From 9bea60d43abaa6f325df4a428cd4a164711ae857 Mon Sep 17 00:00:00 2001
From: hyung-hwan <hyunghwan.chung@gmail.com>
Date: Mon, 5 Dec 2022 16:04:11 +0000
Subject: [PATCH] untar - improved EOF marker handling

---
 bin/untar.c   |  4 ++--
 lib/hio-tar.h |  3 ++-
 lib/tar.c     | 20 +++++++++++++-------
 3 files changed, 17 insertions(+), 10 deletions(-)

diff --git a/bin/untar.c b/bin/untar.c
index 5b184cf..e907ab5 100644
--- a/bin/untar.c
+++ b/bin/untar.c
@@ -34,7 +34,7 @@ int main (int argc, char* argv[])
 	if (!fp)
 	{
 		fprintf (stderr, "Error: unable to open file %s\n", argv[1]);
-		hio_tar_close (hio);
+		hio_tar_close (untar);
 		hio_close (hio);
 		return -1;
 	}
@@ -43,7 +43,7 @@ int main (int argc, char* argv[])
 	while (!feof(fp) && !ferror(fp))
 	{
 		int n;
-		char buf[99]; /* TODO: use a different buffer size???*/
+		char buf[512]; /* TODO: use a different buffer size???*/
 		n = fread(buf, 1, sizeof(buf), fp);
 		if (n > 0) 
 		{
diff --git a/lib/hio-tar.h b/lib/hio-tar.h
index 60fbae8..0791548 100644
--- a/lib/hio-tar.h
+++ b/lib/hio-tar.h
@@ -75,7 +75,8 @@ enum hio_tar_state_t
 {
 	HIO_TAR_STATE_START,
 	HIO_TAR_STATE_FILE,
-	HIO_TAR_STATE_END
+	HIO_TAR_STATE_END_1,
+	HIO_TAR_STATE_END_2
 };
 typedef enum hio_tar_state_t hio_tar_state_t;
 
diff --git a/lib/tar.c b/lib/tar.c
index 3cb0c54..dc04de4 100644
--- a/lib/tar.c
+++ b/lib/tar.c
@@ -245,9 +245,8 @@ printf("process_header...\n");
 	/* all-zero byte block ends the archive */
 	if (HIO_MEMCMP(hdr, _end_block, HIO_TAR_BLKSIZE) == 0) 
 	{
-/* TODO: is it correct? */
-printf ("end of input\n");
-		tar->state = HIO_TAR_STATE_END;
+		/* two all-zero blocks are expected as the EOF indicator */
+		tar->state = HIO_TAR_STATE_END_1;
 	}
 	else
 	{
@@ -362,11 +361,10 @@ static int process_content (hio_tar_t* tar)
 
 int hio_tar_feed (hio_tar_t* tar, const void* ptr, hio_oow_t len)
 {
-printf ("feed len = %d\n", len);
 	if (!ptr)
 	{
 		/* EOF indicator */
-		if (tar->state != HIO_TAR_STATE_END || tar->blk.len > 0)
+		if ((tar->state != HIO_TAR_STATE_END_1 && tar->state != HIO_TAR_STATE_END_2) || tar->blk.len > 0)
 		{
 			/* ERROR - premature end of file */
 			hio_seterrbfmt (tar->hio, HIO_EINVAL, "premature end of feed");
@@ -393,17 +391,25 @@ printf ("feed len = %d\n", len);
 			{
 				case HIO_TAR_STATE_START:
 					if (process_header(tar) <= -1) return -1;
-	if (tar->state == HIO_TAR_STATE_END) printf ("remaining data len %d\n", len);
 					break;
 
 				case HIO_TAR_STATE_FILE:
 					if (process_content(tar) <= -1) return -1;
 					break;
 
-				case HIO_TAR_STATE_END:
+				case HIO_TAR_STATE_END_1:
+					if (HIO_MEMCMP(tar->blk.buf, _end_block, HIO_TAR_BLKSIZE) == 0)
+					{
+						tar->state = HIO_TAR_STATE_END_2;
+						break;
+					}
+					/* fall thru here for the trailing garbage error */
+
+				case HIO_TAR_STATE_END_2:
 					/* garbage after the final ending block */
 					hio_seterrbfmt (tar->hio, HIO_EINVAL, "trailing garbage at the end of feed");
 					return -1;
+					break;
 			}
 
 			tar->blk.len = 0;