/*      $NetBSD: unfdpass.c,v 1.12 2021/08/08 20:54:48 nia Exp $        */

/*-
 * Copyright (c) 1998 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
 * NASA Ames Research Center.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * Test passing of file descriptors and credentials over Unix domain sockets.
 */

#include <sys/param.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <sys/un.h>
#include <sys/uio.h>
#include <sys/stat.h>

#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>

#define SOCK_NAME       "test-sock"

int     main(int, char *[]);
void    child(void);
void    catch_sigchld(int);
void    usage(char *progname);

#define FILE_SIZE       128
#define MSG_SIZE        -1
#define NFILES          24

#define FDCM_DATASIZE   (sizeof(int) * NFILES)
#define CRCM_DATASIZE   (SOCKCREDSIZE(NGROUPS))

#define MESSAGE_SIZE    (CMSG_SPACE(FDCM_DATASIZE) +                    \
                         CMSG_SPACE(CRCM_DATASIZE))

int chroot_rcvr = 0;
int pass_dir = 0;
int pass_root_dir = 0;
int exit_early = 0;
int exit_later = 0;
int pass_sock = 0;
int make_pretzel = 0;

/* ARGSUSED */
int
main(argc, argv)
        int argc;
        char *argv[];
{
#if MSG_SIZE >= 0
        struct iovec iov;
#endif
        char *progname=argv[0];
        struct msghdr msg;
        int listensock, sock, fd, i;
        char fname[16], buf[FILE_SIZE];
        struct cmsghdr *cmp;
        void *message;
        int *files = NULL;
        struct sockcred *sc = NULL;
        struct sockaddr_un sun, csun;
        socklen_t csunlen;
        pid_t pid;
        int ch;

        message = malloc(CMSG_SPACE(MESSAGE_SIZE));
        if (message == NULL)
                err(1, "unable to malloc message buffer");
        memset(message, 0, CMSG_SPACE(MESSAGE_SIZE));

        while ((ch = getopt(argc, argv, "DESdepr")) != -1) {
                switch(ch) {

                case 'e':
                        exit_early++; /* test early GC */
                        break;

                case 'E':
                        exit_later++; /* test later GC */
                        break;
                        
                case 'd':
                        pass_dir++;
                        break;
                        
                case 'D':
                        pass_dir++;
                        pass_root_dir++;
                        break;

                case 'S':
                        pass_sock++;
                        break;

                case 'r':
                        chroot_rcvr++;
                        break;

                case 'p':
                        make_pretzel++;
                        break;
                        
                case '?':
                default:
                        usage(progname);
                }
        }


        /*
         * Create the test files.
         */
        for (i = 0; i < NFILES; i++) {
                (void) sprintf(fname, "file%d", i + 1);
                if ((fd = open(fname, O_WRONLY|O_CREAT|O_TRUNC, 0666)) == -1)
                        err(1, "open %s", fname);
                (void) sprintf(buf, "This is file %d.\n", i + 1);
                if (write(fd, buf, strlen(buf)) != strlen(buf))
                        err(1, "write %s", fname);
                (void) close(fd);
        }

        /*
         * Create the listen socket.
         */
        if ((listensock = socket(PF_LOCAL, SOCK_STREAM, 0)) == -1)
                err(1, "socket");

        (void) unlink(SOCK_NAME);
        (void) memset(&sun, 0, sizeof(sun));
        sun.sun_family = AF_LOCAL;
        (void) strcpy(sun.sun_path, SOCK_NAME);
        sun.sun_len = SUN_LEN(&sun);

        i = 1;
        if (setsockopt(listensock, SOL_LOCAL, LOCAL_CREDS, &i, sizeof(i)) == -1)
                err(1, "setsockopt");

        if (bind(listensock, (struct sockaddr *)&sun, sizeof(sun)) == -1)
                err(1, "bind");

        if (listen(listensock, 1) == -1)
                err(1, "listen");

        /*
         * Create the sender.
         */
        (void) signal(SIGCHLD, catch_sigchld);
        pid = fork();
        switch (pid) {
        case -1:
                err(1, "fork");
                /* NOTREACHED */

        case 0:
                child();
                /* NOTREACHED */
        }

        if (exit_early)
                exit(0);
        
        if (chroot_rcvr &&
            ((chroot(".") < 0)))
                err(1, "chroot");
        
        /*
         * Wait for the sender to connect.
         */
        csunlen = sizeof(csun);
        if ((sock = accept(listensock, (struct sockaddr *)&csun,
            &csunlen)) == -1)
                err(1, "accept");

        /*
         * Give sender a chance to run.  We will get going again
         * once the SIGCHLD arrives.
         */
        (void) sleep(10);

        if (exit_later)
                exit(0);
        
        /*
         * Grab the descriptors and credentials passed to us.
         */

        /* Expect 2 messages; descriptors and creds. */
        do {
                (void) memset(&msg, 0, sizeof(msg));
                msg.msg_control = message;
                msg.msg_controllen = MESSAGE_SIZE;
#if MSG_SIZE >= 0
                iov.iov_base = buf;
                iov.iov_len = MSG_SIZE;
                msg.msg_iov = &iov;
                msg.msg_iovlen = 1;
#endif

                if (recvmsg(sock, &msg, 0) == -1)
                        err(1, "recvmsg");

                (void) close(sock);
                sock = -1;

                if (msg.msg_controllen == 0)
                        errx(1, "no control messages received");

                if (msg.msg_flags & MSG_CTRUNC)
                        errx(1, "lost control message data");

                for (cmp = CMSG_FIRSTHDR(&msg); cmp != NULL;
                     cmp = CMSG_NXTHDR(&msg, cmp)) {
                        if (cmp->cmsg_level != SOL_SOCKET)
                                errx(1, "bad control message level %d",
                                    cmp->cmsg_level);

                        switch (cmp->cmsg_type) {
                        case SCM_RIGHTS:
                                if (cmp->cmsg_len != CMSG_LEN(FDCM_DATASIZE))
                                        errx(1, "bad fd control message "
                                            "length %d", cmp->cmsg_len);

                                files = (int *)CMSG_DATA(cmp);
                                break;

                        case SCM_CREDS:
                                if (cmp->cmsg_len < CMSG_LEN(SOCKCREDSIZE(1)))
                                        errx(1, "bad cred control message "
                                            "length %d", cmp->cmsg_len);

                                sc = (struct sockcred *)CMSG_DATA(cmp);
                                break;

                        default:
                                errx(1, "unexpected control message");
                                /* NOTREACHED */
                        }
                }

                /*
                 * Read the files and print their contents.
                 */
                if (files == NULL)
                        warnx("didn't get fd control message");
                else {
                        for (i = 0; i < NFILES; i++) {
                                struct stat st;
                                (void) memset(buf, 0, sizeof(buf));
                                fstat(files[i], &st);
                                if (S_ISDIR(st.st_mode)) {
                                        printf("file %d is a directory\n", i+1);
                                } else if (S_ISSOCK(st.st_mode)) {
                                        printf("file %d is a socket\n", i+1);
                                        sock = files[i];
                                } else {
                                        int c;
                                        c = read (files[i], buf, sizeof(buf));
                                        if (c < 0)
                                                err(1, "read file %d", i + 1);
                                        else if (c == 0)
                                                printf("[eof on %d]\n", i + 1);
                                        else
                                                printf("%s", buf);
                                }
                        }
                }
                /*
                 * Double-check credentials.
                 */
                if (sc == NULL)
                        warnx("didn't get cred control message");
                else {
                        if (sc->sc_uid == getuid() &&
                            sc->sc_euid == geteuid() &&
                            sc->sc_gid == getgid() &&
                            sc->sc_egid == getegid())
                                printf("Credentials match.\n");
                        else
                                printf("Credentials do NOT match.\n");
                }
        } while (sock != -1);

        /*
         * All done!
         */
        exit(0);
}

void
usage(progname)
        char *progname;
{
        fprintf(stderr, "usage: %s [-derDES]\n", progname);
        exit(1);
}

void
catch_sigchld(sig)
        int sig;
{
        int status;

        (void) wait(&status);
}

void
child()
{
#if MSG_SIZE >= 0
        struct iovec iov;
#endif
        struct msghdr msg;
        char fname[16];
        struct cmsghdr *cmp;
        void *fdcm;
        int i, fd, sock, nfd, *files;
        struct sockaddr_un sun;
        int spair[2];

        fdcm = malloc(CMSG_SPACE(FDCM_DATASIZE));
        if (fdcm == NULL)
                err(1, "unable to malloc fd control message");
        memset(fdcm, 0, CMSG_SPACE(FDCM_DATASIZE));

        cmp = fdcm;
        files = (int *)CMSG_DATA(fdcm);

        /*
         * Create socket and connect to the receiver.
         */
        if ((sock = socket(PF_LOCAL, SOCK_STREAM, 0)) == -1)
                errx(1, "child socket");

        (void) memset(&sun, 0, sizeof(sun));
        sun.sun_family = AF_LOCAL;
        (void) strcpy(sun.sun_path, SOCK_NAME);
        sun.sun_len = SUN_LEN(&sun);

        if (connect(sock, (struct sockaddr *)&sun, sizeof(sun)) == -1)
                err(1, "child connect");

        nfd = NFILES;
        i = 0;

        if (pass_sock) {
                files[i++] = sock;
        }

        if (pass_dir)
                nfd--;

        /*
         * Open the files again, and pass them to the child
         * over the socket.
         */

        for (; i < nfd; i++) {
                (void) sprintf(fname, "file%d", i + 1);
                if ((fd = open(fname, O_RDONLY, 0666)) == -1)
                        err(1, "child open %s", fname);
                files[i] = fd;
        }
        
        if (pass_dir) {
                char *dirname = pass_root_dir ? "/" : ".";

                
                if ((fd = open(dirname, O_RDONLY, 0)) == -1) {
                        err(1, "child open directory %s", dirname);
                }
                files[i] = fd;
        }
        
        (void) memset(&msg, 0, sizeof(msg));
        msg.msg_control = fdcm;
        msg.msg_controllen = CMSG_LEN(FDCM_DATASIZE);
#if MSG_SIZE >= 0
        iov.iov_base = buf;
        iov.iov_len = MSG_SIZE;
        msg.msg_iov = &iov;
        msg.msg_iovlen = 1;
#endif

        cmp = CMSG_FIRSTHDR(&msg);
        cmp->cmsg_len = CMSG_LEN(FDCM_DATASIZE);
        cmp->cmsg_level = SOL_SOCKET;
        cmp->cmsg_type = SCM_RIGHTS;

        while (make_pretzel > 0) {
                if (socketpair(PF_LOCAL, SOCK_STREAM, 0, spair) < 0)
                        err(1, "socketpair");

                printf("send pretzel\n");
                if (sendmsg(spair[0], &msg, 0) < 0)
                        err(1, "child prezel sendmsg");

                close(files[0]);
                close(files[1]);                
                files[0] = spair[0];
                files[1] = spair[1];            
                make_pretzel--;
        }

        if (sendmsg(sock, &msg, 0) == -1)
                err(1, "child sendmsg");

        /*
         * All done!
         */
        exit(0);
}