efi_autoexec.c

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/*
 * Copyright (C) 2021 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.
 *
 * You can also choose to distribute this program under the terms of
 * the Unmodified Binary Distribution Licence (as given in the file
 * COPYING.UBDL), provided that you have satisfied its requirements.
 */

FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );

#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <ipxe/image.h>
#include <ipxe/init.h>
#include <ipxe/in.h>
#include <ipxe/efi/efi.h>
#include <ipxe/efi/efi_autoexec.h>
#include <ipxe/efi/Protocol/PxeBaseCode.h>
#include <ipxe/efi/Protocol/SimpleFileSystem.h>
#include <ipxe/efi/Guid/FileInfo.h>

/** @file
 *
 * EFI autoexec script
 *
 */

/** Autoexec script filename */
static wchar_t efi_autoexec_wname[] = L"autoexec.ipxe";

/** Autoexec script image name */
static char efi_autoexec_name[] = "autoexec.ipxe";

/** Autoexec script (if any) */
static void *efi_autoexec;

/** Autoexec script length */
static size_t efi_autoexec_len;

/**
 * Load autoexec script from filesystem
 *
 * @v device            Device handle
 * @ret rc              Return status code
 */
static int efi_autoexec_filesystem ( EFI_HANDLE device ) {
        EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
        union {
                void *interface;
                EFI_SIMPLE_FILE_SYSTEM_PROTOCOL *fs;
        } u;
        struct {
                EFI_FILE_INFO info;
                CHAR16 name[ sizeof ( efi_autoexec_wname ) /
                             sizeof ( efi_autoexec_wname[0] ) ];
        } info;
        EFI_FILE_PROTOCOL *root;
        EFI_FILE_PROTOCOL *file;
        UINTN size;
        VOID *data;
        EFI_STATUS efirc;
        int rc;

        /* Open simple file system protocol */
        if ( ( efirc = bs->OpenProtocol ( device,
                                          &efi_simple_file_system_protocol_guid,
                                          &u.interface, efi_image_handle,
                                          device,
                                          EFI_OPEN_PROTOCOL_GET_PROTOCOL ))!=0){
                rc = -EEFI ( efirc );
                DBGC ( device, "EFI %s has no filesystem instance: %s\n",
                       efi_handle_name ( device ), strerror ( rc ) );
                goto err_filesystem;
        }

        /* Open root directory */
        if ( ( efirc = u.fs->OpenVolume ( u.fs, &root ) ) != 0 ) {
                rc = -EEFI ( efirc );
                DBGC ( device, "EFI %s could not open volume: %s\n",
                       efi_handle_name ( device ), strerror ( rc ) );
                goto err_volume;
        }

        /* Open autoexec script */
        if ( ( efirc = root->Open ( root, &file, efi_autoexec_wname,
                                    EFI_FILE_MODE_READ, 0 ) ) != 0 ) {
                rc = -EEFI ( efirc );
                DBGC ( device, "EFI %s has no %ls: %s\n",
                       efi_handle_name ( device ), efi_autoexec_wname,
                       strerror ( rc ) );
                goto err_open;
        }

        /* Get file information */
        size = sizeof ( info );
        if ( ( efirc = file->GetInfo ( file, &efi_file_info_id, &size,
                                       &info ) ) != 0 ) {
                rc = -EEFI ( efirc );
                DBGC ( device, "EFI %s could not get %ls info: %s\n",
                       efi_handle_name ( device ), efi_autoexec_wname,
                       strerror ( rc ) );
                goto err_getinfo;
        }
        size = info.info.FileSize;

        /* Ignore zero-length files */
        if ( ! size ) {
                rc = -EINVAL;
                DBGC ( device, "EFI %s has zero-length %ls\n",
                       efi_handle_name ( device ), efi_autoexec_wname );
                goto err_empty;
        }

        /* Allocate temporary copy */
        if ( ( efirc = bs->AllocatePool ( EfiBootServicesData, size,
                                          &data ) ) != 0 ) {
                rc = -EEFI ( efirc );
                DBGC ( device, "EFI %s could not allocate %ls: %s\n",
                       efi_handle_name ( device ), efi_autoexec_wname,
                       strerror ( rc ) );
                goto err_alloc;
        }

        /* Read file */
        if ( ( efirc = file->Read ( file, &size, data ) ) != 0 ) {
                rc = -EEFI ( efirc );
                DBGC ( device, "EFI %s could not read %ls: %s\n",
                       efi_handle_name ( device ), efi_autoexec_wname,
                       strerror ( rc ) );
                goto err_read;
        }

        /* Record autoexec script */
        efi_autoexec = data;
        efi_autoexec_len = size;
        data = NULL;
        DBGC ( device, "EFI %s found %ls\n",
               efi_handle_name ( device ), efi_autoexec_wname );

        /* Success */
        rc = 0;

 err_read:
        if ( data )
                bs->FreePool ( data );
 err_alloc:
 err_empty:
 err_getinfo:
        file->Close ( file );
 err_open:
        root->Close ( root );
 err_volume:
        bs->CloseProtocol ( device, &efi_simple_file_system_protocol_guid,
                            efi_image_handle, device );
 err_filesystem:
        return rc;
}

/**
 * Load autoexec script from TFTP server
 *
 * @v device            Device handle
 * @ret rc              Return status code
 */
static int efi_autoexec_tftp ( EFI_HANDLE device ) {
        EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
        union {
                void *interface;
                EFI_PXE_BASE_CODE_PROTOCOL *pxe;
        } u;
        EFI_PXE_BASE_CODE_MODE *mode;
        EFI_PXE_BASE_CODE_PACKET *packet;
        union {
                struct in_addr in;
                EFI_IP_ADDRESS ip;
        } server;
        size_t filename_max;
        char *filename;
        char *sep;
        UINT64 size;
        VOID *data;
        EFI_STATUS efirc;
        int rc;

        /* Open PXE base code protocol */
        if ( ( efirc = bs->OpenProtocol ( device,
                                          &efi_pxe_base_code_protocol_guid,
                                          &u.interface, efi_image_handle,
                                          device,
                                          EFI_OPEN_PROTOCOL_GET_PROTOCOL ))!=0){
                rc = -EEFI ( efirc );
                DBGC ( device, "EFI %s has no PXE base code instance: %s\n",
                       efi_handle_name ( device ), strerror ( rc ) );
                goto err_pxe;
        }

        /* Do not attempt to parse DHCPv6 packets */
        mode = u.pxe->Mode;
        if ( mode->UsingIpv6 ) {
                rc = -ENOTSUP;
                DBGC ( device, "EFI %s has IPv6 PXE base code\n",
                       efi_handle_name ( device ) );
                goto err_ipv6;
        }

        /* Identify relevant reply packet */
        if ( mode->PxeReplyReceived &&
             mode->PxeReply.Dhcpv4.BootpBootFile[0] ) {
                /* Use boot filename if present in PXE reply */
                DBGC ( device, "EFI %s using PXE reply filename\n",
                       efi_handle_name ( device ) );
                packet = &mode->PxeReply;
        } else if ( mode->DhcpAckReceived &&
                    mode->DhcpAck.Dhcpv4.BootpBootFile[0] ) {
                /* Otherwise, use boot filename if present in DHCPACK */
                DBGC ( device, "EFI %s using DHCPACK filename\n",
                       efi_handle_name ( device ) );
                packet = &mode->DhcpAck;
        } else if ( mode->ProxyOfferReceived &&
                    mode->ProxyOffer.Dhcpv4.BootpBootFile[0] ) {
                /* Otherwise, use boot filename if present in ProxyDHCPOFFER */
                DBGC ( device, "EFI %s using ProxyDHCPOFFER filename\n",
                       efi_handle_name ( device ) );
                packet = &mode->ProxyOffer;
        } else {
                /* No boot filename available */
                rc = -ENOENT;
                DBGC ( device, "EFI %s has no PXE boot filename\n",
                       efi_handle_name ( device ) );
                goto err_packet;
        }

        /* Allocate filename */
        filename_max = ( sizeof ( packet->Dhcpv4.BootpBootFile )
                         + ( sizeof ( efi_autoexec_name ) - 1 /* NUL */ )
                         + 1 /* NUL */ );
        filename = zalloc ( filename_max );
        if ( ! filename ) {
                rc = -ENOMEM;
                goto err_filename;
        }

        /* Extract next-server address and boot filename */
        memset ( &server, 0, sizeof ( server ) );
        memcpy ( &server.in, packet->Dhcpv4.BootpSiAddr,
                 sizeof ( server.in ) );
        memcpy ( filename, packet->Dhcpv4.BootpBootFile,
                 sizeof ( packet->Dhcpv4.BootpBootFile ) );

        /* Update filename to autoexec script name */
        sep = strrchr ( filename, '/' );
        if ( ! sep )
                sep = strrchr ( filename, '\\' );
        if ( ! sep )
                sep = ( filename - 1 );
        strcpy ( ( sep + 1 ), efi_autoexec_name );

        /* Get file size */
        if ( ( efirc = u.pxe->Mtftp ( u.pxe,
                                      EFI_PXE_BASE_CODE_TFTP_GET_FILE_SIZE,
                                      NULL, FALSE, &size, NULL, &server.ip,
                                      ( ( UINT8 * ) filename ), NULL,
                                      FALSE ) ) != 0 ) {
                rc = -EEFI ( efirc );
                DBGC ( device, "EFI %s could not get size of %s:%s: %s\n",
                       efi_handle_name ( device ), inet_ntoa ( server.in ),
                       filename, strerror ( rc ) );
                goto err_size;
        }

        /* Ignore zero-length files */
        if ( ! size ) {
                rc = -EINVAL;
                DBGC ( device, "EFI %s has zero-length %s:%s\n",
                       efi_handle_name ( device ), inet_ntoa ( server.in ),
                       filename );
                goto err_empty;
        }

        /* Allocate temporary copy */
        if ( ( efirc = bs->AllocatePool ( EfiBootServicesData, size,
                                          &data ) ) != 0 ) {
                rc = -EEFI ( efirc );
                DBGC ( device, "EFI %s could not allocate %s:%s: %s\n",
                       efi_handle_name ( device ), inet_ntoa ( server.in ),
                       filename, strerror ( rc ) );
                goto err_alloc;
        }

        /* Download file */
        if ( ( efirc = u.pxe->Mtftp ( u.pxe, EFI_PXE_BASE_CODE_TFTP_READ_FILE,
                                      data, FALSE, &size, NULL, &server.ip,
                                      ( ( UINT8 * ) filename ), NULL,
                                      FALSE ) ) != 0 ) {
                rc = -EEFI ( efirc );
                DBGC ( device, "EFI %s could not download %s:%s: %s\n",
                       efi_handle_name ( device ), inet_ntoa ( server.in ),
                       filename, strerror ( rc ) );
                goto err_download;
        }

        /* Record autoexec script */
        efi_autoexec = data;
        efi_autoexec_len = size;
        data = NULL;
        DBGC ( device, "EFI %s found %s:%s\n", efi_handle_name ( device ),
               inet_ntoa ( server.in ), filename );

        /* Success */
        rc = 0;

 err_download:
        if ( data )
                bs->FreePool ( data );
 err_alloc:
 err_empty:
 err_size:
        free ( filename );
 err_filename:
 err_packet:
 err_ipv6:
        bs->CloseProtocol ( device, &efi_pxe_base_code_protocol_guid,
                            efi_image_handle, device );
 err_pxe:
        return rc;
}

/**
 * Load autoexec script
 *
 * @v device            Device handle
 * @ret rc              Return status code
 */
int efi_autoexec_load ( EFI_HANDLE device ) {
        int rc;

        /* Sanity check */
        assert ( efi_autoexec == NULL );
        assert ( efi_autoexec_len == 0 );

        /* Try loading from file system, if supported */
        if ( ( rc = efi_autoexec_filesystem ( device ) ) == 0 )
                return 0;

        /* Try loading via TFTP, if supported */
        if ( ( rc = efi_autoexec_tftp ( device ) ) == 0 )
                return 0;

        return -ENOENT;
}

/**
 * Register autoexec script
 *
 */
static void efi_autoexec_startup ( void ) {
        EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
        EFI_HANDLE device = efi_loaded_image->DeviceHandle;
        struct image *image;

        /* Do nothing if we have no autoexec script */
        if ( ! efi_autoexec )
                return;

        /* Create autoexec image */
        image = image_memory ( efi_autoexec_name,
                               virt_to_user ( efi_autoexec ),
                               efi_autoexec_len );
        if ( ! image ) {
                DBGC ( device, "EFI %s could not create %s\n",
                       efi_handle_name ( device ), efi_autoexec_name );
                return;
        }
        DBGC ( device, "EFI %s registered %s\n",
               efi_handle_name ( device ), efi_autoexec_name );

        /* Free temporary copy */
        bs->FreePool ( efi_autoexec );
        efi_autoexec = NULL;
}

/** Autoexec script startup function */
struct startup_fn efi_autoexec_startup_fn __startup_fn ( STARTUP_NORMAL ) = {
        .name = "efi_autoexec",
        .startup = efi_autoexec_startup,
};