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] -E\n");
  70         fprintf(stderr, "\tpwm [-f dev] -D\n");
  71         fprintf(stderr, "\tpwm [-f dev] -C\n");
  72         fprintf(stderr, "\tpwm [-f dev] -p period\n");
  73         fprintf(stderr, "\tpwm [-f dev] -d duty\n");
  74         exit(1);
  75 }
  76
  77 int
  78 main(int argc, char *argv[])
  79 {
  80         struct pwm_state state;
  81         int fd;
  82         int period, duty;
  83         int action, ch;
  84         cap_rights_t right_ioctl;
  85         const unsigned long pwm_ioctls[] = {PWMGETSTATE, PWMSETSTATE};
  86         char *percent;
  87         bool setname;
  88
  89         action = 0;
  90         setname = false;
  91         fd = -1;
  92         period = duty = -1;
  93
  94         while ((ch = getopt(argc, argv, "f:EDCp:d:")) != -1) {
  95                 switch (ch) {
  96                 case 'E':
  97                         if (action)
  98                                 usage();
  99                         action = PWM_ENABLE;
 100                         break;
 101                 case 'D':
 102                         if (action)
 103                                 usage();
 104                         action = PWM_DISABLE;
 105                         break;
 106                 case 'C':
 107                         if (action)
 108                                 usage();
 109                         action = PWM_SHOW_CONFIG;
 110                         break;
 111                 case 'p':
 112                         if (action & ~(PWM_PERIOD | PWM_DUTY))
 113                                 usage();
 114                         action = PWM_PERIOD;
 115                         period = strtol(optarg, NULL, 10);
 116                         break;
 117                 case 'd':
 118                         if (action & ~(PWM_PERIOD | PWM_DUTY))
 119                                 usage();
 120                         action = PWM_DUTY;
 121                         duty = strtol(optarg, &percent, 10);
 122                         if (*percent != '\0' && *percent != '%')
 123                                 usage();
 124                         break;
 125                 case 'f':
 126                         setname = true;
 127                         set_device_name(optarg);
 128                         break;
 129                 case '?':
 130                         usage();
 131                         break;
 132                 }
 133         }
 134
 135         if (action == 0)
 136                 usage();
 137
 138         if ((fd = open(device_name, O_RDWR)) == -1) {
 139                 fprintf(stderr, "pwm: cannot open %s: %s\n",
 140                     device_name, strerror(errno));
 141                 if (setname)
 142                         exit(1);
 143                 else
 144                         usage();
 145         }
 146
 147         if (caph_limit_stdio() < 0) {
 148                 fprintf(stderr, "can't limit stdio rights");
 149                 goto fail;
 150         }
 151         caph_cache_catpages();
 152         cap_rights_init(&right_ioctl, CAP_IOCTL);
 153         if (caph_rights_limit(fd, &right_ioctl) < 0) {
 154                 fprintf(stderr, "cap_right_limit() failed\n");
 155                 goto fail;
 156         }
 157         if (caph_ioctls_limit(fd, pwm_ioctls, nitems(pwm_ioctls)) < 0) {
 158                 fprintf(stderr, "caph_ioctls_limit() failed\n");
 159                 goto fail;
 160         }
 161         if (caph_enter() < 0) {
 162                 fprintf(stderr, "failed to enter capability mode\n");
 163                 goto fail;
 164         }
 165
 166         /* Fill the common args */
 167         if (ioctl(fd, PWMGETSTATE, &state) == -1) {
 168                 fprintf(stderr, "Cannot get current state of the pwm controller\n");
 169                 goto fail;
 170         }
 171
 172         switch (action) {
 173         case PWM_ENABLE:
 174                 if (state.enable == false) {
 175                         state.enable = true;
 176                         if (ioctl(fd, PWMSETSTATE, &state) == -1) {
 177                                 fprintf(stderr,
 178                                     "Cannot enable the pwm controller\n");
 179                                 goto fail;
 180                         }
 181                 }
 182                 break;
 183         case PWM_DISABLE:
 184                 if (state.enable == true) {
 185                         state.enable = false;
 186                         if (ioctl(fd, PWMSETSTATE, &state) == -1) {
 187                                 fprintf(stderr,
 188                                     "Cannot disable the pwm controller\n");
 189                                 goto fail;
 190                         }
 191                 }
 192                 break;
 193         case PWM_SHOW_CONFIG:
 194                 printf("period: %u\nduty: %u\nenabled:%d\n",
 195                     state.period,
 196                     state.duty,
 197                     state.enable);
 198                 break;
 199         case PWM_PERIOD:
 200         case PWM_DUTY:
 201                 if (period != -1)
 202                         state.period = period;
 203                 if (duty != -1) {
 204                         if (*percent != '\0')
 205                                 state.duty = state.period * duty / 100;
 206                         else
 207                                 state.duty = duty;
 208                 }
 209                 if (ioctl(fd, PWMSETSTATE, &state) == -1) {
 210                         fprintf(stderr,
 211                           "Cannot configure the pwm controller\n");
 212                         goto fail;
 213                 }
 214                 break;
 215         }
 216
 217         close(fd);
 218         return (0);
 219
 220 fail:
 221         close(fd);
 222         return (1);
 223 }