PG-1411 Make pg_resetwal work with TDE

As pg_resetwal removes old WAL segments and creates new one with empty
record we can do that write in unencrypted mode. However that requires
new WAL key creation in case if encryption was enabled before.

Author: artemgavrilov

src/bin/pg_resetwal/.gitignore

@@ -1,2 +1,5 @@
 /pg_resetwal
 /tmp_check/
+
+# Source files copied from src/backend/access/transam/
+/xlogreader.c

src/bin/pg_resetwal/Makefile

@@ -21,8 +21,23 @@ OBJS = \
 	$(WIN32RES) \
 	pg_resetwal.o
 
+ifeq ($(enable_percona_ext),yes)
+override CPPFLAGS := -DFRONTEND $(CPPFLAGS)
+
+OBJS += \
+	$(top_srcdir)/src/fe_utils/simple_list.o \
+	$(top_builddir)/src/libtde/libtdexlog.a \
+	$(top_builddir)/src/libtde/libtde.a \
+	xlogreader.o
+
+override CPPFLAGS := -I$(top_srcdir)/contrib/pg_tde/src/include -I$(top_srcdir)/contrib/pg_tde/src/libkmip/libkmip/include $(CPPFLAGS)
+endif
+
 all: pg_resetwal
 
+xlogreader.c: % : $(top_srcdir)/src/backend/access/transam/%
+	rm -f $@ && $(LN_S) $< .
+
 pg_resetwal: $(OBJS) | submake-libpgport
 	$(CC) $(CFLAGS) $^ $(LDFLAGS) $(LDFLAGS_EX) $(LIBS) -o $@$(X)
 
@@ -36,7 +51,7 @@ uninstall:
 	rm -f '$(DESTDIR)$(bindir)/pg_resetwal$(X)'
 
 clean distclean:
-	rm -f pg_resetwal$(X) $(OBJS)
+	rm -f pg_resetwal$(X) $(OBJS) xlogreader.c
 	rm -rf tmp_check
 
 check:

src/bin/pg_resetwal/meson.build

@@ -10,10 +10,22 @@ if host_system == 'windows'
     '--FILEDESC', 'pg_resetwal - reset PostgreSQL WAL log'])
 endif
 
+link_w  = []
+include_dirs = [postgres_inc]
+
+if percona_ext == true
+  link_w = [pg_tde_frontend]
+  include_dirs = [postgres_inc, pg_tde_inc]
+  pg_resetwal_sources += xlogreader_sources
+endif
+
 pg_resetwal = executable('pg_resetwal',
   pg_resetwal_sources,
   dependencies: [frontend_code],
+  c_args: ['-DFRONTEND'], # needed for xlogreader et al
   kwargs: default_bin_args,
+  include_directories: include_dirs,
+  link_with: link_w
 )
 bin_targets += pg_resetwal
 

src/bin/pg_resetwal/pg_resetwal.c

@@ -59,6 +59,13 @@
 #include "pg_getopt.h"
 #include "storage/large_object.h"
 
+#ifdef PERCONA_EXT
+#include "pg_tde.h"
+#include "access/pg_tde_fe_init.h"
+#include "access/pg_tde_xlog_smgr.h"
+#include "access/xlog_smgr.h"
+#endif
+
 static ControlFileData ControlFile; /* pg_control values */
 static XLogSegNo newXlogSegNo;	/* new XLOG segment # */
 static bool guessed = false;	/* T if we had to guess at any values */
@@ -344,6 +351,15 @@ main(int argc, char *argv[])
 	}
 #endif
 
+#ifdef PERCONA_EXT
+	{
+		char tde_path[MAXPGPATH];
+		snprintf(tde_path, sizeof(tde_path), "%s/%s", DataDir, PG_TDE_DATA_DIR);
+		pg_tde_fe_init(tde_path);
+		TDEXLogSmgrInit();
+	}
+#endif
+
 	get_restricted_token();
 
 	/* Set mask based on PGDATA permissions */
@@ -488,6 +504,18 @@ main(int argc, char *argv[])
 		exit(1);
 	}
 
+#ifdef PERCONA_EXT
+	/*
+	 * The only thing that WAL will contain after reset is a checkpoint, so we can
+	 * write it in unencrypted form. There are no sensitive data in it.
+	 *
+	 * We invoke this function here because we want to be sure that everything
+	 * is checked and ready for writing as this function will create new WAL key
+	 * if WAL encryption is enabled.
+	 */
+	TDEXLogSmgrInitWrite(false);
+#endif
+
 	/*
 	 * Else, do the dirty deed.
 	 */
@@ -1134,14 +1162,25 @@ WriteEmptyXLOG(void)
 		pg_fatal("could not open file \"%s\": %m", path);
 
 	errno = 0;
+#ifdef PERCONA_EXT
+	if (xlog_smgr->seg_write(fd, buffer.data, XLOG_BLCKSZ, 0,
+						 ControlFile.checkPointCopy.ThisTimeLineID,
+						 newXlogSegNo, WalSegSz) != XLOG_BLCKSZ)
+#else
 	if (write(fd, buffer.data, XLOG_BLCKSZ) != XLOG_BLCKSZ)
+#endif
 	{
 		/* if write didn't set errno, assume problem is no disk space */
 		if (errno == 0)
 			errno = ENOSPC;
 		pg_fatal("could not write file \"%s\": %m", path);
 	}
 
+#ifdef PERCONA_EXT
+	/* If we used xlog smgr, we need to update the file offset */
+	lseek(fd, XLOG_BLCKSZ, SEEK_CUR);
+#endif
+
 	/* Fill the rest of the file with zeroes */
 	memset(buffer.data, 0, XLOG_BLCKSZ);
 	for (nbytes = XLOG_BLCKSZ; nbytes < WalSegSz; nbytes += XLOG_BLCKSZ)