From 70ed51ccc2e8e6c4976d422af960e4232210fb99 Mon Sep 17 00:00:00 2001
From: Karel Zak <kzak@redhat.com>
Date: Mon, 16 Oct 2017 13:31:47 +0200
Subject: [PATCH 134/135] logger: do not rely only getlogin(3) telling who ran
 the command

The getlogin(3) is known not to always work, and when that happens it
is reasonable to try determine user of name by looking process owner
and passwd information.

Upstream: http://github.com/karelzak/util-linux/commit/019b97024fde3f07eaf541eef990762483369a11
Addresses: https://bugzilla.redhat.com/show_bug.cgi?id=1336432
Signed-off-by: Karel Zak <kzak@redhat.com>
---
 misc-utils/logger.c | 25 ++++++++++++++++---------
 1 file changed, 16 insertions(+), 9 deletions(-)

diff --git a/misc-utils/logger.c b/misc-utils/logger.c
index dfda01866..c1cec45e8 100644
--- a/misc-utils/logger.c
+++ b/misc-utils/logger.c
@@ -49,6 +49,8 @@
 #include <arpa/inet.h>
 #include <netdb.h>
 #include <getopt.h>
+#include <sys/types.h>
+#include <pwd.h>
 
 #include "c.h"
 #include "closestream.h"
@@ -183,9 +185,20 @@ inet_socket(const char *servername, const char *port, const int socket_type)
 	return fd;
 }
 
+static char const *xgetlogin(void)
+{
+	char const *cp;
+	struct passwd *pw;
+
+	if (!(cp = getlogin()) || !*cp)
+		cp = (pw = getpwuid(geteuid()))? pw->pw_name : "<someone>";
+	return cp;
+}
+
 static void
 mysyslog(int fd, int logflags, int pri, char *tag, char *msg) {
-       char *buf, pid[30], *cp, *tp;
+       char *buf, pid[30], *tp;
+       const char *cp;
        time_t now;
 
        if (fd > -1) {
@@ -193,13 +206,7 @@ mysyslog(int fd, int logflags, int pri, char *tag, char *msg) {
                        snprintf (pid, sizeof(pid), "[%d]", getpid());
 	       else
 		       pid[0] = 0;
-               if (tag)
-		       cp = tag;
-	       else {
-		       cp = getlogin();
-		       if (!cp)
-			       cp = "<someone>";
-	       }
+	       cp = tag ? tag : xgetlogin();
                (void)time(&now);
 	       tp = ctime(&now)+4;
 
@@ -334,7 +341,7 @@ main(int argc, char **argv) {
 	else if (usock)
 		LogSock = unix_socket(usock, socket_type);
 	else
-		openlog(tag ? tag : getlogin(), logflags, 0);
+		openlog(tag ? tag : xgetlogin(), logflags, 0);
 
 	buf = xcalloc(1, max_message_size);
 
-- 
2.13.6