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/* 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 tarball for details.
*/
#include "libbb.h"
static smallint fd_count = 2;
static void handle_sigchld(int sig ATTRIBUTE_UNUSED)
{
fd_count = 0;
}
int script_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int script_main(int argc ATTRIBUTE_UNUSED, 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;
#if ENABLE_GETOPT_LONG
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"
;
applet_long_options = getopt_longopts;
#endif
opt_complementary = "?1"; /* max one arg */
opt = getopt32(argv, "ac:fq", &shell_arg);
//argc -= optind;
argv += optind;
if (argv[0]) {
fname = argv[0];
}
mode = O_CREAT|O_TRUNC|O_WRONLY;
if (opt & 1) {
mode = O_CREAT|O_APPEND|O_WRONLY;
}
if (opt & 2) {
shell_opt[1] = 'c';
}
if (!(opt & 8)) { /* not -q */
printf("Script started, file is %s\n", fname);
}
shell = getenv("SHELL");
if (shell == NULL) {
shell = DEFAULT_SHELL;
}
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, handle_sigchld);
/* TODO: SIGWINCH? pass window size changes down to slave? */
child_pid = vfork();
if (child_pid < 0) {
bb_perror_msg_and_die("vfork");
}
if (child_pid) {
/* parent */
#define buf bb_common_bufsiz1
struct pollfd pfd[2];
int outfd, count, loop;
outfd = xopen(fname, mode);
pfd[0].fd = pty;
pfd[0].events = POLLIN;
pfd[1].fd = 0;
pfd[1].events = POLLIN;
ndelay_on(pty); /* this descriptor is not shared, can do this */
/* ndelay_on(0); - 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) {
/* 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) {
full_write(1, buf, count);
full_write(outfd, buf, count);
if (opt & 4) { /* -f */
fsync(outfd);
}
}
}
if (pfd[1].revents) {
count = safe_read(0, 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 fd_count to 0,
* there still can be some buffered output. But not 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(1, buf, count);
full_write(outfd, buf, count);
}
restore:
if (attr_ok == 0)
tcsetattr(0, TCSAFLUSH, &tt);
if (!(opt & 8)) /* not -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 */);
/* signal(SIGCHLD, SIG_DFL); - exec does this for us */
execl(shell, shell, shell_opt, shell_arg, NULL);
bb_simple_perror_msg_and_die(shell);
}
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