efi_local.c

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/*
 * Copyright (C) 2016 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 (at your option) 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 );
FILE_SECBOOT ( PERMITTED );

#include <string.h>
#include <strings.h>
#include <stdio.h>
#include <errno.h>
#include <assert.h>
#include <ipxe/refcnt.h>
#include <ipxe/malloc.h>
#include <ipxe/xfer.h>
#include <ipxe/open.h>
#include <ipxe/uri.h>
#include <ipxe/iobuf.h>
#include <ipxe/process.h>
#include <ipxe/errortab.h>
#include <ipxe/efi/efi.h>
#include <ipxe/efi/efi_strings.h>
#include <ipxe/efi/efi_path.h>
#include <ipxe/efi/Protocol/SimpleFileSystem.h>
#include <ipxe/efi/Guid/FileInfo.h>
#include <ipxe/efi/Guid/FileSystemInfo.h>

/** @file
 *
 * EFI local file access
 *
 */

/* Disambiguate the various error causes */
#define EINFO_EEFI_OPEN                                                 \
        __einfo_uniqify ( EINFO_EPLATFORM, 0x01, "Could not open" )
#define EINFO_EEFI_OPEN_NOT_FOUND                                       \
        __einfo_platformify ( EINFO_EEFI_OPEN, EFI_NOT_FOUND,           \
                              "Not found" )
#define EEFI_OPEN_NOT_FOUND                                             \
        __einfo_error ( EINFO_EEFI_OPEN_NOT_FOUND )
#define EEFI_OPEN( efirc ) EPLATFORM ( EINFO_EEFI_OPEN, efirc,          \
                                       EEFI_OPEN_NOT_FOUND )

/** Download blocksize */
#define EFI_LOCAL_BLKSIZE 4096

/** An EFI local file */
struct efi_local {
        /** Reference count */
        struct refcnt refcnt;
        /** Data transfer interface */
        struct interface xfer;
        /** Download process */
        struct process process;

        /** Download URI */
        struct uri *uri;
        /** Volume name, or NULL to use loaded image's device */
        const char *volume;
        /** File path */
        const char *path;

        /** EFI root directory */
        EFI_FILE_PROTOCOL *root;
        /** EFI file */
        EFI_FILE_PROTOCOL *file;
        /** Length of file */
        size_t len;
};

/** Human-readable error messages */
struct errortab efi_local_errors[] __errortab = {
        __einfo_errortab ( EINFO_EEFI_OPEN_NOT_FOUND ),
};

/**
 * Free local file
 *
 * @v refcnt            Reference count
 */
static void efi_local_free ( struct refcnt *refcnt ) {
        struct efi_local *local =
                container_of ( refcnt, struct efi_local, refcnt );

        uri_put ( local->uri );
        free ( local );
}

/**
 * Close local file
 *
 * @v local             Local file
 * @v rc                Reason for close
 */
static void efi_local_close ( struct efi_local *local, int rc ) {

        /* Stop process */
        process_del ( &local->process );

        /* Shut down data transfer interface */
        intf_shutdown ( &local->xfer, rc );

        /* Close EFI file */
        if ( local->file ) {
                local->file->Close ( local->file );
                local->file = NULL;
        }

        /* Close EFI root directory */
        if ( local->root ) {
                local->root->Close ( local->root );
                local->root = NULL;
        }
}

/**
 * Check for matching volume name
 *
 * @v local             Local file
 * @v device            Device handle
 * @v root              Root filesystem handle
 * @v volume            Volume name
 * @ret rc              Return status code
 */
static int efi_local_check_volume_name ( struct efi_local *local,
                                         EFI_HANDLE device,
                                         EFI_FILE_PROTOCOL *root,
                                         const char *volume ) {
        EFI_FILE_SYSTEM_INFO *info;
        UINTN size;
        char *label;
        EFI_STATUS efirc;
        int rc;

        /* Get length of file system information */
        size = 0;
        root->GetInfo ( root, &efi_file_system_info_id, &size, NULL );

        /* Allocate file system information */
        info = malloc ( size );
        if ( ! info ) {
                rc = -ENOMEM;
                goto err_alloc_info;
        }

        /* Get file system information */
        if ( ( efirc = root->GetInfo ( root, &efi_file_system_info_id, &size,
                                       info ) ) != 0 ) {
                rc = -EEFI ( efirc );
                DBGC ( local, "LOCAL %p could not get file system info on %s: "
                       "%s\n", local, efi_handle_name ( device ),
                       strerror ( rc ) );
                goto err_get_info;
        }
        DBGC2 ( local, "LOCAL %p found %s with label \"%ls\"\n",
                local, efi_handle_name ( device ), info->VolumeLabel );

        /* Construct volume label for comparison */
        if ( asprintf ( &label, "%ls", info->VolumeLabel ) < 0 ) {
                rc = -ENOMEM;
                goto err_alloc_label;
        }

        /* Compare volume label */
        if ( strcasecmp ( volume, label ) != 0 ) {
                rc = -ENOENT;
                goto err_compare;
        }

        /* Success */
        rc = 0;

 err_compare:
        free ( label );
 err_alloc_label:
 err_get_info:
        free ( info );
 err_alloc_info:
        return rc;
}

/**
 * Open root filesystem
 *
 * @v local             Local file
 * @v device            Device handle
 * @v root              Root filesystem handle to fill in
 * @ret rc              Return status code
 */
static int efi_local_open_root ( struct efi_local *local, EFI_HANDLE device,
                                 EFI_FILE_PROTOCOL **root ) {
        EFI_SIMPLE_FILE_SYSTEM_PROTOCOL *fs;
        EFI_STATUS efirc;
        int rc;

        /* Open file system protocol */
        if ( ( rc = efi_open ( device, &efi_simple_file_system_protocol_guid,
                               &fs ) ) != 0 ) {
                DBGC ( local, "LOCAL %p could not open filesystem on %s: %s\n",
                       local, efi_handle_name ( device ), strerror ( rc ) );
                return rc;
        }

        /* Open root directory */
        if ( ( efirc = fs->OpenVolume ( fs, root ) ) != 0 ) {
                rc = -EEFI ( efirc );
                DBGC ( local, "LOCAL %p could not open volume on %s: %s\n",
                       local, efi_handle_name ( device ), strerror ( rc ) );
                return rc;
        }

        return 0;
}

/**
 * Open root filesystem of specified volume
 *
 * @v local             Local file
 * @ret rc              Return status code
 */
static int efi_local_open_volume ( struct efi_local *local ) {
        EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
        EFI_GUID *protocol = &efi_simple_file_system_protocol_guid;
        int ( * check ) ( struct efi_local *local, EFI_HANDLE device,
                          EFI_FILE_PROTOCOL *root, const char *volume );
        const char *volume = local->volume;
        EFI_DEVICE_PATH_PROTOCOL *path;
        EFI_FILE_PROTOCOL *root;
        EFI_HANDLE *handles;
        EFI_HANDLE device;
        UINTN num_handles;
        UINTN i;
        EFI_STATUS efirc;
        int rc;

        /* Identify candidate handles */
        if ( volume ) {
                /* Locate all filesystem handles */
                if ( ( efirc = bs->LocateHandleBuffer ( ByProtocol, protocol,
                                                        NULL, &num_handles,
                                                        &handles ) ) != 0 ) {
                        rc = -EEFI ( efirc );
                        DBGC ( local, "LOCAL %p could not enumerate handles: "
                               "%s\n", local, strerror ( rc ) );
                        return rc;
                }
                check = efi_local_check_volume_name;
        } else {
                /* Locate filesystem from which we were loaded */
                path = efi_loaded_image_path;
                if ( ( efirc = bs->LocateDevicePath ( protocol, &path,
                                                      &device ) ) != 0 ) {
                        rc = -EEFI ( efirc );
                        DBGC ( local, "LOCAL %p could not locate file system "
                               "on %s: %s\n", local,
                               efi_devpath_text ( efi_loaded_image_path ),
                               strerror ( rc ) );
                        return rc;
                }
                handles = &device;
                num_handles = 1;
                check = NULL;
        }

        /* Find matching handle */
        for ( i = 0 ; i < num_handles ; i++ ) {

                /* Get this device handle */
                device = handles[i];

                /* Open root directory */
                if ( ( rc = efi_local_open_root ( local, device, &root ) ) != 0)
                        continue;

                /* Check volume name, if applicable */
                if ( ( check == NULL ) ||
                     ( ( rc = check ( local, device, root, volume ) ) == 0 ) ) {
                        DBGC ( local, "LOCAL %p using %s",
                               local, efi_handle_name ( device ) );
                        if ( volume )
                                DBGC ( local, " with label \"%s\"", volume );
                        DBGC ( local, "\n" );
                        local->root = root;
                        break;
                }

                /* Close root directory */
                root->Close ( root );
        }

        /* Free handles, if applicable */
        if ( volume )
                bs->FreePool ( handles );

        /* Fail if we found no matching handle */
        if ( ! local->root ) {
                DBGC ( local, "LOCAL %p found no matching handle\n", local );
                return -ENOENT;
        }

        return 0;
}

/**
 * Open fully-resolved path
 *
 * @v local             Local file
 * @v resolved          Resolved path
 * @ret rc              Return status code
 */
static int efi_local_open_resolved ( struct efi_local *local,
                                     const char *resolved ) {
        size_t name_len = strlen ( resolved );
        CHAR16 name[ name_len + 1 /* wNUL */ ];
        EFI_FILE_PROTOCOL *file;
        EFI_STATUS efirc;
        int rc;

        /* Construct filename */
        efi_snprintf ( name, ( name_len + 1 /* wNUL */ ), "%s", resolved );

        /* Open file */
        if ( ( efirc = local->root->Open ( local->root, &file, name,
                                           EFI_FILE_MODE_READ, 0 ) ) != 0 ) {
                rc = -EEFI_OPEN ( efirc );
                DBGC ( local, "LOCAL %p could not open \"%s\": %s\n",
                       local, resolved, strerror ( rc ) );
                return rc;
        }
        local->file = file;

        return 0;
}

/**
 * Open specified path
 *
 * @v local             Local file
 * @ret rc              Return status code
 */
static int efi_local_open_path ( struct efi_local *local ) {
        EFI_DEVICE_PATH_PROTOCOL *path = efi_loaded_image->FilePath;
        EFI_DEVICE_PATH_PROTOCOL *next;
        FILEPATH_DEVICE_PATH *fp;
        char base[ efi_path_len ( path ) / 2 /* Cannot exceed this length */ ];
        size_t remaining = sizeof ( base );
        size_t len;
        char *resolved;
        char *tmp;
        int rc;

        /* Construct base path to our own image, if possible */
        memset ( base, 0, sizeof ( base ) );
        tmp = base;
        for ( ; ( next = efi_path_next ( path ) ) ; path = next ) {
                fp = container_of ( path, FILEPATH_DEVICE_PATH, Header );
                len = snprintf ( tmp, remaining, "%ls", fp->PathName );
                assert ( len < remaining );
                tmp += len;
                remaining -= len;
        }
        DBGC2 ( local, "LOCAL %p base path \"%s\"\n",
                local, base );

        /* Convert to sane path separators */
        for ( tmp = base ; *tmp ; tmp++ ) {
                if ( *tmp == '\\' )
                        *tmp = '/';
        }

        /* Resolve path */
        resolved = resolve_path ( base, local->path );
        if ( ! resolved ) {
                rc = -ENOMEM;
                goto err_resolve;
        }

        /* Convert to insane path separators */
        for ( tmp = resolved ; *tmp ; tmp++ ) {
                if ( *tmp == '/' )
                        *tmp = '\\';
        }
        DBGC ( local, "LOCAL %p using \"%s\"\n",
               local, resolved );

        /* Open resolved path */
        if ( ( rc = efi_local_open_resolved ( local, resolved ) ) != 0 )
                goto err_open;

 err_open:
        free ( resolved );
 err_resolve:
        return rc;
}

/**
 * Get file length
 *
 * @v local             Local file
 * @ret rc              Return status code
 */
static int efi_local_len ( struct efi_local *local ) {
        EFI_FILE_PROTOCOL *file = local->file;
        EFI_FILE_INFO *info;
        EFI_STATUS efirc;
        UINTN size;
        int rc;

        /* Get size of file information */
        size = 0;
        file->GetInfo ( file, &efi_file_info_id, &size, NULL );

        /* Allocate file information */
        info = malloc ( size );
        if ( ! info ) {
                rc = -ENOMEM;
                goto err_alloc;
        }

        /* Get file information */
        if ( ( efirc = file->GetInfo ( file, &efi_file_info_id, &size,
                                       info ) ) != 0 ) {
                rc = -EEFI ( efirc );
                DBGC ( local, "LOCAL %p could not get file info: %s\n",
                       local, strerror ( rc ) );
                goto err_info;
        }

        /* Record file length */
        local->len = info->FileSize;

        /* Success */
        rc = 0;

 err_info:
        free ( info );
 err_alloc:
        return rc;
}

/**
 * Local file process
 *
 * @v local             Local file
 */
static void efi_local_step ( struct efi_local *local ) {
        struct io_buffer *iobuf = NULL;
        size_t remaining;
        size_t frag_len;
        UINTN size;
        EFI_STATUS efirc;
        int rc;

        /* Wait until data transfer interface is ready */
        if ( ! xfer_window ( &local->xfer ) )
                return;

        /* Open specified volume root directory, if not yet open */
        if ( ( ! local->root ) &&
             ( ( rc = efi_local_open_volume ( local ) ) != 0 ) )
                goto err;

        /* Open specified file, if not yet open */
        if ( ( ! local->file ) &&
             ( ( rc = efi_local_open_path ( local ) ) != 0 ) )
                goto err;

        /* Get file length, if not yet known */
        if ( ( ! local->len ) &&
             ( ( rc = efi_local_len ( local ) ) != 0 ) )
                goto err;

        /* Presize receive buffer */
        remaining = local->len;
        xfer_seek ( &local->xfer, remaining );
        xfer_seek ( &local->xfer, 0 );

        /* Get file contents */
        while ( remaining ) {

                /* Calculate length for this fragment */
                frag_len = remaining;
                if ( frag_len > EFI_LOCAL_BLKSIZE )
                        frag_len = EFI_LOCAL_BLKSIZE;

                /* Allocate I/O buffer */
                iobuf = xfer_alloc_iob ( &local->xfer, frag_len );
                if ( ! iobuf ) {
                        rc = -ENOMEM;
                        goto err;
                }

                /* Read block */
                size = frag_len;
                if ( ( efirc = local->file->Read ( local->file, &size,
                                                   iobuf->data ) ) != 0 ) {
                        rc = -EEFI ( efirc );
                        DBGC ( local, "LOCAL %p could not read from file: %s\n",
                               local, strerror ( rc ) );
                        goto err;
                }
                assert ( size <= frag_len );
                iob_put ( iobuf, size );

                /* Deliver data */
                if ( ( rc = xfer_deliver_iob ( &local->xfer,
                                               iob_disown ( iobuf ) ) ) != 0 ) {
                        DBGC ( local, "LOCAL %p could not deliver data: %s\n",
                               local, strerror ( rc ) );
                        goto err;
                }

                /* Move to next block */
                remaining -= frag_len;
        }

        /* Close download */
        efi_local_close ( local, 0 );

        return;

 err:
        free_iob ( iobuf );
        efi_local_close ( local, rc );
}

/** Data transfer interface operations */
static struct interface_operation efi_local_operations[] = {
        INTF_OP ( xfer_window_changed, struct efi_local *, efi_local_step ),
        INTF_OP ( intf_close, struct efi_local *, efi_local_close ),
};

/** Data transfer interface descriptor */
static struct interface_descriptor efi_local_xfer_desc =
        INTF_DESC ( struct efi_local, xfer, efi_local_operations );

/** Process descriptor */
static struct process_descriptor efi_local_process_desc =
        PROC_DESC_ONCE ( struct efi_local, process, efi_local_step );

/**
 * Open local file
 *
 * @v xfer              Data transfer interface
 * @v uri               Request URI
 * @ret rc              Return status code
 */
static int efi_local_open ( struct interface *xfer, struct uri *uri ) {
        struct efi_local *local;

        /* Allocate and initialise structure */
        local = zalloc ( sizeof ( *local ) );
        if ( ! local )
                return -ENOMEM;
        ref_init ( &local->refcnt, efi_local_free );
        intf_init ( &local->xfer, &efi_local_xfer_desc, &local->refcnt );
        process_init_stopped ( &local->process, &efi_local_process_desc,
                               &local->refcnt );
        local->uri = uri_get ( uri );
        local->volume = ( ( uri->host && uri->host[0] ) ? uri->host : NULL );
        local->path = ( uri->opaque ? uri->opaque : uri->path );

        /* Start download process */
        process_add ( &local->process );

        /* Attach to parent interface, mortalise self, and return */
        intf_plug_plug ( &local->xfer, xfer );
        ref_put ( &local->refcnt );
        return 0;
}

/** EFI local file URI opener */
struct uri_opener efi_local_uri_opener __uri_opener = {
        .scheme = "file",
        .open   = efi_local_open,
};