usr.sbin/pwm/pwm.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
   3  *
   4  * Copyright (c) 2018 Emmanuel Vadot <manu@FreeBSD.org>
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  *
  28  * $FreeBSD$
  29  */
  30
  31 #include <sys/types.h>
  32 #include <sys/ioctl.h>
  33 #include <stdbool.h>
  34 #include <sys/capsicum.h>
  35 #include <dev/pwm/pwmc.h>
  36
  37 #include <err.h>
  38 #include <errno.h>
  39 #include <fcntl.h>
  40 #include <limits.h>
  41 #include <stdio.h>
  42 #include <stdlib.h>
  43 #include <string.h>
  44 #include <unistd.h>
  45 #include <capsicum_helpers.h>
  46
  47 #define PWM_ENABLE      0x0001
  48 #define PWM_DISABLE     0x0002
  49 #define PWM_SHOW_CONFIG 0x0004
  50 #define PWM_PERIOD      0x0008
  51 #define PWM_DUTY        0x0010
  52
  53 static char device_name[PATH_MAX] = "/dev/pwm/pwmc0.0";
  54
  55 static void
  56 set_device_name(const char *name)
  57 {
  58
  59         if (name[0] == '/')
  60                 strlcpy(device_name, name, sizeof(device_name));
  61         else
  62                 snprintf(device_name, sizeof(device_name), "/dev/pwm/%s", name);
  63 }
  64
  65 static void
  66 usage(void)
  67 {
  68         fprintf(stderr, "Usage:\n");
  69         fprintf(stderr, "\tpwm [-f dev] -C\n");
  70         fprintf(stderr, "\tpwm [-f dev] [-D | -E] [-p period] [-d duty[%%]]\n");
  71         exit(1);
  72 }
  73
  74 int
  75 main(int argc, char *argv[])
  76 {
  77         struct pwm_state state;
  78         int fd;
  79         int period, duty;
  80         int action, ch;
  81         cap_rights_t right_ioctl;
  82         const unsigned long pwm_ioctls[] = {PWMGETSTATE, PWMSETSTATE};
  83         char *percent;
  84         bool setname;
  85
  86         action = 0;
  87         setname = false;
  88         fd = -1;
  89         period = duty = -1;
  90
  91         while ((ch = getopt(argc, argv, "f:EDCp:d:")) != -1) {
  92                 switch (ch) {
  93                 case 'E':
  94                         if (action & (PWM_DISABLE | PWM_SHOW_CONFIG))
  95                                 usage();
  96                         action |= PWM_ENABLE;
  97                         break;
  98                 case 'D':
  99                         if (action & (PWM_ENABLE | PWM_SHOW_CONFIG))
 100                                 usage();
 101                         action |= PWM_DISABLE;
 102                         break;
 103                 case 'C':
 104                         if (action)
 105                                 usage();
 106                         action = PWM_SHOW_CONFIG;
 107                         break;
 108                 case 'p':
 109                         if (action & PWM_SHOW_CONFIG)
 110                                 usage();
 111                         action |= PWM_PERIOD;
 112                         period = strtol(optarg, NULL, 10);
 113                         break;
 114                 case 'd':
 115                         if (action & PWM_SHOW_CONFIG)
 116                                 usage();
 117                         action |= PWM_DUTY;
 118                         duty = strtol(optarg, &percent, 10);
 119                         if (*percent == '%') {
 120                                 if (duty < 0 || duty > 100) {
 121                                         fprintf(stderr,
 122                                             "Invalid duty percentage\n");
 123                                         usage();
 124                                 }
 125                         } else if (*percent != '\0')
 126                                 usage();
 127                         break;
 128                 case 'f':
 129                         setname = true;
 130                         set_device_name(optarg);
 131                         break;
 132                 case '?':
 133                         usage();
 134                         break;
 135                 }
 136         }
 137
 138         if (action == 0)
 139                 usage();
 140
 141         if ((fd = open(device_name, O_RDWR)) == -1) {
 142                 fprintf(stderr, "pwm: cannot open %s: %s\n",
 143                     device_name, strerror(errno));
 144                 if (setname)
 145                         exit(1);
 146                 else
 147                         usage();
 148         }
 149
 150         if (caph_limit_stdio() < 0) {
 151                 fprintf(stderr, "can't limit stdio rights");
 152                 goto fail;
 153         }
 154         caph_cache_catpages();
 155         cap_rights_init(&right_ioctl, CAP_IOCTL);
 156         if (caph_rights_limit(fd, &right_ioctl) < 0) {
 157                 fprintf(stderr, "cap_right_limit() failed\n");
 158                 goto fail;
 159         }
 160         if (caph_ioctls_limit(fd, pwm_ioctls, nitems(pwm_ioctls)) < 0) {
 161                 fprintf(stderr, "caph_ioctls_limit() failed\n");
 162                 goto fail;
 163         }
 164         if (caph_enter() < 0) {
 165                 fprintf(stderr, "failed to enter capability mode\n");
 166                 goto fail;
 167         }
 168
 169         /* Fill the common args */
 170         if (ioctl(fd, PWMGETSTATE, &state) == -1) {
 171                 fprintf(stderr, "Cannot get current state of the pwm controller\n");
 172                 goto fail;
 173         }
 174
 175         if (action == PWM_SHOW_CONFIG) {
 176                 printf("period: %u\nduty: %u\nenabled:%d\n",
 177                     state.period,
 178                     state.duty,
 179                     state.enable);
 180                 goto fail;
 181         } else {
 182                 if (action & PWM_ENABLE)
 183                         state.enable = true;
 184                 if (action & PWM_DISABLE)
 185                         state.enable = false;
 186                 if (action & PWM_PERIOD)
 187                         state.period = period;
 188                 if (action & PWM_DUTY) {
 189                         if (*percent != '\0')
 190                                 state.duty = state.period * duty / 100;
 191                         else
 192                                 state.duty = duty;
 193                 }
 194
 195                 if (ioctl(fd, PWMSETSTATE, &state) == -1) {
 196                         fprintf(stderr,
 197                           "Cannot configure the pwm controller\n");
 198                         goto fail;
 199                 }
 200         }
 201
 202         close(fd);
 203         return (0);
 204
 205 fail:
 206         close(fd);
 207         return (1);
 208 }