Fix two issues related to the use of SIGINFO in fetch(1) to display

progress information.  The first is that fetch_read() (used in the HTTP
code but not the FTP code) can enter an infinite loop if it has previously
been interrupted by a signal.  The second is that when it is interrupted,
fetch_read() will discard any data it may have read up to that point.
Luckily, both bugs are extremely timing-sensitive and therefore difficult
to trigger.

PR:		bin/153240
Submitted by:	Mark <markjdb@gmail.com>
MFC after:	3 weeks

1 files changed, 7 insertions, 0 deletions

diff --git a/lib/libfetch/common.h b/lib/libfetch/common.h
index 35e0dfd..241dbbf 100644
--- a/lib/libfetch/common.h
+++ b/lib/libfetch/common.h
@@ -52,6 +52,13 @@ struct fetchconn {
 	size_t		 bufsize;	/* buffer size */
 	size_t		 buflen;	/* length of buffer contents */
 	int		 err;		/* last protocol reply code */
+	struct {			/* data cached after an interrupted
+					   read */
+		char	*buf;
+		size_t	 size;
+		size_t	 pos;
+		size_t	 len;
+	} cache;
 #ifdef WITH_SSL
 	SSL		*ssl;		/* SSL handle */
 	SSL_CTX		*ssl_ctx;	/* SSL context */