pxe_file.c

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/** @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;
}