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 INIT 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)(char *x)) {
  42         u8 *zbuf;
  43         struct z_stream_s *strm;
  44         int rc;
  45         size_t out_len;
  46
  47         rc = -1;
  48         if (flush) {
  49                 out_len = 0x8000; /* 32 K */
  50                 out_buf = malloc(out_len);
  51         } else {
  52                 out_len = 0x7fffffff; /* no limit */
  53         }
  54         if (!out_buf) {
  55                 error("Out of memory while allocating output buffer");
  56                 goto gunzip_nomem1;
  57         }
  58
  59         if (buf)
  60                 zbuf = buf;
  61         else {
  62                 zbuf = malloc(GZIP_IOBUF_SIZE);
  63                 len = 0;
  64         }
  65         if (!zbuf) {
  66                 error("Out of memory while allocating input buffer");
  67                 goto gunzip_nomem2;
  68         }
  69
  70         strm = malloc(sizeof(*strm));
  71         if (strm == NULL) {
  72                 error("Out of memory while allocating z_stream");
  73                 goto gunzip_nomem3;
  74         }
  75
  76         strm->workspace = malloc(flush ? zlib_inflate_workspacesize() :
  77                                  sizeof(struct inflate_state));
  78         if (strm->workspace == NULL) {
  79                 error("Out of memory while allocating workspace");
  80                 goto gunzip_nomem4;
  81         }
  82
  83         if (!fill)
  84                 fill = nofill;
  85
  86         if (len == 0)
  87                 len = fill(zbuf, GZIP_IOBUF_SIZE);
  88
  89         /* verify the gzip header */
  90         if (len < 10 ||
  91            zbuf[0] != 0x1f || zbuf[1] != 0x8b || zbuf[2] != 0x08) {
  92                 if (pos)
  93                         *pos = 0;
  94                 error("Not a gzip file");
  95                 goto gunzip_5;
  96         }
  97
  98         /* skip over gzip header (1f,8b,08... 10 bytes total +
  99          * possible asciz filename)
 100          */
 101         strm->next_in = zbuf + 10;
 102         /* skip over asciz filename */
 103         if (zbuf[3] & 0x8) {
 104                 while (strm->next_in[0])
 105                         strm->next_in++;
 106                 strm->next_in++;
 107         }
 108         strm->avail_in = len - (strm->next_in - zbuf);
 109
 110         strm->next_out = out_buf;
 111         strm->avail_out = out_len;
 112
 113         rc = zlib_inflateInit2(strm, -MAX_WBITS);
 114
 115         if (!flush) {
 116                 WS(strm)->inflate_state.wsize = 0;
 117                 WS(strm)->inflate_state.window = NULL;
 118         }
 119
 120         while (rc == Z_OK) {
 121                 if (strm->avail_in == 0) {
 122                         /* TODO: handle case where both pos and fill are set */
 123                         len = fill(zbuf, GZIP_IOBUF_SIZE);
 124                         if (len < 0) {
 125                                 rc = -1;
 126                                 error("read error");
 127                                 break;
 128                         }
 129                         strm->next_in = zbuf;
 130                         strm->avail_in = len;
 131                 }
 132                 rc = zlib_inflate(strm, 0);
 133
 134                 /* Write any data generated */
 135                 if (flush && strm->next_out > out_buf) {
 136                         int l = strm->next_out - out_buf;
 137                         if (l != flush(out_buf, l)) {
 138                                 rc = -1;
 139                                 error("write error");
 140                                 break;
 141                         }
 142                         strm->next_out = out_buf;
 143                         strm->avail_out = out_len;
 144                 }
 145
 146                 /* after Z_FINISH, only Z_STREAM_END is "we unpacked it all" */
 147                 if (rc == Z_STREAM_END) {
 148                         rc = 0;
 149                         break;
 150                 } else if (rc != Z_OK) {
 151                         error("uncompression error");
 152                         rc = -1;
 153                 }
 154         }
 155
 156         zlib_inflateEnd(strm);
 157         if (pos)
 158                 /* add + 8 to skip over trailer */
 159                 *pos = strm->next_in - zbuf+8;
 160
 161 gunzip_5:
 162         free(strm->workspace);
 163 gunzip_nomem4:
 164         free(strm);
 165 gunzip_nomem3:
 166         if (!buf)
 167                 free(zbuf);
 168 gunzip_nomem2:
 169         if (flush)
 170                 free(out_buf);
 171 gunzip_nomem1:
 172         return rc; /* returns Z_OK (0) if successful */
 173 }
 174
 175 #define decompress gunzip