From 49a1995049546ffd943953c320c8409082e3d167 Mon Sep 17 00:00:00 2001
From: Alejandro Colomar <alx@kernel.org>
Date: Thu, 4 Jul 2024 18:47:58 +0200
Subject: [PATCH] lib/, src/: Use strncmp(3) instead of explicit byte
 comparisons

This is simpler to read, IMO.

Signed-off-by: Alejandro Colomar <alx@kernel.org>
---
 lib/utmp.c    | 12 ++++++------
 src/login.c   |  2 +-
 src/logoutd.c |  5 +++--
 3 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/lib/utmp.c b/lib/utmp.c
index 4aa2a9096..43cd6aac1 100644
--- a/lib/utmp.c
+++ b/lib/utmp.c
@@ -210,7 +210,7 @@ get_session_host(char **out, pid_t main_pid)
 	ut = get_current_utmp(main_pid);
 
 #if defined(HAVE_STRUCT_UTMPX_UT_HOST)
-	if ((ut != NULL) && (ut->ut_host[0] != '\0')) {
+	if ((ut != NULL) && strncmp(ut->ut_host, "", countof(ut->ut_host)) != 0) {
 		*out = XSTRNDUP(ut->ut_host);
 	} else {
 		*out = NULL;
@@ -281,7 +281,7 @@ prepare_utmp(const char *name, const char *line, const char *host,
 	if (NULL != host && !streq(host, ""))
 		hostname = xstrdup(host);
 #if defined(HAVE_STRUCT_UTMPX_UT_HOST)
-	else if (NULL != ut && '\0' != ut->ut_host[0])
+	else if (NULL != ut && strncmp(ut->ut_host, "", countof(ut->ut_host)) != 0)
 		hostname = XSTRNDUP(ut->ut_host);
 #endif
 
@@ -436,12 +436,12 @@ active_sessions_count(const char *name, unsigned long limit)
 		if (USER_PROCESS != ut->ut_type) {
 			continue;
 		}
-		if ('\0' == ut->ut_user[0]) {
+		if (strncmp(ut->ut_user, "", countof(ut->ut_user)) == 0)
 			continue;
-		}
-		if (strncmp (name, ut->ut_user, sizeof (ut->ut_user)) != 0) {
+
+		if (strncmp(ut->ut_user, name, countof(ut->ut_user)) != 0)
 			continue;
-		}
+
 		count++;
 		if (count > limit) {
 			break;
diff --git a/src/login.c b/src/login.c
index 7b567aae8..aff812e2e 100644
--- a/src/login.c
+++ b/src/login.c
@@ -1200,7 +1200,7 @@ int main (int argc, char **argv)
 			printf (_("Last login: %s on %s"),
 			        ptime, ll.ll_line);
 #ifdef HAVE_LL_HOST		/* __linux__ || SUN4 */
-			if ('\0' != ll.ll_host[0]) {
+			if (strncmp(ll.ll_host, "", countof(ll.ll_host)) != 0) {
 				printf (_(" from %.*s"),
 				        (int) sizeof ll.ll_host, ll.ll_host);
 			}
diff --git a/src/logoutd.c b/src/logoutd.c
index 3efcd8468..fc08fa1fd 100644
--- a/src/logoutd.c
+++ b/src/logoutd.c
@@ -13,6 +13,7 @@
 #include <fcntl.h>
 #include <signal.h>
 #include <stdio.h>
+#include <string.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <utmpx.h>
@@ -178,9 +179,9 @@ main(int argc, char **argv)
 			if (ut->ut_type != USER_PROCESS) {
 				continue;
 			}
-			if (ut->ut_user[0] == '\0') {
+			if (strncmp(ut->ut_user, "", countof(ut->ut_user)) == 0)
 				continue;
-			}
+
 			if (check_login (ut)) {
 				continue;
 			}
-- 
2.47.3