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sortix--sortix/libc/grp/getgrnam.cpp
2013-12-17 14:30:43 +01:00

58 lines
1.8 KiB
C++

/*******************************************************************************
Copyright(C) Jonas 'Sortie' Termansen 2013.
This file is part of the Sortix C Library.
The Sortix 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 3 of the License, or (at your
option) any later version.
The Sortix 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 Sortix C Library. If not, see <http://www.gnu.org/licenses/>.
grp/getgrnam.cpp
Searches the group database for a user with the given groupname in a
thread-insecure manner.
*******************************************************************************/
#include <errno.h>
#include <grp.h>
#include <stdlib.h>
extern "C" struct group* getgrnam(const char* groupname)
{
static struct group result_object;
static char* buf = NULL;
static size_t buflen = 0;
if ( !buf )
{
size_t new_buflen = 64;
if ( !(buf = (char*) malloc(new_buflen)) )
return NULL;
buflen = new_buflen;
}
struct group* result;
retry:
int errnum = getgrnam_r(groupname, &result_object, buf, buflen, &result);
if ( errnum == ERANGE )
{
size_t new_buflen = 2 * buflen;
char* new_buf = (char*) realloc(buf, new_buflen);
if ( !new_buf )
return NULL;
buf = new_buf;
buflen = new_buflen;
goto retry;
}
if ( errnum < 0 )
return errno = errnum, (struct group*) NULL;
return result;
}