From 807cc27ebe4f3cbb260aec85691b8710c844651f Mon Sep 17 00:00:00 2001
From: Grigory Smolkin <g.smolkin@postgrespro.ru>
Date: Wed, 27 Jan 2021 00:23:59 +0300
Subject: [PATCH] Fix overwriting of 0-sized postgresql.auto.conf in remote
 mode, restore nonedata files asynchronously

---
 src/data.c    |  2 +-
 src/restore.c | 22 ++++++++++++++--------
 2 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/src/data.c b/src/data.c
index a3baa3d3..d3f67f43 100644
--- a/src/data.c
+++ b/src/data.c
@@ -1145,7 +1145,7 @@ restore_non_data_file_internal(FILE *in, FILE *out, pgFile *file,
 
 		if (read_len > 0)
 		{
-			if (fio_fwrite(out, buf, read_len) != read_len)
+			if (fio_fwrite_async(out, buf, read_len) != read_len)
 				elog(ERROR, "Cannot write to \"%s\": %s", to_fullpath,
 					 strerror(errno));
 		}
diff --git a/src/restore.c b/src/restore.c
index aa9bff9e..a1f009b0 100644
--- a/src/restore.c
+++ b/src/restore.c
@@ -1515,8 +1515,8 @@ update_recovery_options(pgBackup *backup,
 	char		postgres_auto_path[MAXPGPATH];
 	char		postgres_auto_path_tmp[MAXPGPATH];
 	char		path[MAXPGPATH];
-	FILE	   *fp;
-	FILE	   *fp_tmp;
+	FILE	   *fp = NULL;
+	FILE	   *fp_tmp = NULL;
 	struct stat st;
 	char		current_time_str[100];
 	/* postgresql.auto.conf parsing */
@@ -1540,9 +1540,13 @@ update_recovery_options(pgBackup *backup,
 				 strerror(errno));
 	}
 
-	fp = fio_open_stream(postgres_auto_path, FIO_DB_HOST);
-	if (fp == NULL && errno != ENOENT)
-		elog(ERROR, "cannot open \"%s\": %s", postgres_auto_path, strerror(errno));
+	/* Kludge for 0-sized postgresql.auto.conf file. TODO: make something more intelligent */
+	if (st.st_size > 0)
+	{
+		fp = fio_open_stream(postgres_auto_path, FIO_DB_HOST);
+		if (fp == NULL && errno != ENOENT)
+			elog(ERROR, "cannot open \"%s\": %s", postgres_auto_path, strerror(errno));
+	}
 
 	sprintf(postgres_auto_path_tmp, "%s.tmp", postgres_auto_path);
 	fp_tmp = fio_fopen(postgres_auto_path_tmp, "w", FIO_DB_HOST);
@@ -1582,9 +1586,11 @@ update_recovery_options(pgBackup *backup,
 	if (fp)
 		fio_close_stream(fp);
 
-	/* TODO: detect remote error */
-	if (buf_len > 0)
-		fio_fwrite(fp_tmp, buf, buf_len);
+	/* Write data to postgresql.auto.conf.tmp */
+	if (buf_len > 0 &&
+		(fio_fwrite(fp_tmp, buf, buf_len) != buf_len))
+			elog(ERROR, "Cannot write to \"%s\": %s",
+					postgres_auto_path_tmp, strerror(errno));
 
 	if (fio_fflush(fp_tmp) != 0 ||
 		fio_fclose(fp_tmp))