1
0
Fork 0
mirror of https://gitlab.com/sortix/sortix.git synced 2023-02-13 20:55:38 -05:00
sortix--sortix/kernel/elf.cpp
Philippe Michaud-Boudreault 4890297611 Optimize is_power_of_two.
2016-11-06 17:42:13 +01:00

321 lines
9.5 KiB
C++

/*
* Copyright (c) 2011, 2012, 2013, 2014 Jonas 'Sortie' Termansen.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
* elf.cpp
* Load a program in the Executable and Linkable Format into this process.
*/
#include <sys/types.h>
#include <assert.h>
#include <elf.h>
#include <endian.h>
#include <errno.h>
#include <stddef.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <system-elf.h>
#include <__/wordsize.h>
#include <sortix/mman.h>
#include <sortix/kernel/elf.h>
#include <sortix/kernel/kernel.h>
#include <sortix/kernel/memorymanagement.h>
#include <sortix/kernel/process.h>
#include <sortix/kernel/segment.h>
namespace Sortix {
namespace ELF {
static bool is_power_of_two(uintptr_t value)
{
return value && !(value & (value - 1));
}
uintptr_t Load(const void* file_ptr, size_t file_size, Auxiliary* aux)
{
memset(aux, 0, sizeof(*aux));
Process* process = CurrentProcess();
uintptr_t userspace_addr;
size_t userspace_size;
Memory::GetUserVirtualArea(&userspace_addr, &userspace_size);
uintptr_t userspace_end = userspace_addr + userspace_size;
const unsigned char* file = (const unsigned char*) file_ptr;
if ( file_size < EI_NIDENT )
return errno = ENOEXEC, 0;
if ( memcmp(file, ELFMAG, SELFMAG) != 0 )
return errno = ENOEXEC, 0;
#if __WORDSIZE == 32
if ( file[EI_CLASS] != ELFCLASS32 )
return errno = EINVAL, 0;
#elif __WORDSIZE == 64
if ( file[EI_CLASS] != ELFCLASS64 )
return errno = EINVAL, 0;
#else
#error "You need to add support for your elf class."
#endif
#if BYTE_ORDER == LITTLE_ENDIAN
if ( file[EI_DATA] != ELFDATA2LSB )
return errno = EINVAL, 0;
#elif BYTE_ORDER == BIG_ENDIAN
if ( file[EI_DATA] != ELFDATA2MSB )
return errno = EINVAL, 0;
#else
#error "You need to add support for your endian."
#endif
if ( file[EI_VERSION] != EV_CURRENT )
return errno = EINVAL, 0;
if ( file[EI_OSABI] != ELFOSABI_SORTIX )
return errno = EINVAL, 0;
if ( file[EI_ABIVERSION] != 0 )
return errno = EINVAL, 0;
if ( file_size < sizeof(Elf_Ehdr) )
return errno = EINVAL, 0;
if ( (uintptr_t) file & (alignof(Elf_Ehdr) - 1) )
return errno = EINVAL, 0;
const Elf_Ehdr* header = (const Elf_Ehdr*) file;
if ( header->e_ehsize < sizeof(Elf_Ehdr) )
return errno = EINVAL, 0;
if ( file_size < header->e_ehsize )
return errno = EINVAL, 0;
#if defined(__i386__)
if ( header->e_machine != EM_386 )
return errno = EINVAL, 0;
#elif defined(__x86_64__)
if ( header->e_machine != EM_X86_64 )
return errno = EINVAL, 0;
#else
#error "Please recognize your processor in e_machine."
#endif
if ( header->e_type != ET_EXEC )
return errno = EINVAL, 0;
if ( header->e_entry < userspace_addr || userspace_end <= header->e_entry )
return errno = EINVAL, 0;
if ( file_size < header->e_phoff )
return errno = EINVAL, 0;
if ( file_size < header->e_shoff )
return errno = EINVAL, 0;
if ( header->e_phentsize < sizeof(Elf_Phdr) )
return errno = EINVAL, 0;
if ( header->e_shentsize < sizeof(Elf_Shdr) )
return errno = EINVAL, 0;
process->ResetForExecute();
if ( header->e_phnum == (Elf_Half) -1 )
return errno = EINVAL, 0;
if ( header->e_shnum == (Elf_Half) -1 )
return errno = EINVAL, 0;
for ( Elf32_Half i = 0; i < header->e_phnum; i++ )
{
size_t max_phs = (file_size - header->e_phoff) / header->e_phentsize;
if ( max_phs <= i )
return errno = EINVAL, 0;
size_t pheader_offset = header->e_phoff + i * header->e_phentsize;
if ( (uintptr_t) (file + pheader_offset) & (alignof(Elf_Phdr) - 1) )
return errno = EINVAL, 0;
Elf_Phdr* pheader = (Elf_Phdr*) (file + pheader_offset);
switch ( pheader->p_type )
{
case PT_TLS: break;
case PT_NOTE: break;
case PT_LOAD: break;
default: continue;
};
if ( !is_power_of_two(pheader->p_align) )
return errno = EINVAL, 0;
if ( file_size < pheader->p_offset )
return errno = EINVAL, 0;
if ( file_size - pheader->p_offset < pheader->p_filesz )
return errno = EINVAL, 0;
if ( pheader->p_type == PT_TLS )
{
if ( pheader->p_memsz < pheader->p_filesz )
return errno = EINVAL, 0;
aux->tls_file_offset = pheader->p_offset;
aux->tls_file_size = pheader->p_filesz;
aux->tls_mem_size = pheader->p_memsz;
aux->tls_mem_align = pheader->p_align;
continue;
}
if ( pheader->p_type == PT_NOTE )
{
size_t notes_offset = 0;
while ( notes_offset < pheader->p_filesz )
{
size_t available = pheader->p_filesz - notes_offset;
size_t note_header_size = 3 * sizeof(uint32_t);
if ( available < note_header_size )
return errno = EINVAL, 0;
available -= note_header_size;
size_t file_offset = pheader->p_offset + notes_offset;
if ( ((uintptr_t) file + file_offset) & (alignof(uint32_t) - 1) )
return errno = EINVAL, 0;
const unsigned char* note = file + file_offset;
uint32_t* note_header = (uint32_t*) note;
uint32_t namesz = note_header[0];
uint32_t descsz = note_header[1];
uint32_t type = note_header[2];
uint32_t namesz_aligned = -(-namesz & ~(sizeof(uint32_t) - 1));
uint32_t descsz_aligned = -(-descsz & ~(sizeof(uint32_t) - 1));
if ( available < namesz_aligned )
return errno = EINVAL, 0;
available -= namesz_aligned;
if ( available < descsz_aligned )
return errno = EINVAL, 0;
available -= descsz_aligned;
(void) available;
notes_offset += note_header_size + namesz_aligned + descsz_aligned;
const char* name = (const char*) (note + note_header_size);
if ( strnlen(name, namesz_aligned) == namesz_aligned )
return errno = EINVAL, 0;
const unsigned char* desc = note + note_header_size + namesz_aligned;
const uint32_t* desc_32bits = (const uint32_t*) desc;
if ( strcmp(name, ELF_NOTE_SORTIX) == 0 )
{
if ( type == ELF_NOTE_SORTIX_UTHREAD_SIZE )
{
if ( descsz_aligned != 2 * sizeof(size_t) )
return errno = EINVAL, 0;
#if __WORDSIZE == 32
aux->uthread_size = desc_32bits[0];
aux->uthread_align = desc_32bits[1];
#elif __WORDSIZE == 64 && BYTE_ORDER == LITTLE_ENDIAN
aux->uthread_size = (uint64_t) desc_32bits[0] << 0 |
(uint64_t) desc_32bits[1] << 32;
aux->uthread_align = (uint64_t) desc_32bits[2] << 0 |
(uint64_t) desc_32bits[3] << 32;
#elif __WORDSIZE == 64 && BYTE_ORDER == BIG_ENDIAN
aux->uthread_size = (uint64_t) desc_32bits[1] << 0 |
(uint64_t) desc_32bits[0] << 32;
aux->uthread_align = (uint64_t) desc_32bits[3] << 0 |
(uint64_t) desc_32bits[2] << 32;
#else
#error "You need to correctly read the uthread note"
#endif
if ( !is_power_of_two(aux->uthread_align) )
return errno = EINVAL, 0;
}
}
}
continue;
}
if ( pheader->p_type == PT_LOAD )
{
if ( pheader->p_memsz < pheader->p_filesz )
return errno = EINVAL, 0;
if ( pheader->p_filesz &&
pheader->p_vaddr % pheader->p_align !=
pheader->p_offset % pheader->p_align )
return errno = EINVAL, 0;
int kprot = PROT_KWRITE | PROT_FORK;
int prot = PROT_FORK;
if ( pheader->p_flags & PF_X )
prot |= PROT_EXEC;
if ( pheader->p_flags & PF_R )
prot |= PROT_READ | PROT_KREAD;
if ( pheader->p_flags & PF_W )
prot |= PROT_WRITE | PROT_KWRITE;
if ( pheader->p_vaddr < userspace_addr )
return errno = EINVAL, 0;
if ( userspace_end < pheader->p_vaddr )
return errno = EINVAL, 0;
if ( userspace_end - pheader->p_vaddr < pheader->p_memsz )
return errno = EINVAL, 0;
uintptr_t map_start = Page::AlignDown(pheader->p_vaddr);
uintptr_t map_end = Page::AlignUp(pheader->p_vaddr + pheader->p_memsz);
size_t map_size = map_end - map_start;
struct segment segment;
segment.addr = map_start;
segment.size = map_size;
segment.prot = kprot;
assert(IsUserspaceSegment(&segment));
kthread_mutex_lock(&process->segment_write_lock);
kthread_mutex_lock(&process->segment_lock);
if ( IsSegmentOverlapping(process, &segment) )
{
kthread_mutex_unlock(&process->segment_lock);
kthread_mutex_unlock(&process->segment_write_lock);
return errno = EINVAL, 0;
}
if ( !Memory::MapRange(segment.addr, segment.size, kprot, PAGE_USAGE_USER_SPACE) )
{
kthread_mutex_unlock(&process->segment_lock);
kthread_mutex_unlock(&process->segment_write_lock);
return errno = EINVAL, 0;
}
if ( !AddSegment(process, &segment) )
{
Memory::UnmapRange(segment.addr, segment.size, PAGE_USAGE_USER_SPACE);
kthread_mutex_unlock(&process->segment_lock);
kthread_mutex_unlock(&process->segment_write_lock);
return errno = EINVAL, 0;
}
memset((void*) segment.addr, 0, segment.size);
memcpy((void*) pheader->p_vaddr, file + pheader->p_offset, pheader->p_filesz);
Memory::ProtectMemory(CurrentProcess(), segment.addr, segment.size, prot);
kthread_mutex_unlock(&process->segment_lock);
kthread_mutex_unlock(&process->segment_write_lock);
}
}
return header->e_entry;
}
} // namespace ELF
} // namespace Sortix