dwmblocks/sigdwmblocks.c
2021-01-10 05:26:10 +05:30

106 lines
2.7 KiB
C

#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#define NILL INT_MIN
#define LOCKFILE "/tmp/dwmblocks.pid"
int
parsesignal(char *arg, int *s)
{
int i = 0;
for (; *arg != '\0'; arg++)
if (*arg >= '0' && *arg <= '9')
i = 10 * i + *arg - '0';
else
return 0;
if ((i += SIGRTMIN) > SIGRTMAX)
return 0;
*s = i;
return 1;
}
int
parsesigval(char *arg, int *v)
{
int s = 1, i = 0;
if (*arg == '-') {
s = -1;
arg++;
} else if (*arg == '+')
arg++;
for (; *arg != '\0'; arg++)
if (*arg >= '0' && *arg <= '9')
i = 10 * i + *arg - '0';
else
return 0;
*v = s * i;
return 1;
}
void
sendsignal(int sig, union sigval sv)
{
int fd;
struct flock fl;
fd = open(LOCKFILE, O_RDONLY);
if (fd == -1) {
if (errno == ENOENT) {
fputs("Error: no running instance of dwmblocks.\n", stderr);
exit(3);
}
perror("sendsignal - open");
exit(1);
}
fl.l_type = F_WRLCK;
fl.l_whence = SEEK_SET;
fl.l_start = 0;
fl.l_len = 0;
if (fcntl(fd, F_GETLK, &fl) == -1) {
perror("sendsignal - fcntl");
close(fd);
exit(1);
}
close(fd);
if (fl.l_type == F_UNLCK) {
fputs("Error: no running instance of dwmblocks.\n", stderr);
exit(3);
}
if (sigqueue(fl.l_pid, sig, sv) == -1) {
if (errno == ESRCH) {
fputs("Error: no running instance of dwmblocks.\n", stderr);
exit(3);
} else {
perror("sendsignal - sigqueue");
exit(1);
}
}
}
int
main(int argc, char *argv[])
{
int sig;
union sigval sv;
if (argc > 1 && parsesignal(argv[1], &sig)) {
if (argc == 2) {
sv.sival_int = NILL;
sendsignal(sig, sv);
return 0;
} else if (argc == 3 && parsesigval(argv[2], &(sv.sival_int))) {
sendsignal(sig, sv);
return 0;
}
}
fprintf(stderr, "Usage: %s <signal> [<sigval>]\n", argv[0]);
return 2;
}