[Qemu-devel] [PATCH v3 1/4] 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, 7 insertions(+), 2 deletions(-)

diff --git a/qemu-char.c b/qemu-char.c
index 05df971..6aaa362 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 {
-- 
1.6.2.5