view src/http/modules/ngx_http_stub_status_module.c @ 7151:9ef704d8563a tip

Core: free shared memory zones only after reconfiguration. This is what usually happens for zones no longer used in the new configuration, but zones where size or tag were changed were freed when creating new memory zones. If reconfiguration failed (for example, due to a conflicting listening socket), this resulted in a segmentation fault in the master process. Reported by Zhihua Cao, http://mailman.nginx.org/pipermail/nginx-devel/2017-October/010536.html.
author Maxim Dounin <mdounin@mdounin.ru>
date Tue, 17 Oct 2017 19:52:16 +0300
parents 2a288909abc6
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_http_null_variable
};


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;
}