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/* Copyright (C) 1991-2016 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <errno.h>
#include <grp.h>
#include <libc-lock.h>
#include <stdio.h>
#include <stdlib.h>
/* We need to protect the dynamic buffer handling. */
__libc_lock_define_initialized (static, lock);
libc_freeres_ptr (static char *buffer);
/* Read one entry from the given stream. */
struct group *
fgetgrent (FILE *stream)
{
static size_t buffer_size;
static struct group resbuf;
fpos_t pos;
struct group *result;
int save;
if (__builtin_expect (fgetpos (stream, &pos), 0) != 0)
return NULL;
/* Get lock. */
__libc_lock_lock (lock);
/* Allocate buffer if not yet available. */
if (buffer == NULL)
{
buffer_size = NSS_BUFLEN_GROUP;
buffer = malloc (buffer_size);
}
while (buffer != NULL
&& (__fgetgrent_r (stream, &resbuf, buffer, buffer_size, &result)
== ERANGE))
{
char *new_buf;
buffer_size += NSS_BUFLEN_GROUP;
new_buf = realloc (buffer, buffer_size);
if (__glibc_unlikely (new_buf == NULL))
{
/* We are out of memory. Free the current buffer so that the
process gets a chance for a normal termination. */
save = errno;
free (buffer);
__set_errno (save);
}
buffer = new_buf;
/* Reset the stream. */
if (fsetpos (stream, &pos) != 0)
buffer = NULL;
}
if (buffer == NULL)
result = NULL;
/* Release lock. Preserve error value. */
save = errno;
__libc_lock_unlock (lock);
__set_errno (save);
return result;
}
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