Run a command, restarting it on SIGHUP.

reload.c

#include <signal.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <sys/wait.h>

volatile sig_atomic_t pid = 0;

static void restart(int sig)
{
  kill(pid, SIGKILL);
}

void run(char** argv)
{
  pid = fork();

  if (pid < 0) {
    exit(1);
  }
  else if (pid == 0) {
    if (execvp(argv[0], argv) < 0) {
      kill(getppid(), SIGINT);
    }
  }
  else {
    int status;

    while (wait(&status) != pid);
  }
}

int main(int argc, char **argv)
{
    signal(SIGHUP, restart);

    int status;

    for (;;) {
      run(&argv[1]);
    }
}