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/*
* libcompat - system compatibility library
*
* Copyright © 1995 Ian Jackson <ijackson@chiark.greenend.org.uk>
* Copyright © 2008-2012 Guillem Jover <guillem@debian.org>
*
* This is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
#include <config.h>
#include <sys/types.h>
#include <unistd.h>
#include <stdarg.h>
#include <stdio.h>
#include "compat.h"
int
vsnprintf(char *buf, size_t maxsize, const char *fmt, va_list args)
{
static FILE *file = NULL;
static pid_t file_pid;
size_t want, nr;
int total;
if (maxsize != 0 && buf == NULL)
return -1;
/* Avoid race conditions from children after a fork(2). */
if (file_pid > 0 && file_pid != getpid()) {
fclose(file);
file = NULL;
}
if (!file) {
file = tmpfile();
if (!file)
return -1;
file_pid = getpid();
} else {
if (fseek(file, 0, 0))
return -1;
if (ftruncate(fileno(file), 0))
return -1;
}
total = vfprintf(file, fmt, args);
if (total < 0)
return -1;
if (maxsize == 0)
return total;
if (total >= (int)maxsize)
want = maxsize - 1;
else
want = total;
if (fflush(file))
return -1;
if (fseek(file, 0, SEEK_SET))
return -1;
nr = fread(buf, 1, want, file);
if (nr != want)
return -1;
buf[want] = '\0';
return total;
}
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