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
This commit is contained in:
Tom Lane 2019-07-06 11:25:37 -04:00
parent b33283c364
commit fb30c9c1c5
1 changed files with 2 additions and 0 deletions

View File

@ -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 */