ecos: packages/services/objloader/current/src/objloader.c comparison

comparison packages/services/objloader/current/src/objloader.c @ 2011:662e1b34b811

Added OBJLOADER package.

author	nickg
date	Thu, 07 Jul 2005 10:55:12 +0000
parents
children	8bf90d16b837

comparison

equal deleted inserted replaced

-:2379473fdc8d
+:662e1b34b811
+/* =================================================================
+*
+*      objelf.c
+*
+*      An object loader for eCos
+*
+* =================================================================
+* ####ECOSGPLCOPYRIGHTBEGIN####
+* -------------------------------------------
+* This file is part of eCos, the Embedded Configurable Operating
+* System.
+* Copyright (C) 2005 eCosCentric Ltd.
+*
+* 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.
+*
+* -------------------------------------------
+* ####ECOSGPLCOPYRIGHTEND####
+* =================================================================
+* #####DESCRIPTIONBEGIN####
+*
+*  Author(s):    atonizzo@lycos.com
+*  Contributors: nickg@ecoscentric.com
+*  Date:         2005-05-13
+*  Purpose:
+*  Description:
+*
+* ####DESCRIPTIONEND####
+*
+* =================================================================
+*/
+#include <cyg/infra/diag.h>     // For diagnostic printing.
+#include <cyg/infra/cyg_ass.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <pkgconf/objloader.h>
+#include <cyg/objloader/elf.h>
+#include <cyg/objloader/objelf.h>
+#include <cyg/objloader/loader_fs.h>
+cyg_uint8 *cyg_ldr_last_error;
+void *cyg_ldr_malloc( size_t ) CYGBLD_ATTRIB_WEAK;
+void
+*cyg_ldr_malloc( size_t s )
+{
+return malloc( s );
+}
+void cyg_ldr_free( void * ) CYGBLD_ATTRIB_WEAK;
+void
+cyg_ldr_free( void *s )
+{
+free( s );
+}
+void
+cyg_ldr_delete_elf_section( PELF_OBJECT p, cyg_uint32 idx )
+{
+cyg_ldr_free( p->sections[idx] );
+p->sections[idx] = 0;
+}
+// Frees all the memory allocated for a particular ELF object. Also calls
+//  the close() function to close files or sockets, and finally frees up
+//  the ELF object altogether.
+static void
+cyg_ldr_free_elf_object( PELF_OBJECT p )
+{
+cyg_int32 i;
+for ( i = 0; i < p->p_elfhdr->e_shnum + 1; i++ )
+if ( p->sections[i] )
+cyg_ldr_delete_elf_section( p, i );
+if ( p->sections != 0 )
+cyg_ldr_free( p->sections );
+if ( p->p_sechdr != 0 )
+cyg_ldr_free( p->p_sechdr );
+if ( p->p_elfhdr != 0 )
+cyg_ldr_free( p->p_elfhdr );
+p->close( p );
+cyg_ldr_free( p );
+}
+static cyg_uint32
+cyg_ldr_find_common_size( PELF_OBJECT p )
+{
+cyg_int32 i, symtab_entries, common_size = 0;
+Elf32_Sym *p_symtab = (Elf32_Sym*)p->sections[p->hdrndx_symtab];
+// Total number of entries in the symbol table.
+symtab_entries = p->p_sechdr[p->hdrndx_symtab].sh_size /
+p->p_sechdr[p->hdrndx_symtab].sh_entsize;
+for ( i = 1; i < symtab_entries; i++ )
+if ( p_symtab[i].st_shndx == SHN_COMMON )
+{
+// In the case of an SHN_COMMON symbol the st_value field holds
+//  alignment constraints.
+cyg_uint32 boundary = p_symtab[i].st_value - 1;
+// Calculate the next byte boundary.
+common_size = ( common_size + boundary ) & ~boundary;
+common_size += p_symtab[i].st_size;
+}
+#if CYGPKG_SERVICES_OBJLOADER_DEBUG_LEVEL > 0
+diag_printf( "common_size = %d\n", common_size );
+#endif
+return common_size;
+}
+// Allocates memory and loads the contents of a specific ELF section.
+// Returns the address of the newly allocated memory, of 0 for any error.
+cyg_int32
+*cyg_ldr_load_elf_section( PELF_OBJECT p, cyg_uint32 idx )
+{
+cyg_uint32 *addr;
+addr = cyg_ldr_malloc( p->p_sechdr[idx].sh_size );
+CYG_ASSERT( addr != 0, "Cannot malloc() section" );
+if ( addr == 0 )
+{
+cyg_ldr_last_error = "ERROR IN MALLOC";
+return (void*)0;
+}
+p->seek( p, p->p_sechdr[idx].sh_offset );
+p->read( p, sizeof( char ), p->p_sechdr[idx].sh_size, addr );
+return addr;
+}
+// Returns the starting address of a section. If the section is not already
+//  loaded in memory, area for it will be allocated and the section will be
+//  loaded.
+cyg_int32
+*cyg_ldr_section_address( PELF_OBJECT p, cyg_uint32 idx )
+{
+if ( p->sections[idx] == 0 )
+p->sections[idx] = cyg_ldr_load_elf_section( p, idx );
+return p->sections[idx];
+}
+void
+*cyg_ldr_find_symbol( void* handle, cyg_uint8* sym_name )
+{
+PELF_OBJECT p = (PELF_OBJECT)handle;
+cyg_uint8* tmp2;
+cyg_int32  i, symtab_entries;
+cyg_uint8 *p_strtab = (cyg_uint8*)p->sections[p->hdrndx_strtab];
+Elf32_Sym *p_symtab = (Elf32_Sym*)p->sections[p->hdrndx_symtab];
+symtab_entries = p->p_sechdr[p->hdrndx_symtab].sh_size /
+p->p_sechdr[p->hdrndx_symtab].sh_entsize;
+for ( i = 0; i < symtab_entries; i++ )
+{
+tmp2 = p_strtab + p_symtab[i].st_name;
+if ( !strcmp( tmp2, sym_name ) )
+return cyg_ldr_symbol_address( p, i );
+}
+// Symbol not found.
+cyg_ldr_last_error = "SYMBOL NOT FOUND";
+return 0;
+}
+static cyg_uint8
+*cyg_ldr_sanity_check( PELF_OBJECT p )
+{
+if ( ( p->p_elfhdr->e_ident[EI_MAG0] != ELFMAG0 )  ||
+( p->p_elfhdr->e_ident[EI_MAG1] != ELFMAG1 )  ||
+( p->p_elfhdr->e_ident[EI_MAG2] != ELFMAG2  ) ||
+( p->p_elfhdr->e_ident[EI_MAG3] != ELFMAG3 )  ||
+( p->p_elfhdr->e_ident[EI_CLASS] != ELFCLASS32 ) )
+return "INVALID ELF HEADER";
+// We only work with relocatable files. No dynamic linking.
+if ( p->p_elfhdr->e_type != ET_REL )
+return "NOT RELOCATABLE";
+// These #defines are sitting in the hal.
+if ( p->p_elfhdr->e_machine != ELF_ARCH_MACHINE_TYPE )
+return "INVALID ARCHITECTURE";
+if ( p->p_elfhdr->e_ident[EI_DATA] != ELF_ARCH_ENDIANNESS )
+return "INVALID ENDIAN";
+return 0;  }
+// Load only the ELF header and the sections header. These are the only
+//  sections loaded during library initialization. All the other sections
+//  will be loaded on demand when needed during the relocation process and,
+//  when possible, dumped after use.
+static cyg_int32
+cyg_ldr_load_sections( PELF_OBJECT p )
+{
+cyg_uint8  *error_string;
+cyg_int32  idx;
+// Load the ELF header.
+p->p_elfhdr = (Elf32_Ehdr*)cyg_ldr_malloc( sizeof( Elf32_Ehdr ) );
+CYG_ASSERT( p->p_elfhdr != 0, "Cannot malloc() p->p_elfhdr" );
+if ( p->p_elfhdr == 0 )
+return -1;
+p->seek( p, 0 );
+p->read( p, sizeof( char ), sizeof( Elf32_Ehdr ), p->p_elfhdr  );
+error_string = cyg_ldr_sanity_check( p );
+if ( error_string != 0 )
+{
+cyg_ldr_last_error = "ERROR IN ELF HEADER";
+return -1;
+}
+// Allocate an array that can hold an address to all the section of this
+//  library. This is not strictly optimal, since some sections do not
+//  need to be loaded all the time. Allocate an extra pointer for the
+//  COMMON area.
+p->sections = cyg_ldr_malloc( ( p->p_elfhdr->e_shnum + 1 ) *
+sizeof( cyg_uint32 ) );
+CYG_ASSERT( p->sections != 0, "Cannot malloc() p->sections" );
+if ( p->sections == 0 )
+{
+cyg_ldr_last_error = "ERROR IN MALLOC";
+return -1;
+}
+memset( p->sections, 0, ( p->p_elfhdr->e_shnum + 1 ) *
+sizeof( cyg_uint32 ) );
+// Now that the header is loaded, load the sections header.
+p->p_sechdr = (Elf32_Shdr*)cyg_ldr_malloc(
+p->p_elfhdr->e_shnum * p->p_elfhdr->e_shentsize );
+CYG_ASSERT( p->p_sechdr != 0, "Cannot malloc() p->p_sechdr" );
+if ( p->p_sechdr == 0 )
+{
+cyg_ldr_last_error = "ERROR IN MALLOC";
+return -1;
+}
+p->seek( p, p->p_elfhdr->e_shoff );
+p->read( p, p->p_elfhdr->e_shentsize, p->p_elfhdr->e_shnum, p->p_sechdr );
+// Load the section header string table. This is a byte oriented table,
+//  so alignment is not an issue.
+idx = p->p_elfhdr->e_shstrndx;
+p->sections[idx] = cyg_ldr_load_elf_section( p, idx );
+return 0;
+}
+PELF_OBJECT
+cyg_ldr_open_library( CYG_ADDRWORD ptr, cyg_int32 mode )
+{
+Elf32_Sym *p_symtab;
+cyg_uint8 *p_shstrtab;
+PELF_OBJECT e_obj;
+int (*fn)(void);
+cyg_int32   i, rc, symtab_entries;
+cyg_uint32  common_size;
+// In the future there might be a switch() (against 'mode') that calls an
+//  open function other than cyg_ldr_open_library_fs(). These function
+//  fetch and open a library using ftp, http or libraries that are already
+//  in ROM.
+e_obj = cyg_ldr_open_library_fs( (cyg_uint8*)ptr );
+if ( e_obj == 0 )
+return 0;
+rc = cyg_ldr_load_sections( e_obj );
+if ( rc != 0 )
+{
+cyg_ldr_free_elf_object( e_obj );
+return 0;
+}
+// Find the section index for the .shstrtab section. The names of the
+//  sections are held here, and are the only way to identify them.
+p_shstrtab = (cyg_uint8*)cyg_ldr_section_address( e_obj,
+e_obj->p_elfhdr->e_shstrndx );
+if ( p_shstrtab == 0 )
+{
+cyg_ldr_free_elf_object( e_obj );
+return 0;
+}
+// .symtab section and .strtab. We have to go through the section names
+//  to find where they are.
+for ( i = 1; i < e_obj->p_elfhdr->e_shnum; i++ )
+{
+// Now look for the index of .symtab. These are the symbols needed for
+//  the symbol retrieval as well as relocation.
+if ( !strcmp( p_shstrtab + e_obj->p_sechdr[i].sh_name,
+ELF_STRING_symtab ) )
+{
+e_obj->hdrndx_symtab = i;
+e_obj->sections[i] = cyg_ldr_load_elf_section( e_obj, i );
+if ( e_obj->sections[i] == 0 )
+{
+cyg_ldr_free_elf_object( e_obj );
+return 0;
+}
+}
+// Load the table with the names of all the symbols. We need this
+//  to compare the name of external references symbols against the
+//  names in the in the CYG_HAL_TABLE provided by the user.
+if ( !strcmp( p_shstrtab + e_obj->p_sechdr[i].sh_name,
+ELF_STRING_strtab ) )
+{
+e_obj->hdrndx_strtab = i;
+e_obj->sections[i] = cyg_ldr_load_elf_section( e_obj, i );
+if ( e_obj->sections[i] == 0 )
+{
+cyg_ldr_free_elf_object( e_obj );
+return 0;
+}
+}
+}
+CYG_ASSERT( e_obj->hdrndx_symtab != 0, "No symtab index found" );
+CYG_ASSERT( e_obj->hdrndx_strtab != 0, "No strtab index found" );
+// Now look for symbols in the COMMON area. The COMMON symbols are a
+//  special case, because the area they reside in must be sized up
+//  and allocated separately from the other sections, which appear in
+//  the sections header and can be read out of the library itself.
+// Extra room in the 'sections' array has already been allocated to hold
+//  the pointer to the commons area.
+common_size = cyg_ldr_find_common_size( e_obj );
+if ( common_size != 0 )
+{
+cyg_uint32 com_shndx = e_obj->p_elfhdr->e_shnum;
+cyg_int32  com_offset = 0;
+e_obj->sections[com_shndx] = (cyg_uint32*)cyg_ldr_malloc( common_size );
+CYG_ASSERT( e_obj->sections[com_shndx] != 0,
+"Cannot malloc() the COMMONS" );
+if ( e_obj->sections[com_shndx] == 0 )
+{
+cyg_ldr_free_elf_object( e_obj );
+return 0;
+}
+// Now find all the symbols in the SHN_COMMON area and make
+//  them  point to the newly allocated COM area.
+symtab_entries = e_obj->p_sechdr[e_obj->hdrndx_symtab].sh_size /
+e_obj->p_sechdr[e_obj->hdrndx_symtab].sh_entsize;
+p_symtab = (Elf32_Sym*)e_obj->sections[e_obj->hdrndx_symtab];
+#if CYGPKG_SERVICES_OBJLOADER_DEBUG_LEVEL > 1
+diag_printf( "Num   Value   Size Ndx Name\n" );
+#endif
+for ( i = 1; i < symtab_entries; i++ )
+{
+#if CYGPKG_SERVICES_OBJLOADER_DEBUG_LEVEL > 1
+cyg_uint8 *p_strtab = (cyg_uint8*)cyg_ldr_section_address( e_obj,
+e_obj->hdrndx_strtab );
+#endif
+if ( p_symtab[i].st_shndx == SHN_COMMON )
+{
+cyg_uint32 boundary = p_symtab[i].st_value - 1;
+// Calculate the next byte boundary.
+com_offset = ( com_offset + boundary ) & ~boundary;
+p_symtab[i].st_shndx = com_shndx;
+p_symtab[i].st_value = com_offset;
+com_offset += p_symtab[i].st_size;
+}
+#if CYGPKG_SERVICES_OBJLOADER_DEBUG_LEVEL > 1
+diag_printf( "%03d  %08X %04X %03d %s\n",
+i,
+p_symtab[i].st_value,
+p_symtab[i].st_size,
+p_symtab[i].st_shndx,
+p_strtab + p_symtab[i].st_name );
+#endif
+}
+}
+#if CYGPKG_SERVICES_OBJLOADER_DEBUG_LEVEL > 0
+cyg_ldr_print_section_data( e_obj );
+#if CYGPKG_SERVICES_OBJLOADER_DEBUG_LEVEL > 1
+cyg_ldr_print_symbol_names( e_obj );
+#endif
+#endif
+for ( i = 1; i < e_obj->p_elfhdr->e_shnum; i++ )
+{
+// Find all the '.rel' or '.rela' sections and relocate them.
+if ( ( e_obj->p_sechdr[i].sh_type == SHT_REL ) ||
+( e_obj->p_sechdr[i].sh_type == SHT_RELA ) )
+{
+// Load and relocate the section.
+rc = cyg_ldr_relocate_section( e_obj, i );
+if ( rc < 0 )
+{
+#if CYGPKG_SERVICES_OBJLOADER_DEBUG_LEVEL > 0
+ELFDEBUG( "Relocation unsuccessful\n" );
+#endif
+cyg_ldr_free_elf_object( e_obj );
+return 0;
+}
+}
+}
+// Synch up the caches before calling any function in the library.
+cyg_ldr_flush_cache();
+// Run the library initialization code.
+fn = cyg_ldr_find_symbol( e_obj, "library_open" );
+if ( fn != 0 )
+fn();
+return ((void*)e_obj);
+}
+cyg_uint8
+*cyg_ldr_error( void )
+{
+cyg_uint8* p = cyg_ldr_last_error;
+cyg_ldr_last_error = NULL;
+return p;
+}
+void cyg_ldr_close_library( void* handle )
+{
+void (*fn)(void);
+PELF_OBJECT p = (PELF_OBJECT)handle;
+fn = cyg_ldr_find_symbol( p, "library_close" );
+if ( fn != 0 )
+fn();
+cyg_ldr_free_elf_object( p );
+p = 0;
+}

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comparison packages/services/objloader/current/src/objloader.c @ 2011:662e1b34b811