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view src/misc/ngx_google_perftools_module.c @ 6806:75dbab4ea930

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Events: improved error event handling for UDP sockets. Normally, the epoll module calls the read and write handlers depending on whether EPOLLIN and EPOLLOUT are reported by epoll_wait(). No error processing is done in the module, the handlers are expected to get an error when doing I/O. If an error event is reported without EPOLLIN and EPOLLOUT, the module set both EPOLLIN and EPOLLOUT to ensure the error event is handled at least in one active handler. This works well unless the error is delivered along with only one of EPOLLIN or EPOLLOUT, and the corresponding handler does not do any I/O. For example, it happened when getting EPOLLERR|EPOLLOUT from epoll_wait() upon receiving "ICMP port unreachable" while proxying UDP. As the write handler had nothing to send it was not able to detect and log an error, and did not switch to the next upstream. The fix is to unconditionally set EPOLLIN and EPOLLOUT in case of an error event. In the aforementioned case, this causes the read handler to be called which does recv() and detects an error. In addition to the epoll module, analogous changes were made in devpoll/eventport/poll.
author Dmitry Volyntsev <xeioex@nginx.com>
date Mon, 21 Nov 2016 16:03:42 +0300
parents d620f497c50f
children a27e0c7e198c
line wrap: on
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/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


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

/*
 * declare Profiler interface here because
 * <google/profiler.h> is C++ header file
 */

int ProfilerStart(u_char* fname);
void ProfilerStop(void);
void ProfilerRegisterThread(void);


static void *ngx_google_perftools_create_conf(ngx_cycle_t *cycle);
static ngx_int_t ngx_google_perftools_worker(ngx_cycle_t *cycle);


typedef struct {
    ngx_str_t  profiles;
} ngx_google_perftools_conf_t;


static ngx_command_t  ngx_google_perftools_commands[] = {

    { ngx_string("google_perftools_profiles"),
      NGX_MAIN_CONF|NGX_DIRECT_CONF|NGX_CONF_TAKE1,
      ngx_conf_set_str_slot,
      0,
      offsetof(ngx_google_perftools_conf_t, profiles),
      NULL },

    ngx_null_command
};


static ngx_core_module_t  ngx_google_perftools_module_ctx = {
    ngx_string("google_perftools"),
    ngx_google_perftools_create_conf,
    NULL
};


ngx_module_t  ngx_google_perftools_module = {
    NGX_MODULE_V1,
    &ngx_google_perftools_module_ctx,      /* module context */
    ngx_google_perftools_commands,         /* module directives */
    NGX_CORE_MODULE,                       /* module type */
    NULL,                                  /* init master */
    NULL,                                  /* init module */
    ngx_google_perftools_worker,           /* init process */
    NULL,                                  /* init thread */
    NULL,                                  /* exit thread */
    NULL,                                  /* exit process */
    NULL,                                  /* exit master */
    NGX_MODULE_V1_PADDING
};


static void *
ngx_google_perftools_create_conf(ngx_cycle_t *cycle)
{
    ngx_google_perftools_conf_t  *gptcf;

    gptcf = ngx_pcalloc(cycle->pool, sizeof(ngx_google_perftools_conf_t));
    if (gptcf == NULL) {
        return NULL;
    }

    /*
     * set by ngx_pcalloc()
     *
     *     gptcf->profiles = { 0, NULL };
     */

    return gptcf;
}


static ngx_int_t
ngx_google_perftools_worker(ngx_cycle_t *cycle)
{
    u_char                       *profile;
    ngx_google_perftools_conf_t  *gptcf;

    gptcf = (ngx_google_perftools_conf_t *)
                ngx_get_conf(cycle->conf_ctx, ngx_google_perftools_module);

    if (gptcf->profiles.len == 0) {
        return NGX_OK;
    }

    profile = ngx_alloc(gptcf->profiles.len + NGX_INT_T_LEN + 2, cycle->log);
    if (profile == NULL) {
        return NGX_OK;
    }

    if (getenv("CPUPROFILE")) {
        /* disable inherited Profiler enabled in master process */
        ProfilerStop();
    }

    ngx_sprintf(profile, "%V.%d%Z", &gptcf->profiles, ngx_pid);

    if (ProfilerStart(profile)) {
        /* start ITIMER_PROF timer */
        ProfilerRegisterThread();

    } else {
        ngx_log_error(NGX_LOG_CRIT, cycle->log, ngx_errno,
                      "ProfilerStart(%s) failed", profile);
    }

    ngx_free(profile);

    return NGX_OK;
}


/* ProfilerStop() is called on Profiler destruction */