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Avoid holding a directory FD open across assorted SRF calls.

Browse Source 
This extends the fixes made in commit 085b6b667 to other SRFs with the
same bug, namely pg_logdir_ls(), pgrowlocks(), pg_timezone_names(),
pg_ls_dir(), and pg_tablespace_databases().

Also adjust various comments and documentation to warn against
expecting to clean up resources during a ValuePerCall SRF's final
call.

Back-patch to all supported branches, since these functions were
all born broken.

Justin Pryzby, with cosmetic tweaks by me

Discussion: https://postgr.es/m/20200308173103.GC1357@telsasoft.com
This commit is contained in:
Tom Lane
2020-03-16 21:05:29 -04:00
parent c6b75b3f14
commit 5e4a0b7194
10 changed files with 389 additions and 345 deletions
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80
contrib/adminpack/adminpack.c
View File

@ -45,11 +45,6 @@ PG_FUNCTION_INFO_V1(pg_file_rename);
PG_FUNCTION_INFO_V1(pg_file_unlink);
PG_FUNCTION_INFO_V1(pg_logdir_ls);
typedef struct
{
char *location;
DIR *dirdesc;
} directory_fctx;
/*-----------------------
* some helper functions
@ -281,9 +276,14 @@ pg_file_unlink(PG_FUNCTION_ARGS)
Datum
pg_logdir_ls(PG_FUNCTION_ARGS)
{
FuncCallContext *funcctx;
ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
bool randomAccess;
TupleDesc tupdesc;
Tuplestorestate *tupstore;
AttInMetadata *attinmeta;
DIR *dirdesc;
struct dirent *de;
directory_fctx *fctx;
MemoryContext oldcontext;
if (!superuser())
ereport(ERROR,
@ -293,43 +293,39 @@ pg_logdir_ls(PG_FUNCTION_ARGS)
if (strcmp(Log_filename, "postgresql-%Y-%m-%d_%H%M%S.log") != 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
(errmsg("the log_filename parameter must equal 'postgresql-%%Y-%%m-%%d_%%H%%M%%S.log'"))));
errmsg("the log_filename parameter must equal 'postgresql-%%Y-%%m-%%d_%%H%%M%%S.log'")));
if (SRF_IS_FIRSTCALL())
{
MemoryContext oldcontext;
TupleDesc tupdesc;
/* check to see if caller supports us returning a tuplestore */
if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("set-valued function called in context that cannot accept a set")));
if (!(rsinfo->allowedModes & SFRM_Materialize))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("materialize mode required, but it is not allowed in this context")));
funcctx = SRF_FIRSTCALL_INIT();
oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
/* The tupdesc and tuplestore must be created in ecxt_per_query_memory */
oldcontext = MemoryContextSwitchTo(rsinfo->econtext->ecxt_per_query_memory);
fctx = palloc(sizeof(directory_fctx));
tupdesc = CreateTemplateTupleDesc(2, false);
TupleDescInitEntry(tupdesc, (AttrNumber) 1, "starttime",
TIMESTAMPOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 2, "filename",
TEXTOID, -1, 0);
tupdesc = CreateTemplateTupleDesc(2, false);
TupleDescInitEntry(tupdesc, (AttrNumber) 1, "starttime",
TIMESTAMPOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 2, "filename",
TEXTOID, -1, 0);
randomAccess = (rsinfo->allowedModes & SFRM_Materialize_Random) != 0;
tupstore = tuplestore_begin_heap(randomAccess, false, work_mem);
rsinfo->returnMode = SFRM_Materialize;
rsinfo->setResult = tupstore;
rsinfo->setDesc = tupdesc;
funcctx->attinmeta = TupleDescGetAttInMetadata(tupdesc);
MemoryContextSwitchTo(oldcontext);
fctx->location = pstrdup(Log_directory);
fctx->dirdesc = AllocateDir(fctx->location);
attinmeta = TupleDescGetAttInMetadata(tupdesc);
if (!fctx->dirdesc)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not read directory \"%s\": %m",
fctx->location)));
funcctx->user_fctx = fctx;
MemoryContextSwitchTo(oldcontext);
}
funcctx = SRF_PERCALL_SETUP();
fctx = (directory_fctx *) funcctx->user_fctx;
while ((de = ReadDir(fctx->dirdesc, fctx->location)) != NULL)
dirdesc = AllocateDir(Log_directory);
while ((de = ReadDir(dirdesc, Log_directory)) != NULL)
{
char *values[2];
HeapTuple tuple;
@ -366,13 +362,13 @@ pg_logdir_ls(PG_FUNCTION_ARGS)
/* Seems the timestamp is OK; prepare and return tuple */
values[0] = timestampbuf;
values[1] = psprintf("%s/%s", fctx->location, de->d_name);
values[1] = psprintf("%s/%s", Log_directory, de->d_name);
tuple = BuildTupleFromCStrings(funcctx->attinmeta, values);
tuple = BuildTupleFromCStrings(attinmeta, values);
SRF_RETURN_NEXT(funcctx, HeapTupleGetDatum(tuple));
tuplestore_puttuple(tupstore, tuple);
}
FreeDir(fctx->dirdesc);
SRF_RETURN_DONE(funcctx);
FreeDir(dirdesc);
return (Datum) 0;
}

144
contrib/pgrowlocks/pgrowlocks.c
View File

@ -52,13 +52,6 @@ PG_FUNCTION_INFO_V1(pgrowlocks);
#define NCHARS 32
typedef struct
{
Relation rel;
HeapScanDesc scan;
int ncolumns;
} MyData;
#define Atnum_tid 0
#define Atnum_xmax 1
#define Atnum_ismulti 2
@ -69,77 +62,80 @@ typedef struct
Datum
pgrowlocks(PG_FUNCTION_ARGS)
{
FuncCallContext *funcctx;
text *relname = PG_GETARG_TEXT_PP(0);
ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
bool randomAccess;
TupleDesc tupdesc;
Tuplestorestate *tupstore;
AttInMetadata *attinmeta;
Relation rel;
RangeVar *relrv;
HeapScanDesc scan;
HeapTuple tuple;
TupleDesc tupdesc;
AttInMetadata *attinmeta;
Datum result;
MyData *mydata;
Relation rel;
MemoryContext oldcontext;
AclResult aclresult;
char **values;
if (SRF_IS_FIRSTCALL())
{
text *relname;
RangeVar *relrv;
MemoryContext oldcontext;
AclResult aclresult;
/* check to see if caller supports us returning a tuplestore */
if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("set-valued function called in context that cannot accept a set")));
if (!(rsinfo->allowedModes & SFRM_Materialize))
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("materialize mode required, but it is not allowed in this context")));
funcctx = SRF_FIRSTCALL_INIT();
oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
/* The tupdesc and tuplestore must be created in ecxt_per_query_memory */
oldcontext = MemoryContextSwitchTo(rsinfo->econtext->ecxt_per_query_memory);
/* Build a tuple descriptor for our result type */
if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
elog(ERROR, "return type must be a row type");
if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
elog(ERROR, "return type must be a row type");
attinmeta = TupleDescGetAttInMetadata(tupdesc);
funcctx->attinmeta = attinmeta;
randomAccess = (rsinfo->allowedModes & SFRM_Materialize_Random) != 0;
tupstore = tuplestore_begin_heap(randomAccess, false, work_mem);
rsinfo->returnMode = SFRM_Materialize;
rsinfo->setResult = tupstore;
rsinfo->setDesc = tupdesc;
relname = PG_GETARG_TEXT_PP(0);
relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname));
rel = relation_openrv(relrv, AccessShareLock);
MemoryContextSwitchTo(oldcontext);
if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is a partitioned table",
RelationGetRelationName(rel)),
errdetail("Partitioned tables do not contain rows.")));
else if (rel->rd_rel->relkind != RELKIND_RELATION)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not a table",
RelationGetRelationName(rel))));
/* Access the table */
relrv = makeRangeVarFromNameList(textToQualifiedNameList(relname));
rel = relation_openrv(relrv, AccessShareLock);
/*
* check permissions: must have SELECT on table or be in
* pg_stat_scan_tables
*/
aclresult = pg_class_aclcheck(RelationGetRelid(rel), GetUserId(),
ACL_SELECT);
if (aclresult != ACLCHECK_OK)
aclresult = is_member_of_role(GetUserId(), DEFAULT_ROLE_STAT_SCAN_TABLES) ? ACLCHECK_OK : ACLCHECK_NO_PRIV;
if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is a partitioned table",
RelationGetRelationName(rel)),
errdetail("Partitioned tables do not contain rows.")));
else if (rel->rd_rel->relkind != RELKIND_RELATION)
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not a table",
RelationGetRelationName(rel))));
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, ACL_KIND_CLASS,
RelationGetRelationName(rel));
/*
* check permissions: must have SELECT on table or be in
* pg_stat_scan_tables
*/
aclresult = pg_class_aclcheck(RelationGetRelid(rel), GetUserId(),
ACL_SELECT);
if (aclresult != ACLCHECK_OK)
aclresult = is_member_of_role(GetUserId(), DEFAULT_ROLE_STAT_SCAN_TABLES) ? ACLCHECK_OK : ACLCHECK_NO_PRIV;
scan = heap_beginscan(rel, GetActiveSnapshot(), 0, NULL);
mydata = palloc(sizeof(*mydata));
mydata->rel = rel;
mydata->scan = scan;
mydata->ncolumns = tupdesc->natts;
funcctx->user_fctx = mydata;
if (aclresult != ACLCHECK_OK)
aclcheck_error(aclresult, ACL_KIND_CLASS,
RelationGetRelationName(rel));
MemoryContextSwitchTo(oldcontext);
}
/* Scan the relation */
scan = heap_beginscan(rel, GetActiveSnapshot(), 0, NULL);
funcctx = SRF_PERCALL_SETUP();
attinmeta = funcctx->attinmeta;
mydata = (MyData *) funcctx->user_fctx;
scan = mydata->scan;
attinmeta = TupleDescGetAttInMetadata(tupdesc);
values = (char **) palloc(tupdesc->natts * sizeof(char *));
/* scan the relation */
while ((tuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
{
HTSU_Result htsu;
@ -160,10 +156,6 @@ pgrowlocks(PG_FUNCTION_ARGS)
*/
if (htsu == HeapTupleBeingUpdated)
{
char **values;
values = (char **) palloc(mydata->ncolumns * sizeof(char *));
values[Atnum_tid] = (char *) DirectFunctionCall1(tidout,
PointerGetDatum(&tuple->t_self));
@ -288,16 +280,7 @@ pgrowlocks(PG_FUNCTION_ARGS)
/* build a tuple */
tuple = BuildTupleFromCStrings(attinmeta, values);
/* make the tuple into a datum */
result = HeapTupleGetDatum(tuple);
/*
* no need to pfree what we allocated; it's on a short-lived
* memory context anyway
*/
SRF_RETURN_NEXT(funcctx, result);
tuplestore_puttuple(tupstore, tuple);
}
else
{
@ -306,7 +289,6 @@ pgrowlocks(PG_FUNCTION_ARGS)
}
heap_endscan(scan);
heap_close(mydata->rel, AccessShareLock);
SRF_RETURN_DONE(funcctx);
heap_close(rel, AccessShareLock);
return (Datum) 0;
}