source: MondoRescue/branches/3.2/mindi-busybox/coreutils/tee.c@ 3232

/* vi: set sw=4 ts=4: */
/*
 * tee implementation for busybox
 *
 * Copyright (C) 2003  Manuel Novoa III  <mjn3@codepoet.org>
 *
 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
 */

/* BB_AUDIT SUSv3 compliant */
/* http://www.opengroup.org/onlinepubs/007904975/utilities/tee.html */

//usage:#define tee_trivial_usage
//usage:       "[-ai] [FILE]..."
//usage:#define tee_full_usage "\n\n"
//usage:       "Copy stdin to each FILE, and also to stdout\n"
//usage:     "\n    -a  Append to the given FILEs, don't overwrite"
//usage:     "\n    -i  Ignore interrupt signals (SIGINT)"
//usage:
//usage:#define tee_example_usage
//usage:       "$ echo \"Hello\" | tee /tmp/foo\n"
//usage:       "$ cat /tmp/foo\n"
//usage:       "Hello\n"

#include "libbb.h"

int tee_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int tee_main(int argc, char **argv)
{
    const char *mode = "w\0a";
    FILE **files;
    FILE **fp;
    char **names;
    char **np;
    char retval;
//TODO: make unconditional
#if ENABLE_FEATURE_TEE_USE_BLOCK_IO
    ssize_t c;
# define buf bb_common_bufsiz1
#else
    int c;
#endif
    retval = getopt32(argv, "ia");  /* 'a' must be 2nd */
    argc -= optind;
    argv += optind;

    mode += (retval & 2);   /* Since 'a' is the 2nd option... */

    if (retval & 1) {
        signal(SIGINT, SIG_IGN); /* TODO - switch to sigaction. (why?) */
    }
    retval = EXIT_SUCCESS;
    /* gnu tee ignores SIGPIPE in case one of the output files is a pipe
     * that doesn't consume all its input.  Good idea... */
    signal(SIGPIPE, SIG_IGN);

    /* Allocate an array of FILE *'s, with one extra for a sentinel. */
    fp = files = xzalloc(sizeof(FILE *) * (argc + 2));
    np = names = argv - 1;

    files[0] = stdout;
    goto GOT_NEW_FILE;
    do {
        *fp = stdout;
        if (NOT_LONE_DASH(*argv)) {
            *fp = fopen_or_warn(*argv, mode);
            if (*fp == NULL) {
                retval = EXIT_FAILURE;
                argv++;
                continue;
            }
        }
        *np = *argv++;
 GOT_NEW_FILE:
        setbuf(*fp, NULL);  /* tee must not buffer output. */
        fp++;
        np++;
    } while (*argv);
    /* names[0] will be filled later */

#if ENABLE_FEATURE_TEE_USE_BLOCK_IO
    while ((c = safe_read(STDIN_FILENO, buf, sizeof(buf))) > 0) {
        fp = files;
        do
            fwrite(buf, 1, c, *fp);
        while (*++fp);
    }
    if (c < 0) {        /* Make sure read errors are signaled. */
        retval = EXIT_FAILURE;
    }
#else
    setvbuf(stdout, NULL, _IONBF, 0);
    while ((c = getchar()) != EOF) {
        fp = files;
        do
            putc(c, *fp);
        while (*++fp);
    }
#endif

    /* Now we need to check for i/o errors on stdin and the various
     * output files.  Since we know that the first entry in the output
     * file table is stdout, we can save one "if ferror" test by
     * setting the first entry to stdin and checking stdout error
     * status with fflush_stdout_and_exit()... although fflush()ing
     * is unnecessary here. */
    np = names;
    fp = files;
    names[0] = (char *) bb_msg_standard_input;
    files[0] = stdin;
    do {    /* Now check for input and output errors. */
        /* Checking ferror should be sufficient, but we may want to fclose.
         * If we do, remember not to close stdin! */
        die_if_ferror(*fp++, *np++);
    } while (*fp);

    fflush_stdout_and_exit(retval);
}