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 volatile sig_atomic_t done;
  22 static Display *dpy;
  23
  24 #include "config.h"
  25
  26 static void
  27 terminate(const int signo)
  28 {
  29         if (signo != SIGUSR1)
  30                 done = 1;
  31 }
  32
  33 static void
  34 difftimespec(struct timespec *res, struct timespec *a, struct timespec *b)
  35 {
  36         res->tv_sec = a->tv_sec - b->tv_sec - (a->tv_nsec < b->tv_nsec);
  37         res->tv_nsec = a->tv_nsec - b->tv_nsec +
  38                        (a->tv_nsec < b->tv_nsec) * 1E9;
  39 }
  40
  41 static void
  42 usage(void)
  43 {
  44         die("usage: %s [-s]", argv0);
  45 }
  46
  47 int
  48 main(int argc, char *argv[])
  49 {
  50         struct sigaction act;
  51         struct timespec start, current, diff, intspec, wait;
  52         size_t i, len;
  53         int sflag, ret;
  54         char status[MAXLEN];
  55         const char *res;
  56
  57         sflag = 0;
  58         ARGBEGIN {
  59                 case 's':
  60                         sflag = 1;
  61                         break;
  62                 default:
  63                         usage();
  64         } ARGEND
  65
  66         if (argc) {
  67                 usage();
  68         }
  69
  70         memset(&act, 0, sizeof(act));
  71         act.sa_handler = terminate;
  72         sigaction(SIGINT,  &act, NULL);
  73         sigaction(SIGTERM, &act, NULL);
  74         act.sa_flags |= SA_RESTART;
  75         sigaction(SIGUSR1, &act, NULL);
  76
  77         if (!sflag && !(dpy = XOpenDisplay(NULL))) {
  78                 die("XOpenDisplay: Failed to open display");
  79         }
  80
  81         while (!done) {
  82                 if (clock_gettime(CLOCK_MONOTONIC, &start) < 0) {
  83                         die("clock_gettime:");
  84                 }
  85
  86                 status[0] = '\0';
  87                 for (i = len = 0; i < LEN(args); i++) {
  88                         if (!(res = args[i].func(args[i].args))) {
  89                                 res = unknown_str;
  90                         }
  91                         if ((ret = esnprintf(status + len, sizeof(status) - len,
  92                                             args[i].fmt, res)) < 0) {
  93                                 break;
  94                         }
  95                         len += ret;
  96                 }
  97
  98                 if (sflag) {
  99                         puts(status);
 100                         fflush(stdout);
 101                         if (ferror(stdout))
 102                                 die("puts:");
 103                 } else {
 104                         if (XStoreName(dpy, DefaultRootWindow(dpy), status)
 105                             < 0) {
 106                                 die("XStoreName: Allocation failed");
 107                         }
 108                         XFlush(dpy);
 109                 }
 110
 111                 if (!done) {
 112                         if (clock_gettime(CLOCK_MONOTONIC, &current) < 0) {
 113                                 die("clock_gettime:");
 114                         }
 115                         difftimespec(&diff, &current, &start);
 116
 117                         intspec.tv_sec = interval / 1000;
 118                         intspec.tv_nsec = (interval % 1000) * 1E6;
 119                         difftimespec(&wait, &intspec, &diff);
 120
 121                         if (wait.tv_sec >= 0) {
 122                                 if (nanosleep(&wait, NULL) < 0 &&
 123                                     errno != EINTR) {
 124                                         die("nanosleep:");
 125                                 }
 126                         }
 127                 }
 128         }
 129
 130         if (!sflag) {
 131                 XStoreName(dpy, DefaultRootWindow(dpy), NULL);
 132                 if (XCloseDisplay(dpy) < 0) {
 133                         die("XCloseDisplay: Failed to close display");
 134                 }
 135         }
 136
 137         return 0;
 138 }