On Fri, Mar 13, 2026 at 10:27:32PM +0100, Alexander Bluhm wrote:
> On Fri, Mar 13, 2026 at 03:50:21PM -0400, Dave Voutila wrote:
> > Better version with input from brynet@ on setting O_CLOEXEC at open
> > time.
>
> works for me, OK bluhm@
>
> > diff refs/heads/master refs/heads/vmd-pledge
> > commit - f0fb81d370539aeb26fe6a527b3437ebad8ce8b4
> > commit + fce4c500fcfc68d1339c617f0f9380b8429a7e7f
> > blob - 31120d064d64b5ca0a2b4570bc06662ad2d35b23
> > blob + 4c0d2a5487ba6d9673f069c7a700a5d4c18a9227
> > --- usr.sbin/vmd/vmm.c
> > +++ usr.sbin/vmd/vmm.c
> > @@ -49,6 +49,7 @@ int terminate_vm(struct vm_terminate_params *);
> > int get_info_vm(struct privsep *, struct imsg *, int);
> > int opentap(char *);
> >
> > +int dev_null = -1;
> > extern struct vmd *env;
> >
> > static struct privsep_proc procs[] = {
> > @@ -68,6 +69,16 @@ vmm_run(struct privsep *ps, struct privsep_proc *p, vo
> > fatal("failed to initialize configuration");
> >
> > /*
> > + * Early-open /dev/null so we can dup2(2) std{in,out,err}
> > + * after forking to create child processes.
> > + */
> > + if (!env->vmd_debug) {
> > + dev_null = open("/dev/null", O_RDWR|O_CLOEXEC, 0);
> > + if (dev_null == -1)
> > + fatal("/dev/null");
> > + }
> > +
> > + /*
> > * We aren't root, so we can't chroot(2). Use unveil(2) instead.
> > */
> > if (unveil(env->argv0, "x") == -1)
> > @@ -589,7 +600,7 @@ vmm_start_vm(struct imsg *imsg, uint32_t *id, pid_t *p
> > {
> > struct vmd_vm *vm;
> > char *nargv[10], num[32], vmm_fd[32], psp_fd[32];
> > - int fd, ret = EINVAL;
> > + int ret = EINVAL;
> > int fds[2];
> > pid_t vm_pid;
> > size_t i, j, sz;
> > @@ -694,13 +705,12 @@ vmm_start_vm(struct imsg *imsg, uint32_t *id, pid_t *p
> > close_fd(PROC_PARENT_SOCK_FILENO);
> >
> > /* Detach from terminal. */
> > - if (!env->vmd_debug && (fd =
> > - open("/dev/null", O_RDWR, 0)) != -1) {
> > - dup2(fd, STDIN_FILENO);
> > - dup2(fd, STDOUT_FILENO);
> > - dup2(fd, STDERR_FILENO);
> > - if (fd > 2)
> > - close(fd);
> > + if (!env->vmd_debug) {
> > + dup2(dev_null, STDIN_FILENO);
> > + dup2(dev_null, STDOUT_FILENO);
> > + dup2(dev_null, STDERR_FILENO);
> > + if (dev_null > 2)
> > + close(dev_null);
> > }
> >
> > if (env->vmd_psp_fd > 0)
> >
> >
>
Works for me too.
