From 571addd729a400cece396d79696adcc63387e43b Mon Sep 17 00:00:00 2001
From: Tom Lane
Date: Wed, 29 Jan 2014 20:03:57 -0500
Subject: Fix unsafe references to errno within error messaging logic.

Various places were supposing that errno could be expected to hold still
within an ereport() nest or similar contexts.  This isn't true necessarily,
though in some cases it accidentally failed to fail depending on how the
compiler chanced to order the subexpressions.  This class of thinko
explains recent reports of odd failures on clang-built versions, typically
missing or inappropriate HINT fields in messages.

Problem identified by Christian Kruse, who also submitted the patch this
commit is based on.  (I fixed a few issues in his patch and found a couple
of additional places with the same disease.)

Back-patch as appropriate to all supported branches.
---
 src/common/username.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

(limited to 'src/common/username.c')

diff --git a/src/common/username.c b/src/common/username.c
index c6812ddd9d1..e946972a561 100644
--- a/src/common/username.c
+++ b/src/common/username.c
@@ -34,17 +34,17 @@ get_user_name(char **errstr)
 {
 #ifndef WIN32
 	struct passwd *pw;
-	uid_t user_id = geteuid();
+	uid_t		user_id = geteuid();
 
 	*errstr = NULL;
 
-	errno = 0;	/* clear errno before call */
+	errno = 0;					/* clear errno before call */
 	pw = getpwuid(user_id);
 	if (!pw)
 	{
-		*errstr = psprintf(_("failed to look up effective user id %d: %s"),
-				(int) user_id, errno ? strerror(errno) :
-				_("user does not exist"));
+		*errstr = psprintf(_("failed to look up effective user id %ld: %s"),
+						   (long) user_id,
+						 errno ? strerror(errno) : _("user does not exist"));
 		return NULL;
 	}
 
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