From c6018240f8c3d6e01da23b70c9dd254bda2d8759 Mon Sep 17 00:00:00 2001
From: Alejandro Colomar <alx@kernel.org>
Date: Sat, 18 May 2024 21:38:24 +0200
Subject: [PATCH] lib/, src/: Use strrspn() instead of its pattern

This requires changing isspace(3) calls to an explicit accept string,
and I chose " \t\n" for it (as is done in other parts of this project),
which isn't exactly the same, but we probably don't want other
isspace(3) characters in those files, so it should work.

Signed-off-by: Alejandro Colomar <alx@kernel.org>
---
 lib/fields.c      |  9 ++++-----
 lib/getdef.c      | 10 ++--------
 src/login_nopam.c |  6 ++----
 src/suauth.c      | 10 +++++-----
 4 files changed, 13 insertions(+), 22 deletions(-)

diff --git a/lib/fields.c b/lib/fields.c
index 53929248..b6d2fa14 100644
--- a/lib/fields.c
+++ b/lib/fields.c
@@ -14,7 +14,10 @@
 #include <ctype.h>
 #include <string.h>
 #include <stdio.h>
+
 #include "prototypes.h"
+#include "string/strchr/strrspn.h"
+
 
 /*
  * valid_field - insure that a field contains all legal characters
@@ -89,11 +92,7 @@ void change_field (char *buf, size_t maxsize, const char *prompt)
 		 * makes it possible to change the field to empty, by
 		 * entering a space.  --marekm
 		 */
-
-		while (newf < cp && isspace (cp[-1])) {
-			cp--;
-		}
-		*cp = '\0';
+		*strrspn(newf, " \t\n") = '\0';
 
 		cp = newf;
 		while (isspace (*cp)) {
diff --git a/lib/getdef.c b/lib/getdef.c
index 459fdc99..91f40702 100644
--- a/lib/getdef.c
+++ b/lib/getdef.c
@@ -31,6 +31,7 @@
 #include "string/sprintf/xasprintf.h"
 #include "string/strchr/stpcspn.h"
 #include "string/strchr/stpspn.h"
+#include "string/strchr/strrspn.h"
 
 
 /*
@@ -528,7 +529,6 @@ static void def_load (void)
 #else /* USE_ECONF */
 static void def_load (void)
 {
-	int i;
 	FILE *fp;
 	char buf[1024], *name, *value, *s;
 
@@ -560,13 +560,7 @@ static void def_load (void)
 		/*
 		 * Trim trailing whitespace.
 		 */
-		for (i = (ptrdiff_t) strlen (buf) - 1; i >= 0; --i) {
-			if (!isspace (buf[i])) {
-				break;
-			}
-		}
-		i++;
-		buf[i] = '\0';
+		*strrspn(buf, " \t\n") = '\0';
 
 		/*
 		 * Break the line into two fields.
diff --git a/src/login_nopam.c b/src/login_nopam.c
index 1a2b1736..03a2871f 100644
--- a/src/login_nopam.c
+++ b/src/login_nopam.c
@@ -57,6 +57,7 @@
 #include <arpa/inet.h>		/* for inet_ntoa() */
 
 #include "sizeof.h"
+#include "string/strchr/strrspn.h"
 
 #if !defined(MAXHOSTNAMELEN) || (MAXHOSTNAMELEN < 64)
 #undef MAXHOSTNAMELEN
@@ -110,10 +111,7 @@ int login_access (const char *user, const char *from)
 			if (line[0] == '#') {
 				continue;	/* comment line */
 			}
-			while (end > 0 && isspace (line[end - 1])) {
-				end--;
-			}
-			line[end] = '\0';	/* strip trailing whitespace */
+			*strrspn(line, " \t\n") = '\0';
 			if (line[0] == '\0') {	/* skip blank lines */
 				continue;
 			}
diff --git a/src/suauth.c b/src/suauth.c
index 4d631904..ed45a856 100644
--- a/src/suauth.c
+++ b/src/suauth.c
@@ -8,13 +8,17 @@
  */
 
 #include <config.h>
+
 #include <errno.h>
 #include <grp.h>
 #include <pwd.h>
 #include <stdio.h>
 #include <sys/types.h>
+
 #include "defines.h"
 #include "prototypes.h"
+#include "string/strchr/strrspn.h"
+
 
 #ifndef SUAUTHFILE
 #define SUAUTHFILE "/etc/suauth"
@@ -77,11 +81,7 @@ int check_su_auth (const char *actual_id,
 			continue;
 		}
 
-		while (endline > 0 && (temp[endline - 1] == ' '
-				       || temp[endline - 1] == '\t'
-				       || temp[endline - 1] == '\n'))
-			endline--;
-		temp[endline] = '\0';
+		*strrspn(temp, " \t\n") = '\0';
 
 		posn = 0;
 		while (temp[posn] == ' ' || temp[posn] == '\t')