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:       "[-afqt] [-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:     "\n        -t      Send timing to stderr"
  31
  32 //util-linux-2.28:
  33 //-t[FILE]
  34 //-e: return exit code of the child
  35
  36 //FYI (reported as bbox bug #2749):
  37 // > script -q -c 'echo -e -n "1\n2\n3\n"' /dev/null </dev/null >123.txt
  38 // > The output file on full-blown ubuntu system contains 6 bytes.
  39 // > Output on Busybox system (arm-linux) contains extra '\r' byte in each line.
  40 //however, in my test, "script" from util-linux-2.28 seems to also add '\r' bytes.
  41
  42 #include "libbb.h"
  43 #include "common_bufsiz.h"
  44
  45 int script_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  46 int script_main(int argc UNUSED_PARAM, char **argv)
  47 {
  48         int opt;
  49         int mode;
  50         int child_pid;
  51         int attr_ok; /* NB: 0: ok */
  52         int winsz_ok;
  53         int pty;
  54         char pty_line[GETPTY_BUFSIZE];
  55         struct termios tt, rtt;
  56         struct winsize win;
  57         const char *fname = "typescript";
  58         const char *shell;
  59         char shell_opt[] = "-i";
  60         char *shell_arg = NULL;
  61         enum {
  62                 OPT_a = (1 << 0),
  63                 OPT_c = (1 << 1),
  64                 OPT_f = (1 << 2),
  65                 OPT_q = (1 << 3),
  66                 OPT_t = (1 << 4),
  67         };
  68
  69 #if ENABLE_LONG_OPTS
  70         static const char getopt_longopts[] ALIGN1 =
  71                 "append\0"  No_argument       "a"
  72                 "command\0" Required_argument "c"
  73                 "flush\0"   No_argument       "f"
  74                 "quiet\0"   No_argument       "q"
  75                 "timing\0"  No_argument       "t"
  76                 ;
  77
  78         applet_long_options = getopt_longopts;
  79 #endif
  80
  81         opt_complementary = "?1"; /* max one arg */
  82         opt = getopt32(argv, "ac:fqt", &shell_arg);
  83         //argc -= optind;
  84         argv += optind;
  85         if (argv[0]) {
  86                 fname = argv[0];
  87         }
  88         mode = O_CREAT|O_TRUNC|O_WRONLY;
  89         if (opt & OPT_a) {
  90                 mode = O_CREAT|O_APPEND|O_WRONLY;
  91         }
  92         if (opt & OPT_c) {
  93                 shell_opt[1] = 'c';
  94         }
  95         if (!(opt & OPT_q)) {
  96                 printf("Script started, file is %s\n", fname);
  97         }
  98
  99         shell = get_shell_name();
 100
 101         /* Some people run "script ... 0>&-".
 102          * Our code assumes that STDIN_FILENO != pty.
 103          * Ensure STDIN_FILENO is not closed:
 104          */
 105         bb_sanitize_stdio();
 106
 107         pty = xgetpty(pty_line);
 108
 109         /* get current stdin's tty params */
 110         attr_ok = tcgetattr(0, &tt);
 111         winsz_ok = ioctl(0, TIOCGWINSZ, (char *)&win);
 112
 113         rtt = tt;
 114         cfmakeraw(&rtt);
 115         rtt.c_lflag &= ~ECHO;
 116         tcsetattr(0, TCSAFLUSH, &rtt);
 117
 118         /* "script" from util-linux exits when child exits,
 119          * we wouldn't wait for EOF from slave pty
 120          * (output may be produced by grandchildren of child) */
 121         signal(SIGCHLD, record_signo);
 122
 123         /* TODO: SIGWINCH? pass window size changes down to slave? */
 124
 125         child_pid = xvfork();
 126
 127         if (child_pid) {
 128                 /* parent */
 129                 struct pollfd pfd[2];
 130                 int outfd, count, loop;
 131                 double oldtime = time(NULL);
 132                 smallint fd_count = 2;
 133 #define buf bb_common_bufsiz1
 134                 setup_common_bufsiz();
 135
 136                 outfd = xopen(fname, mode);
 137                 pfd[0].fd = pty;
 138                 pfd[0].events = POLLIN;
 139                 pfd[1].fd = STDIN_FILENO;
 140                 pfd[1].events = POLLIN;
 141                 ndelay_on(pty); /* this descriptor is not shared, can do this */
 142                 /* ndelay_on(STDIN_FILENO); - NO, stdin can be shared! Pity :( */
 143
 144                 /* copy stdin to pty master input,
 145                  * copy pty master output to stdout and file */
 146                 /* TODO: don't use full_write's, use proper write buffering */
 147                 while (fd_count && !bb_got_signal) {
 148                         /* not safe_poll! we want SIGCHLD to EINTR poll */
 149                         if (poll(pfd, fd_count, -1) < 0 && errno != EINTR) {
 150                                 /* If child exits too quickly, we may get EIO:
 151                                  * for example, try "script -c true" */
 152                                 break;
 153                         }
 154                         if (pfd[0].revents) {
 155                                 errno = 0;
 156                                 count = safe_read(pty, buf, COMMON_BUFSIZE);
 157                                 if (count <= 0 && errno != EAGAIN) {
 158                                         /* err/eof from pty: exit */
 159                                         goto restore;
 160                                 }
 161                                 if (count > 0) {
 162                                         if (opt & OPT_t) {
 163                                                 struct timeval tv;
 164                                                 double newtime;
 165
 166                                                 gettimeofday(&tv, NULL);
 167                                                 newtime = tv.tv_sec + (double) tv.tv_usec / 1000000;
 168                                                 fprintf(stderr, "%f %u\n", newtime - oldtime, count);
 169                                                 oldtime = newtime;
 170                                         }
 171                                         full_write(STDOUT_FILENO, buf, count);
 172                                         full_write(outfd, buf, count);
 173                                         if (opt & OPT_f) {
 174                                                 fsync(outfd);
 175                                         }
 176                                 }
 177                         }
 178                         if (pfd[1].revents) {
 179                                 count = safe_read(STDIN_FILENO, buf, COMMON_BUFSIZE);
 180                                 if (count <= 0) {
 181                                         /* err/eof from stdin: don't read stdin anymore */
 182                                         pfd[1].revents = 0;
 183                                         fd_count--;
 184                                 } else {
 185                                         full_write(pty, buf, count);
 186                                 }
 187                         }
 188                 }
 189                 /* If loop was exited because SIGCHLD handler set bb_got_signal,
 190                  * there still can be some buffered output. But dont loop forever:
 191                  * we won't pump orphaned grandchildren's output indefinitely.
 192                  * Testcase: running this in script:
 193                  *      exec dd if=/dev/zero bs=1M count=1
 194                  * must have "1+0 records in, 1+0 records out" captured too.
 195                  * (util-linux's script doesn't do this. buggy :) */
 196                 loop = 999;
 197                 /* pty is in O_NONBLOCK mode, we exit as soon as buffer is empty */
 198                 while (--loop && (count = safe_read(pty, buf, COMMON_BUFSIZE)) > 0) {
 199                         full_write(STDOUT_FILENO, buf, count);
 200                         full_write(outfd, buf, count);
 201                 }
 202  restore:
 203                 if (attr_ok == 0)
 204                         tcsetattr(0, TCSAFLUSH, &tt);
 205                 if (!(opt & OPT_q))
 206                         printf("Script done, file is %s\n", fname);
 207                 return EXIT_SUCCESS;
 208         }
 209
 210         /* child: make pty slave to be input, output, error; run shell */
 211         close(pty); /* close pty master */
 212         /* open pty slave to fd 0,1,2 */
 213         close(0);
 214         xopen(pty_line, O_RDWR); /* uses fd 0 */
 215         xdup2(0, 1);
 216         xdup2(0, 2);
 217         /* copy our original stdin tty's parameters to pty */
 218         if (attr_ok == 0)
 219                 tcsetattr(0, TCSAFLUSH, &tt);
 220         if (winsz_ok == 0)
 221                 ioctl(0, TIOCSWINSZ, (char *)&win);
 222         /* set pty as a controlling tty */
 223         setsid();
 224         ioctl(0, TIOCSCTTY, 0 /* 0: don't forcibly steal */);
 225
 226         /* Non-ignored signals revert to SIG_DFL on exec anyway */
 227         /*signal(SIGCHLD, SIG_DFL);*/
 228         execl(shell, shell, shell_opt, shell_arg, (char *) NULL);
 229         bb_simple_perror_msg_and_die(shell);
 230 }