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. (eblake@redhat.com) -Fix dupfd leak in qemu_dup(). (eblake@redhat.com) -Always set O_CLOEXEC in qemu_dup(). (kwolf@redhat.com) -Change name of qemu_dup() to qemu_dup_flags(). (kwolf@redhat.com)
@@ -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. -- Eric Blake eblake@redhat.com +1-919-301-3266 Libvirt virtualization library http://libvirt.org