incubator-nuttx/libs/libc/grp/lib_getgrbufr.c

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/****************************************************************************
* libs/libc/grp/lib_getgrbufr.c
*
* SPDX-License-Identifier: Apache-2.0
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <grp.h>
#include "grp/lib_grp.h"
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: getgrbuf_r
*
* Description:
* libc/grp internal helper function for getgrgid_r and getgrnam_r to setup
* the caller supplied 'grp' and 'buf' buffers once a matching entry has
* been found.
*
* Input Parameters:
* gid - Value to set grp->gr_gid to.
* name - Value to set grp->gr_name to.
* passwd - Value to set grp->passwd to.
* grp - Pointer to the space to store the retrieved group structure in.
* buf - String fields pointed to by the group struct are stored here.
* buflen - The length of buf in bytes.
* result - Pointer to the resulting group struct, or NULL in case of fail.
*
* Returned Value:
* On success getgrgid_r returns 0 and sets *result to grp. In case of
* failure an error number is returned.
*
****************************************************************************/
int getgrbuf_r(gid_t gid, FAR const char *name, FAR const char *passwd,
FAR struct group *grp, FAR char *buf, size_t buflen,
FAR struct group **result)
{
size_t reqdlen;
size_t padlen;
size_t namesize;
size_t passwdsize;
/* In 'buf' a NULL pointer value will be stored, which must be naturally
* aligned, followed by the null terminated group name string and the null
* terminated passwd string 'x' (indicating 'no password'). Make sure
* sufficient buffer space was supplied by the caller.
*/
namesize = strlen(name) + 1;
passwdsize = strlen(passwd) + 1;
padlen = sizeof(FAR void *) - ((uintptr_t)buf % sizeof(FAR char *));
reqdlen = sizeof(FAR void *) + namesize + passwdsize;
if (buflen < padlen + reqdlen)
{
/* Insufficient buffer space supplied. */
*result = NULL;
return ERANGE;
}
grp->gr_mem = (FAR char **)&buf[padlen];
grp->gr_name = &buf[padlen + sizeof(FAR char *)];
grp->gr_passwd = &buf[padlen + sizeof(FAR char *) + namesize];
strlcpy(grp->gr_name, name, namesize);
strlcpy(grp->gr_passwd, passwd, passwdsize);
grp->gr_gid = gid;
*grp->gr_mem = NULL;
*result = grp;
return 0;
}