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 //usage:     "\n        -f      Flush output after each write"
  31 //usage:     "\n        -q      Quiet"
  32 //usage:     "\n        -t[FILE] Send timing to stderr or FILE"
  33
  34 //util-linux-2.28:
  35 //-e: return exit code of the child
  36
  37 //FYI (reported as bbox bug #2749):
  38 // > script -q -c 'echo -e -n "1\n2\n3\n"' /dev/null </dev/null >123.txt
  39 // > The output file on full-blown ubuntu system contains 6 bytes.
  40 // > Output on Busybox system (arm-linux) contains extra '\r' byte in each line.
  41 //however, in my test, "script" from util-linux-2.28 seems to also add '\r' bytes.
  42
  43 #include "libbb.h"
  44 #include "common_bufsiz.h"
  45
  46 int script_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  47 int script_main(int argc UNUSED_PARAM, char **argv)
  48 {
  49         int opt;
  50         int mode;
  51         int child_pid;
  52         int attr_ok; /* NB: 0: ok */
  53         int winsz_ok;
  54         int pty;
  55         char pty_line[GETPTY_BUFSIZE];
  56         struct termios tt, rtt;
  57         struct winsize win;
  58         FILE *timing_fp;
  59         const char *str_t = NULL;
  60         const char *fname = "typescript";
  61         const char *shell;
  62         char shell_opt[] = "-i";
  63         char *shell_arg = NULL;
  64         enum {
  65                 OPT_a = (1 << 0),
  66                 OPT_c = (1 << 1),
  67                 OPT_f = (1 << 2),
  68                 OPT_q = (1 << 3),
  69                 OPT_t = (1 << 4),
  70         };
  71
  72 #if ENABLE_LONG_OPTS
  73         static const char getopt_longopts[] ALIGN1 =
  74                 "append\0"  No_argument       "a"
  75                 "command\0" Required_argument "c"
  76                 "flush\0"   No_argument       "f"
  77                 "quiet\0"   No_argument       "q"
  78                 "timing\0"  Optional_argument "t"
  79                 ;
  80
  81         applet_long_options = getopt_longopts;
  82 #endif
  83
  84         opt_complementary = "?1"; /* max one arg */
  85         opt = getopt32(argv, "ac:fqt::", &shell_arg, &str_t);
  86         //argc -= optind;
  87         argv += optind;
  88         if (argv[0]) {
  89                 fname = argv[0];
  90         }
  91         mode = O_CREAT|O_TRUNC|O_WRONLY;
  92         if (opt & OPT_a) {
  93                 mode = O_CREAT|O_APPEND|O_WRONLY;
  94         }
  95         if (opt & OPT_c) {
  96                 shell_opt[1] = 'c';
  97         }
  98         if (!(opt & OPT_q)) {
  99                 printf("Script started, file is %s\n", fname);
 100         }
 101         timing_fp = stderr;
 102         if (str_t) {
 103                 timing_fp = xfopen_for_write(str_t);
 104         }
 105
 106         shell = get_shell_name();
 107
 108         /* Some people run "script ... 0>&-".
 109          * Our code assumes that STDIN_FILENO != pty.
 110          * Ensure STDIN_FILENO is not closed:
 111          */
 112         bb_sanitize_stdio();
 113
 114         pty = xgetpty(pty_line);
 115
 116         /* get current stdin's tty params */
 117         attr_ok = tcgetattr(0, &tt);
 118         winsz_ok = ioctl(0, TIOCGWINSZ, (char *)&win);
 119
 120         rtt = tt;
 121         cfmakeraw(&rtt);
 122         rtt.c_lflag &= ~ECHO;
 123         tcsetattr(0, TCSAFLUSH, &rtt);
 124
 125         /* "script" from util-linux exits when child exits,
 126          * we wouldn't wait for EOF from slave pty
 127          * (output may be produced by grandchildren of child) */
 128         signal(SIGCHLD, record_signo);
 129
 130         /* TODO: SIGWINCH? pass window size changes down to slave? */
 131
 132         child_pid = xvfork();
 133
 134         if (child_pid) {
 135                 /* parent */
 136                 struct pollfd pfd[2];
 137                 int outfd, count, loop;
 138                 double oldtime = time(NULL);
 139                 smallint fd_count = 2;
 140
 141 #define buf bb_common_bufsiz1
 142                 setup_common_bufsiz();
 143
 144                 outfd = xopen(fname, mode);
 145                 pfd[0].fd = pty;
 146                 pfd[0].events = POLLIN;
 147                 pfd[1].fd = STDIN_FILENO;
 148                 pfd[1].events = POLLIN;
 149                 ndelay_on(pty); /* this descriptor is not shared, can do this */
 150                 /* ndelay_on(STDIN_FILENO); - NO, stdin can be shared! Pity :( */
 151
 152                 /* copy stdin to pty master input,
 153                  * copy pty master output to stdout and file */
 154                 /* TODO: don't use full_write's, use proper write buffering */
 155                 while (fd_count && !bb_got_signal) {
 156                         /* not safe_poll! we want SIGCHLD to EINTR poll */
 157                         if (poll(pfd, fd_count, -1) < 0 && errno != EINTR) {
 158                                 /* If child exits too quickly, we may get EIO:
 159                                  * for example, try "script -c true" */
 160                                 break;
 161                         }
 162                         if (pfd[0].revents) {
 163                                 errno = 0;
 164                                 count = safe_read(pty, buf, COMMON_BUFSIZE);
 165                                 if (count <= 0 && errno != EAGAIN) {
 166                                         /* err/eof from pty: exit */
 167                                         goto restore;
 168                                 }
 169                                 if (count > 0) {
 170                                         if (opt & OPT_t) {
 171                                                 struct timeval tv;
 172                                                 double newtime;
 173
 174                                                 gettimeofday(&tv, NULL);
 175                                                 newtime = tv.tv_sec + (double) tv.tv_usec / 1000000;
 176                                                 fprintf(timing_fp, "%f %u\n", newtime - oldtime, count);
 177                                                 oldtime = newtime;
 178                                         }
 179                                         full_write(STDOUT_FILENO, buf, count);
 180                                         full_write(outfd, buf, count);
 181                                         if (opt & OPT_f) {
 182                                                 fsync(outfd);
 183                                         }
 184                                 }
 185                         }
 186                         if (pfd[1].revents) {
 187                                 count = safe_read(STDIN_FILENO, buf, COMMON_BUFSIZE);
 188                                 if (count <= 0) {
 189                                         /* err/eof from stdin: don't read stdin anymore */
 190                                         pfd[1].revents = 0;
 191                                         fd_count--;
 192                                 } else {
 193                                         full_write(pty, buf, count);
 194                                 }
 195                         }
 196                 }
 197                 /* If loop was exited because SIGCHLD handler set bb_got_signal,
 198                  * there still can be some buffered output. But dont loop forever:
 199                  * we won't pump orphaned grandchildren's output indefinitely.
 200                  * Testcase: running this in script:
 201                  *      exec dd if=/dev/zero bs=1M count=1
 202                  * must have "1+0 records in, 1+0 records out" captured too.
 203                  * (util-linux's script doesn't do this. buggy :) */
 204                 loop = 999;
 205                 /* pty is in O_NONBLOCK mode, we exit as soon as buffer is empty */
 206                 while (--loop && (count = safe_read(pty, buf, COMMON_BUFSIZE)) > 0) {
 207                         full_write(STDOUT_FILENO, buf, count);
 208                         full_write(outfd, buf, count);
 209                 }
 210  restore:
 211                 if (attr_ok == 0)
 212                         tcsetattr(0, TCSAFLUSH, &tt);
 213                 if (!(opt & OPT_q))
 214                         printf("Script done, file is %s\n", fname);
 215                 return EXIT_SUCCESS;
 216         }
 217
 218         /* child: make pty slave to be input, output, error; run shell */
 219         close(pty); /* close pty master */
 220         /* open pty slave to fd 0,1,2 */
 221         close(0);
 222         xopen(pty_line, O_RDWR); /* uses fd 0 */
 223         xdup2(0, 1);
 224         xdup2(0, 2);
 225         /* copy our original stdin tty's parameters to pty */
 226         if (attr_ok == 0)
 227                 tcsetattr(0, TCSAFLUSH, &tt);
 228         if (winsz_ok == 0)
 229                 ioctl(0, TIOCSWINSZ, (char *)&win);
 230         /* set pty as a controlling tty */
 231         setsid();
 232         ioctl(0, TIOCSCTTY, 0 /* 0: don't forcibly steal */);
 233
 234         /* Non-ignored signals revert to SIG_DFL on exec anyway */
 235         /*signal(SIGCHLD, SIG_DFL);*/
 236         execl(shell, shell, shell_opt, shell_arg, (char *) NULL);
 237         bb_simple_perror_msg_and_die(shell);
 238 }