files/common/getgrent.c

/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 *
 * files/getgrent.c -- "files" backend for nsswitch "group" database
 */

#include <grp.h>
#include <unistd.h>     /* for GF_PATH */
#include <stdlib.h>     /* for GF_PATH */
#include "files_common.h"
#include <strings.h>

static uint_t
hash_grname(nss_XbyY_args_t *argp, int keyhash, const char *line,
    int linelen)
{
    const char  *name;
    int     namelen, i;
    uint_t      hash = 0;

    if (keyhash) {
        name = argp->key.name;
        namelen = strlen(name);
    } else {
        name = line;
        namelen = 0;
        while (linelen-- && *line++ != ':')
            namelen++;
    }

    for (i = 0; i < namelen; i++)
        hash = hash * 15 + name[i];
    return (hash);
}

static uint_t
hash_grgid(nss_XbyY_args_t *argp, int keyhash, const char *line,
    int linelen)
{
    uint_t      id;
    const char  *linep, *limit, *end;

    linep = line;
    limit = line + linelen;

    if (keyhash)
        return ((uint_t)argp->key.gid);

    while (linep < limit && *linep++ != ':') /* skip groupname */
        continue;
    while (linep < limit && *linep++ != ':') /* skip password */
        continue;
    if (linep == limit)
        return (GID_NOBODY);

    /* gid */
    end = linep;
    id = (uint_t)strtoul(linep, (char **)&end, 10);
    /* empty gid */
    if (linep == end)
        return (GID_NOBODY);

    return (id);
}

static files_hash_func hash_gr[2] = { hash_grname, hash_grgid };

static files_hash_t hashinfo = {
    DEFAULTMUTEX,
    sizeof (struct group),
    NSS_BUFLEN_GROUP,
    2,
    hash_gr
};

static int
check_grname(nss_XbyY_args_t *argp, const char *line, int linelen)
{
    const char *linep, *limit;
    const char *keyp = argp->key.name;

    linep = line;
    limit = line + linelen;

    /* +/- entries valid for compat source only */
    if (linelen == 0 || *line == '+' || *line == '-')
        return (0);
    while (*keyp && linep < limit && *keyp == *linep) {
        keyp++;
        linep++;
    }
    return (linep < limit && *keyp == '\0' && *linep == ':');
}

static nss_status_t
getbyname(be, a)
    files_backend_ptr_t be;
    void            *a;
{
    return (_nss_files_XY_hash(be, a, 0, &hashinfo, 0, check_grname));
}

static int
check_grgid(nss_XbyY_args_t *argp, const char *line, int linelen)
{
    const char  *linep, *limit, *end;
    ulong_t     gr_gid;

    linep = line;
    limit = line + linelen;

    /* +/- entries valid for compat source only */
    if (linelen == 0 || *line == '+' || *line == '-')
        return (0);

    while (linep < limit && *linep++ != ':') /* skip groupname */
        continue;
    while (linep < limit && *linep++ != ':') /* skip password */
        continue;
    if (linep == limit)
        return (0);

    /* gid */
    end = linep;
    gr_gid = strtoul(linep, (char **)&end, 10);

    /* check if gid is empty or overflows */
    if (linep == end || gr_gid > UINT32_MAX)
        return (0);

    return ((gid_t)gr_gid == argp->key.gid);
}

static nss_status_t
getbygid(be, a)
    files_backend_ptr_t be;
    void            *a;
{
    nss_XbyY_args_t *argp = (nss_XbyY_args_t *)a;

    if (argp->key.gid > MAXUID)
        return (NSS_NOTFOUND);
    return (_nss_files_XY_hash(be, argp, 0, &hashinfo, 1, check_grgid));
}

/*
 * Validates group entry replacing gid > MAXUID by GID_NOBODY.
 */
int
validate_group_ids(char *line, int *linelenp, int buflen, int extra_chars,
        files_XY_check_func check)
{
    char    *linep, *limit, *gidp;
    ulong_t gid;
    int oldgidlen, idlen;
    int linelen = *linelenp, newlinelen;

    /*
     * getbygid() rejects searching by ephemeral gid therefore
     * no need to validate because the matched entry won't have
     * an ephemeral gid.
     */
    if (check != NULL && check == check_grgid)
        return (NSS_STR_PARSE_SUCCESS);

    /* +/- entries valid for compat source only */
    if (linelen == 0 || *line == '+' || *line == '-')
        return (NSS_STR_PARSE_SUCCESS);

    linep = line;
    limit = line + linelen;

    while (linep < limit && *linep++ != ':') /* skip groupname */
        continue;
    while (linep < limit && *linep++ != ':') /* skip password */
        continue;
    if (linep == limit)
        return (NSS_STR_PARSE_PARSE);

    gidp = linep;
    gid = strtoul(gidp, (char **)&linep, 10); /* grab gid */
    oldgidlen = linep - gidp;
    if (linep >= limit || oldgidlen == 0)
        return (NSS_STR_PARSE_PARSE);

    if (gid <= MAXUID)
        return (NSS_STR_PARSE_SUCCESS);

    idlen = snprintf(NULL, 0, "%u", GID_NOBODY);
    newlinelen = linelen + idlen - oldgidlen;
    if (newlinelen + extra_chars > buflen)
        return (NSS_STR_PARSE_ERANGE);

    (void) bcopy(linep, gidp + idlen, limit - linep + extra_chars);
    (void) snprintf(gidp, idlen + 1, "%u", GID_NOBODY);
    *(gidp + idlen) = ':';
    *linelenp = newlinelen;
    return (NSS_STR_PARSE_SUCCESS);
}

static nss_status_t
getbymember(be, a)
    files_backend_ptr_t be;
    void            *a;
{
    struct nss_groupsbymem  *argp = (struct nss_groupsbymem *)a;

    return (_nss_files_do_all(be, argp, argp->username,
                (files_do_all_func_t)argp->process_cstr));
}

static files_backend_op_t group_ops[] = {
    _nss_files_destr,
    _nss_files_endent,
    _nss_files_setent,
    _nss_files_getent_rigid,
    getbyname,
    getbygid,
    getbymember
};

/*ARGSUSED*/
nss_backend_t *
_nss_files_group_constr(dummy1, dummy2, dummy3)
    const char  *dummy1, *dummy2, *dummy3;
{
    return (_nss_files_constr(group_ops,
                sizeof (group_ops) / sizeof (group_ops[0]),
                GF_PATH,
                NSS_LINELEN_GROUP,
                &hashinfo));
}