ba90b065dcd3dcc250b9677bb82a43e3badc7e01
[platform/upstream/busybox.git] / util-linux / script.c
1 /* vi: set sw=4 ts=4: */
2 /*
3  * script implementation for busybox
4  *
5  * pascal.bellard@ads-lu.com
6  *
7  * Based on code from util-linux v 2.12r
8  * Copyright (c) 1980
9  *      The Regents of the University of California.  All rights reserved.
10  *
11  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
12  */
13 #include "libbb.h"
14
15 int script_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
16 int script_main(int argc UNUSED_PARAM, char **argv)
17 {
18         int opt;
19         int mode;
20         int child_pid;
21         int attr_ok; /* NB: 0: ok */
22         int winsz_ok;
23         int pty;
24         char pty_line[GETPTY_BUFSIZE];
25         struct termios tt, rtt;
26         struct winsize win;
27         const char *fname = "typescript";
28         const char *shell;
29         char shell_opt[] = "-i";
30         char *shell_arg = NULL;
31         enum {
32                 OPT_a = (1 << 0),
33                 OPT_c = (1 << 1),
34                 OPT_f = (1 << 2),
35                 OPT_q = (1 << 3),
36                 OPT_t = (1 << 4),
37         };
38
39 #if ENABLE_LONG_OPTS
40         static const char getopt_longopts[] ALIGN1 =
41                 "append\0"  No_argument       "a"
42                 "command\0" Required_argument "c"
43                 "flush\0"   No_argument       "f"
44                 "quiet\0"   No_argument       "q"
45                 IF_SCRIPTREPLAY("timing\0" No_argument "t")
46                 ;
47
48         applet_long_options = getopt_longopts;
49 #endif
50
51         opt_complementary = "?1"; /* max one arg */
52         opt = getopt32(argv, "ac:fq" IF_SCRIPTREPLAY("t") , &shell_arg);
53         //argc -= optind;
54         argv += optind;
55         if (argv[0]) {
56                 fname = argv[0];
57         }
58         mode = O_CREAT|O_TRUNC|O_WRONLY;
59         if (opt & OPT_a) {
60                 mode = O_CREAT|O_APPEND|O_WRONLY;
61         }
62         if (opt & OPT_c) {
63                 shell_opt[1] = 'c';
64         }
65         if (!(opt & OPT_q)) {
66                 printf("Script started, file is %s\n", fname);
67         }
68         shell = getenv("SHELL");
69         if (shell == NULL) {
70                 shell = DEFAULT_SHELL;
71         }
72
73         pty = xgetpty(pty_line);
74
75         /* get current stdin's tty params */
76         attr_ok = tcgetattr(0, &tt);
77         winsz_ok = ioctl(0, TIOCGWINSZ, (char *)&win);
78
79         rtt = tt;
80         cfmakeraw(&rtt);
81         rtt.c_lflag &= ~ECHO;
82         tcsetattr(0, TCSAFLUSH, &rtt);
83
84         /* "script" from util-linux exits when child exits,
85          * we wouldn't wait for EOF from slave pty
86          * (output may be produced by grandchildren of child) */
87         signal(SIGCHLD, record_signo);
88
89         /* TODO: SIGWINCH? pass window size changes down to slave? */
90
91         child_pid = xvfork();
92
93         if (child_pid) {
94                 /* parent */
95 #define buf bb_common_bufsiz1
96                 struct pollfd pfd[2];
97                 int outfd, count, loop;
98                 double oldtime = ENABLE_SCRIPTREPLAY ? time(NULL) : 0;
99                 smallint fd_count = 2;
100
101                 outfd = xopen(fname, mode);
102                 pfd[0].fd = pty;
103                 pfd[0].events = POLLIN;
104                 pfd[1].fd = STDIN_FILENO;
105                 pfd[1].events = POLLIN;
106                 ndelay_on(pty); /* this descriptor is not shared, can do this */
107                 /* ndelay_on(STDIN_FILENO); - NO, stdin can be shared! Pity :( */
108
109                 /* copy stdin to pty master input,
110                  * copy pty master output to stdout and file */
111                 /* TODO: don't use full_write's, use proper write buffering */
112                 while (fd_count && !bb_got_signal) {
113                         /* not safe_poll! we want SIGCHLD to EINTR poll */
114                         if (poll(pfd, fd_count, -1) < 0 && errno != EINTR) {
115                                 /* If child exits too quickly, we may get EIO:
116                                  * for example, try "script -c true" */
117                                 break;
118                         }
119                         if (pfd[0].revents) {
120                                 errno = 0;
121                                 count = safe_read(pty, buf, sizeof(buf));
122                                 if (count <= 0 && errno != EAGAIN) {
123                                         /* err/eof from pty: exit */
124                                         goto restore;
125                                 }
126                                 if (count > 0) {
127                                         if (ENABLE_SCRIPTREPLAY && (opt & OPT_t)) {
128                                                 struct timeval tv;
129                                                 double newtime;
130
131                                                 gettimeofday(&tv, NULL);
132                                                 newtime = tv.tv_sec + (double) tv.tv_usec / 1000000;
133                                                 fprintf(stderr, "%f %u\n", newtime - oldtime, count);
134                                                 oldtime = newtime;
135                                         }
136                                         full_write(STDOUT_FILENO, buf, count);
137                                         full_write(outfd, buf, count);
138                                         if (opt & OPT_f) {
139                                                 fsync(outfd);
140                                         }
141                                 }
142                         }
143                         if (pfd[1].revents) {
144                                 count = safe_read(STDIN_FILENO, buf, sizeof(buf));
145                                 if (count <= 0) {
146                                         /* err/eof from stdin: don't read stdin anymore */
147                                         pfd[1].revents = 0;
148                                         fd_count--;
149                                 } else {
150                                         full_write(pty, buf, count);
151                                 }
152                         }
153                 }
154                 /* If loop was exited because SIGCHLD handler set bb_got_signal,
155                  * there still can be some buffered output. But dont loop forever:
156                  * we won't pump orphaned grandchildren's output indefinitely.
157                  * Testcase: running this in script:
158                  *      exec dd if=/dev/zero bs=1M count=1
159                  * must have "1+0 records in, 1+0 records out" captured too.
160                  * (util-linux's script doesn't do this. buggy :) */
161                 loop = 999;
162                 /* pty is in O_NONBLOCK mode, we exit as soon as buffer is empty */
163                 while (--loop && (count = safe_read(pty, buf, sizeof(buf))) > 0) {
164                         full_write(STDOUT_FILENO, buf, count);
165                         full_write(outfd, buf, count);
166                 }
167  restore:
168                 if (attr_ok == 0)
169                         tcsetattr(0, TCSAFLUSH, &tt);
170                 if (!(opt & OPT_q))
171                         printf("Script done, file is %s\n", fname);
172                 return EXIT_SUCCESS;
173         }
174
175         /* child: make pty slave to be input, output, error; run shell */
176         close(pty); /* close pty master */
177         /* open pty slave to fd 0,1,2 */
178         close(0);
179         xopen(pty_line, O_RDWR); /* uses fd 0 */
180         xdup2(0, 1);
181         xdup2(0, 2);
182         /* copy our original stdin tty's parameters to pty */
183         if (attr_ok == 0)
184                 tcsetattr(0, TCSAFLUSH, &tt);
185         if (winsz_ok == 0)
186                 ioctl(0, TIOCSWINSZ, (char *)&win);
187         /* set pty as a controlling tty */
188         setsid();
189         ioctl(0, TIOCSCTTY, 0 /* 0: don't forcibly steal */);
190
191         /* Non-ignored signals revert to SIG_DFL on exec anyway */
192         /*signal(SIGCHLD, SIG_DFL);*/
193         execl(shell, shell, shell_opt, shell_arg, (char *) NULL);
194         bb_simple_perror_msg_and_die(shell);
195 }