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 (4.3 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#include "libbb.h"
  43#include "common_bufsiz.h"
  44
  45int tee_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  46int tee_main(int argc, char **argv)
  47{
  48        const char *mode = "w\0a";
  49        FILE **files;
  50        FILE **fp;
  51        char **names;
  52        char **np;
  53        char retval;
  54//TODO: make unconditional
  55#if ENABLE_FEATURE_TEE_USE_BLOCK_IO
  56        ssize_t c;
  57# define buf bb_common_bufsiz1
  58        setup_common_bufsiz();
  59#else
  60        int c;
  61#endif
  62        retval = getopt32(argv, "ia");  /* 'a' must be 2nd */
  63        argc -= optind;
  64        argv += optind;
  65
  66        mode += (retval & 2);   /* Since 'a' is the 2nd option... */
  67
  68        if (retval & 1) {
  69                signal(SIGINT, SIG_IGN); /* TODO - switch to sigaction. (why?) */
  70        }
  71        retval = EXIT_SUCCESS;
  72        /* gnu tee ignores SIGPIPE in case one of the output files is a pipe
  73         * that doesn't consume all its input.  Good idea... */
  74        signal(SIGPIPE, SIG_IGN);
  75
  76        /* Allocate an array of FILE *'s, with one extra for a sentinel. */
  77        fp = files = xzalloc(sizeof(FILE *) * (argc + 2));
  78        np = names = argv - 1;
  79
  80        files[0] = stdout;
  81        goto GOT_NEW_FILE;
  82        do {
  83                *fp = stdout;
  84                if (NOT_LONE_DASH(*argv)) {
  85                        *fp = fopen_or_warn(*argv, mode);
  86                        if (*fp == NULL) {
  87                                retval = EXIT_FAILURE;
  88                                argv++;
  89                                continue;
  90                        }
  91                }
  92                *np = *argv++;
  93 GOT_NEW_FILE:
  94                setbuf(*fp, NULL);      /* tee must not buffer output. */
  95                fp++;
  96                np++;
  97        } while (*argv);
  98        /* names[0] will be filled later */
  99
 100#if ENABLE_FEATURE_TEE_USE_BLOCK_IO
 101        while ((c = safe_read(STDIN_FILENO, buf, COMMON_BUFSIZE)) > 0) {
 102                fp = files;
 103                do
 104                        fwrite(buf, 1, c, *fp);
 105                while (*++fp);
 106        }
 107        if (c < 0) {            /* Make sure read errors are signaled. */
 108                retval = EXIT_FAILURE;
 109        }
 110#else
 111        setvbuf(stdout, NULL, _IONBF, 0);
 112        while ((c = getchar()) != EOF) {
 113                fp = files;
 114                do
 115                        putc(c, *fp);
 116                while (*++fp);
 117        }
 118#endif
 119
 120        /* Now we need to check for i/o errors on stdin and the various
 121         * output files.  Since we know that the first entry in the output
 122         * file table is stdout, we can save one "if ferror" test by
 123         * setting the first entry to stdin and checking stdout error
 124         * status with fflush_stdout_and_exit()... although fflush()ing
 125         * is unnecessary here. */
 126        np = names;
 127        fp = files;
 128        names[0] = (char *) bb_msg_standard_input;
 129        files[0] = stdin;
 130        do {    /* Now check for input and output errors. */
 131                /* Checking ferror should be sufficient, but we may want to fclose.
 132                 * If we do, remember not to close stdin! */
 133                die_if_ferror(*fp++, *np++);
 134        } while (*fp);
 135
 136        fflush_stdout_and_exit(retval);
 137}
 138