usr.sbin/pwm/pwm.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-2-Clause
   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
  28 #include <sys/types.h>
  29 #include <sys/ioctl.h>
  30 #include <stdbool.h>
  31 #include <sys/capsicum.h>
  32 #include <dev/pwm/pwmc.h>
  33
  34 #include <err.h>
  35 #include <errno.h>
  36 #include <fcntl.h>
  37 #include <limits.h>
  38 #include <stdio.h>
  39 #include <stdlib.h>
  40 #include <string.h>
  41 #include <unistd.h>
  42 #include <capsicum_helpers.h>
  43
  44 #define PWM_ENABLE      0x0001
  45 #define PWM_DISABLE     0x0002
  46 #define PWM_SHOW_CONFIG 0x0004
  47 #define PWM_PERIOD      0x0008
  48 #define PWM_DUTY        0x0010
  49 #define PWM_INVERTED    0x0020
  50
  51 static char device_name[PATH_MAX] = "/dev/pwm/pwmc0.0";
  52
  53 static void
  54 set_device_name(const char *name)
  55 {
  56
  57         if (name[0] == '/')
  58                 strlcpy(device_name, name, sizeof(device_name));
  59         else
  60                 snprintf(device_name, sizeof(device_name), "/dev/pwm/%s", name);
  61 }
  62
  63 static void
  64 usage(void)
  65 {
  66         fprintf(stderr, "Usage:\n");
  67         fprintf(stderr, "\tpwm [-f dev] -C\n");
  68         fprintf(stderr, "\tpwm [-f dev] [-D | -E] [-I] [-p period] [-d duty[%%]]\n");
  69         exit(1);
  70 }
  71
  72 int
  73 main(int argc, char *argv[])
  74 {
  75         struct pwm_state state;
  76         int fd;
  77         u_int period, duty;
  78         int action, ch;
  79         cap_rights_t right_ioctl;
  80         const unsigned long pwm_ioctls[] = {PWMGETSTATE, PWMSETSTATE};
  81         char *percent;
  82         bool setname;
  83
  84         action = 0;
  85         setname = false;
  86         fd = -1;
  87         period = duty = -1;
  88
  89         while ((ch = getopt(argc, argv, "f:EDCIp:d:")) != -1) {
  90                 switch (ch) {
  91                 case 'E':
  92                         if (action & (PWM_DISABLE | PWM_SHOW_CONFIG))
  93                                 usage();
  94                         action |= PWM_ENABLE;
  95                         break;
  96                 case 'D':
  97                         if (action & (PWM_ENABLE | PWM_SHOW_CONFIG))
  98                                 usage();
  99                         action |= PWM_DISABLE;
 100                         break;
 101                 case 'C':
 102                         if (action)
 103                                 usage();
 104                         action = PWM_SHOW_CONFIG;
 105                         break;
 106                 case 'I':
 107                         if (action & PWM_SHOW_CONFIG)
 108                                 usage();
 109                         action |= PWM_INVERTED;
 110                         break;
 111                 case 'p':
 112                         if (action & PWM_SHOW_CONFIG)
 113                                 usage();
 114                         action |= PWM_PERIOD;
 115                         period = strtoul(optarg, NULL, 10);
 116                         break;
 117                 case 'd':
 118                         if (action & PWM_SHOW_CONFIG)
 119                                 usage();
 120                         action |= PWM_DUTY;
 121                         duty = strtoul(optarg, &percent, 10);
 122                         if (*percent == '%') {
 123                                 if (duty > 100) {
 124                                         fprintf(stderr,
 125                                             "Invalid duty percentage\n");
 126                                         usage();
 127                                 }
 128                         } else if (*percent != '\0')
 129                                 usage();
 130                         break;
 131                 case 'f':
 132                         setname = true;
 133                         set_device_name(optarg);
 134                         break;
 135                 case '?':
 136                         usage();
 137                         break;
 138                 }
 139         }
 140
 141         if (action == 0)
 142                 usage();
 143
 144         if ((fd = open(device_name, O_RDWR)) == -1) {
 145                 fprintf(stderr, "pwm: cannot open %s: %s\n",
 146                     device_name, strerror(errno));
 147                 if (setname)
 148                         exit(1);
 149                 else
 150                         usage();
 151         }
 152
 153         if (caph_limit_stdio() < 0) {
 154                 fprintf(stderr, "can't limit stdio rights");
 155                 goto fail;
 156         }
 157         caph_cache_catpages();
 158         cap_rights_init(&right_ioctl, CAP_IOCTL);
 159         if (caph_rights_limit(fd, &right_ioctl) < 0) {
 160                 fprintf(stderr, "cap_right_limit() failed\n");
 161                 goto fail;
 162         }
 163         if (caph_ioctls_limit(fd, pwm_ioctls, nitems(pwm_ioctls)) < 0) {
 164                 fprintf(stderr, "caph_ioctls_limit() failed\n");
 165                 goto fail;
 166         }
 167         if (caph_enter() < 0) {
 168                 fprintf(stderr, "failed to enter capability mode\n");
 169                 goto fail;
 170         }
 171
 172         /* Fill the common args */
 173         if (ioctl(fd, PWMGETSTATE, &state) == -1) {
 174                 fprintf(stderr, "Cannot get current state of the pwm controller\n");
 175                 goto fail;
 176         }
 177
 178         if (action == PWM_SHOW_CONFIG) {
 179                 printf("period: %u\nduty: %u\nenabled:%d\ninverted:%d\n",
 180                     state.period,
 181                     state.duty,
 182                     state.enable,
 183                     state.flags & PWM_POLARITY_INVERTED);
 184         } else {
 185                 if (action & PWM_ENABLE)
 186                         state.enable = true;
 187                 if (action & PWM_DISABLE)
 188                         state.enable = false;
 189                 if (action & PWM_PERIOD)
 190                         state.period = period;
 191                 if (action & PWM_INVERTED)
 192                         state.flags |= PWM_POLARITY_INVERTED;
 193                 else
 194                         state.flags &= ~PWM_POLARITY_INVERTED;
 195                 if (action & PWM_DUTY) {
 196                         if (*percent != '\0')
 197                                 state.duty = (uint64_t)state.period * duty / 100;
 198                         else
 199                                 state.duty = duty;
 200                 }
 201
 202                 if (ioctl(fd, PWMSETSTATE, &state) == -1) {
 203                         fprintf(stderr,
 204                           "Cannot configure the pwm controller\n");
 205                         goto fail;
 206                 }
 207         }
 208
 209         close(fd);
 210         return (0);
 211
 212 fail:
 213         close(fd);
 214         return (1);
 215 }