#include <stdio.h>
#include <unistd.h>
#include <errno.h>
#include <sys/wait.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <limits.h>
#include "util.h"
#include "interfere.h"

const char *progname="inject";

struct private
{
	int fd;
	char *text;
	size_t len;
};

int inject(struct process *proc, struct private *priv)
{
	PROC_BEGIN(proc);

	while (priv->len)
	{
		proc_write(proc, priv->fd, priv->text, priv->len);
		if (proc->last_error)
		{
			if (proc->last_error==EINTR)
				continue;
			warn("write(pid %li, fd %i): %s\n", 
			     (long)proc->pid, priv->fd,
			     strerror(proc->last_error));
			goto out;
		}
		priv->text+=proc->retval;
		priv->len-=proc->retval;
	}

 out:
	PROC_END(proc);
}

int main(int argc, char *argv[])
{
	pid_t pid;
	int status;
	struct process proc;
	struct private priv;

	if (argc>0) setprogname(argv[0]);
	if (argc<4) die("Usage: %s pid fd text\n", progname);

	pid=str_to_pid(argv[1]);
	priv.fd=str_to_fd(argv[2]);
	priv.text=argv[3];
	priv.len=strlen(argv[3]);

	if (pid==0) die("Invalid pid: 0\n");

	proc_init(&proc);
	proc_attach(&proc, pid);
		
	while (1)
	{
		pid=waitpid(proc.pid, &status, 0);
		if (pid==-1)
		{
			if (errno==EINTR) continue;
			if (errno==ECHILD) break;
			die("waitpid: %s\n", strerror(errno));
		}
		inject(&proc, &priv);
	}
	return 0;
}