Update close(2) checking

Check for close(2) failure at more places closing a file descriptor
written to.

Also ignore failures with errno set to EINTR (see man:close(2) for
details).

src/useradd.c

@@ -2041,7 +2041,7 @@ static void faillog_reset (uid_t uid)
 		         Prog, (unsigned long) uid, strerror (errno));
 		SYSLOG ((LOG_WARN, "failed to reset the faillog entry of UID %lu", (unsigned long) uid));
 	}
-	if (close (fd) != 0) {
+	if (close (fd) != 0 && errno != EINTR) {
 		fprintf (stderr,
 		         _("%s: failed to close the faillog file for UID %lu: %s\n"),
 		         Prog, (unsigned long) uid, strerror (errno));
@@ -2087,7 +2087,7 @@ static void lastlog_reset (uid_t uid)
 		SYSLOG ((LOG_WARN, "failed to reset the lastlog entry of UID %lu", (unsigned long) uid));
 		/* continue */
 	}
-	if (close (fd) != 0) {
+	if (close (fd) != 0 && errno != EINTR) {
 		fprintf (stderr,
 		         _("%s: failed to close the lastlog file for UID %lu: %s\n"),
 		         Prog, (unsigned long) uid, strerror (errno));
@@ -2442,8 +2442,12 @@ static void create_mail (void)
 		perror(_("Setting mailbox file permissions"));
 	}
 
-	fsync(fd);
-	close(fd);
+	if (fsync(fd) != 0) {
+		perror (_("Synchronize mailbox file"));
+	}
+	if (close(fd) != 0 && errno != EINTR) {
+		perror (_("Closing mailbox file"));
+	}
 #ifdef WITH_SELINUX
 	/* Reset SELinux to create files with default contexts */
 	if (reset_selinux_file_context() != 0) {

src/usermod.c

@@ -1963,7 +1963,11 @@ static void update_lastlog (void)
 		}
 	}
 
-	(void) close (fd);
+	if (close (fd) != 0 && errno != EINTR) {
+		fprintf (stderr,
+		         _("%s: failed to copy the lastlog entry of user %ju to user %ju: %s\n"),
+		         Prog, (uintmax_t) user_id, (uintmax_t) user_newid, strerror (errno));
+	}
 }
 #endif /* ENABLE_LASTLOG */
 
@@ -2023,7 +2027,11 @@ static void update_faillog (void)
 		}
 	}
 
-	(void) close (fd);
+	if (close (fd) != 0 && errno != EINTR) {
+		fprintf (stderr,
+		         _("%s: failed to copy the faillog entry of user %ju to user %ju: %s\n"),
+		         Prog, (uintmax_t) user_id, (uintmax_t) user_newid, strerror (errno));
+	}
 }
 
 #ifndef NO_MOVE_MAILBOX