slstatus.c

   1 /* See LICENSE file for copyright and license details. */
   2 #include <errno.h>
   3 #include <locale.h>
   4 #include <signal.h>
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7 #include <string.h>
   8 #include <time.h>
   9 #include <X11/Xlib.h>
  10
  11 #include "arg.h"
  12 #include "slstatus.h"
  13 #include "util.h"
  14
  15 struct arg {
  16         const char *(*func)();
  17         const char *fmt;
  18         const char *args;
  19 };
  20
  21 char *argv0;
  22 char buf[1024];
  23 static int done;
  24 static Display *dpy;
  25
  26 #include "config.h"
  27
  28 static void
  29 terminate(const int signo)
  30 {
  31         (void)signo;
  32
  33         done = 1;
  34 }
  35
  36 static void
  37 difftimespec(struct timespec *res, struct timespec *a, struct timespec *b)
  38 {
  39         res->tv_sec = a->tv_sec - b->tv_sec - (a->tv_nsec < b->tv_nsec);
  40         res->tv_nsec = a->tv_nsec - b->tv_nsec +
  41                        (a->tv_nsec < b->tv_nsec) * 1000000000;
  42 }
  43
  44 static void
  45 usage(void)
  46 {
  47         fprintf(stderr, "usage: %s [-s]\n", argv0);
  48         exit(1);
  49 }
  50
  51 int
  52 main(int argc, char *argv[])
  53 {
  54         struct sigaction act;
  55         struct timespec start, current, diff, intspec, wait;
  56         size_t i, len;
  57         int sflag, ret;
  58         char status[MAXLEN];
  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         setlocale(LC_ALL, "");
  74
  75         memset(&act, 0, sizeof(act));
  76         act.sa_handler = terminate;
  77         sigaction(SIGINT,  &act, NULL);
  78         sigaction(SIGTERM, &act, NULL);
  79
  80         if (!sflag && !(dpy = XOpenDisplay(NULL))) {
  81                 fprintf(stderr, "Cannot open display");
  82                 return 1;
  83         }
  84
  85         while (!done) {
  86                 clock_gettime(CLOCK_MONOTONIC, &start);
  87
  88                 status[0] = '\0';
  89                 for (i = len = 0; i < LEN(args); i++) {
  90                         const char * res = args[i].func(args[i].args);
  91                         res = (res == NULL) ? unknown_str : res;
  92                         if ((ret = snprintf(status + len, sizeof(status) - len,
  93                                             args[i].fmt, res)) < 0) {
  94                                 fprintf(stderr, "snprintf: %s\n",
  95                                         strerror(errno));
  96                                 break;
  97                         } else if ((size_t)ret >= sizeof(status) - len) {
  98                                 fprintf(stderr, "snprintf: Output truncated\n");
  99                                 break;
 100                         }
 101                         len += ret;
 102                 }
 103
 104                 if (sflag) {
 105                         printf("%s\n", status);
 106                         fflush(stdout);
 107                 } else {
 108                         XStoreName(dpy, DefaultRootWindow(dpy), status);
 109                         XSync(dpy, False);
 110                 }
 111
 112                 if (!done) {
 113                         clock_gettime(CLOCK_MONOTONIC, &current);
 114                         difftimespec(&diff, &current, &start);
 115
 116                         intspec.tv_sec = interval / 1000;
 117                         intspec.tv_nsec = (interval % 1000) * 1000000;
 118                         difftimespec(&wait, &intspec, &diff);
 119
 120                         if (wait.tv_sec >= 0) {
 121                                 nanosleep(&wait, NULL);
 122                         }
 123                 }
 124         }
 125
 126         if (!sflag) {
 127                 XStoreName(dpy, DefaultRootWindow(dpy), NULL);
 128                 XCloseDisplay(dpy);
 129         }
 130
 131         return 0;
 132 }