/** @file
 *
 * PXE FILE API
 *
 */

#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <byteswap.h>
#include <gpxe/uaccess.h>
#include <gpxe/posix_io.h>
#include <gpxe/features.h>
#include <pxe.h>
#include <realmode.h>

/*
 * Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
 * Portions (C) 2010 Shao Miller <shao.miller@yrdsb.edu.on.ca>.
 *              [PXE exit hook logic]
 *
 * 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 );

FEATURE ( FEATURE_MISC, "PXEXT", DHCP_EB_FEATURE_PXE_EXT, 2 );

/**
 * FILE OPEN
 *
 * @v file_open				Pointer to a struct s_PXENV_FILE_OPEN
 * @v s_PXENV_FILE_OPEN::FileName	URL of file to open
 * @ret #PXENV_EXIT_SUCCESS		File was opened
 * @ret #PXENV_EXIT_FAILURE		File was not opened
 * @ret s_PXENV_FILE_OPEN::Status	PXE status code
 * @ret s_PXENV_FILE_OPEN::FileHandle	Handle of opened file
 *
 */
PXENV_EXIT_t pxenv_file_open ( struct s_PXENV_FILE_OPEN *file_open ) {
	userptr_t filename;
	size_t filename_len;
	int fd;

	DBG ( "PXENV_FILE_OPEN" );

	/* Copy name from external program, and open it */
	filename = real_to_user ( file_open->FileName.segment,
			      file_open->FileName.offset );
	filename_len = strlen_user ( filename, 0 );
	{
		char uri_string[ filename_len + 1 ];

		copy_from_user ( uri_string, filename, 0,
				 sizeof ( uri_string ) );
		DBG ( " %s", uri_string );
		fd = open ( uri_string );
	}

	if ( fd < 0 ) {
		file_open->Status = PXENV_STATUS ( fd );
		return PXENV_EXIT_FAILURE;
	}

	DBG ( " as file %d", fd );

	file_open->FileHandle = fd;
	file_open->Status = PXENV_STATUS_SUCCESS;
	return PXENV_EXIT_SUCCESS;
}

/**
 * FILE CLOSE
 *
 * @v file_close			Pointer to a struct s_PXENV_FILE_CLOSE
 * @v s_PXENV_FILE_CLOSE::FileHandle	File handle
 * @ret #PXENV_EXIT_SUCCESS		File was closed
 * @ret #PXENV_EXIT_FAILURE		File was not closed
 * @ret s_PXENV_FILE_CLOSE::Status	PXE status code
 *
 */
PXENV_EXIT_t pxenv_file_close ( struct s_PXENV_FILE_CLOSE *file_close ) {

	DBG ( "PXENV_FILE_CLOSE %d", file_close->FileHandle );

	close ( file_close->FileHandle );
	file_close->Status = PXENV_STATUS_SUCCESS;
	return PXENV_EXIT_SUCCESS;
}

/**
 * FILE SELECT
 *
 * @v file_select			Pointer to a struct s_PXENV_FILE_SELECT
 * @v s_PXENV_FILE_SELECT::FileHandle	File handle
 * @ret #PXENV_EXIT_SUCCESS		File has been checked for readiness
 * @ret #PXENV_EXIT_FAILURE		File has not been checked for readiness
 * @ret s_PXENV_FILE_SELECT::Status	PXE status code
 * @ret s_PXENV_FILE_SELECT::Ready	Indication of readiness
 *
 */
PXENV_EXIT_t pxenv_file_select ( struct s_PXENV_FILE_SELECT *file_select ) {
	fd_set fdset;
	int ready;

	DBG ( "PXENV_FILE_SELECT %d", file_select->FileHandle );

	FD_ZERO ( &fdset );
	FD_SET ( file_select->FileHandle, &fdset );
	if ( ( ready = select ( &fdset, 0 ) ) < 0 ) {
		file_select->Status = PXENV_STATUS ( ready );
		return PXENV_EXIT_FAILURE;
	}

	file_select->Ready = ( ready ? RDY_READ : 0 );
	file_select->Status = PXENV_STATUS_SUCCESS;
	return PXENV_EXIT_SUCCESS;
}

/**
 * FILE READ
 *
 * @v file_read				Pointer to a struct s_PXENV_FILE_READ
 * @v s_PXENV_FILE_READ::FileHandle	File handle
 * @v s_PXENV_FILE_READ::BufferSize	Size of data buffer
 * @v s_PXENV_FILE_READ::Buffer		Data buffer
 * @ret #PXENV_EXIT_SUCCESS		Data has been read from file
 * @ret #PXENV_EXIT_FAILURE		Data has not been read from file
 * @ret s_PXENV_FILE_READ::Status	PXE status code
 * @ret s_PXENV_FILE_READ::Ready	Indication of readiness
 * @ret s_PXENV_FILE_READ::BufferSize	Length of data read
 *
 */
PXENV_EXIT_t pxenv_file_read ( struct s_PXENV_FILE_READ *file_read ) {
	userptr_t buffer;
	ssize_t len;

	DBG ( "PXENV_FILE_READ %d to %04x:%04x+%04x", file_read->FileHandle,
	      file_read->Buffer.segment, file_read->Buffer.offset,
	      file_read->BufferSize );

	buffer = real_to_user ( file_read->Buffer.segment,
				file_read->Buffer.offset );
	if ( ( len = read_user ( file_read->FileHandle, buffer, 0,
				file_read->BufferSize ) ) < 0 ) {
		file_read->Status = PXENV_STATUS ( len );
		return PXENV_EXIT_FAILURE;
	}

	DBG ( " read %04zx", ( ( size_t ) len ) );

	file_read->BufferSize = len;
	file_read->Status = PXENV_STATUS_SUCCESS;
	return PXENV_EXIT_SUCCESS;
}

/**
 * GET FILE SIZE
 *
 * @v get_file_size			Pointer to a struct s_PXENV_GET_FILE_SIZE
 * @v s_PXENV_GET_FILE_SIZE::FileHandle	File handle
 * @ret #PXENV_EXIT_SUCCESS		File size has been determined
 * @ret #PXENV_EXIT_FAILURE		File size has not been determined
 * @ret s_PXENV_GET_FILE_SIZE::Status	PXE status code
 * @ret s_PXENV_GET_FILE_SIZE::FileSize	Size of file
 */
PXENV_EXIT_t pxenv_get_file_size ( struct s_PXENV_GET_FILE_SIZE
				   *get_file_size ) {
	ssize_t filesize;

	DBG ( "PXENV_GET_FILE_SIZE %d", get_file_size->FileHandle );

	filesize = fsize ( get_file_size->FileHandle );
	if ( filesize < 0 ) {
		get_file_size->Status = PXENV_STATUS ( filesize );
		return PXENV_EXIT_FAILURE;
	}

	DBG ( " is %zd", ( ( size_t ) filesize ) );

	get_file_size->FileSize = filesize;
	get_file_size->Status = PXENV_STATUS_SUCCESS;
	return PXENV_EXIT_SUCCESS;
}

/**
 * FILE EXEC
 *
 * @v file_exec				Pointer to a struct s_PXENV_FILE_EXEC
 * @v s_PXENV_FILE_EXEC::Command	Command to execute
 * @ret #PXENV_EXIT_SUCCESS		Command was executed successfully
 * @ret #PXENV_EXIT_FAILURE		Command was not executed successfully
 * @ret s_PXENV_FILE_EXEC::Status	PXE status code
 *
 */
PXENV_EXIT_t pxenv_file_exec ( struct s_PXENV_FILE_EXEC *file_exec ) {
	userptr_t command;
	size_t command_len;
	int rc;

	DBG ( "PXENV_FILE_EXEC" );

	/* Copy name from external program, and exec it */
	command = real_to_user ( file_exec->Command.segment,
				 file_exec->Command.offset );
	command_len = strlen_user ( command, 0 );
	{
		char command_string[ command_len + 1 ];

		copy_from_user ( command_string, command, 0,
				 sizeof ( command_string ) );
		DBG ( " %s", command_string );

		if ( ( rc = system ( command_string ) ) != 0 ) {
			file_exec->Status = PXENV_STATUS ( rc );
			return PXENV_EXIT_FAILURE;
		}
	}

	file_exec->Status = PXENV_STATUS_SUCCESS;
	return PXENV_EXIT_SUCCESS;
}

segoff_t __data16 ( pxe_exit_hook ) = { 0, 0 };
#define pxe_exit_hook __use_data16 ( pxe_exit_hook )

/**
 * FILE API CHECK
 *
 * @v file_exec				Pointer to a struct s_PXENV_FILE_API_CHECK
 * @v s_PXENV_FILE_API_CHECK::Magic     Inbound magic number (0x91d447b2)
 * @ret #PXENV_EXIT_SUCCESS		Command was executed successfully
 * @ret #PXENV_EXIT_FAILURE		Command was not executed successfully
 * @ret s_PXENV_FILE_API_CHECK::Status	PXE status code
 * @ret s_PXENV_FILE_API_CHECK::Magic	Outbound magic number (0xe9c17b20)
 * @ret s_PXENV_FILE_API_CHECK::Provider "gPXE" (0x45585067)
 * @ret s_PXENV_FILE_API_CHECK::APIMask API function bitmask
 * @ret s_PXENV_FILE_API_CHECK::Flags	Reserved
 *
 */
PXENV_EXIT_t pxenv_file_api_check ( struct s_PXENV_FILE_API_CHECK *file_api_check ) {
	DBG ( "PXENV_FILE_API_CHECK" );

	if ( file_api_check->Magic != 0x91d447b2 ) {
		file_api_check->Status = PXENV_STATUS_BAD_FUNC;
		return PXENV_EXIT_FAILURE;
	} else if ( file_api_check->Size <
		    sizeof(struct s_PXENV_FILE_API_CHECK) ) {
		file_api_check->Status = PXENV_STATUS_OUT_OF_RESOURCES;
		return PXENV_EXIT_FAILURE;
	} else {
		file_api_check->Status   = PXENV_STATUS_SUCCESS;
		file_api_check->Size     = sizeof(struct s_PXENV_FILE_API_CHECK);
		file_api_check->Magic    = 0xe9c17b20;
		file_api_check->Provider = 0x45585067; /* "gPXE" */
		file_api_check->APIMask  = 0x0000007f; /* Functions e0-e6 */
		/* Check to see if we have a PXE exit hook */
		if ( pxe_exit_hook.segment | pxe_exit_hook.offset )
			/* Function e7, also */
			file_api_check->APIMask |= 0x00000080;
		file_api_check->Flags    = 0;	       /* None defined */
		return PXENV_EXIT_SUCCESS;
	}
}

/**
 * FILE EXIT HOOK
 *
 * @v file_exit_hook			Pointer to a struct
 *					s_PXENV_FILE_EXIT_HOOK
 * @v s_PXENV_FILE_EXIT_HOOK::Hook	SEG16:OFF16 to jump to
 * @ret #PXENV_EXIT_SUCCESS		Successfully set hook
 * @ret #PXENV_EXIT_FAILURE		We're not an NBP build
 * @ret s_PXENV_FILE_EXIT_HOOK::Status	PXE status code
 *
 */
PXENV_EXIT_t pxenv_file_exit_hook ( struct s_PXENV_FILE_EXIT_HOOK
					*file_exit_hook ) {
	DBG ( "PXENV_FILE_EXIT_HOOK" );

	/* Check to see if we have a PXE exit hook */
	if ( pxe_exit_hook.segment | pxe_exit_hook.offset ) {
		/* We'll jump to the specified SEG16:OFF16 during exit */
		pxe_exit_hook.segment = file_exit_hook->Hook.segment;
		pxe_exit_hook.offset = file_exit_hook->Hook.offset;
		file_exit_hook->Status = PXENV_STATUS_SUCCESS;
		return PXENV_EXIT_SUCCESS;
	}

	DBG ( " not NBP" );
	file_exit_hook->Status = PXENV_STATUS_UNSUPPORTED;
	return PXENV_EXIT_FAILURE;
}