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