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 = vfork();
  92         if (child_pid < 0) {
  93                 bb_perror_msg_and_die("vfork");
  94         }
  95
  96         if (child_pid) {
  97                 /* parent */
  98 #define buf bb_common_bufsiz1
  99                 struct pollfd pfd[2];
 100                 int outfd, count, loop;
 101                 double oldtime = ENABLE_SCRIPTREPLAY ? time(NULL) : 0;
 102                 smallint fd_count = 2;
 103
 104                 outfd = xopen(fname, mode);
 105                 pfd[0].fd = pty;
 106                 pfd[0].events = POLLIN;
 107                 pfd[1].fd = STDIN_FILENO;
 108                 pfd[1].events = POLLIN;
 109                 ndelay_on(pty); /* this descriptor is not shared, can do this */
 110                 /* ndelay_on(STDIN_FILENO); - NO, stdin can be shared! Pity :( */
 111
 112                 /* copy stdin to pty master input,
 113                  * copy pty master output to stdout and file */
 114                 /* TODO: don't use full_write's, use proper write buffering */
 115                 while (fd_count && !bb_got_signal) {
 116                         /* not safe_poll! we want SIGCHLD to EINTR poll */
 117                         if (poll(pfd, fd_count, -1) < 0 && errno != EINTR) {
 118                                 /* If child exits too quickly, we may get EIO:
 119                                  * for example, try "script -c true" */
 120                                 break;
 121                         }
 122                         if (pfd[0].revents) {
 123                                 errno = 0;
 124                                 count = safe_read(pty, buf, sizeof(buf));
 125                                 if (count <= 0 && errno != EAGAIN) {
 126                                         /* err/eof from pty: exit */
 127                                         goto restore;
 128                                 }
 129                                 if (count > 0) {
 130                                         if (ENABLE_SCRIPTREPLAY && (opt & OPT_t)) {
 131                                                 struct timeval tv;
 132                                                 double newtime;
 133
 134                                                 gettimeofday(&tv, NULL);
 135                                                 newtime = tv.tv_sec + (double) tv.tv_usec / 1000000;
 136                                                 fprintf(stderr, "%f %u\n", newtime - oldtime, count);
 137                                                 oldtime = newtime;
 138                                         }
 139                                         full_write(STDOUT_FILENO, buf, count);
 140                                         full_write(outfd, buf, count);
 141                                         if (opt & OPT_f) {
 142                                                 fsync(outfd);
 143                                         }
 144                                 }
 145                         }
 146                         if (pfd[1].revents) {
 147                                 count = safe_read(STDIN_FILENO, buf, sizeof(buf));
 148                                 if (count <= 0) {
 149                                         /* err/eof from stdin: don't read stdin anymore */
 150                                         pfd[1].revents = 0;
 151                                         fd_count--;
 152                                 } else {
 153                                         full_write(pty, buf, count);
 154                                 }
 155                         }
 156                 }
 157                 /* If loop was exited because SIGCHLD handler set bb_got_signal,
 158                  * there still can be some buffered output. But dont loop forever:
 159                  * we won't pump orphaned grandchildren's output indefinitely.
 160                  * Testcase: running this in script:
 161                  *      exec dd if=/dev/zero bs=1M count=1
 162                  * must have "1+0 records in, 1+0 records out" captured too.
 163                  * (util-linux's script doesn't do this. buggy :) */
 164                 loop = 999;
 165                 /* pty is in O_NONBLOCK mode, we exit as soon as buffer is empty */
 166                 while (--loop && (count = safe_read(pty, buf, sizeof(buf))) > 0) {
 167                         full_write(STDOUT_FILENO, buf, count);
 168                         full_write(outfd, buf, count);
 169                 }
 170  restore:
 171                 if (attr_ok == 0)
 172                         tcsetattr(0, TCSAFLUSH, &tt);
 173                 if (!(opt & OPT_q))
 174                         printf("Script done, file is %s\n", fname);
 175                 return EXIT_SUCCESS;
 176         }
 177
 178         /* child: make pty slave to be input, output, error; run shell */
 179         close(pty); /* close pty master */
 180         /* open pty slave to fd 0,1,2 */
 181         close(0);
 182         xopen(pty_line, O_RDWR); /* uses fd 0 */
 183         xdup2(0, 1);
 184         xdup2(0, 2);
 185         /* copy our original stdin tty's parameters to pty */
 186         if (attr_ok == 0)
 187                 tcsetattr(0, TCSAFLUSH, &tt);
 188         if (winsz_ok == 0)
 189                 ioctl(0, TIOCSWINSZ, (char *)&win);
 190         /* set pty as a controlling tty */
 191         setsid();
 192         ioctl(0, TIOCSCTTY, 0 /* 0: don't forcibly steal */);
 193
 194         /* Non-ignored signals revert to SIG_DFL on exec anyway */
 195         /*signal(SIGCHLD, SIG_DFL);*/
 196         execl(shell, shell, shell_opt, shell_arg, (char *) NULL);
 197         bb_simple_perror_msg_and_die(shell);
 198 }