slstatus.c

   1 /* See LICENSE file for copyright and license details. */
   2 #include <errno.h>
   3 #include <signal.h>
   4 #include <stdio.h>
   5 #include <stdlib.h>
   6 #include <string.h>
   7 #include <time.h>
   8 #include <X11/Xlib.h>
   9
  10 #include "arg.h"
  11 #include "slstatus.h"
  12 #include "util.h"
  13
  14 struct arg {
  15         const char *(*func)();
  16         const char *fmt;
  17         const char *args;
  18 };
  19
  20 char *argv0;
  21 char buf[1024];
  22 static int done;
  23 static Display *dpy;
  24
  25 #include "config.h"
  26
  27 static void
  28 terminate(const int signo)
  29 {
  30         (void)signo;
  31
  32         done = 1;
  33 }
  34
  35 static void
  36 difftimespec(struct timespec *res, struct timespec *a, struct timespec *b)
  37 {
  38         res->tv_sec = a->tv_sec - b->tv_sec - (a->tv_nsec < b->tv_nsec);
  39         res->tv_nsec = a->tv_nsec - b->tv_nsec +
  40                        (a->tv_nsec < b->tv_nsec) * 1000000000;
  41 }
  42
  43 static void
  44 usage(void)
  45 {
  46         fprintf(stderr, "usage: %s [-s]\n", argv0);
  47         exit(1);
  48 }
  49
  50 int
  51 main(int argc, char *argv[])
  52 {
  53         struct sigaction act;
  54         struct timespec start, current, diff, intspec, wait;
  55         size_t i, len;
  56         int sflag, ret;
  57         char status[MAXLEN];
  58         const char *res;
  59
  60         sflag = 0;
  61         ARGBEGIN {
  62                 case 's':
  63                         sflag = 1;
  64                         break;
  65                 default:
  66                         usage();
  67         } ARGEND
  68
  69         if (argc) {
  70                 usage();
  71         }
  72
  73         memset(&act, 0, sizeof(act));
  74         act.sa_handler = terminate;
  75         sigaction(SIGINT,  &act, NULL);
  76         sigaction(SIGTERM, &act, NULL);
  77
  78         if (sflag) {
  79                 setbuf(stdout, NULL);
  80         }
  81
  82         if (!sflag && !(dpy = XOpenDisplay(NULL))) {
  83                 fprintf(stderr, "XOpenDisplay: Failed to open display\n");
  84                 return 1;
  85         }
  86
  87         while (!done) {
  88                 if (clock_gettime(CLOCK_MONOTONIC, &start) < 0) {
  89                         fprintf(stderr, "clock_gettime: %s\n", strerror(errno));
  90                         return 1;
  91                 }
  92
  93                 status[0] = '\0';
  94                 for (i = len = 0; i < LEN(args); i++) {
  95                         if (!(res = args[i].func(args[i].args))) {
  96                                 res = unknown_str;
  97                         }
  98                         if ((ret = snprintf(status + len, sizeof(status) - len,
  99                                             args[i].fmt, res)) < 0) {
 100                                 fprintf(stderr, "snprintf: %s\n",
 101                                         strerror(errno));
 102                                 break;
 103                         } else if ((size_t)ret >= sizeof(status) - len) {
 104                                 fprintf(stderr, "snprintf: Output truncated\n");
 105                                 break;
 106                         }
 107                         len += ret;
 108                 }
 109
 110                 if (sflag) {
 111                         printf("%s\n", status);
 112                 } else {
 113                         if (XStoreName(dpy, DefaultRootWindow(dpy), status) < 0) {
 114                                 fprintf(stderr,
 115                                         "XStoreName: Allocation failed\n");
 116                                 return 1;
 117                         }
 118                         XFlush(dpy);
 119                 }
 120
 121                 if (!done) {
 122                         if (clock_gettime(CLOCK_MONOTONIC, &current) < 0) {
 123                                 fprintf(stderr, "clock_gettime: %s\n",
 124                                         strerror(errno));
 125                                 return 1;
 126                         }
 127                         difftimespec(&diff, &current, &start);
 128
 129                         intspec.tv_sec = interval / 1000;
 130                         intspec.tv_nsec = (interval % 1000) * 1000000;
 131                         difftimespec(&wait, &intspec, &diff);
 132
 133                         if (wait.tv_sec >= 0) {
 134                                 if (nanosleep(&wait, NULL) < 0 &&
 135                                     errno != EINTR) {
 136                                         fprintf(stderr, "nanosleep: %s\n",
 137                                                 strerror(errno));
 138                                         return 1;
 139                                 }
 140                         }
 141                 }
 142         }
 143
 144         if (!sflag) {
 145                 XStoreName(dpy, DefaultRootWindow(dpy), NULL);
 146                 if (XCloseDisplay(dpy) < 0) {
 147                         fprintf(stderr,
 148                                 "XCloseDisplay: Failed to close display\n");
 149                         return 1;
 150                 }
 151         }
 152
 153         return 0;
 154 }