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