toybox: tar: Fix support for long names

Pathnames may be longer than the name field in the header, so use
strncpy() instead of xstrncpy() to avoid bailing out.

Also add unit tests to ensure proper handling of short and long
pathnames.

Change-Id: Id025891993746889564b479e5185cf9721b54a55

2 files changed, 18 insertions, 1 deletions

diff --git a/tests/tar.test b/tests/tar.test
index 872e7c02..5b10b014 100755
--- a/tests/tar.test
+++ b/tests/tar.test
@@ -71,3 +71,20 @@ rm -rf temp_dir
 mkdir dir/dir1 -p 
 echo "Inside dir/dir1" > dir/dir1/file ; echo "Hello Inside dir" > dir/file
 testing "Extraction on STDOUT : -O" " tar -czf dir.tgz dir/ ; rm -rf dir ; tar -xf dir.tgz -O ; [ -e 'Inside dir/dir1/\nHello Inside dir\n' ] && echo 'yes'; rm -rf dir.tgz "  "" "" ""
+
+#Creating short filename
+f="filename_with_100_chars_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
+echo "This is testdata" > $f
+testing "tar shortname filename" "tar -cf testFile.tar $f && [ -e testFile.tar ] && echo 'yes'; rm -f $f; tar -xf testFile.tar && [ -f $f ] && cat $f && strings testFile.tar | grep -o LongLink; rm -f testFile.tar; rm -f $f" "yes\nThis is testdata\n" "" ""
+
+#Creating long filename
+f="filename_with_101_chars_xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
+echo "This is testdata" > $f
+testing "tar longname filename" "tar -cf testFile.tar $f && [ -e testFile.tar ] && echo 'yes'; rm -f $f; tar -xf testFile.tar && [ -f $f ] && cat $f && strings testFile.tar | grep -o LongLink; rm -f testFile.tar; rm -f $f" "yes\nThis is testdata\nLongLink\n" "" ""
+
+#Creating long pathname
+d="dirname_with_50_chars_xxxxxxxxxxxxxxxxxxxxxxxxxxxx"
+f="filename_with_50_chars_xxxxxxxxxxxxxxxxxxxxxxxxxxx"
+mkdir $d
+echo "This is testdata" > $d/$f
+testing "tar longname pathname" "tar -cf testFile.tar $d/$f && [ -e testFile.tar ] && echo 'yes'; rm -rf $d; tar -xf testFile.tar && [ -f $d/$f ] && cat $d/$f && strings testFile.tar | grep -o LongLink; rm -f testFile.tar; rm -rf $d" "yes\nThis is testdata\nLongLink\n" "" ""
diff --git a/toys/pending/tar.c b/toys/pending/tar.c
index 6140ea5d..4f4de0b5 100644
--- a/toys/pending/tar.c
+++ b/toys/pending/tar.c
@@ -190,7 +190,7 @@ static void add_file(struct archive_handler *tar, char **nam, struct stat *st)
   }
 
   memset(&hdr, 0, sizeof(hdr));
-  xstrncpy(hdr.name, hname, sizeof(hdr.name));
+  strncpy(hdr.name, hname, sizeof(hdr.name));
   itoo(hdr.mode, sizeof(hdr.mode), st->st_mode &07777);
   itoo(hdr.uid, sizeof(hdr.uid), st->st_uid);
   itoo(hdr.gid, sizeof(hdr.gid), st->st_gid);