From patchwork Tue May  4 07:17:18 2010
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Subject: [v4, 1/5] char: Let writers know how much data was written in case of
 errors
Date: Mon, 03 May 2010 21:17:18 -0000
From: Amit Shah <amit.shah@redhat.com>
X-Patchwork-Id: 51569
Message-Id: <1272957442-7832-2-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>,
 Gerd Hoffmann <kraxel@redhat.com>, Juan Quintela <quintela@redhat.com>

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 ac65a1c..bc76000 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -522,8 +522,13 @@ 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 {