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From:
Dave Voutila <dv@sisu.io>
Subject:
disambiguate fd variable naming in vmd
To:
tech@openbsd.org
Date:
Mon, 13 Jul 2026 09:45:32 -0400

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  • Dave Voutila:

    disambiguate fd variable naming in vmd

Boring but helpful diff leading up to my sharing a much larger one. The
global instance of struct vmd uses its vmd_fd member for multiple things
depending on the vmd process. In one case, it's a socket(2)...in
another, an open vmm(4).

This redesigns struct vmd to have distinct members named based on usage
to make vmd slightly easier to reason about.

Bonus tweaks: properly initializes the SEV, ptm, and socket fd's to -1
and changes a logic check from the strange semantic of "> -1" to "!=
-1". (At no point should 0 be a valid fd value for the psp or vmm
devices.)

ok?


diffstat refs/heads/master refs/heads/vmd-fd-cleanup-simple
 M  usr.sbin/vmd/priv.c    |  12+  12-
 M  usr.sbin/vmd/virtio.c  |   1+   1-
 M  usr.sbin/vmd/vm.c      |   5+   5-
 M  usr.sbin/vmd/vmd.c     |  11+   7-
 M  usr.sbin/vmd/vmd.h     |   4+   3-
 M  usr.sbin/vmd/vmm.c     |   7+   7-

6 files changed, 40 insertions(+), 35 deletions(-)

diff refs/heads/master refs/heads/vmd-fd-cleanup-simple
commit - 9598e7ed943eac95d9532381b8c8e3bb46321fbd
commit + 291de405160c12f78e9103b08983b3dae43d372e
blob - 5c7338ba24c7d867fde84a2b1d1eddcdac03b5a7
blob + d8739aa6010babc401b91f0d0277ff6ac7793657
--- usr.sbin/vmd/priv.c
+++ usr.sbin/vmd/priv.c
@@ -63,11 +63,11 @@ priv_run(struct privsep *ps, struct privsep_proc *p, v
 	 */

 	/* Open our own socket for generic interface ioctls */
-	if ((env->vmd_fd = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
+	if ((env->vmd_sock_fd = socket(AF_INET, SOCK_DGRAM, 0)) == -1)
 		fatal("socket");

 	/* But we need a different fd for IPv6 */
-	if ((env->vmd_fd6 = socket(AF_INET6, SOCK_DGRAM, 0)) == -1)
+	if ((env->vmd_sock_fd6 = socket(AF_INET6, SOCK_DGRAM, 0)) == -1)
 		fatal("socket6");
 }

@@ -124,13 +124,13 @@ priv_dispatch_parent(int fd, struct privsep_proc *p, s
 		/* Set the interface description */
 		strlcpy(ifr.ifr_name, vfr.vfr_name, sizeof(ifr.ifr_name));
 		ifr.ifr_data = (caddr_t)vfr.vfr_value;
-		if (ioctl(env->vmd_fd, SIOCSIFDESCR, &ifr) == -1)
+		if (ioctl(env->vmd_sock_fd, SIOCSIFDESCR, &ifr) == -1)
 			log_warn("SIOCSIFDESCR");
 		break;
 	case IMSG_VMDOP_PRIV_IFRDOMAIN:
 		strlcpy(ifr.ifr_name, vfr.vfr_name, sizeof(ifr.ifr_name));
 		ifr.ifr_rdomainid = vfr.vfr_id;
-		if (ioctl(env->vmd_fd, SIOCSIFRDOMAIN, &ifr) == -1)
+		if (ioctl(env->vmd_sock_fd, SIOCSIFRDOMAIN, &ifr) == -1)
 			log_warn("SIOCSIFRDOMAIN");
 		break;
 	case IMSG_VMDOP_PRIV_IFADD:
@@ -143,14 +143,14 @@ priv_dispatch_parent(int fd, struct privsep_proc *p, s
 		    sizeof(ifbr.ifbr_name));
 		strlcpy(ifbr.ifbr_ifsname, vfr.vfr_value,
 		    sizeof(ifbr.ifbr_ifsname));
-		if (ioctl(env->vmd_fd, SIOCBRDGADD, &ifbr) == -1 &&
+		if (ioctl(env->vmd_sock_fd, SIOCBRDGADD, &ifbr) == -1 &&
 		    errno != EEXIST)
 			log_warn("SIOCBRDGADD");
 		break;
 	case IMSG_VMDOP_PRIV_IFEXISTS:
 		/* Determine if bridge exists */
 		strlcpy(ifr.ifr_name, vfr.vfr_name, sizeof(ifr.ifr_name));
-		if (ioctl(env->vmd_fd, SIOCGIFFLAGS, &ifr) == -1)
+		if (ioctl(env->vmd_sock_fd, SIOCGIFFLAGS, &ifr) == -1)
 			fatalx("%s: bridge \"%s\" does not exist",
 			    __func__, vfr.vfr_name);
 		break;
@@ -158,7 +158,7 @@ priv_dispatch_parent(int fd, struct privsep_proc *p, s
 	case IMSG_VMDOP_PRIV_IFDOWN:
 		/* Set the interface status */
 		strlcpy(ifr.ifr_name, vfr.vfr_name, sizeof(ifr.ifr_name));
-		if (ioctl(env->vmd_fd, SIOCGIFFLAGS, &ifr) == -1) {
+		if (ioctl(env->vmd_sock_fd, SIOCGIFFLAGS, &ifr) == -1) {
 			log_warn("SIOCGIFFLAGS");
 			break;
 		}
@@ -166,7 +166,7 @@ priv_dispatch_parent(int fd, struct privsep_proc *p, s
 			ifr.ifr_flags |= IFF_UP;
 		else
 			ifr.ifr_flags &= ~IFF_UP;
-		if (ioctl(env->vmd_fd, SIOCSIFFLAGS, &ifr) == -1)
+		if (ioctl(env->vmd_sock_fd, SIOCSIFFLAGS, &ifr) == -1)
 			log_warn("SIOCSIFFLAGS");
 		break;
 	case IMSG_VMDOP_PRIV_IFGROUP:
@@ -179,7 +179,7 @@ priv_dispatch_parent(int fd, struct privsep_proc *p, s
 		    sizeof(ifgr.ifgr_group)) >= sizeof(ifgr.ifgr_group))
 			fatalx("%s: group name too long", __func__);

-		if (ioctl(env->vmd_fd, SIOCAIFGROUP, &ifgr) == -1 &&
+		if (ioctl(env->vmd_sock_fd, SIOCAIFGROUP, &ifgr) == -1 &&
 		    errno != EEXIST)
 			log_warn("SIOCAIFGROUP");
 		break;
@@ -198,7 +198,7 @@ priv_dispatch_parent(int fd, struct privsep_proc *p, s
 		memcpy(&ifra.ifra_mask, &vfr.vfr_mask,
 		    sizeof(ifra.ifra_mask));

-		if (ioctl(env->vmd_fd, SIOCAIFADDR, &ifra) == -1)
+		if (ioctl(env->vmd_sock_fd, SIOCAIFADDR, &ifra) == -1)
 			log_warn("SIOCAIFADDR");
 		break;
 	case IMSG_VMDOP_PRIV_IFADDR6:
@@ -221,11 +221,11 @@ priv_dispatch_parent(int fd, struct privsep_proc *p, s
 		in6_ifra.ifra_lifetime.ia6t_vltime = ND6_INFINITE_LIFETIME;
 		in6_ifra.ifra_lifetime.ia6t_pltime = ND6_INFINITE_LIFETIME;

-		if (ioctl(env->vmd_fd6, SIOCDIFADDR_IN6, &in6_ifra) == -1 &&
+		if (ioctl(env->vmd_sock_fd6, SIOCDIFADDR_IN6, &in6_ifra) == -1 &&
 		    errno != EADDRNOTAVAIL)
 			log_warn("SIOCDIFADDR_IN6");

-		if (ioctl(env->vmd_fd6, SIOCAIFADDR_IN6, &in6_ifra) == -1)
+		if (ioctl(env->vmd_sock_fd6, SIOCAIFADDR_IN6, &in6_ifra) == -1)
 			log_warn("SIOCAIFADDR_IN6");
 		break;
 	case IMSG_VMDOP_PRIV_GET_ADDR:
blob - 75f783d8fa8aeadc181a952c091ee2d6d7de85d1
blob + d10040759267eb24bfb991643fef02be88b0a5a8
--- usr.sbin/vmd/virtio.c
+++ usr.sbin/vmd/virtio.c
@@ -1657,7 +1657,7 @@ virtio_dev_launch(struct vmd_vm *vm, struct virtio_dev
 		memset(num, 0, sizeof(num));
 		snprintf(num, sizeof(num), "%d", sync_fds[1]);
 		memset(vmm_fd, 0, sizeof(vmm_fd));
-		snprintf(vmm_fd, sizeof(vmm_fd), "%d", env->vmd_fd);
+		snprintf(vmm_fd, sizeof(vmm_fd), "%d", env->vmd_vmm_fd);
 		memset(vm_name, 0, sizeof(vm_name));
 		snprintf(vm_name, sizeof(vm_name), "%s",
 		    vm->vm_params.vmc_name);
blob - e2a7451dfa63ea8c8b512766e48acbcb2533e4be
blob + 66b6e2f705591cb9a43d9a82d563132ad1a57924
--- usr.sbin/vmd/vm.c
+++ usr.sbin/vmd/vm.c
@@ -89,7 +89,7 @@ vm_main(int fd, int fd_vmm)
 	/*
 	 * The vm process relies on global state. Set the fd for /dev/vmm.
 	 */
-	env->vmd_fd = fd_vmm;
+	env->vmd_vmm_fd = fd_vmm;

 	/*
 	 * We aren't root, so we can't chroot(2). Use unveil(2) instead.
@@ -507,7 +507,7 @@ vcpu_reset(uint32_t vmid, uint32_t vcpu_id, struct vcp

 	log_debug("%s: resetting vcpu %d for vm %d", __func__, vcpu_id, vmid);

-	if (ioctl(env->vmd_fd, VMM_IOC_RESETCPU, &vrp) == -1)
+	if (ioctl(env->vmd_vmm_fd, VMM_IOC_RESETCPU, &vrp) == -1)
 		return (errno);

 	return (0);
@@ -557,7 +557,7 @@ vmm_create_vm(struct vmd_vm *vm)
 	vcp.vcp_sev = vmc->vmc_sev;
 	vcp.vcp_seves = vmc->vmc_seves;

-	if (ioctl(env->vmd_fd, VMM_IOC_CREATE, &vcp) == -1)
+	if (ioctl(env->vmd_vmm_fd, VMM_IOC_CREATE, &vcp) == -1)
 		return (errno);

 	vm->vm_vmmid = vcp.vcp_id;
@@ -894,7 +894,7 @@ vcpu_run_loop(void *arg)
 		/* Still more interrupts pending? */
 		vrp->vrp_intr_pending = intr_pending(current_vm);

-		if (ioctl(env->vmd_fd, VMM_IOC_RUN, vrp) == -1) {
+		if (ioctl(env->vmd_vmm_fd, VMM_IOC_RUN, vrp) == -1) {
 			/* If run ioctl failed, exit */
 			ret = errno;
 			log_warn("%s: vm %d / vcpu %d run ioctl failed",
@@ -941,7 +941,7 @@ vcpu_intr(uint32_t vmm_id, uint32_t vcpu_id, uint8_t i
 	vip.vip_vcpu_id = vcpu_id; /* XXX always 0? */
 	vip.vip_intr = intr;

-	if (ioctl(env->vmd_fd, VMM_IOC_INTR, &vip) == -1)
+	if (ioctl(env->vmd_vmm_fd, VMM_IOC_INTR, &vip) == -1)
 		return (errno);

 	return (0);
blob - 0a28c186bf2d0c9905123fe5d1f2701cbc287c77
blob + dd4720fad2ac58c09a34d105ef3b3cd58bc49de7
--- usr.sbin/vmd/vmd.c
+++ usr.sbin/vmd/vmd.c
@@ -549,9 +549,13 @@ main(int argc, char **argv)

 	if ((env = calloc(1, sizeof(*env))) == NULL)
 		fatal("calloc: env");
-	env->vmd_fd = -1;
-	env->vmd_fd6 = -1;

+	env->vmd_ptm_fd = -1;
+	env->vmd_psp_fd = -1;
+	env->vmd_sock_fd = -1;
+	env->vmd_sock_fd6 = -1;
+	env->vmd_vmm_fd = -1;
+
 	while ((ch = getopt(argc, argv, "D:P:V:X:df:i:j:nt:vp:")) != -1) {
 		switch (ch) {
 		case 'D':
@@ -680,8 +684,8 @@ main(int argc, char **argv)

 	/* Open /dev/vmm early. */
 	if (env->vmd_noaction == 0 && proc_id == PROC_PARENT) {
-		env->vmd_fd = open(VMM_NODE, O_RDWR | O_CLOEXEC);
-		if (env->vmd_fd == -1)
+		env->vmd_vmm_fd = open(VMM_NODE, O_RDWR | O_CLOEXEC);
+		if (env->vmd_vmm_fd == -1)
 			fatal("%s", VMM_NODE);
 	}

@@ -785,7 +789,7 @@ vmd_configure(void)
 	    " chown fattr flock", NULL) == -1)
 		fatal("pledge");

-	if ((env->vmd_ptmfd = getptmfd()) == -1)
+	if ((env->vmd_ptm_fd = getptmfd()) == -1)
 		fatal("getptmfd %s", PATH_PTMDEV);

 	if (parse_config(env->vmd_conffile) == -1) {
@@ -801,7 +805,7 @@ vmd_configure(void)

 	/* Send VMM device fd to vmm proc. */
 	proc_compose_imsg(&env->vmd_ps, PROC_VMM,
-	    IMSG_VMDOP_RECEIVE_VMM_FD, -1, env->vmd_fd, NULL, 0);
+	    IMSG_VMDOP_RECEIVE_VMM_FD, -1, env->vmd_vmm_fd, NULL, 0);

 	/* Send PSP device fd to vmm proc. */
 	if (env->vmd_psp_fd != -1) {
@@ -1607,7 +1611,7 @@ vm_opentty(struct vmd_vm *vm)
 	/*
 	 * Open tty with pre-opened PTM fd
 	 */
-	if (fdopenpty(env->vmd_ptmfd, &vm->vm_tty, &tty_slave, vm->vm_ttyname,
+	if (fdopenpty(env->vmd_ptm_fd, &vm->vm_tty, &tty_slave, vm->vm_ttyname,
 	    NULL, NULL) == -1) {
 		log_warn("fdopenpty");
 		return (-1);
blob - eced284a8b6f93751acd606272cb09deaa47df37
blob + 2dadede5d6e20b59ed8141fe67c12368cfd75ebd
--- usr.sbin/vmd/vmd.h
+++ usr.sbin/vmd/vmd.h
@@ -408,10 +408,11 @@ struct vmd {
 	uint32_t		 vmd_nswitches;
 	struct switchlist	*vmd_switches;

-	int			 vmd_fd;
-	int			 vmd_fd6;
-	int			 vmd_ptmfd;
+	int			 vmd_ptm_fd;
 	int			 vmd_psp_fd;
+	int			 vmd_sock_fd;
+	int			 vmd_sock_fd6;
+	int			 vmd_vmm_fd;
 };

 struct vm_dev_pipe {
blob - ebf5a5c5f6dbb41cb03f967119451be32b624396
blob + 06bd649662ea0d9af4953b13d6fe6370c3cc31f9
--- usr.sbin/vmd/vmm.c
+++ usr.sbin/vmd/vmm.c
@@ -271,15 +271,15 @@ vmm_dispatch_parent(int fd, struct privsep_proc *p, st
 		    imsg_get_fd(imsg), &var, sizeof(var));
 		break;
 	case IMSG_VMDOP_RECEIVE_VMM_FD:
-		if (env->vmd_fd > -1)
+		if (env->vmd_vmm_fd != -1)
 			fatalx("already received vmm fd");
-		env->vmd_fd = imsg_get_fd(imsg);
+		env->vmd_vmm_fd = imsg_get_fd(imsg);

 		/* Get and terminate all running VMs */
 		get_info_vm(ps, NULL, 1);
 		break;
 	case IMSG_VMDOP_RECEIVE_PSP_FD:
-		if (env->vmd_psp_fd > -1)
+		if (env->vmd_psp_fd != -1)
 			fatalx("already received psp fd");
 		env->vmd_psp_fd = imsg_get_fd(imsg);
 		break;
@@ -530,7 +530,7 @@ vmm_dispatch_vm(int fd, short event, void *arg)
 int
 terminate_vm(struct vm_terminate_params *vtp)
 {
-	if (ioctl(env->vmd_fd, VMM_IOC_TERM, vtp) == -1)
+	if (ioctl(env->vmd_vmm_fd, VMM_IOC_TERM, vtp) == -1)
 		return (errno);

 	return (0);
@@ -734,7 +734,7 @@ vmm_start_vm(struct imsg *imsg, uint32_t *id, pid_t *p
 		memset(num, 0, sizeof(num));
 		snprintf(num, sizeof(num), "%d", fds[1]);
 		memset(vmm_fd, 0, sizeof(vmm_fd));
-		snprintf(vmm_fd, sizeof(vmm_fd), "%d", env->vmd_fd);
+		snprintf(vmm_fd, sizeof(vmm_fd), "%d", env->vmd_vmm_fd);
 		memset(psp_fd, 0, sizeof(psp_fd));
 		snprintf(psp_fd, sizeof(psp_fd), "%d", env->vmd_psp_fd);

@@ -817,7 +817,7 @@ get_info_vm(struct privsep *ps, struct imsg *imsg, int
 	memset(&vir, 0, sizeof(vir));

 	/* First ioctl to see how many bytes needed (vip.vip_size) */
-	if (ioctl(env->vmd_fd, VMM_IOC_INFO, &vip) == -1)
+	if (ioctl(env->vmd_vmm_fd, VMM_IOC_INFO, &vip) == -1)
 		return (errno);

 	if (vip.vip_info_ct != 0)
@@ -829,7 +829,7 @@ get_info_vm(struct privsep *ps, struct imsg *imsg, int

 	/* Second ioctl to get the actual list */
 	vip.vip_info = info;
-	if (ioctl(env->vmd_fd, VMM_IOC_INFO, &vip) == -1) {
+	if (ioctl(env->vmd_vmm_fd, VMM_IOC_INFO, &vip) == -1) {
 		ret = errno;
 		free(info);
 		return (ret);