--- /dev/null
+/*
+ * 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., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <ipxe/list.h>
+#include <ipxe/iobuf.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 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 ) {
+ intf_shutdown ( &file->xfer, rc );
+ file->rc = rc;
+}
+
+/**
+ * Handle deliver_iob() event
+ *
+ * @v file POSIX file
+ * @v iobuf I/O buffer
+ * @v meta Data transfer metadata
+ * @ret rc Return status code
+ */
+static int posix_file_xfer_deliver ( struct posix_file *file,
+ struct io_buffer *iobuf,
+ struct xfer_metadata *meta ) {
+
+ /* Keep track of file position solely for the filesize */
+ if ( meta->flags & XFER_FL_ABS_OFFSET )
+ 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 interface_operation posix_file_xfer_operations[] = {
+ INTF_OP ( xfer_deliver, struct posix_file *, posix_file_xfer_deliver ),
+ INTF_OP ( intf_close, struct posix_file *, posix_file_finished ),
+};
+
+/** POSIX file data transfer interface descriptor */
+static struct interface_descriptor posix_file_xfer_desc =
+ INTF_DESC ( struct posix_file, xfer, posix_file_xfer_operations );
+
+/**
+ * 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;
+ intf_init ( &file->xfer, &posix_file_xfer_desc, &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;
+}
Code Review / kvmfornfv.git / blobdiff