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view src/http/ngx_http_copy_filter_module.c @ 7152:3b635e8fd499

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FastCGI: adjust buffer position when parsing incomplete records. Previously, nginx failed to move buffer position when parsing an incomplete record header, and due to this wasn't be able to continue parsing once remaining bytes of the record header were received. This can affect response header parsing, potentially generating spurious errors like "upstream sent unexpected FastCGI request id high byte: 1 while reading response header from upstream". While this is very unlikely, since usually record headers are written in a single buffer, this still can happen in real life, for example, if a record header will be split across two TCP packets and the second packet will be delayed. This does not affect non-buffered response body proxying, due to "buf->pos = buf->last;" at the start of the ngx_http_fastcgi_non_buffered_filter() function. Also this does not affect buffered response body proxying, as each input buffer is only passed to the filter once.
author Maxim Dounin <mdounin@mdounin.ru>
date Thu, 09 Nov 2017 15:35:20 +0300
parents ce37362a7a70
children 555533169506
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_connection_t    *c;
    ngx_http_request_t  *r;

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

    ngx_http_set_log_request(c->log, r);

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

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

    r->write_event_handler(r);

    ngx_http_run_posted_requests(c);
}


#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_connection_t    *c;
    ngx_http_request_t  *r;

    r = ev->data;
    c = r->connection;

    ngx_http_set_log_request(c->log, r);

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

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

    if (r->done) {
        /*
         * trigger connection event handler if the subrequest was
         * already finalized; this can happen if the handler is used
         * for sendfile() in threads
         */

        c->write->handler(c->write);

    } else {
        r->write_event_handler(r);
        ngx_http_run_posted_requests(c);
    }
}

#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;
}