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    • /[magellan-source]/trunk/mkinitrd-magellan/busybox/util-linux/volume_id/util.c

    Diff of /trunk/mkinitrd-magellan/busybox/util-linux/volume_id/util.c

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    revision 983 by niro, Fri Apr 24 18:33:46 2009 UTC revision 984 by niro, Sun May 30 11:32:42 2010 UTC
    # Line 195  set: Line 195  set:
    195   * It's better to ignore such fs and continue.  */   * It's better to ignore such fs and continue.  */
    196  void *volume_id_get_buffer(struct volume_id *id, uint64_t off, size_t len)  void *volume_id_get_buffer(struct volume_id *id, uint64_t off, size_t len)
    197  {  {
    198   ssize_t buf_len;   uint8_t *dst;
    199     unsigned small_off;
    200     ssize_t read_len;
    201    
    202     dbg("get buffer off 0x%llx(%llu), len 0x%zx",
    203     (unsigned long long) off, (unsigned long long) off, len);
    204    
      dbg("get buffer off 0x%llx(%llu), len 0x%zx", (unsigned long long) off, (unsigned long long) off, len);  
    205   /* check if requested area fits in superblock buffer */   /* check if requested area fits in superblock buffer */
    206   if (off + len <= SB_BUFFER_SIZE) {   if (off + len <= SB_BUFFER_SIZE
    207     /* && off <= SB_BUFFER_SIZE - want this paranoid overflow check? */
    208     ) {
    209   if (id->sbbuf == NULL) {   if (id->sbbuf == NULL) {
    210   id->sbbuf = xmalloc(SB_BUFFER_SIZE);   id->sbbuf = xmalloc(SB_BUFFER_SIZE);
    211   }   }
    212     small_off = off;
    213     dst = id->sbbuf;
    214    
    215   /* check if we need to read */   /* check if we need to read */
    216   if ((off + len) > id->sbbuf_len) {   len += off;
    217   dbg("read sbbuf len:0x%llx", (unsigned long long) (off + len));   if (len <= id->sbbuf_len)
    218   if (lseek(id->fd, 0, SEEK_SET) != 0) {   goto ret; /* we already have it */
    219   dbg("seek(0) failed");  
    220   return NULL;   dbg("read sbbuf len:0x%x", (unsigned) len);
    221   }   id->sbbuf_len = len;
    222   buf_len = full_read(id->fd, id->sbbuf, off + len);   off = 0;
    223   if (buf_len < 0) {   goto do_read;
      dbg("read failed (%s)", strerror(errno));  
      return NULL;  
      }  
      dbg("got 0x%zx (%zi) bytes", buf_len, buf_len);  
      id->sbbuf_len = buf_len;  
      if ((uint64_t)buf_len < off + len) {  
      dbg("requested 0x%zx bytes, got only 0x%zx bytes", len, buf_len);  
      return NULL;  
      }  
      }  
       
      return &(id->sbbuf[off]);  
    224   }   }
    225    
    226   if (len > SEEK_BUFFER_SIZE) {   if (len > SEEK_BUFFER_SIZE) {
    227   dbg("seek buffer too small %d", SEEK_BUFFER_SIZE);   dbg("seek buffer too small %d", SEEK_BUFFER_SIZE);
    228   return NULL;   return NULL;
    229   }   }
    230     dst = id->seekbuf;
      /* get seek buffer */  
      if (id->seekbuf == NULL) {  
      id->seekbuf = xmalloc(SEEK_BUFFER_SIZE);  
      }  
    231    
    232   /* check if we need to read */   /* check if we need to read */
    233   if ((off < id->seekbuf_off) || ((off + len) > (id->seekbuf_off + id->seekbuf_len))) {   if ((off >= id->seekbuf_off)
    234   dbg("read seekbuf off:0x%llx len:0x%zx", (unsigned long long) off, len);   && ((off + len) <= (id->seekbuf_off + id->seekbuf_len))
    235   if (lseek(id->fd, off, SEEK_SET) != off) {   ) {
    236   dbg("seek(0x%llx) failed", (unsigned long long) off);   small_off = off - id->seekbuf_off; /* can't overflow */
    237   return NULL;   goto ret; /* we already have it */
      }  
      buf_len = full_read(id->fd, id->seekbuf, len);  
      if (buf_len < 0) {  
      dbg("read failed (%s)", strerror(errno));  
      return NULL;  
      }  
      dbg("got 0x%zx (%zi) bytes", buf_len, buf_len);  
      id->seekbuf_off = off;  
      id->seekbuf_len = buf_len;  
      if ((size_t)buf_len < len) {  
      dbg("requested 0x%zx bytes, got only 0x%zx bytes", len, buf_len);  
      return NULL;  
      }  
    238   }   }
    239    
    240   return &(id->seekbuf[off - id->seekbuf_off]);   id->seekbuf_off = off;
    241     id->seekbuf_len = len;
    242     id->seekbuf = xrealloc(id->seekbuf, len);
    243     small_off = 0;
    244     dst = id->seekbuf;
    245     dbg("read seekbuf off:0x%llx len:0x%zx",
    246     (unsigned long long) off, len);
    247     do_read:
    248     if (lseek(id->fd, off, SEEK_SET) != off) {
    249     dbg("seek(0x%llx) failed", (unsigned long long) off);
    250     goto err;
    251     }
    252     read_len = full_read(id->fd, dst, len);
    253     if (read_len != len) {
    254     dbg("requested 0x%x bytes, got 0x%x bytes",
    255     (unsigned) len, (unsigned) read_len);
    256     err:
    257     /* No filesystem can be this tiny. It's most likely
    258     * non-associated loop device, empty drive and so on.
    259     * Flag it, making it possible to short circuit future
    260     * accesses. Rationale:
    261     * users complained of slow blkid due to empty floppy drives.
    262     */
    263     if (off < 64*1024)
    264     id->error = 1;
    265     /* id->seekbuf_len or id->sbbuf_len is wrong now! Fixing. */
    266     volume_id_free_buffer(id);
    267     return NULL;
    268     }
    269     ret:
    270     return dst + small_off;
    271  }  }
    272    
    273  void volume_id_free_buffer(struct volume_id *id)  void volume_id_free_buffer(struct volume_id *id)
    # Line 269  void volume_id_free_buffer(struct volume Line 278  void volume_id_free_buffer(struct volume
    278   free(id->seekbuf);   free(id->seekbuf);
    279   id->seekbuf = NULL;   id->seekbuf = NULL;
    280   id->seekbuf_len = 0;   id->seekbuf_len = 0;
    281     id->seekbuf_off = 0; /* paranoia */
    282  }  }
    Legend:
    Removed from v.983  
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      Added in v.984