dwmblocks.c

#include<stdlib.h>
#include<stdio.h>
#include<string.h>
#include<unistd.h>
#include<signal.h>
#include<X11/Xlib.h>
#ifdef __OpenBSD__
#define SIGPLUS			SIGUSR1+1
#define SIGMINUS		SIGUSR1-1
#else
#define SIGPLUS			SIGRTMIN
#define SIGMINUS		SIGRTMIN
#endif
#define LENGTH(X)               (sizeof(X) / sizeof (X[0]))
#define CMDLENGTH		50
#define MIN( a, b ) ( ( a < b) ? a : b )
#define STATUSLENGTH (LENGTH(blocks) * CMDLENGTH + 1)

typedef struct {
	char* icon;
	char* command;
	unsigned int interval;
	unsigned int signal;
} Block;
#ifndef __OpenBSD__
void dummysighandler(int num);
#endif
void sighandler(int num);
void buttonhandler(int sig, siginfo_t *si, void *ucontext);
void getcmds(int time);
void getsigcmds(unsigned int signal);
void setupsignals();
void sighandler(int signum);
int getstatus(char *str, char *last);
void setroot();
void statusloop();
void termhandler();


#include "blocks.h"

static Display *dpy;
static int screen;
static Window root;
static char statusbar[LENGTH(blocks)][CMDLENGTH] = {0};
static char statusstr[2][STATUSLENGTH];
static char button[] = "\0";
static int statusContinue = 1;
static void (*writestatus) () = setroot;

//opens process *cmd and stores output in *output
void getcmd(const Block *block, char *output)
{
	if (block->signal)
	{
		output[0] = block->signal;
		output++;
	}
	strcpy(output, block->icon);
	char *cmd = block->command;
	FILE *cmdf;
	if (*button)
	{
		setenv("BUTTON", button, 1);
		cmdf = popen(cmd,"r");
		*button = '\0';
		unsetenv("BUTTON");
	}
	else
	{
		cmdf = popen(cmd,"r");
	}
	if (!cmdf)
		return;
	int i = strlen(block->icon);
	fgets(output+i, CMDLENGTH-i-delimLen, cmdf);
	i = strlen(output);
	if (delim[0] != '\0') {
		//only chop off newline if one is present at the end
		i = output[i-1] == '\n' ? i-1 : i;
		strncpy(output+i, delim, delimLen); 
	}
	else
		output[i++] = '\0';
	pclose(cmdf);
}

void getcmds(int time)
{
	const Block* current;
	for (unsigned int i = 0; i < LENGTH(blocks); i++)
	{
		current = blocks + i;
		if ((current->interval != 0 && time % current->interval == 0) || time == -1)
			getcmd(current,statusbar[i]);
	}
}

void getsigcmds(unsigned int signal)
{
	const Block *current;
	for (unsigned int i = 0; i < LENGTH(blocks); i++)
	{
		current = blocks + i;
		if (current->signal == signal)
			getcmd(current,statusbar[i]);
	}
}

void setupsignals()
{
#ifndef __OpenBSD__
	    /* initialize all real time signals with dummy handler */
    for (int i = SIGRTMIN; i <= SIGRTMAX; i++)
        signal(i, dummysighandler);
#endif

	struct sigaction sa;
	sigemptyset(&sa.sa_mask);
	for (unsigned int i = 0; i < LENGTH(blocks); i++)
	{
		if (blocks[i].signal > 0)
		{
			signal(SIGMINUS+blocks[i].signal, sighandler);
			sigaddset(&sa.sa_mask, SIGRTMIN+blocks[i].signal); // ignore signal when handling SIGUSR1
		}
	}
	sa.sa_sigaction = buttonhandler;
	sa.sa_flags = SA_SIGINFO;
	sigaction(SIGUSR1, &sa, NULL);
}

int getstatus(char *str, char *last)
{
	strcpy(last, str);
	str[0] = '\0';
	for (unsigned int i = 0; i < LENGTH(blocks); i++)
		strcat(str, statusbar[i]);
	str[strlen(str)-strlen(delim)] = '\0';
	return strcmp(str, last);//0 if they are the same
}

void setroot()
{
	if (!getstatus(statusstr[0], statusstr[1]))//Only set root if text has changed.
		return;
	Display *d = XOpenDisplay(NULL);
	if (d) {
		dpy = d;
	}
	screen = DefaultScreen(dpy);
	root = RootWindow(dpy, screen);
	XStoreName(dpy, root, statusstr[0]);
	XCloseDisplay(dpy);
}

void pstdout()
{
	if (!getstatus(statusstr[0], statusstr[1]))//Only write out if text has changed.
		return;
	printf("%s\n",statusstr[0]);
	fflush(stdout);
}


void statusloop()
{
	setupsignals();
	int i = 0;
	getcmds(-1);
	while (statusContinue)
	{
		getcmds(i++);
		writestatus();
		sleep(1.0);
	}
}

#ifndef __OpenBSD__
/* this signal handler should do nothing */
void dummysighandler(int signum)
{
    return;
}
#endif

void sighandler(int signum)
{
	getsigcmds(signum-SIGPLUS);
	writestatus();
}

void buttonhandler(int sig, siginfo_t *si, void *ucontext)
{
	*button = '0' + si->si_value.sival_int & 0xff;
	getsigcmds(si->si_value.sival_int >> 8);
	writestatus();
}

void termhandler()
{
	statusContinue = 0;
}

int main(int argc, char** argv)
{
	for (int i = 0; i < argc; i++) //Handle command line arguments
	{
		if (!strcmp("-d",argv[i]))
			strncpy(delim, argv[++i], delimLen);
		else if (!strcmp("-p",argv[i]))
			writestatus = pstdout;
	}
	delimLen = MIN(delimLen, strlen(delim));
	delim[delimLen++] = '\0';
	signal(SIGTERM, termhandler);
	signal(SIGINT, termhandler);
	statusloop();
}