From bc4d023a3810a7da6ede2cc522cdc34fa3129378 Mon Sep 17 00:00:00 2001
From: Sergey Poznyakoff <gray@gnu.org>
Date: Fri, 25 Jan 2019 14:34:13 +0200
Subject: Improve error checking in stream writing functions.

* libmailutils/stream/stream.c (mu_stream_write): Return EIO on
short writes if pnwritten is NULL.
* libmailutils/stream/streamcpy.c (mu_stream_copy): Likewise (if
source stream size is known.
---
 libmailutils/stream/stream.c    |  5 +++++
 libmailutils/stream/streamcpy.c | 43 +++++++++++++++++++++--------------------
 2 files changed, 27 insertions(+), 21 deletions(-)

diff --git a/libmailutils/stream/stream.c b/libmailutils/stream/stream.c
index de995aa57..8c9cbb6e0 100644
--- a/libmailutils/stream/stream.c
+++ b/libmailutils/stream/stream.c
@@ -1030,6 +1030,11 @@ mu_stream_write (mu_stream_t stream, const void *buf, size_t size,
 	}
       if (pnwritten)
 	*pnwritten = nbytes;
+      else if (nbytes < size)
+	{
+	  rc = EIO;
+	  mu_stream_seterr (stream, rc, 1);
+	}
     }
   return rc;
 }
diff --git a/libmailutils/stream/streamcpy.c b/libmailutils/stream/streamcpy.c
index 3270ee9fb..aaf0e7273 100644
--- a/libmailutils/stream/streamcpy.c
+++ b/libmailutils/stream/streamcpy.c
@@ -38,7 +38,7 @@ mu_stream_copy (mu_stream_t dst, mu_stream_t src, mu_off_t size,
   size_t bufsize, n;
   char *buf;
   mu_off_t total = 0;
-  
+
   if (pcsz)
     *pcsz = 0;
   if (size == 0)
@@ -56,7 +56,7 @@ mu_stream_copy (mu_stream_t dst, mu_stream_t src, mu_off_t size,
 	default:
 	  return status;
 	}
-      
+
       if (size)
 	{
 	  mu_off_t pos;
@@ -68,7 +68,7 @@ mu_stream_copy (mu_stream_t dst, mu_stream_t src, mu_off_t size,
 		return ESPIPE;
 	      size -= pos;
 	      break;
-      
+
 	    case EACCES:
 	      mu_stream_clearerr (src);
 	    case ENOSYS:
@@ -90,21 +90,26 @@ mu_stream_copy (mu_stream_t dst, mu_stream_t src, mu_off_t size,
       return ENOMEM;
 
   if (size)
-    while (size)
-      {
-	size_t rdsize = bufsize < size ? bufsize : size;
+    {
+      while (size)
+	{
+	  size_t rdsize = bufsize < size ? bufsize : size;
 
-	status = mu_stream_read (src, buf, rdsize, &n);
-	if (status)
-	  break;
-	if (n == 0)
-	  break;
-	status = mu_stream_write (dst, buf, n, NULL);
-	if (status)
-	  break;
-	size -= n;
-	total += n;
-      }
+	  status = mu_stream_read (src, buf, rdsize, &n);
+	  if (status)
+	    break;
+	  if (n == 0)
+	    break;
+	  status = mu_stream_write (dst, buf, n, NULL);
+	  if (status)
+	    break;
+	  size -= n;
+	  total += n;
+	}
+
+      if (!pcsz && size)
+	status = EIO;
+    }
   else
     while ((status = mu_stream_read (src, buf, bufsize, &n)) == 0
 	   && n > 0)
@@ -124,7 +129,3 @@ mu_stream_copy (mu_stream_t dst, mu_stream_t src, mu_off_t size,
   free (buf);
   return status;
 }
-      
-
-  
-  
-- 
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