[iso] add basic El-Torito image parsing to libcdio

* Based on El-Torito specs found at https://pdos.csail.mit.edu/6.828/2014/readings/boot-cdrom.pdf.
* Follows 7-zip's virtual '[BOOT]/#...' naming conventions (though we don't check for the full name).
* Limited to 8 NoEmul images.

Author: pbatard

src/libcdio/cdio/iso9660.h

@@ -162,6 +162,7 @@ extern enum iso_vd_enum_s {
 extern const char ISO_STANDARD_ID[sizeof("CD001")-1];
 
 #define ISO_STANDARD_ID      "CD001"
+#define EL_TORITO_ID         "EL TORITO SPECIFICATION\0\0\0\0\0\0\0\0\0"
 
 #define CDIO_EXTENT_BLOCKS(size) ((size + (ISO_BLOCKSIZE - 1)) / ISO_BLOCKSIZE)
 
@@ -506,6 +507,37 @@ struct iso9660_svd_s {
 
 typedef struct iso9660_svd_s  iso9660_svd_t;
 
+/*!
+  \brief ISO-9660 Boot Record Volume Descriptor.
+ */
+struct iso9660_brvd_s {
+    uint8_t          type;                         /**< ISO_VD_BOOT_RECORD - 0 */
+    char             id[5];                        /**< ISO_STANDARD_ID "CD001" */
+    uint8_t          version;                      /**< value 1 for El Torito */
+    char             system_id[ISO_MAX_SYSTEM_ID]; /**< Boot system ID */
+    uint8_t          unused1[32];                  /**< unused - value 0 */
+    uint32_t         boot_catalog_sector;          /**< first sector of boot catalog */
+    uint8_t          unused2[1973];                /**< Unused - value 0 */
+} GNUC_PACKED;
+
+typedef struct iso9660_brvd_s  iso9660_brvd_t;
+
+/*!
+  \brief ISO-9660 Boot Record Volume Descriptor.
+ */
+struct iso9660_br_s {
+    uint8_t          boot_id;                      /**< Boot indicator - 0x88 */
+    uint8_t          media_type;                   /**< Boot media type - 0 for no emul. */
+    uint16_t         load_seg;                     /**< Load segment for x86 */
+    uint8_t          system_type;                  /**< System type - 0 for x86 */
+    uint8_t          unused1;
+    uint16_t         num_sectors;                  /**< Sector count of the image */
+    uint32_t         image_lsn;                    /**< Start address of the image */
+    uint8_t          unused2[20];
+} GNUC_PACKED;
+
+typedef struct iso9660_br_s  iso9660_br_t;
+
 PRAGMA_END_PACKED
 
 /*! \brief A data type for a list of ISO9660
@@ -582,7 +614,8 @@ extern enum iso_extension_enum_s {
   ISO_EXTENSION_JOLIET_LEVEL2 = 0x02,
   ISO_EXTENSION_JOLIET_LEVEL3 = 0x04,
   ISO_EXTENSION_ROCK_RIDGE    = 0x08,
-  ISO_EXTENSION_HIGH_SIERRA   = 0x10
+  ISO_EXTENSION_HIGH_SIERRA   = 0x10,
+  ISO_EXTENSION_EL_TORITO     = 0x20
 } iso_extension_enums;
 
 

src/libcdio/iso9660/iso9660_fs.c

@@ -59,6 +59,8 @@
 #include "_cdio_stdio.h"
 #include "cdio_private.h"
 
+#define MAX_BOOT_IMAGES     8
+
 /** Implementation of iso9660_t type */
 struct _iso9660_s {
   cdio_header_t header;     /**< Internal header - MUST come first. */
@@ -83,6 +85,10 @@ struct _iso9660_s {
 			        be CDIO_CD_FRAMESIZE_RAW (2352) or
 			        M2RAW_SECTOR_SIZE (2336).
                             */
+  struct {
+    uint32_t lsn;	    /**< Start LSN of an El-Torito bootable image */
+    uint32_t num_sectors;   /**< Number of sectors of a bootable image */
+  } boot_img[MAX_BOOT_IMAGES];
   int i_fuzzy_offset;       /**< Adjustment in bytes to make ISO_STANDARD_ID
 			         ("CD001") come out as ISO_PVD_SECTOR
 			         (frame 16).  Normally this should be 0
@@ -505,7 +511,8 @@ iso9660_ifs_read_superblock (iso9660_t *p_iso,
 			     iso_extension_mask_t iso_extension_mask)
 {
   iso9660_svd_t p_svd;  /* Secondary volume descriptor. */
-  int i;
+  iso9660_brvd_t* p_brvd = (iso9660_brvd_t*)&p_svd;  /* Boot record volume descriptor. */
+  int i, j, k;
 
   if (!p_iso || !iso9660_ifs_read_pvd(p_iso, &(p_iso->pvd)))
     return false;
@@ -516,6 +523,24 @@ iso9660_ifs_read_superblock (iso9660_t *p_iso,
   for (i=1; (0 != iso9660_iso_seek_read (p_iso, &p_svd, ISO_PVD_SECTOR+i, 1)); i++) {
     if (ISO_VD_END == from_711(p_svd.type) ) /* Last SVD */
       break;
+    if (iso_extension_mask & ISO_EXTENSION_EL_TORITO) {
+      /* Check for an El-Torito boot volume descriptor */
+      if (ISO_VD_BOOT_RECORD == from_711(p_svd.type) &&
+	  (memcmp(p_brvd->system_id, EL_TORITO_ID, ISO_MAX_SYSTEM_ID) == 0)) {
+	/* Perform very basic parsing of boot entries to fill an image table */
+	iso9660_br_t br[ISO_BLOCKSIZE / sizeof(iso9660_br_t)];
+	if (iso9660_iso_seek_read(p_iso, &br, p_brvd->boot_catalog_sector, 1) == ISO_BLOCKSIZE) {
+	  for (j = 0, k = 0;
+	       j < (ISO_BLOCKSIZE / sizeof(iso9660_br_t)) && k < MAX_BOOT_IMAGES;
+	       j++) {
+	    if (br[j].boot_id == 0x88 && br[j].media_type == 0) {
+	      p_iso->boot_img[k].lsn = br[j].image_lsn;
+	      p_iso->boot_img[k++].num_sectors = br[j].num_sectors;
+	    }
+	  }
+	}
+      }
+    }
     if ( ISO_VD_SUPPLEMENTARY == from_711(p_svd.type) ) {
       /* We're only interested in Joliet => make sure the SVD isn't overwritten */
       if (p_iso->u_joliet_level == 0)
@@ -1441,6 +1466,28 @@ iso9660_fs_stat_translate (CdIo_t *p_cdio, const char psz_path[])
 iso9660_stat_t *
 iso9660_ifs_stat_translate (iso9660_t *p_iso, const char psz_path[])
 {
+  /* Special case for virtual El-Torito boot images ('[BOOT]/#.img') */
+  if (psz_path && (strncmp(psz_path, "[BOOT]/", 7) == 0)) {
+    int index = psz_path[7] - '0';
+    iso9660_stat_t* p_stat;
+    if (strlen(psz_path) < 8)
+      return NULL;
+    if ((psz_path[7] < '0') || (psz_path[7] > '0' + MAX_BOOT_IMAGES - 1))
+      return NULL;
+    if (p_iso->boot_img[index].lsn == 0 || p_iso->boot_img[index].num_sectors == 0)
+      return NULL;
+    p_stat = calloc(1, sizeof(iso9660_stat_t) + strlen(psz_path));
+    if (!p_stat) {
+      cdio_warn("Couldn't calloc(1, %d)", (int)sizeof(iso9660_stat_t));
+      return NULL;
+    }
+    p_stat->lsn = p_iso->boot_img[index].lsn;
+    p_stat->total_size = p_iso->boot_img[index].num_sectors * ISO_BLOCKSIZE;
+    p_stat->type = _STAT_FILE;
+    strcpy(p_stat->filename, psz_path);
+    return p_stat;
+  }
+
   return fs_stat_translate(p_iso, (stat_root_t *) _ifs_stat_root,
 			   (stat_traverse_t *) _fs_iso_stat_traverse,
 			   psz_path);

src/rufus.rc

@@ -33,7 +33,7 @@ LANGUAGE LANG_NEUTRAL, SUBLANG_NEUTRAL
 IDD_DIALOG DIALOGEX 12, 12, 232, 326
 STYLE DS_SETFONT | DS_MODALFRAME | DS_CENTER | WS_MINIMIZEBOX | WS_POPUP | WS_CAPTION | WS_SYSMENU
 EXSTYLE WS_EX_ACCEPTFILES
-CAPTION "Rufus 4.4.2099"
+CAPTION "Rufus 4.4.2100"
 FONT 9, "Segoe UI Symbol", 400, 0, 0x0
 BEGIN
     LTEXT           "Drive Properties",IDS_DRIVE_PROPERTIES_TXT,8,6,53,12,NOT WS_GROUP
@@ -392,8 +392,8 @@ END
 //
 
 VS_VERSION_INFO VERSIONINFO
- FILEVERSION 4,4,2099,0
- PRODUCTVERSION 4,4,2099,0
+ FILEVERSION 4,4,2100,0
+ PRODUCTVERSION 4,4,2100,0
  FILEFLAGSMASK 0x3fL
 #ifdef _DEBUG
  FILEFLAGS 0x1L
@@ -411,13 +411,13 @@ BEGIN
             VALUE "Comments", "https://rufus.ie"
             VALUE "CompanyName", "Akeo Consulting"
             VALUE "FileDescription", "Rufus"
-            VALUE "FileVersion", "4.4.2099"
+            VALUE "FileVersion", "4.4.2100"
             VALUE "InternalName", "Rufus"
             VALUE "LegalCopyright", "� 2011-2024 Pete Batard (GPL v3)"
             VALUE "LegalTrademarks", "https://www.gnu.org/licenses/gpl-3.0.html"
             VALUE "OriginalFilename", "rufus-4.4.exe"
             VALUE "ProductName", "Rufus"
-            VALUE "ProductVersion", "4.4.2099"
+            VALUE "ProductVersion", "4.4.2100"
         END
     END
     BLOCK "VarFileInfo"