LXR busybox/coreutils/tee.c

   1/* vi: set sw=4 ts=4: */
   2/*
   3 * tee implementation for busybox
   4 *
   5 * Copyright (C) 2003  Manuel Novoa III  <mjn3@codepoet.org>
   6 *
   7 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   8 */
   9//config:config TEE
  10//config:       bool "tee (4.2 kb)"
  11//config:       default y
  12//config:       help
  13//config:       tee is used to read from standard input and write
  14//config:       to standard output and files.
  15//config:
  16//config:config FEATURE_TEE_USE_BLOCK_IO
  17//config:       bool "Enable block I/O (larger/faster) instead of byte I/O"
  18//config:       default y
  19//config:       depends on TEE
  20//config:       help
  21//config:       Enable this option for a faster tee, at expense of size.
  22
  23//applet:IF_TEE(APPLET(tee, BB_DIR_USR_BIN, BB_SUID_DROP))
  24
  25//kbuild:lib-$(CONFIG_TEE) += tee.o
  26
  27/* BB_AUDIT SUSv3 compliant */
  28/* http://www.opengroup.org/onlinepubs/007904975/utilities/tee.html */
  29
  30//usage:#define tee_trivial_usage
  31//usage:       "[-ai] [FILE]..."
  32//usage:#define tee_full_usage "\n\n"
  33//usage:       "Copy stdin to each FILE, and also to stdout\n"
  34//usage:     "\n        -a      Append to the given FILEs, don't overwrite"
  35//usage:     "\n        -i      Ignore interrupt signals (SIGINT)"
  36//usage:
  37//usage:#define tee_example_usage
  38//usage:       "$ echo \"Hello\" | tee /tmp/foo\n"
  39//usage:       "$ cat /tmp/foo\n"
  40//usage:       "Hello\n"
  41
  42// Bare "tee" with no below options does not install SIGPIPE handler - just dies on it.
  43// TODO:
  44//      --output-error[=MODE]
  45//              'warn'          diagnose errors writing to any output
  46//              'warn-nopipe'   diagnose errors writing to any output not a pipe
  47//              'exit'          exit on error writing to any output
  48//              'exit-nopipe'   exit on error writing to any output not a pipe
  49// ^^^ all of these should set SIGPIPE to SIG_IGN.
  50// Because "exit" mode should print error message and exit1(1) - not die on SIGPIPE.
  51// "exit-nopipe" does not exit on EPIPE and does not set exitcode to 1 too.
  52//      -p      diagnose errors writing to non pipes
  53// ^^^^ this should set SIGPIPE to SIG_IGN. EPIPE is ignored (same as "warn-nopipe")
  54
  55#include "libbb.h"
  56#include "common_bufsiz.h"
  57
  58int tee_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  59int tee_main(int argc, char **argv)
  60{
  61        const char *mode = "w\0a";
  62        FILE **files;
  63        FILE **fp;
  64        char **names;
  65        char **np;
  66        char retval;
  67//TODO: make unconditional
  68#if ENABLE_FEATURE_TEE_USE_BLOCK_IO
  69        ssize_t c;
  70# define buf bb_common_bufsiz1
  71        setup_common_bufsiz();
  72#else
  73        int c;
  74#endif
  75        retval = getopt32(argv, "ia");  /* 'a' must be 2nd */
  76        argc -= optind;
  77        argv += optind;
  78
  79        mode += (retval & 2);   /* Since 'a' is the 2nd option... */
  80
  81        if (retval & 1) {
  82                signal(SIGINT, SIG_IGN);
  83        }
  84        retval = EXIT_SUCCESS;
  85        /* if (opt_p || opt_output_error)
  86                signal(SIGPIPE, SIG_IGN);
  87         */
  88
  89        /* Allocate an array of FILE *'s, with one extra for a sentinel. */
  90        fp = files = xzalloc(sizeof(FILE *) * (argc + 2));
  91        np = names = argv - 1;
  92
  93        files[0] = stdout;
  94        goto GOT_NEW_FILE;
  95
  96        do {
  97                *fp = stdout;
  98                if (NOT_LONE_DASH(*argv)) {
  99                        *fp = fopen_or_warn(*argv, mode);
 100                        if (*fp == NULL) {
 101                                retval = EXIT_FAILURE;
 102                                argv++;
 103                                continue;
 104                        }
 105                }
 106                *np = *argv++;
 107 GOT_NEW_FILE:
 108                setbuf(*fp, NULL);      /* tee must not buffer output. */
 109                fp++;
 110                np++;
 111        } while (*argv);
 112        /* names[0] will be filled later */
 113
 114#if ENABLE_FEATURE_TEE_USE_BLOCK_IO
 115        while ((c = safe_read(STDIN_FILENO, buf, COMMON_BUFSIZE)) > 0) {
 116                fp = files;
 117                do
 118                        fwrite(buf, 1, c, *fp);
 119                        /* if (opt_p && fwrite() != c && !EPIPE) bb_error_msg("..."); */
 120                while (*++fp);
 121        }
 122        if (c < 0) {            /* Make sure read errors are signaled. */
 123                retval = EXIT_FAILURE;
 124        }
 125#else
 126        setvbuf(stdout, NULL, _IONBF, 0);
 127        while ((c = getchar()) != EOF) {
 128                fp = files;
 129                do
 130                        putc(c, *fp);
 131                        /* if (opt_p && putc() == EOF && !EPIPE) bb_error_msg("..."); */
 132                while (*++fp);
 133        }
 134#endif
 135
 136        /* Now we need to check for i/o errors on stdin and the various
 137         * output files.  Since we know that the first entry in the output
 138         * file table is stdout, we can save one "if ferror" test by
 139         * setting the first entry to stdin and checking stdout error
 140         * status with fflush_stdout_and_exit()... although fflush()ing
 141         * is unnecessary here. */
 142        np = names;
 143        fp = files;
 144        names[0] = (char *) bb_msg_standard_input;
 145        files[0] = stdin;
 146        do {    /* Now check for input and output errors. */
 147                /* Checking ferror should be sufficient, but we may want to fclose.
 148                 * If we do, remember not to close stdin! */
 149                die_if_ferror(*fp++, *np++);
 150        } while (*fp);
 151
 152        fflush_stdout_and_exit(retval);
 153}
 154