Mercurial > hg > nginx
view src/http/ngx_http_copy_filter_module.c @ 8018:5119c8150478
Fixed runtime handling of systems without EPOLLRDHUP support.
In 7583:efd71d49bde0 (nginx 1.17.5) along with introduction of the
ioctl(FIONREAD) support proper handling of systems without EPOLLRDHUP
support in the kernel (but with EPOLLRDHUP in headers) was broken.
Before the change, rev->available was never set to 0 unless
ngx_use_epoll_rdhup was also set (that is, runtime test for EPOLLRDHUP
introduced in 6536:f7849bfb6d21 succeeded). After the change,
rev->available might reach 0 on systems without runtime EPOLLRDHUP
support, stopping further reading in ngx_readv_chain() and ngx_unix_recv().
And, if EOF happened to be already reported along with the last event,
it is not reported again by epoll_wait(), leading to connection hangs
and timeouts on such systems.
This affects Linux kernels before 2.6.17 if nginx was compiled
with newer headers, and, more importantly, emulation layers, such as
DigitalOcean's App Platform's / gVisor's epoll emulation layer.
Fix is to explicitly check ngx_use_epoll_rdhup before the corresponding
rev->pending_eof tests in ngx_readv_chain() and ngx_unix_recv().
author | Marcus Ball <marcus.ball@live.com> |
---|---|
date | Mon, 30 May 2022 02:38:07 +0300 |
parents | ec2e6893caaa |
children | e88cdaa0f1ff |
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/* * 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); #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; } #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); } #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_connection_t *c; 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; if (r->aio) { /* * tolerate sendfile() calls if another operation is already * running; this can happen due to subrequests, multiple calls * of the next body filter from a filter, or in HTTP/2 due to * a write event on the main connection */ c = r->connection; #if (NGX_HTTP_V2) if (r->stream) { c = r->stream->connection->connection; } #endif if (task == c->sendfile_task) { return NGX_OK; } } 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 (NGX_HTTP_V2) if (r->stream) { /* * for HTTP/2, update write event to make sure processing will * reach the main connection to handle sendfile() in threads */ c->write->ready = 1; c->write->active = 0; } #endif 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; }