reload-watcher.c

// just throwing shit at the wall
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include <libgen.h>
#include <sys/inotify.h>
#include <fcntl.h>
#include <unistd.h>
#include <signal.h>

#define EVENT_SIZE  ( sizeof (struct inotify_event) ) 

int fd;

int main(int argc, char** argv)
{
    char* argv0 = argv[0];
    if (argc <= 1)
    {
        fprintf(stderr, "%s: program [args]\n", argv0);
        return 0;
    }

    char* program = argv[1];
    char program_dir[PATH_MAX];
    char* program_name = basename(program);

    strncpy(program_dir, program, sizeof(program_dir)); 
    dirname(program_dir);

    realpath(program_dir, program_dir);

    char** args = argv + 1;


    fd = inotify_init();
    fcntl(fd, F_SETFL, O_NONBLOCK);

    puts(program_dir);
    inotify_add_watch(fd, program_dir, IN_MODIFY | IN_CREATE);

    while (1)
    {
        pid_t pid = fork();

        if (!pid)
        {
            execvp(program, args);
            return 0;
        }
        else
        {
            size_t event_size = (strlen(program) + strlen(program_dir) + EVENT_SIZE);
            char* event_buffer = (char*)malloc(event_size);

            int program_updated = 0;
            while(!program_updated)
            {
                int i = 0;
                int length = read(fd, event_buffer, event_size);

                while(i < length)
                {
                    struct inotify_event *event = (struct inotify_event *) &event_buffer[i];
         
                    if(event->len)
                    {
                        if ((event->mask & IN_CREATE ||
                             event->mask & IN_MODIFY) &&
                            !(event->mask & IN_ISDIR) &&
                            !strcmp(event->name, program_name))
                        {
                            program_updated = 1;
                        }
                    }
                    i += EVENT_SIZE + event->len;
                }
            }

            sleep(3);

            kill(pid, SIGKILL);
        }
    }
}