/*      $NetBSD: script.c,v 1.34 2023/05/09 15:43:39 hgutch Exp $       */

/*
 * Copyright (c) 1980, 1992, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * 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.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
 */

#include <sys/cdefs.h>
#ifndef lint
__COPYRIGHT("@(#) Copyright (c) 1980, 1992, 1993\
 The Regents of the University of California.  All rights reserved.");
#endif /* not lint */

#ifndef lint
#if 0
static char sccsid[] = "@(#)script.c    8.1 (Berkeley) 6/6/93";
#endif
__RCSID("$NetBSD: script.c,v 1.34 2023/05/09 15:43:39 hgutch Exp $");
#endif /* not lint */

#include <sys/types.h>
#include <sys/wait.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/time.h>
#include <sys/param.h>
#include <sys/uio.h>

#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <paths.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>
#include <time.h>
#include <tzfile.h>
#include <unistd.h>
#include <util.h>

#define DEF_BUF 65536

struct stamp {
        uint64_t scr_len;       /* amount of data */
        uint64_t scr_sec;       /* time it arrived in seconds... */
        uint32_t scr_usec;      /* ...and microseconds */
        uint32_t scr_direction; /* 'i', 'o', etc (also indicates endianness) */
};

static FILE     *fscript;
static int      master, slave;
static int      child, subchild;
static size_t   outcc;
static int      usesleep, rawout;
static int      quiet, flush;
static const char *fname;

static volatile sig_atomic_t die = 0;   /* exit if 1 */
static int      cstat = EXIT_SUCCESS;   /* cmd. exit status */
static int      eflag;
static int      isterm;
static struct   termios tt;

__dead static void      done(int);
__dead static void      doshell(const char *);
__dead static void      fail(void);
static sig_t    xsignal(int, sig_t);
__dead static void      dooutput(void);
static void     finish(int);
static void     scriptflush(int);
static void     record(FILE *, char *, size_t, int);
static void     consume(FILE *, off_t, char *, int);
__dead static void      playback(FILE *);

int
main(int argc, char *argv[])
{
        ssize_t scc;
        size_t cc;
        struct termios rtt;
        struct winsize win;
        int aflg, pflg, ch;
        char ibuf[BUFSIZ];
        const char *command;

        aflg = 0;
        pflg = 0;
        usesleep = 1;
        rawout = 0;
        quiet = 0;
        flush = 0;
        command = NULL;
        while ((ch = getopt(argc, argv, "ac:defpqr")) != -1)
                switch(ch) {
                case 'a':
                        aflg = 1;
                        break;
                case 'c':
                        command = optarg;
                        break;
                case 'd':
                        usesleep = 0;
                        break;
                case 'e':
                        eflag = 1;
                        break;
                case 'f':
                        flush = 1;
                        break;
                case 'p':
                        pflg = 1;
                        break;
                case 'q':
                        quiet = 1;
                        break;
                case 'r':
                        rawout = 1;
                        break;
                case '?':
                default:
                        (void)fprintf(stderr,
                            "Usage: %s [-c <command>][-adefpqr] [file]\n",
                            getprogname());
                        exit(EXIT_FAILURE);
                }
        argc -= optind;
        argv += optind;

        if (argc > 0)
                fname = argv[0];
        else
                fname = "typescript";

        if ((fscript = fopen(fname, pflg ? "r" : aflg ? "a" : "w")) == NULL)
                err(EXIT_FAILURE, "fopen %s", fname);

        if (pflg)
                playback(fscript);

        if (tcgetattr(STDIN_FILENO, &tt) == -1 ||
            ioctl(STDIN_FILENO, TIOCGWINSZ, &win) == -1) {
                if (errno != ENOTTY) /* For debugger. */
                        err(EXIT_FAILURE, "tcgetattr/ioctl");
                if (openpty(&master, &slave, NULL, NULL, NULL) == -1)
                        err(EXIT_FAILURE, "openpty");
        } else {
                if (openpty(&master, &slave, NULL, &tt, &win) == -1)
                        err(EXIT_FAILURE, "openpty");
                isterm = 1;
        }

        if (!quiet)
                (void)printf("Script started, output file is %s\n", fname);

        if (isterm) {
                rtt = tt;
                cfmakeraw(&rtt);
                rtt.c_lflag &= ~ECHO;
                (void)tcsetattr(STDIN_FILENO, TCSAFLUSH, &rtt);
        }

        (void)xsignal(SIGCHLD, finish);
        child = fork();
        if (child == -1) {
                warn("fork");
                fail();
        }
        if (child == 0) {
                (void)xsignal(SIGCHLD, SIG_DFL);
                subchild = child = fork();
                if (child == -1) {
                        warn("fork");
                        fail();
                }
                if (child)
                        dooutput();
                else
                        doshell(command);
        }

        if (!rawout)
                (void)fclose(fscript);
        while (!die && (scc = read(STDIN_FILENO, ibuf, BUFSIZ)) > 0) {
                cc = (size_t)scc;
                if (rawout)
                        record(fscript, ibuf, cc, 'i');
                (void)write(master, ibuf, cc);
        }
        done(cstat);
}

/**
 * wrapper around sigaction() because we want POSIX semantics:
 * no auto-restarting of interrupted slow syscalls.
 */
static sig_t
xsignal(int signo, sig_t handler)
{
        struct sigaction sa, osa;

        sa.sa_handler = handler;
        sa.sa_flags = 0;
        sigemptyset(&sa.sa_mask);
        if (sigaction(signo, &sa, &osa) == -1)
                return SIG_ERR;
        return osa.sa_handler;
}

static int
getshellstatus(int status)
{
        if (WIFEXITED(status))
                return WEXITSTATUS(status);
        if (WIFSIGNALED(status))
                return 128 + WTERMSIG(status);
        return EXIT_FAILURE;
}

static void
finish(int signo)
{
        int pid, status;

        die = 0;
        while ((pid = wait(&status)) > 0)
                if (pid == child) {
                        die = 1;
                }

        if (!die)
                return;
        done(eflag ? getshellstatus(status) : EXIT_SUCCESS);
}

static void
dooutput(void)
{
        struct itimerval value;
        ssize_t scc;
        size_t cc;
        time_t tvec;
        char obuf[BUFSIZ];

        (void)close(STDIN_FILENO);
        tvec = time(NULL);
        if (rawout)
                record(fscript, NULL, 0, 's');
        else if (!quiet)
                (void)fprintf(fscript, "Script started on %s", ctime(&tvec));

        (void)signal(SIGALRM, scriptflush);
        value.it_interval.tv_sec = SECSPERMIN / 2;
        value.it_interval.tv_usec = 0;
        value.it_value = value.it_interval;
        (void)setitimer(ITIMER_REAL, &value, NULL);
        for (;;) {
                scc = read(master, obuf, sizeof(obuf));
                if (scc <= 0)
                        break;
                cc = (size_t)scc;
                (void)write(STDOUT_FILENO, obuf, cc);
                if (rawout)
                        record(fscript, obuf, cc, 'o');
                else
                        (void)fwrite(obuf, 1, cc, fscript);
                outcc += cc;
                if (flush)
                        (void)fflush(fscript);
        }
        done(cstat);
}

static void
scriptflush(int signo)
{
        if (outcc) {
                (void)fflush(fscript);
                outcc = 0;
        }
}

static void
doshell(const char *command)
{
        const char *shell;

        (void)close(master);
        (void)fclose(fscript);
        login_tty(slave);
        if (command == NULL) {
                shell = getenv("SHELL");
                if (shell == NULL)
                        shell = _PATH_BSHELL;
                execl(shell, shell, "-i", NULL);
                warn("execl `%s'", shell);
        } else {
                int ret = system(command);
                if (ret == -1)
                        warn("system `%s'", command);
                else
                        exit(eflag ? getshellstatus(ret) : EXIT_FAILURE);
        }

        fail();
}

static void
fail(void)
{

        (void)kill(0, SIGTERM);
        done(EXIT_FAILURE);
}

static void
done(int status)
{
        time_t tvec;

        if (subchild) {
                tvec = time(NULL);
                if (rawout)
                        record(fscript, NULL, 0, 'e');
                else if (!quiet)
                        (void)fprintf(fscript,"\nScript done on %s",
                            ctime(&tvec));
                (void)fclose(fscript);
                (void)close(master);
        } else {
                if (isterm)
                        (void)tcsetattr(STDIN_FILENO, TCSAFLUSH, &tt);
                if (!quiet)
                        (void)printf("Script done, output file is %s\n", fname);
        }
        exit(status);
}

static void
record(FILE *fp, char *buf, size_t cc, int direction)
{
        struct iovec iov[2];
        struct stamp stamp;
        struct timeval tv;

        (void)gettimeofday(&tv, NULL);
        stamp.scr_len = cc;
        stamp.scr_sec = tv.tv_sec;
        stamp.scr_usec = tv.tv_usec;
        stamp.scr_direction = direction;
        iov[0].iov_len = sizeof(stamp);
        iov[0].iov_base = &stamp;
        iov[1].iov_len = cc;
        iov[1].iov_base = buf;
        if (writev(fileno(fp), &iov[0], 2) == -1)
                err(EXIT_FAILURE, "writev");
}

static void
consume(FILE *fp, off_t len, char *buf, int reg)
{
        size_t l;

        if (reg) {
                if (fseeko(fp, len, SEEK_CUR) == -1)
                        err(EXIT_FAILURE, NULL);
        }
        else {
                while (len > 0) {
                        l = MIN(DEF_BUF, len);
                        if (fread(buf, sizeof(char), l, fp) != l)
                                err(EXIT_FAILURE, "cannot read buffer");
                        len -= l;
                }
        }
}

#define swapstamp(stamp) do { \
        if (stamp.scr_direction > 0xff) { \
                stamp.scr_len = bswap64(stamp.scr_len); \
                stamp.scr_sec = bswap64(stamp.scr_sec); \
                stamp.scr_usec = bswap32(stamp.scr_usec); \
                stamp.scr_direction = bswap32(stamp.scr_direction); \
        } \
} while (0/*CONSTCOND*/)

static void
termset(void)
{
        struct termios traw;

        if (tcgetattr(STDOUT_FILENO, &tt) == -1) {
                if (errno != ENOTTY) /* For debugger. */
                        err(EXIT_FAILURE, "tcgetattr");
                return;
        }
        isterm = 1;
        traw = tt;
        cfmakeraw(&traw);
        traw.c_lflag |= ISIG;
        (void)tcsetattr(STDOUT_FILENO, TCSANOW, &traw);
}

static void
termreset(void)
{
        if (isterm)
                (void)tcsetattr(STDOUT_FILENO, TCSADRAIN, &tt);

        isterm = 0;
}

static void
playback(FILE *fp)
{
        struct timespec tsi, tso;
        struct stamp stamp;
        struct stat pst;
        char buf[DEF_BUF];
        off_t nread, save_len;
        size_t l;
        time_t tclock;
        int reg;

        if (fstat(fileno(fp), &pst) == -1)
                err(EXIT_FAILURE, "fstat failed");

        reg = S_ISREG(pst.st_mode);

        for (nread = 0; !reg || nread < pst.st_size; nread += save_len) {
                if (fread(&stamp, sizeof(stamp), 1, fp) != 1) {
                        if (reg)
                                err(EXIT_FAILURE, "reading playback header");
                        else
                                break;
                }
                swapstamp(stamp);
                save_len = sizeof(stamp);

                if (reg && stamp.scr_len >
                    (uint64_t)(pst.st_size - save_len) - nread)
                        errx(EXIT_FAILURE, "invalid stamp");

                save_len += stamp.scr_len;
                tclock = stamp.scr_sec;
                tso.tv_sec = stamp.scr_sec;
                tso.tv_nsec = stamp.scr_usec * 1000;

                switch (stamp.scr_direction) {
                case 's':
                        if (!quiet)
                            (void)printf("Script started on %s",
                                ctime(&tclock));
                        tsi = tso;
                        (void)consume(fp, stamp.scr_len, buf, reg);
                        termset();
                        atexit(termreset);
                        break;
                case 'e':
                        termreset();
                        if (!quiet)
                                (void)printf("\nScript done on %s",
                                    ctime(&tclock));
                        (void)consume(fp, stamp.scr_len, buf, reg);
                        break;
                case 'i':
                        /* throw input away */
                        (void)consume(fp, stamp.scr_len, buf, reg);
                        break;
                case 'o':
                        tsi.tv_sec = tso.tv_sec - tsi.tv_sec;
                        tsi.tv_nsec = tso.tv_nsec - tsi.tv_nsec;
                        if (tsi.tv_nsec < 0) {
                                tsi.tv_sec -= 1;
                                tsi.tv_nsec += 1000000000;
                        }
                        if (usesleep)
                                (void)nanosleep(&tsi, NULL);
                        tsi = tso;
                        while (stamp.scr_len > 0) {
                                l = MIN(DEF_BUF, stamp.scr_len);
                                if (fread(buf, sizeof(char), l, fp) != l)
                                        err(EXIT_FAILURE, "cannot read buffer");

                                (void)write(STDOUT_FILENO, buf, l);
                                stamp.scr_len -= l;
                        }
                        break;
                default:
                        errx(EXIT_FAILURE, "invalid direction %u",
                            stamp.scr_direction);
                }
        }
        (void)fclose(fp);
        exit(EXIT_SUCCESS);
}