upcall_cache.c

来自「lustre 1.6.5 source code」· C语言 代码 · 共 519 行 · 第 1/2 页

/* -*- mode: c; c-basic-offset: 8; indent-tabs-mode: nil; -*-
 * vim:expandtab:shiftwidth=8:tabstop=8:
 *
 *  Supplementary groups cache.
 *
 *  Copyright (c) 2004 Cluster File Systems, Inc.
 *
 *   This file is part of Lustre, http://www.lustre.org.
 *
 *   Lustre is free software; you can redistribute it and/or
 *   modify it under the terms of version 2 of the GNU General Public
 *   License as published by the Free Software Foundation.
 *
 *   Lustre 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 General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with Lustre; if not, write to the Free Software
 *   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#define DEBUG_SUBSYSTEM S_SEC

#ifndef AUTOCONF_INCLUDED
#include <linux/config.h>
#endif
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/kmod.h>
#include <linux/string.h>
#include <linux/stat.h>
#include <linux/errno.h>
#include <linux/version.h>
#include <linux/unistd.h>

#include <asm/system.h>
#include <asm/uaccess.h>

#include <linux/fs.h>
#include <linux/stat.h>
#include <asm/uaccess.h>
#include <linux/slab.h>

#include <obd_support.h>
#include <lustre_lib.h>

#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,4)
struct group_info *groups_alloc(int ngroups)
{
        struct group_info *ginfo;

        LASSERT(ngroups <= NGROUPS_SMALL);

        OBD_ALLOC(ginfo, sizeof(*ginfo) + 1 * sizeof(gid_t *));
        if (!ginfo)
                return NULL;
        ginfo->ngroups = ngroups;
        ginfo->nblocks = 1;
        ginfo->blocks[0] = ginfo->small_block;
        atomic_set(&ginfo->usage, 1);

        return ginfo;
}

void groups_free(struct group_info *ginfo)
{
        LASSERT(ginfo->ngroups <= NGROUPS_SMALL);
        LASSERT(ginfo->nblocks == 1);
        LASSERT(ginfo->blocks[0] == ginfo->small_block);

        OBD_FREE(ginfo, sizeof(*ginfo) + 1 * sizeof(gid_t *));
}
#endif

static struct upcall_cache_entry *alloc_entry(__u64 key)
{
        struct upcall_cache_entry *entry;

        OBD_ALLOC(entry, sizeof(*entry));
        if (!entry)
                return NULL;

        UC_CACHE_SET_NEW(entry);
        INIT_LIST_HEAD(&entry->ue_hash);
        entry->ue_key = key;
        atomic_set(&entry->ue_refcount, 0);
        init_waitqueue_head(&entry->ue_waitq);
        return entry;
}

/* protected by hash lock */
static void free_entry(struct upcall_cache_entry *entry)
{
        if (entry->ue_group_info)
                groups_free(entry->ue_group_info);
        list_del(&entry->ue_hash);
        CDEBUG(D_OTHER, "destroy cache entry %p for key "LPU64"\n",
               entry, entry->ue_key);
        OBD_FREE(entry, sizeof(*entry));
}

static void get_entry(struct upcall_cache_entry *entry)
{
        atomic_inc(&entry->ue_refcount);
}

static void put_entry(struct upcall_cache_entry *entry)
{
        if (atomic_dec_and_test(&entry->ue_refcount) &&
            (UC_CACHE_IS_INVALID(entry) || UC_CACHE_IS_EXPIRED(entry))) {
                free_entry(entry);
        }
}

static int check_unlink_entry(struct upcall_cache_entry *entry)
{
        if (UC_CACHE_IS_VALID(entry) &&
            time_before(jiffies, entry->ue_expire))
                return 0;

        if (UC_CACHE_IS_ACQUIRING(entry)) {
                if (time_before(jiffies, entry->ue_acquire_expire))
                        return 0;

                UC_CACHE_SET_EXPIRED(entry);
                wake_up_all(&entry->ue_waitq);
        } else if (!UC_CACHE_IS_INVALID(entry)) {
                UC_CACHE_SET_EXPIRED(entry);
        }

        list_del_init(&entry->ue_hash);
        if (!atomic_read(&entry->ue_refcount))
                free_entry(entry);
        return 1;
}

static int refresh_entry(struct upcall_cache *hash,
                         struct upcall_cache_entry *entry)
{
        char *argv[4];
        char *envp[3];
        char keystr[16];
        int rc;
        ENTRY;

        snprintf(keystr, 16, LPU64, entry->ue_key);

        CDEBUG(D_INFO, "The groups upcall is: %s \n", hash->uc_upcall);
        argv[0] = hash->uc_upcall;
        argv[1] = hash->uc_name;
        argv[2] = keystr;
        argv[3] = NULL;

        envp[0] = "HOME=/";
        envp[1] = "PATH=/sbin:/usr/sbin";
        envp[2] = NULL;

        rc = USERMODEHELPER(argv[0], argv, envp);
        if (rc < 0) {
                CERROR("%s: error invoking getgroups upcall %s %s %s: rc %d; "
                       "check /proc/fs/lustre/mds/%s/group_upcall\n",
                       hash->uc_name, argv[0], argv[1], argv[2], rc, argv[1]);
        } else {
                CDEBUG(D_HA, "%s: invoked upcall %s %s %s\n", hash->uc_name,
                       argv[0], argv[1], argv[2]);
                rc = 0;
        }
        RETURN(rc);
}

static int entry_set_group_info(struct upcall_cache_entry *entry, __u32 primary,
                                __u32 ngroups, __u32 *groups)
{
        struct group_info *ginfo;
        int i, j;
        ENTRY;

#if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,4)
        if (ngroups > NGROUPS)
                ngroups = NGROUPS;
#endif

        if (ngroups > NGROUPS_MAX) {
                CERROR("using first %d supplementary groups for uid "LPU64"\n",
                       NGROUPS_MAX, entry->ue_key);
                ngroups = NGROUPS_MAX;
        }

        ginfo = groups_alloc(ngroups);
        if (!ginfo) {
                CERROR("uid "LPU64" update can't alloc ginfo for %d groups\n",
                       entry->ue_key, ngroups);
                RETURN(-ENOMEM);
        }
        entry->ue_group_info = ginfo;
        entry->ue_primary = primary;

        for (i = 0; i < ginfo->nblocks; i++) {
                int cp_count = min(NGROUPS_PER_BLOCK, (int)ngroups);
                int off = i * NGROUPS_PER_BLOCK;

                for (j = 0; j < cp_count; j++)
                        ginfo->blocks[i][j] = groups[off + j];

                ngroups -= cp_count;
        }
        RETURN(0);
}

struct upcall_cache_entry *upcall_cache_get_entry(struct upcall_cache *hash,
                                                  __u64 key, __u32 primary,
                                                  __u32 ngroups, __u32 *groups)
{
        struct upcall_cache_entry *entry = NULL, *new = NULL, *next;
        struct list_head *head;
        wait_queue_t wait;
        int rc, found;
        ENTRY;

        LASSERT(hash);

        if (strcmp(hash->uc_upcall, "NONE") == 0) {
                new = alloc_entry(key);
                if (!new) {
                        CERROR("fail to alloc entry\n");
                        RETURN(NULL);
                }
                get_entry(new);

                /* We have to sort the groups for 2.6 kernels */
                LASSERT(ngroups <= 2);
                if (ngroups == 2 && groups[1] == -1)
                        ngroups--;
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,4)
                /* 2.6 needs groups array sorted */
                if (ngroups == 2 && groups[0] > groups[1]) {
                        __u32 tmp = groups[1];
                        groups[1] = groups[0];
                        groups[0] = tmp;
                }
#endif
                if (ngroups > 0 && groups[0] == -1) {
                        groups[0] = groups[1];
                        ngroups--;
                }

                rc = entry_set_group_info(new, primary, ngroups, groups);

                /* We can't cache this entry as it only has a subset of
                 * the user's groups, as sent in suppgid1, suppgid2. */
                UC_CACHE_SET_EXPIRED(new);
                RETURN(new);
        }
        head = &hash->uc_hashtable[UC_CACHE_HASH_INDEX(key)];
find_again:
        found = 0;
        spin_lock(&hash->uc_lock);