freebsd-dev/lib/libstdbuf/stdbuf.c

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