minix/fs/isofs/susp.c

   1 /*
   2  * This file contains support for System Use Sharing Protocol (SUSP) extension
   3  * to ISO 9660.
   4  */
   5
   6 #include "inc.h"
   7 #include <sys/stat.h>
   8
   9 #ifdef ISO9660_OPTION_ROCKRIDGE
  10
  11 int parse_susp(struct rrii_dir_record *dir, char *buffer)
  12 {
  13         /* Parse fundamental SUSP entries */
  14         char susp_signature[2];
  15         u8_t susp_length;
  16         u8_t susp_version;
  17         u32_t ca_block_nr;
  18         u32_t ca_offset;
  19         u32_t ca_length;
  20         struct buf *ca_bp;
  21         int r;
  22
  23         susp_signature[0] = buffer[0];
  24         susp_signature[1] = buffer[1];
  25         susp_length = *((u8_t*)buffer + 2);
  26         susp_version = *((u8_t*)buffer + 3);
  27
  28         if ((susp_signature[0] == 'C') && (susp_signature[1] == 'E') &&
  29             (susp_length >= 28) && (susp_version >= 1)) {
  30                 /*
  31                  * Continuation area, perform a recursion.
  32                  *
  33                  * FIXME: Currently we're parsing only first logical block of a
  34                  * continuation area, and infinite recursion is not checked.
  35                  */
  36
  37                 ca_block_nr = *((u32_t*)(buffer + 4));
  38                 ca_offset = *((u32_t*)(buffer + 12));
  39                 ca_length = *((u32_t*)(buffer + 20));
  40
  41                 /* Truncate continuation area to fit one logical block. */
  42                 if (ca_offset >= v_pri.logical_block_size_l) {
  43                         return EINVAL;
  44                 }
  45                 if (ca_offset + ca_length > v_pri.logical_block_size_l) {
  46                         ca_length = v_pri.logical_block_size_l - ca_offset;
  47                 }
  48
  49                 r = lmfs_get_block(&ca_bp, fs_dev, ca_block_nr, NORMAL);
  50                 if (r != OK)
  51                         return r;
  52
  53                 parse_susp_buffer(dir, b_data(ca_bp) + ca_offset, ca_length);
  54                 lmfs_put_block(ca_bp);
  55
  56                 return OK;
  57         }
  58         else if ((susp_signature[0] == 'P') && (susp_signature[1] == 'D')) {
  59                 /* Padding, skip. */
  60                 return OK;
  61         }
  62         else if ((susp_signature[0] == 'S') && (susp_signature[1] == 'P')) {
  63                 /* Ignored, skip. */
  64                 return OK;
  65         }
  66         else if ((susp_signature[0] == 'S') && (susp_signature[1] == 'T')) {
  67                 /* Terminator entry, stop processing. */
  68                 return(ECANCELED);
  69         }
  70         else if ((susp_signature[0] == 'E') && (susp_signature[1] == 'R')) {
  71                 /* Ignored, skip. */
  72                 return OK;
  73         }
  74         else if ((susp_signature[0] == 'E') && (susp_signature[1] == 'S')) {
  75                 /* Ignored, skip. */
  76                 return OK;
  77         }
  78
  79         /* Not a SUSP fundamental entry. */
  80         return EINVAL;
  81 }
  82
  83 void parse_susp_buffer(struct rrii_dir_record *dir, char *buffer, u32_t size)
  84 {
  85         /*
  86          * Parse a SUSP system use entry for the ISO 9660.
  87          * This is the main entry point for parsing SUSP data : SUSP entries are
  88          * routed from here to the relevant handling functions.
  89          */
  90         char susp_signature[2];
  91         u8_t susp_length;
  92
  93         int parser_return;
  94
  95         while (TRUE) {
  96                 /* A SUSP entry can't be smaller than 4 bytes. */
  97                 if (size < 4)
  98                         return;
  99
 100                 susp_signature[0] = buffer[0];
 101                 susp_signature[1] = buffer[1];
 102                 susp_length = *((u8_t*)buffer + 2);
 103
 104                 /* Check if SUSP entry is present. */
 105                 if (((susp_signature[0] == 0) && (susp_signature[1] == 0)) ||
 106                     (susp_length > size) || (susp_length < 4))
 107                         return;
 108
 109                 /* Check for SUSP fundamental entry. */
 110                 parser_return = parse_susp(dir, buffer);
 111                 if (parser_return == ECANCELED)
 112                         return;
 113                 else if (parser_return == OK)
 114                         goto next_entry;
 115
 116                 /* Check for Rock Ridge entry. */
 117                 if (opt.norock == FALSE) {
 118                         parser_return = parse_susp_rock_ridge(dir, buffer);
 119                         if (parser_return == ECANCELED)
 120                                 return;
 121                         else if (parser_return == OK)
 122                                 goto next_entry;
 123                 }
 124
 125                 /* Parse next SUSP entry. */
 126         next_entry:
 127                 buffer += susp_length;
 128                 size -= susp_length;
 129         }
 130 }
 131
 132 #endif