/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2008, 2009 Edward Tomasz Napierała <trasz@FreeBSD.org>
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <assert.h>
#include <string.h>
#include <pwd.h>
#include <grp.h>
#include <sys/syscall.h>
#include <sys/types.h>
#include <sys/acl.h>

#include "acl_support.h"

#define MAX_ENTRY_LENGTH 512

static int
format_who(char *str, size_t size, const acl_entry_t entry, int numeric)
{
        int error;
        acl_tag_t tag;
        struct passwd *pwd;
        struct group *grp;
        uid_t *id;

        error = acl_get_tag_type(entry, &tag);
        if (error)
                return (error);

        switch (tag) {
        case ACL_USER_OBJ:
                snprintf(str, size, "owner@");
                break;

        case ACL_USER:
                id = (uid_t *)acl_get_qualifier(entry);
                if (id == NULL)
                        return (-1);
                /* XXX: Thread-unsafe. */
                if (!numeric)
                        pwd = getpwuid(*id);
                else
                        pwd = NULL;
                if (pwd == NULL)
                        snprintf(str, size, "user:%d", (unsigned int)*id);
                else
                        snprintf(str, size, "user:%s", pwd->pw_name);
                acl_free(id);
                break;

        case ACL_GROUP_OBJ:
                snprintf(str, size, "group@");
                break;

        case ACL_GROUP:
                id = (uid_t *)acl_get_qualifier(entry);
                if (id == NULL)
                        return (-1);
                /* XXX: Thread-unsafe. */
                if (!numeric)
                        grp = getgrgid(*id);
                else
                        grp = NULL;
                if (grp == NULL)
                        snprintf(str, size, "group:%d", (unsigned int)*id);
                else
                        snprintf(str, size, "group:%s", grp->gr_name);
                acl_free(id);
                break;

        case ACL_EVERYONE:
                snprintf(str, size, "everyone@");
                break;

        default:
                return (-1);
        }

        return (0);
}

static int
format_entry_type(char *str, size_t size, const acl_entry_t entry)
{
        int error;
        acl_entry_type_t entry_type;

        error = acl_get_entry_type_np(entry, &entry_type);
        if (error)
                return (error);

        switch (entry_type) {
        case ACL_ENTRY_TYPE_ALLOW:
                snprintf(str, size, "allow");
                break;
        case ACL_ENTRY_TYPE_DENY:
                snprintf(str, size, "deny");
                break;
        case ACL_ENTRY_TYPE_AUDIT:
                snprintf(str, size, "audit");
                break;
        case ACL_ENTRY_TYPE_ALARM:
                snprintf(str, size, "alarm");
                break;
        default:
                return (-1);
        }

        return (0);
}

static int
format_additional_id(char *str, size_t size, const acl_entry_t entry)
{
        int error;
        acl_tag_t tag;
        uid_t *id;

        error = acl_get_tag_type(entry, &tag);
        if (error)
                return (error);

        switch (tag) {
        case ACL_USER_OBJ:
        case ACL_GROUP_OBJ:
        case ACL_EVERYONE:
                str[0] = '\0';
                break;

        default:
                id = (uid_t *)acl_get_qualifier(entry);
                if (id == NULL)
                        return (-1);
                snprintf(str, size, ":%d", (unsigned int)*id);
                acl_free(id);
        }

        return (0);
}

static int
format_entry(char *str, size_t size, const acl_entry_t entry, int flags)
{
        size_t off = 0, min_who_field_length = 18;
        acl_permset_t permset;
        acl_flagset_t flagset;
        int error, len;
        char buf[MAX_ENTRY_LENGTH + 1];

        assert(_entry_brand(entry) == ACL_BRAND_NFS4);

        error = acl_get_flagset_np(entry, &flagset);
        if (error)
                return (error);

        error = acl_get_permset(entry, &permset);
        if (error)
                return (error);

        error = format_who(buf, sizeof(buf), entry,
            flags & ACL_TEXT_NUMERIC_IDS);
        if (error)
                return (error);
        len = strlen(buf);
        if (len < min_who_field_length)
                len = min_who_field_length;
        off += snprintf(str + off, size - off, "%*s:", len, buf);

        error = _nfs4_format_access_mask(buf, sizeof(buf), *permset,
            flags & ACL_TEXT_VERBOSE);
        if (error)
                return (error);
        off += snprintf(str + off, size - off, "%s:", buf);

        error = _nfs4_format_flags(buf, sizeof(buf), *flagset,
            flags & ACL_TEXT_VERBOSE);
        if (error)
                return (error);
        off += snprintf(str + off, size - off, "%s:", buf);

        error = format_entry_type(buf, sizeof(buf), entry);
        if (error)
                return (error);
        off += snprintf(str + off, size - off, "%s", buf);

        if (flags & ACL_TEXT_APPEND_ID) {
                error = format_additional_id(buf, sizeof(buf), entry);
                if (error)
                        return (error);
                off += snprintf(str + off, size - off, "%s", buf);
        }

        off += snprintf(str + off, size - off, "\n");

        /* Make sure we didn't truncate anything. */
        assert (off < size);

        return (0);
}

char *
_nfs4_acl_to_text_np(const acl_t aclp, ssize_t *len_p, int flags)
{
        int error, off = 0, size, entry_id = ACL_FIRST_ENTRY;
        char *str;
        acl_entry_t entry;

        if (aclp->ats_acl.acl_cnt == 0)
                return strdup("");

        size = aclp->ats_acl.acl_cnt * MAX_ENTRY_LENGTH;
        str = malloc(size);
        if (str == NULL)
                return (NULL);

        while (acl_get_entry(aclp, entry_id, &entry) == 1) {
                entry_id = ACL_NEXT_ENTRY;

                assert(off < size);

                error = format_entry(str + off, size - off, entry, flags);
                if (error) {
                        free(str);
                        errno = EINVAL;
                        return (NULL);
                }

                off = strlen(str);
        }

        assert(off < size);
        str[off] = '\0';

        if (len_p != NULL)
                *len_p = off;

        return (str);
}