mirror of
https://github.com/sheumann/hush.git
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186 lines
4.8 KiB
C
186 lines
4.8 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* script implementation for busybox
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*
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* pascal.bellard@ads-lu.com
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*
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* Based on code from util-linux v 2.12r
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* Copyright (c) 1980
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* The Regents of the University of California. All rights reserved.
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*
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* Licensed under GPLv2 or later, see file License in this tarball for details.
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*/
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#include "libbb.h"
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static smallint fd_count = 2;
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static void handle_sigchld(int sig ATTRIBUTE_UNUSED)
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{
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fd_count = 0;
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}
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int script_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int script_main(int argc ATTRIBUTE_UNUSED, char **argv)
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{
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int opt;
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int mode;
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int child_pid;
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int attr_ok; /* NB: 0: ok */
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int winsz_ok;
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int pty;
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char pty_line[GETPTY_BUFSIZE];
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struct termios tt, rtt;
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struct winsize win;
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const char *fname = "typescript";
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const char *shell;
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char shell_opt[] = "-i";
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char *shell_arg = NULL;
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#if ENABLE_GETOPT_LONG
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static const char getopt_longopts[] ALIGN1 =
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"append\0" No_argument "a"
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"command\0" Required_argument "c"
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"flush\0" No_argument "f"
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"quiet\0" No_argument "q"
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;
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applet_long_options = getopt_longopts;
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#endif
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opt_complementary = "?1"; /* max one arg */
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opt = getopt32(argv, "ac:fq", &shell_arg);
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//argc -= optind;
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argv += optind;
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if (argv[0]) {
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fname = argv[0];
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}
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mode = O_CREAT|O_TRUNC|O_WRONLY;
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if (opt & 1) {
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mode = O_CREAT|O_APPEND|O_WRONLY;
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}
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if (opt & 2) {
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shell_opt[1] = 'c';
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}
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if (!(opt & 8)) { /* not -q */
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printf("Script started, file is %s\n", fname);
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}
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shell = getenv("SHELL");
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if (shell == NULL) {
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shell = DEFAULT_SHELL;
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}
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pty = xgetpty(pty_line);
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/* get current stdin's tty params */
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attr_ok = tcgetattr(0, &tt);
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winsz_ok = ioctl(0, TIOCGWINSZ, (char *)&win);
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rtt = tt;
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cfmakeraw(&rtt);
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rtt.c_lflag &= ~ECHO;
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tcsetattr(0, TCSAFLUSH, &rtt);
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/* "script" from util-linux exits when child exits,
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* we wouldn't wait for EOF from slave pty
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* (output may be produced by grandchildren of child) */
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signal(SIGCHLD, handle_sigchld);
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/* TODO: SIGWINCH? pass window size changes down to slave? */
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child_pid = vfork();
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if (child_pid < 0) {
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bb_perror_msg_and_die("vfork");
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}
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if (child_pid) {
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/* parent */
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#define buf bb_common_bufsiz1
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struct pollfd pfd[2];
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int outfd, count, loop;
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outfd = xopen(fname, mode);
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pfd[0].fd = pty;
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pfd[0].events = POLLIN;
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pfd[1].fd = 0;
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pfd[1].events = POLLIN;
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ndelay_on(pty); /* this descriptor is not shared, can do this */
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/* ndelay_on(0); - NO, stdin can be shared! Pity :( */
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/* copy stdin to pty master input,
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* copy pty master output to stdout and file */
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/* TODO: don't use full_write's, use proper write buffering */
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while (fd_count) {
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/* not safe_poll! we want SIGCHLD to EINTR poll */
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if (poll(pfd, fd_count, -1) < 0 && errno != EINTR) {
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/* If child exits too quickly, we may get EIO:
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* for example, try "script -c true" */
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break;
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}
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if (pfd[0].revents) {
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errno = 0;
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count = safe_read(pty, buf, sizeof(buf));
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if (count <= 0 && errno != EAGAIN) {
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/* err/eof from pty: exit */
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goto restore;
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}
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if (count > 0) {
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full_write(STDOUT_FILENO, buf, count);
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full_write(outfd, buf, count);
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if (opt & 4) { /* -f */
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fsync(outfd);
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}
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}
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}
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if (pfd[1].revents) {
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count = safe_read(STDIN_FILENO, buf, sizeof(buf));
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if (count <= 0) {
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/* err/eof from stdin: don't read stdin anymore */
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pfd[1].revents = 0;
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fd_count--;
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} else {
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full_write(pty, buf, count);
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}
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}
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}
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/* If loop was exited because SIGCHLD handler set fd_count to 0,
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* there still can be some buffered output. But not loop forever:
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* we won't pump orphaned grandchildren's output indefinitely.
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* Testcase: running this in script:
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* exec dd if=/dev/zero bs=1M count=1
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* must have "1+0 records in, 1+0 records out" captured too.
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* (util-linux's script doesn't do this. buggy :) */
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loop = 999;
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/* pty is in O_NONBLOCK mode, we exit as soon as buffer is empty */
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while (--loop && (count = safe_read(pty, buf, sizeof(buf))) > 0) {
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full_write(STDOUT_FILENO, buf, count);
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full_write(outfd, buf, count);
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}
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restore:
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if (attr_ok == 0)
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tcsetattr(0, TCSAFLUSH, &tt);
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if (!(opt & 8)) /* not -q */
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printf("Script done, file is %s\n", fname);
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return EXIT_SUCCESS;
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}
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/* child: make pty slave to be input, output, error; run shell */
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close(pty); /* close pty master */
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/* open pty slave to fd 0,1,2 */
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close(0);
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xopen(pty_line, O_RDWR); /* uses fd 0 */
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xdup2(0, 1);
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xdup2(0, 2);
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/* copy our original stdin tty's parameters to pty */
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if (attr_ok == 0)
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tcsetattr(0, TCSAFLUSH, &tt);
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if (winsz_ok == 0)
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ioctl(0, TIOCSWINSZ, (char *)&win);
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/* set pty as a controlling tty */
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setsid();
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ioctl(0, TIOCSCTTY, 0 /* 0: don't forcibly steal */);
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/* signal(SIGCHLD, SIG_DFL); - exec does this for us */
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execl(shell, shell, shell_opt, shell_arg, NULL);
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bb_simple_perror_msg_and_die(shell);
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}
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