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Replacement for fetch() which operates asynchronously and identifies
protocols by URI scheme.
This commit is contained in:
Michael Brown
172
src/core/download.c
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172
src/core/download.c
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@@ -0,0 +1,172 @@
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/*
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* Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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/**
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* @file
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*
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* Download protocols
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*
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*/
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#include <stdint.h>
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#include <stdlib.h>
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#include <errno.h>
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#include <gpxe/umalloc.h>
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#include <gpxe/ebuffer.h>
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#include <gpxe/download.h>
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/** Registered download protocols */
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static struct download_protocol download_protocols[0]
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__table_start ( struct download_protocol, download_protocols );
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static struct download_protocol download_protocols_end[0]
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__table_end ( struct download_protocol, download_protocols );
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/**
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* Identify download protocol
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*
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* @v name Download protocol name
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* @ret protocol Download protocol, or NULL
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*/
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static struct download_protocol * find_protocol ( const char *name ) {
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struct download_protocol *protocol;
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for ( protocol = download_protocols; protocol < download_protocols_end;
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protocol++ ) {
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if ( strcmp ( name, protocol->name ) == 0 )
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return protocol;
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}
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return NULL;
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}
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/** Free download resources */
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static void download_reap ( struct async *async ) {
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struct download *download =
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container_of ( async, struct download, async );
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free ( download );
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}
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/**
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* Handle download termination
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*
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* @v async Download asynchronous operation
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* @v signal SIGCHLD
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*/
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static void download_sigchld ( struct async *async,
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enum signal signal __unused ) {
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struct download *download =
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container_of ( async, struct download, async );
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int rc;
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/* Reap child */
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async_wait ( async, &rc, 1 );
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/* Clean up */
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if ( rc == 0 ) {
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/* Transfer ownership of buffer to parent */
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*(download->data) = download->buffer.addr;
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*(download->len) = download->buffer.fill;
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} else {
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/* Discard the buffer */
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ufree ( download->buffer.addr );
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}
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free_uri ( download->uri );
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download->uri = NULL;
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/* Terminate ourselves */
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async_done ( async, rc );
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}
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/** Download asynchronous operations */
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static struct async_operations download_async_operations = {
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.reap = download_reap,
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.signal = {
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[SIGCHLD] = download_sigchld,
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},
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};
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/**
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* Start download
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*
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* @v uri_string URI as a string (e.g. "http://www.nowhere.com/vmlinuz")
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* @v parent Parent asynchronous operation
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* @ret data Loaded file
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* @ret len Length of loaded file
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* @ret rc Return status code
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*
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* Starts download of a file to a user buffer. The user buffer is
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* allocated with umalloc(). The parent asynchronous operation will
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* be notified via SIGCHLD when the download completes. If the
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* download completes successfully, the @c data and @c len fields will
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* have been filled in, and the parent takes ownership of the buffer,
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* which must eventually be freed with ufree().
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*
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* The uri_string does not need to remain persistent for the duration
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* of the download; the parent may discard it as soon as
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* start_download returns.
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*/
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int start_download ( const char *uri_string, struct async *parent,
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userptr_t *data, size_t *len ) {
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struct download *download;
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int rc;
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/* Allocate and populate download structure */
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download = malloc ( sizeof ( *download ) );
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if ( ! download )
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return -ENOMEM;
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memset ( download, 0, sizeof ( *download ) );
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download->data = data;
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download->len = len;
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async_init ( &download->async, &download_async_operations, parent );
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/* Parse the URI */
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download->uri = parse_uri ( uri_string );
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if ( ! download->uri ) {
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rc = -ENOMEM;
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goto err;
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}
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/* Allocate an expandable buffer to hold the file */
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if ( ( rc = ebuffer_alloc ( &download->buffer, 0 ) ) != 0 )
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goto err;
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/* Identify the download protocol */
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download->protocol = find_protocol ( download->uri->scheme );
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if ( ! download->protocol ) {
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DBG ( "No such protocol \"%s\"\n", download->uri->scheme );
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rc = -ENOTSUP;
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goto err;
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}
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/* Start the actual download */
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if ( ( rc = download->protocol->start_download ( download->uri,
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&download->buffer, &download->async ) ) != 0 ) {
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DBG ( "Could not start \"%s\" download: %s\n",
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download->uri->scheme, strerror ( rc ) );
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goto err;
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}
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return 0;
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err:
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async_uninit ( &download->async );
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ufree ( download->buffer.addr );
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free_uri ( download->uri );
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free ( download );
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return rc;
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}
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59
src/include/gpxe/download.h
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59
src/include/gpxe/download.h
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@@ -0,0 +1,59 @@
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#ifndef _GPXE_DOWNLOAD_H
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#define _GPXE_DOWNLOAD_H
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/** @file
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*
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* Download protocols
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*
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*/
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#include <stdint.h>
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#include <gpxe/uaccess.h>
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#include <gpxe/async.h>
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#include <gpxe/buffer.h>
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#include <gpxe/uri.h>
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#include <gpxe/tables.h>
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/** A download protocol */
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struct download_protocol {
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/** Protocol name (e.g. "http") */
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const char *name;
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/** Start a download via this protocol
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*
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* @v uri Uniform Resource Identifier
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* @v buffer Buffer into which to download file
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* @v parent Parent asynchronous operation
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* @ret rc Return status code
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*
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* The @c uri and @c buffer will remain persistent for the
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* duration of the asynchronous operation.
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*/
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int ( * start_download ) ( struct uri *uri, struct buffer *buffer,
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struct async *parent );
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};
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/** Register a download protocol */
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#define __download_protocol __table ( struct download_protocol, \
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download_protocols, 01 )
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/** A download in progress */
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struct download {
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/** User buffer allocated for the download */
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userptr_t *data;
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/** Size of the download */
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size_t *len;
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/** URI being downloaded */
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struct uri *uri;
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/** Expandable buffer for this download */
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struct buffer buffer;
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/** Download protocol */
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struct download_protocol *protocol;
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/** Asynchronous operation for this download */
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struct async async;
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};
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extern int start_download ( const char *uri_string, struct async *parent,
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userptr_t *data, size_t *len );
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#endif /* _GPXE_DOWNLOAD_H */
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