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 source tree.
  12  */
  13
  14 //usage:#define script_trivial_usage
  15 //usage:       "[-afq" IF_SCRIPTREPLAY("t") "] [-c PROG] [OUTFILE]"
  16 //usage:#define script_full_usage "\n\n"
  17 //usage:       "        -a      Append output"
  18 //usage:     "\n        -c PROG Run PROG, not shell"
  19 //usage:     "\n        -f      Flush output after each write"
  20 //usage:     "\n        -q      Quiet"
  21 //usage:        IF_SCRIPTREPLAY(
  22 //usage:     "\n        -t      Send timing to stderr"
  23 //usage:        )
  24
  25 #include "libbb.h"
  26
  27 int script_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  28 int script_main(int argc UNUSED_PARAM, char **argv)
  29 {
  30         int opt;
  31         int mode;
  32         int child_pid;
  33         int attr_ok; /* NB: 0: ok */
  34         int winsz_ok;
  35         int pty;
  36         char pty_line[GETPTY_BUFSIZE];
  37         struct termios tt, rtt;
  38         struct winsize win;
  39         const char *fname = "typescript";
  40         const char *shell;
  41         char shell_opt[] = "-i";
  42         char *shell_arg = NULL;
  43         enum {
  44                 OPT_a = (1 << 0),
  45                 OPT_c = (1 << 1),
  46                 OPT_f = (1 << 2),
  47                 OPT_q = (1 << 3),
  48                 OPT_t = (1 << 4),
  49         };
  50
  51 #if ENABLE_LONG_OPTS
  52         static const char getopt_longopts[] ALIGN1 =
  53                 "append\0"  No_argument       "a"
  54                 "command\0" Required_argument "c"
  55                 "flush\0"   No_argument       "f"
  56                 "quiet\0"   No_argument       "q"
  57                 IF_SCRIPTREPLAY("timing\0" No_argument "t")
  58                 ;
  59
  60         applet_long_options = getopt_longopts;
  61 #endif
  62
  63         opt_complementary = "?1"; /* max one arg */
  64         opt = getopt32(argv, "ac:fq" IF_SCRIPTREPLAY("t") , &shell_arg);
  65         //argc -= optind;
  66         argv += optind;
  67         if (argv[0]) {
  68                 fname = argv[0];
  69         }
  70         mode = O_CREAT|O_TRUNC|O_WRONLY;
  71         if (opt & OPT_a) {
  72                 mode = O_CREAT|O_APPEND|O_WRONLY;
  73         }
  74         if (opt & OPT_c) {
  75                 shell_opt[1] = 'c';
  76         }
  77         if (!(opt & OPT_q)) {
  78                 printf("Script started, file is %s\n", fname);
  79         }
  80         shell = get_shell_name();
  81
  82         pty = xgetpty(pty_line);
  83
  84         /* get current stdin's tty params */
  85         attr_ok = tcgetattr(0, &tt);
  86         winsz_ok = ioctl(0, TIOCGWINSZ, (char *)&win);
  87
  88         rtt = tt;
  89         cfmakeraw(&rtt);
  90         rtt.c_lflag &= ~ECHO;
  91         tcsetattr(0, TCSAFLUSH, &rtt);
  92
  93         /* "script" from util-linux exits when child exits,
  94          * we wouldn't wait for EOF from slave pty
  95          * (output may be produced by grandchildren of child) */
  96         signal(SIGCHLD, record_signo);
  97
  98         /* TODO: SIGWINCH? pass window size changes down to slave? */
  99
 100         child_pid = xvfork();
 101
 102         if (child_pid) {
 103                 /* parent */
 104 #define buf bb_common_bufsiz1
 105                 struct pollfd pfd[2];
 106                 int outfd, count, loop;
 107                 double oldtime = ENABLE_SCRIPTREPLAY ? time(NULL) : 0;
 108                 smallint fd_count = 2;
 109
 110                 outfd = xopen(fname, mode);
 111                 pfd[0].fd = pty;
 112                 pfd[0].events = POLLIN;
 113                 pfd[1].fd = STDIN_FILENO;
 114                 pfd[1].events = POLLIN;
 115                 ndelay_on(pty); /* this descriptor is not shared, can do this */
 116                 /* ndelay_on(STDIN_FILENO); - NO, stdin can be shared! Pity :( */
 117
 118                 /* copy stdin to pty master input,
 119                  * copy pty master output to stdout and file */
 120                 /* TODO: don't use full_write's, use proper write buffering */
 121                 while (fd_count && !bb_got_signal) {
 122                         /* not safe_poll! we want SIGCHLD to EINTR poll */
 123                         if (poll(pfd, fd_count, -1) < 0 && errno != EINTR) {
 124                                 /* If child exits too quickly, we may get EIO:
 125                                  * for example, try "script -c true" */
 126                                 break;
 127                         }
 128                         if (pfd[0].revents) {
 129                                 errno = 0;
 130                                 count = safe_read(pty, buf, sizeof(buf));
 131                                 if (count <= 0 && errno != EAGAIN) {
 132                                         /* err/eof from pty: exit */
 133                                         goto restore;
 134                                 }
 135                                 if (count > 0) {
 136                                         if (ENABLE_SCRIPTREPLAY && (opt & OPT_t)) {
 137                                                 struct timeval tv;
 138                                                 double newtime;
 139
 140                                                 gettimeofday(&tv, NULL);
 141                                                 newtime = tv.tv_sec + (double) tv.tv_usec / 1000000;
 142                                                 fprintf(stderr, "%f %u\n", newtime - oldtime, count);
 143                                                 oldtime = newtime;
 144                                         }
 145                                         full_write(STDOUT_FILENO, buf, count);
 146                                         full_write(outfd, buf, count);
 147                                         if (opt & OPT_f) {
 148                                                 fsync(outfd);
 149                                         }
 150                                 }
 151                         }
 152                         if (pfd[1].revents) {
 153                                 count = safe_read(STDIN_FILENO, buf, sizeof(buf));
 154                                 if (count <= 0) {
 155                                         /* err/eof from stdin: don't read stdin anymore */
 156                                         pfd[1].revents = 0;
 157                                         fd_count--;
 158                                 } else {
 159                                         full_write(pty, buf, count);
 160                                 }
 161                         }
 162                 }
 163                 /* If loop was exited because SIGCHLD handler set bb_got_signal,
 164                  * there still can be some buffered output. But dont loop forever:
 165                  * we won't pump orphaned grandchildren's output indefinitely.
 166                  * Testcase: running this in script:
 167                  *      exec dd if=/dev/zero bs=1M count=1
 168                  * must have "1+0 records in, 1+0 records out" captured too.
 169                  * (util-linux's script doesn't do this. buggy :) */
 170                 loop = 999;
 171                 /* pty is in O_NONBLOCK mode, we exit as soon as buffer is empty */
 172                 while (--loop && (count = safe_read(pty, buf, sizeof(buf))) > 0) {
 173                         full_write(STDOUT_FILENO, buf, count);
 174                         full_write(outfd, buf, count);
 175                 }
 176  restore:
 177                 if (attr_ok == 0)
 178                         tcsetattr(0, TCSAFLUSH, &tt);
 179                 if (!(opt & OPT_q))
 180                         printf("Script done, file is %s\n", fname);
 181                 return EXIT_SUCCESS;
 182         }
 183
 184         /* child: make pty slave to be input, output, error; run shell */
 185         close(pty); /* close pty master */
 186         /* open pty slave to fd 0,1,2 */
 187         close(0);
 188         xopen(pty_line, O_RDWR); /* uses fd 0 */
 189         xdup2(0, 1);
 190         xdup2(0, 2);
 191         /* copy our original stdin tty's parameters to pty */
 192         if (attr_ok == 0)
 193                 tcsetattr(0, TCSAFLUSH, &tt);
 194         if (winsz_ok == 0)
 195                 ioctl(0, TIOCSWINSZ, (char *)&win);
 196         /* set pty as a controlling tty */
 197         setsid();
 198         ioctl(0, TIOCSCTTY, 0 /* 0: don't forcibly steal */);
 199
 200         /* Non-ignored signals revert to SIG_DFL on exec anyway */
 201         /*signal(SIGCHLD, SIG_DFL);*/
 202         execl(shell, shell, shell_opt, shell_arg, (char *) NULL);
 203         bb_simple_perror_msg_and_die(shell);
 204 }