Re: [libvirt] [PATCH v9 6/7] block: Enable qemu_open/close to work with fd sets

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(a)redhat.com) -Fix dupfd leak in qemu_dup(). (eblake(a)redhat.com) -Always set O_CLOEXEC in qemu_dup(). (kwolf(a)redhat.com) -Change name of qemu_dup() to qemu_dup_flags(). (kwolf(a)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) {

+ return -1; + } + + ret = monitor_fdset_dup_fd_add(fdset_id, dupfd); + if (ret == -1) { + close(dupfd); + return -1;