/*
* 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.
*/
FILE_LICENCE ( GPL2_OR_LATER );
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <ipxe/list.h>
#include <ipxe/xfer.h>
#include <ipxe/open.h>
#include <ipxe/process.h>
#include <ipxe/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 iPXE 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 );
/**
* 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 ) {
list_del ( &iobuf->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 deliver_iob() event
*
* @v xfer POSIX file data transfer interface
* @v iobuf I/O buffer
* @v meta Data transfer metadata
* @ret rc Return status code
*/
static int
posix_file_xfer_deliver_iob ( struct xfer_interface *xfer,
struct io_buffer *iobuf,
struct xfer_metadata *meta ) {
struct posix_file *file =
container_of ( xfer, struct posix_file, xfer );
/* Keep track of file position solely for the filesize */
if ( meta->whence != SEEK_CUR )
file->pos = 0;
file->pos += meta->offset;
if ( file->filesize < file->pos )
file->filesize = file->pos;
if ( iob_len ( iobuf ) ) {
list_add_tail ( &iobuf->list, &file->data );
} else {
free_iob ( iobuf );
}
return 0;
}
/** POSIX file data transfer interface operations */
static struct xfer_interface_operations posix_file_xfer_operations = {
.close = posix_file_xfer_close,
.vredirect = xfer_vreopen,
.window = unlimited_xfer_window,
.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;
}
DBG ( "POSIX could not find free file descriptor\n" );
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 = zalloc ( sizeof ( *file ) );
if ( ! file )
return -ENOMEM;
ref_init ( &file->refcnt, 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_string ( &file->xfer, uri_string ) ) != 0 )
goto err;
/* Wait for open to succeed or fail */
while ( list_empty ( &file->data ) ) {
step();
if ( file->rc == 0 )
break;
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 );
DBG ( "POSIX opened %s as file %d\n", uri_string, fd );
return fd;
err:
posix_file_finished ( file, rc );
ref_put ( &file->refcnt );
return rc;
}
/**
* Check file descriptors for readiness
*
* @v readfds File descriptors to check
* @v wait Wait until data is ready
* @ret nready Number of ready file descriptors
*/
int select ( fd_set *readfds, int wait ) {
struct posix_file *file;
int fd;
do {
for ( fd = POSIX_FD_MIN ; fd <= POSIX_FD_MAX ; fd++ ) {
if ( ! FD_ISSET ( fd, readfds ) )
continue;
file = posix_fd_to_file ( fd );
if ( ! file )
return -EBADF;
if ( ( list_empty ( &file->data ) ) &&
( file->rc == -EINPROGRESS ) )
continue;
/* Data is available or status has changed */
FD_ZERO ( readfds );
FD_SET ( fd, readfds );
return 1;
}
step();
} while ( wait );
return 0;
}
/**
* 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
*
* This call is non-blocking; if no data is available to read then
* -EWOULDBLOCK will be returned.
*/
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 len;
/* Identify file */
file = posix_fd_to_file ( fd );
if ( ! file )
return -EBADF;
/* 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 ) {
len = iob_len ( iobuf );
if ( len > max_len )
len = max_len;
copy_to_user ( buffer, offset, iobuf->data, len );
iob_pull ( iobuf, len );
if ( ! iob_len ( iobuf ) ) {
list_del ( &iobuf->list );
free_iob ( iobuf );
}
file->pos += len;
assert ( len != 0 );
return len;
}
/* If file has completed, return (after returning all data) */
if ( file->rc != -EINPROGRESS ) {
assert ( list_empty ( &file->data ) );
return file->rc;
}
/* No data ready and file still in progress; return -WOULDBLOCK */
return -EWOULDBLOCK;
}
/**
* 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;
}
