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 buf[1024];
  21 static int done;
  22 static Display *dpy;
  23
  24 #include "config.h"
  25
  26 static void
  27 terminate(const int signo)
  28 {
  29         (void)signo;
  30
  31         done = 1;
  32 }
  33
  34 static void
  35 difftimespec(struct timespec *res, struct timespec *a, struct timespec *b)
  36 {
  37         res->tv_sec = a->tv_sec - b->tv_sec - (a->tv_nsec < b->tv_nsec);
  38         res->tv_nsec = a->tv_nsec - b->tv_nsec +
  39                        (a->tv_nsec < b->tv_nsec) * 1E9;
  40 }
  41
  42 static void
  43 usage(void)
  44 {
  45         die("usage: %s [-s]", argv0);
  46 }
  47
  48 int
  49 main(int argc, char *argv[])
  50 {
  51         struct sigaction act;
  52         struct timespec start, current, diff, intspec, wait;
  53         size_t i, len;
  54         int sflag, ret;
  55         char status[MAXLEN];
  56         const char *res;
  57
  58         sflag = 0;
  59         ARGBEGIN {
  60                 case 's':
  61                         sflag = 1;
  62                         break;
  63                 default:
  64                         usage();
  65         } ARGEND
  66
  67         if (argc) {
  68                 usage();
  69         }
  70
  71         memset(&act, 0, sizeof(act));
  72         act.sa_handler = terminate;
  73         sigaction(SIGINT,  &act, NULL);
  74         sigaction(SIGTERM, &act, NULL);
  75
  76         if (sflag) {
  77                 setbuf(stdout, NULL);
  78         }
  79
  80         if (!sflag && !(dpy = XOpenDisplay(NULL))) {
  81                 die("XOpenDisplay: Failed to open display");
  82         }
  83
  84         while (!done) {
  85                 if (clock_gettime(CLOCK_MONOTONIC, &start) < 0) {
  86                         die("clock_gettime:");
  87                 }
  88
  89                 status[0] = '\0';
  90                 for (i = len = 0; i < LEN(args); i++) {
  91                         if (!(res = args[i].func(args[i].args))) {
  92                                 res = unknown_str;
  93                         }
  94                         if ((ret = esnprintf(status + len, sizeof(status) - len,
  95                                             args[i].fmt, res)) < 0) {
  96                                 break;
  97                         }
  98                         len += ret;
  99                 }
 100
 101                 if (sflag) {
 102                         if (printf("%s\n", status) < 0) {
 103                                 die("printf:");
 104                         }
 105                 } else {
 106                         if (XStoreName(dpy, DefaultRootWindow(dpy), status) < 0) {
 107                                 die("XStoreName: Allocation failed");
 108                         }
 109                         XFlush(dpy);
 110                 }
 111
 112                 if (!done) {
 113                         if (clock_gettime(CLOCK_MONOTONIC, &current) < 0) {
 114                                 die("clock_gettime:");
 115                         }
 116                         difftimespec(&diff, &current, &start);
 117
 118                         intspec.tv_sec = interval / 1000;
 119                         intspec.tv_nsec = (interval % 1000) * 1E6;
 120                         difftimespec(&wait, &intspec, &diff);
 121
 122                         if (wait.tv_sec >= 0) {
 123                                 if (nanosleep(&wait, NULL) < 0 &&
 124                                     errno != EINTR) {
 125                                         die("nanosleep:");
 126                                 }
 127                         }
 128                 }
 129         }
 130
 131         if (!sflag) {
 132                 XStoreName(dpy, DefaultRootWindow(dpy), NULL);
 133                 if (XCloseDisplay(dpy) < 0) {
 134                         die("XCloseDisplay: Failed to close display");
 135                 }
 136         }
 137
 138         return 0;
 139 }