aboutsummaryrefslogtreecommitdiff
path: root/util-linux/script.c
blob: d16a2914a901567c855c0eb223c67d54fda9fa3f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
/* 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"

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),
#if ENABLE_SCRIPTREPLAY
		OPT_t = (1 << 4),
#endif
	};

#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"
# if ENABLE_SCRIPTREPLAY
		"timing\0"  No_argument       "t"
# endif
		;

	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 = 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, record_signo);

	/* 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;
#if ENABLE_SCRIPTREPLAY
		double oldtime = time(NULL);
#endif
		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
					if (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;
					}
#endif
					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);
}