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 //config:config SCRIPT
  14 //config:       bool "script (8 kb)"
  15 //config:       default y
  16 //config:       help
  17 //config:         The script makes typescript of terminal session.
  18
  19 //applet:IF_SCRIPT(APPLET(script, BB_DIR_USR_BIN, BB_SUID_DROP))
  20
  21 //kbuild:lib-$(CONFIG_SCRIPT) += script.o
  22
  23 //usage:#define script_trivial_usage
  24 //usage:       "[-afq" IF_SCRIPTREPLAY("t") "] [-c PROG] [OUTFILE]"
  25 //usage:#define script_full_usage "\n\n"
  26 //usage:       "        -a      Append output"
  27 //usage:     "\n        -c PROG Run PROG, not shell"
  28 //usage:     "\n        -f      Flush output after each write"
  29 //usage:     "\n        -q      Quiet"
  30 //usage:        IF_SCRIPTREPLAY(
  31 //usage:     "\n        -t      Send timing to stderr"
  32 //usage:        )
  33
  34 #include "libbb.h"
  35 #include "common_bufsiz.h"
  36
  37 int script_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  38 int script_main(int argc UNUSED_PARAM, char **argv)
  39 {
  40         int opt;
  41         int mode;
  42         int child_pid;
  43         int attr_ok; /* NB: 0: ok */
  44         int winsz_ok;
  45         int pty;
  46         char pty_line[GETPTY_BUFSIZE];
  47         struct termios tt, rtt;
  48         struct winsize win;
  49         const char *fname = "typescript";
  50         const char *shell;
  51         char shell_opt[] = "-i";
  52         char *shell_arg = NULL;
  53         enum {
  54                 OPT_a = (1 << 0),
  55                 OPT_c = (1 << 1),
  56                 OPT_f = (1 << 2),
  57                 OPT_q = (1 << 3),
  58                 OPT_t = (1 << 4),
  59         };
  60
  61 #if ENABLE_LONG_OPTS
  62         static const char getopt_longopts[] ALIGN1 =
  63                 "append\0"  No_argument       "a"
  64                 "command\0" Required_argument "c"
  65                 "flush\0"   No_argument       "f"
  66                 "quiet\0"   No_argument       "q"
  67                 IF_SCRIPTREPLAY("timing\0" No_argument "t")
  68                 ;
  69
  70         applet_long_options = getopt_longopts;
  71 #endif
  72
  73         opt_complementary = "?1"; /* max one arg */
  74         opt = getopt32(argv, "ac:fq" IF_SCRIPTREPLAY("t") , &shell_arg);
  75         //argc -= optind;
  76         argv += optind;
  77         if (argv[0]) {
  78                 fname = argv[0];
  79         }
  80         mode = O_CREAT|O_TRUNC|O_WRONLY;
  81         if (opt & OPT_a) {
  82                 mode = O_CREAT|O_APPEND|O_WRONLY;
  83         }
  84         if (opt & OPT_c) {
  85                 shell_opt[1] = 'c';
  86         }
  87         if (!(opt & OPT_q)) {
  88                 printf("Script started, file is %s\n", fname);
  89         }
  90
  91         shell = get_shell_name();
  92
  93         /* Some people run "script ... 0>&-".
  94          * Our code assumes that STDIN_FILENO != pty.
  95          * Ensure STDIN_FILENO is not closed:
  96          */
  97         bb_sanitize_stdio();
  98
  99         pty = xgetpty(pty_line);
 100
 101         /* get current stdin's tty params */
 102         attr_ok = tcgetattr(0, &tt);
 103         winsz_ok = ioctl(0, TIOCGWINSZ, (char *)&win);
 104
 105         rtt = tt;
 106         cfmakeraw(&rtt);
 107         rtt.c_lflag &= ~ECHO;
 108         tcsetattr(0, TCSAFLUSH, &rtt);
 109
 110         /* "script" from util-linux exits when child exits,
 111          * we wouldn't wait for EOF from slave pty
 112          * (output may be produced by grandchildren of child) */
 113         signal(SIGCHLD, record_signo);
 114
 115         /* TODO: SIGWINCH? pass window size changes down to slave? */
 116
 117         child_pid = xvfork();
 118
 119         if (child_pid) {
 120                 /* parent */
 121                 struct pollfd pfd[2];
 122                 int outfd, count, loop;
 123                 double oldtime = ENABLE_SCRIPTREPLAY ? time(NULL) : 0;
 124                 smallint fd_count = 2;
 125 #define buf bb_common_bufsiz1
 126                 setup_common_bufsiz();
 127
 128                 outfd = xopen(fname, mode);
 129                 pfd[0].fd = pty;
 130                 pfd[0].events = POLLIN;
 131                 pfd[1].fd = STDIN_FILENO;
 132                 pfd[1].events = POLLIN;
 133                 ndelay_on(pty); /* this descriptor is not shared, can do this */
 134                 /* ndelay_on(STDIN_FILENO); - NO, stdin can be shared! Pity :( */
 135
 136                 /* copy stdin to pty master input,
 137                  * copy pty master output to stdout and file */
 138                 /* TODO: don't use full_write's, use proper write buffering */
 139                 while (fd_count && !bb_got_signal) {
 140                         /* not safe_poll! we want SIGCHLD to EINTR poll */
 141                         if (poll(pfd, fd_count, -1) < 0 && errno != EINTR) {
 142                                 /* If child exits too quickly, we may get EIO:
 143                                  * for example, try "script -c true" */
 144                                 break;
 145                         }
 146                         if (pfd[0].revents) {
 147                                 errno = 0;
 148                                 count = safe_read(pty, buf, COMMON_BUFSIZE);
 149                                 if (count <= 0 && errno != EAGAIN) {
 150                                         /* err/eof from pty: exit */
 151                                         goto restore;
 152                                 }
 153                                 if (count > 0) {
 154                                         if (ENABLE_SCRIPTREPLAY && (opt & OPT_t)) {
 155                                                 struct timeval tv;
 156                                                 double newtime;
 157
 158                                                 gettimeofday(&tv, NULL);
 159                                                 newtime = tv.tv_sec + (double) tv.tv_usec / 1000000;
 160                                                 fprintf(stderr, "%f %u\n", newtime - oldtime, count);
 161                                                 oldtime = newtime;
 162                                         }
 163                                         full_write(STDOUT_FILENO, buf, count);
 164                                         full_write(outfd, buf, count);
 165                                         if (opt & OPT_f) {
 166                                                 fsync(outfd);
 167                                         }
 168                                 }
 169                         }
 170                         if (pfd[1].revents) {
 171                                 count = safe_read(STDIN_FILENO, buf, COMMON_BUFSIZE);
 172                                 if (count <= 0) {
 173                                         /* err/eof from stdin: don't read stdin anymore */
 174                                         pfd[1].revents = 0;
 175                                         fd_count--;
 176                                 } else {
 177                                         full_write(pty, buf, count);
 178                                 }
 179                         }
 180                 }
 181                 /* If loop was exited because SIGCHLD handler set bb_got_signal,
 182                  * there still can be some buffered output. But dont loop forever:
 183                  * we won't pump orphaned grandchildren's output indefinitely.
 184                  * Testcase: running this in script:
 185                  *      exec dd if=/dev/zero bs=1M count=1
 186                  * must have "1+0 records in, 1+0 records out" captured too.
 187                  * (util-linux's script doesn't do this. buggy :) */
 188                 loop = 999;
 189                 /* pty is in O_NONBLOCK mode, we exit as soon as buffer is empty */
 190                 while (--loop && (count = safe_read(pty, buf, COMMON_BUFSIZE)) > 0) {
 191                         full_write(STDOUT_FILENO, buf, count);
 192                         full_write(outfd, buf, count);
 193                 }
 194  restore:
 195                 if (attr_ok == 0)
 196                         tcsetattr(0, TCSAFLUSH, &tt);
 197                 if (!(opt & OPT_q))
 198                         printf("Script done, file is %s\n", fname);
 199                 return EXIT_SUCCESS;
 200         }
 201
 202         /* child: make pty slave to be input, output, error; run shell */
 203         close(pty); /* close pty master */
 204         /* open pty slave to fd 0,1,2 */
 205         close(0);
 206         xopen(pty_line, O_RDWR); /* uses fd 0 */
 207         xdup2(0, 1);
 208         xdup2(0, 2);
 209         /* copy our original stdin tty's parameters to pty */
 210         if (attr_ok == 0)
 211                 tcsetattr(0, TCSAFLUSH, &tt);
 212         if (winsz_ok == 0)
 213                 ioctl(0, TIOCSWINSZ, (char *)&win);
 214         /* set pty as a controlling tty */
 215         setsid();
 216         ioctl(0, TIOCSCTTY, 0 /* 0: don't forcibly steal */);
 217
 218         /* Non-ignored signals revert to SIG_DFL on exec anyway */
 219         /*signal(SIGCHLD, SIG_DFL);*/
 220         execl(shell, shell, shell_opt, shell_arg, (char *) NULL);
 221         bb_simple_perror_msg_and_die(shell);
 222 }