Mercurial > hg > nginx
view src/os/unix/ngx_linux_aio_read.c @ 7948:a2613fc1bce5
Fixed sendfile() limit handling on Linux.
On Linux starting with 2.6.16, sendfile() silently limits all operations
to MAX_RW_COUNT, defined as (INT_MAX & PAGE_MASK). This incorrectly
triggered the interrupt check, and resulted in 0-sized writev() on the
next loop iteration.
Fix is to make sure the limit is always checked, so we will return from
the loop if the limit is already reached even if number of bytes sent is
not exactly equal to the number of bytes we've tried to send.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Fri, 29 Oct 2021 20:21:51 +0300 |
parents | f01ab2dbcfdc |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> #include <ngx_event.h> extern int ngx_eventfd; extern aio_context_t ngx_aio_ctx; static void ngx_file_aio_event_handler(ngx_event_t *ev); static int io_submit(aio_context_t ctx, long n, struct iocb **paiocb) { return syscall(SYS_io_submit, ctx, n, paiocb); } ngx_int_t ngx_file_aio_init(ngx_file_t *file, ngx_pool_t *pool) { ngx_event_aio_t *aio; aio = ngx_pcalloc(pool, sizeof(ngx_event_aio_t)); if (aio == NULL) { return NGX_ERROR; } aio->file = file; aio->fd = file->fd; aio->event.data = aio; aio->event.ready = 1; aio->event.log = file->log; file->aio = aio; return NGX_OK; } ssize_t ngx_file_aio_read(ngx_file_t *file, u_char *buf, size_t size, off_t offset, ngx_pool_t *pool) { ngx_err_t err; struct iocb *piocb[1]; ngx_event_t *ev; ngx_event_aio_t *aio; if (!ngx_file_aio) { return ngx_read_file(file, buf, size, offset); } if (file->aio == NULL && ngx_file_aio_init(file, pool) != NGX_OK) { return NGX_ERROR; } aio = file->aio; ev = &aio->event; if (!ev->ready) { ngx_log_error(NGX_LOG_ALERT, file->log, 0, "second aio post for \"%V\"", &file->name); return NGX_AGAIN; } ngx_log_debug4(NGX_LOG_DEBUG_CORE, file->log, 0, "aio complete:%d @%O:%uz %V", ev->complete, offset, size, &file->name); if (ev->complete) { ev->active = 0; ev->complete = 0; if (aio->res >= 0) { ngx_set_errno(0); return aio->res; } ngx_set_errno(-aio->res); ngx_log_error(NGX_LOG_CRIT, file->log, ngx_errno, "aio read \"%s\" failed", file->name.data); return NGX_ERROR; } ngx_memzero(&aio->aiocb, sizeof(struct iocb)); aio->aiocb.aio_data = (uint64_t) (uintptr_t) ev; aio->aiocb.aio_lio_opcode = IOCB_CMD_PREAD; aio->aiocb.aio_fildes = file->fd; aio->aiocb.aio_buf = (uint64_t) (uintptr_t) buf; aio->aiocb.aio_nbytes = size; aio->aiocb.aio_offset = offset; aio->aiocb.aio_flags = IOCB_FLAG_RESFD; aio->aiocb.aio_resfd = ngx_eventfd; ev->handler = ngx_file_aio_event_handler; piocb[0] = &aio->aiocb; if (io_submit(ngx_aio_ctx, 1, piocb) == 1) { ev->active = 1; ev->ready = 0; ev->complete = 0; return NGX_AGAIN; } err = ngx_errno; if (err == NGX_EAGAIN) { return ngx_read_file(file, buf, size, offset); } ngx_log_error(NGX_LOG_CRIT, file->log, err, "io_submit(\"%V\") failed", &file->name); if (err == NGX_ENOSYS) { ngx_file_aio = 0; return ngx_read_file(file, buf, size, offset); } return NGX_ERROR; } static void ngx_file_aio_event_handler(ngx_event_t *ev) { ngx_event_aio_t *aio; aio = ev->data; ngx_log_debug2(NGX_LOG_DEBUG_CORE, ev->log, 0, "aio event handler fd:%d %V", aio->fd, &aio->file->name); aio->handler(ev); }