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  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  16  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  17  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  18  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  19  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  20  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  21  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  22  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  23  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  24  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  25  * SUCH DAMAGE.
  26  *
  27  * $FreeBSD$
  28  */
  29
  30 #include <sys/types.h>
  31 #include <sys/ioctl.h>
  32 #include <stdbool.h>
  33 #include <sys/capsicum.h>
  34 #include <dev/pwm/pwmc.h>
  35
  36 #include <err.h>
  37 #include <errno.h>
  38 #include <fcntl.h>
  39 #include <limits.h>
  40 #include <stdio.h>
  41 #include <stdlib.h>
  42 #include <string.h>
  43 #include <unistd.h>
  44 #include <capsicum_helpers.h>
  45
  46 #define PWM_ENABLE      0x0001
  47 #define PWM_DISABLE     0x0002
  48 #define PWM_SHOW_CONFIG 0x0004
  49 #define PWM_PERIOD      0x0008
  50 #define PWM_DUTY        0x0010
  51
  52 static char device_name[PATH_MAX] = "/dev/pwm/pwmc0.0";
  53
  54 static void
  55 set_device_name(const char *name)
  56 {
  57
  58         if (name[0] == '/')
  59                 strlcpy(device_name, name, sizeof(device_name));
  60         else
  61                 snprintf(device_name, sizeof(device_name), "/dev/pwm/%s", name);
  62 }
  63
  64 static void
  65 usage(void)
  66 {
  67         fprintf(stderr, "Usage:\n");
  68         fprintf(stderr, "\tpwm [-f dev] -C\n");
  69         fprintf(stderr, "\tpwm [-f dev] [-D | -E] [-p period] [-d duty[%%]]\n");
  70         exit(1);
  71 }
  72
  73 int
  74 main(int argc, char *argv[])
  75 {
  76         struct pwm_state state;
  77         int fd;
  78         u_int period, duty;
  79         int action, ch;
  80         cap_rights_t right_ioctl;
  81         const unsigned long pwm_ioctls[] = {PWMGETSTATE, PWMSETSTATE};
  82         char *percent;
  83         bool setname;
  84
  85         action = 0;
  86         setname = false;
  87         fd = -1;
  88         period = duty = -1;
  89
  90         while ((ch = getopt(argc, argv, "f:EDCp:d:")) != -1) {
  91                 switch (ch) {
  92                 case 'E':
  93                         if (action & (PWM_DISABLE | PWM_SHOW_CONFIG))
  94                                 usage();
  95                         action |= PWM_ENABLE;
  96                         break;
  97                 case 'D':
  98                         if (action & (PWM_ENABLE | PWM_SHOW_CONFIG))
  99                                 usage();
 100                         action |= PWM_DISABLE;
 101                         break;
 102                 case 'C':
 103                         if (action)
 104                                 usage();
 105                         action = PWM_SHOW_CONFIG;
 106                         break;
 107                 case 'p':
 108                         if (action & PWM_SHOW_CONFIG)
 109                                 usage();
 110                         action |= PWM_PERIOD;
 111                         period = strtoul(optarg, NULL, 10);
 112                         break;
 113                 case 'd':
 114                         if (action & PWM_SHOW_CONFIG)
 115                                 usage();
 116                         action |= PWM_DUTY;
 117                         duty = strtoul(optarg, &percent, 10);
 118                         if (*percent == '%') {
 119                                 if (duty > 100) {
 120                                         fprintf(stderr,
 121                                             "Invalid duty percentage\n");
 122                                         usage();
 123                                 }
 124                         } else if (*percent != '\0')
 125                                 usage();
 126                         break;
 127                 case 'f':
 128                         setname = true;
 129                         set_device_name(optarg);
 130                         break;
 131                 case '?':
 132                         usage();
 133                         break;
 134                 }
 135         }
 136
 137         if (action == 0)
 138                 usage();
 139
 140         if ((fd = open(device_name, O_RDWR)) == -1) {
 141                 fprintf(stderr, "pwm: cannot open %s: %s\n",
 142                     device_name, strerror(errno));
 143                 if (setname)
 144                         exit(1);
 145                 else
 146                         usage();
 147         }
 148
 149         if (caph_limit_stdio() < 0) {
 150                 fprintf(stderr, "can't limit stdio rights");
 151                 goto fail;
 152         }
 153         caph_cache_catpages();
 154         cap_rights_init(&right_ioctl, CAP_IOCTL);
 155         if (caph_rights_limit(fd, &right_ioctl) < 0) {
 156                 fprintf(stderr, "cap_right_limit() failed\n");
 157                 goto fail;
 158         }
 159         if (caph_ioctls_limit(fd, pwm_ioctls, nitems(pwm_ioctls)) < 0) {
 160                 fprintf(stderr, "caph_ioctls_limit() failed\n");
 161                 goto fail;
 162         }
 163         if (caph_enter() < 0) {
 164                 fprintf(stderr, "failed to enter capability mode\n");
 165                 goto fail;
 166         }
 167
 168         /* Fill the common args */
 169         if (ioctl(fd, PWMGETSTATE, &state) == -1) {
 170                 fprintf(stderr, "Cannot get current state of the pwm controller\n");
 171                 goto fail;
 172         }
 173
 174         if (action == PWM_SHOW_CONFIG) {
 175                 printf("period: %u\nduty: %u\nenabled:%d\n",
 176                     state.period,
 177                     state.duty,
 178                     state.enable);
 179         } else {
 180                 if (action & PWM_ENABLE)
 181                         state.enable = true;
 182                 if (action & PWM_DISABLE)
 183                         state.enable = false;
 184                 if (action & PWM_PERIOD)
 185                         state.period = period;
 186                 if (action & PWM_DUTY) {
 187                         if (*percent != '\0')
 188                                 state.duty = (uint64_t)state.period * duty / 100;
 189                         else
 190                                 state.duty = duty;
 191                 }
 192
 193                 if (ioctl(fd, PWMSETSTATE, &state) == -1) {
 194                         fprintf(stderr,
 195                           "Cannot configure the pwm controller\n");
 196                         goto fail;
 197                 }
 198         }
 199
 200         close(fd);
 201         return (0);
 202
 203 fail:
 204         close(fd);
 205         return (1);
 206 }