[Qemu-devel] [PATCH v2 3/4] osdep: Enable qemu_open to dup pre-opened fd

[Corey Bryant <coreyb@linux.vnet.ibm.com>]

This patch adds support to qemu_open to dup(X) a pre-opened file
descriptor if the filename is of the format /dev/fd/X.

This can be used when QEMU is restricted from opening files, and
the management application opens files on QEMU's behalf.

v2:
 -Get rid of file_open and move dup code to qemu_open (kwolf@redhat.com)
 -Use strtol wrapper instead of atoi (kwolf@redhat.com)

Signed-off-by: Corey Bryant <coreyb@linux.vnet.ibm.com>
---
 osdep.c |   13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/osdep.c b/osdep.c
index 3e6bada..c17cdcb 100644
--- a/osdep.c
+++ b/osdep.c
@@ -82,6 +82,19 @@ int qemu_open(const char *name, int flags, ...)
     int ret;
     int mode = 0;
 
+#ifndef _WIN32
+    const char *p;
+
+    /* Attempt dup of fd for pre-opened file */
+    if (strstart(name, "/dev/fd/", &p)) {
+        ret = qemu_parse_fd(p);
+        if (ret == -1) {
+            return -1;
+        }
+        return dup(ret);
+    }
+#endif
+
     if (flags & O_CREAT) {
         va_list ap;
 
-- 
1.7.10.2