dwmblocks/dwmblocks.c

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12 KiB
C
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#include <errno.h>
#include <fcntl.h>
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#include <limits.h>
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#include <signal.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
#include <unistd.h>
#include <X11/Xlib.h>
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#define CMDLENGTH 25
#define STTLENGTH 256
#define NILL INT_MIN
#define LOCKFILE "/tmp/dwmblocks.pid"
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typedef struct {
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char *pathu;
char *pathc;
const int interval;
const int signal;
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char cmdoutcur[CMDLENGTH];
char cmdoutprv[CMDLENGTH];
} Block;
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#include "blocks.h"
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static void buttonhandler(int signal, siginfo_t *si, void *ucontext);
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static void getcmd(Block *block, int sigval);
static void setroot();
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static void setupsignals();
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static void sighandler(int signal, siginfo_t *si, void *ucontext);
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static void statusloop();
static void termhandler(int signum);
static int updatestatus();
static void writepid();
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static int statuscontinue = 1;
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static char statusstr[STTLENGTH];
static size_t delimlength;
static Display *dpy;
static sigset_t blocksigmask;
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void
buttonhandler(int signal, siginfo_t *si, void *ucontext)
{
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signal = si->si_value.sival_int >> 8;
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for (Block *current = blocks; current->pathu; current++)
if (current->signal == signal)
switch (fork()) {
case -1:
perror("buttonhandler - fork");
break;
case 0:
{
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char button[] = { '0' + (si->si_value.sival_int & 0xff), '\0' };
char *arg[] = { current->pathc, button, NULL };
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close(ConnectionNumber(dpy));
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setsid();
execv(arg[0], arg);
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perror("buttonhandler - child - execv");
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_exit(127);
}
}
}
void
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getcmd(Block *block, int sigval)
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{
int fd[2];
if (pipe(fd) == -1) {
perror("getcmd - pipe");
exit(1);
}
switch (fork()) {
case -1:
perror("getcmd - fork");
exit(1);
case 0:
close(ConnectionNumber(dpy));
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close(fd[0]);
if (fd[1] != STDOUT_FILENO) {
if (dup2(fd[1], STDOUT_FILENO) != STDOUT_FILENO) {
perror("getcmd - child - dup2");
exit(1);
}
close(fd[1]);
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}
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if (sigval == NILL) {
char *arg[] = { block->pathu, NULL };
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execv(arg[0], arg);
} else {
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char buf[12];
char *arg[] = { block->pathu, buf, NULL };
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snprintf(buf, sizeof buf, "%d", sigval);
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execv(arg[0], arg);
}
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perror("getcmd - child - execv");
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_exit(127);
default:
close(fd[1]);
if (read(fd[0], block->cmdoutcur, CMDLENGTH) == -1) {
perror("getcmd - read");
exit(1);
}
close(fd[0]);
}
}
void
setroot()
{
if (updatestatus()) {
XStoreName(dpy, DefaultRootWindow(dpy), statusstr);
XSync(dpy, False);
}
}
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void
setupsignals()
{
struct sigaction sa;
/* to handle HUP, INT and TERM */
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sa.sa_flags = SA_RESTART;
sigemptyset(&sa.sa_mask);
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sa.sa_handler = termhandler;
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sigaction(SIGHUP, &sa, NULL);
sigaction(SIGINT, &sa, NULL);
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sigaction(SIGTERM, &sa, NULL);
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/* to ignore unused realtime signals */
// sa.sa_flags = SA_RESTART;
// sigemptyset(&sa.sa_mask);
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sa.sa_handler = SIG_IGN;
for (int i = SIGRTMIN + 1; i <= SIGRTMAX; i++)
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sigaction(i, &sa, NULL);
/* to prevent forked children from becoming zombies */
sa.sa_flags = SA_NOCLDSTOP | SA_NOCLDWAIT | SA_RESTART;
// sigemptyset(&sa.sa_mask);
sa.sa_handler = SIG_DFL;
sigaction(SIGCHLD, &sa, NULL);
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/* to handle signals generated by dwm on click events */
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sa.sa_flags = SA_RESTART | SA_SIGINFO;
// sigemptyset(&sa.sa_mask);
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sa.sa_sigaction = buttonhandler;
sigaction(SIGRTMIN, &sa, NULL);
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/* to handle update signals for individual blocks */
sa.sa_flags |= SA_NODEFER;
sa.sa_mask = blocksigmask;
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sa.sa_sigaction = sighandler;
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for (Block *current = blocks; current->pathu; current++)
if (current->signal > 0)
sigaction(SIGRTMIN + current->signal, &sa, NULL);
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}
void
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sighandler(int signal, siginfo_t *si, void *ucontext)
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{
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signal -= SIGRTMIN;
for (Block *current = blocks; current->pathu; current++)
if (current->signal == signal)
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getcmd(current, si->si_value.sival_int);
setroot();
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}
void
statusloop()
{
int i;
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/* first run */
sigprocmask(SIG_BLOCK, &blocksigmask, NULL);
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for (Block *current = blocks; current->pathu; current++)
if (current->interval >= 0)
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getcmd(current, NILL);
setroot();
sigprocmask(SIG_UNBLOCK, &blocksigmask, NULL);
sleep(SLEEPINTERVAL);
i = SLEEPINTERVAL;
/* main loop */
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while (statuscontinue) {
sigprocmask(SIG_BLOCK, &blocksigmask, NULL);
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for (Block *current = blocks; current->pathu; current++)
if (current->interval > 0 && i % current->interval == 0)
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getcmd(current, NILL);
setroot();
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sigprocmask(SIG_UNBLOCK, &blocksigmask, NULL);
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sleep(SLEEPINTERVAL);
i += SLEEPINTERVAL;
}
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}
void
termhandler(int signum)
{
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statuscontinue = 0;
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}
/* returns whether block outputs have changed and updates statusstr if they have */
int
updatestatus()
{
char *s = statusstr;
char *c, *p; /* for cmdoutcur and cmdoutprv */
const char *d; /* for delimiter */
Block *current = blocks;
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/* checking half of the function */
/* find the first non-empty block */
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for (;; current++) {
/* all blocks are empty */
if (!current->pathu)
return 0;
/* contents of the current block just changed */
if (*current->cmdoutcur != *current->cmdoutprv)
goto update0;
/* no delimiter before the first non-empty block */
if (*current->cmdoutcur != '\n' && *current->cmdoutcur != '\0')
goto skipdelimc;
}
/* main loop */
for (; current->pathu; current++) {
/* contents of the current block just changed */
if (*current->cmdoutcur != *current->cmdoutprv)
goto update1;
/* delimiter handler */
/* current block is non-empty */
if (*current->cmdoutcur != '\n' && *current->cmdoutcur != '\0')
s += delimlength;
/* skip over empty blocks */
else
continue;
skipdelimc:
/* checking for the first byte has been done */
c = current->cmdoutcur + 1, p = current->cmdoutprv + 1;
for (; *c != '\n' && *c != '\0'; c++, p++)
/* contents of the current block just changed */
if (*c != *p) {
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s += c - current->cmdoutcur;
goto update2;
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}
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s += c - current->cmdoutcur;
/* byte containing info about signal number for the block */
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if (current->pathc && current->signal)
s++;
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}
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return 0;
/* updating half of the function */
/* find the first non-empty block */
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for (;; current++) {
/* all blocks are empty */
if (!current->pathu)
return 1;
update0:
/* skip delimiter before the first non-empty block */
if (*current->cmdoutcur != '\n' && *current->cmdoutcur != '\0')
goto skipdelimu;
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*current->cmdoutprv = *current->cmdoutcur;
}
/* main loop */
for (; current->pathu; current++) {
update1:
/* delimiter handler */
/* current block is non-empty */
if (*current->cmdoutcur != '\n' && *current->cmdoutcur != '\0') {
d = delim;
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while (*d != '\0')
*(s++) = *(d++);
*(s++) = '\n'; /* to mark the end of delimiter */
/* skip over empty blocks */
} else {
*current->cmdoutprv = *current->cmdoutcur;
continue;
}
skipdelimu:
c = current->cmdoutcur, p = current->cmdoutprv;
update2:
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do {
*(s++) = *c;
*p = *c;
c++, p++;
} while (*c != '\n' && *c != '\0');
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if (current->pathc && current->signal)
*(s++) = current->signal;
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}
*s = '\0';
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return 1;
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}
void
writepid()
{
int fd;
struct flock fl;
fd = open(LOCKFILE, O_RDWR|O_CREAT, 0644);
if (fd == -1) {
perror("writepid - fd");
exit(1);
}
fl.l_type = F_WRLCK;
fl.l_start = 0;
fl.l_whence = SEEK_SET;
fl.l_len = 0;
if (fcntl(fd, F_SETLK, &fl) == -1) {
if (errno == EACCES || errno == EAGAIN) {
fputs("Error: another instance of dwmblocks is already running.\n", stderr);
exit(2);
}
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perror("writepid - fcntl");
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exit(1);
}
if (ftruncate(fd, 0) == -1) {
perror("writepid - ftruncate");
exit(1);
}
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if (dprintf(fd, "%ld", (long)getpid()) < 0) {
perror("writepid - dprintf");
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exit(1);
}
}
int
main(int argc, char *argv[])
{
writepid();
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if (argc > 2)
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if (strcmp(argv[1], "-d") == 0)
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delim = argv[2];
delimlength = strlen(delim) + 1;
if (!(dpy = XOpenDisplay(NULL))) {
fputs("Error: could not open display.\n", stderr);
return 1;
}
sigemptyset(&blocksigmask);
sigaddset(&blocksigmask, SIGHUP);
sigaddset(&blocksigmask, SIGINT);
sigaddset(&blocksigmask, SIGTERM);
for (Block *current = blocks; current->pathu; current++)
if (current->signal > 0)
sigaddset(&blocksigmask, SIGRTMIN + current->signal);
setupsignals();
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statusloop();
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unlink(LOCKFILE);
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XStoreName(dpy, DefaultRootWindow(dpy), "");
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XCloseDisplay(dpy);
return 0;
}