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#ifndef CYGONCE_LOADER_LOADER_HXX
#define CYGONCE_LOADER_LOADER_HXX
//==========================================================================
//
// loader.hxx
//
// ELF dynamic loader definitions
//
//==========================================================================
//####ECOSGPLCOPYRIGHTBEGIN####
// -------------------------------------------
// This file is part of eCos, the Embedded Configurable Operating System.
// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.
//
// eCos is free software; you can redistribute it and/or modify it under
// the terms of the GNU General Public License as published by the Free
// Software Foundation; either version 2 or (at your option) any later version.
//
// eCos is distributed in the hope that it will be useful, but WITHOUT ANY
// WARRANTY; without even the implied warranty of MERCHANTABILITY or
// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
// for more details.
//
// You should have received a copy of the GNU General Public License along
// with eCos; if not, write to the Free Software Foundation, Inc.,
// 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
//
// As a special exception, if other files instantiate templates or use macros
// or inline functions from this file, or you compile this file and link it
// with other works to produce a work based on this file, this file does not
// by itself cause the resulting work to be covered by the GNU General Public
// License. However the source code for this file must still be made available
// in accordance with section (3) of the GNU General Public License.
//
// This exception does not invalidate any other reasons why a work based on
// this file might be covered by the GNU General Public License.
//
// Alternative licenses for eCos may be arranged by contacting Red Hat, Inc.
// at http://sources.redhat.com/ecos/ecos-license/
// -------------------------------------------
//####ECOSGPLCOPYRIGHTEND####
//==========================================================================
//#####DESCRIPTIONBEGIN####
//
// Author(s): nickg
// Contributors: nickg
// Date: 2000-11-15
// Purpose: Define ELF dynamic loader
// Description: The classes defined here collectively implement the
// internal API of the ELF dynamic loader.
// Usage: #include <cyg/loader/loader.hxx>
//
//####DESCRIPTIONEND####
//
//==========================================================================
#include <pkgconf/system.h>
#ifndef CYG_LOADER_DYNAMIC_LD
#include <cyg/loader/elf.h> // ELF data structures
#ifdef __cplusplus
#include <cyg/kernel/ktypes.h>
#include <cyg/infra/cyg_ass.h> // assertion macros
#include <cyg/infra/clist.hxx>
// -------------------------------------------------------------------------
// Forward definitions
class Cyg_LoaderStream;
class Cyg_LoaderMemBlock;
class Cyg_LoaderMemAlloc;
class Cyg_LoadObject_Base;
class Cyg_LoadObject_Proc;
class Cyg_LoadObject;
class Cyg_Loader;
// -------------------------------------------------------------------------
// Error codes
#define CYG_LOADERR_NOERROR 0 // No error
#define CYG_LOADERR_NOT_ELF 1 // Not ELF format file
#define CYG_LOADERR_INVALID_CLASS 2 // Not expected file class
#define CYG_LOADERR_INVALID_BYTEORDER 3 // Not expected byte order
#define CYG_LOADERR_INVALID_VERSION 4 // Not expected ELF version
#define CYG_LOADERR_INVALID_MACHINE 5 // Not expected machine type
#define CYG_LOADERR_NO_MEMORY 6 // No memory
#define CYG_LOADERR_EOF 7 // End of input stream
#define CYG_LOADERR_SEEK 8 // Cannot seek to stream position
#define CYG_LOADERR_INVALID_RELOC 9 // Invalid or unexpected relocation
#define CYG_LOADERR_NO_HASHTABLE 10 // No hash table in ELF file
#define CYG_LOADERR_NO_SYMTAB 11 // No symbol table in ELF file
#define CYG_LOADERR_NO_STRTAB 12 // No srting table in ELF file
#define CYG_LOADERR_NO_SYMBOL 13 // Symbol not found
// -------------------------------------------------------------------------
// Value for undefined or otherwise invalid symbol addresses.
#define CYG_LOADER_NULLSYMADDR 0
// -------------------------------------------------------------------------
// Loader Stream base class.
// This defines the interface to data streams that are ELF dynamic executable
// files.
class Cyg_LoaderStream
{
public:
Cyg_LoaderStream(); // Constructor
virtual ~Cyg_LoaderStream(); // Destructor
// The following functions are virtual and are supplied by a
// derived class to access to data stream.
virtual cyg_code get_byte(CYG_BYTE *val); // Get a byte from the stream
virtual cyg_code get_data(CYG_BYTE *addr, CYG_ADDRWORD size);
virtual cyg_code seek(CYG_ADDRWORD pos); // seek to given position
// The following functions all make use of the virtual functions
// to access the data stream.
cyg_code get_word16(CYG_WORD16 *val); // get a 16 bit value
cyg_code get_word32(CYG_WORD32 *val); // get a 32 bit value
cyg_code get_word64(CYG_WORD64 *val); // get a 64 bit value
};
// -------------------------------------------------------------------------
// Memory allocation object. All memory allocated by the Loader is described
// by one of these.
struct Cyg_LoaderMemBlock
: public Cyg_DNode_T<Cyg_LoaderMemBlock>
{
void *address; // data address
cyg_int32 size; // block size
cyg_int32 alignment; // block alignment
Cyg_LoaderMemAlloc *mem; // allocator used
CYG_ADDRESS actual_address; // allocator specific actual address for block
CYG_WORD32 actual_size; // allocator specific actual size for block
// Convenience free() function
void free();
};
// -------------------------------------------------------------------------
// Memory allocator base class
// This defines the interface to a memory allocator used by the loader.
class Cyg_LoaderMemAlloc
{
public:
Cyg_LoaderMemAlloc();
virtual ~Cyg_LoaderMemAlloc();
// The following functions are virtual so that alternative memory
// allocators may be implemented. The default behaviour of this
// class is to use malloc/realloc/free to support these functions.
// Allocate memory of the supplied size and alignment.
// size - size in bytes
// alignment - alignment expressed as a power of 2
// defaults to 8 byte alignment
virtual Cyg_LoaderMemBlock *alloc( cyg_int32 size,
cyg_int32 alignment = 8);
// Reallocate block
// block - block to reallocate
// size - new size in bytes
// alignment - new alignment, -1 if old alignment is to be used.
virtual Cyg_LoaderMemBlock *realloc( Cyg_LoaderMemBlock *block,
cyg_int32 size,
cyg_int32 alignment = -1);
// Free a previously allocated memory segment.
virtual void free( Cyg_LoaderMemBlock *block );
};
// -------------------------------------------------------------------------
// Cyg_LoaderMemBlock convenience free() function implementation.
inline void Cyg_LoaderMemBlock::free() { mem->free(this); };
// -------------------------------------------------------------------------
// A loaded object
class Cyg_LoadObject_Base
: public Cyg_DNode_T<Cyg_LoadObject>
{
friend class Cyg_Loader;
protected:
// The following fields come from the constructor arguments
cyg_uint32 mode; // mode flags
Cyg_LoaderMemAlloc *memalloc; // Memory allocator
// The following fields are derived from the ELF header
Elf32_Word e_type; // File type
Elf32_Addr e_entry; // Executable entry point
// The following fields are derived from the PT_DYNAMIC segment in
// the program header. These fields are named after the DT_ tags
// that their values are derived from.
Elf32_Word flags; // flags from DT_FLAGS
Elf32_Word soname; // name of module, if defined
Elf_Hash *hash; // address of hash table
Elf32_Word *bucket; // derived bucket array address
Elf32_Word *chain; // derived chain array address
// String table
unsigned char *strtab; // address of table
Elf32_Word strsize; // size of table in bytes
// Symbol table
Elf32_Sym *symtab; // address of table
Elf32_Word syment; // size of entry
// PTL and GOT
Elf32_Addr pltgot; // address of PLT and/or GOT
// PLT relocation entries
Elf32_Addr jmprel; // address of relocation table
Elf32_Word pltrelsz; // size of jmprel table in bytes
Elf32_Word pltrel; // type of table entries: DT_REL
// or DT_RELA
// Relocation table with implicit addends
Elf32_Rel *rel; // table address
Elf32_Word relsize; // table size in bytes
Elf32_Word relent; // size of entry
// Relocation table with explicit addends
Elf32_Rela *rela; // table address
Elf32_Word relasize; // table size in bytes
Elf32_Word relaent; // size of entry
// Init and Fini support
Elf32_Addr init; // address of init function
Elf32_Addr fini; // address of fini function
Elf32_Addr *init_array; // address of init array
Elf32_Word init_array_sz; // size of init array
Elf32_Addr *fini_array; // address of fini array
Elf32_Word fini_array_sz; // size of fini array
Elf32_Addr *pre_init_array; // address of pre_init array
Elf32_Word pre_init_array_sz; // size of pre_init array
Elf32_Dyn *dynamic; // address of _DYNAMIC section
CYG_ADDRESS base; // base address used in address and
// relocation calcualtions
Cyg_CList_T<Cyg_LoaderMemBlock> segs; // chain of loaded segments
cyg_code error; // most recent error code
// private functions
void parse_dynamic( Elf32_Dyn *dynamic );
// Translate a symbol from its symbol table index into its
// actual address
CYG_ADDRESS get_sym_addr_from_ix( Elf32_Word sym );
// Get a symbol from this object's symbol table.
Elf32_Sym *get_sym( Elf32_Word ix );
// Get a name from this object's string table.
char *get_name( Elf32_Word offset );
// Look up the name in the hash table and return its symbol
// table entry, or NULL if not found.
Elf32_Sym *hash_lookup( const char *name );
// Look up the name in the hash table and return its absolute
// address or CYG_LOADER_NULLSYMADDR if it is not found.
CYG_ADDRESS hash_lookup_addr( const char *name );
// Standard ELF-defined hash function for symbol table.
static unsigned long elf_hash( const unsigned char *name );
public:
// Constructor - reads and allocates the executable.
Cyg_LoadObject_Base();
Cyg_LoadObject_Base( Cyg_LoaderStream& stream,
cyg_uint32 mode,
Cyg_LoaderMemAlloc *mem );
~Cyg_LoadObject_Base(); // Destructor
inline cyg_code get_error() { return error; };
// Translate a symbol into its address.
void *symbol( const char *name );
// Start this executable running
cyg_code exec(int argc, char **argv, char **envv);
};
#endif // __cplusplus
#endif // CYG_LOADER_DYNAMIC_LD
// -------------------------------------------------------------------------
// All the following files should have suitable ifdefs so that only
// one actually provides content.
#include <cyg/loader/mips_elf.h> // MIPS ELF support
#include <cyg/loader/arm_elf.h> // ARM ELF support
#include <cyg/loader/i386_elf.h> // i386 ELF support
#include <cyg/loader/ppc_elf.h> // PowerPC ELF support
//#include <cyg/loader/sparc_elf.h> // Sparc ELF support
//#include <cyg/loader/sh_elf.h> // SH ELF support
// -------------------------------------------------------------------------
#ifndef CYG_LOADER_DYNAMIC_LD
#ifdef __cplusplus
class Cyg_LoadObject :
public Cyg_LoadObject_Proc
{
Cyg_LoaderMemBlock *block;
public:
inline Cyg_LoadObject()
: Cyg_LoadObject_Proc()
{
};
inline Cyg_LoadObject( Cyg_LoaderStream& stream,
cyg_uint32 mode,
Cyg_LoaderMemAlloc *mem,
Cyg_LoaderMemBlock *ablock = NULL)
: Cyg_LoadObject_Proc( stream, mode, mem )
{
block = ablock;
};
inline ~Cyg_LoadObject() {};
Cyg_LoaderMemBlock *get_block() { return block; };
// Apply dynamic relocations to the executable
void relocate();
// Apply PLT relocations
void relocate_plt();
};
// -------------------------------------------------------------------------
// Main loader class
class Cyg_Loader
{
// current error code.
cyg_code error;
// Default memory allocator.
Cyg_LoaderMemAlloc *mem_default;
// Load object for main program
Cyg_LoadObject *main;
// List of loaded executables, including the main
// program and all libraries.
Cyg_CList_T<Cyg_LoadObject> loadlist;
public:
Cyg_Loader( Cyg_LoaderMemAlloc *mem); // Constructor
~Cyg_Loader(); // Destructor
// Load an object and all its dependencies.
cyg_code load( Cyg_LoaderStream& stream,
cyg_uint32 mode,
Cyg_LoadObject **object);
// Close an object and remove it from memory
cyg_code close( Cyg_LoadObject *object );
// Translate current error code into a string.
const char *error_string( );
// Look up a symbol
Elf32_Sym *hash_lookup( const char *name );
// look up a named symbol in loadlist and return its
// address relocated to its load address.
CYG_ADDRESS hash_lookup_addr( const char *name );
// Static pointer to loader object
static Cyg_Loader *loader;
};
//==========================================================================
// Memory based loader stream
class Cyg_LoaderStream_Mem
: public Cyg_LoaderStream
{
CYG_ADDRESS base;
CYG_ADDRESS pos;
CYG_ADDRESS end;
public:
Cyg_LoaderStream_Mem( const void *addr, cyg_int32 size );
~Cyg_LoaderStream_Mem(); // Destructor
cyg_code get_byte(CYG_BYTE *val); // Get a byte from the stream
cyg_code get_data(CYG_BYTE *addr, CYG_ADDRWORD size);
cyg_code seek(CYG_ADDRWORD pos); // seek to given position
};
//==========================================================================
// Fileio based loader stream
#ifdef CYGPKG_IO_FILEIO
class Cyg_LoaderStream_File
: public Cyg_LoaderStream
{
int fd;
public:
Cyg_LoaderStream_File( int afd );
~Cyg_LoaderStream_File(); // Destructor
cyg_code get_byte(CYG_BYTE *val); // Get a byte from the stream
cyg_code get_data(CYG_BYTE *addr, CYG_ADDRWORD size);
cyg_code seek(CYG_ADDRWORD pos); // seek to given position
};
#endif
// -------------------------------------------------------------------------
#endif // __cplusplus
#endif // CYG_LOADER_DYNAMIC_LD
// -------------------------------------------------------------------------
#endif // ifndef CYGONCE_LOADER_LOADER_HXX
// EOF loader.hxx
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