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#include <stdio.h>
#include <unistd.h>
#define MAX_ARGS 4
struct proc {
pid_t pid;
const char *filename;
const char *args[MAX_ARGS];
};
static struct proc spawn_table[] = {
// apple
{ 0, "bin/apple", { NULL } },
// end,
{ 0, NULL, { NULL } },
};
static int spawn(const char *filename, const char **args)
{
int ret;
// fork init
if ((ret = fork()) != 0)
return ret;
// call exec
if ((ret = exec(filename, args)))
exit(ret);
// should not happen!
exit(1);
}
int main(void)
{
struct proc *proc;
// spawn our processes
for (proc = spawn_table; proc->filename != NULL; proc++) {
int pid;
pid = spawn(proc->filename, proc->args);
if (pid < 0)
fprintf(stderr, "init: cannot exec '%s': %d\n", proc->filename,
pid);
proc->pid = pid;
}
// clean up dead on restart ours
while (1) {
int pid, status;
pid = waitpid(0, &status);
if (pid < 0)
continue;
printf("init: pid %d exited with %d\n", pid, status);
// figure out if this is one of ours
for (proc = spawn_table; proc->filename != NULL; proc++) {
if (proc->pid == pid) {
proc->pid = 0;
pid = spawn(proc->filename, proc->args);
if (pid < 0)
fprintf(stderr, "init: cannot exec '%s': %d\n",
proc->filename, pid);
proc->pid = pid;
break;
}
}
}
// very very bad!
return 1;
}
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