core-agent-linux/qrexec/qrexec-client-vm.c

/*
 * The Qubes OS Project, http://www.qubes-os.org
 *
 * Copyright (C) 2010  Rafal Wojtczuk  <rafal@invisiblethingslab.com>
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 *
 */
#define _GNU_SOURCE
#include <sys/socket.h>
#include <sys/un.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include "qrexec.h"
int connect_unix_socket()
{
    int s, len;
    struct sockaddr_un remote;

    if ((s = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
        perror("socket");
        return -1;
    }

    remote.sun_family = AF_UNIX;
    strncpy(remote.sun_path, QREXEC_AGENT_FDPASS_PATH,
            sizeof(remote.sun_path));
    len = strlen(remote.sun_path) + sizeof(remote.sun_family);
    if (connect(s, (struct sockaddr *) &remote, len) == -1) {
        perror("connect");
        exit(1);
    }
    return s;
}

char *get_program_name(char *prog)
{
    char *basename = rindex(prog, '/');
    if (basename)
        return basename + 1;
    else
        return prog;
}

int main(int argc, char **argv)
{
    int trigger_fd;
    struct trigger_service_params params;
    int local_fd[3], remote_fd[3];
    int i;
    char *abs_exec_path;

    if (argc < 4) {
        fprintf(stderr,
                "usage: %s target_vmname program_ident local_program [local program arguments]\n",
                argv[0]);
        exit(1);
    }

    trigger_fd = open(QREXEC_AGENT_TRIGGER_PATH, O_WRONLY);
    if (trigger_fd < 0) {
        perror("open " QREXEC_AGENT_TRIGGER_PATH);
        exit(1);
    }

    for (i = 0; i < 3; i++) {
        local_fd[i] = connect_unix_socket();
        if (read(local_fd[i], &remote_fd[i], sizeof(remote_fd[i])) != sizeof(remote_fd[i])) {
            perror("read client fd");
            exit(1);
        }
        if (i != 2 || getenv("PASS_LOCAL_STDERR")) {
            char *env;
            if (asprintf(&env, "SAVED_FD_%d=%d", i, dup(i)) < 0) {
                perror("prepare SAVED_FD_");
                exit(1);
            }
            putenv(env);
            dup2(local_fd[i], i);
            close(local_fd[i]);
        } else
            close(local_fd[i]);
    }

    memset(&params, 0, sizeof(params));
    strncpy(params.service_name, argv[2], sizeof(params.service_name));
    strncpy(params.target_domain, argv[1],
            sizeof(params.target_domain));
    snprintf(params.request_id.ident,
            sizeof(params.request_id.ident), "%d %d %d",
            remote_fd[0], remote_fd[1], remote_fd[2]);

    if (write(trigger_fd, &params, sizeof(params)) < 0) {
        if (!getenv("PASS_LOCAL_STDERR"))
            perror("write to agent");
        exit(1);
    }

    close(trigger_fd);

    abs_exec_path = strdup(argv[3]);
    argv[3] = get_program_name(argv[3]);
    execv(abs_exec_path, argv + 3);
    perror("execv");
    return 1;
}