diff --git a/lib/eventlog/eventlog.c b/lib/eventlog/eventlog.c
index ae16e2e6e..1f0183b1b 100644
--- a/lib/eventlog/eventlog.c
+++ b/lib/eventlog/eventlog.c
@@ -361,10 +361,7 @@ exec_mailer(int pipein)
 	sudo_debug_exit(__func__, __FILE__, __LINE__, sudo_debug_subsys);
 	_exit(127);
     }
-    if ((argv[0] = strrchr(mpath, '/')))
-	argv[0]++;
-    else
-	argv[0] = (char *)mpath;
+    argv[0] = sudo_basename(mpath);
 
     i = 1;
     if ((p = strtok_r(mflags, " \t", &last))) {
diff --git a/lib/util/Makefile.in b/lib/util/Makefile.in
index a928a39f5..7396c70ef 100644
--- a/lib/util/Makefile.in
+++ b/lib/util/Makefile.in
@@ -136,7 +136,7 @@ MKTEMP_TEST_OBJS = mktemp_test.lo mktemp.lo
 
 PARSELN_TEST_OBJS = parseln_test.lo parseln.lo
 
-PROGNAME_TEST_OBJS = progname_test.lo progname.lo
+PROGNAME_TEST_OBJS = progname_test.lo progname.lo basename.lo
 
 CONF_TEST_OBJS = conf_test.lo sudo_conf.lo
 
diff --git a/lib/util/progname.c b/lib/util/progname.c
index beb2925f0..a5f93b25f 100644
--- a/lib/util/progname.c
+++ b/lib/util/progname.c
@@ -53,8 +53,7 @@ sudo_getprogname(void)
 void
 sudo_setprogname(const char *name)
 {
-    const char *slash = strrchr(name, '/');
-    __progname = slash ? slash + 1 : name;
+    __progname = sudo_basename(name);
 }
 #endif
 
@@ -69,9 +68,7 @@ initprogname2(const char *name, const char * const * allowed)
 	name = progname;
     } else {
 	/* Make sure user-specified name is relative. */
-	const char *slash = strrchr(name, '/');
-	if (slash != NULL)
-	    name = slash + 1;
+	name = sudo_basename(name);
     }
 
     /* Check for libtool prefix and strip it if present. */
diff --git a/lib/util/regress/progname/progname_test.c b/lib/util/regress/progname/progname_test.c
index 0ac539868..f6a9d48e3 100644
--- a/lib/util/regress/progname/progname_test.c
+++ b/lib/util/regress/progname/progname_test.c
@@ -37,12 +37,8 @@ main(int argc, char *argv[])
 {
     char *progbase = "progname_test";
 
-    if (argc > 0) {
-	if ((progbase = strrchr(argv[0], '/')) != NULL)
-	    progbase++;
-	else
-	    progbase = argv[0];
-    }
+    if (argc > 0)
+	progbase = sudo_basename(argv[0]);
     initprogname(progbase);
 
     /* Make sure getprogname() matches basename of argv[0]. */
diff --git a/lib/util/sudo_conf.c b/lib/util/sudo_conf.c
index 388042362..b0237babd 100644
--- a/lib/util/sudo_conf.c
+++ b/lib/util/sudo_conf.c
@@ -516,33 +516,25 @@ struct sudo_conf_debug_file_list *
 sudo_conf_debug_files_v1(const char *progname)
 {
     struct sudo_conf_debug *debug_spec;
-    size_t prognamelen, progbaselen;
-    const char *progbase = progname;
+    const char *progbase;
     debug_decl(sudo_conf_debug_files, SUDO_DEBUG_UTIL);
 
     /* Determine basename if program is fully qualified (like for plugins). */
-    prognamelen = progbaselen = strlen(progname);
-    if (*progname == '/') {
-	progbase = strrchr(progname, '/');
-	progbaselen = strlen(++progbase);
-    }
+    progbase = progname[0] == '/' ? sudo_basename(progname) : progname;
+
     /* Convert sudoedit -> sudo. */
-    if (progbaselen > 4 && strcmp(progbase + 4, "edit") == 0) {
-	progbaselen -= 4;
-    }
+    if (strcmp(progbase, "sudoedit") == 0)
+	progbase = "sudo";
+
     TAILQ_FOREACH(debug_spec, &sudo_conf_data.debugging, entries) {
 	const char *prog = progbase;
-	size_t len = progbaselen;
 
 	if (debug_spec->progname[0] == '/') {
 	    /* Match fully-qualified name, if possible. */
 	    prog = progname;
-	    len = prognamelen;
 	}
-	if (strncmp(debug_spec->progname, prog, len) == 0 &&
-	    debug_spec->progname[len] == '\0') {
+	if (strcmp(debug_spec->progname, prog) == 0)
 	    debug_return_ptr(&debug_spec->debug_files);
-	}
     }
     debug_return_ptr(NULL);
 }
diff --git a/lib/util/util.exp.in b/lib/util/util.exp.in
index de7c140b0..583e6dfae 100644
--- a/lib/util/util.exp.in
+++ b/lib/util/util.exp.in
@@ -1,6 +1,6 @@
 @COMPAT_EXP@initprogname
 initprogname2
-sudo_basename
+sudo_basename_v1
 sudo_conf_askpass_path_v1
 sudo_conf_clear_paths_v1
 sudo_conf_debug_files_v1
diff --git a/plugins/sudoers/audit.c b/plugins/sudoers/audit.c
index f72c4d4cb..3ee26b89a 100644
--- a/plugins/sudoers/audit.c
+++ b/plugins/sudoers/audit.c
@@ -225,9 +225,7 @@ audit_to_eventlog(struct eventlog *evlog, char * const command_info[],
 	    case 'i':
 		if (strncmp(*cur, "iolog_path=", sizeof("iolog_path=") - 1) == 0) {
 		    evlog->iolog_path = *cur + sizeof("iolog_path=") - 1;
-		    evlog->iolog_file = strrchr(evlog->iolog_path, '/');
-		    if (evlog->iolog_file != NULL)
-			evlog->iolog_file++;
+		    evlog->iolog_file = sudo_basename(evlog->iolog_path);
 		    continue;
 		}
 		break;
diff --git a/plugins/sudoers/find_path.c b/plugins/sudoers/find_path.c
index 5c44b4ff2..e1b6a0135 100644
--- a/plugins/sudoers/find_path.c
+++ b/plugins/sudoers/find_path.c
@@ -57,18 +57,13 @@ cmnd_allowed(char *cmnd, size_t cmnd_size, const char *runchroot,
 	debug_return_bool(true);	/* nothing to check */
 
     /* We compare the base names to avoid excessive stat()ing. */
-    if ((cmnd_base = strrchr(cmnd, '/')) == NULL)
-	debug_return_bool(false);	/* can't happen */
-    cmnd_base++;
+    cmnd_base = sudo_basename(cmnd);
 
     for (al = allowlist; *al != NULL; al++) {
 	const char *base, *path = *al;
 	struct stat sb;
 
-	if ((base = strrchr(path, '/')) == NULL)
-	    continue;		/* XXX - warn? */
-	base++;
-
+	base = sudo_basename(path);
 	if (strcmp(cmnd_base, base) != 0)
 	    continue;
 
diff --git a/plugins/sudoers/iolog.c b/plugins/sudoers/iolog.c
index 75af12d83..cec82a4d2 100644
--- a/plugins/sudoers/iolog.c
+++ b/plugins/sudoers/iolog.c
@@ -352,9 +352,7 @@ iolog_deserialize_info(struct log_details *details, char * const user_info[],
 		evlog->iolog_path = strdup(*cur + sizeof("iolog_path=") - 1);
 		if (evlog->iolog_path == NULL)
 		    goto oom;
-		evlog->iolog_file = strrchr(evlog->iolog_path, '/');
-		if (evlog->iolog_file != NULL)
-		    evlog->iolog_file++;
+		evlog->iolog_file = sudo_basename(evlog->iolog_path);
 		continue;
 	    }
 	    if (strncmp(*cur, "iolog_stdin=", sizeof("iolog_stdin=") - 1) == 0) {
diff --git a/plugins/sudoers/match_command.c b/plugins/sudoers/match_command.c
index ff8e8dc92..91193bc53 100644
--- a/plugins/sudoers/match_command.c
+++ b/plugins/sudoers/match_command.c
@@ -384,11 +384,9 @@ command_matches_glob(const char *sudoers_cmnd, const char *sudoers_args,
      */
     dlen = strlen(sudoers_cmnd);
     if (sudoers_cmnd[dlen - 1] != '/') {
-	if ((base = strrchr(sudoers_cmnd, '/')) != NULL) {
-	    base++;
-	    if (!has_meta(base) && strcmp(user_base, base) != 0)
-		debug_return_bool(false);
-	}
+	base = sudo_basename(sudoers_cmnd);
+	if (!has_meta(base) && strcmp(user_base, base) != 0)
+	    debug_return_bool(false);
     }
 
     /* Make sudoers_cmnd relative to the new root, if any. */
@@ -472,10 +470,7 @@ command_matches_glob(const char *sudoers_cmnd, const char *sudoers_args,
 	    }
 
 	    /* Only proceed if user_base and basename(cp) match */
-	    if ((base = strrchr(cp, '/')) != NULL)
-		base++;
-	    else
-		base = cp;
+	    base = sudo_basename(cp);
 	    if (strcmp(user_base, base) != 0)
 		continue;
 
@@ -531,10 +526,7 @@ command_matches_normal(const char *sudoers_cmnd, const char *sudoers_args,
     }
 
     /* Only proceed if user_base and basename(sudoers_cmnd) match */
-    if ((base = strrchr(sudoers_cmnd, '/')) == NULL)
-	base = sudoers_cmnd;
-    else
-	base++;
+    base = sudo_basename(sudoers_cmnd);
     if (strcmp(user_base, base) != 0)
 	debug_return_bool(false);
 
diff --git a/plugins/sudoers/sudoers.c b/plugins/sudoers/sudoers.c
index f9d1a9f19..e8eb38e0b 100644
--- a/plugins/sudoers/sudoers.c
+++ b/plugins/sudoers/sudoers.c
@@ -928,7 +928,7 @@ set_cmnd(void)
 	debug_return_int(NOT_FOUND_ERROR);
     }
 
-    /* Default value for cmnd, overridden below. */
+    /* Default value for cmnd, overridden by set_cmnd_path() below. */
     if (user_cmnd == NULL)
 	user_cmnd = NewArgv[0];
 
@@ -966,11 +966,7 @@ set_cmnd(void)
 		debug_return_int(NOT_FOUND_ERROR);
 	}
     }
-
-    if ((user_base = strrchr(user_cmnd, '/')) != NULL)
-	user_base++;
-    else
-	user_base = user_cmnd;
+    user_base = sudo_basename(user_cmnd);
 
     /* Convert "sudo sudoedit" -> "sudoedit" */
     if (ISSET(sudo_mode, MODE_RUN) && strcmp(user_base, "sudoedit") == 0) {
diff --git a/plugins/sudoers/testsudoers.c b/plugins/sudoers/testsudoers.c
index 1217da7f4..ebe489e57 100644
--- a/plugins/sudoers/testsudoers.c
+++ b/plugins/sudoers/testsudoers.c
@@ -209,10 +209,7 @@ main(int argc, char *argv[])
     } else {
 	user_name = *argv++;
 	user_cmnd = *argv++;
-	if ((p = strrchr(user_cmnd, '/')) != NULL)
-	    user_base = p + 1;
-	else
-	    user_base = user_cmnd;
+	user_base = sudo_basename(user_cmnd);
 	argc -= 2;
     }
     if ((sudo_user.pw = sudo_getpwnam(user_name)) == NULL)
@@ -447,12 +444,8 @@ open_sudoers(const char *file, bool doedit, bool *keepopen)
     const char *base;
     debug_decl(open_sudoers, SUDOERS_DEBUG_UTIL);
 
-    base = strrchr(file, '/');
-    if (base != NULL)
-	base++;
-    else
-	base = file;
-
+    /* Report errors using the basename for consistent test output. */
+    base = sudo_basename(file);
     switch (sudo_secure_file(file, sudoers_uid, sudoers_gid, &sb)) {
 	case SUDO_PATH_SECURE:
 	    fp = fopen(file, "r");
diff --git a/plugins/sudoers/visudo.c b/plugins/sudoers/visudo.c
index 8d40f332c..653697289 100644
--- a/plugins/sudoers/visudo.c
+++ b/plugins/sudoers/visudo.c
@@ -381,15 +381,11 @@ static char *lineno_editors[] = {
 static bool
 editor_supports_plus(const char *editor)
 {
-    const char *editor_base = strrchr(editor, '/');
-    const char *cp;
+    const char *cp, *editor_base;
     char **av;
     debug_decl(editor_supports_plus, SUDOERS_DEBUG_UTIL);
 
-    if (editor_base != NULL)
-	editor_base++;
-    else
-	editor_base = editor;
+    editor_base = sudo_basename(editor);
     if (*editor_base == 'r')
 	editor_base++;
 
@@ -760,10 +756,7 @@ install_sudoers(struct sudoersfile *sp, bool oldperms)
 	      sp->tpath, sp->path);
 
 	    /* Build up argument vector for the command */
-	    if ((av[0] = strrchr(_PATH_MV, '/')) != NULL)
-		av[0]++;
-	    else
-		av[0] = _PATH_MV;
+	    av[0] = sudo_basename(_PATH_MV);
 	    av[1] = sp->tpath;
 	    av[2] = sp->path;
 	    av[3] = NULL;
diff --git a/src/sudo_edit.c b/src/sudo_edit.c
index b3eea9821..41fc61c3a 100644
--- a/src/sudo_edit.c
+++ b/src/sudo_edit.c
@@ -132,20 +132,17 @@ set_tmpdir(struct sudo_cred *user_cred)
 static int
 sudo_edit_mktemp(const char *ofile, char **tfile)
 {
-    const char *cp, *suff;
+    const char *base, *suff;
     int len, tfd;
     debug_decl(sudo_edit_mktemp, SUDO_DEBUG_EDIT);
 
-    if ((cp = strrchr(ofile, '/')) != NULL)
-	cp++;
-    else
-	cp = ofile;
-    suff = strrchr(cp, '.');
+    base = sudo_basename(ofile);
+    suff = strrchr(base, '.');
     if (suff != NULL) {
 	len = asprintf(tfile, "%s/%.*sXXXXXXXX%s", edit_tmpdir,
-	    (int)(size_t)(suff - cp), cp, suff);
+	    (int)(size_t)(suff - base), base, suff);
     } else {
-	len = asprintf(tfile, "%s/%s.XXXXXXXX", edit_tmpdir, cp);
+	len = asprintf(tfile, "%s/%s.XXXXXXXX", edit_tmpdir, base);
     }
     if (len == -1) {
 	sudo_warnx(U_("%s: %s"), __func__, U_("unable to allocate memory"));
diff --git a/src/sudo_noexec.c b/src/sudo_noexec.c
index 6025d9148..3a2abdfdd 100644
--- a/src/sudo_noexec.c
+++ b/src/sudo_noexec.c
@@ -188,17 +188,10 @@ FN_NAME(wordexp)(const char *words, wordexp_t *we, int flags)
     void *fn = NULL;
     int idx = 0;
 
-    name = strrchr(myname, '/');
-    if (name != NULL)
-	myname = name + 1;
-
     /* Search for wordexp() but skip this shared object. */
+    myname = sudo_basename(myname);
     while (shl_get(idx++, &desc) == 0) {
-	name = strrchr(desc->filename, '/');
-	if (name == NULL)
-		name = desc->filename;
-	else
-		name++;
+	name = sudo_basename(desc->filename);
 	if (strcmp(name, myname) == 0)
 	    continue;
 	if (shl_findsym(&desc->handle, "wordexp", TYPE_PROCEDURE, &fn) == 0)