Allow non-privilaged user to retrive battery or AC line information.

Reviewed by: rwatson

sys/dev/acpica/acpi.c

@@ -33,6 +33,7 @@
 #include <sys/param.h>
 #include <sys/kernel.h>
 #include <sys/proc.h>
+#include <sys/fcntl.h>
 #include <sys/malloc.h>
 #include <sys/bus.h>
 #include <sys/conf.h>
@@ -487,7 +488,7 @@ acpi_attach(device_t dev)
     /*
      * Create the control device
      */
-    sc->acpi_dev_t = make_dev(&acpi_cdevsw, 0, UID_ROOT, GID_WHEEL, 0600,
+    sc->acpi_dev_t = make_dev(&acpi_cdevsw, 0, UID_ROOT, GID_WHEEL, 0644,
 	"acpi");
     sc->acpi_dev_t->si_drv1 = sc;
 
@@ -1843,6 +1844,15 @@ acpiioctl(dev_t dev, u_long cmd, caddr_t addr, int flag, d_thread_t *td)
 	}
     }
 
+    /*
+     * Core ioctls are  not permitted for non-writable user.
+     * Currently, other ioctls just fetch information.
+     * Not changing system behavior.
+     */
+    if(!(flag & FWRITE)){
+	    return EPERM;
+    }
+
     /*
      * Core system ioctls.
      */

sys/dev/acpica/acpi_acad.c

@@ -195,6 +195,11 @@ acpi_acad_ioctl(u_long cmd, caddr_t addr, void *arg)
 		return(ENXIO);
 	}
 
+        /*
+         * No security check required: information retrieval only.  If
+         * new functions are added here, a check might be required.
+         */
+
 	switch (cmd) {
 	case ACPIIO_ACAD_GET_STATUS:
 		acpi_acad_get_status(dev);

sys/dev/acpica/acpi_battery.c

@@ -138,6 +138,12 @@ acpi_battery_ioctl(u_long cmd, caddr_t addr, void *arg)
 
 	ioctl_arg = (union acpi_battery_ioctl_arg *)addr;
 	error = 0;
+
+	/*
+         * No security check required: information retrieval only.  If
+         * new functions are added here, a check might be required.
+         */
+
 	switch (cmd) {
 	case ACPIIO_BATT_GET_UNITS:
 		*(int *)addr = acpi_battery_get_units();

sys/dev/acpica/acpi_cmbat.c

@@ -405,6 +405,11 @@ acpi_cmbat_ioctl(u_long cmd, caddr_t addr, void *arg)
 		return (ENXIO);
 	}
 
+        /*
+         * No security check required: information retrieval only.  If
+         * new functions are added here, a check might be required.
+         */
+	
 	switch (cmd) {
 	case ACPIIO_CMBAT_GET_BIF:
 		acpi_cmbat_get_bif(dev);