diff --git a/toolbox/ioctl.c b/toolbox/ioctl.c
index d1cc14a..093e467 100644
--- a/toolbox/ioctl.c
+++ b/toolbox/ioctl.c
@@ -1,36 +1,81 @@
-#include <stdio.h>
-#include <stdlib.h>
-#include <stdint.h>
+/*
+ * Copyright (c) 2008, The Android Open Source Project
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ *  * Neither the name of Google, Inc. nor the names of its contributors
+ *    may be used to endorse or promote products derived from this
+ *    software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+ * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <errno.h>
+#include <error.h>
 #include <fcntl.h>
 #include <getopt.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <stdlib.h>
 #include <string.h>
-#include <linux/kd.h>
-#include <linux/vt.h>
-#include <errno.h>
-#include <pthread.h>
 #include <sys/ioctl.h>
 #include <unistd.h>
 
-int ioctl_main(int argc, char *argv[])
-{
-    int c;
-    int fd;
-    int res;
+static void usage() {
+    fprintf(stderr, "%s [-l <length>] [-a <argsize>] [-rdh] <device> <ioctlnr>\n"
+            "  -l <length>   Length of io buffer\n"
+            "  -a <argsize>  Size of each argument (1-8)\n"
+            "  -r            Open device in read only mode\n"
+            "  -d            Direct argument (no iobuffer)\n"
+            "  -h            Print help\n", getprogname());
+    exit(1);
+}
 
+static int xstrtoi(const char* s, const char* what) {
+    char* endp;
+    errno = 0;
+    long result = strtol(s, &endp, 0);
+    if (errno != 0 || *endp != '\0') {
+        error(1, errno, "couldn't parse %s '%s'", what, s);
+    }
+    if (result > INT_MAX || result < INT_MIN) {
+        error(1, errno, "%s '%s' out of range", what, s);
+    }
+    return result;
+}
+
+int ioctl_main(int argc, char* argv[]) {
     int read_only = 0;
     int length = -1;
     int arg_size = 4;
     int direct_arg = 0;
-    uint32_t ioctl_nr;
+
     void *ioctl_args = NULL;
     uint8_t *ioctl_argp;
     uint8_t *ioctl_argp_save = NULL;
     int rem;
 
-    do {
-        c = getopt(argc, argv, "rdl:a:h");
-        if (c == EOF)
-            break;
+    int c;
+    while ((c = getopt(argc, argv, "rdl:a:h")) != -1) {
         switch (c) {
         case 'r':
             read_only = 1;
@@ -39,43 +84,44 @@
             direct_arg = 1;
             break;
         case 'l':
-            length = strtol(optarg, NULL, 0);
+            length = xstrtoi(optarg, "length");
             break;
         case 'a':
-            arg_size = strtol(optarg, NULL, 0);
+            arg_size = xstrtoi(optarg, "argument size");
             break;
         case 'h':
-            fprintf(stderr, "%s [-l <length>] [-a <argsize>] [-rdh] <device> <ioctlnr>\n"
-                    "  -l <length>   Length of io buffer\n"
-                    "  -a <argsize>  Size of each argument (1-8)\n"
-                    "  -r            Open device in read only mode\n"
-                    "  -d            Direct argument (no iobuffer)\n"
-                    "  -h            Print help\n", argv[0]);
-            return -1;
-        case '?':
-            fprintf(stderr, "%s: invalid option -%c\n",
-                argv[0], optopt);
-            exit(1);
+            usage();
+            break;
+        default:
+            error(1, 0, "invalid option -%c", optopt);
         }
-    } while (1);
-
-    if(optind + 2 > argc) {
-        fprintf(stderr, "%s: too few arguments\n", argv[0]);
-        exit(1);
     }
 
-    if (!strcmp(argv[optind], "-")) {
+    if (optind + 2 > argc) {
+        usage();
+    }
+
+    const char* device = argv[optind];
+    int fd;
+    if (strcmp(device, "-") == 0) {
         fd = STDIN_FILENO;
     } else {
-        fd = open(argv[optind], read_only ? O_RDONLY : (O_RDWR | O_SYNC));
-        if (fd < 0) {
-            fprintf(stderr, "cannot open %s\n", argv[optind]);
-            return 1;
+        fd = open(device, read_only ? O_RDONLY : (O_RDWR | O_SYNC));
+        if (fd == -1) {
+            error(1, errno, "cannot open %s", argv[optind]);
         }
     }
     optind++;
-    
-    ioctl_nr = strtol(argv[optind], NULL, 0);
+
+    // IOCTL(2) wants second parameter as a signed int.
+    // Let's let the user specify either negative numbers or large positive
+    // numbers, for the case where ioctl number is larger than INT_MAX.
+    errno = 0;
+    char* endp;
+    int ioctl_nr = UINT_MAX & strtoll(argv[optind], &endp, 0);
+    if (errno != 0 || *endp != '\0') {
+        error(1, errno, "couldn't parse ioctl number '%s'", argv[optind]);
+    }
     optind++;
 
     if(direct_arg) {
@@ -91,11 +137,10 @@
 
         ioctl_argp_save = ioctl_argp = ioctl_args;
         rem = length;
-        while(optind < argc) {
+        while (optind < argc) {
             uint64_t tmp = strtoull(argv[optind], NULL, 0);
-            if(rem < arg_size) {
-                fprintf(stderr, "%s: too many arguments\n", argv[0]);
-                exit(1);
+            if (rem < arg_size) {
+                error(1, 0, "too many arguments");
             }
             memcpy(ioctl_argp, &tmp, arg_size);
             ioctl_argp += arg_size;
@@ -108,8 +153,9 @@
     while(rem--) {
         printf(" 0x%02x", *ioctl_argp_save++);
     }
-    printf("\n");
+    printf(" to %s\n", device);
 
+    int res;
     if(direct_arg)
         res = ioctl(fd, ioctl_nr, *(uint32_t*)ioctl_args);
     else if(length)
@@ -118,10 +164,10 @@
         res = ioctl(fd, ioctl_nr, 0);
     if (res < 0) {
         free(ioctl_args);
-        fprintf(stderr, "ioctl 0x%x failed, %d\n", ioctl_nr, res);
-        return 1;
+        error(1, errno, "ioctl 0x%x failed (returned %d)", ioctl_nr, res);
     }
-    if(length) {
+
+    if (length) {
         printf("return buf:");
         ioctl_argp = ioctl_args;
         rem = length;
@@ -131,5 +177,6 @@
         printf("\n");
     }
     free(ioctl_args);
+    close(fd);
     return 0;
 }