/*
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 2010, 2012  David E. O'Brien
 * 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/param.h>
#include <sys/wait.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <sys/time.h>
#include <sys/queue.h>
#include <sys/uio.h>
#include <sys/endian.h>
#include <dev/filemon/filemon.h>

#include <assert.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <libutil.h>
#include <paths.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>
#include <unistd.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) */
};

struct buf_elm {
        TAILQ_ENTRY(buf_elm) link;
        size_t rpos;
        size_t len;
        char ibuf[];
};

static FILE *fscript;
static int master, slave;
static int child;
static const char *fname;
static char *fmfname;
static int fflg, qflg, ttyflg;
static int usesleep, rawout, showexit;
static TAILQ_HEAD(, buf_elm) obuf_list = TAILQ_HEAD_INITIALIZER(obuf_list);
static volatile sig_atomic_t doresize;

static struct termios tt;

#ifndef TSTAMP_FMT
/* useful for tool and human reading */
# define TSTAMP_FMT "%n@ %s [%Y-%m-%d %T]%n"
#endif
static const char *tstamp_fmt = TSTAMP_FMT;
static int tflg;

static void done(int) __dead2;
static void doshell(char **);
static void finish(void);
static void record(FILE *, char *, size_t, int);
static void consume(FILE *, off_t, char *, int);
static void playback(FILE *) __dead2;
static void usage(void) __dead2;
static void resizeit(int);

int
main(int argc, char *argv[])
{
        struct termios rtt, stt;
        struct winsize win;
        struct timespec tv, *tvp;
        time_t tvec, start;
        char obuf[BUFSIZ];
        char ibuf[BUFSIZ];
        sigset_t *pselmask, selmask;
        fd_set rfd, wfd;
        struct buf_elm *be;
        ssize_t cc;
        int aflg, Fflg, kflg, pflg, wflg, ch, k, n, fcm;
        int flushtime, readstdin;
        int fm_fd, fm_log;

        aflg = Fflg = kflg = pflg = wflg = 0;
        doresize = 0;
        usesleep = 1;
        rawout = 0;
        flushtime = 30;
        fm_fd = -1;
        showexit = 0;

        /*
         * For normal operation, we'll leave pselmask == NULL so that pselect(2)
         * leaves the signal mask alone.  If -w is specified, we'll restore the
         * process signal mask upon entry with SIGWINCH unblocked so that we can
         * forward resize events properly.
         */
        sigemptyset(&selmask);
        pselmask = NULL;

        while ((ch = getopt(argc, argv, "adeFfkpqrT:t:w")) != -1)
                switch (ch) {
                case 'a':
                        aflg = 1;
                        break;
                case 'd':
                        usesleep = 0;
                        break;
                case 'e':
                        /* Default behavior, accepted for linux compat. */
                        break;
                case 'F':
                        Fflg = 1;
                        break;
                case 'f':
                        fflg = 1;
                        break;
                case 'k':
                        kflg = 1;
                        break;
                case 'p':
                        pflg = 1;
                        break;
                case 'q':
                        qflg = 1;
                        break;
                case 'r':
                        rawout = 1;
                        break;
                case 't':
                        flushtime = atoi(optarg);
                        if (flushtime < 0)
                                err(1, "invalid flush time %d", flushtime);
                        break;
                case 'T':
                        tflg = pflg = 1;
                        if (strchr(optarg, '%'))
                                tstamp_fmt = optarg;
                        break;
                case 'w':
                        wflg = 1;
                        break;
                case '?':
                default:
                        usage();
                }
        argc -= optind;
        argv += optind;

        if (argc > 0) {
                fname = argv[0];
                argv++;
                argc--;
        } else
                fname = "typescript";

        if ((fscript = fopen(fname, pflg ? "r" : aflg ? "a" : "w")) == NULL)
                err(1, "%s", fname);

        if (fflg) {
                asprintf(&fmfname, "%s.filemon", fname);
                if (!fmfname)
                        err(1, "%s.filemon", fname);
                if ((fm_fd = open("/dev/filemon", O_RDWR | O_CLOEXEC)) == -1)
                        err(1, "open(\"/dev/filemon\", O_RDWR)");
                if ((fm_log = open(fmfname,
                    O_WRONLY | O_CREAT | O_TRUNC | O_CLOEXEC,
                    S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH)) == -1)
                        err(1, "open(%s)", fmfname);
                if (ioctl(fm_fd, FILEMON_SET_FD, &fm_log) < 0)
                        err(1, "Cannot set filemon log file descriptor");
        }

        if (pflg)
                playback(fscript);

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

        if (rawout)
                record(fscript, NULL, 0, 's');

        if (!qflg) {
                tvec = time(NULL);
                (void)printf("Script started, output file is %s\n", fname);
                if (!rawout) {
                        (void)fprintf(fscript, "Script started on %s",
                            ctime(&tvec));
                        if (argv[0]) {
                                showexit = 1;
                                fprintf(fscript, "Command: ");
                                for (k = 0 ; argv[k] ; ++k)
                                        fprintf(fscript, "%s%s", k ? " " : "",
                                                argv[k]);
                                fprintf(fscript, "\n");
                        }
                }
                fflush(fscript);
                if (fflg) {
                        (void)printf("Filemon started, output file is %s\n",
                            fmfname);
                }
        }
        if (ttyflg) {
                rtt = tt;
                cfmakeraw(&rtt);
                rtt.c_lflag &= ~ECHO;
                (void)tcsetattr(STDIN_FILENO, TCSAFLUSH, &rtt);
        }

        assert(fflg ? fm_fd >= 0 : fm_fd < 0);

        child = fork();
        if (child < 0) {
                warn("fork");
                done(1);
        }
        if (child == 0) {
                if (fflg) {
                        int pid;

                        pid = getpid();
                        if (ioctl(fm_fd, FILEMON_SET_PID, &pid) < 0)
                                err(1, "Cannot set filemon PID");
                }

                doshell(argv);
        }
        close(slave);

        if (wflg) {
                struct sigaction sa = { .sa_handler = resizeit };
                sigset_t smask;

                sigaction(SIGWINCH, &sa, NULL);

                sigemptyset(&smask);
                sigaddset(&smask, SIGWINCH);

                if (sigprocmask(SIG_BLOCK, &smask, &selmask) != 0)
                        err(1, "Failed to block SIGWINCH");

                /* Just in case SIGWINCH was blocked before we came in. */
                sigdelset(&selmask, SIGWINCH);
                pselmask = &selmask;
        }

        start = tvec = time(0);
        readstdin = 1;
        for (;;) {
                FD_ZERO(&rfd);
                FD_ZERO(&wfd);
                FD_SET(master, &rfd);
                if (readstdin)
                        FD_SET(STDIN_FILENO, &rfd);
                if (!TAILQ_EMPTY(&obuf_list))
                        FD_SET(master, &wfd);
                if (!readstdin && ttyflg) {
                        tv.tv_sec = 1;
                        tv.tv_nsec = 0;
                        tvp = &tv;
                        readstdin = 1;
                } else if (flushtime > 0) {
                        tv.tv_sec = flushtime - (tvec - start);
                        tv.tv_nsec = 0;
                        tvp = &tv;
                } else {
                        tvp = NULL;
                }
                n = pselect(master + 1, &rfd, &wfd, NULL, tvp, pselmask);
                if (n < 0 && errno != EINTR)
                        break;

                if (doresize) {
                        if (ioctl(STDIN_FILENO, TIOCGWINSZ, &win) != -1)
                                ioctl(master, TIOCSWINSZ, &win);
                        doresize = 0;
                }

                if (n > 0 && FD_ISSET(STDIN_FILENO, &rfd)) {
                        cc = read(STDIN_FILENO, ibuf, BUFSIZ);
                        if (cc < 0)
                                break;
                        if (cc == 0) {
                                if (tcgetattr(master, &stt) == 0 &&
                                    (stt.c_lflag & ICANON) != 0) {
                                        (void)write(master, &stt.c_cc[VEOF], 1);
                                }
                                readstdin = 0;
                        }
                        if (cc > 0) {
                                if (rawout)
                                        record(fscript, ibuf, cc, 'i');
                                be = malloc(sizeof(*be) + cc);
                                be->rpos = 0;
                                be->len = cc;
                                memcpy(be->ibuf, ibuf, cc);
                                TAILQ_INSERT_TAIL(&obuf_list, be, link);
                        }
                }
                if (n > 0 && FD_ISSET(master, &wfd)) {
                        while ((be = TAILQ_FIRST(&obuf_list)) != NULL) {
                                cc = write(master, be->ibuf + be->rpos,
                                    be->len);
                                if (cc == -1) {
                                        if (errno == EWOULDBLOCK ||
                                            errno == EINTR)
                                                break;
                                        warn("write master");
                                        done(1);
                                }
                                if (cc == 0)
                                        break;          /* retry later ? */
                                if (kflg && tcgetattr(master, &stt) >= 0 &&
                                    ((stt.c_lflag & ECHO) == 0)) {
                                        (void)fwrite(be->ibuf + be->rpos,
                                            1, cc, fscript);
                                }
                                be->len -= cc;
                                if (be->len == 0) {
                                        TAILQ_REMOVE(&obuf_list, be, link);
                                        free(be);
                                } else {
                                        be->rpos += cc;
                                }
                        }
                }
                if (n > 0 && FD_ISSET(master, &rfd)) {
                        cc = read(master, obuf, sizeof(obuf));
                        if (cc <= 0)
                                break;
                        (void)write(STDOUT_FILENO, obuf, cc);
                        if (rawout)
                                record(fscript, obuf, cc, 'o');
                        else
                                (void)fwrite(obuf, 1, cc, fscript);
                }
                tvec = time(0);
                if (tvec - start >= flushtime) {
                        fflush(fscript);
                        start = tvec;
                }
                if (Fflg)
                        fflush(fscript);
        }
        finish();
        done(0);
}

static void
usage(void)
{
        (void)fprintf(stderr,
            "usage: script [-aeFfkpqrw] [-t time] [file [command ...]]\n");
        (void)fprintf(stderr,
            "       script -p [-deq] [-T fmt] [file]\n");
        exit(1);
}

static void
finish(void)
{
        int e, status;

        if (waitpid(child, &status, 0) == child) {
                if (WIFEXITED(status))
                        e = WEXITSTATUS(status);
                else if (WIFSIGNALED(status))
                        e = WTERMSIG(status);
                else /* can't happen */
                        e = 1;
                done(e);
        }
}

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

        shell = getenv("SHELL");
        if (shell == NULL)
                shell = _PATH_BSHELL;

        (void)close(master);
        (void)fclose(fscript);
        free(fmfname);
        login_tty(slave);
        setenv("SCRIPT", fname, 1);
        if (av[0]) {
                execvp(av[0], av);
                warn("%s", av[0]);
        } else {
                execl(shell, shell, "-i", (char *)NULL);
                warn("%s", shell);
        }
        exit(1);
}

static void
done(int eno)
{
        time_t tvec;

        if (ttyflg)
                (void)tcsetattr(STDIN_FILENO, TCSAFLUSH, &tt);
        tvec = time(NULL);
        if (rawout)
                record(fscript, NULL, 0, 'e');
        if (!qflg) {
                if (!rawout) {
                        if (showexit)
                                (void)fprintf(fscript, "\nCommand exit status:"
                                    " %d", eno);
                        (void)fprintf(fscript, "\nScript done on %s",
                            ctime(&tvec));
                }
                (void)printf("\nScript done, output file is %s\n", fname);
                if (fflg) {
                        (void)printf("Filemon done, output file is %s\n",
                            fmfname);
                }
        }
        (void)fclose(fscript);
        (void)close(master);
        exit(eno);
}

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(1, "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(1, NULL);
        } else {
                while (len > 0) {
                        l = MIN(DEF_BUF, len);
                        if (fread(buf, sizeof(char), l, fp) != l)
                                err(1, "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(1, "tcgetattr");
                return;
        }
        ttyflg = 1;
        traw = tt;
        cfmakeraw(&traw);
        traw.c_lflag |= ISIG;
        (void)tcsetattr(STDOUT_FILENO, TCSANOW, &traw);
}

static void
termreset(void)
{
        if (ttyflg) {
                tcsetattr(STDOUT_FILENO, TCSADRAIN, &tt);
                ttyflg = 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;
        time_t lclock;
        int reg;

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

        reg = S_ISREG(pst.st_mode);
        lclock = 0;

        for (nread = 0; !reg || nread < pst.st_size; nread += save_len) {
                if (fread(&stamp, sizeof(stamp), 1, fp) != 1) {
                        if (reg)
                                err(1, "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(1, "invalid stamp");

                save_len += stamp.scr_len;
                tclock = stamp.scr_sec;
                tso.tv_sec = stamp.scr_sec;
                tso.tv_nsec = stamp.scr_usec * 1000;
                if (nread == 0)
                        tsi = tso;

                switch (stamp.scr_direction) {
                case 's':
                        if (!qflg)
                            (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 (!qflg)
                                (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':
                        if (tflg) {
                                if (stamp.scr_len == 0)
                                        continue;
                                if (tclock - lclock > 0) {
                                    l = strftime(buf, sizeof buf, tstamp_fmt,
                                        localtime(&tclock));
                                    (void)write(STDOUT_FILENO, buf, l);
                                }
                                lclock = tclock;
                        } else {
                                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(1, "cannot read buffer");

                                (void)write(STDOUT_FILENO, buf, l);
                                stamp.scr_len -= l;
                        }
                        break;
                default:
                        errx(1, "invalid direction");
                }
        }
        (void)fclose(fp);
        exit(0);
}

static void
resizeit(int signo __unused)
{
        doresize = 1;
}