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Add files to do read I/O on the cluster directory:
pg_stat_file() pg_read_file() pg_ls_dir() pg_reload_conf() pg_rotate_logfile() Dave Page Andreas Pflug
This commit is contained in:
Bruce Momjian
258
src/backend/utils/adt/genfile.c
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258
src/backend/utils/adt/genfile.c
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/*-------------------------------------------------------------------------
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*
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* genfile.c
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*
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*
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* Copyright (c) 2004, 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 1.1 2005/08/12 03:24:08 momjian 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 "utils/builtins.h"
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#include "miscadmin.h"
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#include "storage/fd.h"
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#include "catalog/pg_type.h"
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#include "funcapi.h"
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extern char *Log_directory;
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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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* Return an absolute path. Argument may be absolute or
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* relative to the DataDir.
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*/
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static char *check_and_make_absolute(text *arg)
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{
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int datadir_len = strlen(DataDir);
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int filename_len = VARSIZE(arg) - VARHDRSZ;
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char *filename = palloc(filename_len + 1);
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memcpy(filename, VARDATA(arg), filename_len);
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filename[filename_len] = '\0';
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canonicalize_path(filename);
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filename_len = strlen(filename); /* recompute */
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/*
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* Prevent reference to the parent directory.
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* "..a.." is a valid file name though.
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*/
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if (strcmp(filename, "..") == 0 || /* beginning */
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strncmp(filename, "../", 3) == 0 || /* beginning */
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strcmp(filename, "/..") == 0 || /* beginning */
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strncmp(filename, "../", 3) == 0 || /* beginning */
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strstr(filename, "/../") != NULL || /* middle */
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strncmp(filename + filename_len - 3, "/..", 3) == 0) /* end */
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ereport(ERROR,
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(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
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(errmsg("Reference to a parent directory (\"..\") not allowed"))));
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if (is_absolute_path(filename))
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{
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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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strncmp(filename, Log_directory, strlen(Log_directory)) == 0 &&
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(filename[strlen(Log_directory)] == '/' ||
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filename[strlen(Log_directory)] == '\0'))
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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 paths not allowed"))));
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return NULL;
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}
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else
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{
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char *absname = palloc(datadir_len + filename_len + 2);
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sprintf(absname, "%s/%s", DataDir, filename);
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pfree(filename);
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return absname;
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}
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}
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Datum pg_read_file(PG_FUNCTION_ARGS)
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{
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int64 bytes_to_read = PG_GETARG_INT64(2);
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int64 seek_offset = PG_GETARG_INT64(1);
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char *buf = 0;
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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 = check_and_make_absolute(PG_GETARG_TEXT_P(0));
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if ((file = AllocateFile(filename, PG_BINARY_R)) == NULL)
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{
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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", filename)));
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PG_RETURN_NULL();
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}
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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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{
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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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PG_RETURN_NULL();
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}
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if (bytes_to_read < 0)
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{
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ereport(ERROR,
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(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
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errmsg("length cannot be negative")));
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}
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buf = palloc(bytes_to_read + VARHDRSZ);
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nbytes = fread(VARDATA(buf), 1, bytes_to_read, file);
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if (nbytes < 0)
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{
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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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PG_RETURN_NULL();
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}
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VARATT_SIZEP(buf) = nbytes + VARHDRSZ;
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pfree(filename);
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FreeFile(file);
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PG_RETURN_TEXT_P(buf);
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}
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Datum pg_stat_file(PG_FUNCTION_ARGS)
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{
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AttInMetadata *attinmeta;
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char *filename = check_and_make_absolute(PG_GETARG_TEXT_P(0));
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struct stat fst;
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char lenbuf[30], cbuf[30], abuf[30], mbuf[30], dirbuf[2];
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char *values[5] = {lenbuf, cbuf, abuf, mbuf, dirbuf};
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pg_time_t timestamp;
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HeapTuple tuple;
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TupleDesc tupdesc = CreateTemplateTupleDesc(5, false);
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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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TupleDescInitEntry(tupdesc, (AttrNumber) 1, "length", INT8OID, -1, 0);
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TupleDescInitEntry(tupdesc, (AttrNumber) 2, "atime", TIMESTAMPOID, -1, 0);
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TupleDescInitEntry(tupdesc, (AttrNumber) 3, "mtime", TIMESTAMPOID, -1, 0);
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TupleDescInitEntry(tupdesc, (AttrNumber) 4, "ctime", TIMESTAMPOID, -1, 0);
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TupleDescInitEntry(tupdesc, (AttrNumber) 5, "isdir", BOOLOID, -1, 0);
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attinmeta = TupleDescGetAttInMetadata(tupdesc);
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if (stat(filename, &fst) < 0)
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{
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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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PG_RETURN_NULL();
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}
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else
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{
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snprintf(lenbuf, 30, INT64_FORMAT, (int64)fst.st_size);
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timestamp = fst.st_atime;
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pg_strftime(abuf, 30, "%F %T", pg_localtime(×tamp, global_timezone));
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timestamp = fst.st_mtime;
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pg_strftime(mbuf, 30, "%F %T", pg_localtime(×tamp, global_timezone));
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timestamp = fst.st_ctime;
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pg_strftime(cbuf, 30, "%F %T", pg_localtime(×tamp, global_timezone));
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if (fst.st_mode & S_IFDIR)
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strcpy(dirbuf, "t");
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else
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strcpy(dirbuf, "f");
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tuple = BuildTupleFromCStrings(attinmeta, values);
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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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Datum 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 = check_and_make_absolute(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("%s is not browsable: %m", 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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if (!fctx->dirdesc) /* not a readable directory */
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SRF_RETURN_DONE(funcctx);
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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 = palloc(len + VARHDRSZ);
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if (strcmp(de->d_name, ".") == 0 || strcmp(de->d_name, "..") == 0)
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continue;
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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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