source: MondoRescue/branches/3.2/mindi-busybox/util-linux/script.c@ 3232

/* vi: set sw=4 ts=4: */
/*
 * script implementation for busybox
 *
 * pascal.bellard@ads-lu.com
 *
 * Based on code from util-linux v 2.12r
 * Copyright (c) 1980
 * The Regents of the University of California.  All rights reserved.
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 */

//usage:#define script_trivial_usage
//usage:       "[-afq" IF_SCRIPTREPLAY("t") "] [-c PROG] [OUTFILE]"
//usage:#define script_full_usage "\n\n"
//usage:       "    -a  Append output"
//usage:     "\n    -c PROG Run PROG, not shell"
//usage:     "\n    -f  Flush output after each write"
//usage:     "\n    -q  Quiet"
//usage:    IF_SCRIPTREPLAY(
//usage:     "\n    -t  Send timing to stderr"
//usage:    )

#include "libbb.h"

int script_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int script_main(int argc UNUSED_PARAM, char **argv)
{
    int opt;
    int mode;
    int child_pid;
    int attr_ok; /* NB: 0: ok */
    int winsz_ok;
    int pty;
    char pty_line[GETPTY_BUFSIZE];
    struct termios tt, rtt;
    struct winsize win;
    const char *fname = "typescript";
    const char *shell;
    char shell_opt[] = "-i";
    char *shell_arg = NULL;
    enum {
        OPT_a = (1 << 0),
        OPT_c = (1 << 1),
        OPT_f = (1 << 2),
        OPT_q = (1 << 3),
        OPT_t = (1 << 4),
    };

#if ENABLE_LONG_OPTS
    static const char getopt_longopts[] ALIGN1 =
        "append\0"  No_argument       "a"
        "command\0" Required_argument "c"
        "flush\0"   No_argument       "f"
        "quiet\0"   No_argument       "q"
        IF_SCRIPTREPLAY("timing\0" No_argument "t")
        ;

    applet_long_options = getopt_longopts;
#endif

    opt_complementary = "?1"; /* max one arg */
    opt = getopt32(argv, "ac:fq" IF_SCRIPTREPLAY("t") , &shell_arg);
    //argc -= optind;
    argv += optind;
    if (argv[0]) {
        fname = argv[0];
    }
    mode = O_CREAT|O_TRUNC|O_WRONLY;
    if (opt & OPT_a) {
        mode = O_CREAT|O_APPEND|O_WRONLY;
    }
    if (opt & OPT_c) {
        shell_opt[1] = 'c';
    }
    if (!(opt & OPT_q)) {
        printf("Script started, file is %s\n", fname);
    }
    shell = get_shell_name();

    pty = xgetpty(pty_line);

    /* get current stdin's tty params */
    attr_ok = tcgetattr(0, &tt);
    winsz_ok = ioctl(0, TIOCGWINSZ, (char *)&win);

    rtt = tt;
    cfmakeraw(&rtt);
    rtt.c_lflag &= ~ECHO;
    tcsetattr(0, TCSAFLUSH, &rtt);

    /* "script" from util-linux exits when child exits,
     * we wouldn't wait for EOF from slave pty
     * (output may be produced by grandchildren of child) */
    signal(SIGCHLD, record_signo);

    /* TODO: SIGWINCH? pass window size changes down to slave? */

    child_pid = xvfork();

    if (child_pid) {
        /* parent */
#define buf bb_common_bufsiz1
        struct pollfd pfd[2];
        int outfd, count, loop;
        double oldtime = ENABLE_SCRIPTREPLAY ? time(NULL) : 0;
        smallint fd_count = 2;

        outfd = xopen(fname, mode);
        pfd[0].fd = pty;
        pfd[0].events = POLLIN;
        pfd[1].fd = STDIN_FILENO;
        pfd[1].events = POLLIN;
        ndelay_on(pty); /* this descriptor is not shared, can do this */
        /* ndelay_on(STDIN_FILENO); - NO, stdin can be shared! Pity :( */

        /* copy stdin to pty master input,
         * copy pty master output to stdout and file */
        /* TODO: don't use full_write's, use proper write buffering */
        while (fd_count && !bb_got_signal) {
            /* not safe_poll! we want SIGCHLD to EINTR poll */
            if (poll(pfd, fd_count, -1) < 0 && errno != EINTR) {
                /* If child exits too quickly, we may get EIO:
                 * for example, try "script -c true" */
                break;
            }
            if (pfd[0].revents) {
                errno = 0;
                count = safe_read(pty, buf, sizeof(buf));
                if (count <= 0 && errno != EAGAIN) {
                    /* err/eof from pty: exit */
                    goto restore;
                }
                if (count > 0) {
                    if (ENABLE_SCRIPTREPLAY && (opt & OPT_t)) {
                        struct timeval tv;
                        double newtime;

                        gettimeofday(&tv, NULL);
                        newtime = tv.tv_sec + (double) tv.tv_usec / 1000000;
                        fprintf(stderr, "%f %u\n", newtime - oldtime, count);
                        oldtime = newtime;
                    }
                    full_write(STDOUT_FILENO, buf, count);
                    full_write(outfd, buf, count);
                    if (opt & OPT_f) {
                        fsync(outfd);
                    }
                }
            }
            if (pfd[1].revents) {
                count = safe_read(STDIN_FILENO, buf, sizeof(buf));
                if (count <= 0) {
                    /* err/eof from stdin: don't read stdin anymore */
                    pfd[1].revents = 0;
                    fd_count--;
                } else {
                    full_write(pty, buf, count);
                }
            }
        }
        /* If loop was exited because SIGCHLD handler set bb_got_signal,
         * there still can be some buffered output. But dont loop forever:
         * we won't pump orphaned grandchildren's output indefinitely.
         * Testcase: running this in script:
         *      exec dd if=/dev/zero bs=1M count=1
         * must have "1+0 records in, 1+0 records out" captured too.
         * (util-linux's script doesn't do this. buggy :) */
        loop = 999;
        /* pty is in O_NONBLOCK mode, we exit as soon as buffer is empty */
        while (--loop && (count = safe_read(pty, buf, sizeof(buf))) > 0) {
            full_write(STDOUT_FILENO, buf, count);
            full_write(outfd, buf, count);
        }
 restore:
        if (attr_ok == 0)
            tcsetattr(0, TCSAFLUSH, &tt);
        if (!(opt & OPT_q))
            printf("Script done, file is %s\n", fname);
        return EXIT_SUCCESS;
    }

    /* child: make pty slave to be input, output, error; run shell */
    close(pty); /* close pty master */
    /* open pty slave to fd 0,1,2 */
    close(0);
    xopen(pty_line, O_RDWR); /* uses fd 0 */
    xdup2(0, 1);
    xdup2(0, 2);
    /* copy our original stdin tty's parameters to pty */
    if (attr_ok == 0)
        tcsetattr(0, TCSAFLUSH, &tt);
    if (winsz_ok == 0)
        ioctl(0, TIOCSWINSZ, (char *)&win);
    /* set pty as a controlling tty */
    setsid();
    ioctl(0, TIOCSCTTY, 0 /* 0: don't forcibly steal */);

    /* Non-ignored signals revert to SIG_DFL on exec anyway */
    /*signal(SIGCHLD, SIG_DFL);*/
    execl(shell, shell, shell_opt, shell_arg, (char *) NULL);
    bb_simple_perror_msg_and_die(shell);
}