/*
 * 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/getpwnam.c -- "files" backend for nsswitch "passwd" database
 */

#include <pwd.h>
#include <shadow.h>
#include <unistd.h>             /* for PF_PATH */
#include "files_common.h"
#include <strings.h>
#include <stdlib.h>

static uint_t
hash_pwname(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_pwuid(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.uid);

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

        /* uid */
        end = linep;
        id = (uint_t)strtoul(linep, (char **)&end, 10);

        /* empty uid */
        if (linep == end)
                return (UID_NOBODY);

        return (id);
}

static files_hash_func hash_pw[2] = { hash_pwname, hash_pwuid };

static files_hash_t hashinfo = {
        DEFAULTMUTEX,
        sizeof (struct passwd),
        NSS_BUFLEN_PASSWD,
        2,
        hash_pw
};

static int
check_pwname(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_pwname));
}

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

        linep = line;
        limit = line + linelen;

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

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

        /* uid */
        end = linep;
        pw_uid = strtoul(linep, (char **)&end, 10);

        /* check if the uid is empty or overflows */
        if (linep == end || pw_uid > UINT32_MAX)
                return (0);

        return ((uid_t)pw_uid == argp->key.uid);
}

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

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

/*
 * Validates passwd entry replacing uid/gid > MAXUID by ID_NOBODY.
 */
int
validate_passwd_ids(char *line, int *linelenp, int buflen, int extra_chars)
{
        char    *linep, *limit, *uidp, *gidp;
        uid_t   uid;
        gid_t   gid;
        ulong_t uidl, gidl;
        int     olduidlen, oldgidlen, idlen;
        int     linelen = *linelenp, newlinelen;

        /*
         * +name entries in passwd(5) do not override uid and gid
         * values. Therefore no need to validate the ids in these
         * entries.
         */
        if (linelen == 0 || *line == '+' || *line == '-')
                return (NSS_STR_PARSE_SUCCESS);

        linep = line;
        limit = line + linelen;

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

        uidp = linep;
        uidl = strtoul(uidp, (char **)&linep, 10); /* grab uid */
        olduidlen = linep - uidp;
        if (++linep >= limit || olduidlen == 0)
                return (NSS_STR_PARSE_PARSE);

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

        if (uidl <= MAXUID && gidl <= MAXUID)
                return (NSS_STR_PARSE_SUCCESS);
        uid = (uidl > MAXUID) ? UID_NOBODY : (uid_t)uidl;
        gid = (gidl > MAXUID) ? GID_NOBODY : (gid_t)gidl;

        /* Check if we have enough space in the buffer */
        idlen = snprintf(NULL, 0, "%u:%u", uid, gid);
        newlinelen = linelen + idlen - olduidlen - oldgidlen - 1;
        if (newlinelen + extra_chars > buflen)
                return (NSS_STR_PARSE_ERANGE);

        /* Replace ephemeral ids by ID_NOBODY */
        (void) bcopy(linep, uidp + idlen, limit - linep + extra_chars);
        (void) snprintf(uidp, idlen + 1, "%u:%u", uid, gid);
        *(uidp + idlen) = ':'; /* restore : that was overwritten by snprintf */
        *linelenp = newlinelen;
        return (NSS_STR_PARSE_SUCCESS);
}

static files_backend_op_t passwd_ops[] = {
        _nss_files_destr,
        _nss_files_endent,
        _nss_files_setent,
        _nss_files_getent_rigid,
        getbyname,
        getbyuid
};

/*ARGSUSED*/
nss_backend_t *
_nss_files_passwd_constr(dummy1, dummy2, dummy3)
        const char      *dummy1, *dummy2, *dummy3;
{
        return (_nss_files_constr(passwd_ops,
                                sizeof (passwd_ops) / sizeof (passwd_ops[0]),
                                PF_PATH,
                                NSS_LINELEN_PASSWD,
                                &hashinfo));
}