Add -A, -a, and -e options to modstat(8) along with kernel

changes required to support these options.  The -e option was
requested by martin@ in private chat in order to make writing tests
easier (i.e. don't bother testing MODULAR functionaility if it
doesn't exist).  While there, I added -A and -a since those were
quite similar.

     -A      Tells you whether or not modules can be autoloaded at the moment.
             This option does take into consideration the sysctl
             kern.module.autoload.

     -a      Tells you whether or not modules can be autoloaded at the moment.
             This option does not take into consideration the sysctl
             kern.module.autoload.

     -e      Tells you whether or not you may load a module at the moment.

doc/CHANGES

@@ -1,4 +1,4 @@
-# LIST OF CHANGES FROM LAST RELEASE:			<$Revision: 1.1729 $>
+# LIST OF CHANGES FROM LAST RELEASE:			<$Revision: 1.1730 $>
 #
 #
 # [Note: This file does not mention every change made to the NetBSD source tree.
@@ -86,7 +86,7 @@ Changes from NetBSD 6.0 to NetBSD 7.0:
 	tdvfb(4): Add 3Dfx Voodoo Graphics (aka Voodoo1) support.
 		[rkujawa 20120720]
 	kernel: Change mii_statchg to take "struct ifnet *" instead of
-		"device_t".  [matt 20120722]
+		"device_t". [matt 20120722]
 	pr(1): Add support for POSIX -f and -p options. [ginsbach 20120724]
 	powerpc: Add support for FPU emulation on BookE. [matt 20120722]
 	zoneinfo: Import tzdata2012d. [apb 20120722]
@@ -94,6 +94,11 @@ Changes from NetBSD 6.0 to NetBSD 7.0:
 	OpenSSL: Imported 1.0.1c [christos 20120726]
 	kernel: safepri is dead; replaced by macro IPL_SAFEPRI. [matt 20120727]
 	kernel: Add malo(4), a driver for Marvell Libertas IEEE 802.11b/g
-		wireless network devices, ported from OpenBSD. [degroote 20120730]
+		wireless network devices, ported from OpenBSD.
+		[degroote 20120730]
 	kernel: Add BPF JIT compiler, currently supporting amd64 and i386.
 		[rmind 20120802]
+	kernel, libc: Add modctl(MODCTL_EXISTS, ...) to determine if modules
+		can be loaded. [jnemeth 20120803]
+	modstat(8): Add -A, -a, and -e options for testing module loadability.
+		[jnemeth 20120803]

lib/libc/sys/modctl.2

@@ -1,4 +1,4 @@
-.\"	$NetBSD: modctl.2,v 1.8 2010/12/14 16:23:59 jruoho Exp $
+.\"	$NetBSD: modctl.2,v 1.9 2012/08/07 01:19:05 jnemeth Exp $
 .\"
 .\" Copyright (c) 2009 The NetBSD Foundation, Inc.
 .\" All rights reserved.
@@ -24,7 +24,7 @@
 .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 .\" POSSIBILITY OF SUCH DAMAGE.
 .\"
-.Dd December 14, 2010
+.Dd August 3, 2012
 .Dt MODCTL 2
 .Os
 .Sh NAME
@@ -44,8 +44,9 @@ The argument
 is one of
 .Dv MODCTL_LOAD ,
 .Dv MODCTL_UNLOAD ,
+.Dv MODCTL_STAT ,
 or
-.Dv MODCTL_STAT .
+.Dv MODCTL_EXISTS .
 The argument
 .Fa argp
 depends on the
@@ -84,6 +85,24 @@ member of the
 .Em iovec
 to reflect the size of the complete report, regardless of whether this
 is larger or smaller than the size passed in.
+.It Dv MODCTL_EXISTS
+Test to see if the kernel was compiled with
+.Dq options MODULAR
+and whether or
+not modules may be loaded at the moment.
+In this case,
+.Fa argp
+should be an integer.
+It should be
+.Dq 0
+to test if a user can load a module via
+.Dv MODCTL_LOAD ,
+or it should be
+.Dq 1
+to test if the system can autoload modules.
+Note that this
+test does not consider the sysctl
+.Li kern.module.autoload .
 .El
 .Ss Data Types
 The
@@ -98,7 +117,8 @@ The name/path of the module to load.
 Zero or more of the following flag values:
 .Bl -tag -compact -width "MODCTL_LOAD_FORCE"
 .It Dv MODCTL_NO_PROP
-Don't load \*[Lt]module\*[Gt].plist.
+Don't load
+.Ao module Ac Ns Pa .plist .
 .It Dv MODCTL_LOAD_FORCE
 Ignore kernel version mismatch.
 .El
@@ -271,6 +291,7 @@ information.
 .El
 .Sh SEE ALSO
 .Xr module 7 ,
+.Xr sysctl 7 ,
 .Xr module 9
 .Sh HISTORY
 The

sbin/modstat/main.c

@@ -1,4 +1,4 @@
-/*	$NetBSD: main.c,v 1.14 2011/08/02 16:46:45 mbalmer Exp $	*/
+/*	$NetBSD: main.c,v 1.15 2012/08/07 01:19:05 jnemeth Exp $	*/
 
 /*-
  * Copyright (c) 2008 The NetBSD Foundation, Inc.
@@ -28,16 +28,19 @@
 
 #include <sys/cdefs.h>
 #ifndef lint
-__RCSID("$NetBSD: main.c,v 1.14 2011/08/02 16:46:45 mbalmer Exp $");
+__RCSID("$NetBSD: main.c,v 1.15 2012/08/07 01:19:05 jnemeth Exp $");
 #endif /* !lint */
 
 #include <sys/module.h>
+#include <sys/param.h>
+#include <sys/sysctl.h>
 
+#include <err.h>
+#include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
-#include <err.h>
 
 #include "prog_ops.h"
 
@@ -70,13 +73,19 @@ main(int argc, char **argv)
 	size_t len;
 	const char *name;
 	char sbuf[32];
-	int ch;
+	int ch, rc, modauto = 1;
-	size_t maxnamelen = 16, i;
+	size_t maxnamelen = 16, i, modautolen;
+	char loadable = '\0';
 
 	name = NULL;
 
-	while ((ch = getopt(argc, argv, "n:")) != -1) {
+	while ((ch = getopt(argc, argv, "Aaen:")) != -1) {
 		switch (ch) {
+		case 'A':			/* FALLTHROUGH */
+		case 'a':			/* FALLTHROUGH */
+		case 'e':
+			loadable = (char)ch;
+			break;
 		case 'n':
 			name = optarg;
 			break;
@@ -96,6 +105,56 @@ main(int argc, char **argv)
 	if (prog_init && prog_init() == -1)
 		err(1, "prog init failed");
 
+	if (loadable == 'A' || loadable == 'a') {
+		if (prog_modctl(MODCTL_EXISTS, (void *)(uintptr_t)1)) {
+			switch (errno) {
+			case ENOSYS:
+				errx(EXIT_FAILURE, "The kernel was compiled "
+				    "without options MODULAR.");
+				break;
+			case EPERM:
+				errx(EXIT_FAILURE, "Modules can not be "
+				    "autoloaded right now.");
+				break;
+			default:
+				err(EXIT_FAILURE, "modctl_exists for autoload");
+				break;
+			}
+		} else {
+			if (loadable == 'A') {
+				modautolen = sizeof(modauto);
+				rc = sysctlbyname("kern.module.autoload",
+				    &modauto, &modautolen, NULL, 0);
+				if (rc != 0) {
+					err(EXIT_FAILURE, "sysctl "
+					    "kern.module.autoload failed.");
+				}
+			}
+			errx(EXIT_SUCCESS, "Modules can be autoloaded%s.",
+			modauto ? "" : ", but kern.module.autoload = 0");
+		}
+	}
+
+	if (loadable == 'e') {
+		if (prog_modctl(MODCTL_EXISTS, (void *)(uintptr_t)0)) {
+			switch (errno) {
+			case ENOSYS:
+				errx(EXIT_FAILURE, "The kernel was compiled "
+				    "without options MODULAR.");
+				break;
+			case EPERM:
+				errx(EXIT_FAILURE, "You are not allowed to "
+				    "load modules right now.");
+				break;
+			default:
+				err(EXIT_FAILURE, "modctl_exists for autoload");
+				break;
+			}
+		} else {
+			errx(EXIT_SUCCESS, "You can load modules.");
+		}
+	}
+
 	for (len = 8192;;) {
 		iov.iov_base = malloc(len);
 		iov.iov_len = len;
@@ -157,7 +216,7 @@ static void
 usage(void)
 {
 
-	(void)fprintf(stderr, "Usage: %s [-n] [name]\n", getprogname());
+	(void)fprintf(stderr, "Usage: %s [-Aaen] [name]\n", getprogname());
 	exit(EXIT_FAILURE);
 }
 

sbin/modstat/modstat.8

@@ -1,4 +1,4 @@
-.\" $NetBSD: modstat.8,v 1.9 2011/08/02 16:46:45 mbalmer Exp $
+.\" $NetBSD: modstat.8,v 1.10 2012/08/07 01:19:05 jnemeth Exp $
 .\"
 .\" Copyright (c) 1993 Christopher G. Demetriou
 .\" All rights reserved.
@@ -32,7 +32,7 @@
 .\"
 .\" <<Id: LICENSE,v 1.2 2000/06/14 15:57:33 cgd Exp>>
 .\"
-.Dd August 2, 2011
+.Dd August 6, 2012
 .Dt MODSTAT 8
 .Os
 .Sh NAME
@@ -40,7 +40,7 @@
 .Nd display status of loaded kernel modules
 .Sh SYNOPSIS
 .Nm
-.Op Fl n
+.Op Fl Aaen
 .Op Ar name
 .Sh DESCRIPTION
 The
@@ -49,6 +49,16 @@ utility displays the status of any kernel modules present in the kernel.
 .Pp
 The options are as follows:
 .Bl -tag -width indent
+.It Fl A
+Tells you whether or not modules can be autoloaded at the moment.
+This option does take into consideration the sysctl
+.Li kern.module.autoload .
+.It Fl a
+Tells you whether or not modules can be autoloaded at the moment.
+This option does not take into consideration the sysctl
+.Li kern.module.autoload .
+.It Fl e
+Tells you whether or not you may load a module at the moment.
 .It Fl n Ar name
 Display the status of only the module with this name.
 Please note that
@@ -88,6 +98,7 @@ utility exits with a status of 0 on success
 and with a nonzero status if an error occurs.
 .Sh SEE ALSO
 .Xr module 7 ,
+.Xr sysctl 7 ,
 .Xr modload 8 ,
 .Xr modunload 8
 .Sh HISTORY

sys/kern/sys_module.c

@@ -1,4 +1,4 @@
-/*	$NetBSD: sys_module.c,v 1.13 2011/07/08 09:32:45 mrg Exp $	*/
+/*	$NetBSD: sys_module.c,v 1.14 2012/08/07 01:19:05 jnemeth Exp $	*/
 
 /*-
  * Copyright (c) 2008 The NetBSD Foundation, Inc.
@@ -31,18 +31,21 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: sys_module.c,v 1.13 2011/07/08 09:32:45 mrg Exp $");
+__KERNEL_RCSID(0, "$NetBSD: sys_module.c,v 1.14 2012/08/07 01:19:05 jnemeth Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/proc.h>
 #include <sys/namei.h>
+#include <sys/kauth.h>
 #include <sys/kmem.h>
 #include <sys/kobj.h>
 #include <sys/module.h>
 #include <sys/syscall.h>
 #include <sys/syscallargs.h>
 
+#include <opt_modular.h>
+
 static int
 handle_modctl_load(modctl_load_t *ml)
 {
@@ -121,6 +124,9 @@ sys_modctl(struct lwp *l, const struct sys_modctl_args *uap,
 	modctl_load_t ml;
 	int error;
 	void *arg;
+#ifdef MODULAR
+	uintptr_t loadtype;
+#endif
 
 	arg = SCARG(uap, arg);
 
@@ -197,6 +203,27 @@ sys_modctl(struct lwp *l, const struct sys_modctl_args *uap,
 		}
 		break;
 
+	case MODCTL_EXISTS:
+#ifndef MODULAR
+		error = ENOSYS;
+#else
+		loadtype = (uintptr_t)arg;
+		switch (loadtype) {	/* 0 = modload, 1 = autoload */
+		case 0:			/* FALLTHROUGH */
+		case 1:
+			error = kauth_authorize_system(kauth_cred_get(),
+			     KAUTH_SYSTEM_MODULE, 0,
+			     (void *)(uintptr_t)MODCTL_LOAD,
+			     (void *)loadtype, NULL);
+			break;
+
+		default:
+			error = EINVAL;
+			break;
+		}
+#endif
+		break;
+
 	default:
 		error = EINVAL;
 		break;

sys/sys/module.h

@@ -1,4 +1,4 @@
-/*	$NetBSD: module.h,v 1.30 2011/11/21 04:36:05 christos Exp $	*/
+/*	$NetBSD: module.h,v 1.31 2012/08/07 01:19:06 jnemeth Exp $	*/
 
 /*-
  * Copyright (c) 2008 The NetBSD Foundation, Inc.
@@ -179,7 +179,8 @@ typedef struct modctl_load {
 typedef enum modctl {
 	MODCTL_LOAD,		/* modctl_load_t *ml */
 	MODCTL_UNLOAD,		/* char *name */
-	MODCTL_STAT		/* struct iovec *buffer */
+	MODCTL_STAT,		/* struct iovec *buffer */
+	MODCTL_EXISTS		/* enum: 0: load, 1: autoload */
 } modctl_t;
 
 /*