view src/http/modules/ngx_http_stub_status_module.c @ 6876:a5d1b1383dea tip

Upstream: fixed cache corruption and socket leaks with aio_write. The ngx_event_pipe() function wasn't called on write events with wev->delayed set. As a result, threaded writing results weren't properly collected in ngx_event_pipe_write_to_downstream() when a write event was triggered for a completed write. Further, this wasn't detected, as p->aio was reset by a thread completion handler, and results were later collected in ngx_event_pipe_read_upstream() instead of scheduling a new write of additional data. If this happened on the last reading from an upstream, last part of the response was never written to the cache file. Similar problems might also happen in case of timeouts when writing to client, as this also results in ngx_event_pipe() not being called on write events. In this scenario socket leaks were observed. Fix is to check if p->writing is set in ngx_event_pipe_read_upstream(), and therefore collect results of previous write operations in case of read events as well, similar to how we do so in ngx_event_pipe_write_downstream(). This is enough to fix the wev->delayed case. Additionally, we now call ngx_event_pipe() from ngx_http_upstream_process_request() if there are uncollected write operations (p->writing and !p->aio). This also fixes the wev->timedout case.
author Maxim Dounin <mdounin@mdounin.ru>
date Fri, 20 Jan 2017 21:14:19 +0300
parents b1858fc47e3b
children
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>


static ngx_int_t ngx_http_stub_status_handler(ngx_http_request_t *r);
static ngx_int_t ngx_http_stub_status_variable(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data);
static ngx_int_t ngx_http_stub_status_add_variables(ngx_conf_t *cf);
static char *ngx_http_set_stub_status(ngx_conf_t *cf, ngx_command_t *cmd,
    void *conf);


static ngx_command_t  ngx_http_status_commands[] = {

    { ngx_string("stub_status"),
      NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_NOARGS|NGX_CONF_TAKE1,
      ngx_http_set_stub_status,
      0,
      0,
      NULL },

      ngx_null_command
};


static ngx_http_module_t  ngx_http_stub_status_module_ctx = {
    ngx_http_stub_status_add_variables,    /* preconfiguration */
    NULL,                                  /* postconfiguration */

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

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

    NULL,                                  /* create location configuration */
    NULL                                   /* merge location configuration */
};


ngx_module_t  ngx_http_stub_status_module = {
    NGX_MODULE_V1,
    &ngx_http_stub_status_module_ctx,      /* module context */
    ngx_http_status_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_variable_t  ngx_http_stub_status_vars[] = {

    { ngx_string("connections_active"), NULL, ngx_http_stub_status_variable,
      0, NGX_HTTP_VAR_NOCACHEABLE, 0 },

    { ngx_string("connections_reading"), NULL, ngx_http_stub_status_variable,
      1, NGX_HTTP_VAR_NOCACHEABLE, 0 },

    { ngx_string("connections_writing"), NULL, ngx_http_stub_status_variable,
      2, NGX_HTTP_VAR_NOCACHEABLE, 0 },

    { ngx_string("connections_waiting"), NULL, ngx_http_stub_status_variable,
      3, NGX_HTTP_VAR_NOCACHEABLE, 0 },

    { ngx_null_string, NULL, NULL, 0, 0, 0 }
};


static ngx_int_t
ngx_http_stub_status_handler(ngx_http_request_t *r)
{
    size_t             size;
    ngx_int_t          rc;
    ngx_buf_t         *b;
    ngx_chain_t        out;
    ngx_atomic_int_t   ap, hn, ac, rq, rd, wr, wa;

    if (!(r->method & (NGX_HTTP_GET|NGX_HTTP_HEAD))) {
        return NGX_HTTP_NOT_ALLOWED;
    }

    rc = ngx_http_discard_request_body(r);

    if (rc != NGX_OK) {
        return rc;
    }

    r->headers_out.content_type_len = sizeof("text/plain") - 1;
    ngx_str_set(&r->headers_out.content_type, "text/plain");
    r->headers_out.content_type_lowcase = NULL;

    if (r->method == NGX_HTTP_HEAD) {
        r->headers_out.status = NGX_HTTP_OK;

        rc = ngx_http_send_header(r);

        if (rc == NGX_ERROR || rc > NGX_OK || r->header_only) {
            return rc;
        }
    }

    size = sizeof("Active connections:  \n") + NGX_ATOMIC_T_LEN
           + sizeof("server accepts handled requests\n") - 1
           + 6 + 3 * NGX_ATOMIC_T_LEN
           + sizeof("Reading:  Writing:  Waiting:  \n") + 3 * NGX_ATOMIC_T_LEN;

    b = ngx_create_temp_buf(r->pool, size);
    if (b == NULL) {
        return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }

    out.buf = b;
    out.next = NULL;

    ap = *ngx_stat_accepted;
    hn = *ngx_stat_handled;
    ac = *ngx_stat_active;
    rq = *ngx_stat_requests;
    rd = *ngx_stat_reading;
    wr = *ngx_stat_writing;
    wa = *ngx_stat_waiting;

    b->last = ngx_sprintf(b->last, "Active connections: %uA \n", ac);

    b->last = ngx_cpymem(b->last, "server accepts handled requests\n",
                         sizeof("server accepts handled requests\n") - 1);

    b->last = ngx_sprintf(b->last, " %uA %uA %uA \n", ap, hn, rq);

    b->last = ngx_sprintf(b->last, "Reading: %uA Writing: %uA Waiting: %uA \n",
                          rd, wr, wa);

    r->headers_out.status = NGX_HTTP_OK;
    r->headers_out.content_length_n = b->last - b->pos;

    b->last_buf = (r == r->main) ? 1 : 0;
    b->last_in_chain = 1;

    rc = ngx_http_send_header(r);

    if (rc == NGX_ERROR || rc > NGX_OK || r->header_only) {
        return rc;
    }

    return ngx_http_output_filter(r, &out);
}


static ngx_int_t
ngx_http_stub_status_variable(ngx_http_request_t *r,
    ngx_http_variable_value_t *v, uintptr_t data)
{
    u_char            *p;
    ngx_atomic_int_t   value;

    p = ngx_pnalloc(r->pool, NGX_ATOMIC_T_LEN);
    if (p == NULL) {
        return NGX_ERROR;
    }

    switch (data) {
    case 0:
        value = *ngx_stat_active;
        break;

    case 1:
        value = *ngx_stat_reading;
        break;

    case 2:
        value = *ngx_stat_writing;
        break;

    case 3:
        value = *ngx_stat_waiting;
        break;

    /* suppress warning */
    default:
        value = 0;
        break;
    }

    v->len = ngx_sprintf(p, "%uA", value) - p;
    v->valid = 1;
    v->no_cacheable = 0;
    v->not_found = 0;
    v->data = p;

    return NGX_OK;
}


static ngx_int_t
ngx_http_stub_status_add_variables(ngx_conf_t *cf)
{
    ngx_http_variable_t  *var, *v;

    for (v = ngx_http_stub_status_vars; v->name.len; v++) {
        var = ngx_http_add_variable(cf, &v->name, v->flags);
        if (var == NULL) {
            return NGX_ERROR;
        }

        var->get_handler = v->get_handler;
        var->data = v->data;
    }

    return NGX_OK;
}


static char *
ngx_http_set_stub_status(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_http_core_loc_conf_t  *clcf;

    clcf = ngx_http_conf_get_module_loc_conf(cf, ngx_http_core_module);
    clcf->handler = ngx_http_stub_status_handler;

    return NGX_CONF_OK;
}