On Tue, Oct 13, 2026 at 2:02 AM Filip Hejsek <[email protected]> wrote: > > Use qemu_dup() to ensure the cloexec flag is set on dup'd fds. > > The following dup() instances were left unchanged: > > FILE REASON > util/osdep.c implementation of qemu_dup > migration/cpr-exec.c fd is intentionally kept across exec > {linux,bsd}-user/* guest syscalls > tests/* left for future work > > Signed-off-by: Filip Hejsek <[email protected]>
Reviewed-by: Marc-André Lureau <[email protected]> > --- > For each call I replaced, I checked how the resulting fd is used > afterwards. In summary: > > hw/virtio/virtio.c: > the fd is passed to memory_region_init_ram_from_fd, used for mmaping > > io/channel-file.c: > the fd is passed to qio_channel_file_new_fd, used for reading/writing > > qemu-nbd.c: > the fd is stored into old_stderr, then dup2'd back to STDERR_FILENO > > system/vl.c: > no change in behavior, the code was already setting the cloexec flag > > ui/dmabuf.c: > the function is called by qemu_spice_gl_update, which passes the fds > to SPICE server > > These uses shouldn't require keeping the fd open across exec. > > Changes in v2: > - Replace the use in qemu-nbd.c too > - Changed commit message > - Link to v1: > https://lore.kernel.org/qemu-devel/[email protected] > --- > hw/virtio/virtio.c | 2 +- > io/channel-file.c | 2 +- > qemu-nbd.c | 2 +- > system/vl.c | 9 +-------- > ui/dmabuf.c | 2 +- > 5 files changed, 5 insertions(+), 12 deletions(-) > > diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c > index c9f9e5b511..70779fbd56 100644 > --- a/hw/virtio/virtio.c > +++ b/hw/virtio/virtio.c > @@ -3204,7 +3204,7 @@ VirtioSharedMemoryMapping > *virtio_shared_memory_mapping_new(uint8_t shmid, > return NULL; > } > > - fd = dup(fd); > + fd = qemu_dup(fd); > if (fd < 0) { > error_report("Failed to duplicate fd: %s", strerror(errno)); > return NULL; > diff --git a/io/channel-file.c b/io/channel-file.c > index 5cef75a67c..3f707e80c9 100644 > --- a/io/channel-file.c > +++ b/io/channel-file.c > @@ -48,7 +48,7 @@ qio_channel_file_new_fd(int fd) > QIOChannelFile * > qio_channel_file_new_dupfd(int fd, Error **errp) > { > - int newfd = dup(fd); > + int newfd = qemu_dup(fd); > > if (newfd < 0) { > error_setg_errno(errp, errno, "Could not dup FD %d", fd); > diff --git a/qemu-nbd.c b/qemu-nbd.c > index ed5895861b..db1a70b008 100644 > --- a/qemu-nbd.c > +++ b/qemu-nbd.c > @@ -975,7 +975,7 @@ int main(int argc, char **argv) > > /* Remember parent's stderr if we will be restoring it. */ > if (opts.verbose /* fork_process is set */) { > - opts.old_stderr = dup(STDERR_FILENO); > + opts.old_stderr = qemu_dup(STDERR_FILENO); > if (opts.old_stderr < 0) { > error_report("Could not dup original stderr: %s", > strerror(errno)); > diff --git a/system/vl.c b/system/vl.c > index 468a9fc247..9381e3d7f7 100644 > --- a/system/vl.c > +++ b/system/vl.c > @@ -614,14 +614,7 @@ static int parse_add_fd(void *opaque, QemuOpts *opts, > Error **errp) > return -1; > } > > -#ifdef F_DUPFD_CLOEXEC > - dupfd = fcntl(fd, F_DUPFD_CLOEXEC, 0); > -#else > - dupfd = dup(fd); > - if (dupfd != -1) { > - qemu_set_cloexec(dupfd); > - } > -#endif > + dupfd = qemu_dup(fd); > if (dupfd == -1) { > error_setg_errno(errp, errno, "error duplicating fd"); > return -1; > diff --git a/ui/dmabuf.c b/ui/dmabuf.c > index 497f82cc61..6d5dffdf84 100644 > --- a/ui/dmabuf.c > +++ b/ui/dmabuf.c > @@ -95,7 +95,7 @@ void qemu_dmabuf_dup_fds(QemuDmaBuf *dmabuf, int *fds, int > nfds) > assert(nfds >= dmabuf->num_planes); > > for (i = 0; i < dmabuf->num_planes; i++) { > - fds[i] = dmabuf->fd[i] >= 0 ? dup(dmabuf->fd[i]) : -1; > + fds[i] = dmabuf->fd[i] >= 0 ? qemu_dup(dmabuf->fd[i]) : -1; > } > } > > > --- > base-commit: 615ece3c406b262996e569f29ea6eed0d81c4d8d > change-id: 20261012-use-qemu-dup-38628dbac3ee > > Best regards, > -- > Filip Hejsek <[email protected]> >
