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view src/http/ngx_http_copy_filter_module.c @ 6768:d9c180fcbfa7 stable-1.10

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Event pipe: do not set file's thread_handler if not needed. This fixes a problem with aio threads and sendfile with aio_write switched off, as observed with range requests after fc72784b1f52 (1.9.13). Potential problems with sendfile in threads were previously described in 9fd738b85fad, and this seems to be one of them. The problem occurred as file's thread_handler was set to NULL by event pipe code after a sendfile thread task was scheduled. As a result, no sendfile completion code was executed, and the same buffer was additionally sent using non-threaded sendfile. Fix is to avoid modifying file's thread_handler if aio_write is switched off. Note that with "aio_write on" it is still possible that sendfile will use thread_handler as set by event pipe. This is believed to be safe though, as handlers used are compatible.
author Maxim Dounin <mdounin@mdounin.ru>
date Thu, 01 Sep 2016 20:05:23 +0300
parents c5f81dcf97a7
children ce37362a7a70
line wrap: on
line source


/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


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


typedef struct {
    ngx_bufs_t  bufs;
} ngx_http_copy_filter_conf_t;


#if (NGX_HAVE_FILE_AIO)
static void ngx_http_copy_aio_handler(ngx_output_chain_ctx_t *ctx,
    ngx_file_t *file);
static void ngx_http_copy_aio_event_handler(ngx_event_t *ev);
#if (NGX_HAVE_AIO_SENDFILE)
static ssize_t ngx_http_copy_aio_sendfile_preload(ngx_buf_t *file);
static void ngx_http_copy_aio_sendfile_event_handler(ngx_event_t *ev);
#endif
#endif
#if (NGX_THREADS)
static ngx_int_t ngx_http_copy_thread_handler(ngx_thread_task_t *task,
    ngx_file_t *file);
static void ngx_http_copy_thread_event_handler(ngx_event_t *ev);
#endif

static void *ngx_http_copy_filter_create_conf(ngx_conf_t *cf);
static char *ngx_http_copy_filter_merge_conf(ngx_conf_t *cf,
    void *parent, void *child);
static ngx_int_t ngx_http_copy_filter_init(ngx_conf_t *cf);


static ngx_command_t  ngx_http_copy_filter_commands[] = {

    { ngx_string("output_buffers"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE2,
      ngx_conf_set_bufs_slot,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_http_copy_filter_conf_t, bufs),
      NULL },

      ngx_null_command
};


static ngx_http_module_t  ngx_http_copy_filter_module_ctx = {
    NULL,                                  /* preconfiguration */
    ngx_http_copy_filter_init,             /* postconfiguration */

    NULL,                                  /* create main configuration */
    NULL,                                  /* init main configuration */

    NULL,                                  /* create server configuration */
    NULL,                                  /* merge server configuration */

    ngx_http_copy_filter_create_conf,      /* create location configuration */
    ngx_http_copy_filter_merge_conf        /* merge location configuration */
};


ngx_module_t  ngx_http_copy_filter_module = {
    NGX_MODULE_V1,
    &ngx_http_copy_filter_module_ctx,      /* module context */
    ngx_http_copy_filter_commands,         /* module directives */
    NGX_HTTP_MODULE,                       /* module type */
    NULL,                                  /* init master */
    NULL,                                  /* init module */
    NULL,                                  /* init process */
    NULL,                                  /* init thread */
    NULL,                                  /* exit thread */
    NULL,                                  /* exit process */
    NULL,                                  /* exit master */
    NGX_MODULE_V1_PADDING
};


static ngx_http_output_body_filter_pt    ngx_http_next_body_filter;


static ngx_int_t
ngx_http_copy_filter(ngx_http_request_t *r, ngx_chain_t *in)
{
    ngx_int_t                     rc;
    ngx_connection_t             *c;
    ngx_output_chain_ctx_t       *ctx;
    ngx_http_core_loc_conf_t     *clcf;
    ngx_http_copy_filter_conf_t  *conf;

    c = r->connection;

    ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0,
                   "http copy filter: \"%V?%V\"", &r->uri, &r->args);

    ctx = ngx_http_get_module_ctx(r, ngx_http_copy_filter_module);

    if (ctx == NULL) {
        ctx = ngx_pcalloc(r->pool, sizeof(ngx_output_chain_ctx_t));
        if (ctx == NULL) {
            return NGX_ERROR;
        }

        ngx_http_set_ctx(r, ctx, ngx_http_copy_filter_module);

        conf = ngx_http_get_module_loc_conf(r, ngx_http_copy_filter_module);
        clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);

        ctx->sendfile = c->sendfile;
        ctx->need_in_memory = r->main_filter_need_in_memory
                              || r->filter_need_in_memory;
        ctx->need_in_temp = r->filter_need_temporary;

        ctx->alignment = clcf->directio_alignment;

        ctx->pool = r->pool;
        ctx->bufs = conf->bufs;
        ctx->tag = (ngx_buf_tag_t) &ngx_http_copy_filter_module;

        ctx->output_filter = (ngx_output_chain_filter_pt)
                                  ngx_http_next_body_filter;
        ctx->filter_ctx = r;

#if (NGX_HAVE_FILE_AIO)
        if (ngx_file_aio && clcf->aio == NGX_HTTP_AIO_ON) {
            ctx->aio_handler = ngx_http_copy_aio_handler;
#if (NGX_HAVE_AIO_SENDFILE)
            ctx->aio_preload = ngx_http_copy_aio_sendfile_preload;
#endif
        }
#endif

#if (NGX_THREADS)
        if (clcf->aio == NGX_HTTP_AIO_THREADS) {
            ctx->thread_handler = ngx_http_copy_thread_handler;
        }
#endif

        if (in && in->buf && ngx_buf_size(in->buf)) {
            r->request_output = 1;
        }
    }

#if (NGX_HAVE_FILE_AIO || NGX_THREADS)
    ctx->aio = r->aio;
#endif

    rc = ngx_output_chain(ctx, in);

    if (ctx->in == NULL) {
        r->buffered &= ~NGX_HTTP_COPY_BUFFERED;

    } else {
        r->buffered |= NGX_HTTP_COPY_BUFFERED;
    }

    ngx_log_debug3(NGX_LOG_DEBUG_HTTP, c->log, 0,
                   "http copy filter: %i \"%V?%V\"", rc, &r->uri, &r->args);

    return rc;
}


#if (NGX_HAVE_FILE_AIO)

static void
ngx_http_copy_aio_handler(ngx_output_chain_ctx_t *ctx, ngx_file_t *file)
{
    ngx_http_request_t *r;

    r = ctx->filter_ctx;

    file->aio->data = r;
    file->aio->handler = ngx_http_copy_aio_event_handler;

    r->main->blocked++;
    r->aio = 1;
    ctx->aio = 1;
}


static void
ngx_http_copy_aio_event_handler(ngx_event_t *ev)
{
    ngx_event_aio_t     *aio;
    ngx_http_request_t  *r;

    aio = ev->data;
    r = aio->data;

    r->main->blocked--;
    r->aio = 0;

    r->connection->write->handler(r->connection->write);
}


#if (NGX_HAVE_AIO_SENDFILE)

static ssize_t
ngx_http_copy_aio_sendfile_preload(ngx_buf_t *file)
{
    ssize_t                  n;
    static u_char            buf[1];
    ngx_event_aio_t         *aio;
    ngx_http_request_t      *r;
    ngx_output_chain_ctx_t  *ctx;

    n = ngx_file_aio_read(file->file, buf, 1, file->file_pos, NULL);

    if (n == NGX_AGAIN) {
        aio = file->file->aio;
        aio->handler = ngx_http_copy_aio_sendfile_event_handler;

        r = aio->data;
        r->main->blocked++;
        r->aio = 1;

        ctx = ngx_http_get_module_ctx(r, ngx_http_copy_filter_module);
        ctx->aio = 1;
    }

    return n;
}


static void
ngx_http_copy_aio_sendfile_event_handler(ngx_event_t *ev)
{
    ngx_event_aio_t     *aio;
    ngx_http_request_t  *r;

    aio = ev->data;
    r = aio->data;

    r->main->blocked--;
    r->aio = 0;
    ev->complete = 0;

    r->connection->write->handler(r->connection->write);
}

#endif
#endif


#if (NGX_THREADS)

static ngx_int_t
ngx_http_copy_thread_handler(ngx_thread_task_t *task, ngx_file_t *file)
{
    ngx_str_t                  name;
    ngx_thread_pool_t         *tp;
    ngx_http_request_t        *r;
    ngx_output_chain_ctx_t    *ctx;
    ngx_http_core_loc_conf_t  *clcf;

    r = file->thread_ctx;

    clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
    tp = clcf->thread_pool;

    if (tp == NULL) {
        if (ngx_http_complex_value(r, clcf->thread_pool_value, &name)
            != NGX_OK)
        {
            return NGX_ERROR;
        }

        tp = ngx_thread_pool_get((ngx_cycle_t *) ngx_cycle, &name);

        if (tp == NULL) {
            ngx_log_error(NGX_LOG_ERR, r->connection->log, 0,
                          "thread pool \"%V\" not found", &name);
            return NGX_ERROR;
        }
    }

    task->event.data = r;
    task->event.handler = ngx_http_copy_thread_event_handler;

    if (ngx_thread_task_post(tp, task) != NGX_OK) {
        return NGX_ERROR;
    }

    r->main->blocked++;
    r->aio = 1;

    ctx = ngx_http_get_module_ctx(r, ngx_http_copy_filter_module);
    ctx->aio = 1;

    return NGX_OK;
}


static void
ngx_http_copy_thread_event_handler(ngx_event_t *ev)
{
    ngx_http_request_t  *r;

    r = ev->data;

    r->main->blocked--;
    r->aio = 0;

    r->connection->write->handler(r->connection->write);
}

#endif


static void *
ngx_http_copy_filter_create_conf(ngx_conf_t *cf)
{
    ngx_http_copy_filter_conf_t *conf;

    conf = ngx_palloc(cf->pool, sizeof(ngx_http_copy_filter_conf_t));
    if (conf == NULL) {
        return NULL;
    }

    conf->bufs.num = 0;

    return conf;
}


static char *
ngx_http_copy_filter_merge_conf(ngx_conf_t *cf, void *parent, void *child)
{
    ngx_http_copy_filter_conf_t *prev = parent;
    ngx_http_copy_filter_conf_t *conf = child;

    ngx_conf_merge_bufs_value(conf->bufs, prev->bufs, 2, 32768);

    return NULL;
}


static ngx_int_t
ngx_http_copy_filter_init(ngx_conf_t *cf)
{
    ngx_http_next_body_filter = ngx_http_top_body_filter;
    ngx_http_top_body_filter = ngx_http_copy_filter;

    return NGX_OK;
}