fs/jffs2/compr_zlib.c

   1 /*
   2  * JFFS2 -- Journalling Flash File System, Version 2.
   3  *
   4  * Copyright (C) 2001-2003 Red Hat, Inc.
   5  *
   6  * Created by David Woodhouse <dwmw2@redhat.com>
   7  *
   8  * For licensing information, see the file 'LICENCE' in this directory.
   9  *
  10  * $Id: compr_zlib.c,v 1.24 2003/10/04 08:33:06 dwmw2 Exp $
  11  *
  12  */
  13
  14 #if !defined(__KERNEL__) && !defined(__ECOS)
  15 #error "The userspace support got too messy and was removed. Update your mkfs.jffs2"
  16 #endif
  17
  18 #include <linux/config.h>
  19 #include <linux/kernel.h>
  20 #include <linux/vmalloc.h>
  21 #include <linux/init.h>
  22 #include <linux/slab.h>
  23 #include <linux/zlib.h>
  24 #include <linux/zutil.h>
  25 #include <asm/semaphore.h>
  26 #include "nodelist.h"
  27
  28         /* Plan: call deflate() with avail_in == *sourcelen,
  29                 avail_out = *dstlen - 12 and flush == Z_FINISH.
  30                 If it doesn't manage to finish, call it again with
  31                 avail_in == 0 and avail_out set to the remaining 12
  32                 bytes for it to clean up.
  33            Q: Is 12 bytes sufficient?
  34         */
  35 #define STREAM_END_SPACE 12
  36
  37 static DECLARE_MUTEX(deflate_sem);
  38 static DECLARE_MUTEX(inflate_sem);
  39 static z_stream inf_strm, def_strm;
  40
  41 #ifdef __KERNEL__ /* Linux-only */
  42 int __init jffs2_zlib_init(void)
  43 {
  44         def_strm.workspace = vmalloc(zlib_deflate_workspacesize());
  45         if (!def_strm.workspace) {
  46                 printk(KERN_WARNING "Failed to allocate %d bytes for deflate workspace\n", zlib_deflate_workspacesize());
  47                 return -ENOMEM;
  48         }
  49         D1(printk(KERN_DEBUG "Allocated %d bytes for deflate workspace\n", zlib_deflate_workspacesize()));
  50         inf_strm.workspace = vmalloc(zlib_inflate_workspacesize());
  51         if (!inf_strm.workspace) {
  52                 printk(KERN_WARNING "Failed to allocate %d bytes for inflate workspace\n", zlib_inflate_workspacesize());
  53                 vfree(def_strm.workspace);
  54                 return -ENOMEM;
  55         }
  56         D1(printk(KERN_DEBUG "Allocated %d bytes for inflate workspace\n", zlib_inflate_workspacesize()));
  57         return 0;
  58 }
  59
  60 void jffs2_zlib_exit(void)
  61 {
  62         vfree(def_strm.workspace);
  63         vfree(inf_strm.workspace);
  64 }
  65 #endif /* __KERNEL__ */
  66
  67 int jffs2_zlib_compress(unsigned char *data_in, unsigned char *cpage_out,
  68                    uint32_t *sourcelen, uint32_t *dstlen)
  69 {
  70         int ret;
  71
  72         if (*dstlen <= STREAM_END_SPACE)
  73                 return -1;
  74
  75         down(&deflate_sem);
  76
  77         if (Z_OK != zlib_deflateInit(&def_strm, 3)) {
  78                 printk(KERN_WARNING "deflateInit failed\n");
  79                 up(&deflate_sem);
  80                 return -1;
  81         }
  82
  83         def_strm.next_in = data_in;
  84         def_strm.total_in = 0;
  85
  86         def_strm.next_out = cpage_out;
  87         def_strm.total_out = 0;
  88
  89         while (def_strm.total_out < *dstlen - STREAM_END_SPACE && def_strm.total_in < *sourcelen) {
  90                 def_strm.avail_out = *dstlen - (def_strm.total_out + STREAM_END_SPACE);
  91                 def_strm.avail_in = min((unsigned)(*sourcelen-def_strm.total_in), def_strm.avail_out);
  92                 D1(printk(KERN_DEBUG "calling deflate with avail_in %d, avail_out %d\n",
  93                           def_strm.avail_in, def_strm.avail_out));
  94                 ret = zlib_deflate(&def_strm, Z_PARTIAL_FLUSH);
  95                 D1(printk(KERN_DEBUG "deflate returned with avail_in %d, avail_out %d, total_in %ld, total_out %ld\n",
  96                           def_strm.avail_in, def_strm.avail_out, def_strm.total_in, def_strm.total_out));
  97                 if (ret != Z_OK) {
  98                         D1(printk(KERN_DEBUG "deflate in loop returned %d\n", ret));
  99                         zlib_deflateEnd(&def_strm);
 100                         up(&deflate_sem);
 101                         return -1;
 102                 }
 103         }
 104         def_strm.avail_out += STREAM_END_SPACE;
 105         def_strm.avail_in = 0;
 106         ret = zlib_deflate(&def_strm, Z_FINISH);
 107         zlib_deflateEnd(&def_strm);
 108
 109         if (ret != Z_STREAM_END) {
 110                 D1(printk(KERN_DEBUG "final deflate returned %d\n", ret));
 111                 ret = -1;
 112                 goto out;
 113         }
 114
 115         if (def_strm.total_out >= def_strm.total_in) {
 116                 D1(printk(KERN_DEBUG "zlib compressed %ld bytes into %ld; failing\n",
 117                           def_strm.total_in, def_strm.total_out));
 118                 ret = -1;
 119                 goto out;
 120         }
 121
 122         D1(printk(KERN_DEBUG "zlib compressed %ld bytes into %ld\n",
 123                   def_strm.total_in, def_strm.total_out));
 124
 125         *dstlen = def_strm.total_out;
 126         *sourcelen = def_strm.total_in;
 127         ret = 0;
 128  out:
 129         up(&deflate_sem);
 130         return ret;
 131 }
 132
 133 void jffs2_zlib_decompress(unsigned char *data_in, unsigned char *cpage_out,
 134                       uint32_t srclen, uint32_t destlen)
 135 {
 136         int ret;
 137         int wbits = MAX_WBITS;
 138
 139         down(&inflate_sem);
 140
 141         inf_strm.next_in = data_in;
 142         inf_strm.avail_in = srclen;
 143         inf_strm.total_in = 0;
 144
 145         inf_strm.next_out = cpage_out;
 146         inf_strm.avail_out = destlen;
 147         inf_strm.total_out = 0;
 148
 149         /* If it's deflate, and it's got no preset dictionary, then
 150            we can tell zlib to skip the adler32 check. */
 151         if (srclen > 2 && !(data_in[1] & PRESET_DICT) &&
 152             ((data_in[0] & 0x0f) == Z_DEFLATED) &&
 153             !(((data_in[0]<<8) + data_in[1]) % 31)) {
 154
 155                 D2(printk(KERN_DEBUG "inflate skipping adler32\n"));
 156                 wbits = -((data_in[0] >> 4) + 8);
 157                 inf_strm.next_in += 2;
 158                 inf_strm.avail_in -= 2;
 159         } else {
 160                 /* Let this remain D1 for now -- it should never happen */
 161                 D1(printk(KERN_DEBUG "inflate not skipping adler32\n"));
 162         }
 163
 164
 165         if (Z_OK != zlib_inflateInit2(&inf_strm, wbits)) {
 166                 printk(KERN_WARNING "inflateInit failed\n");
 167                 up(&inflate_sem);
 168                 return;
 169         }
 170
 171         while((ret = zlib_inflate(&inf_strm, Z_FINISH)) == Z_OK)
 172                 ;
 173         if (ret != Z_STREAM_END) {
 174                 printk(KERN_NOTICE "inflate returned %d\n", ret);
 175         }
 176         zlib_inflateEnd(&inf_strm);
 177         up(&inflate_sem);
 178 }