On 08/11/2012 07:14 AM, Corey Bryant wrote:
When qemu_open is passed a filename of the "/dev/fdset/nnn"
format (where nnn is the fdset ID), an fd with matching access
mode flags will be searched for within the specified monitor
fd set. If the fd is found, a dup of the fd will be returned
from qemu_open.
v9:
-Drop fdset refcount and check dup_fds instead. (address@hidden)
-Fix dupfd leak in qemu_dup(). (address@hidden)
-Always set O_CLOEXEC in qemu_dup(). (address@hidden)
-Change name of qemu_dup() to qemu_dup_flags(). (address@hidden)
@@ -87,6 +146,40 @@ int qemu_open(const char *name, int flags, ...)
int ret;
int mode = 0;
+#ifndef _WIN32
+ const char *fdset_id_str;
+
+ /* Attempt dup of fd from fd set */
+ if (strstart(name, "/dev/fdset/", &fdset_id_str)) {
+ int64_t fdset_id;
+ int fd, dupfd;
+
+ fdset_id = qemu_parse_fdset(fdset_id_str);
+ if (fdset_id == -1) {
+ errno = EINVAL;
+ return -1;
+ }
+
+ fd = monitor_fdset_get_fd(fdset_id, flags);
+ if (fd == -1) {
+ return -1;
+ }
+
+ dupfd = qemu_dup_flags(fd, flags);
+ if (fd == -1) {
Checking the wrong condition:
s/fd/dupfd/
+ return -1;
+ }
+
+ ret = monitor_fdset_dup_fd_add(fdset_id, dupfd);
+ if (ret == -1) {
+ close(dupfd);
+ return -1;
This function appears to promise a reasonable errno on failure.
However, I don't think monitor_fdset_dup_fd_add guarantees a reasonable
errno, and even if it does, close() can corrupt errno. I think that
prior to returning here, you either need an explicit errno=ENOMEM, or
fix monitor_fdset_dup_fd to guarantee a nice errno, plus a save and
restore of errno here. Unless no one cares about errno on failure, in
which case your earlier errno=EINVAL can be dropped.