Sortix can now load ELF executables into addresses spaces.

sortix/Makefile

@@ -44,7 +44,7 @@ DEFINES:=$(DEFINES) -DINITRD
 CPPFLAGSRELEASE=-s -O3
 CPPFLAGSDEBUG=
 CPPFLAGS=-I.. -I. $(CPUDEFINES) $(CPUFLAGS) -std=gnu++0x -Wall -Wextra -nostdlib -fno-builtin -nostartfiles -nodefaultlibs -fno-exceptions -fno-rtti -fno-stack-protector $(DEFINES) $(CPPFLAGSRELEASE)
-OBJS=$(CPUOBJS) kernel.o descriptor_tables.o isr.o time.o log.o iprintable.o panic.o keyboard.o memorymanagement.o scheduler.o syscall.o application.o pong.o sound.o pci.o uart.o conway.o test.o http.o vgaterminal.o serialterminal.o descriptors.o device.o vga.o ../libmaxsi/libmaxsi-sortix.a
+OBJS=$(CPUOBJS) kernel.o descriptor_tables.o isr.o time.o log.o iprintable.o panic.o keyboard.o memorymanagement.o scheduler.o syscall.o application.o pong.o sound.o pci.o uart.o conway.o test.o http.o vgaterminal.o serialterminal.o descriptors.o device.o vga.o elf.o ../libmaxsi/libmaxsi-sortix.a
 JSOBJS:=$(subst .o,-js.o,$(OBJS))
 
 all: sortix.bin

sortix/elf.cpp

@@ -0,0 +1,146 @@
+/******************************************************************************
+
+	COPYRIGHT(C) JONAS 'SORTIE' TERMANSEN 2011.
+
+	This file is part of Sortix.
+
+	Sortix 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 3 of the License, or (at your option) any later
+	version.
+
+	Sortix 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 Sortix. If not, see <http://www.gnu.org/licenses/>.
+
+	elf.h
+	Constructs processes from ELF files.
+
+******************************************************************************/
+
+#include "platform.h"
+#include <libmaxsi/memory.h>
+#include "elf.h"
+#include "memorymanagement.h"
+
+#include "log.h" // DEBUG
+
+namespace Sortix
+{
+	namespace ELF
+	{
+		addr_t Construct32(const void* file, size_t filelen)
+		{
+			if ( filelen < sizeof(Header32) ) { return 0; }
+			const Header32* header = (const Header32*) file;
+
+			// Check for little endian.
+			if ( header->dataencoding != DATA2LSB ) { return 0; }
+			if ( header->version != CURRENTVERSION ) { return 0; }
+
+			addr_t entry = header->entry;
+
+			// Find the location of the first section header.
+			addr_t shtbloffset = header->sectionheaderoffset;
+			addr_t shtblpos = ((addr_t) file) + shtbloffset;
+			size_t shsize = header->sectionheaderentrysize;
+
+			// Validate that all sections are present.
+			uint16_t numsections = header->numsectionheaderentries;
+			size_t neededfilelen = shtbloffset + numsections * shsize;
+			if ( filelen < neededfilelen ) { return 0; } 
+
+			addr_t memlower = SIZE_MAX;
+			addr_t memupper = 0;
+
+			// Valid all the data we need is in the file.
+			for ( uint16_t i = 0; i < numsections; i++ )
+			{
+				addr_t shoffset = i * shsize;
+				addr_t shpos = shtblpos + shoffset;
+				const SectionHeader32* sh = (const SectionHeader32*) shpos;
+				if ( sh->addr == 0 ) { continue; }
+				if ( sh->type == SHT_PROGBITS )
+				{
+					size_t sectionendsat = sh->offset + sh->size;
+					if ( filelen < sectionendsat ) { return 0; }
+				}
+				if ( sh->type == SHT_PROGBITS || sh->type == SHT_NOBITS )
+				{
+					if ( sh->addr < memlower ) { memlower = sh->addr; }
+					if ( memupper < sh->addr + sh->size ) { memupper = sh->addr + sh->size; }
+				}
+			}
+
+			if ( memupper < memlower ) { return entry; }
+
+			// HACK: For now just put it in the same continious block. This is
+			// very wasteful and not very intelligent.
+			addr_t mapto = Page::AlignDown(memlower);
+			addr_t mapbytes = memupper - mapto;
+			// TODO: Validate that we actually may map here!
+			if ( !VirtualMemory::MapRangeUser(mapto, mapbytes) )
+			{
+				return 0;
+			}
+
+			// Create all the sections in the final process.
+			for ( uint16_t i = 0; i < numsections; i++ )
+			{
+				addr_t shoffset = i * shsize;
+				addr_t shpos = shtblpos + shoffset;
+				const SectionHeader32* sh = (const SectionHeader32*) shpos;
+				if ( sh->type != SHT_PROGBITS && sh->type != SHT_NOBITS )
+				{
+					continue;
+				}
+
+				if ( sh->addr == 0 ) { continue; }
+
+				if ( sh->type == SHT_PROGBITS )
+				{
+					void* memdest = (void*) sh->addr;
+					void* memsource = (void*) ( ((addr_t) file) + sh->offset );
+					Maxsi::Memory::Copy(memdest, memsource, sh->size);
+				}
+			}
+
+			// MEMORY LEAK: There is no system in place to delete the sections
+			// once the process has terminated.
+
+			return entry;
+		}
+
+		addr_t Construct64(const void* /*file*/, size_t /*filelen*/)
+		{
+			return 0;
+		}
+
+		addr_t Construct(const void* file, size_t filelen)
+		{
+			if ( filelen < sizeof(Header) ) { return 0; }
+			const Header* header = (const Header*) file;
+
+			if ( !(header->magic[0] == 0x7F && header->magic[1] == 'E' &&
+                   header->magic[2] == 'L'  && header->magic[3] == 'F'  ) )
+			{
+				return 0;
+			}
+
+			switch ( header->fileclass )
+			{
+				case CLASS32:
+					return Construct32(file, filelen);
+				case CLASS64:
+					return Construct64(file, filelen);
+				default:
+					return 0;
+			}		
+		}
+	}
+}
+

sortix/elf.h

@@ -0,0 +1,102 @@
+/******************************************************************************
+
+	COPYRIGHT(C) JONAS 'SORTIE' TERMANSEN 2011.
+
+	This file is part of Sortix.
+
+	Sortix 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 3 of the License, or (at your option) any later
+	version.
+
+	Sortix 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 Sortix. If not, see <http://www.gnu.org/licenses/>.
+
+	elf.h
+	Constructs processes from ELF files.
+
+******************************************************************************/
+
+#ifndef SORTIX_ELF_H
+#define SORTIX_ELF_H
+
+namespace Sortix
+{
+	namespace ELF
+	{
+		struct Header
+		{
+			unsigned char magic[4];
+			unsigned char fileclass;
+			unsigned char dataencoding;
+			unsigned char version;
+			unsigned char padding[9];
+		};
+
+		const unsigned char CLASSNONE = 0;
+		const unsigned char CLASS32 = 1;
+		const unsigned char CLASS64 = 2;
+		const unsigned char DATA2LSB = 1;
+		const unsigned char DATA2MSB = 2;
+		const unsigned char CURRENTVERSION = 1;
+
+		struct Header32 : public Header
+		{
+			uint16_t type;
+			uint16_t machine;
+			uint32_t version;
+			uint32_t entry;
+			uint32_t programheaderoffset;
+			uint32_t sectionheaderoffset;
+			uint32_t flags;
+			uint16_t elfheadersize;
+			uint16_t programheaderentrysize;
+			uint16_t numprogramheaderentries;
+			uint16_t sectionheaderentrysize;
+			uint16_t numsectionheaderentries;
+			uint16_t sectionheaderstringindex;
+		};
+
+		struct SectionHeader32
+		{
+			uint32_t name;
+			uint32_t type;
+			uint32_t flags;
+			uint32_t addr;
+			uint32_t offset;
+			uint32_t size;
+			uint32_t link;
+			uint32_t info;
+			uint32_t addralign;
+			uint32_t entsize;
+		};
+
+		const uint32_t SHT_NULL = 0;
+		const uint32_t SHT_PROGBITS = 1;
+		const uint32_t SHT_SYMTAB = 2;
+		const uint32_t SHT_STRTAB = 3;
+		const uint32_t SHT_RELA = 4;
+		const uint32_t SHT_HASH = 5;
+		const uint32_t SHT_DYNAMIC = 6;
+		const uint32_t SHT_NOTE = 7;
+		const uint32_t SHT_NOBITS = 8;
+		const uint32_t SHT_REL = 9;
+		const uint32_t SHT_SHLIB = 10;
+		const uint32_t SHT_DYNSYM = 11;
+		const uint32_t SHT_LOPROC = 0x70000000;
+		const uint32_t SHT_HIPROC = 0x7fffffff;
+		const uint32_t SHT_LOUSER = 0x80000000;
+		const uint32_t SHT_HIUSER = 0xffffffff;
+
+		// Reads the elf file into the current address space and returns the
+		// entry address of the program, or 0 upon failure.
+		addr_t Construct(const void* file, size_t filelen);
+	}
+}
+
+#endif