/*
 * vexec - Wrapper for command execution in a vserver
 *
 * Copyright 2005 Björn Steinbrink
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#include <pwd.h>

#define VDIRBASE "/etc/vservers/.defaults/vdirbase/"
#define PASSWD "/etc/passwd"

#define BASH "/bin/bash"
#define VSERVER "/usr/sbin/vserver"
#define CMD "exec"
#define SU "su"

void usage(char *name)
{
	printf("Usage:\n");
	printf("%s <vserver> <command>\n", name);
}

int main(int argc, char **argv)
{
	struct passwd *host_user, *vserver_user;
	FILE *vserver_passwd;
	char *vserver_passwd_path;
	int len;
	char **cmd;
	int i;

	if (argc < 3)
	{
		usage(argv[0]);
		exit(EXIT_FAILURE);
	}

	if ((host_user = getpwuid(getuid())) == NULL)
	{
		perror("getpwuid");
		exit(EXIT_FAILURE);
	}

	len = strlen(VDIRBASE) + strlen(argv[1]) + strlen(PASSWD) + 1;
	vserver_passwd_path = (char*)malloc(len);
	strcpy(vserver_passwd_path, VDIRBASE);
	strcat(vserver_passwd_path, argv[1]);
	strcat(vserver_passwd_path, PASSWD);
	if ((vserver_passwd = fopen(vserver_passwd_path, "r")) == NULL)
	{
		perror("fopen");
		exit(EXIT_FAILURE);
	}

	while ((vserver_user = fgetpwent(vserver_passwd)) != NULL)
	{
		if (!strcmp(host_user->pw_name, vserver_user->pw_name))
			break;
	}
	fclose(vserver_passwd);
	if (!vserver_user)
	{
		fprintf(stderr, "No user %s found in vserver %s\n",
				host_user->pw_name, argv[1]);
		exit(EXIT_FAILURE);
	}

	setuid(0);

	cmd = (char**)malloc(sizeof(char*) * (argc+4));
	cmd[0] = BASH;
	cmd[1] = VSERVER;
	cmd[2] = argv[1];
	cmd[3] = CMD;
	cmd[4] = SU;
	cmd[5] = "-";
	cmd[6] = vserver_user->pw_name;
	for (i = 2; i < argc; i++)
	{
		cmd[i+5] = argv[i];
	}
	cmd[i+5] = NULL;

	execv(cmd[0], cmd);
	perror("execv");

	fprintf(stderr, "Failed...!\n");

	exit(EXIT_FAILURE);
}