From patchwork Wed Apr  7 21:02:33 2010
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Subject: [5/8] char: Let writers know how much data was written in case of
 errors
From: Amit Shah <amit.shah@redhat.com>
X-Patchwork-Id: 49646
Message-Id: <1270674156-9345-6-git-send-email-amit.shah@redhat.com>
To: qemu list <qemu-devel@nongnu.org>
Cc: Amit Shah <amit.shah@redhat.com>, Paul Brook <paul@codesourcery.com>,
 "Michael S. Tsirkin" <mst@redhat.com>,
 Gerd Hoffmann <kraxel@redhat.com>, Juan Quintela <quintela@redhat.com>
Date: Thu,  8 Apr 2010 02:32:33 +0530

On writing errors, we just returned -1 even if some bytes were already
written out. Ensure we return the number of bytes written before we
return the error (on a subsequent call to qemu_chr_write()).

Signed-off-by: Amit Shah <amit.shah@redhat.com>

---
qemu-char.c |    9 +++++++--
 1 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/qemu-char.c b/qemu-char.c
index 048da3f..208466f 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -502,8 +502,13 @@ static int unix_write(int fd, const uint8_t *buf, int len1)
     while (len > 0) {
         ret = write(fd, buf, len);
         if (ret < 0) {
-            if (errno != EINTR && errno != EAGAIN)
-                return -1;
+            if (errno != EINTR && errno != EAGAIN) {
+                if (len1 - len) {
+                    return len1 - len;
+                } else {
+                    return -1;
+                }
+            }
         } else if (ret == 0) {
             break;
         } else {