From 51c34165614bde5d44a356ba5f1f4f79d8893103 Mon Sep 17 00:00:00 2001 From: Andres Freund Date: Fri, 25 Feb 2022 10:40:32 -0800 Subject: [PATCH] pg_waldump: Fix error message for WAL files smaller than XLOG_BLCKSZ. When opening a WAL file smaller than XLOG_BLCKSZ (e.g. 0 bytes long) while determining the wal_segment_size, pg_waldump checked errno, despite errno not being set by the short read. Resulting in a bogus error message. Author: Kyotaro Horiguchi Discussion: https://postgr.es/m/20220214.181847.775024684568733277.horikyota.ntt@gmail.com Backpatch: 11-, the bug was introducedin fc49e24fa --- src/bin/pg_waldump/pg_waldump.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/src/bin/pg_waldump/pg_waldump.c b/src/bin/pg_waldump/pg_waldump.c index 639bfcd7f7d..cd202a50ced 100644 --- a/src/bin/pg_waldump/pg_waldump.c +++ b/src/bin/pg_waldump/pg_waldump.c @@ -210,8 +210,10 @@ search_directory(const char *directory, const char *fname) if (fd >= 0) { PGAlignedXLogBlock buf; + int r; - if (read(fd, buf.data, XLOG_BLCKSZ) == XLOG_BLCKSZ) + r = read(fd, buf.data, XLOG_BLCKSZ); + if (r == XLOG_BLCKSZ) { XLogLongPageHeader longhdr = (XLogLongPageHeader) buf.data; @@ -223,14 +225,12 @@ search_directory(const char *directory, const char *fname) WalSegSz), fname, WalSegSz); } + else if (r < 0) + fatal_error("could not read file \"%s\": %s", + fname, strerror(errno)); else - { - if (errno != 0) - fatal_error("could not read file \"%s\": %s", - fname, strerror(errno)); - else - fatal_error("not enough data in file \"%s\"", fname); - } + fatal_error("not enough data in file \"%s\"", fname); + close(fd); return true; }