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legacy/libisofs_outdated/attic/libisofs/eltorito.c

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#include "libisofs.h"
#include "eltorito.h"
#include "volume.h"
#include "util.h"
#include "messages.h"
#include <assert.h>
#include <malloc.h>
#include <time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <string.h>
#include <stdio.h>
#include <fcntl.h>
/**
* This table should be written with accuracy values at offset
* 8 of boot image, when used ISOLINUX boot loader
*/
struct boot_info_table {
uint8_t bi_pvd BP(1, 4); /* LBA of primary volume descriptor */
uint8_t bi_file BP(5, 8); /* LBA of boot file */
uint8_t bi_length BP(9, 12); /* Length of boot file */
uint8_t bi_csum BP(13, 16); /* Checksum of boot file */
uint8_t bi_reserved BP(17, 56); /* Reserved */
};
struct partition_desc {
uint8_t boot_ind;
uint8_t begin_chs[3];
uint8_t type;
uint8_t end_chs[3];
uint8_t start[4];
uint8_t size[4];
};
struct hard_disc_mbr {
uint8_t code_area[440];
uint8_t opt_disk_sg[4];
uint8_t pad[2];
struct partition_desc partition[4];
uint8_t sign1;
uint8_t sign2;
};
static void
el_torito_image_free(struct el_torito_boot_image *image)
{
assert(image);
/* unref image node */
iso_tree_free((struct iso_tree_node*)image->node);
free(image);
}
static struct iso_tree_node_boot*
create_boot_image_node(struct iso_tree_node_file *image)
{
struct iso_tree_node_boot *boot;
struct iso_tree_node_dir *parent;
assert(image);
boot = calloc(1, sizeof(struct iso_tree_node_boot));
boot->node.attrib = image->node.attrib;
boot->node.type = LIBISO_NODE_BOOT;
boot->node.name = strdup(image->node.name);
boot->node.hide_flags = image->node.hide_flags;
boot->node.refcount = 2; /* mine and tree */
boot->loc.path = strdup(image->loc.path);
boot->img = 1; /* it refers to image */
/* replace iso_tree_node_file with the image */
parent = image->node.parent;
iso_tree_node_remove(parent, (struct iso_tree_node*)image);
iso_tree_add_child(parent, (struct iso_tree_node*) boot);
return boot;
}
static struct el_torito_boot_image *
create_image(const char *path,
enum eltorito_boot_media_type type)
{
struct stat attrib;
struct el_torito_boot_image *boot;
int boot_media_type = 0;
int load_sectors = 0; /* number of sector to load */
unsigned char partition_type = 0;
if (stat(path, &attrib)) {
iso_msg_sorry(LIBISO_EL_TORITO_WRONG_IMG, "Can't access file.");
libisofs_errno = NO_FILE;
return NULL;
}
if ( !S_ISREG(attrib.st_mode) ) {
iso_msg_sorry(LIBISO_EL_TORITO_WRONG_IMG,
"We can only create boot images from regular files");
libisofs_errno = ELTORITO_WRONG_IMAGE;
return NULL;
}
switch (type) {
case ELTORITO_FLOPPY_EMUL:
switch (attrib.st_size) {
case 1200 * 1024:
boot_media_type = 1; /* 1.2 meg diskette */
break;
case 1440 * 1024:
boot_media_type = 2; /* 1.44 meg diskette */
break;
case 2880 * 1024:
boot_media_type = 3; /* 2.88 meg diskette */
break;
default:
{
char msg[72];
sprintf(msg, "Invalid image size %d Kb. Must be one of 1.2, 1.44"
"or 2.88 Mb", (int) attrib.st_size / 1024);
iso_msg_sorry(LIBISO_EL_TORITO_WRONG_IMG, msg);
libisofs_errno = ELTORITO_WRONG_IMAGE_SIZE;
return NULL;
}
break;
}
/* it seems that for floppy emulation we need to load
* a single sector (512b) */
load_sectors = 1;
break;
case ELTORITO_HARD_DISC_EMUL:
{
size_t i;
int fd;
struct hard_disc_mbr mbr;
int used_partition;
/* read the MBR on disc and get the type of the partition */
fd = open(path, O_RDONLY);
if ( fd == -1 ) {
iso_msg_sorry(LIBISO_EL_TORITO_WRONG_IMG, "Can't open image file.");
libisofs_errno = NO_READ_ACCESS;
return NULL;
}
if ( read(fd, &mbr, sizeof(mbr)) ) {
iso_msg_sorry(LIBISO_EL_TORITO_WRONG_IMG,
"Can't read MBR from image file.");
libisofs_errno = ELTORITO_WRONG_IMAGE;
close(fd);
return NULL;
}
close(fd);
/* check valid MBR signature */
if ( mbr.sign1 != 0x55 || mbr.sign2 != 0xAA ) {
iso_msg_sorry(LIBISO_EL_TORITO_WRONG_IMG,
"Invalid MBR. Wrong signature.");
libisofs_errno = ELTORITO_WRONG_IMAGE;
return NULL;
}
/* ensure single partition */
used_partition = -1;
for (i = 0; i < 4; ++i) {
if (mbr.partition[i].type != 0) {
/* it's an used partition */
if (used_partition != -1) {
char msg[72];
sprintf(msg, "Invalid MBR. At least 2 partitions: %d and "
"%d, are being used\n", used_partition, i);
iso_msg_sorry(LIBISO_EL_TORITO_WRONG_IMG, msg);
libisofs_errno = ELTORITO_WRONG_IMAGE;
return NULL;
} else
used_partition = i;
}
}
partition_type = mbr.partition[used_partition].type;
}
boot_media_type = 4;
/* only load the MBR */
load_sectors = 1;
break;
case ELTORITO_NO_EMUL:
boot_media_type = 0;
break;
}
boot = calloc(1, sizeof(struct el_torito_boot_image));
boot->bootable = 1;
boot->type = boot_media_type;
boot->load_size = load_sectors;
boot->partition_type = partition_type;
return boot;
}
/* parent and name can be null */
static struct iso_tree_node_boot*
create_boot_catalog_node(struct iso_tree_node_dir *parent,
const char *name)
{
struct iso_tree_node_boot *boot;
assert( (parent && name) || (!parent && !name) );
boot = calloc(1, sizeof(struct iso_tree_node_boot));
boot->node.attrib.st_mode = S_IFREG | 0444;
boot->node.attrib.st_atime =
boot->node.attrib.st_mtime =
boot->node.attrib.st_ctime = time(NULL);
boot->node.attrib.st_size = 2048;
boot->node.type = LIBISO_NODE_BOOT;
boot->node.name = name ? strdup(name) : NULL;
boot->node.refcount = 1; /* mine */
if (parent) {
boot->node.refcount++; /* add tree ref */
iso_tree_add_child(parent, (struct iso_tree_node*) boot);
}
return boot;
}
struct el_torito_boot_image*
iso_volume_set_boot_image(struct iso_volume *volume,
struct iso_tree_node *image,
enum eltorito_boot_media_type type,
struct iso_tree_node_dir *dir,
char *name)
{
struct el_torito_boot_image *boot_image;
struct iso_tree_node_boot *cat_node;
struct el_torito_boot_catalog *catalog;
struct iso_tree_node_file *imgfile;
assert(volume && !volume->bootcat);
assert(image && ISO_ISREG(image));
assert(dir && name);
imgfile = (struct iso_tree_node_file*)image;
if (image->procedence == LIBISO_PREVIMG) {
/* FIXME mmm, what to do here? */
iso_msg_sorry(LIBISO_EL_TORITO_WRONG_IMG, "Can't use prev. image files "
"as boot images");
return NULL;
}
boot_image = create_image(imgfile->loc.path, type);
if ( !boot_image )
return NULL;
/* create image node */
boot_image->node = create_boot_image_node(imgfile);
/* creates the catalog with the given default image */
catalog = malloc(sizeof(struct el_torito_boot_catalog));
if (!catalog) {
el_torito_image_free(boot_image);
return NULL;
}
catalog->image = boot_image;
/* add catalog file */
cat_node = create_boot_catalog_node(dir, name);
catalog->node = cat_node;
volume->bootcat = catalog;
return boot_image;
}
struct el_torito_boot_image*
iso_volume_set_boot_image_hidden(struct iso_volume *volume, const char* path,
enum eltorito_boot_media_type type)
{
struct el_torito_boot_image *boot_image;
struct iso_tree_node_boot *cat_node;
struct el_torito_boot_catalog *catalog;
assert(volume && !volume->bootcat);
assert(path);
boot_image = create_image(path, type);
if ( !boot_image )
return NULL;
/* create image node */
{
struct iso_tree_node_boot *boot;
boot = calloc(1, sizeof(struct iso_tree_node_boot));
/* we assume the stat won't fail, as we already stat the same file above */
stat(path, &boot->node.attrib);
boot->node.type = LIBISO_NODE_BOOT;
boot->node.refcount = 1; /* mine */
boot->loc.path = strdup(path);
boot->img = 1; /* it refers to image */
boot_image->node = boot;
}
/* creates the catalog with the given default image */
catalog = malloc(sizeof(struct el_torito_boot_catalog));
if (!catalog) {
el_torito_image_free(boot_image);
return NULL;
}
catalog->image = boot_image;
/* add catalog file */
cat_node = create_boot_catalog_node(NULL, NULL);
catalog->node = cat_node;
volume->bootcat = catalog;
return boot_image;
}
struct el_torito_boot_image*
iso_volume_get_boot_image(struct iso_volume *volume,
struct iso_tree_node **imgnode,
struct iso_tree_node **catnode)
{
struct el_torito_boot_catalog *catalog;
assert(volume);
catalog = volume->bootcat;
if (!catalog)
return NULL;
if (imgnode)
*imgnode = (struct iso_tree_node*)catalog->image->node;
if (catnode)
*catnode = (struct iso_tree_node*)catalog->node;
return catalog->image;
}
void
iso_volume_remove_boot_image(struct iso_volume *volume)
{
struct el_torito_boot_catalog *catalog;
struct iso_tree_node *catnode;
struct iso_tree_node *imgnode;
assert(volume);
catalog = volume->bootcat;
if (!catalog)
return;
/* remove node from tree */
catnode = (struct iso_tree_node*)catalog->node;
if (catnode->parent)
iso_tree_node_remove(catnode->parent, catnode);
/* remove image from tree */
imgnode = (struct iso_tree_node*)catalog->image->node;
if (imgnode->parent)
iso_tree_node_remove(imgnode->parent, imgnode);
/* remove catalog */
el_torito_boot_catalog_free(catalog);
volume->bootcat = NULL;
}
void
el_torito_set_load_seg(struct el_torito_boot_image *bootimg, int segment)
{
if (bootimg->type != ELTORITO_NO_EMUL)
return;
bootimg->load_seg = segment;
}
void
el_torito_set_load_size(struct el_torito_boot_image *bootimg, int sectors)
{
if (bootimg->type != ELTORITO_NO_EMUL)
return;
bootimg->load_size = sectors;
}
void
el_torito_set_no_bootable(struct el_torito_boot_image *bootimg)
{
bootimg->bootable = 0;
}
void
el_torito_patch_isolinux_image(struct el_torito_boot_image *bootimg)
{
bootimg->isolinux = 1;
}
void el_torito_boot_catalog_free(struct el_torito_boot_catalog *cat)
{
assert(cat);
el_torito_image_free(cat->image);
iso_tree_free((struct iso_tree_node*)cat->node);
free(cat);
}
/**
* Write the Boot Record Volume Descriptor
*/
void
el_torito_write_boot_vol_desc(struct ecma119_write_target *t, uint8_t *buf)
{
struct el_torito_boot_catalog *cat = t->catalog;
struct ecma119_boot_rec_vol_desc *vol =
(struct ecma119_boot_rec_vol_desc*)buf;
assert(cat);
vol->vol_desc_type[0] = 0;
memcpy(vol->std_identifier, "CD001", 5);
vol->vol_desc_version[0] = 1;
memcpy(vol->boot_sys_id, "EL TORITO SPECIFICATION", 23);
iso_lsb(vol->boot_catalog, t->catblock, 4);
}
static void
write_validation_entry(struct ecma119_write_target *t, uint8_t *buf)
{
size_t i;
int checksum;
struct el_torito_validation_entry *ve =
(struct el_torito_validation_entry*)buf;
ve->header_id[0] = 1;
ve->platform_id[0] = 0; /* 0: 80x86, 1: PowerPC, 2: Mac */
ve->key_byte1[0] = 0x55;
ve->key_byte2[0] = 0xAA;
/* calculate the checksum, to ensure sum of all words is 0 */
checksum = 0;
for (i = 0; i < sizeof(struct el_torito_validation_entry); i += 2) {
checksum -= buf[i];
checksum -= (buf[i] << 8);
}
iso_lsb(ve->checksum, checksum, 2);
}
static void
patch_boot_image(uint8_t *buf, struct ecma119_write_target *t, ssize_t imgsize)
{
struct boot_info_table *info;
uint32_t checksum;
ssize_t offset;
memset(&info, 0, sizeof(info));
/* compute checksum, as the the sum of all 32 bit words in boot image
* from offset 64 */
checksum = 0;
offset = (ssize_t) 64;
while (offset < imgsize) {
checksum += iso_read_lsb(buf + offset, 4);
offset += 4;
}
if (offset != imgsize) {
/* file length not multiple of 4 */
iso_msg_warn(LIBISO_ISOLINUX_CANT_PATCH,
"Unexpected isolinux image length. Patch might not work.");
}
/* patch boot info table */
info = (struct boot_info_table*)(buf + 8);
memset(info, 0, sizeof(struct boot_info_table));
iso_lsb(info->bi_pvd, t->ms_block + 16, 4);
iso_lsb(info->bi_file, t->imgblock, 4);
iso_lsb(info->bi_length, imgsize, 4);
iso_lsb(info->bi_csum, checksum, 4);
}
static void
write_boot_image(uint8_t *buf, struct ecma119_write_target *t)
{
ssize_t imgsize;
struct el_torito_boot_image *image;
image = t->catalog->image;
imgsize= image->node->node.attrib.st_size;
/* copy image contents to memory buffer */
if (image->node->node.procedence == LIBISO_PREVIMG) {
int block, nblocks;
uint8_t *memloc;
assert(t->src);
block = 0;
memloc = buf;
nblocks = imgsize ? div_up(imgsize, 2048) : 1;
while (block < nblocks) {
if (t->src->read_block(t->src,
image->node->loc.block + block, memloc)) {
iso_msg_sorry(LIBISO_CANT_READ_IMG,
"Unable to read boot image from previous image.");
break; /* exit loop */
}
memloc += 2048;
++block;
}
} else {
int fd;
ssize_t nread, tread;
uint8_t *memloc;
const char *path = image->node->loc.path;
memloc = buf;
fd = open(path, O_RDONLY);
if (fd == -1) {
iso_msg_sorry(LIBISO_CANT_READ_FILE,
"Can't open boot image file for reading. Skipping");
return;
}
tread = 0;
while (tread < imgsize) {
nread = read(fd, memloc, t->block_size);
if (nread <= 0) {
iso_msg_sorry(LIBISO_CANT_READ_FILE,
"Problem reading boot image file. Skipping");
break; /* exit loop */
}
tread += nread;
memloc += nread;
}
close(fd);
}
if (image->isolinux) {
/* we need to patch the image */
patch_boot_image(buf, t, imgsize);
}
}
/**
* Write one section entry.
* Currently this is used only for default image (the only supported just now)
*/
static void
write_section_entry(uint8_t *buf, struct ecma119_write_target *t)
{
struct el_torito_boot_image *img;
struct el_torito_section_entry *se =
(struct el_torito_section_entry*)buf;
img = t->catalog->image;
assert(img);
se->boot_indicator[0] = img->bootable ? 0x88 : 0x00;
se->boot_media_type[0] = img->type;
iso_lsb(se->load_seg, img->load_seg, 2);
se->system_type[0] = img->partition_type;
iso_lsb(se->sec_count, img->load_size, 2);
iso_lsb(se->block, t->imgblock, 4);
}
/**
* Write El-Torito Boot Catalog plus image
*/
static void
write_catalog(struct ecma119_write_target *t, uint8_t *buf)
{
struct el_torito_boot_catalog *cat = t->catalog;
assert(cat);
assert(cat->image);
write_validation_entry(t, buf);
/* write default entry */
write_section_entry(buf + 32, t);
write_boot_image(buf + 2048, t);
}
void
el_torito_wr_boot_vol_desc(struct ecma119_write_target *t, uint8_t *buf)
{
assert(t->catalog);
ecma119_start_chunking(t,
el_torito_write_boot_vol_desc,
2048,
buf);
}
void
el_torito_wr_catalog(struct ecma119_write_target *t, uint8_t *buf)
{
off_t size;
off_t imgsize;
assert(t->catalog);
/*
* Note that when this is called, we need to write el-torito info to
* image. Note, however, that the image could come from a previous session
* and maybe we don't know its size
*/
imgsize = t->catalog->image->node->node.attrib.st_size;
if (imgsize == 0) {
iso_msg_warn(LIBISO_EL_TORITO_BLIND_COPY,
"Can get boot image size, only one block will be copied");
imgsize = 2048;
}
size = 2048 + div_up(imgsize, t->block_size);
ecma119_start_chunking(t,
write_catalog,
size,
buf);
}
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