[Qemu-devel] [PATCH v5 3/6] char: Let writers know how much data was written in case of errors

[Amit Shah <amit.shah@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, 8 insertions(+), 1 deletions(-)

diff --git a/qemu-char.c b/qemu-char.c
index 65cb3f5..97f2ef6 100644
--- a/qemu-char.c
+++ b/qemu-char.c
@@ -507,6 +507,9 @@ int send_all(int fd, const void *buf, int len1)
     while (len > 0) {
         ret = send(fd, buf, len, 0);
         if (ret < 0) {
+            if (len1 - len) {
+                return len1 - len;
+            }
             errno = WSAGetLastError();
             if (errno != WSAEWOULDBLOCK) {
                 return -1;
@@ -531,8 +534,12 @@ 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)
+            if (len1 - len) {
+                return len1 - len;
+            }
+            if (errno != EINTR && errno != EAGAIN) {
                 return -1;
+            }
         } else if (ret == 0) {
             break;
         } else {
-- 
1.6.2.5