From fb30c9c1c5c36989d6b93906986358cb96936d64 Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Sat, 6 Jul 2019 11:25:37 -0400 Subject: [PATCH] In pg_log_generic(), be more paranoid about preserving errno. This code failed to account for the possibility that malloc() would change errno, resulting in wrong output for %m, not to mention the possibility of message truncation. Such a change is obviously expected when malloc fails, but there's reason to fear that on some platforms even a successful malloc call can modify errno. Discussion: https://postgr.es/m/2576.1527382833@sss.pgh.pa.us --- src/common/logging.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/src/common/logging.c b/src/common/logging.c index f247554a32..895da7150e 100644 --- a/src/common/logging.c +++ b/src/common/logging.c @@ -216,6 +216,8 @@ pg_log_generic_v(enum pg_log_level level, const char *pg_restrict fmt, va_list a buf = pg_malloc_extended(required_len, MCXT_ALLOC_NO_OOM); + errno = save_errno; /* malloc might change errno */ + if (!buf) { /* memory trouble, just print what we can and get out of here */ -- 2.40.0