1 use core::{ 2 cmp::{max, min}, 3 fmt::Debug, 4 intrinsics::{likely, unlikely}, 5 ops::Range, 6 }; 7 8 use alloc::vec::Vec; 9 use elf::{ 10 abi::{PT_GNU_PROPERTY, PT_INTERP}, 11 endian::AnyEndian, 12 file::FileHeader, 13 segment::ProgramHeader, 14 }; 15 use system_error::SystemError; 16 17 use crate::{ 18 arch::{CurrentElfArch, MMArch}, 19 driver::base::block::SeekFrom, 20 filesystem::vfs::file::File, 21 kerror, 22 libs::align::page_align_up, 23 mm::{ 24 allocator::page_frame::{PageFrameCount, VirtPageFrame}, 25 syscall::{MapFlags, ProtFlags}, 26 ucontext::InnerAddressSpace, 27 MemoryManagementArch, VirtAddr, 28 }, 29 process::{ 30 abi::AtType, 31 exec::{BinaryLoader, BinaryLoaderResult, ExecError, ExecLoadMode, ExecParam}, 32 ProcessFlags, ProcessManager, 33 }, 34 syscall::user_access::{clear_user, copy_to_user}, 35 }; 36 37 use super::rwlock::RwLockWriteGuard; 38 39 // 存放跟架构相关的Elf属性， 40 pub trait ElfArch: Clone + Copy + Debug { 41 const ELF_ET_DYN_BASE: usize; 42 const ELF_PAGE_SIZE: usize; 43 } 44 45 #[derive(Debug)] 46 pub struct ElfLoader; 47 48 pub const ELF_LOADER: ElfLoader = ElfLoader::new(); 49 50 impl ElfLoader { 51 /// 读取文件的缓冲区大小 52 pub const FILE_READ_BUF_SIZE: usize = 512 * 1024; 53 new() -> Self54 pub const fn new() -> Self { 55 Self 56 } 57 inner_probe_common( &self, param: &ExecParam, ehdr: &FileHeader<AnyEndian>, ) -> Result<(), ExecError>58 fn inner_probe_common( 59 &self, 60 param: &ExecParam, 61 ehdr: &FileHeader<AnyEndian>, 62 ) -> Result<(), ExecError> { 63 // 只支持 64 位的 ELF 文件 64 if ehdr.class != elf::file::Class::ELF64 { 65 return Err(ExecError::WrongArchitecture); 66 } 67 68 // 判断是否以可执行文件的形式加载 69 if param.load_mode() == ExecLoadMode::Exec { 70 // 检查文件类型是否为可执行文件 71 if ElfType::from(ehdr.e_type) != ElfType::Executable 72 && ElfType::from(ehdr.e_type) != ElfType::DSO 73 { 74 return Err(ExecError::NotExecutable); 75 } 76 } else { 77 return Err(ExecError::NotSupported); 78 } 79 80 return Ok(()); 81 } 82 83 #[cfg(target_arch = "x86_64")] probe_x86_64( &self, param: &ExecParam, ehdr: &FileHeader<AnyEndian>, ) -> Result<(), ExecError>84 pub fn probe_x86_64( 85 &self, 86 param: &ExecParam, 87 ehdr: &FileHeader<AnyEndian>, 88 ) -> Result<(), ExecError> { 89 // 判断架构是否匹配 90 if ElfMachine::from(ehdr.e_machine) != ElfMachine::X86_64 { 91 return Err(ExecError::WrongArchitecture); 92 } 93 return self.inner_probe_common(param, ehdr); 94 } 95 96 #[cfg(target_arch = "riscv64")] probe_riscv( &self, param: &ExecParam, ehdr: &FileHeader<AnyEndian>, ) -> Result<(), ExecError>97 pub fn probe_riscv( 98 &self, 99 param: &ExecParam, 100 ehdr: &FileHeader<AnyEndian>, 101 ) -> Result<(), ExecError> { 102 // 判断架构是否匹配 103 if ElfMachine::from(ehdr.e_machine) != ElfMachine::RiscV { 104 return Err(ExecError::WrongArchitecture); 105 } 106 return self.inner_probe_common(param, ehdr); 107 } 108 109 /// 设置用户堆空间，映射[start, end)区间的虚拟地址，并把brk指针指向end 110 /// 111 /// ## 参数 112 /// 113 /// - `user_vm_guard` - 用户虚拟地址空间 114 /// - `start` - 本次映射的起始地址 115 /// - `end` - 本次映射的结束地址（不包含） 116 /// - `prot_flags` - 本次映射的权限 set_elf_brk( &self, user_vm_guard: &mut RwLockWriteGuard<'_, InnerAddressSpace>, start: VirtAddr, end: VirtAddr, prot_flags: ProtFlags, ) -> Result<(), ExecError>117 fn set_elf_brk( 118 &self, 119 user_vm_guard: &mut RwLockWriteGuard<'_, InnerAddressSpace>, 120 start: VirtAddr, 121 end: VirtAddr, 122 prot_flags: ProtFlags, 123 ) -> Result<(), ExecError> { 124 let start = self.elf_page_start(start); 125 let end = self.elf_page_align_up(end); 126 127 if end > start { 128 let r = user_vm_guard.map_anonymous( 129 start, 130 end - start, 131 prot_flags, 132 MapFlags::MAP_ANONYMOUS | MapFlags::MAP_FIXED_NOREPLACE, 133 false, 134 ); 135 if r.is_err() { 136 kerror!("set_elf_brk: map_anonymous failed, err={:?}", r); 137 return Err(ExecError::OutOfMemory); 138 } 139 } 140 user_vm_guard.elf_brk_start = end; 141 user_vm_guard.elf_brk = end; 142 return Ok(()); 143 } 144 145 /// 计算addr在ELF PAGE内的偏移 elf_page_offset(&self, addr: VirtAddr) -> usize146 fn elf_page_offset(&self, addr: VirtAddr) -> usize { 147 addr.data() & (CurrentElfArch::ELF_PAGE_SIZE - 1) 148 } 149 elf_page_start(&self, addr: VirtAddr) -> VirtAddr150 fn elf_page_start(&self, addr: VirtAddr) -> VirtAddr { 151 VirtAddr::new(addr.data() & (!(CurrentElfArch::ELF_PAGE_SIZE - 1))) 152 } 153 elf_page_align_up(&self, addr: VirtAddr) -> VirtAddr154 fn elf_page_align_up(&self, addr: VirtAddr) -> VirtAddr { 155 VirtAddr::new( 156 (addr.data() + CurrentElfArch::ELF_PAGE_SIZE - 1) 157 & (!(CurrentElfArch::ELF_PAGE_SIZE - 1)), 158 ) 159 } 160 161 /// 根据ELF的p_flags生成对应的ProtFlags make_prot(&self, p_flags: u32, _has_interpreter: bool, _is_interpreter: bool) -> ProtFlags162 fn make_prot(&self, p_flags: u32, _has_interpreter: bool, _is_interpreter: bool) -> ProtFlags { 163 let mut prot = ProtFlags::empty(); 164 if p_flags & elf::abi::PF_R != 0 { 165 prot |= ProtFlags::PROT_READ; 166 } 167 if p_flags & elf::abi::PF_W != 0 { 168 prot |= ProtFlags::PROT_WRITE; 169 } 170 if p_flags & elf::abi::PF_X != 0 { 171 prot |= ProtFlags::PROT_EXEC; 172 } 173 174 // todo: 增加与架构相关的处理 175 // ref: https://code.dragonos.org.cn/xref/linux-5.19.10/fs/binfmt_elf.c?r=&mo=22652&fi=824#572 176 177 return prot; 178 } 179 180 /// 加载ELF文件到用户空间 181 /// 182 /// 参考Linux的elf_map函数 183 /// https://code.dragonos.org.cn/xref/linux-5.19.10/fs/binfmt_elf.c?r=&mo=22652&fi=824#365 184 /// ## 参数 185 /// 186 /// - `user_vm_guard`：用户空间地址空间 187 /// - `param`：执行参数 188 /// - `phent`：ELF文件的ProgramHeader 189 /// - `addr_to_map`：当前段应该被加载到的内存地址 190 /// - `prot`：保护标志 191 /// - `map_flags`：映射标志 192 /// - `total_size`：ELF文件的总大小 193 /// 194 /// ## 返回值 195 /// 196 /// - `Ok((VirtAddr, bool))`：如果成功加载，则bool值为true，否则为false. VirtAddr为加载的地址 load_elf_segment( &self, user_vm_guard: &mut RwLockWriteGuard<'_, InnerAddressSpace>, param: &mut ExecParam, phent: &ProgramHeader, mut addr_to_map: VirtAddr, prot: &ProtFlags, map_flags: &MapFlags, total_size: usize, ) -> Result<(VirtAddr, bool), SystemError>197 fn load_elf_segment( 198 &self, 199 user_vm_guard: &mut RwLockWriteGuard<'_, InnerAddressSpace>, 200 param: &mut ExecParam, 201 phent: &ProgramHeader, 202 mut addr_to_map: VirtAddr, 203 prot: &ProtFlags, 204 map_flags: &MapFlags, 205 total_size: usize, 206 ) -> Result<(VirtAddr, bool), SystemError> { 207 // kdebug!("load_elf_segment: addr_to_map={:?}", addr_to_map); 208 209 // 映射位置的偏移量（页内偏移） 210 let beginning_page_offset = self.elf_page_offset(addr_to_map); 211 addr_to_map = self.elf_page_start(addr_to_map); 212 // 计算要映射的内存的大小 213 let map_size = phent.p_filesz as usize + beginning_page_offset; 214 let map_size = self.elf_page_align_up(VirtAddr::new(map_size)).data(); 215 // 当前段在文件中的大小 216 let seg_in_file_size = phent.p_filesz as usize; 217 // 当前段在文件中的偏移量 218 let file_offset = phent.p_offset as usize; 219 220 // 如果当前段的大小为0，则直接返回. 221 // 段在文件中的大小为0,是合法的，但是段在内存中的大小不能为0 222 if map_size == 0 { 223 return Ok((addr_to_map, true)); 224 } 225 226 let map_err_handler = |err: SystemError| { 227 if err == SystemError::EEXIST { 228 kerror!( 229 "Pid: {:?}, elf segment at {:p} overlaps with existing mapping", 230 ProcessManager::current_pcb().pid(), 231 addr_to_map.as_ptr::<u8>() 232 ); 233 } 234 err 235 }; 236 // 由于后面需要把ELF文件的内容加载到内存，因此暂时把当前段的权限设置为可写 237 let tmp_prot = if !prot.contains(ProtFlags::PROT_WRITE) { 238 *prot | ProtFlags::PROT_WRITE 239 } else { 240 *prot 241 }; 242 243 // 映射到的虚拟地址。请注意，这个虚拟地址是user_vm_guard这个地址空间的虚拟地址。不一定是当前进程地址空间的 244 let map_addr: VirtAddr; 245 246 // total_size is the size of the ELF (interpreter) image. 247 // The _first_ mmap needs to know the full size, otherwise 248 // randomization might put this image into an overlapping 249 // position with the ELF binary image. (since size < total_size) 250 // So we first map the 'big' image - and unmap the remainder at 251 // the end. (which unmap is needed for ELF images with holes.) 252 if total_size != 0 { 253 let total_size = self.elf_page_align_up(VirtAddr::new(total_size)).data(); 254 255 // kdebug!("total_size={}", total_size); 256 257 map_addr = user_vm_guard 258 .map_anonymous(addr_to_map, total_size, tmp_prot, *map_flags, false) 259 .map_err(map_err_handler)? 260 .virt_address(); 261 // kdebug!("map ok: addr_to_map={:?}", addr_to_map); 262 263 let to_unmap = map_addr + map_size; 264 let to_unmap_size = total_size - map_size; 265 266 // kdebug!("to_unmap={:?}, to_unmap_size={}", to_unmap, to_unmap_size); 267 user_vm_guard.munmap( 268 VirtPageFrame::new(to_unmap), 269 PageFrameCount::from_bytes(to_unmap_size).unwrap(), 270 )?; 271 272 // 加载文件到内存 273 self.do_load_file( 274 map_addr + beginning_page_offset, 275 seg_in_file_size, 276 file_offset, 277 param, 278 )?; 279 if tmp_prot != *prot { 280 user_vm_guard.mprotect( 281 VirtPageFrame::new(map_addr), 282 PageFrameCount::from_bytes(page_align_up(map_size)).unwrap(), 283 *prot, 284 )?; 285 } 286 } else { 287 // kdebug!("total size = 0"); 288 289 map_addr = user_vm_guard 290 .map_anonymous(addr_to_map, map_size, tmp_prot, *map_flags, false)? 291 .virt_address(); 292 // kdebug!( 293 // "map ok: addr_to_map={:?}, map_addr={map_addr:?},beginning_page_offset={beginning_page_offset:?}", 294 // addr_to_map 295 // ); 296 297 // 加载文件到内存 298 self.do_load_file( 299 map_addr + beginning_page_offset, 300 seg_in_file_size, 301 file_offset, 302 param, 303 )?; 304 305 if tmp_prot != *prot { 306 user_vm_guard.mprotect( 307 VirtPageFrame::new(map_addr), 308 PageFrameCount::from_bytes(page_align_up(map_size)).unwrap(), 309 *prot, 310 )?; 311 } 312 } 313 // kdebug!("load_elf_segment OK: map_addr={:?}", map_addr); 314 return Ok((map_addr, true)); 315 } 316 317 /// 加载ELF文件到用户空间 318 /// 319 /// ## 参数 320 /// 321 /// - `vaddr`：要加载到的虚拟地址 322 /// - `size`：要加载的大小 323 /// - `offset_in_file`：在文件内的偏移量 324 /// - `param`：执行参数 do_load_file( &self, mut vaddr: VirtAddr, size: usize, offset_in_file: usize, param: &mut ExecParam, ) -> Result<(), SystemError>325 fn do_load_file( 326 &self, 327 mut vaddr: VirtAddr, 328 size: usize, 329 offset_in_file: usize, 330 param: &mut ExecParam, 331 ) -> Result<(), SystemError> { 332 let file = param.file_mut(); 333 if (file.metadata()?.size as usize) < offset_in_file + size { 334 return Err(SystemError::ENOEXEC); 335 } 336 let buf_size = min(size, Self::FILE_READ_BUF_SIZE); 337 let mut buf = vec![0u8; buf_size]; 338 339 let mut remain = size; 340 341 file.lseek(SeekFrom::SeekSet(offset_in_file as i64))?; 342 343 while remain > 0 { 344 let read_size = min(remain, buf_size); 345 file.read(read_size, &mut buf[..read_size])?; 346 // kdebug!("copy_to_user: vaddr={:?}, read_size = {read_size}", vaddr); 347 unsafe { 348 copy_to_user(vaddr, &buf[..read_size]).map_err(|_| SystemError::EFAULT)?; 349 } 350 351 vaddr += read_size; 352 remain -= read_size; 353 } 354 return Ok(()); 355 } 356 357 /// 我们需要显式的把数据段之后剩余的内存页都清零。 pad_zero(&self, elf_bss: VirtAddr) -> Result<(), SystemError>358 fn pad_zero(&self, elf_bss: VirtAddr) -> Result<(), SystemError> { 359 let nbyte = self.elf_page_offset(elf_bss); 360 if nbyte > 0 { 361 let nbyte = CurrentElfArch::ELF_PAGE_SIZE - nbyte; 362 unsafe { clear_user(elf_bss, nbyte).map_err(|_| SystemError::EFAULT) }?; 363 } 364 return Ok(()); 365 } 366 367 /// 创建auxv 368 /// 369 /// ## 参数 370 /// 371 /// - `param`：执行参数 372 /// - `entrypoint_vaddr`：程序入口地址 373 /// - `phdr_vaddr`：程序头表地址 374 /// - `elf_header`：ELF文件头 create_auxv( &self, param: &mut ExecParam, entrypoint_vaddr: VirtAddr, phdr_vaddr: Option<VirtAddr>, ehdr: &elf::file::FileHeader<AnyEndian>, ) -> Result<(), ExecError>375 fn create_auxv( 376 &self, 377 param: &mut ExecParam, 378 entrypoint_vaddr: VirtAddr, 379 phdr_vaddr: Option<VirtAddr>, 380 ehdr: &elf::file::FileHeader<AnyEndian>, 381 ) -> Result<(), ExecError> { 382 let phdr_vaddr = phdr_vaddr.unwrap_or(VirtAddr::new(0)); 383 384 let init_info = param.init_info_mut(); 385 init_info 386 .auxv 387 .insert(AtType::PhEnt as u8, ehdr.e_phentsize as usize); 388 init_info 389 .auxv 390 .insert(AtType::PageSize as u8, MMArch::PAGE_SIZE); 391 init_info.auxv.insert(AtType::Phdr as u8, phdr_vaddr.data()); 392 init_info 393 .auxv 394 .insert(AtType::PhNum as u8, ehdr.e_phnum as usize); 395 init_info 396 .auxv 397 .insert(AtType::Entry as u8, entrypoint_vaddr.data()); 398 399 return Ok(()); 400 } 401 402 /// 解析文件的ehdr parse_ehdr(data: &[u8]) -> Result<FileHeader<AnyEndian>, elf::ParseError>403 fn parse_ehdr(data: &[u8]) -> Result<FileHeader<AnyEndian>, elf::ParseError> { 404 let ident_buf = data.get_bytes(0..elf::abi::EI_NIDENT)?; 405 let ident = elf::file::parse_ident::<AnyEndian>(ident_buf)?; 406 407 let tail_start = elf::abi::EI_NIDENT; 408 let tail_end = match ident.1 { 409 elf::file::Class::ELF32 => tail_start + elf::file::ELF32_EHDR_TAILSIZE, 410 elf::file::Class::ELF64 => tail_start + elf::file::ELF64_EHDR_TAILSIZE, 411 }; 412 let tail_buf = data.get_bytes(tail_start..tail_end)?; 413 414 let ehdr: FileHeader<_> = FileHeader::parse_tail(ident, tail_buf)?; 415 return Ok(ehdr); 416 } 417 418 /// 解析文件的program header table 419 /// 420 /// ## 参数 421 /// 422 /// - `param`：执行参数 423 /// - `ehdr`：文件头 424 /// - `data_buf`：用于缓存SegmentTable的Vec。 425 /// 这是因为SegmentTable的生命周期与data_buf一致。初始化这个Vec的大小为0即可。 426 /// 427 /// ## 说明 428 /// 429 /// 这个函数由elf库的`elf::elf_bytes::find_phdrs`修改而来。 parse_segments<'a>( param: &mut ExecParam, ehdr: &FileHeader<AnyEndian>, data_buf: &'a mut Vec<u8>, ) -> Result<Option<elf::segment::SegmentTable<'a, AnyEndian>>, elf::ParseError>430 fn parse_segments<'a>( 431 param: &mut ExecParam, 432 ehdr: &FileHeader<AnyEndian>, 433 data_buf: &'a mut Vec<u8>, 434 ) -> Result<Option<elf::segment::SegmentTable<'a, AnyEndian>>, elf::ParseError> { 435 // It's Ok to have no program headers 436 if ehdr.e_phoff == 0 { 437 return Ok(None); 438 } 439 let file = param.file_mut(); 440 // If the number of segments is greater than or equal to PN_XNUM (0xffff), 441 // e_phnum is set to PN_XNUM, and the actual number of program header table 442 // entries is contained in the sh_info field of the section header at index 0. 443 let mut phnum = ehdr.e_phnum as usize; 444 if phnum == elf::abi::PN_XNUM as usize { 445 let shoff: usize = ehdr.e_shoff.try_into()?; 446 447 // 从磁盘读取shdr的前2个entry 448 file.lseek(SeekFrom::SeekSet(shoff as i64)) 449 .map_err(|_| elf::ParseError::BadOffset(shoff as u64))?; 450 let shdr_buf_size = ehdr.e_shentsize * 2; 451 let mut shdr_buf = vec![0u8; shdr_buf_size as usize]; 452 file.read(shdr_buf_size as usize, &mut shdr_buf) 453 .map_err(|_| elf::ParseError::BadOffset(shoff as u64))?; 454 455 let mut offset = 0; 456 let shdr0 = <elf::section::SectionHeader as elf::parse::ParseAt>::parse_at( 457 ehdr.endianness, 458 ehdr.class, 459 &mut offset, 460 &shdr_buf, 461 )?; 462 phnum = shdr0.sh_info.try_into()?; 463 } 464 465 // Validate phentsize before trying to read the table so that we can error early for corrupted files 466 let entsize = <ProgramHeader as elf::parse::ParseAt>::validate_entsize( 467 ehdr.class, 468 ehdr.e_phentsize as usize, 469 )?; 470 let phoff: usize = ehdr.e_phoff.try_into()?; 471 let size = entsize 472 .checked_mul(phnum) 473 .ok_or(elf::ParseError::IntegerOverflow)?; 474 phoff 475 .checked_add(size) 476 .ok_or(elf::ParseError::IntegerOverflow)?; 477 478 // 读取program header table 479 480 file.lseek(SeekFrom::SeekSet(phoff as i64)) 481 .map_err(|_| elf::ParseError::BadOffset(phoff as u64))?; 482 data_buf.clear(); 483 data_buf.resize(size, 0); 484 485 file.read(size, data_buf) 486 .expect("read program header table failed"); 487 let buf = data_buf.get_bytes(0..size)?; 488 489 return Ok(Some(elf::segment::SegmentTable::new( 490 ehdr.endianness, 491 ehdr.class, 492 buf, 493 ))); 494 } 495 496 // 解析 PT_GNU_PROPERTY 类型的段 497 // 参照 https://code.dragonos.org.cn/xref/linux-6.1.9/fs/binfmt_elf.c#767 parse_gnu_property() -> Result<(), ExecError>498 fn parse_gnu_property() -> Result<(), ExecError> { 499 return Ok(()); 500 } 501 } 502 503 impl BinaryLoader for ElfLoader { probe(self: &'static Self, param: &ExecParam, buf: &[u8]) -> Result<(), ExecError>504 fn probe(self: &'static Self, param: &ExecParam, buf: &[u8]) -> Result<(), ExecError> { 505 // let elf_bytes = 506 // ElfBytes::<AnyEndian>::minimal_parse(buf).map_err(|_| ExecError::NotExecutable)?; 507 508 let ehdr = Self::parse_ehdr(buf).map_err(|_| ExecError::NotExecutable)?; 509 510 #[cfg(target_arch = "x86_64")] 511 return self.probe_x86_64(param, &ehdr); 512 513 #[cfg(target_arch = "riscv64")] 514 return self.probe_riscv(param, &ehdr); 515 516 #[cfg(not(any(target_arch = "x86_64", target_arch = "riscv64")))] 517 compile_error!("BinaryLoader: Unsupported architecture"); 518 } 519 load( self: &'static Self, param: &mut ExecParam, head_buf: &[u8], ) -> Result<BinaryLoaderResult, ExecError>520 fn load( 521 self: &'static Self, 522 param: &mut ExecParam, 523 head_buf: &[u8], 524 ) -> Result<BinaryLoaderResult, ExecError> { 525 // 解析elf文件头 526 let ehdr = Self::parse_ehdr(head_buf).map_err(|_| ExecError::NotExecutable)?; 527 528 // 参考linux-5.19的load_elf_binary函数 529 // https://code.dragonos.org.cn/xref/linux-5.19.10/fs/binfmt_elf.c?r=&mo=22652&fi=824#1034 530 531 let elf_type = ElfType::from(ehdr.e_type); 532 // kdebug!("ehdr = {:?}", ehdr); 533 534 let binding = param.vm().clone(); 535 let mut user_vm = binding.write(); 536 537 // todo: 增加对user stack上的内存是否具有可执行权限的处理（方法：寻找phdr里面的PT_GNU_STACK段） 538 539 // kdebug!("to parse segments"); 540 // 加载ELF文件并映射到用户空间 541 let mut phdr_buf = Vec::new(); 542 let phdr_table = Self::parse_segments(param, &ehdr, &mut phdr_buf) 543 .map_err(|_| ExecError::ParseError)? 544 .ok_or(ExecError::ParseError)?; 545 let mut _gnu_property_data: Option<ProgramHeader> = None; 546 let interpreter: Option<File> = None; 547 for seg in phdr_table { 548 if seg.p_type == PT_GNU_PROPERTY { 549 _gnu_property_data = Some(seg.clone()); 550 continue; 551 } 552 if seg.p_type != PT_INTERP { 553 continue; 554 } 555 // 接下来处理这个 .interpreter 段以及动态链接器 556 // 参考 https://code.dragonos.org.cn/xref/linux-6.1.9/fs/binfmt_elf.c#881 557 558 if seg.p_filesz > 4096 || seg.p_filesz < 2 { 559 return Err(ExecError::NotExecutable); 560 } 561 562 let interpreter_ptr = unsafe { 563 core::slice::from_raw_parts( 564 seg.p_offset as *const u8, 565 seg.p_filesz.try_into().unwrap(), 566 ) 567 }; 568 let _interpreter_path = core::str::from_utf8(interpreter_ptr).map_err(|e| { 569 ExecError::Other(format!( 570 "Failed to parse the path of dynamic linker with error {}", 571 e 572 )) 573 })?; 574 575 //TODO 加入对动态链接器的加载，参照 https://code.dragonos.org.cn/xref/linux-6.1.9/fs/binfmt_elf.c#890 576 } 577 if interpreter.is_some() { 578 /* Some simple consistency checks for the interpreter */ 579 // 参考 https://code.dragonos.org.cn/xref/linux-6.1.9/fs/binfmt_elf.c#950 580 } 581 Self::parse_gnu_property()?; 582 583 // kdebug!("loadable_sections = {:?}", loadable_sections); 584 585 let mut elf_brk = VirtAddr::new(0); 586 let mut elf_bss = VirtAddr::new(0); 587 let mut start_code: Option<VirtAddr> = None; 588 let mut end_code: Option<VirtAddr> = None; 589 let mut start_data: Option<VirtAddr> = None; 590 let mut end_data: Option<VirtAddr> = None; 591 592 // 加载的时候的偏移量（这个偏移量在加载动态链接段的时候产生） 593 let mut load_bias = 0usize; 594 let mut bss_prot_flags = ProtFlags::empty(); 595 // 是否是第一个加载的段 596 let mut first_pt_load = true; 597 // program header的虚拟地址 598 let mut phdr_vaddr: Option<VirtAddr> = None; 599 let mut _reloc_func_desc = 0usize; 600 // 参考https://code.dragonos.org.cn/xref/linux-6.1.9/fs/binfmt_elf.c#1158，获取要加载的total_size 601 let mut has_load = false; 602 let mut min_address = VirtAddr::new(usize::MAX); 603 let mut max_address = VirtAddr::new(0usize); 604 let loadable_sections = phdr_table 605 .into_iter() 606 .filter(|seg| seg.p_type == elf::abi::PT_LOAD); 607 for seg_to_load in loadable_sections { 608 min_address = min( 609 min_address, 610 self.elf_page_start(VirtAddr::new(seg_to_load.p_vaddr.try_into().unwrap())), 611 ); 612 max_address = max( 613 max_address, 614 VirtAddr::new( 615 (seg_to_load.p_vaddr + seg_to_load.p_memsz) 616 .try_into() 617 .unwrap(), 618 ), 619 ); 620 has_load = true; 621 } 622 let total_size = if has_load { 623 max_address - min_address 624 } else { 625 0 626 }; 627 let loadable_sections = phdr_table 628 .into_iter() 629 .filter(|seg| seg.p_type == elf::abi::PT_LOAD); 630 for seg_to_load in loadable_sections { 631 // kdebug!("seg_to_load = {:?}", seg_to_load); 632 if unlikely(elf_brk > elf_bss) { 633 // kdebug!( 634 // "to set brk, elf_brk = {:?}, elf_bss = {:?}", 635 // elf_brk, 636 // elf_bss 637 // ); 638 self.set_elf_brk( 639 &mut user_vm, 640 elf_bss + load_bias, 641 elf_brk + load_bias, 642 bss_prot_flags, 643 )?; 644 let nbyte = self.elf_page_offset(elf_bss); 645 if nbyte > 0 { 646 let nbyte = min(CurrentElfArch::ELF_PAGE_SIZE - nbyte, elf_brk - elf_bss); 647 unsafe { 648 // This bss-zeroing can fail if the ELF file specifies odd protections. 649 // So we don't check the return value. 650 clear_user(elf_bss + load_bias, nbyte).ok(); 651 } 652 } 653 } 654 655 // 生成ProtFlags. 656 let elf_prot_flags = self.make_prot(seg_to_load.p_flags, interpreter.is_some(), false); 657 658 let mut elf_map_flags = MapFlags::MAP_PRIVATE; 659 660 let vaddr = VirtAddr::new(seg_to_load.p_vaddr.try_into().unwrap()); 661 662 if !first_pt_load { 663 elf_map_flags.insert(MapFlags::MAP_FIXED_NOREPLACE); 664 } else if elf_type == ElfType::Executable { 665 /* 666 * This logic is run once for the first LOAD Program 667 * Header for ET_EXEC binaries. No special handling 668 * is needed. 669 */ 670 elf_map_flags.insert(MapFlags::MAP_FIXED_NOREPLACE); 671 } else if elf_type == ElfType::DSO { 672 // TODO: 支持动态链接 673 if interpreter.is_some() { 674 load_bias = CurrentElfArch::ELF_ET_DYN_BASE; 675 if ProcessManager::current_pcb() 676 .flags() 677 .contains(ProcessFlags::RANDOMIZE) 678 { 679 //这里x86下需要一个随机加载的方法，但是很多架构，比如Risc-V都是0，就暂时不写了 680 } else { 681 load_bias = 0; 682 } 683 } 684 load_bias = self 685 .elf_page_start(VirtAddr::new( 686 load_bias - TryInto::<usize>::try_into(seg_to_load.p_vaddr).unwrap(), 687 )) 688 .data(); 689 if total_size == 0 { 690 return Err(ExecError::InvalidParemeter); 691 } 692 } 693 694 // 加载这个段到用户空间 695 696 let e = self 697 .load_elf_segment( 698 &mut user_vm, 699 param, 700 &seg_to_load, 701 vaddr + load_bias, 702 &elf_prot_flags, 703 &elf_map_flags, 704 total_size, 705 ) 706 .map_err(|e| match e { 707 SystemError::EFAULT => ExecError::BadAddress(None), 708 SystemError::ENOMEM => ExecError::OutOfMemory, 709 _ => ExecError::Other(format!("load_elf_segment failed: {:?}", e)), 710 })?; 711 712 // 如果地址不对，那么就报错 713 if !e.1 { 714 return Err(ExecError::BadAddress(Some(e.0))); 715 } 716 717 if first_pt_load { 718 first_pt_load = false; 719 if elf_type == ElfType::DSO { 720 // todo: 在这里增加对load_bias和reloc_func_desc的更新代码 721 load_bias += e.0.data() 722 - self 723 .elf_page_start(VirtAddr::new( 724 load_bias 725 + TryInto::<usize>::try_into(seg_to_load.p_vaddr).unwrap(), 726 )) 727 .data(); 728 _reloc_func_desc = load_bias; 729 } 730 } 731 732 // kdebug!("seg_to_load.p_offset={}", seg_to_load.p_offset); 733 // kdebug!("e_phoff={}", ehdr.e_phoff); 734 // kdebug!("seg_to_load.p_filesz={}", seg_to_load.p_filesz); 735 // Figure out which segment in the file contains the Program Header Table, 736 // and map to the associated virtual address. 737 if (seg_to_load.p_offset <= ehdr.e_phoff) 738 && (ehdr.e_phoff < (seg_to_load.p_offset + seg_to_load.p_filesz)) 739 { 740 phdr_vaddr = Some(VirtAddr::new( 741 (ehdr.e_phoff - seg_to_load.p_offset + seg_to_load.p_vaddr) as usize, 742 )); 743 } 744 745 let p_vaddr = VirtAddr::new(seg_to_load.p_vaddr as usize); 746 if (seg_to_load.p_flags & elf::abi::PF_X) != 0 { 747 if start_code.is_none() || start_code.as_ref().unwrap() > &p_vaddr { 748 start_code = Some(p_vaddr); 749 } 750 } 751 752 if start_data.is_none() 753 || (start_data.is_some() && start_data.as_ref().unwrap() > &p_vaddr) 754 { 755 start_data = Some(p_vaddr); 756 } 757 758 // 如果程序段要加载的目标地址不在用户空间内，或者是其他不合法的情况，那么就报错 759 if !p_vaddr.check_user() 760 || seg_to_load.p_filesz > seg_to_load.p_memsz 761 || self.elf_page_align_up(p_vaddr + seg_to_load.p_memsz as usize) 762 >= MMArch::USER_END_VADDR 763 { 764 // kdebug!("ERR: p_vaddr={p_vaddr:?}"); 765 return Err(ExecError::InvalidParemeter); 766 } 767 768 // end vaddr of this segment(code+data+bss) 769 let seg_end_vaddr_f = self.elf_page_align_up(VirtAddr::new( 770 (seg_to_load.p_vaddr + seg_to_load.p_filesz) as usize, 771 )); 772 773 if seg_end_vaddr_f > elf_bss { 774 elf_bss = seg_end_vaddr_f; 775 } 776 777 if ((seg_to_load.p_flags & elf::abi::PF_X) != 0) 778 && (end_code.is_none() 779 || (end_code.is_some() && end_code.as_ref().unwrap() < &seg_end_vaddr_f)) 780 { 781 end_code = Some(seg_end_vaddr_f); 782 } 783 784 if end_data.is_none() 785 || (end_data.is_some() && end_data.as_ref().unwrap() < &seg_end_vaddr_f) 786 { 787 end_data = Some(seg_end_vaddr_f); 788 } 789 790 let seg_end_vaddr = VirtAddr::new((seg_to_load.p_vaddr + seg_to_load.p_memsz) as usize); 791 792 if seg_end_vaddr > elf_brk { 793 bss_prot_flags = elf_prot_flags; 794 elf_brk = seg_end_vaddr; 795 } 796 } 797 // kdebug!("elf load: phdr_vaddr={phdr_vaddr:?}"); 798 let program_entrypoint = VirtAddr::new(ehdr.e_entry as usize + load_bias); 799 let phdr_vaddr = if phdr_vaddr.is_some() { 800 Some(phdr_vaddr.unwrap() + load_bias) 801 } else { 802 None 803 }; 804 805 elf_bss += load_bias; 806 elf_brk += load_bias; 807 start_code = start_code.map(|v| v + load_bias); 808 end_code = end_code.map(|v| v + load_bias); 809 start_data = start_data.map(|v| v + load_bias); 810 end_data = end_data.map(|v| v + load_bias); 811 812 // kdebug!( 813 // "to set brk: elf_bss: {:?}, elf_brk: {:?}, bss_prot_flags: {:?}", 814 // elf_bss, 815 // elf_brk, 816 // bss_prot_flags 817 // ); 818 self.set_elf_brk(&mut user_vm, elf_bss, elf_brk, bss_prot_flags)?; 819 820 if likely(elf_bss != elf_brk) && unlikely(self.pad_zero(elf_bss).is_err()) { 821 // kdebug!("elf_bss = {elf_bss:?}, elf_brk = {elf_brk:?}"); 822 return Err(ExecError::BadAddress(Some(elf_bss))); 823 } 824 if interpreter.is_some() { 825 // TODO 添加对动态加载器的处理 826 // 参考 https://code.dragonos.org.cn/xref/linux-6.1.9/fs/binfmt_elf.c#1249 827 } 828 // kdebug!("to create auxv"); 829 830 self.create_auxv(param, program_entrypoint, phdr_vaddr, &ehdr)?; 831 832 // kdebug!("auxv create ok"); 833 user_vm.start_code = start_code.unwrap_or(VirtAddr::new(0)); 834 user_vm.end_code = end_code.unwrap_or(VirtAddr::new(0)); 835 user_vm.start_data = start_data.unwrap_or(VirtAddr::new(0)); 836 user_vm.end_data = end_data.unwrap_or(VirtAddr::new(0)); 837 838 let result = BinaryLoaderResult::new(program_entrypoint); 839 // kdebug!("elf load OK!!!"); 840 return Ok(result); 841 } 842 } 843 844 /// Elf机器架构，对应于e_machine字段。在ABI中，以EM_开头的常量是e_machine字段的值。 845 #[derive(Debug, Eq, PartialEq)] 846 pub enum ElfMachine { 847 I386, 848 AArch32, 849 AArch64, 850 X86_64, 851 RiscV, 852 /// 龙芯架构 853 LoongArch, 854 /// 未知架构 855 Unknown, 856 } 857 858 impl From<u16> for ElfMachine { from(machine: u16) -> Self859 fn from(machine: u16) -> Self { 860 match machine { 861 0x03 => Self::I386, 862 0x28 => Self::AArch32, 863 0xb7 => Self::AArch64, 864 0x3e => Self::X86_64, 865 0xf3 => Self::RiscV, 866 0x102 => Self::LoongArch, 867 // 未知架构 868 _ => Self::Unknown, 869 } 870 } 871 } 872 873 /// Elf文件类型，对应于e_type字段。在ABI中，以ET_开头的常量是e_type字段的值。 874 #[derive(Debug, Eq, PartialEq)] 875 pub enum ElfType { 876 /// 可重定位文件 877 Relocatable, 878 /// 可执行文件 879 Executable, 880 /// 动态链接库 881 DSO, 882 /// 核心转储文件 883 Core, 884 /// 未知类型 885 Unknown, 886 } 887 888 impl From<u16> for ElfType { from(elf_type: u16) -> Self889 fn from(elf_type: u16) -> Self { 890 match elf_type { 891 0x01 => Self::Relocatable, 892 0x02 => Self::Executable, 893 0x03 => Self::DSO, 894 0x04 => Self::Core, 895 _ => Self::Unknown, 896 } 897 } 898 } 899 900 // Simple convenience extension trait to wrap get() with .ok_or(SliceReadError) 901 trait ReadBytesExt<'data> { get_bytes(self, range: Range<usize>) -> Result<&'data [u8], elf::ParseError>902 fn get_bytes(self, range: Range<usize>) -> Result<&'data [u8], elf::ParseError>; 903 } 904 impl<'data> ReadBytesExt<'data> for &'data [u8] { get_bytes(self, range: Range<usize>) -> Result<&'data [u8], elf::ParseError>905 fn get_bytes(self, range: Range<usize>) -> Result<&'data [u8], elf::ParseError> { 906 let start = range.start; 907 let end = range.end; 908 self.get(range) 909 .ok_or(elf::ParseError::SliceReadError((start, end))) 910 } 911 } 912