v1-0001-Add-pg_ls_logicalsnapdir-pg_ls_logicalmapdir-and-.patch

From 428681ee0a66b98136445d607bd51026b8a204b4 Mon Sep 17 00:00:00 2001
From: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Date: Sat, 30 Oct 2021 09:27:36 +0000
Subject: [PATCH v1] Add pg_ls_logicalsnapdir, pg_ls_logicalmapdir and
 pg_ls_replslotdir functions

These functions lists the contents of the respective directories,
and are intended to be used by monitoring tools.  Unlike pg_ls_dir(),
access to it 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.
---
 doc/src/sgml/func.sgml                   | 72 ++++++++++++++++++++++++
 src/backend/catalog/system_functions.sql | 12 ++++
 src/backend/utils/adt/genfile.c          | 34 +++++++++++
 src/include/catalog/catversion.h         |  2 +-
 src/include/catalog/pg_proc.dat          | 15 +++++
 5 files changed, 134 insertions(+), 1 deletion(-)

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 4b49dff2ff..51825edb01 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -27407,6 +27407,78 @@ SELECT convert_from(pg_read_binary_file('file_in_utf8.txt'), 'UTF8');
         can be granted EXECUTE to run the function.
        </para></entry>
       </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <indexterm>
+         <primary>pg_ls_logicalsnapdir</primary>
+        </indexterm>
+        <function>pg_ls_logicalsnapdir</function> ()
+        <returnvalue>setof record</returnvalue>
+        ( <parameter>name</parameter> <type>text</type>,
+        <parameter>size</parameter> <type>bigint</type>,
+        <parameter>modification</parameter> <type>timestamp with time zone</type> )
+       </para>
+       <para>
+        Returns the name, size, and last modification time (mtime) of each
+        ordinary file in the server's pg_logical/snapshots directory.
+        Filenames beginning with a dot, directories, and other special files
+        are excluded.
+       </para>
+       <para>
+        This function is restricted to superusers and members of
+        the <literal>pg_monitor</literal> role by default, but other users can
+        be granted EXECUTE to run the function.
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <indexterm>
+         <primary>pg_ls_logicalmapdir</primary>
+        </indexterm>
+        <function>pg_ls_logicalmapdir</function> ()
+        <returnvalue>setof record</returnvalue>
+        ( <parameter>name</parameter> <type>text</type>,
+        <parameter>size</parameter> <type>bigint</type>,
+        <parameter>modification</parameter> <type>timestamp with time zone</type> )
+       </para>
+       <para>
+        Returns the name, size, and last modification time (mtime) of each
+        ordinary file in the server's pg_logical/mappings directory.
+        Filenames beginning with a dot, directories, and other special files
+        are excluded.
+       </para>
+       <para>
+        This function is restricted to superusers and members of
+        the <literal>pg_monitor</literal> role by default, but other users can
+        be granted EXECUTE to run the function.
+       </para></entry>
+      </row>
+
+      <row>
+       <entry role="func_table_entry"><para role="func_signature">
+        <indexterm>
+         <primary>pg_ls_replslotdir</primary>
+        </indexterm>
+        <function>pg_ls_replslotdir</function> ( <parameter>slot_name</parameter> <type>text</type> )
+        <returnvalue>setof record</returnvalue>
+        ( <parameter>name</parameter> <type>text</type>,
+        <parameter>size</parameter> <type>bigint</type>,
+        <parameter>modification</parameter> <type>timestamp with time zone</type> )
+       </para>
+       <para>
+        Returns the name, size, and last modification time (mtime) of each
+        ordinary file in the server's pg_replslot/<parameter>slot_name</parameter> directory.
+        Filenames beginning with a dot, directories, and other special files
+        are excluded.
+       </para>
+       <para>
+        This function is restricted to superusers and members of
+        the <literal>pg_monitor</literal> role by default, but other users can
+        be granted EXECUTE to run the function.
+       </para></entry>
+      </row>
      </tbody>
     </tgroup>
    </table>
diff --git a/src/backend/catalog/system_functions.sql b/src/backend/catalog/system_functions.sql
index 54c93b16c4..f6789025a5 100644
--- a/src/backend/catalog/system_functions.sql
+++ b/src/backend/catalog/system_functions.sql
@@ -701,6 +701,12 @@ REVOKE EXECUTE ON FUNCTION pg_ls_dir(text,boolean,boolean) FROM public;
 
 REVOKE EXECUTE ON FUNCTION pg_log_backend_memory_contexts(integer) FROM PUBLIC;
 
+REVOKE EXECUTE ON FUNCTION pg_ls_logicalsnapdir() FROM PUBLIC;
+
+REVOKE EXECUTE ON FUNCTION pg_ls_logicalmapdir() FROM PUBLIC;
+
+REVOKE EXECUTE ON FUNCTION pg_ls_replslotdir(text) FROM PUBLIC;
+
 --
 -- We also set up some things as accessible to standard roles.
 --
@@ -715,6 +721,12 @@ GRANT EXECUTE ON FUNCTION pg_ls_tmpdir() TO pg_monitor;
 
 GRANT EXECUTE ON FUNCTION pg_ls_tmpdir(oid) TO pg_monitor;
 
+GRANT EXECUTE ON FUNCTION pg_ls_logicalsnapdir() TO pg_monitor;
+
+GRANT EXECUTE ON FUNCTION pg_ls_logicalmapdir() TO pg_monitor;
+
+GRANT EXECUTE ON FUNCTION pg_ls_replslotdir(text) TO pg_monitor;
+
 GRANT pg_read_all_settings TO pg_monitor;
 
 GRANT pg_read_all_stats TO pg_monitor;
diff --git a/src/backend/utils/adt/genfile.c b/src/backend/utils/adt/genfile.c
index c436d9318b..a83700c576 100644
--- a/src/backend/utils/adt/genfile.c
+++ b/src/backend/utils/adt/genfile.c
@@ -720,3 +720,37 @@ pg_ls_archive_statusdir(PG_FUNCTION_ARGS)
 {
 	return pg_ls_dir_files(fcinfo, XLOGDIR "/archive_status", true);
 }
+
+/*
+ * Function to return the list of files in the pg_logical/snapshots directory.
+ */
+Datum
+pg_ls_logicalsnapdir(PG_FUNCTION_ARGS)
+{
+	return pg_ls_dir_files(fcinfo, "pg_logical/snapshots", false);
+}
+
+/*
+ * Function to return the list of files in the pg_logical/mappings directory.
+ */
+Datum
+pg_ls_logicalmapdir(PG_FUNCTION_ARGS)
+{
+	return pg_ls_dir_files(fcinfo, "pg_logical/mappings", false);
+}
+
+/*
+ * Function to return the list of files in the pg_replslot/<replication_slot>
+ * directory.
+ */
+Datum
+pg_ls_replslotdir(PG_FUNCTION_ARGS)
+{
+	text	   *filename_t = PG_GETARG_TEXT_PP(0);
+	char		path[MAXPGPATH + 11];
+	char	   *filename;
+
+	filename = text_to_cstring(filename_t);
+	snprintf(path, sizeof(path), "%s/%s", "pg_replslot", filename);
+	return pg_ls_dir_files(fcinfo, path, false);
+}
diff --git a/src/include/catalog/catversion.h b/src/include/catalog/catversion.h
index 9faf017457..f1c2c4d1e9 100644
--- a/src/include/catalog/catversion.h
+++ b/src/include/catalog/catversion.h
@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	202110272
+#define CATALOG_VERSION_NO	202110300
 
 #endif
diff --git a/src/include/catalog/pg_proc.dat b/src/include/catalog/pg_proc.dat
index d068d6532e..ca0d6ca1d1 100644
--- a/src/include/catalog/pg_proc.dat
+++ b/src/include/catalog/pg_proc.dat
@@ -11619,6 +11619,21 @@
   proallargtypes => '{oid,text,int8,timestamptz}', proargmodes => '{i,o,o,o}',
   proargnames => '{tablespace,name,size,modification}',
   prosrc => 'pg_ls_tmpdir_1arg' },
+{ oid => '4642', descr => 'list of files in the pg_logical/snapshots directory',
+  proname => 'pg_ls_logicalsnapdir', 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_logicalsnapdir' },
+{ oid => '4643', descr => 'list of files in the pg_logical/mappings directory',
+  proname => 'pg_ls_logicalmapdir', 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_logicalmapdir' },
+{ oid => '4644', descr => 'list of files in the pg_logical/mappings directory',
+  proname => 'pg_ls_replslotdir', procost => '10', prorows => '20', proretset => 't',
+  provolatile => 'v', prorettype => 'record', proargtypes => 'text',
+  proallargtypes => '{text,text,int8,timestamptz}', proargmodes => '{i,o,o,o}',
+  proargnames => '{slot_name,name,size,modification}', prosrc => 'pg_ls_replslotdir' },
 
 # hash partitioning constraint function
 { oid => '5028', descr => 'hash partition CHECK constraint',
-- 
2.25.1