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318c9e430b
There is an error in the unlzma system in the kernel. A lzma compressed squashfs filesystem does not work for me. This should compile and works for me on my Asus WL-500GP, please test it on more systems. git-svn-id: svn://svn.openwrt.org/openwrt/trunk@16441 3c298f89-4303-0410-b956-a3cf2f4a3e73
230 lines
5.3 KiB
C
230 lines
5.3 KiB
C
/*
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* CFE environment variable access
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*
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* Copyright 2001-2003, Broadcom Corporation
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* Copyright 2006, Felix Fietkau <nbd@openwrt.org>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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*/
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/string.h>
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#include <asm/io.h>
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#include <asm/uaccess.h>
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#define NVRAM_SIZE (0x1ff0)
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static char _nvdata[NVRAM_SIZE];
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static char _valuestr[256];
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/*
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* TLV types. These codes are used in the "type-length-value"
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* encoding of the items stored in the NVRAM device (flash or EEPROM)
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*
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* The layout of the flash/nvram is as follows:
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*
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* <type> <length> <data ...> <type> <length> <data ...> <type_end>
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*
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* The type code of "ENV_TLV_TYPE_END" marks the end of the list.
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* The "length" field marks the length of the data section, not
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* including the type and length fields.
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*
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* Environment variables are stored as follows:
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*
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* <type_env> <length> <flags> <name> = <value>
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*
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* If bit 0 (low bit) is set, the length is an 8-bit value.
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* If bit 0 (low bit) is clear, the length is a 16-bit value
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*
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* Bit 7 set indicates "user" TLVs. In this case, bit 0 still
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* indicates the size of the length field.
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*
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* Flags are from the constants below:
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*
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*/
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#define ENV_LENGTH_16BITS 0x00 /* for low bit */
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#define ENV_LENGTH_8BITS 0x01
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#define ENV_TYPE_USER 0x80
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#define ENV_CODE_SYS(n,l) (((n)<<1)|(l))
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#define ENV_CODE_USER(n,l) ((((n)<<1)|(l)) | ENV_TYPE_USER)
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/*
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* The actual TLV types we support
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*/
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#define ENV_TLV_TYPE_END 0x00
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#define ENV_TLV_TYPE_ENV ENV_CODE_SYS(0,ENV_LENGTH_8BITS)
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/*
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* Environment variable flags
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*/
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#define ENV_FLG_NORMAL 0x00 /* normal read/write */
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#define ENV_FLG_BUILTIN 0x01 /* builtin - not stored in flash */
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#define ENV_FLG_READONLY 0x02 /* read-only - cannot be changed */
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#define ENV_FLG_MASK 0xFF /* mask of attributes we keep */
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#define ENV_FLG_ADMIN 0x100 /* lets us internally override permissions */
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/* *********************************************************************
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* _nvram_read(buffer,offset,length)
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*
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* Read data from the NVRAM device
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*
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* Input parameters:
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* buffer - destination buffer
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* offset - offset of data to read
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* length - number of bytes to read
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*
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* Return value:
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* number of bytes read, or <0 if error occured
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********************************************************************* */
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static int
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_nvram_read(unsigned char *nv_buf, unsigned char *buffer, int offset, int length)
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{
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int i;
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if (offset > NVRAM_SIZE)
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return -1;
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for ( i = 0; i < length; i++) {
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buffer[i] = ((volatile unsigned char*)nv_buf)[offset + i];
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}
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return length;
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}
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static char*
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_strnchr(const char *dest,int c,size_t cnt)
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{
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while (*dest && (cnt > 0)) {
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if (*dest == c) return (char *) dest;
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dest++;
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cnt--;
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}
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return NULL;
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}
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/*
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* Core support API: Externally visible.
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*/
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/*
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* Get the value of an NVRAM variable
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* @param name name of variable to get
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* @return value of variable or NULL if undefined
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*/
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char*
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cfe_env_get(unsigned char *nv_buf, char* name)
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{
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int size;
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unsigned char *buffer;
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unsigned char *ptr;
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unsigned char *envval;
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unsigned int reclen;
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unsigned int rectype;
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int offset;
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int flg;
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if (!strcmp(name, "nvram_type"))
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return "cfe";
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size = NVRAM_SIZE;
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buffer = &_nvdata[0];
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ptr = buffer;
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offset = 0;
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/* Read the record type and length */
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if (_nvram_read(nv_buf, ptr,offset,1) != 1) {
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goto error;
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}
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while ((*ptr != ENV_TLV_TYPE_END) && (size > 1)) {
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/* Adjust pointer for TLV type */
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rectype = *(ptr);
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offset++;
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size--;
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/*
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* Read the length. It can be either 1 or 2 bytes
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* depending on the code
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*/
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if (rectype & ENV_LENGTH_8BITS) {
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/* Read the record type and length - 8 bits */
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if (_nvram_read(nv_buf, ptr,offset,1) != 1) {
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goto error;
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}
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reclen = *(ptr);
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size--;
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offset++;
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}
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else {
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/* Read the record type and length - 16 bits, MSB first */
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if (_nvram_read(nv_buf, ptr,offset,2) != 2) {
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goto error;
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}
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reclen = (((unsigned int) *(ptr)) << 8) + (unsigned int) *(ptr+1);
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size -= 2;
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offset += 2;
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}
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if (reclen > size)
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break; /* should not happen, bad NVRAM */
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switch (rectype) {
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case ENV_TLV_TYPE_ENV:
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/* Read the TLV data */
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if (_nvram_read(nv_buf, ptr,offset,reclen) != reclen)
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goto error;
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flg = *ptr++;
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envval = (unsigned char *) _strnchr(ptr,'=',(reclen-1));
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if (envval) {
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*envval++ = '\0';
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memcpy(_valuestr,envval,(reclen-1)-(envval-ptr));
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_valuestr[(reclen-1)-(envval-ptr)] = '\0';
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#if 0
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printk(KERN_INFO "NVRAM:%s=%s\n", ptr, _valuestr);
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#endif
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if(!strcmp(ptr, name)){
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return _valuestr;
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}
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if((strlen(ptr) > 1) && !strcmp(&ptr[1], name))
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return _valuestr;
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}
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break;
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default:
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/* Unknown TLV type, skip it. */
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break;
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}
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/*
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* Advance to next TLV
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*/
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size -= (int)reclen;
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offset += reclen;
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/* Read the next record type */
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ptr = buffer;
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if (_nvram_read(nv_buf, ptr,offset,1) != 1)
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goto error;
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}
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error:
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return NULL;
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}
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