lib/decompress_inflate.c

   1 #ifdef STATIC
   2 /* Pre-boot environment: included */
   3
   4 /* prevent inclusion of _LINUX_KERNEL_H in pre-boot environment: lots
   5  * errors about console_printk etc... on ARM */
   6 #define _LINUX_KERNEL_H
   7
   8 #include "zlib_inflate/inftrees.c"
   9 #include "zlib_inflate/inffast.c"
  10 #include "zlib_inflate/inflate.c"
  11
  12 #else /* STATIC */
  13 /* initramfs et al: linked */
  14
  15 #include <linux/zutil.h>
  16
  17 #include "zlib_inflate/inftrees.h"
  18 #include "zlib_inflate/inffast.h"
  19 #include "zlib_inflate/inflate.h"
  20
  21 #include "zlib_inflate/infutil.h"
  22 #include <linux/slab.h>
  23
  24 #endif /* STATIC */
  25
  26 #include <linux/decompress/mm.h>
  27
  28 #define GZIP_IOBUF_SIZE (16*1024)
  29
  30 static int nofill(void *buffer, unsigned int len)
  31 {
  32         return -1;
  33 }
  34
  35 /* Included from initramfs et al code */
  36 STATIC int INIT gunzip(unsigned char *buf, int len,
  37                        int(*fill)(void*, unsigned int),
  38                        int(*flush)(void*, unsigned int),
  39                        unsigned char *out_buf,
  40                        int *pos,
  41                        void(*error_fn)(char *x)) {
  42         u8 *zbuf;
  43         struct z_stream_s *strm;
  44         int rc;
  45         size_t out_len;
  46
  47         set_error_fn(error_fn);
  48         rc = -1;
  49         if (flush) {
  50                 out_len = 0x8000; /* 32 K */
  51                 out_buf = malloc(out_len);
  52         } else {
  53                 out_len = 0x7fffffff; /* no limit */
  54         }
  55         if (!out_buf) {
  56                 error("Out of memory while allocating output buffer");
  57                 goto gunzip_nomem1;
  58         }
  59
  60         if (buf)
  61                 zbuf = buf;
  62         else {
  63                 zbuf = malloc(GZIP_IOBUF_SIZE);
  64                 len = 0;
  65         }
  66         if (!zbuf) {
  67                 error("Out of memory while allocating input buffer");
  68                 goto gunzip_nomem2;
  69         }
  70
  71         strm = malloc(sizeof(*strm));
  72         if (strm == NULL) {
  73                 error("Out of memory while allocating z_stream");
  74                 goto gunzip_nomem3;
  75         }
  76
  77         strm->workspace = malloc(flush ? zlib_inflate_workspacesize() :
  78                                  sizeof(struct inflate_state));
  79         if (strm->workspace == NULL) {
  80                 error("Out of memory while allocating workspace");
  81                 goto gunzip_nomem4;
  82         }
  83
  84         if (!fill)
  85                 fill = nofill;
  86
  87         if (len == 0)
  88                 len = fill(zbuf, GZIP_IOBUF_SIZE);
  89
  90         /* verify the gzip header */
  91         if (len < 10 ||
  92            zbuf[0] != 0x1f || zbuf[1] != 0x8b || zbuf[2] != 0x08) {
  93                 if (pos)
  94                         *pos = 0;
  95                 error("Not a gzip file");
  96                 goto gunzip_5;
  97         }
  98
  99         /* skip over gzip header (1f,8b,08... 10 bytes total +
 100          * possible asciz filename)
 101          */
 102         strm->next_in = zbuf + 10;
 103         /* skip over asciz filename */
 104         if (zbuf[3] & 0x8) {
 105                 while (strm->next_in[0])
 106                         strm->next_in++;
 107                 strm->next_in++;
 108         }
 109         strm->avail_in = len - (strm->next_in - zbuf);
 110
 111         strm->next_out = out_buf;
 112         strm->avail_out = out_len;
 113
 114         rc = zlib_inflateInit2(strm, -MAX_WBITS);
 115
 116         if (!flush) {
 117                 WS(strm)->inflate_state.wsize = 0;
 118                 WS(strm)->inflate_state.window = NULL;
 119         }
 120
 121         while (rc == Z_OK) {
 122                 if (strm->avail_in == 0) {
 123                         /* TODO: handle case where both pos and fill are set */
 124                         len = fill(zbuf, GZIP_IOBUF_SIZE);
 125                         if (len < 0) {
 126                                 rc = -1;
 127                                 error("read error");
 128                                 break;
 129                         }
 130                         strm->next_in = zbuf;
 131                         strm->avail_in = len;
 132                 }
 133                 rc = zlib_inflate(strm, 0);
 134
 135                 /* Write any data generated */
 136                 if (flush && strm->next_out > out_buf) {
 137                         int l = strm->next_out - out_buf;
 138                         if (l != flush(out_buf, l)) {
 139                                 rc = -1;
 140                                 error("write error");
 141                                 break;
 142                         }
 143                         strm->next_out = out_buf;
 144                         strm->avail_out = out_len;
 145                 }
 146
 147                 /* after Z_FINISH, only Z_STREAM_END is "we unpacked it all" */
 148                 if (rc == Z_STREAM_END) {
 149                         rc = 0;
 150                         break;
 151                 } else if (rc != Z_OK) {
 152                         error("uncompression error");
 153                         rc = -1;
 154                 }
 155         }
 156
 157         zlib_inflateEnd(strm);
 158         if (pos)
 159                 /* add + 8 to skip over trailer */
 160                 *pos = strm->next_in - zbuf+8;
 161
 162 gunzip_5:
 163         free(strm->workspace);
 164 gunzip_nomem4:
 165         free(strm);
 166 gunzip_nomem3:
 167         if (!buf)
 168                 free(zbuf);
 169 gunzip_nomem2:
 170         if (flush)
 171                 free(out_buf);
 172 gunzip_nomem1:
 173         return rc; /* returns Z_OK (0) if successful */
 174 }
 175
 176 #define decompress gunzip