busybox/util-linux/script.c
Denys Vlasenko 4dea1edd08 script: -f means "flush", not "fsync"
function                                             old     new   delta
packed_usage                                       31765   31768      +3
script_main                                         1102    1082     -20

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2017-08-07 02:21:34 +02:00

241 lines
6.6 KiB
C

/* 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.
*/
//config:config SCRIPT
//config: bool "script (8 kb)"
//config: default y
//config: help
//config: The script makes typescript of terminal session.
//applet:IF_SCRIPT(APPLET(script, BB_DIR_USR_BIN, BB_SUID_DROP))
//kbuild:lib-$(CONFIG_SCRIPT) += script.o
//usage:#define script_trivial_usage
//usage: "[-afq] [-t[FILE]] [-c PROG] [OUTFILE]"
//usage:#define script_full_usage "\n\n"
//usage: "Default OUTFILE is 'typescript'"
//usage: "\n"
//usage: "\n -a Append output"
//usage: "\n -c PROG Run PROG, not shell"
/* Accepted but has no effect (we never buffer output) */
/*//usage: "\n -f Flush output after each write"*/
//usage: "\n -q Quiet"
//usage: "\n -t[FILE] Send timing to stderr or FILE"
//util-linux-2.28:
//-e: return exit code of the child
//FYI (reported as bbox bug #2749):
// > script -q -c 'echo -e -n "1\n2\n3\n"' /dev/null </dev/null >123.txt
// > The output file on full-blown ubuntu system contains 6 bytes.
// > Output on Busybox system (arm-linux) contains extra '\r' byte in each line.
//however, in my test, "script" from util-linux-2.28 seems to also add '\r' bytes.
#include "libbb.h"
#include "common_bufsiz.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;
FILE *timing_fp;
const char *str_t = NULL;
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"
"timing\0" Optional_argument "t"
;
applet_long_options = getopt_longopts;
#endif
opt_complementary = "?1"; /* max one arg */
opt = getopt32(argv, "ac:fqt::", &shell_arg, &str_t);
//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);
}
timing_fp = stderr;
if (str_t) {
timing_fp = xfopen_for_write(str_t);
}
shell = get_shell_name();
/* Some people run "script ... 0>&-".
* Our code assumes that STDIN_FILENO != pty.
* Ensure STDIN_FILENO is not closed:
*/
bb_sanitize_stdio();
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 */
struct pollfd pfd[2];
int outfd, count, loop;
double oldtime = time(NULL);
smallint fd_count = 2;
#define buf bb_common_bufsiz1
setup_common_bufsiz();
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, COMMON_BUFSIZE);
if (count <= 0 && errno != EAGAIN) {
/* err/eof from pty: exit */
goto restore;
}
if (count > 0) {
if (opt & OPT_t) {
struct timeval tv;
double newtime;
gettimeofday(&tv, NULL);
newtime = tv.tv_sec + (double) tv.tv_usec / 1000000;
fprintf(timing_fp, "%f %u\n", newtime - oldtime, count);
oldtime = newtime;
}
full_write(STDOUT_FILENO, buf, count);
full_write(outfd, buf, count);
// If we'd be using (buffered) FILE i/o, we'd need this:
//if (opt & OPT_f) {
// fflush(outfd);
//}
}
}
if (pfd[1].revents) {
count = safe_read(STDIN_FILENO, buf, COMMON_BUFSIZE);
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, COMMON_BUFSIZE)) > 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);
}