#include <linux/zutil.h>
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#include <linux/errno.h>
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#include <linux/slab.h>
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#include <linux/vmalloc.h>
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/* Utility function: initialize zlib, unpack binary blob, clean up zlib,
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* return len or negative error code.
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*/
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int zlib_inflate_blob(void *gunzip_buf, unsigned int sz,
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const void *buf, unsigned int len)
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{
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const u8 *zbuf = buf;
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struct z_stream_s *strm;
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int rc;
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rc = -ENOMEM;
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strm = kmalloc(sizeof(*strm), GFP_KERNEL);
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if (strm == NULL)
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goto gunzip_nomem1;
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strm->workspace = kmalloc(zlib_inflate_workspacesize(), GFP_KERNEL);
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if (strm->workspace == NULL)
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goto gunzip_nomem2;
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/* gzip header (1f,8b,08... 10 bytes total + possible asciz filename)
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* expected to be stripped from input
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*/
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strm->next_in = zbuf;
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strm->avail_in = len;
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strm->next_out = gunzip_buf;
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strm->avail_out = sz;
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rc = zlib_inflateInit2(strm, -MAX_WBITS);
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if (rc == Z_OK) {
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rc = zlib_inflate(strm, Z_FINISH);
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/* after Z_FINISH, only Z_STREAM_END is "we unpacked it all" */
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if (rc == Z_STREAM_END)
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rc = sz - strm->avail_out;
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else
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rc = -EINVAL;
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zlib_inflateEnd(strm);
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} else
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rc = -EINVAL;
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kfree(strm->workspace);
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gunzip_nomem2:
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kfree(strm);
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gunzip_nomem1:
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return rc; /* returns Z_OK (0) if successful */
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}
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