988a87a03a
vacuum/analyze timestamp columns at the end, rather than at a random spot in the middle as in the original patch. This was deemed more usable as well as less likely to break existing application code. initdb forced accordingly. In passing, remove former kluge for initializing pg_stat_file()'s pg_proc entry --- bootstrap mode was fixed recently so that this can be done without any hacks, but I overlooked this usage.
274 lines
6.9 KiB
C
274 lines
6.9 KiB
C
/*-------------------------------------------------------------------------
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*
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* genfile.c
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* Functions for direct access to files
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*
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*
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* Copyright (c) 2004-2006, PostgreSQL Global Development Group
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*
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* Author: Andreas Pflug <pgadmin@pse-consulting.de>
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/backend/utils/adt/genfile.c,v 1.13 2006/11/24 21:18:42 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include <sys/file.h>
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#include <sys/stat.h>
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#include <unistd.h>
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#include <dirent.h>
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#include "access/heapam.h"
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#include "catalog/pg_type.h"
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#include "funcapi.h"
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#include "miscadmin.h"
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#include "postmaster/syslogger.h"
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#include "storage/fd.h"
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#include "utils/builtins.h"
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#include "utils/memutils.h"
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#include "utils/timestamp.h"
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typedef struct
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{
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char *location;
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DIR *dirdesc;
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} directory_fctx;
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/*
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* Convert a "text" filename argument to C string, and check it's allowable.
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*
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* Filename may be absolute or relative to the DataDir, but we only allow
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* absolute paths that match DataDir or Log_directory.
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*/
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static char *
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convert_and_check_filename(text *arg)
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{
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int input_len = VARSIZE(arg) - VARHDRSZ;
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char *filename = palloc(input_len + 1);
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memcpy(filename, VARDATA(arg), input_len);
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filename[input_len] = '\0';
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canonicalize_path(filename); /* filename can change length here */
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/* Disallow ".." in the path */
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if (path_contains_parent_reference(filename))
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ereport(ERROR,
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(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
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(errmsg("reference to parent directory (\"..\") not allowed"))));
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if (is_absolute_path(filename))
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{
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/* Allow absolute references within DataDir */
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if (path_is_prefix_of_path(DataDir, filename))
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return filename;
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/* The log directory might be outside our datadir, but allow it */
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if (is_absolute_path(Log_directory) &&
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path_is_prefix_of_path(Log_directory, filename))
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return filename;
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ereport(ERROR,
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(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
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(errmsg("absolute path not allowed"))));
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return NULL; /* keep compiler quiet */
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}
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else
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{
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return filename;
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}
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}
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/*
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* Read a section of a file, returning it as text
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*/
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Datum
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pg_read_file(PG_FUNCTION_ARGS)
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{
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text *filename_t = PG_GETARG_TEXT_P(0);
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int64 seek_offset = PG_GETARG_INT64(1);
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int64 bytes_to_read = PG_GETARG_INT64(2);
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char *buf;
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size_t nbytes;
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FILE *file;
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char *filename;
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if (!superuser())
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ereport(ERROR,
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(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
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(errmsg("must be superuser to read files"))));
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filename = convert_and_check_filename(filename_t);
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if ((file = AllocateFile(filename, PG_BINARY_R)) == NULL)
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ereport(ERROR,
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(errcode_for_file_access(),
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errmsg("could not open file \"%s\" for reading: %m",
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filename)));
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if (fseeko(file, (off_t) seek_offset,
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(seek_offset >= 0) ? SEEK_SET : SEEK_END) != 0)
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ereport(ERROR,
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(errcode_for_file_access(),
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errmsg("could not seek in file \"%s\": %m", filename)));
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if (bytes_to_read < 0)
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ereport(ERROR,
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(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
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errmsg("requested length may not be negative")));
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/* not sure why anyone thought that int64 length was a good idea */
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if (bytes_to_read > (MaxAllocSize - VARHDRSZ))
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ereport(ERROR,
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(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
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errmsg("requested length too large")));
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buf = palloc((Size) bytes_to_read + VARHDRSZ);
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nbytes = fread(VARDATA(buf), 1, (size_t) bytes_to_read, file);
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if (ferror(file))
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ereport(ERROR,
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(errcode_for_file_access(),
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errmsg("could not read file \"%s\": %m", filename)));
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VARATT_SIZEP(buf) = nbytes + VARHDRSZ;
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FreeFile(file);
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pfree(filename);
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PG_RETURN_TEXT_P(buf);
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}
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/*
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* stat a file
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*/
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Datum
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pg_stat_file(PG_FUNCTION_ARGS)
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{
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text *filename_t = PG_GETARG_TEXT_P(0);
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char *filename;
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struct stat fst;
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Datum values[6];
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bool isnull[6];
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HeapTuple tuple;
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TupleDesc tupdesc;
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if (!superuser())
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ereport(ERROR,
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(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
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(errmsg("must be superuser to get file information"))));
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filename = convert_and_check_filename(filename_t);
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if (stat(filename, &fst) < 0)
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ereport(ERROR,
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(errcode_for_file_access(),
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errmsg("could not stat file \"%s\": %m", filename)));
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/*
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* This record type had better match the output parameters declared for me
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* in pg_proc.h.
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*/
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tupdesc = CreateTemplateTupleDesc(6, false);
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TupleDescInitEntry(tupdesc, (AttrNumber) 1,
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"size", INT8OID, -1, 0);
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TupleDescInitEntry(tupdesc, (AttrNumber) 2,
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"access", TIMESTAMPTZOID, -1, 0);
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TupleDescInitEntry(tupdesc, (AttrNumber) 3,
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"modification", TIMESTAMPTZOID, -1, 0);
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TupleDescInitEntry(tupdesc, (AttrNumber) 4,
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"change", TIMESTAMPTZOID, -1, 0);
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TupleDescInitEntry(tupdesc, (AttrNumber) 5,
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"creation", TIMESTAMPTZOID, -1, 0);
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TupleDescInitEntry(tupdesc, (AttrNumber) 6,
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"isdir", BOOLOID, -1, 0);
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BlessTupleDesc(tupdesc);
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memset(isnull, false, sizeof(isnull));
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values[0] = Int64GetDatum((int64) fst.st_size);
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values[1] = TimestampTzGetDatum(time_t_to_timestamptz(fst.st_atime));
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values[2] = TimestampTzGetDatum(time_t_to_timestamptz(fst.st_mtime));
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/* Unix has file status change time, while Win32 has creation time */
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#if !defined(WIN32) && !defined(__CYGWIN__)
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values[3] = TimestampTzGetDatum(time_t_to_timestamptz(fst.st_ctime));
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isnull[4] = true;
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#else
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isnull[3] = true;
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values[4] = TimestampTzGetDatum(time_t_to_timestamptz(fst.st_ctime));
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#endif
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values[5] = BoolGetDatum(fst.st_mode & S_IFDIR);
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tuple = heap_form_tuple(tupdesc, values, isnull);
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pfree(filename);
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PG_RETURN_DATUM(HeapTupleGetDatum(tuple));
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}
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/*
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* List a directory (returns the filenames only)
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*/
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Datum
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pg_ls_dir(PG_FUNCTION_ARGS)
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{
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FuncCallContext *funcctx;
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struct dirent *de;
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directory_fctx *fctx;
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if (!superuser())
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ereport(ERROR,
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(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
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(errmsg("must be superuser to get directory listings"))));
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if (SRF_IS_FIRSTCALL())
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{
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MemoryContext oldcontext;
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funcctx = SRF_FIRSTCALL_INIT();
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oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
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fctx = palloc(sizeof(directory_fctx));
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fctx->location = convert_and_check_filename(PG_GETARG_TEXT_P(0));
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fctx->dirdesc = AllocateDir(fctx->location);
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if (!fctx->dirdesc)
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ereport(ERROR,
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(errcode_for_file_access(),
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errmsg("could not open directory \"%s\": %m",
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fctx->location)));
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funcctx->user_fctx = fctx;
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MemoryContextSwitchTo(oldcontext);
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}
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funcctx = SRF_PERCALL_SETUP();
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fctx = (directory_fctx *) funcctx->user_fctx;
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while ((de = ReadDir(fctx->dirdesc, fctx->location)) != NULL)
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{
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int len = strlen(de->d_name);
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text *result;
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if (strcmp(de->d_name, ".") == 0 ||
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strcmp(de->d_name, "..") == 0)
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continue;
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result = palloc(len + VARHDRSZ);
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VARATT_SIZEP(result) = len + VARHDRSZ;
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memcpy(VARDATA(result), de->d_name, len);
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SRF_RETURN_NEXT(funcctx, PointerGetDatum(result));
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}
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FreeDir(fctx->dirdesc);
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SRF_RETURN_DONE(funcctx);
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}
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