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 tarball for details.
   8 */
   9
  10/* BB_AUDIT SUSv3 compliant */
  11/* http://www.opengroup.org/onlinepubs/007904975/utilities/tee.html */
  12
  13#include "libbb.h"
  14
  15int tee_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  16int tee_main(int argc, char **argv)
  17{
  18        const char *mode = "w\0a";
  19        FILE **files;
  20        FILE **fp;
  21        char **names;
  22        char **np;
  23        char retval;
  24//TODO: make unconditional
  25#if ENABLE_FEATURE_TEE_USE_BLOCK_IO
  26        ssize_t c;
  27# define buf bb_common_bufsiz1
  28#else
  29        int c;
  30#endif
  31        retval = getopt32(argv, "ia");  /* 'a' must be 2nd */
  32        argc -= optind;
  33        argv += optind;
  34
  35        mode += (retval & 2);   /* Since 'a' is the 2nd option... */
  36
  37        if (retval & 1) {
  38                signal(SIGINT, SIG_IGN); /* TODO - switch to sigaction. (why?) */
  39        }
  40        retval = EXIT_SUCCESS;
  41        /* gnu tee ignores SIGPIPE in case one of the output files is a pipe
  42         * that doesn't consume all its input.  Good idea... */
  43        signal(SIGPIPE, SIG_IGN);
  44
  45        /* Allocate an array of FILE *'s, with one extra for a sentinal. */
  46        fp = files = xzalloc(sizeof(FILE *) * (argc + 2));
  47        np = names = argv - 1;
  48
  49        files[0] = stdout;
  50        goto GOT_NEW_FILE;
  51        do {
  52                *fp = stdout;
  53                if (NOT_LONE_DASH(*argv)) {
  54                        *fp = fopen_or_warn(*argv, mode);
  55                        if (*fp == NULL) {
  56                                retval = EXIT_FAILURE;
  57                                argv++;
  58                                continue;
  59                        }
  60                }
  61                *np = *argv++;
  62 GOT_NEW_FILE:
  63                setbuf(*fp, NULL);      /* tee must not buffer output. */
  64                fp++;
  65                np++;
  66        } while (*argv);
  67        /* names[0] will be filled later */
  68
  69#if ENABLE_FEATURE_TEE_USE_BLOCK_IO
  70        while ((c = safe_read(STDIN_FILENO, buf, sizeof(buf))) > 0) {
  71                fp = files;
  72                do
  73                        fwrite(buf, 1, c, *fp++);
  74                while (*fp);
  75        }
  76        if (c < 0) {            /* Make sure read errors are signaled. */
  77                retval = EXIT_FAILURE;
  78        }
  79#else
  80        setvbuf(stdout, NULL, _IONBF, 0);
  81        while ((c = getchar()) != EOF) {
  82                fp = files;
  83                do
  84                        putc(c, *fp++);
  85                while (*fp);
  86        }
  87#endif
  88
  89        /* Now we need to check for i/o errors on stdin and the various
  90         * output files.  Since we know that the first entry in the output
  91         * file table is stdout, we can save one "if ferror" test by
  92         * setting the first entry to stdin and checking stdout error
  93         * status with fflush_stdout_and_exit()... although fflush()ing
  94         * is unnecessary here. */
  95        np = names;
  96        fp = files;
  97        names[0] = (char *) bb_msg_standard_input;
  98        files[0] = stdin;
  99        do {    /* Now check for input and output errors. */
 100                /* Checking ferror should be sufficient, but we may want to fclose.
 101                 * If we do, remember not to close stdin! */
 102                die_if_ferror(*fp++, *np++);
 103        } while (*fp);
 104
 105        fflush_stdout_and_exit(retval);
 106}
 107