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Add missing_ok option to the SQL functions for reading files.

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This makes it possible to use the functions without getting errors, if there
is a chance that the file might be removed or renamed concurrently.
pg_rewind needs to do just that, although this could be useful for other
purposes too. (The changes to pg_rewind to use these functions will come in
a separate commit.)

The read_binary_file() function isn't very well-suited for extensions.c's
purposes anymore, if it ever was. So bite the bullet and make a copy of it
in extension.c, tailored for that use case. This seems better than the
accidental code reuse, even if it's a some more lines of code.

Michael Paquier, with plenty of kibitzing by me.
This commit is contained in:
Heikki Linnakangas 2015-06-28 21:35:46 +03:00
parent cca8ba9529
commit cb2acb1081
6 changed files with 274 additions and 102 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

42
doc/src/sgml/func.sgml
View File

@ -17811,43 +17811,63 @@ postgres=# SELECT * FROM pg_xlogfile_name_offset(pg_stop_backup());
<tbody>
<row>
<entry>
<literal><function>pg_ls_dir(<parameter>dirname</> <type>text</>)</function></literal>
<literal><function>pg_ls_dir(<parameter>dirname</> <type>text</> [, <parameter>missing_ok</> <type>boolean</>, <parameter>include_dot_dirs</> <type>boolean</>])</function></literal>
</entry>
<entry><type>setof text</type></entry>
<entry>List the contents of a directory</entry>
<entry>
List the contents of a directory.
</entry>
</row>
<row>
<entry>
<literal><function>pg_read_file(<parameter>filename</> <type>text</> [, <parameter>offset</> <type>bigint</>, <parameter>length</> <type>bigint</>])</function></literal>
<literal><function>pg_read_file(<parameter>filename</> <type>text</> [, <parameter>offset</> <type>bigint</>, <parameter>length</> <type>bigint</> [, <parameter>missing_ok</> <type>boolean</>] ])</function></literal>
</entry>
<entry><type>text</type></entry>
<entry>Return the contents of a text file</entry>
<entry>
Return the contents of a text file.
</entry>
</row>
<row>
<entry>
<literal><function>pg_read_binary_file(<parameter>filename</> <type>text</> [, <parameter>offset</> <type>bigint</>, <parameter>length</> <type>bigint</>])</function></literal>
<literal><function>pg_read_binary_file(<parameter>filename</> <type>text</> [, <parameter>offset</> <type>bigint</>, <parameter>length</> <type>bigint</> [, <parameter>missing_ok</> <type>boolean</>] ])</function></literal>
</entry>
<entry><type>bytea</type></entry>
<entry>Return the contents of a file</entry>
<entry>
Return the contents of a file.
</entry>
</row>
<row>
<entry>
<literal><function>pg_stat_file(<parameter>filename</> <type>text</>)</function></literal>
<literal><function>pg_stat_file(<parameter>filename</> <type>text</>[, <parameter>missing_ok</> <type>boolean</type>])</function></literal>
</entry>
<entry><type>record</type></entry>
<entry>Return information about a file</entry>
<entry>
Return information about a file.
</entry>
</row>
</tbody>
</tgroup>
</table>
<para>
All of these functions take an optional <parameter>missing_ok</> parameter,
which specifies the behaviour when the file or directory does not exist.
If <literal>true</literal>, the function returns NULL (except
<function>pg_ls_dir</>, which returns an empty result set). If
<literal>false</>, an error is raised. The default is <literal>false</>.
</para>
<indexterm>
<primary>pg_ls_dir</primary>
</indexterm>
<para>
<function>pg_ls_dir</> returns all the names in the specified
directory, except the special entries <quote><literal>.</></> and
<quote><literal>..</></>.
<function>pg_ls_dir</> returns the names of all files (and directories
and other special files) in the specified directory. The <parameter>
include_dot_dirs</> indicates whether <quote>.</> and <quote>..</> are
included in the result set. The default is to exclude them
(<literal>false/>), but including them can be useful when
<parameter>missing_ok</> is <literal>true</literal>, to distinguish an
empty directory from an non-existent directory.
</para>
<indexterm>

69
src/backend/commands/extension.c
View File

@ -25,6 +25,8 @@
#include <dirent.h>
#include <limits.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <unistd.h>
#include "access/htup_details.h"
@ -51,6 +53,7 @@
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "utils/rel.h"
#include "utils/snapmgr.h"
#include "utils/tqual.h"
@ -103,6 +106,7 @@ static void ApplyExtensionUpdates(Oid extensionOid,
ExtensionControlFile *pcontrol,
const char *initialVersion,
List *updateVersions);
static char *read_whole_file(const char *filename, int *length);
/*
@ -635,12 +639,11 @@ read_extension_script_file(const ExtensionControlFile *control,
const char *filename)
{
int src_encoding;
bytea *content;
char *src_str;
char *dest_str;
int len;
content = read_binary_file(filename, 0, -1);
src_str = read_whole_file(filename, &len);
/* use database encoding if not given */
if (control->encoding < 0)
@ -649,21 +652,15 @@ read_extension_script_file(const ExtensionControlFile *control,
src_encoding = control->encoding;
/* make sure that source string is valid in the expected encoding */
len = VARSIZE_ANY_EXHDR(content);
src_str = VARDATA_ANY(content);
pg_verify_mbstr_len(src_encoding, src_str, len, false);
/* convert the encoding to the database encoding */
/*
* Convert the encoding to the database encoding. read_whole_file
* null-terminated the string, so if no conversion happens the string is
* valid as is.
*/
dest_str = pg_any_to_server(src_str, len, src_encoding);
/* if no conversion happened, we have to arrange for null termination */
if (dest_str == src_str)
{
dest_str = (char *) palloc(len + 1);
memcpy(dest_str, src_str, len);
dest_str[len] = '\0';
}
return dest_str;
}
@ -3008,3 +3005,49 @@ ExecAlterExtensionContentsStmt(AlterExtensionContentsStmt *stmt,
return extension;
}
/*
* Read the whole of file into memory.
*
* The file contents are returned as a single palloc'd chunk. For convenience
* of the callers, an extra \0 byte is added to the end.
*/
static char *
read_whole_file(const char *filename, int *length)
{
char *buf;
FILE *file;
size_t bytes_to_read;
struct stat fst;
if (stat(filename, &fst) < 0)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not stat file \"%s\": %m", filename)));
if (fst.st_size > (MaxAllocSize - 1))
ereport(ERROR,
(errcode(ERRCODE_PROGRAM_LIMIT_EXCEEDED),
errmsg("file too large")));
bytes_to_read = (size_t) fst.st_size;
if ((file = AllocateFile(filename, PG_BINARY_R)) == NULL)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not open file \"%s\" for reading: %m",
filename)));
buf = (char *) palloc(bytes_to_read + 1);
*length = fread(buf, 1, bytes_to_read, file);
if (ferror(file))
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not read file \"%s\": %m", filename)));
FreeFile(file);
buf[*length] = '\0';
return buf;
}

241
src/backend/utils/adt/genfile.c
View File

@ -35,6 +35,7 @@ typedef struct
{
char *location;
DIR *dirdesc;
bool include_dot_dirs;
} directory_fctx;
@ -87,8 +88,9 @@ convert_and_check_filename(text *arg)
*
* We read the whole of the file when bytes_to_read is negative.
*/
bytea *
read_binary_file(const char *filename, int64 seek_offset, int64 bytes_to_read)
static bytea *
read_binary_file(const char *filename, int64 seek_offset, int64 bytes_to_read,
bool missing_ok)
{
bytea *buf;
size_t nbytes;
@ -103,9 +105,14 @@ read_binary_file(const char *filename, int64 seek_offset, int64 bytes_to_read)
struct stat fst;
if (stat(filename, &fst) < 0)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not stat file \"%s\": %m", filename)));
{
if (missing_ok && errno == ENOENT)
return NULL;
else
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not stat file \"%s\": %m", filename)));
}
bytes_to_read = fst.st_size - seek_offset;
}
@ -118,10 +125,15 @@ read_binary_file(const char *filename, int64 seek_offset, int64 bytes_to_read)
errmsg("requested length too large")));
if ((file = AllocateFile(filename, PG_BINARY_R)) == NULL)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not open file \"%s\" for reading: %m",
filename)));
{
if (missing_ok && errno == ENOENT)
return NULL;
else
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not open file \"%s\" for reading: %m",
filename)));
}
if (fseeko(file, (off_t) seek_offset,
(seek_offset >= 0) ? SEEK_SET : SEEK_END) != 0)
@ -150,17 +162,23 @@ read_binary_file(const char *filename, int64 seek_offset, int64 bytes_to_read)
* in the database encoding.
*/
static text *
read_text_file(const char *filename, int64 seek_offset, int64 bytes_to_read)
read_text_file(const char *filename, int64 seek_offset, int64 bytes_to_read,
bool missing_ok)
{
bytea *buf;
buf = read_binary_file(filename, seek_offset, bytes_to_read);
buf = read_binary_file(filename, seek_offset, bytes_to_read, missing_ok);
/* Make sure the input is valid */
pg_verifymbstr(VARDATA(buf), VARSIZE(buf) - VARHDRSZ, false);
if (buf != NULL)
{
/* Make sure the input is valid */
pg_verifymbstr(VARDATA(buf), VARSIZE(buf) - VARHDRSZ, false);
/* OK, we can cast it to text safely */
return (text *) buf;
/* OK, we can cast it to text safely */
return (text *) buf;
}
else
return NULL;
}
/*
@ -170,42 +188,38 @@ Datum
pg_read_file(PG_FUNCTION_ARGS)
{
text *filename_t = PG_GETARG_TEXT_P(0);
int64 seek_offset = PG_GETARG_INT64(1);
int64 bytes_to_read = PG_GETARG_INT64(2);
int64 seek_offset = 0;
int64 bytes_to_read = -1;
bool missing_ok = false;
char *filename;
text *result;
if (!superuser())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
(errmsg("must be superuser to read files"))));
filename = convert_and_check_filename(filename_t);
/* handle optional arguments */
if (PG_NARGS() >= 3)
{
seek_offset = PG_GETARG_INT64(1);
bytes_to_read = PG_GETARG_INT64(2);
if (bytes_to_read < 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("requested length cannot be negative")));
PG_RETURN_TEXT_P(read_text_file(filename, seek_offset, bytes_to_read));
}
/*
* Read the whole of a file, returning it as text
*/
Datum
pg_read_file_all(PG_FUNCTION_ARGS)
{
text *filename_t = PG_GETARG_TEXT_P(0);
char *filename;
if (!superuser())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
(errmsg("must be superuser to read files"))));
if (bytes_to_read < 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("requested length cannot be negative")));
}
if (PG_NARGS() >= 4)
missing_ok = PG_GETARG_BOOL(3);
filename = convert_and_check_filename(filename_t);
PG_RETURN_TEXT_P(read_text_file(filename, 0, -1));
result = read_text_file(filename, seek_offset, bytes_to_read, missing_ok);
if (result)
PG_RETURN_TEXT_P(result);
else
PG_RETURN_NULL();
}
/*
@ -215,42 +229,72 @@ Datum
pg_read_binary_file(PG_FUNCTION_ARGS)
{
text *filename_t = PG_GETARG_TEXT_P(0);
int64 seek_offset = PG_GETARG_INT64(1);
int64 bytes_to_read = PG_GETARG_INT64(2);
int64 seek_offset = 0;
int64 bytes_to_read = -1;
bool missing_ok = false;
char *filename;
bytea *result;
if (!superuser())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
(errmsg("must be superuser to read files"))));
/* handle optional arguments */
if (PG_NARGS() >= 3)
{
seek_offset = PG_GETARG_INT64(1);
bytes_to_read = PG_GETARG_INT64(2);
if (bytes_to_read < 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("requested length cannot be negative")));
}
if (PG_NARGS() >= 4)
missing_ok = PG_GETARG_BOOL(3);
filename = convert_and_check_filename(filename_t);
if (bytes_to_read < 0)
ereport(ERROR,
(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
errmsg("requested length cannot be negative")));
PG_RETURN_BYTEA_P(read_binary_file(filename, seek_offset, bytes_to_read));
result = read_binary_file(filename, seek_offset,
bytes_to_read, missing_ok);
if (result)
PG_RETURN_BYTEA_P(result);
else
PG_RETURN_NULL();
}
/*
* Read the whole of a file, returning it as bytea
* Wrapper functions for the 1 and 3 argument variants of pg_read_file()
* and pg_binary_read_file().
*
* These are necessary to pass the sanity check in opr_sanity, which checks
* that all built-in functions that share the implementing C function take
* the same number of arguments.
*/
Datum
pg_read_file_off_len(PG_FUNCTION_ARGS)
{
return pg_read_file(fcinfo);
}
Datum
pg_read_file_all(PG_FUNCTION_ARGS)
{
return pg_read_file(fcinfo);
}
Datum
pg_read_binary_file_off_len(PG_FUNCTION_ARGS)
{
return pg_read_binary_file(fcinfo);
}
Datum
pg_read_binary_file_all(PG_FUNCTION_ARGS)
{
text *filename_t = PG_GETARG_TEXT_P(0);
char *filename;
if (!superuser())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
(errmsg("must be superuser to read files"))));
filename = convert_and_check_filename(filename_t);
PG_RETURN_BYTEA_P(read_binary_file(filename, 0, -1));
return pg_read_binary_file(fcinfo);
}
/*
@ -266,18 +310,28 @@ pg_stat_file(PG_FUNCTION_ARGS)
bool isnull[6];
HeapTuple tuple;
TupleDesc tupdesc;
bool missing_ok = false;
if (!superuser())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
(errmsg("must be superuser to get file information"))));
/* check the optional argument */
if (PG_NARGS() == 2)
missing_ok = PG_GETARG_BOOL(1);
filename = convert_and_check_filename(filename_t);
if (stat(filename, &fst) < 0)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not stat file \"%s\": %m", filename)));
{
if (missing_ok && errno == ENOENT)
PG_RETURN_NULL();
else
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not stat file \"%s\": %m", filename)));
}
/*
* This record type had better match the output parameters declared for me
@ -320,6 +374,18 @@ pg_stat_file(PG_FUNCTION_ARGS)
PG_RETURN_DATUM(HeapTupleGetDatum(tuple));
}
/*
* stat a file (1 argument version)
*
* note: this wrapper is necessary to pass the sanity check in opr_sanity,
* which checks that all built-in functions that share the implementing C
* function take the same number of arguments
*/
Datum
pg_stat_file_1arg(PG_FUNCTION_ARGS)
{
return pg_stat_file(fcinfo);
}
/*
* List a directory (returns the filenames only)
@ -330,6 +396,7 @@ pg_ls_dir(PG_FUNCTION_ARGS)
FuncCallContext *funcctx;
struct dirent *de;
directory_fctx *fctx;
MemoryContext oldcontext;
if (!superuser())
ereport(ERROR,
@ -338,7 +405,17 @@ pg_ls_dir(PG_FUNCTION_ARGS)
if (SRF_IS_FIRSTCALL())
{
MemoryContext oldcontext;
bool missing_ok = false;
bool include_dot_dirs = false;
/* check the optional arguments */
if (PG_NARGS() == 3)
{
if (!PG_ARGISNULL(1))
missing_ok = PG_GETARG_BOOL(1);
if (!PG_ARGISNULL(2))
include_dot_dirs = PG_GETARG_BOOL(2);
}
funcctx = SRF_FIRSTCALL_INIT();
oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
@ -346,14 +423,22 @@ pg_ls_dir(PG_FUNCTION_ARGS)
fctx = palloc(sizeof(directory_fctx));
fctx->location = convert_and_check_filename(PG_GETARG_TEXT_P(0));
fctx->include_dot_dirs = include_dot_dirs;
fctx->dirdesc = AllocateDir(fctx->location);
if (!fctx->dirdesc)
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not open directory \"%s\": %m",
fctx->location)));
{
if (missing_ok && errno == ENOENT)
{
MemoryContextSwitchTo(oldcontext);
SRF_RETURN_DONE(funcctx);
}
else
ereport(ERROR,
(errcode_for_file_access(),
errmsg("could not open directory \"%s\": %m",
fctx->location)));
}
funcctx->user_fctx = fctx;
MemoryContextSwitchTo(oldcontext);
}
@ -363,8 +448,9 @@ pg_ls_dir(PG_FUNCTION_ARGS)
while ((de = ReadDir(fctx->dirdesc, fctx->location)) != NULL)
{
if (strcmp(de->d_name, ".") == 0 ||
strcmp(de->d_name, "..") == 0)
if (!fctx->include_dot_dirs &&
(strcmp(de->d_name, ".") == 0 ||
strcmp(de->d_name, "..") == 0))
continue;
SRF_RETURN_NEXT(funcctx, CStringGetTextDatum(de->d_name));
@ -374,3 +460,16 @@ pg_ls_dir(PG_FUNCTION_ARGS)
SRF_RETURN_DONE(funcctx);
}
/*
* List a directory (1 argument version)
*
* note: this wrapper is necessary to pass the sanity check in opr_sanity,
* which checks that all built-in functions that share the implementing C
* function take the same number of arguments.
*/
Datum
pg_ls_dir_1arg(PG_FUNCTION_ARGS)
{
return pg_ls_dir(fcinfo);
}

2
src/include/catalog/catversion.h
View File

@ -53,6 +53,6 @@
*/
/* yyyymmddN */
#define CATALOG_VERSION_NO 201506111
#define CATALOG_VERSION_NO 201506281
#endif

16
src/include/catalog/pg_proc.h
View File

@ -3181,17 +3181,25 @@ DESCR("reload configuration files");
DATA(insert OID = 2622 ( pg_rotate_logfile PGNSP PGUID 12 1 0 0 0 f f f f t f v 0 0 16 "" _null_ _null_ _null_ _null_ _null_ pg_rotate_logfile _null_ _null_ _null_ ));
DESCR("rotate log file");
DATA(insert OID = 2623 ( pg_stat_file PGNSP PGUID 12 1 0 0 0 f f f f t f v 1 0 2249 "25" "{25,20,1184,1184,1184,1184,16}" "{i,o,o,o,o,o,o}" "{filename,size,access,modification,change,creation,isdir}" _null_ _null_ pg_stat_file _null_ _null_ _null_ ));
DATA(insert OID = 2623 ( pg_stat_file PGNSP PGUID 12 1 0 0 0 f f f f t f v 1 0 2249 "25" "{25,20,1184,1184,1184,1184,16}" "{i,o,o,o,o,o,o}" "{filename,size,access,modification,change,creation,isdir}" _null_ _null_ pg_stat_file_1arg _null_ _null_ _null_ ));
DESCR("get information about file");
DATA(insert OID = 2624 ( pg_read_file PGNSP PGUID 12 1 0 0 0 f f f f t f v 3 0 25 "25 20 20" _null_ _null_ _null_ _null_ _null_ pg_read_file _null_ _null_ _null_ ));
DATA(insert OID = 3307 ( pg_stat_file PGNSP PGUID 12 1 0 0 0 f f f f t f v 2 0 2249 "25 16" "{25,16,20,1184,1184,1184,1184,16}" "{i,i,o,o,o,o,o,o}" "{filename,if_not_exists,size,access,modification,change,creation,isdir}" _null_ _null_ pg_stat_file _null_ _null_ _null_ ));
DESCR("get information about file");
DATA(insert OID = 2624 ( pg_read_file PGNSP PGUID 12 1 0 0 0 f f f f t f v 3 0 25 "25 20 20" _null_ _null_ _null_ _null_ _null_ pg_read_file_off_len _null_ _null_ _null_ ));
DESCR("read text from a file");
DATA(insert OID = 3293 ( pg_read_file PGNSP PGUID 12 1 0 0 0 f f f f t f v 4 0 25 "25 20 20 16" _null_ _null_ _null_ _null_ _null_ pg_read_file _null_ _null_ _null_ ));
DESCR("read text from a file");
DATA(insert OID = 3826 ( pg_read_file PGNSP PGUID 12 1 0 0 0 f f f f t f v 1 0 25 "25" _null_ _null_ _null_ _null_ _null_ pg_read_file_all _null_ _null_ _null_ ));
DESCR("read text from a file");
DATA(insert OID = 3827 ( pg_read_binary_file PGNSP PGUID 12 1 0 0 0 f f f f t f v 3 0 17 "25 20 20" _null_ _null_ _null_ _null_ _null_ pg_read_binary_file _null_ _null_ _null_ ));
DATA(insert OID = 3827 ( pg_read_binary_file PGNSP PGUID 12 1 0 0 0 f f f f t f v 3 0 17 "25 20 20" _null_ _null_ _null_ _null_ _null_ pg_read_binary_file_off_len _null_ _null_ _null_ ));
DESCR("read bytea from a file");
DATA(insert OID = 3295 ( pg_read_binary_file PGNSP PGUID 12 1 0 0 0 f f f f t f v 4 0 17 "25 20 20 16" _null_ _null_ _null_ _null_ _null_ pg_read_binary_file _null_ _null_ _null_ ));
DESCR("read bytea from a file");
DATA(insert OID = 3828 ( pg_read_binary_file PGNSP PGUID 12 1 0 0 0 f f f f t f v 1 0 17 "25" _null_ _null_ _null_ _null_ _null_ pg_read_binary_file_all _null_ _null_ _null_ ));
DESCR("read bytea from a file");
DATA(insert OID = 2625 ( pg_ls_dir PGNSP PGUID 12 1 1000 0 0 f f f f t t v 1 0 25 "25" _null_ _null_ _null_ _null_ _null_ pg_ls_dir _null_ _null_ _null_ ));
DATA(insert OID = 2625 ( pg_ls_dir PGNSP PGUID 12 1 1000 0 0 f f f f t t v 1 0 25 "25" _null_ _null_ _null_ _null_ _null_ pg_ls_dir_1arg _null_ _null_ _null_ ));
DESCR("list all files in a directory");
DATA(insert OID = 3297 ( pg_ls_dir PGNSP PGUID 12 1 1000 0 0 f f f f t t v 3 0 25 "25 16 16" _null_ _null_ _null_ _null_ _null_ pg_ls_dir _null_ _null_ _null_ ));
DESCR("list all files in a directory");
DATA(insert OID = 2626 ( pg_sleep PGNSP PGUID 12 1 0 0 0 f f f f t f v 1 0 2278 "701" _null_ _null_ _null_ _null_ _null_ pg_sleep _null_ _null_ _null_ ));
DESCR("sleep for the specified time in seconds");

6
src/include/utils/builtins.h
View File

@ -469,14 +469,16 @@ extern Datum pg_filenode_relation(PG_FUNCTION_ARGS);
extern Datum pg_relation_filepath(PG_FUNCTION_ARGS);
/* genfile.c */
extern bytea *read_binary_file(const char *filename,
int64 seek_offset, int64 bytes_to_read);
extern Datum pg_stat_file(PG_FUNCTION_ARGS);
extern Datum pg_stat_file_1arg(PG_FUNCTION_ARGS);
extern Datum pg_read_file(PG_FUNCTION_ARGS);
extern Datum pg_read_file_off_len(PG_FUNCTION_ARGS);
extern Datum pg_read_file_all(PG_FUNCTION_ARGS);
extern Datum pg_read_binary_file(PG_FUNCTION_ARGS);
extern Datum pg_read_binary_file_off_len(PG_FUNCTION_ARGS);
extern Datum pg_read_binary_file_all(PG_FUNCTION_ARGS);
extern Datum pg_ls_dir(PG_FUNCTION_ARGS);
extern Datum pg_ls_dir_1arg(PG_FUNCTION_ARGS);
/* misc.c */
extern Datum current_database(PG_FUNCTION_ARGS);