sys/src/boot/efi/iso.c

   1 #include <u.h>
   2 #include "fns.h"
   3 #include "efi.h"
   4
   5 enum {
   6         Sectsz = 0x800,
   7         Dirsz = 33,
   8 };
   9
  10 typedef struct Extend Extend;
  11 typedef struct Dir Dir;
  12
  13 struct Extend
  14 {
  15         ulong lba;
  16         ulong len;
  17         uchar *rp;
  18         uchar *ep;
  19         uchar buf[Sectsz];
  20 };
  21
  22 struct Dir
  23 {
  24         uchar dirlen;
  25         uchar extlen;
  26
  27         uchar lba[8];
  28         uchar len[8];
  29
  30         uchar date[7];
  31
  32         uchar flags[3];
  33
  34         uchar seq[4];
  35
  36         uchar namelen;
  37 };
  38
  39 typedef struct {
  40         UINT32          MediaId;
  41
  42         BOOLEAN         RemovableMedia;
  43         BOOLEAN         MediaPresent;
  44         BOOLEAN         LogicalPartition;
  45         BOOLEAN         ReadOnly;
  46
  47         BOOLEAN         WriteCaching;
  48         BOOLEAN         Pad[3];
  49
  50         UINT32          BlockSize;
  51         UINT32          IoAlign;
  52         UINT64          LastBlock;
  53 } EFI_BLOCK_IO_MEDIA;
  54
  55 typedef struct {
  56         UINT64          Revision;
  57         EFI_BLOCK_IO_MEDIA      *Media;
  58         void            *Reset;
  59         void            *ReadBlocks;
  60         void            *WriteBlocks;
  61         void            *FlushBlocks;
  62 } EFI_BLOCK_IO_PROTOCOL;
  63
  64 static EFI_GUID
  65 EFI_BLOCK_IO_PROTOCO_GUID = {
  66         0x964e5b21, 0x6459, 0x11d2,
  67         0x8e, 0x39, 0x00, 0xa0,
  68         0xc9, 0x69, 0x72, 0x3b,
  69 };
  70
  71 static EFI_BLOCK_IO_PROTOCOL *bio;
  72
  73 static int
  74 readsect(ulong lba, void *buf)
  75 {
  76         lba *= Sectsz/bio->Media->BlockSize;
  77         return eficall(bio->ReadBlocks, bio, (UINTN)bio->Media->MediaId, (UINT64)lba, (UINTN)Sectsz, buf);
  78 }
  79
  80 static int
  81 isoread(void *f, void *data, int len)
  82 {
  83         Extend *ex = f;
  84
  85         if(ex->len > 0 && ex->rp >= ex->ep)
  86                 if(readsect(ex->lba++, ex->rp = ex->buf))
  87                         return -1;
  88         if(ex->len < len)
  89                 len = ex->len;
  90         if(len > (ex->ep - ex->rp))
  91                 len = ex->ep - ex->rp;
  92         memmove(data, ex->rp, len);
  93         ex->rp += len;
  94         ex->len -= len;
  95         return len;
  96 }
  97
  98 void
  99 isoclose(void *f)
 100 {
 101         Extend *ex = f;
 102
 103         ex->lba = 0;
 104         ex->len = 0;
 105         ex->rp = ex->ep = ex->buf + Sectsz;
 106 }
 107
 108 static int
 109 isowalk(Extend *ex, char *path)
 110 {
 111         char name[MAXPATH], c, *end;
 112         int i;
 113         Dir d;
 114
 115         isoclose(ex);
 116
 117         /* find pvd */
 118         for(i=0x10; i<0x1000; i++){
 119                 if(readsect(i, ex->buf))
 120                         return -1;
 121                 if(memcmp(ex->buf, "\001CD001\001", 7) == 0)
 122                         goto Foundpvd;
 123         }
 124         return -1;
 125 Foundpvd:
 126         ex->lba = *((ulong*)(ex->buf + 156 + 2));
 127         ex->len = *((ulong*)(ex->buf + 156 + 10));
 128         if(*path == 0)
 129                 return 0;
 130
 131         for(;;){
 132                 if(readn(ex, &d, Dirsz) != Dirsz)
 133                         break;
 134                 if(d.dirlen == 0)
 135                         break;
 136                 if(readn(ex, name, d.namelen) != d.namelen)
 137                         break;
 138                 i = d.dirlen - (Dirsz + d.namelen);
 139                 while(i-- > 0)
 140                         read(ex, &c, 1);
 141                 for(i=0; i<d.namelen; i++){
 142                         c = name[i];
 143                         if(c >= 'A' && c <= 'Z'){
 144                                 c -= 'A';
 145                                 c += 'a';
 146                         }
 147                         name[i] = c;
 148                 }
 149                 name[i] = 0;
 150                 while(*path == '/')
 151                         path++;
 152                 if((end = strchr(path, '/')) == 0)
 153                         end = path + strlen(path);
 154                 i = end - path;
 155                 if(d.namelen == i && memcmp(name, path, i) == 0){
 156                         ex->rp = ex->ep;
 157                         ex->lba = *((ulong*)d.lba);
 158                         ex->len = *((ulong*)d.len);
 159                         if(*end == 0)
 160                                 return 0;
 161                         else if(d.flags[0] & 2){
 162                                 path = end;
 163                                 continue;
 164                         }
 165                         break;
 166                 }
 167         }
 168         return -1;
 169 }
 170
 171 static void*
 172 isoopen(char *path)
 173 {
 174         static uchar buf[sizeof(Extend)+8];
 175         Extend *ex = (Extend*)((uintptr)(buf+7)&~7);
 176
 177         if(isowalk(ex, path))
 178                 return nil;
 179         return ex;
 180 }
 181
 182 int
 183 isoinit(void **fp)
 184 {
 185         EFI_BLOCK_IO_MEDIA *media;
 186         EFI_HANDLE *Handles;
 187         UINTN Count;
 188         int i;
 189
 190         bio = nil;
 191         Count = 0;
 192         Handles = nil;
 193         if(eficall(ST->BootServices->LocateHandleBuffer,
 194                 ByProtocol, &EFI_BLOCK_IO_PROTOCO_GUID, nil, &Count, &Handles))
 195                 return -1;
 196
 197         for(i=0; i<Count; i++){
 198                 bio = nil;
 199                 if(eficall(ST->BootServices->HandleProtocol,
 200                         Handles[i], &EFI_BLOCK_IO_PROTOCO_GUID, &bio))
 201                         continue;
 202
 203                 media = bio->Media;
 204                 if(media != nil
 205                 && media->MediaPresent
 206                 && media->LogicalPartition == 0
 207                 && media->BlockSize != 0
 208                 && isoopen("") != nil)
 209                         goto Found;
 210         }
 211         return -1;
 212
 213 Found:
 214         open = isoopen;
 215         read = isoread;
 216         close = isoclose;
 217
 218         if(fp != nil)
 219                 *fp = isoopen("/cfg/plan9.ini");
 220
 221         return 0;
 222 }