/*
* Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of the
* License, or any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <gpxe/list.h>
#include <gpxe/xfer.h>
#include <gpxe/open.h>
#include <gpxe/process.h>
#include <gpxe/posix_io.h>
/** @file
*
* POSIX-like I/O
*
* These functions provide traditional blocking I/O semantics. They
* are designed to be used by the PXE TFTP API. Because they block,
* they may not be used by most other portions of the gPXE codebase.
*/
/** An open file */
struct posix_file {
/** Reference count for this object */
struct refcnt refcnt;
/** List of open files */
struct list_head list;
/** File descriptor */
int fd;
/** Overall status
*
* Set to -EINPROGRESS while data transfer is in progress.
*/
int rc;
/** Data transfer interface */
struct xfer_interface xfer;
/** Current seek position */
size_t pos;
/** File size */
size_t filesize;
/** Received data queue */
struct list_head data;
};
/** List of open files */
static LIST_HEAD ( posix_files );
/** Minimum file descriptor that will ever be allocated */
#define POSIX_FD_MIN ( 1 )
/** Maximum file descriptor that will ever be allocated */
#define POSIX_FD_MAX ( 255 )
/**
* Free open file
*
* @v refcnt Reference counter
*/
static void posix_file_free ( struct refcnt *refcnt ) {
struct posix_file *file =
container_of ( refcnt, struct posix_file, refcnt );
struct io_buffer *iobuf;
struct io_buffer *tmp;
list_for_each_entry_safe ( iobuf, tmp, &file->data, list ) {
free_iob ( iobuf );
}
free ( file );
}
/**
* Terminate file data transfer
*
* @v file POSIX file
* @v rc Reason for termination
*/
static void posix_file_finished ( struct posix_file *file, int rc ) {
xfer_nullify ( &file->xfer );
xfer_close ( &file->xfer, rc );
file->rc = rc;
}
/**
* Handle close() event
*
* @v xfer POSIX file data transfer interface
* @v rc Reason for close
*/
static void posix_file_xfer_close ( struct xfer_interface *xfer, int rc ) {
struct posix_file *file =
container_of ( xfer, struct posix_file, xfer );
posix_file_finished ( file, rc );
}
/**
* Handle seek() event
*
* @v xfer POSIX file data transfer interface
* @v pos New position
* @ret rc Return status code
*/
static int posix_file_xfer_seek ( struct xfer_interface *xfer, off_t offset,
int whence ) {
struct posix_file *file =
container_of ( xfer, struct posix_file, xfer );
switch ( whence ) {
case SEEK_SET:
file->pos = offset;
break;
case SEEK_CUR:
file->pos += offset;
break;
}
if ( file->filesize < file->pos )
file->filesize = file->pos;
return 0;
}
/**
* Handle deliver_iob() event
*
* @v xfer POSIX file data transfer interface
* @v iobuf I/O buffer
* @ret rc Return status code
*/
static int posix_file_xfer_deliver_iob ( struct xfer_interface *xfer,
struct io_buffer *iobuf ) {
struct posix_file *file =
container_of ( xfer, struct posix_file, xfer );
list_add_tail ( &iobuf->list, &file->data );
return 0;
}
/** POSIX file data transfer interface operations */
static struct xfer_interface_operations posix_file_xfer_operations = {
.close = posix_file_xfer_close,
.vredirect = xfer_vopen,
.request = ignore_xfer_request,
.seek = posix_file_xfer_seek,
.alloc_iob = default_xfer_alloc_iob,
.deliver_iob = posix_file_xfer_deliver_iob,
.deliver_raw = xfer_deliver_as_iob,
};
/**
* Identify file by file descriptor
*
* @v fd File descriptor
* @ret file Corresponding file, or NULL
*/
static struct posix_file * posix_fd_to_file ( int fd ) {
struct posix_file *file;
list_for_each_entry ( file, &posix_files, list ) {
if ( file->fd == fd )
return file;
}
return NULL;
}
/**
* Find an available file descriptor
*
* @ret fd File descriptor, or negative error number
*/
static int posix_find_free_fd ( void ) {
int fd;
for ( fd = POSIX_FD_MIN ; fd <= POSIX_FD_MAX ; fd++ ) {
if ( ! posix_fd_to_file ( fd ) )
return fd;
}
return -ENFILE;
}
/**
* Open file
*
* @v uri_string URI string
* @ret fd File descriptor, or negative error number
*/
int open ( const char *uri_string ) {
struct posix_file *file;
int fd;
int rc;
/* Find a free file descriptor to use */
fd = posix_find_free_fd();
if ( fd < 0 )
return fd;
/* Allocate and initialise structure */
file = malloc ( sizeof ( *file ) );
if ( ! file )
return -ENOMEM;
memset ( file, 0, sizeof ( *file ) );
file->refcnt.free = posix_file_free;
file->fd = fd;
file->rc = -EINPROGRESS;
xfer_init ( &file->xfer, &posix_file_xfer_operations,
&file->refcnt );
INIT_LIST_HEAD ( &file->data );
/* Open URI on data transfer interface */
if ( ( rc = xfer_open_uri ( &file->xfer, uri_string ) ) != 0 )
goto err;
/* Request data */
if ( ( rc = xfer_request_all ( &file->xfer ) ) != 0 )
goto err;
/* Wait for open to succeed or fail */
while ( list_empty ( &file->data ) ) {
step();
if ( file->rc != -EINPROGRESS ) {
rc = file->rc;
goto err;
}
}
/* Add to list of open files. List takes reference ownership. */
list_add ( &file->list, &posix_files );
return fd;
err:
posix_file_finished ( file, rc );
ref_put ( &file->refcnt );
return rc;
}
/**
* Read data from file
*
* @v buffer Data buffer
* @v offset Starting offset within data buffer
* @v len Maximum length to read
* @ret len Actual length read, or negative error number
*/
ssize_t read_user ( int fd, userptr_t buffer, off_t offset, size_t max_len ) {
struct posix_file *file;
struct io_buffer *iobuf;
size_t frag_len;
ssize_t len = 0;
/* Identify file */
file = posix_fd_to_file ( fd );
if ( ! file )
return -EBADF;
while ( 1 ) {
/* Try to fetch more data if none available */
if ( list_empty ( &file->data ) )
step();
/* Dequeue at most one received I/O buffer into user buffer */
list_for_each_entry ( iobuf, &file->data, list ) {
frag_len = iob_len ( iobuf );
if ( frag_len > max_len )
frag_len = max_len;
copy_to_user ( buffer, offset, iobuf->data,
frag_len );
iob_pull ( iobuf, frag_len );
if ( ! iob_len ( iobuf ) )
free_iob ( iobuf );
file->pos += frag_len;
len += frag_len;
offset += frag_len;
max_len -= frag_len;
break;
}
/* If buffer is full, return */
if ( ! max_len )
return len;
/* If file has completed, return */
if ( file->rc != -EINPROGRESS )
return ( file->rc ? file->rc : len );
}
}
/**
* Determine file size
*
* @v fd File descriptor
* @ret size File size, or negative error number
*/
ssize_t fsize ( int fd ) {
struct posix_file *file;
/* Identify file */
file = posix_fd_to_file ( fd );
if ( ! file )
return -EBADF;
return file->filesize;
}
/**
* Close file
*
* @v fd File descriptor
* @ret rc Return status code
*/
int close ( int fd ) {
struct posix_file *file;
/* Identify file */
file = posix_fd_to_file ( fd );
if ( ! file )
return -EBADF;
/* Terminate data transfer */
posix_file_finished ( file, 0 );
/* Remove from list of open files and drop reference */
list_del ( &file->list );
ref_put ( &file->refcnt );
return 0;
}
