slstatus/slstatus.c
Laslo Hunhold 9c9ce8a125 Check printf() for output errors
This way cases like

	$ slstatus -s > /dev/full

are properly caught and the program terminated with the proper return
code.
2018-05-22 13:25:47 +02:00

147 lines
2.6 KiB
C

/* See LICENSE file for copyright and license details. */
#include <errno.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <X11/Xlib.h>
#include "arg.h"
#include "slstatus.h"
#include "util.h"
struct arg {
const char *(*func)();
const char *fmt;
const char *args;
};
char buf[1024];
static int done;
static Display *dpy;
#include "config.h"
static void
terminate(const int signo)
{
(void)signo;
done = 1;
}
static void
difftimespec(struct timespec *res, struct timespec *a, struct timespec *b)
{
res->tv_sec = a->tv_sec - b->tv_sec - (a->tv_nsec < b->tv_nsec);
res->tv_nsec = a->tv_nsec - b->tv_nsec +
(a->tv_nsec < b->tv_nsec) * 1000000000;
}
static void
usage(void)
{
die("usage: %s [-so]", argv0);
}
int
main(int argc, char *argv[])
{
struct sigaction act;
struct timespec start, current, diff, intspec, wait;
size_t i, len;
int sflag, oflag, ret;
char status[MAXLEN];
const char *res;
sflag = oflag = 0;
ARGBEGIN {
case 's':
sflag = 1;
break;
case 'o':
oflag = 1;
break;
default:
usage();
} ARGEND
if (argc) {
usage();
}
memset(&act, 0, sizeof(act));
act.sa_handler = terminate;
sigaction(SIGINT, &act, NULL);
sigaction(SIGTERM, &act, NULL);
if (sflag) {
setbuf(stdout, NULL);
}
if (!sflag && !(dpy = XOpenDisplay(NULL))) {
die("XOpenDisplay: Failed to open display");
}
while (!done) {
if (clock_gettime(CLOCK_MONOTONIC, &start) < 0) {
die("clock_gettime:");
}
status[0] = '\0';
for (i = len = 0; i < LEN(args); i++) {
if (!(res = args[i].func(args[i].args))) {
res = unknown_str;
}
if ((ret = esnprintf(status + len, sizeof(status) - len,
args[i].fmt, res)) < 0) {
break;
}
len += ret;
}
if (sflag) {
if (printf("%s\n", status) < 0) {
die("printf:");
}
} else {
if (XStoreName(dpy, DefaultRootWindow(dpy), status) < 0) {
die("XStoreName: Allocation failed");
}
XFlush(dpy);
}
if (oflag) {
done = 1;
}
if (!done) {
if (clock_gettime(CLOCK_MONOTONIC, &current) < 0) {
die("clock_gettime:");
}
difftimespec(&diff, &current, &start);
intspec.tv_sec = interval / 1000;
intspec.tv_nsec = (interval % 1000) * 1000000;
difftimespec(&wait, &intspec, &diff);
if (wait.tv_sec >= 0) {
if (nanosleep(&wait, NULL) < 0 &&
errno != EINTR) {
die("nanosleep:");
}
}
}
}
if (!sflag) {
XStoreName(dpy, DefaultRootWindow(dpy), NULL);
if (XCloseDisplay(dpy) < 0) {
die("XCloseDisplay: Failed to close display");
}
}
return 0;
}