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#include <libudev.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/select.h>
#include <sys/wait.h>
#include <unistd.h>
#define BLOCK_SIZE 512
#define STRNCMP(s, cs) strncmp(s, cs, strlen(cs))
int execute_shell_script() {
char *home = getenv("HOME");
if (!home) {
fprintf(stderr, "No home environment variable.");
return 1;
}
char script_path[4096];
snprintf(script_path, sizeof(script_path) - 1,
"%s/.xmonad/configure-displays", home);
int f = fork();
if (f == 0) {
// child process.
execl(script_path, script_path, "change", NULL);
perror("Exec failed");
exit(1);
} else {
if (f == -1) {
perror("Forking failed");
return 1;
} else {
waitpid(f, NULL, 0);
}
}
return 0;
}
int main() {
struct udev *udev;
struct udev_device *dev;
struct udev_monitor *mon;
int fd;
udev = udev_new();
if (!udev) {
fprintf(stderr, "Cannot create new udev context\n");
return 1;
}
mon = udev_monitor_new_from_netlink(udev, "udev");
udev_monitor_filter_add_match_subsystem_devtype(mon, "drm", NULL);
udev_monitor_enable_receiving(mon);
fd = udev_monitor_get_fd(mon);
int found_event = 0;
while (1) {
fd_set fds;
struct timeval to = {0};
if (found_event) {
to.tv_usec = 100000;
}
int ret;
FD_ZERO(&fds);
FD_SET(fd, &fds);
ret = select(fd + 1, &fds, NULL, NULL, found_event ? &to : NULL);
if (ret > 0 && FD_ISSET(fd, &fds)) {
dev = udev_monitor_receive_device(mon);
if (dev) {
if (STRNCMP(udev_device_get_action(dev), "change") == 0) {
printf("I: Change detected.\n");
found_event = 1;
// Still need to clean up some trailing detected changes.
}
}
} else if (ret == 0 && found_event) {
printf("Executing shell script hook.\n");
if (execute_shell_script()) {
fprintf(stderr, "Unable to execute shell script.");
};
found_event = 0;
}
}
}
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