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Avoid holding a directory FD open across assorted SRF calls.

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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 21:05:28 -04:00
parent 113758155c
commit b4570d33aa
10 changed files with 386 additions and 346 deletions
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78
contrib/adminpack/adminpack.c
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@ -56,11 +56,6 @@ static int64 pg_file_write_internal(text *file, text *data, bool replace);
static bool pg_file_rename_internal(text *file1, text *file2, text *file3);
static Datum pg_logdir_ls_internal(FunctionCallInfo fcinfo);
typedef struct
{
char *location;
DIR *dirdesc;
} directory_fctx;
/*-----------------------
* some helper functions
@ -504,50 +499,51 @@ pg_logdir_ls_v1_1(PG_FUNCTION_ARGS)
static Datum
pg_logdir_ls_internal(FunctionCallInfo fcinfo)
{
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 (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'")));
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);
TupleDescInitEntry(tupdesc, (AttrNumber) 1, "starttime",
TIMESTAMPOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 2, "filename",
TEXTOID, -1, 0);
tupdesc = CreateTemplateTupleDesc(2);
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 open 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;
@ -584,13 +580,13 @@ pg_logdir_ls_internal(FunctionCallInfo fcinfo)
/* 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;
}