lib/zlib_inflate/infutil.c

0001 #include <linux/zutil.h>
0002 #include <linux/errno.h>
0003 #include <linux/slab.h>
0004 #include <linux/vmalloc.h>
0005
0006 /* Utility function: initialize zlib, unpack binary blob, clean up zlib,
0007  * return len or negative error code.
0008  */
0009 int zlib_inflate_blob(void *gunzip_buf, unsigned int sz,
0010               const void *buf, unsigned int len)
0011 {
0012     const u8 *zbuf = buf;
0013     struct z_stream_s *strm;
0014     int rc;
0015
0016     rc = -ENOMEM;
0017     strm = kmalloc(sizeof(*strm), GFP_KERNEL);
0018     if (strm == NULL)
0019         goto gunzip_nomem1;
0020     strm->workspace = kmalloc(zlib_inflate_workspacesize(), GFP_KERNEL);
0021     if (strm->workspace == NULL)
0022         goto gunzip_nomem2;
0023
0024     /* gzip header (1f,8b,08... 10 bytes total + possible asciz filename)
0025      * expected to be stripped from input
0026      */
0027     strm->next_in = zbuf;
0028     strm->avail_in = len;
0029     strm->next_out = gunzip_buf;
0030     strm->avail_out = sz;
0031
0032     rc = zlib_inflateInit2(strm, -MAX_WBITS);
0033     if (rc == Z_OK) {
0034         rc = zlib_inflate(strm, Z_FINISH);
0035         /* after Z_FINISH, only Z_STREAM_END is "we unpacked it all" */
0036         if (rc == Z_STREAM_END)
0037             rc = sz - strm->avail_out;
0038         else
0039             rc = -EINVAL;
0040         zlib_inflateEnd(strm);
0041     } else
0042         rc = -EINVAL;
0043
0044     kfree(strm->workspace);
0045 gunzip_nomem2:
0046     kfree(strm);
0047 gunzip_nomem1:
0048     return rc; /* returns Z_OK (0) if successful */
0049 }