From 5454df9c3110f7742500e5d2af1ea300924c0120 Mon Sep 17 00:00:00 2001
From: "G.raud Meyer" <graud@gmx.com>
Date: Thu, 29 Mar 2018 13:28:10 +0200
Subject: [PATCH] rename: check source file access early

This change makes rename detect inexisting files given on the command
line and consider them faliures.  This is particularly useful with
--no-act (to detect extraneous arguments).

It also prevents skipping non existing files (when the modified name
happens to exist).  This makes --verbose not print skipping messages of
false positives (the access error is printed instead).
---
 misc-utils/rename.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/misc-utils/rename.c b/misc-utils/rename.c
index 147e54fe9..9983ad2a9 100644
--- a/misc-utils/rename.c
+++ b/misc-utils/rename.c
@@ -18,6 +18,7 @@ for i in $@; do N=`echo "$i" | sed "s/$FROM/$TO/g"`; mv "$i" "$N"; done
 #include <stdlib.h>
 #include <errno.h>
 #include <getopt.h>
+#include <fcntl.h>
 #include <unistd.h>
 #include <sys/types.h>
 #include <sys/stat.h>
@@ -59,6 +60,11 @@ static int do_symlink(char *from, char *to, char *s, int verbose, int noact, int
 	int ret = 1;
 	struct stat sb;
 
+	if (faccessat(AT_FDCWD, s, F_OK, AT_SYMLINK_NOFOLLOW) != 0) {
+		warn(_("%s: not accessible"), s);
+		return 2;
+	}
+
 	if (lstat(s, &sb) == -1) {
 		warn(_("stat of %s failed"), s);
 		return 2;
@@ -106,12 +112,18 @@ static int do_file(char *from, char *to, char *s, int verbose, int noact, int no
 	char *newname = NULL, *file=NULL;
 	int ret = 1;
 
+	if (access(s, F_OK) != 0) {
+		warn(_("%s: not accessible"), s);
+		return 2;
+	}
+
 	if (strchr(from, '/') == NULL && strchr(to, '/') == NULL)
 		file = strrchr(s, '/');
 	if (file == NULL)
 		file = s;
 	if (string_replace(from, to, file, s, &newname))
 		return 0;
+
 	if (nooverwrite && access(newname, F_OK) == 0) {
 		if (verbose)
 			printf(_("Skipping existing file: `%s'\n"), newname);