logger: use xgetlogin from pwdutils.

It defined its own xgetlogin, which queried geteuid() instead of getuid(),
with a fallback to "<someone>" when lookup fails. This has been the case
since the function was introduced in
019b97024f, so geteuid() has always been
used. Since using geteuid for identification isn't consistent with the
rest of util-linux, switching to xgetlogin(), which uses getuid(),
should be correct.

Signed-off-by: Érico Nogueira <erico.erc@gmail.com>

misc-utils/Makemodule.am

@@ -28,7 +28,7 @@ usrbin_exec_PROGRAMS += logger
 MANPAGES += misc-utils/logger.1
 dist_noinst_DATA += misc-utils/logger.1.adoc
 logger_SOURCES = misc-utils/logger.c lib/strutils.c lib/strv.c
-logger_LDADD = $(LDADD)
+logger_LDADD = $(LDADD) libcommon.la
 logger_CFLAGS = $(AM_CFLAGS)
 if HAVE_SYSTEMD
 logger_LDADD += $(SYSTEMD_LIBS) $(SYSTEMD_DAEMON_LIBS) $(SYSTEMD_JOURNAL_LIBS)

misc-utils/logger.c

@@ -63,6 +63,7 @@
 #include "xalloc.h"
 #include "strv.h"
 #include "list.h"
+#include "pwdutils.h"
 
 #define	SYSLOG_NAMES
 #include <syslog.h>
@@ -393,16 +394,6 @@ static int journald_entry(struct logger_ctl *ctl, FILE *fp)
 }
 #endif
 
-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;
-}
-
 /* this creates a timestamp based on current time according to the
  * fine rules of RFC3164, most importantly it ensures in a portable
  * way that the month day is correctly written (with a SP instead
@@ -927,6 +918,8 @@ static void logger_open(struct logger_ctl *ctl)
 					      syslog_local_header;
 	if (!ctl->tag)
 		ctl->tag = xgetlogin();
+	if (!ctl->tag)
+		ctl->tag = "<someone>";
 
 	generate_syslog_header(ctl);
 }