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

112 lines
4.2 KiB
C

/****************************************************************************
* libs/libc/grp/lib_getgrbufr.c
*
* Copyright (C) 2019 Gregory Nutt. All rights reserved.
* Author: Michael Jung <mijung@gmx.net>
*
* 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.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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
* COPYRIGHT OWNER 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.
*
****************************************************************************/
/****************************************************************************
* 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;
/* 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.
*/
padlen = sizeof(FAR void *) - ((uintptr_t)buf % sizeof(FAR char *));
reqdlen = sizeof(FAR void *) + strlen(name) + 1 + strlen(passwd) + 1;
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 *) + strlen(name) + 1];
strcpy(grp->gr_name, name);
strcpy(grp->gr_passwd, passwd);
grp->gr_gid = gid;
*grp->gr_mem = NULL;
*result = grp;
return 0;
}