)
{
  LOCAL_FCINFO(fcinfo, 6);
  Datum   result;

  InitFunctionCallInfoData(*fcinfo, NULL, 6, collation, NULL, NULL);

  fcinfo->args[0].value = arg1;
  fcinfo->args[0].isnull = false;
  fcinfo->args[1].value = arg2;
  fcinfo->args[1].isnull = false;
  fcinfo->args[2].value = arg3;
  fcinfo->args[2].isnull = false;
  fcinfo->args[3].value = arg4;
  fcinfo->args[3].isnull = false;
  fcinfo->args[4].value = arg5;
  fcinfo->args[4].isnull = false;
  fcinfo->args[5].value = arg6;
  fcinfo->args[5].isnull = false;

  result = (*func) (fcinfo);

  /* Check for null result, since caller is clearly not expecting one */
  if (fcinfo->isnull)
    elog(ERROR, "function %p returned NULL", (void *) func);

  return result;
}

Datum
DirectFunctionCall7Coll(PGFunction func, Oid collation, Datum arg1, Datum arg2,
            Datum arg3, Datum arg4, Datum arg5,
            Datum arg6, Datum arg7)
{
  LOCAL_FCINFO(fcinfo, 7);
  Datum   result;

  InitFunctionCallInfoData(*fcinfo, NULL, 7, collation, NULL, NULL);

  fcinfo->args[0].value = arg1;
  fcinfo->args[0].isnull = false;
  fcinfo->args[1].value = arg2;
  fcinfo->args[1].isnull = false;
  fcinfo->args[2].value = arg3;
  fcinfo->args[2].isnull = false;
  fcinfo->args[3].value = arg4;
  fcinfo->args[3].isnull = false;
  fcinfo->args[4].value = arg5;
  fcinfo->args[4].isnull = false;
  fcinfo->args[5].value = arg6;
  fcinfo->args[5].isnull = false;
  fcinfo->args[6].value = arg7;
  fcinfo->args[6].isnull = false;

  result = (*func) (fcinfo);

  /* Check for null result, since caller is clearly not expecting one */
  if (fcinfo->isnull)
    elog(ERROR, "function %p returned NULL", (void *) func);

  return result;
}

Datum
DirectFunctionCall8Coll(PGFunction func, Oid collation, Datum arg1, Datum arg2,
            Datum arg3, Datum arg4, Datum arg5,
            Datum arg6, Datum arg7, Datum arg8)
{
  LOCAL_FCINFO(fcinfo, 8);
  Datum   result;

  InitFunctionCallInfoData(*fcinfo, NULL, 8, collation, NULL, NULL);

  fcinfo->args[0].value = arg1;
  fcinfo->args[0].isnull = false;
  fcinfo->args[1].value = arg2;
  fcinfo->args[1].isnull = false;
  fcinfo->args[2].value = arg3;
  fcinfo->args[2].isnull = false;
  fcinfo->args[3].value = arg4;
  fcinfo->args[3].isnull = false;
  fcinfo->args[4].value = arg5;
  fcinfo->args[4].isnull = false;
  fcinfo->args[5].value = arg6;
  fcinfo->args[5].isnull = false;
  fcinfo->args[6].value = arg7;
  fcinfo->args[6].isnull = false;
  fcinfo->args[7].value = arg8;
  fcinfo->args[7].isnull = false;

  result = (*func) (fcinfo);

  /* Check for null result, since caller is clearly not expecting one */
  if (fcinfo->isnull)
    elog(ERROR, "function %p returned NULL", (void *) func);

  return result;
}

Datum
DirectFunctionCall9Coll(PGFunction func, Oid collation, Datum arg1, Datum arg2,
            Datum arg3, Datum arg4, Datum arg5,
            Datum arg6, Datum arg7, Datum arg8,
            Datum arg9)
{
  LOCAL_FCINFO(fcinfo, 9);
  Datum   result;

  InitFunctionCallInfoData(*fcinfo, NULL, 9, collation, NULL, NULL);

  fcinfo->args[0].value = arg1;
  fcinfo->args[0].isnull = false;
  fcinfo->args[1].value = arg2;
  fcinfo->args[1].isnull = false;
  fcinfo->args[2].value = arg3;
  fcinfo->args[2].isnull = false;
  fcinfo->args[3].value = arg4;
  fcinfo->args[3].isnull = false;
  fcinfo->args[4].value = arg5;
  fcinfo->args[4].isnull = false;
  fcinfo->args[5].value = arg6;
  fcinfo->args[5].isnull = false;
  fcinfo->args[6].value = arg7;
  fcinfo->args[6].isnull = false;
  fcinfo->args[7].value = arg8;
  fcinfo->args[7].isnull = false;
  fcinfo->args[8].value = arg9;
  fcinfo->args[8].isnull = false;

  result = (*func) (fcinfo);

  /* Check for null result, since caller is clearly not expecting one */
  if (fcinfo->isnull)
    elog(ERROR, "function %p returned NULL", (void *) func);

  return result;
}

/*
 * These functions work like the DirectFunctionCall functions except that
 * they use the flinfo parameter to initialise the fcinfo for the call.
 * It's recommended that the callee only use the fn_extra and fn_mcxt
 * fields, as other fields will typically describe the calling function
 * not the callee.  Conversely, the calling function should not have
 * used fn_extra, unless its use is known to be compatible with the callee's.
 */

Datum
CallerFInfoFunctionCall1(PGFunction func, FmgrInfo *flinfo, Oid collation, Datum arg1)
{
  LOCAL_FCINFO(fcinfo, 1);
  Datum   result;

  InitFunctionCallInfoData(*fcinfo, flinfo, 1, collation, NULL, NULL);

  fcinfo->args[0].value = arg1;
  fcinfo->args[0].isnull = false;

  result = (*func) (fcinfo);

  /* Check for null result, since caller is clearly not expecting one */
  if (fcinfo->isnull)
    elog(ERROR, "function %p returned NULL", (void *) func);

  return result;
}

Datum
CallerFInfoFunctionCall2(PGFunction func, FmgrInfo *flinfo, Oid collation, Datum arg1, Datum arg2)
{
  LOCAL_FCINFO(fcinfo, 2);
  Datum   result;

  InitFunctionCallInfoData(*fcinfo, flinfo, 2, collation, NULL, NULL);

  fcinfo->args[0].value = arg1;
  fcinfo->args[0].isnull = false;
  fcinfo->args[1].value = arg2;
  fcinfo->args[1].isnull = false;

  result = (*func) (fcinfo);

  /* Check for null result, since caller is clearly not expecting one */
  if (fcinfo->isnull)
    elog(ERROR, "function %p returned NULL", (void *) func);

  return result;
}

/*
 * These are for invocation of a previously-looked-up function with a
 * directly-computed parameter list.  Note that neither arguments nor result
 * are allowed to be NULL.
 */
Datum
FunctionCall0Coll(FmgrInfo *flinfo, Oid collation)
{
  LOCAL_FCINFO(fcinfo, 0);
  Datum   result;

  InitFunctionCallInfoData(*fcinfo, flinfo, 0, collation, NULL, NULL);

  result = FunctionCallInvoke(fcinfo);

  /* Check for null result, since caller is clearly not expecting one */
  if (fcinfo->isnull)
    elog(ERROR, "function %u returned NULL", flinfo->fn_oid);

  return result;
}

Datum
FunctionCall1Coll(FmgrInfo *flinfo, Oid collation, Datum arg1)
{
  LOCAL_FCINFO(fcinfo, 1);
  Datum   result;

  InitFunctionCallInfoData(*fcinfo, flinfo, 1, collation, NULL, NULL);

  fcinfo->args[0].value = arg1;
  fcinfo->args[0].isnull = false;

  result = FunctionCallInvoke(fcinfo);

  /* Check for null result, since caller is clearly not expecting one */
  if (fcinfo->isnull)
    elog(ERROR, "function %u returned NULL", flinfo->fn_oid);

  return result;
}

Datum
FunctionCall2Coll(FmgrInfo *flinfo, Oid collation, Datum arg1, Datum arg2)
{
  LOCAL_FCINFO(fcinfo, 2);
  Datum   result;

  InitFunctionCallInfoData(*fcinfo, flinfo, 2, collation, NULL, NULL);

  fcinfo->args[0].value = arg1;
  fcinfo->args[0].isnull = false;
  fcinfo->args[1].value = arg2;
  fcinfo->args[1].isnull = false;

  result = FunctionCallInvoke(fcinfo);

  /* Check for null result, since caller is clearly not expecting one */
  if (fcinfo->isnull)
    elog(ERROR, "function %u returned NULL", flinfo->fn_oid);

  return result;
}

Datum
FunctionCall3Coll(FmgrInfo *flinfo, Oid collation, Datum arg1, Datum arg2,
          Datum arg3)
{
  LOCAL_FCINFO(fcinfo, 3);
  Datum   result;

  InitFunctionCallInfoData(*fcinfo, flinfo, 3, collation, NULL, NULL);

  fcinfo->args[0].value = arg1;
  fcinfo->args[0].isnull = false;
  fcinfo->args[1].value = arg2;
  fcinfo->args[1].isnull = false;
  fcinfo->args[2].value = arg3;
  fcinfo->args[2].isnull = false;

  result = FunctionCallInvoke(fcinfo);

  /* Check for null result, since caller is clearly not expecting one */
  if (fcinfo->isnull)
    elog(ERROR, "function %u returned NULL", flinfo->fn_oid);

  return result;
}

Datum
FunctionCall4Coll(FmgrInfo *flinfo, Oid collation, Datum arg1, Datum arg2,
          Datum arg3, Datum arg4)
{
  LOCAL_FCINFO(fcinfo, 4);
  Datum   result;

  InitFunctionCallInfoData(*fcinfo, flinfo, 4, collation, NULL, NULL);

  fcinfo->args[0].value = arg1;
  fcinfo->args[0].isnull = false;
  fcinfo->args[1].value = arg2;
  fcinfo->args[1].isnull = false;
  fcinfo->args[2].value = arg3;
  fcinfo->args[2].isnull = false;
  fcinfo->args[3].value = arg4;
  fcinfo->args[3].isnull = false;

  result = FunctionCallInvoke(fcinfo);

  /* Check for null result, since caller is clearly not expecting one */
  if (fcinfo->isnull)
    elog(ERROR, "function %u returned NULL", flinfo->fn_oid);

  return result;
}

Datum
FunctionCall5Coll(FmgrInfo *flinfo, Oid collation, Datum arg1, Datum arg2,
          Datum arg3, Datum arg4, Datum arg5)
{
  LOCAL_FCINFO(fcinfo, 5);
  Datum   result;

  InitFunctionCallInfoData(*fcinfo, flinfo, 5, collation, NULL, NULL);

  fcinfo->args[0].value = arg1;
  fcinfo->args[0].isnull = false;
  fcinfo->args[1].value = arg2;
  fcinfo->args[1].isnull = false;
  fcinfo->args[2].value = arg3;
  fcinfo->args[2].isnull = false;
  fcinfo->args[3].value = arg4;
  fcinfo->args[3].isnull = false;
  fcinfo->args[4].value = arg5;
  fcinfo->args[4].isnull = false;

  result = FunctionCallInvoke(fcinfo);

  /* Check for null result, since caller is clearly not expecting one */
  if (fcinfo->isnull)
    elog(ERROR, "function %u returned NULL", flinfo->fn_oid);

  return result;
}

Datum
FunctionCall6Coll(FmgrInfo *flinfo, Oid collation, Datum arg1, Datum arg2,
          Datum arg3, Datum arg4, Datum arg5,
          Datum arg6)
{
  LOCAL_FCINFO(fcinfo, 6);
  Datum   result;

  InitFunctionCallInfoData(*fcinfo, flinfo, 6, collation, NULL, NULL);

  fcinfo->args[0].value = arg1;
  fcinfo->args[0].isnull = false;
  fcinfo->args[1].value = arg2;
  fcinfo->args[1].isnull = false;
  fcinfo->args[2].value = arg3;
  fcinfo->args[2].isnull = false;
  fcinfo->args[3].value = arg4;
  fcinfo->args[3].isnull = false;
  fcinfo->args[4].value = arg5;
  fcinfo->args[4].isnull = false;
  fcinfo->args[5].value = arg6;
  fcinfo->args[5].isnull = false;

  result = FunctionCallInvoke(fcinfo);

  /* Check for null result, since caller is clearly not expecting one */
  if (fcinfo->isnull)
    elog(ERROR, "function %u returned NULL", flinfo->fn_oid);

  return result;
}

Datum
FunctionCall7Coll(FmgrInfo *flinfo, Oid collation, Datum arg1, Datum arg2,
          Datum arg3, Datum arg4, Datum arg5,
          Datum arg6, Datum arg7)
{
  LOCAL_FCINFO(fcinfo, 7);
  Datum   result;

  InitFunctionCallInfoData(*fcinfo, flinfo, 7, collation, NULL, NULL);

  fcinfo->args[0].value = arg1;
  fcinfo->args[0].isnull = false;
  fcinfo->args[1].value = arg2;
  fcinfo->args[1].isnull = false;
  fcinfo->args[2].value = arg3;
  fcinfo->args[2].isnull = false;
  fcinfo->args[3].value = arg4;
  fcinfo->args[3].isnull = false;
  fcinfo->args[4].value = arg5;
  fcinfo->args[4].isnull = false;
  fcinfo->args[5].value = arg6;
  fcinfo->args[5].isnull = false;
  fcinfo->args[6].value = arg7;
  fcinfo->args[6].isnull = false;

  result = FunctionCallInvoke(fcinfo);

  /* Check for null result, since caller is clearly not expecting one */
  if (fcinfo->isnull)
    elog(ERROR, "function %u returned NULL", flinfo->fn_oid);

  return result;
}

Datum
FunctionCall8Coll(FmgrInfo *flinfo, Oid collation, Datum arg1, Datum arg2,
          Datum arg3, Datum arg4, Datum arg5,
          Datum arg6, Datum arg7, Datum arg8)
{
  LOCAL_FCINFO(fcinfo, 8);
  Datum   result;

  InitFunctionCallInfoData(*fcinfo, flinfo, 8, collation, NULL, NULL);

  fcinfo->args[0].value = arg1;
  fcinfo->args[0].isnull = false;
  fcinfo->args[1].value = arg2;
  fcinfo->args[1].isnull = false;
  fcinfo->args[2].value = arg3;
  fcinfo->args[2].isnull = false;
  fcinfo->args[3].value = arg4;
  fcinfo->args[3].isnull = false;
  fcinfo->args[4].value = arg5;
  fcinfo->args[4].isnull = false;
  fcinfo->args[5].value = arg6;
  fcinfo->args[5].isnull = false;
  fcinfo->args[6].value = arg7;
  fcinfo->args[6].isnull = false;
  fcinfo->args[7].value = arg8;
  fcinfo->args[7].isnull = false;

  result = FunctionCallInvoke(fcinfo);

  /* Check for null result, since caller is clearly not expecting one */
  if (fcinfo->isnull)
    elog(ERROR, "function %u returned NULL", flinfo->fn_oid);

  return result;
}

Datum
FunctionCall9Coll(FmgrInfo *flinfo, Oid collation, Datum arg1, Datum arg2,
          Datum arg3, Datum arg4, Datum arg5,
          Datum arg6, Datum arg7, Datum arg8,
          Datum arg9)
{
  LOCAL_FCINFO(fcinfo, 9);
  Datum   result;

  InitFunctionCallInfoData(*fcinfo, flinfo, 9, collation, NULL, NULL);

  fcinfo->args[0].value = arg1;
  fcinfo->args[0].isnull = false;
  fcinfo->args[1].value = arg2;
  fcinfo->args[1].isnull = false;
  fcinfo->args[2].value = arg3;
  fcinfo->args[2].isnull = false;
  fcinfo->args[3].value = arg4;
  fcinfo->args[3].isnull = false;
  fcinfo->args[4].value = arg5;
  fcinfo->args[4].isnull = false;
  fcinfo->args[5].value = arg6;
  fcinfo->args[5].isnull = false;
  fcinfo->args[6].value = arg7;
  fcinfo->args[6].isnull = false;
  fcinfo->args[7].value = arg8;
  fcinfo->args[7].isnull = false;
  fcinfo->args[8].value = arg9;
  fcinfo->args[8].isnull = false;

  result = FunctionCallInvoke(fcinfo);

  /* Check for null result, since caller is clearly not expecting one */
  if (fcinfo->isnull)
    elog(ERROR, "function %u returned NULL", flinfo->fn_oid);

  return result;
}


/*
 * These are for invocation of a function identified by OID with a
 * directly-computed parameter list.  Note that neither arguments nor result
 * are allowed to be NULL.  These are essentially fmgr_info() followed
 * by FunctionCallN().  If the same function is to be invoked repeatedly,
 * do the fmgr_info() once and then use FunctionCallN().
 */
Datum
OidFunctionCall0Coll(Oid functionId, Oid collation)
{
  FmgrInfo  flinfo;

  fmgr_info(functionId, &flinfo);

  return FunctionCall0Coll(&flinfo, collation);
}

Datum
OidFunctionCall1Coll(Oid functionId, Oid collation, Datum arg1)
{
  FmgrInfo  flinfo;

  fmgr_info(functionId, &flinfo);

  return FunctionCall1Coll(&flinfo, collation, arg1);
}

Datum
OidFunctionCall2Coll(Oid functionId, Oid collation, Datum arg1, Datum arg2)
{
  FmgrInfo  flinfo;

  fmgr_info(functionId, &flinfo);

  return FunctionCall2Coll(&flinfo, collation, arg1, arg2);
}

Datum
OidFunctionCall3Coll(Oid functionId, Oid collation, Datum arg1, Datum arg2,
           Datum arg3)
{
  FmgrInfo  flinfo;

  fmgr_info(functionId, &flinfo);

  return FunctionCall3Coll(&flinfo, collation, arg1, arg2, arg3);
}

Datum
OidFunctionCall4Coll(Oid functionId, Oid collation, Datum arg1, Datum arg2,
           Datum arg3, Datum arg4)
{
  FmgrInfo  flinfo;

  fmgr_info(functionId, &flinfo);

  return FunctionCall4Coll(&flinfo, collation, arg1, arg2, arg3, arg4);
}

Datum
OidFunctionCall5Coll(Oid functionId, Oid collation, Datum arg1, Datum arg2,
           Datum arg3, Datum arg4, Datum arg5)
{
  FmgrInfo  flinfo;

  fmgr_info(functionId, &flinfo);

  return FunctionCall5Coll(&flinfo, collation, arg1, arg2, arg3, arg4, arg5);
}

Datum
OidFunctionCall6Coll(Oid functionId, Oid collation, Datum arg1, Datum arg2,
           Datum arg3, Datum arg4, Datum arg5,
           Datum arg6)
{
  FmgrInfo  flinfo;

  fmgr_info(functionId, &flinfo);

  return FunctionCall6Coll(&flinfo, collation, arg1, arg2, arg3, arg4, arg5,
               arg6);
}

Datum
OidFunctionCall7Coll(Oid functionId, Oid collation, Datum arg1, Datum arg2,
           Datum arg3, Datum arg4, Datum arg5,
           Datum arg6, Datum arg7)
{
  FmgrInfo  flinfo;

  fmgr_info(functionId, &flinfo);

  return FunctionCall7Coll(&flinfo, collation, arg1, arg2, arg3, arg4, arg5,
               arg6, arg7);
}

Datum
OidFunctionCall8Coll(Oid functionId, Oid collation, Datum arg1, Datum arg2,
           Datum arg3, Datum arg4, Datum arg5,
           Datum arg6, Datum arg7, Datum arg8)
{
  FmgrInfo  flinfo;

  fmgr_info(functionId, &flinfo);

  return FunctionCall8Coll(&flinfo, collation, arg1, arg2, arg3, arg4, arg5,
               arg6, arg7, arg8);
}

Datum
OidFunctionCall9Coll(Oid functionId, Oid collation, Datum arg1, Datum arg2,
           Datum arg3, Datum arg4, Datum arg5,
           Datum arg6, Datum arg7, Datum arg8,
           Datum arg9)
{
  FmgrInfo  flinfo;

  fmgr_info(functionId, &flinfo);

  return FunctionCall9Coll(&flinfo, collation, arg1, arg2, arg3, arg4, arg5,
               arg6, arg7, arg8, arg9);
}


/*
 * Special cases for convenient invocation of datatype I/O functions.
 */

/*
 * Call a previously-looked-up datatype input function.
 *
 * "str" may be NULL to indicate we are reading a NULL.  In this case
 * the caller should assume the result is NULL, but we'll call the input
 * function anyway if it's not strict.  So this is almost but not quite
 * the same as FunctionCall3.
 */
Datum
InputFunctionCall(FmgrInfo *flinfo, const char *str, Oid typioparam, int32 typmod)
{
  LOCAL_FCINFO(fcinfo, 3);
  Datum   result;

  if (str == NULL && flinfo->fn_strict)
    return (Datum) 0;   /* just return null result */

  InitFunctionCallInfoData(*fcinfo, flinfo, 3, InvalidOid, NULL, NULL);

  fcinfo->args[0].value = CStringGetDatum(str);
  fcinfo->args[0].isnull = false;
  fcinfo->args[1].value = ObjectIdGetDatum(typioparam);
  fcinfo->args[1].isnull = false;
  fcinfo->args[2].value = Int32GetDatum(typmod);
  fcinfo->args[2].isnull = false;

  result = FunctionCallInvoke(fcinfo);

  /* Should get null result if and only if str is NULL */
  if (str == NULL)
  {
    if (!fcinfo->isnull)
      elog(ERROR, "input function %u returned non-NULL",
         flinfo->fn_oid);
  }
  else
  {
    if (fcinfo->isnull)
      elog(ERROR, "input function %u returned NULL",
         flinfo->fn_oid);
  }

  return result;
}

/*
 * Call a previously-looked-up datatype input function, with non-exception
 * handling of "soft" errors.
 *
 * This is basically like InputFunctionCall, but the converted Datum is
 * returned into *result while the function result is true for success or
 * false for failure.  Also, the caller may pass an ErrorSaveContext node.
 *
 * If escontext points to an ErrorSaveContext, any "soft" errors detected by
 * the input function will be reported by filling the escontext struct and
 * returning false.  (The caller can choose to test SOFT_ERROR_OCCURRED(),
 * but checking the function result instead is usually cheaper.)
 *
 * If escontext does not point to an ErrorSaveContext, errors are reported
 * via ereport(ERROR), so that there is no functional difference from
 * InputFunctionCall; the result will always be true if control returns.
 */
bool
InputFunctionCallSafe(FmgrInfo *flinfo, const char *str,
            Oid typioparam, int32 typmod,
            Node *escontext,
            Datum *result)
{
  LOCAL_FCINFO(fcinfo, 3);

  if (str == NULL && flinfo->fn_strict)
  {
    *result = (Datum) 0;  /* just return null result */
    return true;
  }

  InitFunctionCallInfoData(*fcinfo, flinfo, 3, InvalidOid, escontext, NULL);

  fcinfo->args[0].value = CStringGetDatum(str);
  fcinfo->args[0].isnull = false;
  fcinfo->args[1].value = ObjectIdGetDatum(typioparam);
  fcinfo->args[1].isnull = false;
  fcinfo->args[2].value = Int32GetDatum(typmod);
  fcinfo->args[2].isnull = false;

  *result = FunctionCallInvoke(fcinfo);

  /* Result value is garbage, and could be null, if an error was reported */
  if (SOFT_ERROR_OCCURRED(escontext))
    return false;

  /* Otherwise, should get null result if and only if str is NULL */
  if (str == NULL)
  {
    if (!fcinfo->isnull)
      elog(ERROR, "input function %u returned non-NULL",
         flinfo->fn_oid);
  }
  else
  {
    if (fcinfo->isnull)
      elog(ERROR, "input function %u returned NULL",
         flinfo->fn_oid);
  }

  return true;
}

/*
 * Call a directly-named datatype input function, with non-exception
 * handling of "soft" errors.
 *
 * This is like InputFunctionCallSafe, except that it is given a direct
 * pointer to the C function to call.  We assume that that function is
 * strict.  Also, the function cannot be one that needs to
 * look at FmgrInfo, since there won't be any.
 */
bool
DirectInputFunctionCallSafe(PGFunction func, const char *str,
              Oid typioparam, int32 typmod,
              Node *escontext,
              Datum *result)
{
  LOCAL_FCINFO(fcinfo, 3);

  if (str == NULL)
  {
    *result = (Datum) 0;  /* just return null result */
    return true;
  }

  InitFunctionCallInfoData(*fcinfo, NULL, 3, InvalidOid, escontext, NULL);

  fcinfo->args[0].value = CStringGetDatum(str);
  fcinfo->args[0].isnull = false;
  fcinfo->args[1].value = ObjectIdGetDatum(typioparam);
  fcinfo->args[1].isnull = false;
  fcinfo->args[2].value = Int32GetDatum(typmod);
  fcinfo->args[2].isnull = false;

  *result = (*func) (fcinfo);

  /* Result value is garbage, and could be null, if an error was reported */
  if (SOFT_ERROR_OCCURRED(escontext))
    return false;

  /* Otherwise, shouldn't get null result */
  if (fcinfo->isnull)
    elog(ERROR, "input function %p returned NULL", (void *) func);

  return true;
}

/*
 * Call a previously-looked-up datatype output function.
 *
 * Do not call this on NULL datums.
 *
 * This is currently little more than window dressing for FunctionCall1.
 */
char *
OutputFunctionCall(FmgrInfo *flinfo, Datum val)
{
  return DatumGetCString(FunctionCall1(flinfo, val));
}

/*
 * Call a previously-looked-up datatype binary-input function.
 *
 * "buf" may be NULL to indicate we are reading a NULL.  In this case
 * the caller should assume the result is NULL, but we'll call the receive
 * function anyway if it's not strict.  So this is almost but not quite
 * the same as FunctionCall3.
 */
Datum
ReceiveFunctionCall(FmgrInfo *flinfo, StringInfo buf,
          Oid typioparam, int32 typmod)
{
  LOCAL_FCINFO(fcinfo, 3);
  Datum   result;

  if (buf == NULL && flinfo->fn_strict)
    return (Datum) 0;   /* just return null result */

  InitFunctionCallInfoData(*fcinfo, flinfo, 3, InvalidOid, NULL, NULL);

  fcinfo->args[0].value = PointerGetDatum(buf);
  fcinfo->args[0].isnull = false;
  fcinfo->args[1].value = ObjectIdGetDatum(typioparam);
  fcinfo->args[1].isnull = false;
  fcinfo->args[2].value = Int32GetDatum(typmod);
  fcinfo->args[2].isnull = false;

  result = FunctionCallInvoke(fcinfo);

  /* Should get null result if and only if buf is NULL */
  if (buf == NULL)
  {
    if (!fcinfo->isnull)
      elog(ERROR, "receive function %u returned non-NULL",
         flinfo->fn_oid);
  }
  else
  {
    if (fcinfo->isnull)
      elog(ERROR, "receive function %u returned NULL",
         flinfo->fn_oid);
  }

  return result;
}

/*
 * Call a previously-looked-up datatype binary-output function.
 *
 * Do not call this on NULL datums.
 *
 * This is little more than window dressing for FunctionCall1, but it does
 * guarantee a non-toasted result, which strictly speaking the underlying
 * function doesn't.
 */
bytea *
SendFunctionCall(FmgrInfo *flinfo, Datum val)
{
  return DatumGetByteaP(FunctionCall1(flinfo, val));
}

/*
 * As above, for I/O functions identified by OID.  These are only to be used
 * in seldom-executed code paths.  They are not only slow but leak memory.
 */
Datum
OidInputFunctionCall(Oid functionId, const char *str, Oid typioparam, int32 typmod)
{
  FmgrInfo  flinfo;

  fmgr_info(functionId, &flinfo);
  return InputFunctionCall(&flinfo, str, typioparam, typmod);
}

char *
OidOutputFunctionCall(Oid functionId, Datum val)
{
  FmgrInfo  flinfo;

  fmgr_info(functionId, &flinfo);
  return OutputFunctionCall(&flinfo, val);
}

Datum
OidReceiveFunctionCall(Oid functionId, StringInfo buf,
             Oid typioparam, int32 typmod)
{
  FmgrInfo  flinfo;

  fmgr_info(functionId, &flinfo);
  return ReceiveFunctionCall(&flinfo, buf, typioparam, typmod);
}

bytea *
OidSendFunctionCall(Oid functionId, Datum val)
{
  FmgrInfo  flinfo;

  fmgr_info(functionId, &flinfo);
  return SendFunctionCall(&flinfo, val);
}


/*-------------------------------------------------------------------------
 *    Support routines for toastable datatypes
 *-------------------------------------------------------------------------
 */

varlena *
pg_detoast_datum(varlena *datum)
{
  if (VARATT_IS_EXTENDED(datum))
    return detoast_attr(datum);
  else
    return datum;
}

varlena *
pg_detoast_datum_copy(varlena *datum)
{
  if (VARATT_IS_EXTENDED(datum))
    return detoast_attr(datum);
  else
  {
    /* Make a modifiable copy of the varlena object */
    Size    len = VARSIZE(datum);
    varlena    *result = (varlena *) palloc(len);

    memcpy(result, datum, len);
    return result;
  }
}

varlena *
pg_detoast_datum_slice(varlena *datum, int32 first, int32 count)
{
  /* Only get the specified portion from the toast rel */
  return detoast_attr_slice(datum, first, count);
}

varlena *
pg_detoast_datum_packed(varlena *datum)
{
  if (VARATT_IS_COMPRESSED(datum) || VARATT_IS_EXTERNAL(datum))
    return detoast_attr(datum);
  else
    return datum;
}

/*-------------------------------------------------------------------------
 *    Support routines for extracting info from fn_expr parse tree
 *
 * These are needed by polymorphic functions, which accept multiple possible
 * input types and need help from the parser to know what they've got.
 * Also, some functions might be interested in whether a parameter is constant.
 * Functions taking VARIADIC ANY also need to know about the VARIADIC keyword.
 *-------------------------------------------------------------------------
 */

/*
 * Get the actual type OID of the function return type
 *
 * Returns InvalidOid if information is not available
 */
Oid
get_fn_expr_rettype(FmgrInfo *flinfo)
{
  Node     *expr;

  /*
   * can't return anything useful if we have no FmgrInfo or if its fn_expr
   * node has not been initialized
   */
  if (!flinfo || !flinfo->fn_expr)
    return InvalidOid;

  expr = flinfo->fn_expr;

  return exprType(expr);
}

/*
 * Get the actual type OID of a specific function argument (counting from 0)
 *
 * Returns InvalidOid if information is not available
 */
Oid
get_fn_expr_argtype(FmgrInfo *flinfo, int argnum)
{
  /*
   * can't return anything useful if we have no FmgrInfo or if its fn_expr
   * node has not been initialized
   */
  if (!flinfo || !flinfo->fn_expr)
    return InvalidOid;

  return get_call_expr_argtype(flinfo->fn_expr, argnum);
}

/*
 * Get the actual type OID of a specific function argument (counting from 0),
 * but working from the calling expression tree instead of FmgrInfo
 *
 * Returns InvalidOid if information is not available
 */
Oid
get_call_expr_argtype(Node *expr, int argnum)
{
  List     *args;
  Oid     argtype;

  if (expr == NULL)
    return InvalidOid;

  if (IsA(expr, FuncExpr))
    args = ((FuncExpr *) expr)->args;
  else if (IsA(expr, OpExpr))
    args = ((OpExpr *) expr)->args;
  else if (IsA(expr, DistinctExpr))
    args = ((DistinctExpr *) expr)->args;
  else if (IsA(expr, ScalarArrayOpExpr))
    args = ((ScalarArrayOpExpr *) expr)->args;
  else if (IsA(expr, NullIfExpr))
    args = ((NullIfExpr *) expr)->args;
  else if (IsA(expr, WindowFunc))
    args = ((WindowFunc *) expr)->args;
  else
    return InvalidOid;

  if (argnum < 0 || argnum >= list_length(args))
    return InvalidOid;

  argtype = exprType((Node *) list_nth(args, argnum));

  /*
   * special hack for ScalarArrayOpExpr: what the underlying function will
   * actually get passed is the element type of the array.
   */
  if (IsA(expr, ScalarArrayOpExpr) &&
    argnum == 1)
    argtype = get_base_element_type(argtype);

  return argtype;
}

/*
 * Find out whether a specific function argument is constant for the
 * duration of a query
 *
 * Returns false if information is not available
 */
bool
get_fn_expr_arg_stable(FmgrInfo *flinfo, int argnum)
{
  /*
   * can't return anything useful if we have no FmgrInfo or if its fn_expr
   * node has not been initialized
   */
  if (!flinfo || !flinfo->fn_expr)
    return false;

  return get_call_expr_arg_stable(flinfo->fn_expr, argnum);
}

/*
 * Find out whether a specific function argument is constant for the
 * duration of a query, but working from the calling expression tree
 *
 * Returns false if information is not available
 */
bool
get_call_expr_arg_stable(Node *expr, int argnum)
{
  List     *args;
  Node     *arg;

  if (expr == NULL)
    return false;

  if (IsA(expr, FuncExpr))
    args = ((FuncExpr *) expr)->args;
  else if (IsA(expr, OpExpr))
    args = ((OpExpr *) expr)->args;
  else if (IsA(expr, DistinctExpr))
    args = ((DistinctExpr *) expr)->args;
  else if (IsA(expr, ScalarArrayOpExpr))
    args = ((ScalarArrayOpExpr *) expr)->args;
  else if (IsA(expr, NullIfExpr))
    args = ((NullIfExpr *) expr)->args;
  else if (IsA(expr, WindowFunc))
    args = ((WindowFunc *) expr)->args;
  else
    return false;

  if (argnum < 0 || argnum >= list_length(args))
    return false;

  arg = (Node *) list_nth(args, argnum);

  /*
   * Either a true Const or an external Param will have a value that doesn't
   * change during the execution of the query.  In future we might want to
   * consider other cases too, e.g. now().
   */
  if (IsA(arg, Const))
    return true;
  if (IsA(arg, Param) &&
    ((Param *) arg)->paramkind == PARAM_EXTERN)
    return true;

  return false;
}

/*
 * Get the VARIADIC flag from the function invocation
 *
 * Returns false (the default assumption) if information is not available
 *
 * Note this is generally only of interest to VARIADIC ANY functions
 */
bool
get_fn_expr_variadic(FmgrInfo *flinfo)
{
  Node     *expr;

  /*
   * can't return anything useful if we have no FmgrInfo or if its fn_expr
   * node has not been initialized
   */
  if (!flinfo || !flinfo->fn_expr)
    return false;

  expr = flinfo->fn_expr;

  if (IsA(expr, FuncExpr))
    return ((FuncExpr *) expr)->funcvariadic;
  else
    return false;
}

/*
 * Set options to FmgrInfo of opclass support function.
 *
 * Opclass support functions are called outside of expressions.  Thanks to that
 * we can use fn_expr to store opclass options as bytea constant.
 */
void
set_fn_opclass_options(FmgrInfo *flinfo, bytea *options)
{
  flinfo->fn_expr = (Node *) makeConst(BYTEAOID, -1, InvalidOid, -1,
                     PointerGetDatum(options),
                     options == NULL, false);
}

/*
 * Check if options are defined for opclass support function.
 */
bool
has_fn_opclass_options(FmgrInfo *flinfo)
{
  if (flinfo && flinfo->fn_expr && IsA(flinfo->fn_expr, Const))
  {
    Const    *expr = (Const *) flinfo->fn_expr;

    if (expr->consttype == BYTEAOID)
      return !expr->constisnull;
  }
  return false;
}

/*
 * Get options for opclass support function.
 */
bytea *
get_fn_opclass_options(FmgrInfo *flinfo)
{
  if (flinfo && flinfo->fn_expr && IsA(flinfo->fn_expr, Const))
  {
    Const    *expr = (Const *) flinfo->fn_expr;

    if (expr->consttype == BYTEAOID)
      return expr->constisnull ? NULL : DatumGetByteaP(expr->constvalue);
  }

  ereport(ERROR,
      (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
       errmsg("operator class options info is absent in function call context")));

  return NULL;
}

/*-------------------------------------------------------------------------
 *    Support routines for procedural language implementations
 *-------------------------------------------------------------------------
 */

/*
 * Verify that a validator is actually associated with the language of a
 * particular function and that the user has access to both the language and
 * the function.  All validators should call this before doing anything
 * substantial.  Doing so ensures a user cannot achieve anything with explicit
 * calls to validators that he could not achieve with CREATE FUNCTION or by
 * simply calling an existing function.
 *
 * When this function returns false, callers should skip all validation work
 * and call PG_RETURN_VOID().  This never happens at present; it is reserved
 * for future expansion.
 *
 * In particular, checking that the validator corresponds to the function's
 * language allows untrusted language validators to assume they process only
 * superuser-chosen source code.  (Untrusted language call handlers, by
 * definition, do assume that.)  A user lacking the USAGE language privilege
 * would be unable to reach the validator through CREATE FUNCTION, so we check
 * that to block explicit calls as well.  Checking the EXECUTE privilege on
 * the function is often superfluous, because most users can clone the
 * function to get an executable copy.  It is meaningful against users with no
 * database TEMP right and no permanent schema CREATE right, thereby unable to
 * create any function.  Also, if the function tracks persistent state by
 * function OID or name, validating the original function might permit more
 * mischief than creating and validating a clone thereof.
 */
bool
CheckFunctionValidatorAccess(Oid validatorOid, Oid functionOid)
{
  HeapTuple procTup;
  HeapTuple langTup;
  Form_pg_proc procStruct;
  Form_pg_language langStruct;
  AclResult aclresult;

  /*
   * Get the function's pg_proc entry.  Throw a user-facing error for bad
   * OID, because validators can be called with user-specified OIDs.
   */
  procTup = SearchSysCache1(PROCOID, ObjectIdGetDatum(functionOid));
  if (!HeapTupleIsValid(procTup))
    ereport(ERROR,
        (errcode(ERRCODE_UNDEFINED_FUNCTION),
         errmsg("function with OID %u does not exist", functionOid)));
  procStruct = (Form_pg_proc) GETSTRUCT(procTup);

  /*
   * Fetch pg_language entry to know if this is the correct validation
   * function for that pg_proc entry.
   */
  langTup = SearchSysCache1(LANGOID, ObjectIdGetDatum(procStruct->prolang));
  if (!HeapTupleIsValid(langTup))
    elog(ERROR, "cache lookup failed for language %u", procStruct->prolang);
  langStruct = (Form_pg_language) GETSTRUCT(langTup);

  if (langStruct->lanvalidator != validatorOid)
    ereport(ERROR,
        (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
         errmsg("language validation function %u called for language %u instead of %u",
            validatorOid, procStruct->prolang,
            langStruct->lanvalidator)));

  /* first validate that we have permissions to use the language */
  aclresult = object_aclcheck(LanguageRelationId, procStruct->prolang, GetUserId(),
                ACL_USAGE);
  if (aclresult != ACLCHECK_OK)
    aclcheck_error(aclresult, OBJECT_LANGUAGE,
             NameStr(langStruct->lanname));

  /*
   * Check whether we are allowed to execute the function itself. If we can
   * execute it, there should be no possible side-effect of
   * compiling/validation that execution can't have.
   */
  aclresult = object_aclcheck(ProcedureRelationId, functionOid, GetUserId(), ACL_EXECUTE);
  if (aclresult != ACLCHECK_OK)
    aclcheck_error(aclresult, OBJECT_FUNCTION, NameStr(procStruct->proname));

  ReleaseSysCache(procTup);
  ReleaseSysCache(langTup);

  return true;
}

Coverage Report

Created: 2026-09-28 06:55