0515111314
This fixes issues where it did not fit into the first few MiB, or that GRUB loaded it someplace weird. The kernel heap is now also protected against growing into the ramdisk and the kernel stack.
132 lines
3.7 KiB
C++
132 lines
3.7 KiB
C++
/******************************************************************************
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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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initrd.cpp
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Declares the structure of the Sortix ramdisk.
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******************************************************************************/
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#include "platform.h"
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#include "initrd.h"
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#include <libmaxsi/memory.h>
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#include <libmaxsi/string.h>
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#include "syscall.h"
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#include "memorymanagement.h"
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#include "log.h" // DEBUG
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using namespace Maxsi;
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namespace Sortix
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{
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namespace InitRD
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{
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byte* initrd;
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size_t initrdsize;
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#ifdef JSSORTIX
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// JSVM never tells JSSortix how big the initrd is!
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const bool CHECK_CHECKSUM = false;
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#else
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const bool CHECK_CHECKSUM = true;
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#endif
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size_t GetNumFiles()
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{
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Header* header = (Header*) initrd;
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return header->numfiles;
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}
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const char* GetFilename(size_t index)
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{
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Header* header = (Header*) initrd;
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if ( index >= header->numfiles ) { return NULL; }
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FileHeader* fhtbl = (FileHeader*) (initrd + sizeof(Header));
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FileHeader* fileheader = &(fhtbl[index]);
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return fileheader->name;
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}
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uint8_t ContinueChecksum(uint8_t checksum, const void* p, size_t size)
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{
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const uint8_t* buffer = (const uint8_t*) p;
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while ( size-- )
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{
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checksum += *buffer++;
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}
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return checksum;
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}
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void CheckSum()
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{
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Trailer* trailer = (Trailer*) (initrd + initrdsize - sizeof(Trailer));
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uint8_t checksum = ContinueChecksum(0, initrd, initrdsize - sizeof(Trailer));
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if ( trailer->sum != checksum )
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{
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PanicF("InitRD Checksum failed: the ramdisk may have been "
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"corrupted by the bootloader: Got %u instead of %u "
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"when checking the ramdisk at 0x%p + 0x%zx bytes\n",
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checksum, trailer->sum, initrd, initrdsize);
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}
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}
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void Init(addr_t phys, size_t size)
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{
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// First up, map the initrd onto the kernel's address space.
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addr_t virt = Memory::GetInitRD();
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size_t amount = 0;
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while ( amount < size )
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{
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if ( !Memory::MapKernel(phys + amount, virt + amount) )
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{
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Panic("Unable to map the init ramdisk into virtual memory");
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}
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amount += 0x1000UL;
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}
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Memory::Flush();
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initrd = (byte*) virt;
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initrdsize = size;
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if ( size < sizeof(Header) ) { PanicF("initrd.cpp: initrd is too small"); }
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Header* header = (Header*) initrd;
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if ( String::Compare(header->magic, "sortix-initrd-1") != 0 ) { PanicF("initrd.cpp: invalid magic value in the initrd"); }
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size_t sizeneeded = sizeof(Header) + header->numfiles * sizeof(FileHeader);
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if ( size < sizeneeded ) { PanicF("initrd.cpp: initrd is too small"); }
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// TODO: We need to do more validation here!
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if ( CHECK_CHECKSUM ) { CheckSum(); }
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}
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byte* Open(const char* filepath, size_t* size)
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{
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Header* header = (Header*) initrd;
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FileHeader* fhtbl = (FileHeader*) (initrd + sizeof(Header));
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for ( uint32_t i = 0; i < header->numfiles; i++ )
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{
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FileHeader* fileheader = &(fhtbl[i]);
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if ( String::Compare(filepath, fileheader->name) != 0 ) { continue; }
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*size = fileheader->size;
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return initrd + fileheader->offset;
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}
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return NULL;
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}
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}
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}
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