Index: stream.c
===================================================================
RCS file: /home/ncvs/projects/csup/stream.c,v
retrieving revision 1.53
diff -u -r1.53 stream.c
--- stream.c	11 Feb 2006 01:17:04 -0000	1.53
+++ stream.c	17 Mar 2006 23:33:50 -0000
@@ -81,6 +81,14 @@
 	STREAM_FLUSH_CLOSING
 } stream_flush_t;
 
+/* Internal error codes */
+#define STREAM_ERR_READ		(-1)	/* Error reading from stream */
+#define STREAM_ERR_WRITE	(-2)	/* Error writing to stream */
+#define STREAM_ERR_FLUSH	(-3)	/* Error flushing stream */
+#define STREAM_ERR_SYNC		(-4)	/* Error synchronizing stream */
+#define STREAM_ERR_TRUNCATE	(-5)	/* Error truncating stream */
+#define STREAM_ERR_SEEK		(-6)	/* Error seeking in stream */
+
 /*
  * This is because buf_new() will always allocate size + 1 bytes,
  * so our buffer sizes will still be power of 2 values.
@@ -96,6 +104,7 @@
 
 struct stream {
 	void *cookie;
+	int error;
 	int fd;
 	struct buf *rdbuf;
 	struct buf *wrbuf;
@@ -300,6 +309,7 @@
 	else
 		stream->wrbuf = NULL;
 	stream->cookie = NULL;
+	stream->error = 0;
 	stream->fd = -1;
 	stream->readfn = readfn;
 	stream->writefn = writefn;
@@ -437,8 +447,11 @@
 	rdbuf = stream->rdbuf;
 	if (buf_count(rdbuf) == 0) {
 		ret = stream_fill(stream);
-		if (ret <= 0)
+		if (ret <= 0) {
+			if (ret < 0) 
+				stream->error = STREAM_ERR_READ;
 			return (-1);
+		}
 	}
 	n = min(size, buf_count(rdbuf));
 	memcpy(buf, rdbuf->buf + rdbuf->off, n);
@@ -475,14 +488,19 @@
 	buf = stream->rdbuf;
 	if (buf_count(buf) == 0) {
 		n = stream_fill(stream);
-		if (n <= 0)
+		if (n <= 0) {
+			if (n < 0)
+				stream->error = STREAM_ERR_READ;
 			return (NULL);
+		}
 	}
 	cp = memchr(buf->buf + buf->off, '\n', buf_count(buf));
 	for (done = buf_count(buf); cp == NULL; done += n) {
 		n = stream_fill(stream);
-		if (n < 0)
+		if (n < 0) {
+			stream->error = STREAM_ERR_READ;
 			return (NULL);
+		}
 		if (n == 0)
 			/* Last line of the stream. */
 			cp = buf->buf + buf->off + buf->in - 1;
@@ -518,8 +536,10 @@
 		buf_grow(buf, nbytes);
 	if (nbytes > buf_avail(buf)) {
 		error = stream_flush_int(stream, STREAM_FLUSH_NORMAL);
-		if (error)
-			return (-1);
+		if (error) {
+			stream->error = STREAM_ERR_WRITE;
+			return (error);
+		}
 	}
 	memcpy(buf->buf + buf->off + buf->in, src, nbytes);
 	buf_more(buf, nbytes);
@@ -546,8 +566,10 @@
 			buf_grow(buf, ret + 1);
 		if ((unsigned)ret >= buf_avail(buf)) {
 			error = stream_flush_int(stream, STREAM_FLUSH_NORMAL);
-			if (error)
-				return (-1);
+			if (error) {
+				stream->error = STREAM_ERR_WRITE;
+				return (error);
+			}
 		}
 		goto again;
 	}
@@ -562,6 +584,8 @@
 	int error;
 
 	error = stream_flush_int(stream, STREAM_FLUSH_NORMAL);
+	if (error)
+		stream->error = STREAM_ERR_FLUSH;
 	return (error);
 }
 
@@ -611,6 +635,8 @@
 	if (error)
 		return (-1);
 	error = fsync(stream->fd);
+	if (error)
+		stream->error = STREAM_ERR_SYNC;
 	return (error);
 }
 
@@ -628,6 +654,8 @@
 	if (error)
 		return (-1);
 	error = ftruncate(stream->fd, size);
+	if (error)
+		stream->error = STREAM_ERR_TRUNCATE;
 	return (error);
 }
 
@@ -646,9 +674,13 @@
 	if (error)
 		return (-1);
 	error = fstat(stream->fd, &sb);
-	if (error)
+	if (error) {
+		stream->error = STREAM_ERR_TRUNCATE;
 		return (-1);
+	}
 	error = stream_truncate(stream, sb.st_size + off);
+	if (error)
+		stream->error = STREAM_ERR_TRUNCATE;
 	return (error);
 }
 
@@ -670,6 +702,8 @@
 			return (error);
 	}
 	error = lseek(stream->fd, 0, SEEK_SET);
+	if (error)
+		stream->error = STREAM_ERR_SEEK;
 	return (error);
 }
 
@@ -679,6 +713,36 @@
 {
 
 	return (stream->eof);
+}
+
+/* Give a descriptive error message */
+int
+stream_error(struct stream *stream)
+{
+
+	switch (stream->error) {
+		case STREAM_ERR_READ:
+			lprintf(-1, "Error reading from stream\n");
+			break;
+		case STREAM_ERR_WRITE:
+			lprintf(-1, "Error writing to stream\n");
+			break;
+		case STREAM_ERR_FLUSH:
+			lprintf(-1, "Error flushing stream\n");
+			break;
+		case STREAM_ERR_SEEK:
+			lprintf(-1, "Error seeking in stream\n");
+			break;
+		case STREAM_ERR_SYNC:
+			lprintf(-1, "Error synchronizing stream\n");
+			break;
+		case STREAM_ERR_TRUNCATE:
+			lprintf(-1, "Error truncating stream\n");
+			break;
+		default:
+			assert(stream->error == 0);
+	}
+	return (stream->error);
 }
 
 /* Close a stream and free any resources held by it. */
Index: stream.h
===================================================================
RCS file: /home/ncvs/projects/csup/stream.h,v
retrieving revision 1.21
diff -u -r1.21 stream.h
--- stream.h	10 Feb 2006 18:18:47 -0000	1.21
+++ stream.h	17 Mar 2006 23:33:50 -0000
@@ -65,6 +65,7 @@
 int		 stream_truncate_rel(struct stream *, off_t);
 int		 stream_rewind(struct stream *);
 int		 stream_eof(struct stream *);
+int		 stream_error(struct stream *);
 int		 stream_close(struct stream *);
 int		 stream_filter_start(struct stream *, stream_filter_t, void *);
 void		 stream_filter_stop(struct stream *);