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