147 lines
4.1 KiB
C++
147 lines
4.1 KiB
C++
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/******************************************************************************
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COPYRIGHT(C) JONAS 'SORTIE' TERMANSEN 2011.
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This file is part of Sortix.
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Sortix is free software: you can redistribute it and/or modify it under the
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terms of the GNU General Public License as published by the Free Software
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Foundation, either version 3 of the License, or (at your option) any later
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version.
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Sortix is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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details.
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You should have received a copy of the GNU General Public License along
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with Sortix. If not, see <http://www.gnu.org/licenses/>.
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elf.h
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Constructs processes from ELF files.
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******************************************************************************/
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#include "platform.h"
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#include <libmaxsi/memory.h>
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#include "elf.h"
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#include "memorymanagement.h"
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#include "log.h" // DEBUG
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namespace Sortix
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{
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namespace ELF
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{
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addr_t Construct32(const void* file, size_t filelen)
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{
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if ( filelen < sizeof(Header32) ) { return 0; }
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const Header32* header = (const Header32*) file;
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// Check for little endian.
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if ( header->dataencoding != DATA2LSB ) { return 0; }
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if ( header->version != CURRENTVERSION ) { return 0; }
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addr_t entry = header->entry;
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// Find the location of the first section header.
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addr_t shtbloffset = header->sectionheaderoffset;
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addr_t shtblpos = ((addr_t) file) + shtbloffset;
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size_t shsize = header->sectionheaderentrysize;
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// Validate that all sections are present.
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uint16_t numsections = header->numsectionheaderentries;
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size_t neededfilelen = shtbloffset + numsections * shsize;
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if ( filelen < neededfilelen ) { return 0; }
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addr_t memlower = SIZE_MAX;
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addr_t memupper = 0;
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// Valid all the data we need is in the file.
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for ( uint16_t i = 0; i < numsections; i++ )
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{
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addr_t shoffset = i * shsize;
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addr_t shpos = shtblpos + shoffset;
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const SectionHeader32* sh = (const SectionHeader32*) shpos;
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if ( sh->addr == 0 ) { continue; }
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if ( sh->type == SHT_PROGBITS )
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{
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size_t sectionendsat = sh->offset + sh->size;
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if ( filelen < sectionendsat ) { return 0; }
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}
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if ( sh->type == SHT_PROGBITS || sh->type == SHT_NOBITS )
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{
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if ( sh->addr < memlower ) { memlower = sh->addr; }
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if ( memupper < sh->addr + sh->size ) { memupper = sh->addr + sh->size; }
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}
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}
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if ( memupper < memlower ) { return entry; }
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// HACK: For now just put it in the same continious block. This is
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// very wasteful and not very intelligent.
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addr_t mapto = Page::AlignDown(memlower);
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addr_t mapbytes = memupper - mapto;
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// TODO: Validate that we actually may map here!
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if ( !VirtualMemory::MapRangeUser(mapto, mapbytes) )
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{
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return 0;
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}
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// Create all the sections in the final process.
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for ( uint16_t i = 0; i < numsections; i++ )
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{
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addr_t shoffset = i * shsize;
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addr_t shpos = shtblpos + shoffset;
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const SectionHeader32* sh = (const SectionHeader32*) shpos;
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if ( sh->type != SHT_PROGBITS && sh->type != SHT_NOBITS )
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{
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continue;
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}
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if ( sh->addr == 0 ) { continue; }
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if ( sh->type == SHT_PROGBITS )
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{
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void* memdest = (void*) sh->addr;
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void* memsource = (void*) ( ((addr_t) file) + sh->offset );
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Maxsi::Memory::Copy(memdest, memsource, sh->size);
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}
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}
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// MEMORY LEAK: There is no system in place to delete the sections
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// once the process has terminated.
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return entry;
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}
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addr_t Construct64(const void* /*file*/, size_t /*filelen*/)
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{
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return 0;
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}
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addr_t Construct(const void* file, size_t filelen)
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{
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if ( filelen < sizeof(Header) ) { return 0; }
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const Header* header = (const Header*) file;
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if ( !(header->magic[0] == 0x7F && header->magic[1] == 'E' &&
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header->magic[2] == 'L' && header->magic[3] == 'F' ) )
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{
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return 0;
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}
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switch ( header->fileclass )
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{
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case CLASS32:
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return Construct32(file, filelen);
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case CLASS64:
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return Construct64(file, filelen);
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default:
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return 0;
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}
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}
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}
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}
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