mirror of
https://gitlab.com/sortix/sortix.git
synced 2023-02-13 20:55:38 -05:00
407 lines
12 KiB
C++
407 lines
12 KiB
C++
/*******************************************************************************
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Copyright(C) Jonas 'Sortie' Termansen 2011, 2012, 2013, 2014.
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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 with
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Sortix. If not, see <http://www.gnu.org/licenses/>.
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elf.cpp
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Load a program in the Executable and Linkable Format into this process.
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*******************************************************************************/
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#include <sys/types.h>
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#include <assert.h>
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#include <elf.h>
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#include <endian.h>
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#include <errno.h>
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#include <stddef.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include <string.h>
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#include <system-elf.h>
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#include <__/wordsize.h>
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#include <sortix/mman.h>
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#include <sortix/kernel/elf.h>
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#include <sortix/kernel/kernel.h>
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#include <sortix/kernel/memorymanagement.h>
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#include <sortix/kernel/process.h>
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#include <sortix/kernel/segment.h>
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#include <sortix/kernel/symbol.h>
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namespace Sortix {
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namespace ELF {
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static bool is_power_of_two(uintptr_t value)
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{
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for ( uintptr_t i = 0; i < sizeof(uintptr_t) * 8; i++ )
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if ( (uintptr_t) 1 << i == value )
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return true;
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return false;
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}
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uintptr_t Load(const void* file_ptr, size_t file_size, Auxiliary* aux)
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{
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memset(aux, 0, sizeof(*aux));
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Process* process = CurrentProcess();
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uintptr_t userspace_addr;
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size_t userspace_size;
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Memory::GetUserVirtualArea(&userspace_addr, &userspace_size);
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uintptr_t userspace_end = userspace_addr + userspace_size;
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const unsigned char* file = (const unsigned char*) file_ptr;
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if ( file_size < EI_NIDENT )
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return errno = ENOEXEC, 0;
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if ( memcmp(file, ELFMAG, SELFMAG) != 0 )
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return errno = ENOEXEC, 0;
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#if __WORDSIZE == 32
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if ( file[EI_CLASS] != ELFCLASS32 )
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return errno = EINVAL, 0;
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#elif __WORDSIZE == 64
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if ( file[EI_CLASS] != ELFCLASS64 )
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return errno = EINVAL, 0;
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#else
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#error "You need to add support for your elf class."
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#endif
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#if BYTE_ORDER == LITTLE_ENDIAN
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if ( file[EI_DATA] != ELFDATA2LSB )
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return errno = EINVAL, 0;
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#elif BYTE_ORDER == BIG_ENDIAN
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if ( file[EI_DATA] != ELFDATA2MSB )
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return errno = EINVAL, 0;
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#else
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#error "You need to add support for your endian."
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#endif
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if ( file[EI_VERSION] != EV_CURRENT )
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return errno = EINVAL, 0;
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if ( file[EI_OSABI] != ELFOSABI_SORTIX )
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return errno = EINVAL, 0;
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if ( file[EI_ABIVERSION] != 0 )
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return errno = EINVAL, 0;
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if ( file_size < sizeof(Elf_Ehdr) )
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return errno = EINVAL, 0;
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if ( (uintptr_t) file & (alignof(Elf_Ehdr) - 1) )
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return errno = EINVAL, 0;
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const Elf_Ehdr* header = (const Elf_Ehdr*) file;
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if ( header->e_ehsize < sizeof(Elf_Ehdr) )
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return errno = EINVAL, 0;
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if ( file_size < header->e_ehsize )
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return errno = EINVAL, 0;
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#if defined(__i386__)
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if ( header->e_machine != EM_386 )
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return errno = EINVAL, 0;
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#elif defined(__x86_64__)
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if ( header->e_machine != EM_X86_64 )
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return errno = EINVAL, 0;
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#else
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#error "Please recognize your processor in e_machine."
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#endif
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if ( header->e_type != ET_EXEC )
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return errno = EINVAL, 0;
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if ( header->e_entry == 0 )
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return errno = EINVAL, 0;
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if ( file_size < header->e_phoff )
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return errno = EINVAL, 0;
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if ( file_size < header->e_shoff )
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return errno = EINVAL, 0;
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if ( header->e_phentsize < sizeof(Elf_Phdr) )
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return errno = EINVAL, 0;
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if ( header->e_shentsize < sizeof(Elf_Shdr) )
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return errno = EINVAL, 0;
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process->ResetForExecute();
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if ( header->e_phnum == (Elf_Half) -1 )
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return errno = EINVAL, 0;
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if ( header->e_shnum == (Elf_Half) -1 )
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return errno = EINVAL, 0;
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for ( Elf32_Half i = 0; i < header->e_phnum; i++ )
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{
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size_t max_phs = (file_size - header->e_phoff) / header->e_phentsize;
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if ( max_phs <= i )
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return errno = EINVAL, 0;
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size_t pheader_offset = header->e_phoff + i * header->e_phentsize;
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if ( (uintptr_t) (file + pheader_offset) & (alignof(Elf_Phdr) - 1) )
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return errno = EINVAL, 0;
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Elf_Phdr* pheader = (Elf_Phdr*) (file + pheader_offset);
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switch ( pheader->p_type )
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{
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case PT_TLS: break;
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case PT_NOTE: break;
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case PT_LOAD: break;
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default: continue;
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};
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if ( !is_power_of_two(pheader->p_align) )
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return errno = EINVAL, 0;
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if ( file_size < pheader->p_offset )
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return errno = EINVAL, 0;
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if ( file_size - pheader->p_offset < pheader->p_filesz )
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return errno = EINVAL, 0;
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if ( pheader->p_type == PT_TLS )
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{
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if ( pheader->p_memsz < pheader->p_filesz )
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return errno = EINVAL, 0;
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aux->tls_file_offset = pheader->p_offset;
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aux->tls_file_size = pheader->p_filesz;
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aux->tls_mem_size = pheader->p_memsz;
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aux->tls_mem_align = pheader->p_align;
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continue;
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}
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if ( pheader->p_type == PT_NOTE )
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{
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size_t notes_offset = 0;
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while ( notes_offset < pheader->p_filesz )
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{
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size_t available = pheader->p_filesz - notes_offset;
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size_t note_header_size = 3 * sizeof(uint32_t);
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if ( available < note_header_size )
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return errno = EINVAL, 0;
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available -= note_header_size;
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size_t file_offset = pheader->p_offset + notes_offset;
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if ( ((uintptr_t) file + file_offset) & (alignof(uint32_t) - 1) )
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return errno = EINVAL, 0;
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const unsigned char* note = file + file_offset;
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uint32_t* note_header = (uint32_t*) note;
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uint32_t namesz = note_header[0];
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uint32_t descsz = note_header[1];
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uint32_t type = note_header[2];
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uint32_t namesz_aligned = -(-namesz & ~(sizeof(uint32_t) - 1));
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uint32_t descsz_aligned = -(-descsz & ~(sizeof(uint32_t) - 1));
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if ( available < namesz_aligned )
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return errno = EINVAL, 0;
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available -= namesz_aligned;
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if ( available < descsz_aligned )
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return errno = EINVAL, 0;
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available -= descsz_aligned;
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notes_offset += note_header_size + namesz_aligned + descsz_aligned;
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const char* name = (const char*) (note + note_header_size);
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if ( strnlen(name, namesz_aligned) == namesz_aligned )
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return errno = EINVAL, 0;
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const unsigned char* desc = note + note_header_size + namesz_aligned;
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const uint32_t* desc_32bits = (const uint32_t*) desc;
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if ( strcmp(name, ELF_NOTE_SORTIX) == 0 )
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{
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if ( type == ELF_NOTE_SORTIX_UTHREAD_SIZE )
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{
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if ( descsz_aligned != 2 * sizeof(size_t) )
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return errno = EINVAL, 0;
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#if __WORDSIZE == 32
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aux->uthread_size = desc_32bits[0];
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aux->uthread_align = desc_32bits[1];
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#elif __WORDSIZE == 64 && BYTE_ORDER == LITTLE_ENDIAN
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aux->uthread_size = (uint64_t) desc_32bits[0] << 0 |
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(uint64_t) desc_32bits[1] << 32;
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aux->uthread_align = (uint64_t) desc_32bits[2] << 0 |
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(uint64_t) desc_32bits[3] << 32;
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#elif __WORDSIZE == 64 && BYTE_ORDER == BIG_ENDIAN
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aux->uthread_size = (uint64_t) desc_32bits[1] << 0 |
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(uint64_t) desc_32bits[0] << 32;
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aux->uthread_align = (uint64_t) desc_32bits[3] << 0 |
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(uint64_t) desc_32bits[2] << 32;
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#else
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#error "You need to correctly read the uthread note"
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#endif
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if ( !is_power_of_two(aux->uthread_align) )
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return errno = EINVAL, 0;
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}
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}
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}
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continue;
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}
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if ( pheader->p_type == PT_LOAD )
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{
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if ( pheader->p_memsz < pheader->p_filesz )
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return errno = EINVAL, 0;
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if ( pheader->p_filesz &&
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pheader->p_vaddr % pheader->p_align !=
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pheader->p_offset % pheader->p_align )
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return errno = EINVAL, 0;
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int prot = PROT_FORK | PROT_KREAD | PROT_KWRITE;
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if ( pheader->p_flags & PF_X )
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prot |= PROT_EXEC;
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if ( pheader->p_flags & PF_R )
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prot |= PROT_READ;
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if ( pheader->p_flags & PF_W )
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prot |= PROT_WRITE;
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if ( pheader->p_vaddr < userspace_addr )
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return errno = EINVAL, 0;
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if ( userspace_end < pheader->p_vaddr )
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return errno = EINVAL, 0;
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if ( userspace_end - pheader->p_vaddr < pheader->p_memsz )
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return errno = EINVAL, 0;
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uintptr_t map_start = Page::AlignDown(pheader->p_vaddr);
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uintptr_t map_end = Page::AlignUp(pheader->p_vaddr + pheader->p_memsz);
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size_t map_size = map_end - map_start;
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struct segment segment;
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segment.addr = map_start;
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segment.size = map_size;
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segment.prot = prot;
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assert(IsUserspaceSegment(&segment));
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kthread_mutex_lock(&process->segment_write_lock);
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kthread_mutex_lock(&process->segment_lock);
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if ( IsSegmentOverlapping(process, &segment) )
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{
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kthread_mutex_unlock(&process->segment_lock);
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kthread_mutex_unlock(&process->segment_write_lock);
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return errno = EINVAL, 0;
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}
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if ( !Memory::MapRange(segment.addr, segment.size, prot, PAGE_USAGE_USER_SPACE) )
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{
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kthread_mutex_unlock(&process->segment_lock);
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kthread_mutex_unlock(&process->segment_write_lock);
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return errno = EINVAL, 0;
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}
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if ( !AddSegment(process, &segment) )
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{
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Memory::UnmapRange(segment.addr, segment.size, PAGE_USAGE_USER_SPACE);
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kthread_mutex_unlock(&process->segment_lock);
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kthread_mutex_unlock(&process->segment_write_lock);
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return errno = EINVAL, 0;
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}
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kthread_mutex_unlock(&process->segment_lock);
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kthread_mutex_unlock(&process->segment_write_lock);
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memset((void*) segment.addr, 0, segment.size);
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memcpy((void*) pheader->p_vaddr, file + pheader->p_offset, pheader->p_filesz);
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}
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}
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// SECURITY: TODO: Insecure.
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Elf_Shdr* section_string_table_section = (Elf_Shdr*) (file + header->e_shoff + header->e_shstrndx * header->e_shentsize);
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const char* section_string_table = (const char*) (file + section_string_table_section->sh_offset);
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//size_t section_string_table_size = section_string_table_section->sh_size;
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const char* string_table = NULL;
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size_t string_table_size = 0;
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for ( Elf32_Half i = 0; i < header->e_shnum; i++ )
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{
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size_t max_shs = (file_size - header->e_shoff) / header->e_shentsize;
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if ( max_shs <= i )
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return errno = EINVAL, 0;
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size_t sheader_offset = header->e_shoff + i * header->e_shentsize;
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if ( (uintptr_t) (file + sheader_offset) & (alignof(Elf_Shdr) - 1) )
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return errno = EINVAL, 0;
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Elf_Shdr* sheader = (Elf_Shdr*) (file + sheader_offset);
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// SECURITY: TODO: Insecure.
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const char* section_name = section_string_table + sheader->sh_name;
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if ( !strcmp(section_name, ".strtab") )
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{
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// SECURITY: TODO: Insecure.
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string_table = (const char*) (file + sheader->sh_offset);
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string_table_size = sheader->sh_size;
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}
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}
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for ( Elf32_Half i = 0; i < header->e_shnum; i++ )
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{
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size_t sheader_offset = header->e_shoff + i * header->e_shentsize;
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Elf_Shdr* sheader = (Elf_Shdr*) (file + sheader_offset);
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// SECURITY: TODO: Insecure.
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const char* section_name = section_string_table + sheader->sh_name;
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if ( !strcmp(section_name, ".symtab") )
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{
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if ( process->symbol_table )
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continue;
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// SECURITY: TODO: Insecure.
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Elf_Sym* symbols = (Elf_Sym*) (file + sheader->sh_offset);
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size_t symbols_length = sheader->sh_size / sizeof(Elf_Sym);
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if ( symbols_length == 0 )
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continue;
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symbols++;
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symbols_length--;
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char* string_table_copy = new char[string_table_size];
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if ( !string_table_copy )
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continue;
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memcpy(string_table_copy, string_table, string_table_size);
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Symbol* symbols_copy = new Symbol[symbols_length];
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if ( !symbols_copy )
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{
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delete[] string_table_copy;
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continue;
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}
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for ( size_t i = 0; i < symbols_length; i++ )
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{
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memset(&symbols_copy[i], 0, sizeof(symbols_copy[i]));
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symbols_copy[i].address = symbols[i].st_value;
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symbols_copy[i].size = symbols[i].st_size;
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// SECURITY: TODO: Insecure.
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symbols_copy[i].name = string_table_copy + symbols[i].st_name;
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}
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process->string_table = string_table_copy;
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process->string_table_length = string_table_size;
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process->symbol_table = symbols_copy;
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process->symbol_table_length = symbols_length;
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}
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}
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return header->e_entry;
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}
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} // namespace ELF
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} // namespace Sortix
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