We should distinguish between a real truncated case and EOF after

BZ_STREAM_END triggered re-init.  Do it by introducing a new flag
to represent the 'cold' case after bzip2 state is reinitialized.

This fixes regression reported on -current@ as well as another one
I found during twiddling with gzip.

Reported by:	swell.k gmail.com
MFC after:	1 week

1 files changed, 14 insertions, 3 deletions

diff --git a/usr.bin/gzip/unbzip2.c b/usr.bin/gzip/unbzip2.c
index 4835325..c744e56 100644
--- a/usr.bin/gzip/unbzip2.c
+++ b/usr.bin/gzip/unbzip2.c
@@ -36,7 +36,7 @@
 static off_t
 unbzip2(int in, int out, char *pre, size_t prelen, off_t *bytes_in)
 {
-	int		ret, end_of_file;
+	int		ret, end_of_file, cold = 0;
 	off_t		bytes_out = 0;
 	bz_stream	bzs;
 	static char	*inbuf, *outbuf;
@@ -86,8 +86,18 @@ unbzip2(int in, int out, char *pre, size_t prelen, off_t *bytes_in)
 	        switch (ret) {
 	        case BZ_STREAM_END:
 	        case BZ_OK:
-	                if (ret == BZ_OK && end_of_file)
-	                        maybe_err("read");
+	                if (ret == BZ_OK && end_of_file) {
+				/*
+				 * If we hit this after a stream end, consider
+				 * it as the end of the whole file and don't
+				 * bail out.
+				 */
+				if (cold == 1)
+					ret = BZ_STREAM_END;
+				else
+					maybe_errx("truncated file");
+			}
+			cold = 0;
 	                if (!tflag && bzs.avail_out != BUFLEN) {
 				ssize_t	n;
 
@@ -100,6 +110,7 @@ unbzip2(int in, int out, char *pre, size_t prelen, off_t *bytes_in)
 				if (BZ2_bzDecompressEnd(&bzs) != BZ_OK ||
 				    BZ2_bzDecompressInit(&bzs, 0, 0) != BZ_OK)
 					maybe_errx("bzip2 re-init");
+				cold = 1;
 				ret = BZ_OK;
 			}
 			break;