Add pg_ls_tmpdir function

This lists the contents of a temporary directory associated to a given
tablespace, useful to get information about on-disk consumption caused
by temporary files used by a session query.  By default, pg_default is
scanned, and a tablespace can be specified as argument.

This function is intended to be used by monitoring tools, and, unlike
pg_ls_dir(), access to them can be granted to non-superusers so that
those monitoring tools can observe the principle of least privilege.
Access is also given by default to members of pg_monitor.

Author: Nathan Bossart
Reviewed-by: Laurenz Albe
Discussion: https://postgr.es/m/92F458A2-6459-44B8-A7F2-2ADD3225046A@amazon.com
This commit is contained in:
Michael Paquier 2018-10-05 09:21:48 +09:00
parent d73f4c74dd
commit 9cd92d1a33
5 changed files with 97 additions and 8 deletions

View File

@ -20355,6 +20355,20 @@ postgres=# SELECT * FROM pg_walfile_name_offset(pg_stop_backup());
role and may be granted to other non-superuser roles.
</entry>
</row>
<row>
<entry>
<literal><function>pg_ls_tmpdir(<optional><parameter>tablespace</parameter> <type>oid</type></optional>)</function></literal>
</entry>
<entry><type>setof record</type></entry>
<entry>
List the name, size, and last modification time of files in the
temporary directory for <parameter>tablespace</parameter>. If
<parameter>tablespace</parameter> is not provided, the
<literal>pg_default</literal> tablespace is used. Access is granted
to members of the <literal>pg_monitor</literal> role and may be
granted to other non-superuser roles.
</entry>
</row>
<row>
<entry>
<literal><function>pg_read_file(<parameter>filename</parameter> <type>text</type> [, <parameter>offset</parameter> <type>bigint</type>, <parameter>length</parameter> <type>bigint</type> [, <parameter>missing_ok</parameter> <type>boolean</type>] ])</function></literal>
@ -20428,6 +20442,19 @@ postgres=# SELECT * FROM pg_walfile_name_offset(pg_stop_backup());
<command>GRANT</command>.
</para>
<indexterm>
<primary>pg_ls_tmpdir</primary>
</indexterm>
<para>
<function>pg_ls_tmpdir</function> returns the name, size, and last modified
time (mtime) of each file in the temporary file directory for the specified
<parameter>tablespace</parameter>. If <parameter>tablespace</parameter> is
not provided, the <literal>pg_default</literal> tablespace is used. By
default only superusers and members of the <literal>pg_monitor</literal>
role can use this function. Access may be granted to others using
<command>GRANT</command>.
</para>
<indexterm>
<primary>pg_read_file</primary>
</indexterm>

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@ -1150,6 +1150,8 @@ REVOKE EXECUTE ON FUNCTION lo_export(oid, text) FROM public;
REVOKE EXECUTE ON FUNCTION pg_ls_logdir() FROM public;
REVOKE EXECUTE ON FUNCTION pg_ls_waldir() FROM public;
REVOKE EXECUTE ON FUNCTION pg_ls_tmpdir() FROM public;
REVOKE EXECUTE ON FUNCTION pg_ls_tmpdir(oid) FROM public;
REVOKE EXECUTE ON FUNCTION pg_read_file(text) FROM public;
REVOKE EXECUTE ON FUNCTION pg_read_file(text,bigint,bigint) FROM public;
@ -1170,6 +1172,8 @@ REVOKE EXECUTE ON FUNCTION pg_ls_dir(text,boolean,boolean) FROM public;
--
GRANT EXECUTE ON FUNCTION pg_ls_logdir() TO pg_monitor;
GRANT EXECUTE ON FUNCTION pg_ls_waldir() TO pg_monitor;
GRANT EXECUTE ON FUNCTION pg_ls_tmpdir() TO pg_monitor;
GRANT EXECUTE ON FUNCTION pg_ls_tmpdir(oid) TO pg_monitor;
GRANT pg_read_all_settings TO pg_monitor;
GRANT pg_read_all_stats TO pg_monitor;

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@ -23,6 +23,7 @@
#include "access/htup_details.h"
#include "access/xlog_internal.h"
#include "catalog/pg_authid.h"
#include "catalog/pg_tablespace_d.h"
#include "catalog/pg_type.h"
#include "funcapi.h"
#include "mb/pg_wchar.h"
@ -31,6 +32,7 @@
#include "storage/fd.h"
#include "utils/builtins.h"
#include "utils/memutils.h"
#include "utils/syscache.h"
#include "utils/timestamp.h"
typedef struct
@ -520,7 +522,7 @@ pg_ls_dir_1arg(PG_FUNCTION_ARGS)
/* Generic function to return a directory listing of files */
static Datum
pg_ls_dir_files(FunctionCallInfo fcinfo, const char *dir)
pg_ls_dir_files(FunctionCallInfo fcinfo, const char *dir, bool missing_ok)
{
FuncCallContext *funcctx;
struct dirent *de;
@ -549,10 +551,18 @@ pg_ls_dir_files(FunctionCallInfo fcinfo, const char *dir)
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);
@ -601,12 +611,50 @@ pg_ls_dir_files(FunctionCallInfo fcinfo, const char *dir)
Datum
pg_ls_logdir(PG_FUNCTION_ARGS)
{
return pg_ls_dir_files(fcinfo, Log_directory);
return pg_ls_dir_files(fcinfo, Log_directory, false);
}
/* Function to return the list of files in the WAL directory */
Datum
pg_ls_waldir(PG_FUNCTION_ARGS)
{
return pg_ls_dir_files(fcinfo, XLOGDIR);
return pg_ls_dir_files(fcinfo, XLOGDIR, false);
}
/*
* Generic function to return the list of files in pgsql_tmp
*/
static Datum
pg_ls_tmpdir(FunctionCallInfo fcinfo, Oid tblspc)
{
char path[MAXPGPATH];
if (!SearchSysCacheExists1(TABLESPACEOID, ObjectIdGetDatum(tblspc)))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("tablespace with OID %u does not exist",
tblspc)));
TempTablespacePath(path, tblspc);
return pg_ls_dir_files(fcinfo, path, true);
}
/*
* Function to return the list of temporary files in the pg_default tablespace's
* pgsql_tmp directory
*/
Datum
pg_ls_tmpdir_noargs(PG_FUNCTION_ARGS)
{
return pg_ls_tmpdir(fcinfo, DEFAULTTABLESPACE_OID);
}
/*
* Function to return the list of temporary files in the specified tablespace's
* pgsql_tmp directory
*/
Datum
pg_ls_tmpdir_1arg(PG_FUNCTION_ARGS)
{
return pg_ls_tmpdir(fcinfo, PG_GETARG_OID(0));
}

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@ -53,6 +53,6 @@
*/
/* yyyymmddN */
#define CATALOG_VERSION_NO 201809301
#define CATALOG_VERSION_NO 201810051
#endif

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@ -10199,6 +10199,16 @@
provolatile => 'v', prorettype => 'record', proargtypes => '',
proallargtypes => '{text,int8,timestamptz}', proargmodes => '{o,o,o}',
proargnames => '{name,size,modification}', prosrc => 'pg_ls_waldir' },
{ oid => '5029', descr => 'list files in the pgsql_tmp directory',
proname => 'pg_ls_tmpdir', procost => '10', prorows => '20', proretset => 't',
provolatile => 'v', prorettype => 'record', proargtypes => '',
proallargtypes => '{text,int8,timestamptz}', proargmodes => '{o,o,o}',
proargnames => '{name,size,modification}', prosrc => 'pg_ls_tmpdir_noargs' },
{ oid => '5030', descr => 'list files in the pgsql_tmp directory',
proname => 'pg_ls_tmpdir', procost => '10', prorows => '20', proretset => 't',
provolatile => 'v', prorettype => 'record', proargtypes => 'oid',
proallargtypes => '{oid,text,int8,timestamptz}', proargmodes => '{i,o,o,o}',
proargnames => '{tablespace,name,size,modification}', prosrc => 'pg_ls_tmpdir_1arg' },
# hash partitioning constraint function
{ oid => '5028', descr => 'hash partition CHECK constraint',