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
  10/* BB_AUDIT SUSv3 compliant */
  11/* http://www.opengroup.org/onlinepubs/007904975/utilities/tee.html */
  12
  13//usage:#define tee_trivial_usage
  14//usage:       "[-ai] [FILE]..."
  15//usage:#define tee_full_usage "\n\n"
  16//usage:       "Copy stdin to each FILE, and also to stdout\n"
  17//usage:     "\n        -a      Append to the given FILEs, don't overwrite"
  18//usage:     "\n        -i      Ignore interrupt signals (SIGINT)"
  19//usage:
  20//usage:#define tee_example_usage
  21//usage:       "$ echo \"Hello\" | tee /tmp/foo\n"
  22//usage:       "$ cat /tmp/foo\n"
  23//usage:       "Hello\n"
  24
  25#include "libbb.h"
  26
  27int tee_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  28int tee_main(int argc, char **argv)
  29{
  30        const char *mode = "w\0a";
  31        FILE **files;
  32        FILE **fp;
  33        char **names;
  34        char **np;
  35        char retval;
  36//TODO: make unconditional
  37#if ENABLE_FEATURE_TEE_USE_BLOCK_IO
  38        ssize_t c;
  39# define buf bb_common_bufsiz1
  40#else
  41        int c;
  42#endif
  43        retval = getopt32(argv, "ia");  /* 'a' must be 2nd */
  44        argc -= optind;
  45        argv += optind;
  46
  47        mode += (retval & 2);   /* Since 'a' is the 2nd option... */
  48
  49        if (retval & 1) {
  50                signal(SIGINT, SIG_IGN); /* TODO - switch to sigaction. (why?) */
  51        }
  52        retval = EXIT_SUCCESS;
  53        /* gnu tee ignores SIGPIPE in case one of the output files is a pipe
  54         * that doesn't consume all its input.  Good idea... */
  55        signal(SIGPIPE, SIG_IGN);
  56
  57        /* Allocate an array of FILE *'s, with one extra for a sentinel. */
  58        fp = files = xzalloc(sizeof(FILE *) * (argc + 2));
  59        np = names = argv - 1;
  60
  61        files[0] = stdout;
  62        goto GOT_NEW_FILE;
  63        do {
  64                *fp = stdout;
  65                if (NOT_LONE_DASH(*argv)) {
  66                        *fp = fopen_or_warn(*argv, mode);
  67                        if (*fp == NULL) {
  68                                retval = EXIT_FAILURE;
  69                                argv++;
  70                                continue;
  71                        }
  72                }
  73                *np = *argv++;
  74 GOT_NEW_FILE:
  75                setbuf(*fp, NULL);      /* tee must not buffer output. */
  76                fp++;
  77                np++;
  78        } while (*argv);
  79        /* names[0] will be filled later */
  80
  81#if ENABLE_FEATURE_TEE_USE_BLOCK_IO
  82        while ((c = safe_read(STDIN_FILENO, buf, sizeof(buf))) > 0) {
  83                fp = files;
  84                do
  85                        fwrite(buf, 1, c, *fp);
  86                while (*++fp);
  87        }
  88        if (c < 0) {            /* Make sure read errors are signaled. */
  89                retval = EXIT_FAILURE;
  90        }
  91#else
  92        setvbuf(stdout, NULL, _IONBF, 0);
  93        while ((c = getchar()) != EOF) {
  94                fp = files;
  95                do
  96                        putc(c, *fp);
  97                while (*++fp);
  98        }
  99#endif
 100
 101        /* Now we need to check for i/o errors on stdin and the various
 102         * output files.  Since we know that the first entry in the output
 103         * file table is stdout, we can save one "if ferror" test by
 104         * setting the first entry to stdin and checking stdout error
 105         * status with fflush_stdout_and_exit()... although fflush()ing
 106         * is unnecessary here. */
 107        np = names;
 108        fp = files;
 109        names[0] = (char *) bb_msg_standard_input;
 110        files[0] = stdin;
 111        do {    /* Now check for input and output errors. */
 112                /* Checking ferror should be sufficient, but we may want to fclose.
 113                 * If we do, remember not to close stdin! */
 114                die_if_ferror(*fp++, *np++);
 115        } while (*fp);
 116
 117        fflush_stdout_and_exit(retval);
 118}
 119