[Qemu-devel] [PATCH 01/15] Introduce qemu_write_full()

["Kirill A. Shutemov" <kirill@shutemov.name>]

A variant of write(2) which handles partial write.

Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
---
 osdep.c       |   27 +++++++++++++++++++++++++++
 qemu-common.h |    2 ++
 2 files changed, 29 insertions(+), 0 deletions(-)

diff --git a/osdep.c b/osdep.c
index e4836e7..8ae48fe 100644
--- a/osdep.c
+++ b/osdep.c
@@ -243,6 +243,33 @@ int qemu_open(const char *name, int flags, ...)
     return ret;
 }
 
+/*
+ * A variant of write(2) which handles partial write.
+ *
+ * Return the number of bytes transferred.
+ * Set errno if fewer than `count' bytes are written.
+ */
+size_t qemu_write_full(int fd, const void *buf, size_t count)
+{
+    ssize_t ret;
+    size_t total = 0;
+
+    while (count) {
+        ret = write(fd, buf, count);
+        if (ret < 0) {
+            if (errno == EINTR)
+                continue;
+            break;
+        }
+
+        count -= ret;
+        buf += ret;
+        total += ret;
+    }
+
+    return total;
+}
+
 #ifndef _WIN32
 /*
  * Creates a pipe with FD_CLOEXEC set on both file descriptors
diff --git a/qemu-common.h b/qemu-common.h
index 8630f8c..7231348 100644
--- a/qemu-common.h
+++ b/qemu-common.h
@@ -160,6 +160,8 @@ void qemu_mutex_lock_iothread(void);
 void qemu_mutex_unlock_iothread(void);
 
 int qemu_open(const char *name, int flags, ...);
+size_t qemu_write_full(int fd, const void *buf, size_t count)
+    __attribute__ ((warn_unused_result));
 void qemu_set_cloexec(int fd);
 
 #ifndef _WIN32
-- 
1.6.5.7