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/* Initgroups handling in nss_db module.
Copyright (C) 2011-2025 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 Library General Public License as
published by the Free Software Foundation; either version 2 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
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If
not, see <https://www.gnu.org/licenses/>. */
#include <ctype.h>
#include <errno.h>
#include <grp.h>
#include <limits.h>
#include <paths.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include <sys/param.h>
#include "nss_db.h"
/* The hashing function we use. */
#include "../intl/hash-string.h"
enum nss_status
_nss_db_initgroups_dyn (const char *user, gid_t group, long int *start,
long int *size, gid_t **groupsp, long int limit,
int *errnop)
{
struct nss_db_map state = { NULL, 0 };
enum nss_status status = internal_setent (_PATH_VARDB "group.db", &state);
if (status != NSS_STATUS_SUCCESS)
{
*errnop = errno;
return status;
}
const struct nss_db_header *header = state.header;
int i;
for (i = 0; i < header->ndbs; ++i)
if (header->dbs[i].id == ':')
break;
if (i == header->ndbs)
{
status = NSS_STATUS_UNAVAIL;
goto out;
}
const stridx_t *hashtable
= (const stridx_t *) ((const char *) header
+ header->dbs[i].hashoffset);
const char *valstrtab = (const char *) header + header->valstroffset;
size_t userlen = strlen (user);
uint32_t hashval = __hash_string (user);
size_t hidx = hashval % header->dbs[i].hashsize;
size_t hval2 = 1 + hashval % (header->dbs[i].hashsize - 2);
gid_t *groups = *groupsp;
status = NSS_STATUS_NOTFOUND;
while (hashtable[hidx] != ~((stridx_t) 0))
{
const char *valstr = valstrtab + hashtable[hidx];
while (isblank (*valstr))
++valstr;
if (strncmp (valstr, user, userlen) == 0 && isblank (valstr[userlen]))
{
valstr += userlen + 1;
while (isblank (*valstr))
++valstr;
while (*valstr != '\0')
{
errno = 0;
char *endp;
unsigned long int n = strtoul (valstr, &endp, 10);
if (*endp != ',' && *endp != '\0')
break;
valstr = *endp == '\0' ? endp : endp + 1;
if (n != ULONG_MAX || errno != ERANGE)
{
/* Insert the group. */
if (*start == *size)
{
/* Need a bigger buffer. */
if (limit > 0 && *size == limit)
{
/* We reached the maximum. */
status = NSS_STATUS_SUCCESS;
goto out;
}
long int newsize;
if (limit <= 0)
newsize = 2 * *size;
else
newsize = MIN (limit, 2 * *size);
gid_t *newgroups = realloc (groups,
newsize * sizeof (*groups));
if (newgroups == NULL)
{
*errnop = ENOMEM;
status = NSS_STATUS_TRYAGAIN;
goto out;
}
*groupsp = groups = newgroups;
*size = newsize;
}
groups[*start] = n;
*start += 1;
}
}
status = NSS_STATUS_SUCCESS;
break;
}
if ((hidx += hval2) >= header->dbs[i].hashsize)
hidx -= header->dbs[i].hashsize;
}
out:
internal_endent (&state);
return status;
}
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