arch/xtensa/boot/lib/zmem.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/zlib.h>
   3
   4 /* bits taken from ppc */
   5
   6 extern void *avail_ram, *end_avail;
   7 void gunzip(void *dst, int dstlen, unsigned char *src, int *lenp);
   8
   9 static void exit(void)
  10 {
  11   for (;;);
  12 }
  13
  14 static void *zalloc(unsigned int size)
  15 {
  16         void *p = avail_ram;
  17
  18         size = (size + 7) & -8;
  19         avail_ram += size;
  20         if (avail_ram > end_avail) {
  21                 //puts("oops... out of memory\n");
  22                 //pause();
  23                 exit ();
  24         }
  25         return p;
  26 }
  27
  28 #define HEAD_CRC        2
  29 #define EXTRA_FIELD     4
  30 #define ORIG_NAME       8
  31 #define COMMENT         0x10
  32 #define RESERVED        0xe0
  33
  34 #define DEFLATED        8
  35
  36 void gunzip (void *dst, int dstlen, unsigned char *src, int *lenp)
  37 {
  38         z_stream s;
  39         int r, i, flags;
  40
  41         /* skip header */
  42         i = 10;
  43         flags = src[3];
  44         if (src[2] != DEFLATED || (flags & RESERVED) != 0) {
  45                 //puts("bad gzipped data\n");
  46                 exit();
  47         }
  48         if ((flags & EXTRA_FIELD) != 0)
  49                 i = 12 + src[10] + (src[11] << 8);
  50         if ((flags & ORIG_NAME) != 0)
  51                 while (src[i++] != 0)
  52                         ;
  53         if ((flags & COMMENT) != 0)
  54                 while (src[i++] != 0)
  55                         ;
  56         if ((flags & HEAD_CRC) != 0)
  57                 i += 2;
  58         if (i >= *lenp) {
  59                 //puts("gunzip: ran out of data in header\n");
  60                 exit();
  61         }
  62
  63         s.workspace = zalloc(zlib_inflate_workspacesize());
  64         r = zlib_inflateInit2(&s, -MAX_WBITS);
  65         if (r != Z_OK) {
  66                 //puts("inflateInit2 returned "); puthex(r); puts("\n");
  67                 exit();
  68         }
  69         s.next_in = src + i;
  70         s.avail_in = *lenp - i;
  71         s.next_out = dst;
  72         s.avail_out = dstlen;
  73         r = zlib_inflate(&s, Z_FINISH);
  74         if (r != Z_OK && r != Z_STREAM_END) {
  75                 //puts("inflate returned "); puthex(r); puts("\n");
  76                 exit();
  77         }
  78         *lenp = s.next_out - (unsigned char *) dst;
  79         zlib_inflateEnd(&s);
  80 }
  81