Replace openpty(3) with local function that uses pre-opened /dev/ptm fd

This allows more flexibility for upcoming changes and better pledge.
We also didn't use half of the features of libutil's openpty function.
Additionally, make sure that the ttys are closed correctly on shutdown.

OK gilles@

3 files changed, 58 insertions, 21 deletions

diff --git a/usr.sbin/vmd/config.c b/usr.sbin/vmd/config.c
index f35a3b3562d..11069b816a6 100644
--- a/usr.sbin/vmd/config.c
+++ b/usr.sbin/vmd/config.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: config.c,v 1.23 2017/01/17 21:51:01 krw Exp $	*/
+/*	$OpenBSD: config.c,v 1.24 2017/02/27 14:37:58 reyk Exp $	*/
 
 /*
  * Copyright (c) 2015 Reyk Floeter <reyk@openbsd.org>
@@ -126,10 +126,9 @@ config_setvm(struct privsep *ps, struct vmd_vm *vm, uint32_t peerid)
 	struct vmop_create_params *vmc = &vm->vm_params;
 	struct vm_create_params	*vcp = &vmc->vmc_params;
 	unsigned int		 i;
-	int			 fd = -1, ttys_fd;
+	int			 fd = -1;
 	int			 kernfd = -1, *diskfds = NULL, *tapfds = NULL;
 	int			 saved_errno = 0;
-	char			 ptyname[VM_TTYNAME_MAX];
 	char			 ifname[IF_NAMESIZE], *s;
 	char			 path[PATH_MAX];
 	unsigned int		 unit;
@@ -241,12 +240,11 @@ config_setvm(struct privsep *ps, struct vmd_vm *vm, uint32_t peerid)
 
 	/* Open TTY */
 	if (vm->vm_ttyname == NULL) {
-		if (openpty(&vm->vm_tty, &ttys_fd, ptyname, NULL, NULL) == -1 ||
-		    (vm->vm_ttyname = strdup(ptyname)) == NULL) {
-			log_warn("%s: can't open tty %s", __func__, ptyname);
+		if (vm_opentty(vm) == -1) {
+			log_warn("%s: can't open tty %s", __func__,
+			    vm->vm_ttyname == NULL ? "" : vm->vm_ttyname);
 			goto fail;
 		}
-		close(ttys_fd);
 	}
 	if ((fd = dup(vm->vm_tty)) == -1) {
 		log_warn("%s: can't re-open tty %s", __func__, vm->vm_ttyname);
diff --git a/usr.sbin/vmd/vmd.c b/usr.sbin/vmd/vmd.c
index a01e40f2b13..3ae6b1b2ffa 100644
--- a/usr.sbin/vmd/vmd.c
+++ b/usr.sbin/vmd/vmd.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: vmd.c,v 1.50 2017/01/13 19:21:16 edd Exp $	*/
+/*	$OpenBSD: vmd.c,v 1.51 2017/02/27 14:37:58 reyk Exp $	*/
 
 /*
  * Copyright (c) 2015 Reyk Floeter <reyk@openbsd.org>
@@ -20,6 +20,8 @@
 #include <sys/queue.h>
 #include <sys/wait.h>
 #include <sys/cdefs.h>
+#include <sys/tty.h>
+#include <sys/ioctl.h>
 
 #include <stdio.h>
 #include <stdlib.h>
@@ -33,7 +35,6 @@
 #include <syslog.h>
 #include <unistd.h>
 #include <ctype.h>
-#include <util.h>
 
 #include "proc.h"
 #include "vmd.h"
@@ -484,6 +485,9 @@ vmd_configure(void)
 	struct vmd_vm		*vm;
 	struct vmd_switch	*vsw;
 
+	if ((env->vmd_ptmfd = open(PATH_PTMDEV, O_RDWR|O_CLOEXEC)) == -1)
+		fatal("open %s", PATH_PTMDEV);
+
 	/*
 	 * pledge in the parent process:
 	 * stdio - for malloc and basic I/O including events.
@@ -605,6 +609,12 @@ vmd_reload(unsigned int reset, const char *filename)
 void
 vmd_shutdown(void)
 {
+	struct vmd_vm *vm, *vm_next;
+
+	TAILQ_FOREACH_SAFE(vm, env->vmd_vms, vm_entry, vm_next) {
+		vm_remove(vm);
+	}
+
 	proc_kill(&env->vmd_ps);
 	free(env);
 
@@ -702,16 +712,8 @@ vm_stop(struct vmd_vm *vm, int keeptty)
 		close(vm->vm_kernel);
 		vm->vm_kernel = -1;
 	}
-
-	if (keeptty)
-		return;
-
-	if (vm->vm_tty != -1) {
-		close(vm->vm_tty);
-		vm->vm_tty = -1;
-	}
-	free(vm->vm_ttyname);
-	vm->vm_ttyname = NULL;
+	if (!keeptty)
+		vm_closetty(vm);
 }
 
 void
@@ -769,6 +771,7 @@ vm_register(struct privsep *ps, struct vmop_create_params *vmc,
 
 	memcpy(&vm->vm_params, vmc, sizeof(vm->vm_params));
 	vm->vm_pid = -1;
+	vm->vm_tty = -1;
 
 	for (i = 0; i < vcp->vcp_ndisks; i++)
 		vm->vm_disks[i] = -1;
@@ -787,12 +790,45 @@ vm_register(struct privsep *ps, struct vmop_create_params *vmc,
 
 	*ret_vm = vm;
 	return (0);
-fail:
+ fail:
 	if (errno == 0)
 		errno = EINVAL;
 	return (-1);
 }
 
+int
+vm_opentty(struct vmd_vm *vm)
+{
+	struct ptmget		 ptm;
+
+	/*
+	 * Open tty with pre-opened PTM fd
+	 */
+	if ((ioctl(env->vmd_ptmfd, PTMGET, &ptm) == -1))
+		return (-1);
+
+	vm->vm_tty = ptm.cfd;
+	close(ptm.sfd);
+	if ((vm->vm_ttyname = strdup(ptm.sn)) == NULL)
+		goto fail;
+
+	return (0);
+ fail:
+	vm_closetty(vm);
+	return (-1);
+}
+
+void
+vm_closetty(struct vmd_vm *vm)
+{
+	if (vm->vm_tty != -1) {
+		close(vm->vm_tty);
+		vm->vm_tty = -1;
+	}
+	free(vm->vm_ttyname);
+	vm->vm_ttyname = NULL;
+}
+
 void
 switch_remove(struct vmd_switch *vsw)
 {
diff --git a/usr.sbin/vmd/vmd.h b/usr.sbin/vmd/vmd.h
index e371112feef..b125887f6fb 100644
--- a/usr.sbin/vmd/vmd.h
+++ b/usr.sbin/vmd/vmd.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: vmd.h,v 1.43 2017/01/13 19:21:16 edd Exp $	*/
+/*	$OpenBSD: vmd.h,v 1.44 2017/02/27 14:37:58 reyk Exp $	*/
 
 /*
  * Copyright (c) 2015 Mike Larkin <mlarkin@openbsd.org>
@@ -185,6 +185,7 @@ struct vmd {
 	struct switchlist	*vmd_switches;
 
 	int			 vmd_fd;
+	int			 vmd_ptmfd;
 };
 
 /* vmd.c */
@@ -197,6 +198,8 @@ void	 vm_stop(struct vmd_vm *, int);
 void	 vm_remove(struct vmd_vm *);
 int	 vm_register(struct privsep *, struct vmop_create_params *,
 	    struct vmd_vm **, uint32_t);
+int	 vm_opentty(struct vmd_vm *);
+void	 vm_closetty(struct vmd_vm *);
 void	 switch_remove(struct vmd_switch *);
 struct vmd_switch *switch_getbyname(const char *);
 char	*get_string(uint8_t *, size_t);