ngx_open_file_cache.c

来自「Nginx是一个高性能的HTTP和反向代理服务器」· C语言 代码 · 共 820 行 · 第 1/2 页

/*
 * Copyright (C) Igor Sysoev
 */


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_event.h>


/*
 * open file cache caches
 *    open file handles with stat() info;
 *    directories stat() info;
 *    files and directories errors: not found, access denied, etc.
 */


static void ngx_open_file_cache_cleanup(void *data);
static ngx_int_t ngx_open_and_stat_file(u_char *name, ngx_open_file_info_t *of,
    ngx_log_t *log);
static void ngx_open_file_add_event(ngx_open_file_cache_t *cache,
    ngx_cached_open_file_t *file, ngx_open_file_info_t *of, ngx_log_t *log);
static void ngx_open_file_cleanup(void *data);
static void ngx_close_cached_file(ngx_open_file_cache_t *cache,
    ngx_cached_open_file_t *file, ngx_uint_t min_uses, ngx_log_t *log);
static void ngx_open_file_del_event(ngx_cached_open_file_t *file);
static void ngx_expire_old_cached_files(ngx_open_file_cache_t *cache,
    ngx_uint_t n, ngx_log_t *log);
static void ngx_open_file_cache_rbtree_insert_value(ngx_rbtree_node_t *temp,
    ngx_rbtree_node_t *node, ngx_rbtree_node_t *sentinel);
static ngx_cached_open_file_t *
    ngx_open_file_lookup(ngx_open_file_cache_t *cache, ngx_str_t *name,
    uint32_t hash);
static void ngx_open_file_cache_remove(ngx_event_t *ev);


ngx_open_file_cache_t *
ngx_open_file_cache_init(ngx_pool_t *pool, ngx_uint_t max, time_t inactive)
{
    ngx_pool_cleanup_t     *cln;
    ngx_open_file_cache_t  *cache;

    cache = ngx_palloc(pool, sizeof(ngx_open_file_cache_t));
    if (cache == NULL) {
        return NULL;
    }

    ngx_rbtree_init(&cache->rbtree, &cache->sentinel,
                    ngx_open_file_cache_rbtree_insert_value);

    ngx_queue_init(&cache->expire_queue);

    cache->current = 0;
    cache->max = max;
    cache->inactive = inactive;

    cln = ngx_pool_cleanup_add(pool, 0);
    if (cln == NULL) {
        return NULL;
    }

    cln->handler = ngx_open_file_cache_cleanup;
    cln->data = cache;

    return cache;
}


static void
ngx_open_file_cache_cleanup(void *data)
{
    ngx_open_file_cache_t  *cache = data;

    ngx_queue_t             *q;
    ngx_cached_open_file_t  *file;

    ngx_log_debug0(NGX_LOG_DEBUG_CORE, ngx_cycle->log, 0,
                   "open file cache cleanup");

    for ( ;; ) {

        if (ngx_queue_empty(&cache->expire_queue)) {
            break;
        }

        q = ngx_queue_last(&cache->expire_queue);

        file = ngx_queue_data(q, ngx_cached_open_file_t, queue);

        ngx_queue_remove(q);

        ngx_rbtree_delete(&cache->rbtree, &file->node);

        cache->current--;

        ngx_log_debug1(NGX_LOG_DEBUG_CORE, ngx_cycle->log, 0,
                       "delete cached open file: %s", file->name);

        if (!file->err && !file->is_dir) {
            file->close = 1;
            file->count = 0;
            ngx_close_cached_file(cache, file, 0, ngx_cycle->log);

        } else {
            ngx_free(file->name);
            ngx_free(file);
        }
    }

    if (cache->current) {
        ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, 0,
                      "%d items still leave in open file cache",
                      cache->current);
    }

    if (cache->rbtree.root != cache->rbtree.sentinel) {
        ngx_log_error(NGX_LOG_ALERT, ngx_cycle->log, 0,
                      "rbtree still is not empty in open file cache");

    }
}


ngx_int_t
ngx_open_cached_file(ngx_open_file_cache_t *cache, ngx_str_t *name,
    ngx_open_file_info_t *of, ngx_pool_t *pool)
{
    time_t                          now;
    uint32_t                        hash;
    ngx_int_t                       rc;
    ngx_pool_cleanup_t             *cln;
    ngx_cached_open_file_t         *file;
    ngx_pool_cleanup_file_t        *clnf;
    ngx_open_file_cache_cleanup_t  *ofcln;

    of->err = 0;

    if (cache == NULL) {

        cln = ngx_pool_cleanup_add(pool, sizeof(ngx_pool_cleanup_file_t));
        if (cln == NULL) {
            return NGX_ERROR;
        }

        rc = ngx_open_and_stat_file(name->data, of, pool->log);

        if (rc == NGX_OK && !of->is_dir) {
            cln->handler = ngx_pool_cleanup_file;
            clnf = cln->data;

            clnf->fd = of->fd;
            clnf->name = name->data;
            clnf->log = pool->log;
        }

        return rc;
    }

    cln = ngx_pool_cleanup_add(pool, sizeof(ngx_open_file_cache_cleanup_t));
    if (cln == NULL) {
        return NGX_ERROR;
    }

    now = ngx_time();

    hash = ngx_crc32_long(name->data, name->len);

    file = ngx_open_file_lookup(cache, name, hash);

    if (file) {

        file->uses++;

        ngx_queue_remove(&file->queue);

        if (file->fd == NGX_INVALID_FILE && file->err == 0 && !file->is_dir) {

            /* file was not used often enough to keep open */

            rc = ngx_open_and_stat_file(name->data, of, pool->log);

            if (rc != NGX_OK && (of->err == 0 || !of->errors)) {
                goto failed;
            }

            goto add_event;
        }

        if ((file->event && file->use_event)
            || (file->event == NULL && now - file->created < of->valid))
        {
            if (file->err == 0) {

                of->fd = file->fd;
                of->uniq = file->uniq;
                of->mtime = file->mtime;
                of->size = file->size;

                of->is_dir = file->is_dir;
                of->is_file = file->is_file;
                of->is_link = file->is_link;
                of->is_exec = file->is_exec;

                if (!file->is_dir) {
                    file->count++;
                    ngx_open_file_add_event(cache, file, of, pool->log);
                }

            } else {
                of->err = file->err;
            }

            goto found;
        }

        ngx_log_debug4(NGX_LOG_DEBUG_CORE, pool->log, 0,
                       "retest open file: %s, fd:%d, c:%d, e:%d",
                       file->name, file->fd, file->count, file->err);

        if (file->is_dir) {

            /*
             * chances that directory became file are very small
             * so test_dir flag allows to use a single syscall
             * in ngx_file_info() instead of three syscalls
             */

            of->test_dir = 1;
        }

        rc = ngx_open_and_stat_file(name->data, of, pool->log);

        if (rc != NGX_OK && (of->err == 0 || !of->errors)) {
            goto failed;
        }

        if (of->is_dir) {

            if (file->is_dir || file->err) {
                goto update;
            }

            /* file became directory */

        } else if (of->err == 0) {  /* file */

            if (file->is_dir || file->err) {
                goto add_event;
            }

            if (of->uniq == file->uniq
                && of->mtime == file->mtime
                && of->size == file->size)
            {
                if (ngx_close_file(of->fd) == NGX_FILE_ERROR) {
                    ngx_log_error(NGX_LOG_ALERT, pool->log, ngx_errno,
                                  ngx_close_file_n " \"%s\" failed",
                                  name->data);
                }

                of->fd = file->fd;
                file->count++;

                if (file->event) {
                    file->use_event = 1;
                    goto renew;
                }

                ngx_open_file_add_event(cache, file, of, pool->log);

                goto renew;
            }

            /* file was changed */

        } else { /* error to cache */

            if (file->err || file->is_dir) {
                goto update;
            }

            /* file was removed, etc. */
        }

        if (file->count == 0) {

            ngx_open_file_del_event(file);

            if (ngx_close_file(file->fd) == NGX_FILE_ERROR) {
                ngx_log_error(NGX_LOG_ALERT, pool->log, ngx_errno,
                              ngx_close_file_n " \"%s\" failed",
                              name->data);
            }

            goto add_event;
        }

        ngx_rbtree_delete(&cache->rbtree, &file->node);

        cache->current--;

        file->close = 1;

        goto create;
    }

    /* not found */

    rc = ngx_open_and_stat_file(name->data, of, pool->log);

    if (rc != NGX_OK && (of->err == 0 || !of->errors)) {
        goto failed;
    }

create:

    if (cache->current >= cache->max) {
        ngx_expire_old_cached_files(cache, 0, pool->log);
    }

    file = ngx_alloc(sizeof(ngx_cached_open_file_t), pool->log);

    if (file == NULL) {
        goto failed;
    }

    file->name = ngx_alloc(name->len + 1, pool->log);

    if (file->name == NULL) {
        ngx_free(file);
        file = NULL;
        goto failed;
    }

    ngx_cpystrn(file->name, name->data, name->len + 1);

    file->node.key = hash;

    ngx_rbtree_insert(&cache->rbtree, &file->node);

    cache->current++;

    file->uses = 1;
    file->count = 0;
    file->use_event = 0;
    file->event = NULL;

add_event:

    ngx_open_file_add_event(cache, file, of, pool->log);

update:

    file->fd = of->fd;
    file->err = of->err;

    if (of->err == 0) {
        file->uniq = of->uniq;
        file->mtime = of->mtime;
        file->size = of->size;

        file->close = 0;

        file->is_dir = of->is_dir;
        file->is_file = of->is_file;
        file->is_link = of->is_link;
        file->is_exec = of->is_exec;

        if (!of->is_dir) {
            file->count++;
        }
    }

renew:

    file->created = now;

found:

    file->accessed = now;

    ngx_queue_insert_head(&cache->expire_queue, &file->queue);

    ngx_log_debug5(NGX_LOG_DEBUG_CORE, pool->log, 0,
                   "cached open file: %s, fd:%d, c:%d, e:%d, u:%d",
                   file->name, file->fd, file->count, file->err, file->uses);

    if (of->err == 0) {

        if (!of->is_dir) {
            cln->handler = ngx_open_file_cleanup;
            ofcln = cln->data;

            ofcln->cache = cache;
            ofcln->file = file;
            ofcln->min_uses = of->min_uses;
            ofcln->log = pool->log;
        }

        return NGX_OK;
    }

    return NGX_ERROR;

failed:

    if (file) {
        ngx_rbtree_delete(&cache->rbtree, &file->node);