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6486b015fc
This tool changes the default buffering behaviour of standard stdio streams. It only works on dynamic binaries. To make it work for static ones it would require cluttering stdio because there no single entry point. PR: 166660 Reviewed by: current@, jhb Approved by: kib (mentor) MFC after: 1 week
116 lines
3.1 KiB
C
116 lines
3.1 KiB
C
/*-
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* Copyright (c) 2012 Jeremie Le Hen <jlh@FreeBSD.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#include <err.h>
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#include <errno.h>
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#include <limits.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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static const char *
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stream_name(FILE *s)
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{
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if (s == stdin)
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return "stdin";
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if (s == stdout)
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return "stdout";
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if (s == stderr)
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return "stderr";
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/* This should not happen. */
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abort();
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}
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static void
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change_buf(FILE *s, const char *bufmode)
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{
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char *unit;
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size_t bufsize;
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int mode;
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bufsize = 0;
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if (bufmode[0] == '0' && bufmode[1] == '\0')
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mode = _IONBF;
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else if (bufmode[0] == 'L' && bufmode[1] == '\0')
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mode = _IOLBF;
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else if (bufmode[0] == 'B' && bufmode[1] == '\0') {
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mode = _IOFBF;
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bufsize = 0;
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} else {
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/*
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* This library being preloaded, depending on libutil
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* would lead to excessive namespace pollution.
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* Thus we do not use expand_number().
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*/
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errno = 0;
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bufsize = strtol(bufmode, &unit, 0);
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if (errno == EINVAL || errno == ERANGE || unit == bufmode)
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warn("Wrong buffer mode '%s' for %s", bufmode,
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stream_name(s));
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switch (*unit) {
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case 'G':
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bufsize *= 1024 * 1024 * 1024;
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break;
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case 'M':
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bufsize *= 1024 * 1024;
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break;
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case 'k':
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bufsize *= 1024;
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break;
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case '\0':
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break;
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default:
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warnx("Unknown suffix '%c' for %s", *unit,
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stream_name(s));
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return;
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}
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mode = _IOFBF;
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}
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if (setvbuf(s, NULL, mode, bufsize) != 0)
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warn("Cannot set buffer mode '%s' for %s", bufmode,
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stream_name(s));
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}
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__attribute__ ((constructor)) static void
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stdbuf(void)
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{
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char *i_mode, *o_mode, *e_mode;
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i_mode = getenv("_STDBUF_I");
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o_mode = getenv("_STDBUF_O");
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e_mode = getenv("_STDBUF_E");
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if (e_mode != NULL)
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change_buf(stderr, e_mode);
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if (i_mode != NULL)
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change_buf(stdin, i_mode);
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if (o_mode != NULL)
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change_buf(stdout, o_mode);
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}
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