Patchwork [V10,01/13] Implement qemu_read_full

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Submitter Mohan Kumar M
Date March 31, 2011, 8:21 a.m.
Message ID <1301559700-6742-2-git-send-email-mohan@in.ibm.com>
Download mbox | patch
Permalink /patch/89033/
State New
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Mohan Kumar M - March 31, 2011, 8:21 a.m.
Add qemu_read_full function

Signed-off-by: M. Mohan Kumar <mohan@in.ibm.com>
---
 osdep.c       |   32 ++++++++++++++++++++++++++++++++
 qemu-common.h |    2 ++
 2 files changed, 34 insertions(+), 0 deletions(-)

Patch

diff --git a/osdep.c b/osdep.c
index 327583b..8d84a88 100644
--- a/osdep.c
+++ b/osdep.c
@@ -127,6 +127,38 @@  ssize_t qemu_write_full(int fd, const void *buf, size_t count)
 }
 
 /*
+ * A variant of read(2) which handles interrupted read.
+ * Simlar to qemu_write_full function
+ *
+ * Return the number of bytes read.
+ *
+ * This function does not work with non-blocking fd's.
+ * errno is set if fewer than `count' bytes are read because of any
+ * error
+ */
+ssize_t qemu_read_full(int fd, void *buf, size_t count)
+{
+    ssize_t ret = 0;
+    ssize_t total = 0;
+
+    while (count) {
+        ret = read(fd, buf, count);
+        if (ret <= 0) {
+            if (errno == EINTR) {
+                continue;
+            }
+            break;
+        }
+
+        count -= ret;
+        buf += ret;
+        total += ret;
+    }
+
+    return total;
+}
+
+/*
  * Opens a socket with FD_CLOEXEC set
  */
 int qemu_socket(int domain, int type, int protocol)
diff --git a/qemu-common.h b/qemu-common.h
index 40dad52..325b16a 100644
--- a/qemu-common.h
+++ b/qemu-common.h
@@ -207,6 +207,8 @@  void qemu_mutex_unlock_iothread(void);
 int qemu_open(const char *name, int flags, ...);
 ssize_t qemu_write_full(int fd, const void *buf, size_t count)
     QEMU_WARN_UNUSED_RESULT;
+ssize_t qemu_read_full(int fd, void *buf, size_t count)
+    QEMU_WARN_UNUSED_RESULT;
 void qemu_set_cloexec(int fd);
 
 #ifndef _WIN32