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] [-t[FILE]] [-c PROG] [OUTFILE]"
  25 //usage:#define script_full_usage "\n\n"
  26 //usage:       "Default OUTFILE is 'typescript'"
  27 //usage:     "\n"
  28 //usage:     "\n        -a      Append output"
  29 //usage:     "\n        -c PROG Run PROG, not shell"
  30 /* Accepted but has no effect (we never buffer output) */
  31 /*//usage:     "\n      -f      Flush output after each write"*/
  32 //usage:     "\n        -q      Quiet"
  33 //usage:     "\n        -t[FILE] Send timing to stderr or FILE"
  34
  35 //util-linux-2.28:
  36 //-e: return exit code of the child
  37
  38 //FYI (reported as bbox bug #2749):
  39 // > script -q -c 'echo -e -n "1\n2\n3\n"' /dev/null </dev/null >123.txt
  40 // > The output file on full-blown ubuntu system contains 6 bytes.
  41 // > Output on Busybox system (arm-linux) contains extra '\r' byte in each line.
  42 //however, in my test, "script" from util-linux-2.28 seems to also add '\r' bytes.
  43
  44 #include "libbb.h"
  45 #include "common_bufsiz.h"
  46
  47 int script_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  48 int script_main(int argc UNUSED_PARAM, char **argv)
  49 {
  50         int opt;
  51         int mode;
  52         int child_pid;
  53         int attr_ok; /* NB: 0: ok */
  54         int winsz_ok;
  55         int pty;
  56         char pty_line[GETPTY_BUFSIZE];
  57         struct termios tt, rtt;
  58         struct winsize win;
  59         FILE *timing_fp;
  60         const char *str_t = NULL;
  61         const char *fname = "typescript";
  62         const char *shell;
  63         char shell_opt[] = "-i";
  64         char *shell_arg = NULL;
  65         enum {
  66                 OPT_a = (1 << 0),
  67                 OPT_c = (1 << 1),
  68                 OPT_f = (1 << 2),
  69                 OPT_q = (1 << 3),
  70                 OPT_t = (1 << 4),
  71         };
  72
  73 #if ENABLE_LONG_OPTS
  74         static const char script_longopts[] ALIGN1 =
  75                 "append\0"  No_argument       "a"
  76                 "command\0" Required_argument "c"
  77                 "flush\0"   No_argument       "f"
  78                 "quiet\0"   No_argument       "q"
  79                 "timing\0"  Optional_argument "t"
  80                 ;
  81 #endif
  82
  83         opt = getopt32long(argv, "^" "ac:fqt::" "\0" "?1"/* max one arg */,
  84                                 script_longopts,
  85                                 &shell_arg, &str_t
  86         );
  87         //argc -= optind;
  88         argv += optind;
  89         if (argv[0]) {
  90                 fname = argv[0];
  91         }
  92         mode = O_CREAT|O_TRUNC|O_WRONLY;
  93         if (opt & OPT_a) {
  94                 mode = O_CREAT|O_APPEND|O_WRONLY;
  95         }
  96         if (opt & OPT_c) {
  97                 shell_opt[1] = 'c';
  98         }
  99         if (!(opt & OPT_q)) {
 100                 printf("Script started, file is %s\n", fname);
 101         }
 102         timing_fp = stderr;
 103         if (str_t) {
 104                 timing_fp = xfopen_for_write(str_t);
 105         }
 106
 107         shell = get_shell_name();
 108
 109         /* Some people run "script ... 0>&-".
 110          * Our code assumes that STDIN_FILENO != pty.
 111          * Ensure STDIN_FILENO is not closed:
 112          */
 113         bb_sanitize_stdio();
 114
 115         pty = xgetpty(pty_line);
 116
 117         /* get current stdin's tty params */
 118         attr_ok = tcgetattr(0, &tt);
 119         winsz_ok = ioctl(0, TIOCGWINSZ, (char *)&win);
 120
 121         rtt = tt;
 122         cfmakeraw(&rtt);
 123         rtt.c_lflag &= ~ECHO;
 124         tcsetattr(0, TCSAFLUSH, &rtt);
 125
 126         /* "script" from util-linux exits when child exits,
 127          * we wouldn't wait for EOF from slave pty
 128          * (output may be produced by grandchildren of child) */
 129         signal(SIGCHLD, record_signo);
 130
 131         /* TODO: SIGWINCH? pass window size changes down to slave? */
 132
 133         child_pid = xvfork();
 134
 135         if (child_pid) {
 136                 /* parent */
 137                 struct pollfd pfd[2];
 138                 int outfd, count, loop;
 139                 double oldtime = time(NULL);
 140                 smallint fd_count = 2;
 141
 142 #define buf bb_common_bufsiz1
 143                 setup_common_bufsiz();
 144
 145                 outfd = xopen(fname, mode);
 146                 pfd[0].fd = pty;
 147                 pfd[0].events = POLLIN;
 148                 pfd[1].fd = STDIN_FILENO;
 149                 pfd[1].events = POLLIN;
 150                 ndelay_on(pty); /* this descriptor is not shared, can do this */
 151                 /* ndelay_on(STDIN_FILENO); - NO, stdin can be shared! Pity :( */
 152
 153                 /* copy stdin to pty master input,
 154                  * copy pty master output to stdout and file */
 155                 /* TODO: don't use full_write's, use proper write buffering */
 156                 while (fd_count && !bb_got_signal) {
 157                         /* not safe_poll! we want SIGCHLD to EINTR poll */
 158                         if (poll(pfd, fd_count, -1) < 0 && errno != EINTR) {
 159                                 /* If child exits too quickly, we may get EIO:
 160                                  * for example, try "script -c true" */
 161                                 break;
 162                         }
 163                         if (pfd[0].revents) {
 164                                 errno = 0;
 165                                 count = safe_read(pty, buf, COMMON_BUFSIZE);
 166                                 if (count <= 0 && errno != EAGAIN) {
 167                                         /* err/eof from pty: exit */
 168                                         goto restore;
 169                                 }
 170                                 if (count > 0) {
 171                                         if (opt & OPT_t) {
 172                                                 struct timeval tv;
 173                                                 double newtime;
 174
 175                                                 gettimeofday(&tv, NULL);
 176                                                 newtime = tv.tv_sec + (double) tv.tv_usec / 1000000;
 177                                                 fprintf(timing_fp, "%f %u\n", newtime - oldtime, count);
 178                                                 oldtime = newtime;
 179                                         }
 180                                         full_write(STDOUT_FILENO, buf, count);
 181                                         full_write(outfd, buf, count);
 182                                         // If we'd be using (buffered) FILE i/o, we'd need this:
 183                                         //if (opt & OPT_f) {
 184                                         //      fflush(outfd);
 185                                         //}
 186                                 }
 187                         }
 188                         if (pfd[1].revents) {
 189                                 count = safe_read(STDIN_FILENO, buf, COMMON_BUFSIZE);
 190                                 if (count <= 0) {
 191                                         /* err/eof from stdin: don't read stdin anymore */
 192                                         pfd[1].revents = 0;
 193                                         fd_count--;
 194                                 } else {
 195                                         full_write(pty, buf, count);
 196                                 }
 197                         }
 198                 }
 199                 /* If loop was exited because SIGCHLD handler set bb_got_signal,
 200                  * there still can be some buffered output. But dont loop forever:
 201                  * we won't pump orphaned grandchildren's output indefinitely.
 202                  * Testcase: running this in script:
 203                  *      exec dd if=/dev/zero bs=1M count=1
 204                  * must have "1+0 records in, 1+0 records out" captured too.
 205                  * (util-linux's script doesn't do this. buggy :) */
 206                 loop = 999;
 207                 /* pty is in O_NONBLOCK mode, we exit as soon as buffer is empty */
 208                 while (--loop && (count = safe_read(pty, buf, COMMON_BUFSIZE)) > 0) {
 209                         full_write(STDOUT_FILENO, buf, count);
 210                         full_write(outfd, buf, count);
 211                 }
 212  restore:
 213                 if (attr_ok == 0)
 214                         tcsetattr(0, TCSAFLUSH, &tt);
 215                 if (!(opt & OPT_q))
 216                         printf("Script done, file is %s\n", fname);
 217                 return EXIT_SUCCESS;
 218         }
 219
 220         /* child: make pty slave to be input, output, error; run shell */
 221         close(pty); /* close pty master */
 222         /* open pty slave to fd 0,1,2 */
 223         close(0);
 224         xopen(pty_line, O_RDWR); /* uses fd 0 */
 225         xdup2(0, 1);
 226         xdup2(0, 2);
 227         /* copy our original stdin tty's parameters to pty */
 228         if (attr_ok == 0)
 229                 tcsetattr(0, TCSAFLUSH, &tt);
 230         if (winsz_ok == 0)
 231                 ioctl(0, TIOCSWINSZ, (char *)&win);
 232         /* set pty as a controlling tty */
 233         setsid();
 234         ioctl(0, TIOCSCTTY, 0 /* 0: don't forcibly steal */);
 235
 236         /* Non-ignored signals revert to SIG_DFL on exec anyway */
 237         /*signal(SIGCHLD, SIG_DFL);*/
 238         execl(shell, shell, shell_opt, shell_arg, (char *) NULL);
 239         bb_simple_perror_msg_and_die(shell);
 240 }