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, 12 insertions, 5 deletions

diff --git a/lib/libfetch/http.c b/lib/libfetch/http.c
index b33d6f1..557ff26 100644
--- a/lib/libfetch/http.c
+++ b/lib/libfetch/http.c
@@ -196,6 +196,8 @@ http_growbuf(struct httpio *io, size_t len)
 static int
 http_fillbuf(struct httpio *io, size_t len)
 {
+	ssize_t nbytes;
+
 	if (io->error)
 		return (-1);
 	if (io->eof)
@@ -204,10 +206,11 @@ http_fillbuf(struct httpio *io, size_t len)
 	if (io->chunked == 0) {
 		if (http_growbuf(io, len) == -1)
 			return (-1);
-		if ((io->buflen = fetch_read(io->conn, io->buf, len)) == -1) {
-			io->error = 1;
+		if ((nbytes = fetch_read(io->conn, io->buf, len)) == -1) {
+			io->error = errno;
 			return (-1);
 		}
+		io->buflen = nbytes;
 		io->bufpos = 0;
 		return (io->buflen);
 	}
@@ -227,10 +230,11 @@ http_fillbuf(struct httpio *io, size_t len)
 		len = io->chunksize;
 	if (http_growbuf(io, len) == -1)
 		return (-1);
-	if ((io->buflen = fetch_read(io->conn, io->buf, len)) == -1) {
-		io->error = 1;
+	if ((nbytes = fetch_read(io->conn, io->buf, len)) == -1) {
+		io->error = errno;
 		return (-1);
 	}
+	io->buflen = nbytes;
 	io->chunksize -= io->buflen;
 
 	if (io->chunksize == 0) {
@@ -272,8 +276,11 @@ http_readfn(void *v, char *buf, int len)
 		io->bufpos += l;
 	}
 
-	if (!pos && io->error)
+	if (!pos && io->error) {
+		if (io->error == EINTR)
+			io->error = 0;
 		return (-1);
+	}
 	return (pos);
 }