Mercurial > hg > nginx
view src/os/unix/ngx_linux_aio_read.c @ 7784:8cc5b0365ee5
Improved maximum errno detection.
Previously, systems without sys_nerr (or _sys_nerr) were handled with an
assumption that errors start at 0 and continuous. This is, however, not
something POSIX requires, and not true on some platforms.
Notably, on Linux, where sys_nerr is no longer available for newly linked
binaries starting with glibc 2.32, there are gaps in error list, which
used to stop us from properly detecting maximum errno. Further, on
GNU/Hurd errors start at 0x40000001.
With this change, maximum errno detection is moved to the runtime code,
now able to ignore gaps, and also detects the first error if needed.
This fixes observed "Unknown error" messages as seen on Linux with
glibc 2.32 and on GNU/Hurd.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Mon, 01 Mar 2021 20:00:43 +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); }