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 54 pub const fn new() -> Self { 55 Self 56 } 57 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")] 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")] 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 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 146 fn elf_page_offset(&self, addr: VirtAddr) -> usize { 147 addr.data() & (CurrentElfArch::ELF_PAGE_SIZE - 1) 148 } 149 150 fn elf_page_start(&self, addr: VirtAddr) -> VirtAddr { 151 VirtAddr::new(addr.data() & (!(CurrentElfArch::ELF_PAGE_SIZE - 1))) 152 } 153 154 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 162 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 197 #[allow(clippy::too_many_arguments)] 198 fn load_elf_segment( 199 &self, 200 user_vm_guard: &mut RwLockWriteGuard<'_, InnerAddressSpace>, 201 param: &mut ExecParam, 202 phent: &ProgramHeader, 203 mut addr_to_map: VirtAddr, 204 prot: &ProtFlags, 205 map_flags: &MapFlags, 206 total_size: usize, 207 ) -> Result<(VirtAddr, bool), SystemError> { 208 // kdebug!("load_elf_segment: addr_to_map={:?}", addr_to_map); 209 210 // 映射位置的偏移量（页内偏移） 211 let beginning_page_offset = self.elf_page_offset(addr_to_map); 212 addr_to_map = self.elf_page_start(addr_to_map); 213 // 计算要映射的内存的大小 214 let map_size = phent.p_filesz as usize + beginning_page_offset; 215 let map_size = self.elf_page_align_up(VirtAddr::new(map_size)).data(); 216 // 当前段在文件中的大小 217 let seg_in_file_size = phent.p_filesz as usize; 218 // 当前段在文件中的偏移量 219 let file_offset = phent.p_offset as usize; 220 221 // 如果当前段的大小为0，则直接返回. 222 // 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0 223 if map_size == 0 { 224 return Ok((addr_to_map, true)); 225 } 226 227 let map_err_handler = |err: SystemError| { 228 if err == SystemError::EEXIST { 229 kerror!( 230 "Pid: {:?}, elf segment at {:p} overlaps with existing mapping", 231 ProcessManager::current_pcb().pid(), 232 addr_to_map.as_ptr::<u8>() 233 ); 234 } 235 err 236 }; 237 // 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 238 let tmp_prot = if !prot.contains(ProtFlags::PROT_WRITE) { 239 *prot | ProtFlags::PROT_WRITE 240 } else { 241 *prot 242 }; 243 244 // 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 245 let map_addr: VirtAddr; 246 247 // total_size is the size of the ELF (interpreter) image. 248 // The _first_ mmap needs to know the full size, otherwise 249 // randomization might put this image into an overlapping 250 // position with the ELF binary image. (since size < total_size) 251 // So we first map the 'big' image - and unmap the remainder at 252 // the end. (which unmap is needed for ELF images with holes.) 253 if total_size != 0 { 254 let total_size = self.elf_page_align_up(VirtAddr::new(total_size)).data(); 255 256 // kdebug!("total_size={}", total_size); 257 258 map_addr = user_vm_guard 259 .map_anonymous(addr_to_map, total_size, tmp_prot, *map_flags, false) 260 .map_err(map_err_handler)? 261 .virt_address(); 262 // kdebug!("map ok: addr_to_map={:?}", addr_to_map); 263 264 let to_unmap = map_addr + map_size; 265 let to_unmap_size = total_size - map_size; 266 267 // kdebug!("to_unmap={:?}, to_unmap_size={}", to_unmap, to_unmap_size); 268 user_vm_guard.munmap( 269 VirtPageFrame::new(to_unmap), 270 PageFrameCount::from_bytes(to_unmap_size).unwrap(), 271 )?; 272 273 // 加载文件到内存 274 self.do_load_file( 275 map_addr + beginning_page_offset, 276 seg_in_file_size, 277 file_offset, 278 param, 279 )?; 280 if tmp_prot != *prot { 281 user_vm_guard.mprotect( 282 VirtPageFrame::new(map_addr), 283 PageFrameCount::from_bytes(page_align_up(map_size)).unwrap(), 284 *prot, 285 )?; 286 } 287 } else { 288 // kdebug!("total size = 0"); 289 290 map_addr = user_vm_guard 291 .map_anonymous(addr_to_map, map_size, tmp_prot, *map_flags, false)? 292 .virt_address(); 293 // kdebug!( 294 // "map ok: addr_to_map={:?}, map_addr={map_addr:?},beginning_page_offset={beginning_page_offset:?}", 295 // addr_to_map 296 // ); 297 298 // 加载文件到内存 299 self.do_load_file( 300 map_addr + beginning_page_offset, 301 seg_in_file_size, 302 file_offset, 303 param, 304 )?; 305 306 if tmp_prot != *prot { 307 user_vm_guard.mprotect( 308 VirtPageFrame::new(map_addr), 309 PageFrameCount::from_bytes(page_align_up(map_size)).unwrap(), 310 *prot, 311 )?; 312 } 313 } 314 // kdebug!("load_elf_segment OK: map_addr={:?}", map_addr); 315 return Ok((map_addr, true)); 316 } 317 318 /// 加载ELF文件到用户空间 319 /// 320 /// ## 参数 321 /// 322 /// - `vaddr`：要加载到的虚拟地址 323 /// - `size`：要加载的大小 324 /// - `offset_in_file`：在文件内的偏移量 325 /// - `param`：执行参数 326 fn do_load_file( 327 &self, 328 mut vaddr: VirtAddr, 329 size: usize, 330 offset_in_file: usize, 331 param: &mut ExecParam, 332 ) -> Result<(), SystemError> { 333 let file = param.file_mut(); 334 if (file.metadata()?.size as usize) < offset_in_file + size { 335 return Err(SystemError::ENOEXEC); 336 } 337 let buf_size = min(size, Self::FILE_READ_BUF_SIZE); 338 let mut buf = vec![0u8; buf_size]; 339 340 let mut remain = size; 341 342 file.lseek(SeekFrom::SeekSet(offset_in_file as i64))?; 343 344 while remain > 0 { 345 let read_size = min(remain, buf_size); 346 file.read(read_size, &mut buf[..read_size])?; 347 // kdebug!("copy_to_user: vaddr={:?}, read_size = {read_size}", vaddr); 348 unsafe { 349 copy_to_user(vaddr, &buf[..read_size]).map_err(|_| SystemError::EFAULT)?; 350 } 351 352 vaddr += read_size; 353 remain -= read_size; 354 } 355 return Ok(()); 356 } 357 358 /// 我们需要显式的把数据段之后剩余的内存页都清零。 359 fn pad_zero(&self, elf_bss: VirtAddr) -> Result<(), SystemError> { 360 let nbyte = self.elf_page_offset(elf_bss); 361 if nbyte > 0 { 362 let nbyte = CurrentElfArch::ELF_PAGE_SIZE - nbyte; 363 unsafe { clear_user(elf_bss, nbyte).map_err(|_| SystemError::EFAULT) }?; 364 } 365 return Ok(()); 366 } 367 368 /// 创建auxv 369 /// 370 /// ## 参数 371 /// 372 /// - `param`：执行参数 373 /// - `entrypoint_vaddr`：程序入口地址 374 /// - `phdr_vaddr`：程序头表地址 375 /// - `elf_header`：ELF文件头 376 fn create_auxv( 377 &self, 378 param: &mut ExecParam, 379 entrypoint_vaddr: VirtAddr, 380 phdr_vaddr: Option<VirtAddr>, 381 ehdr: &elf::file::FileHeader<AnyEndian>, 382 ) -> Result<(), ExecError> { 383 let phdr_vaddr = phdr_vaddr.unwrap_or(VirtAddr::new(0)); 384 385 let init_info = param.init_info_mut(); 386 init_info 387 .auxv 388 .insert(AtType::PhEnt as u8, ehdr.e_phentsize as usize); 389 init_info 390 .auxv 391 .insert(AtType::PageSize as u8, MMArch::PAGE_SIZE); 392 init_info.auxv.insert(AtType::Phdr as u8, phdr_vaddr.data()); 393 init_info 394 .auxv 395 .insert(AtType::PhNum as u8, ehdr.e_phnum as usize); 396 init_info 397 .auxv 398 .insert(AtType::Entry as u8, entrypoint_vaddr.data()); 399 400 return Ok(()); 401 } 402 403 /// 解析文件的ehdr 404 fn parse_ehdr(data: &[u8]) -> Result<FileHeader<AnyEndian>, elf::ParseError> { 405 let ident_buf = data.get_bytes(0..elf::abi::EI_NIDENT)?; 406 let ident = elf::file::parse_ident::<AnyEndian>(ident_buf)?; 407 408 let tail_start = elf::abi::EI_NIDENT; 409 let tail_end = match ident.1 { 410 elf::file::Class::ELF32 => tail_start + elf::file::ELF32_EHDR_TAILSIZE, 411 elf::file::Class::ELF64 => tail_start + elf::file::ELF64_EHDR_TAILSIZE, 412 }; 413 let tail_buf = data.get_bytes(tail_start..tail_end)?; 414 415 let ehdr: FileHeader<_> = FileHeader::parse_tail(ident, tail_buf)?; 416 return Ok(ehdr); 417 } 418 419 /// 解析文件的program header table 420 /// 421 /// ## 参数 422 /// 423 /// - `param`：执行参数 424 /// - `ehdr`：文件头 425 /// - `data_buf`：用于缓存SegmentTable的Vec。 426 /// 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。 427 /// 428 /// ## 说明 429 /// 430 /// 这个函数由elf库的`elf::elf_bytes::find_phdrs`修改而来。 431 fn parse_segments<'a>( 432 param: &mut ExecParam, 433 ehdr: &FileHeader<AnyEndian>, 434 data_buf: &'a mut Vec<u8>, 435 ) -> Result<Option<elf::segment::SegmentTable<'a, AnyEndian>>, elf::ParseError> { 436 // It's Ok to have no program headers 437 if ehdr.e_phoff == 0 { 438 return Ok(None); 439 } 440 let file = param.file_mut(); 441 // If the number of segments is greater than or equal to PN_XNUM (0xffff), 442 // e_phnum is set to PN_XNUM, and the actual number of program header table 443 // entries is contained in the sh_info field of the section header at index 0. 444 let mut phnum = ehdr.e_phnum as usize; 445 if phnum == elf::abi::PN_XNUM as usize { 446 let shoff: usize = ehdr.e_shoff.try_into()?; 447 448 // 从磁盘读取shdr的前2个entry 449 file.lseek(SeekFrom::SeekSet(shoff as i64)) 450 .map_err(|_| elf::ParseError::BadOffset(shoff as u64))?; 451 let shdr_buf_size = ehdr.e_shentsize * 2; 452 let mut shdr_buf = vec![0u8; shdr_buf_size as usize]; 453 file.read(shdr_buf_size as usize, &mut shdr_buf) 454 .map_err(|_| elf::ParseError::BadOffset(shoff as u64))?; 455 456 let mut offset = 0; 457 let shdr0 = <elf::section::SectionHeader as elf::parse::ParseAt>::parse_at( 458 ehdr.endianness, 459 ehdr.class, 460 &mut offset, 461 &shdr_buf, 462 )?; 463 phnum = shdr0.sh_info.try_into()?; 464 } 465 466 // Validate phentsize before trying to read the table so that we can error early for corrupted files 467 let entsize = <ProgramHeader as elf::parse::ParseAt>::validate_entsize( 468 ehdr.class, 469 ehdr.e_phentsize as usize, 470 )?; 471 let phoff: usize = ehdr.e_phoff.try_into()?; 472 let size = entsize 473 .checked_mul(phnum) 474 .ok_or(elf::ParseError::IntegerOverflow)?; 475 phoff 476 .checked_add(size) 477 .ok_or(elf::ParseError::IntegerOverflow)?; 478 479 // 读取program header table 480 481 file.lseek(SeekFrom::SeekSet(phoff as i64)) 482 .map_err(|_| elf::ParseError::BadOffset(phoff as u64))?; 483 data_buf.clear(); 484 data_buf.resize(size, 0); 485 486 file.read(size, data_buf) 487 .expect("read program header table failed"); 488 let buf = data_buf.get_bytes(0..size)?; 489 490 return Ok(Some(elf::segment::SegmentTable::new( 491 ehdr.endianness, 492 ehdr.class, 493 buf, 494 ))); 495 } 496 497 // 解析 PT_GNU_PROPERTY 类型的段 498 // 参照 https://code.dragonos.org.cn/xref/linux-6.1.9/fs/binfmt_elf.c#767 499 fn parse_gnu_property() -> Result<(), ExecError> { 500 return Ok(()); 501 } 502 } 503 504 impl BinaryLoader for ElfLoader { 505 fn probe(&'static self, param: &ExecParam, buf: &[u8]) -> Result<(), ExecError> { 506 // let elf_bytes = 507 // ElfBytes::<AnyEndian>::minimal_parse(buf).map_err(|_| ExecError::NotExecutable)?; 508 509 let ehdr = Self::parse_ehdr(buf).map_err(|_| ExecError::NotExecutable)?; 510 511 #[cfg(target_arch = "x86_64")] 512 return self.probe_x86_64(param, &ehdr); 513 514 #[cfg(target_arch = "riscv64")] 515 return self.probe_riscv(param, &ehdr); 516 517 #[cfg(not(any(target_arch = "x86_64", target_arch = "riscv64")))] 518 compile_error!("BinaryLoader: Unsupported architecture"); 519 } 520 521 fn load( 522 &'static self, 523 param: &mut ExecParam, 524 head_buf: &[u8], 525 ) -> Result<BinaryLoaderResult, ExecError> { 526 // 解析elf文件头 527 let ehdr = Self::parse_ehdr(head_buf).map_err(|_| ExecError::NotExecutable)?; 528 529 // 参考linux-5.19的load_elf_binary函数 530 // https://code.dragonos.org.cn/xref/linux-5.19.10/fs/binfmt_elf.c?r=&mo=22652&fi=824#1034 531 532 let elf_type = ElfType::from(ehdr.e_type); 533 // kdebug!("ehdr = {:?}", ehdr); 534 535 let binding = param.vm().clone(); 536 let mut user_vm = binding.write(); 537 538 // 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） 539 540 // kdebug!("to parse segments"); 541 // 加载ELF文件并映射到用户空间 542 let mut phdr_buf = Vec::new(); 543 let phdr_table = Self::parse_segments(param, &ehdr, &mut phdr_buf) 544 .map_err(|_| ExecError::ParseError)? 545 .ok_or(ExecError::ParseError)?; 546 let mut _gnu_property_data: Option<ProgramHeader> = None; 547 let interpreter: Option<File> = None; 548 for seg in phdr_table { 549 if seg.p_type == PT_GNU_PROPERTY { 550 _gnu_property_data = Some(seg); 551 continue; 552 } 553 if seg.p_type != PT_INTERP { 554 continue; 555 } 556 // 接下来处理这个 .interpreter 段以及动态链接器 557 // 参考 https://code.dragonos.org.cn/xref/linux-6.1.9/fs/binfmt_elf.c#881 558 559 if seg.p_filesz > 4096 || seg.p_filesz < 2 { 560 return Err(ExecError::NotExecutable); 561 } 562 563 let interpreter_ptr = unsafe { 564 core::slice::from_raw_parts( 565 seg.p_offset as *const u8, 566 seg.p_filesz.try_into().unwrap(), 567 ) 568 }; 569 let _interpreter_path = core::str::from_utf8(interpreter_ptr).map_err(|e| { 570 ExecError::Other(format!( 571 "Failed to parse the path of dynamic linker with error {}", 572 e 573 )) 574 })?; 575 576 //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#890 577 } 578 if interpreter.is_some() { 579 /* Some simple consistency checks for the interpreter */ 580 // 参考 https://code.dragonos.org.cn/xref/linux-6.1.9/fs/binfmt_elf.c#950 581 } 582 Self::parse_gnu_property()?; 583 584 // kdebug!("loadable_sections = {:?}", loadable_sections); 585 586 let mut elf_brk = VirtAddr::new(0); 587 let mut elf_bss = VirtAddr::new(0); 588 let mut start_code: Option<VirtAddr> = None; 589 let mut end_code: Option<VirtAddr> = None; 590 let mut start_data: Option<VirtAddr> = None; 591 let mut end_data: Option<VirtAddr> = None; 592 593 // 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） 594 let mut load_bias = 0usize; 595 let mut bss_prot_flags = ProtFlags::empty(); 596 // 是否是第一个加载的段 597 let mut first_pt_load = true; 598 // program header的虚拟地址 599 let mut phdr_vaddr: Option<VirtAddr> = None; 600 let mut _reloc_func_desc = 0usize; 601 // 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 602 let mut has_load = false; 603 let mut min_address = VirtAddr::new(usize::MAX); 604 let mut max_address = VirtAddr::new(0usize); 605 let loadable_sections = phdr_table 606 .into_iter() 607 .filter(|seg| seg.p_type == elf::abi::PT_LOAD); 608 for seg_to_load in loadable_sections { 609 min_address = min( 610 min_address, 611 self.elf_page_start(VirtAddr::new(seg_to_load.p_vaddr.try_into().unwrap())), 612 ); 613 max_address = max( 614 max_address, 615 VirtAddr::new( 616 (seg_to_load.p_vaddr + seg_to_load.p_memsz) 617 .try_into() 618 .unwrap(), 619 ), 620 ); 621 has_load = true; 622 } 623 let total_size = if has_load { 624 max_address - min_address 625 } else { 626 0 627 }; 628 let loadable_sections = phdr_table 629 .into_iter() 630 .filter(|seg| seg.p_type == elf::abi::PT_LOAD); 631 for seg_to_load in loadable_sections { 632 // kdebug!("seg_to_load = {:?}", seg_to_load); 633 if unlikely(elf_brk > elf_bss) { 634 // kdebug!( 635 // "to set brk, elf_brk = {:?}, elf_bss = {:?}", 636 // elf_brk, 637 // elf_bss 638 // ); 639 self.set_elf_brk( 640 &mut user_vm, 641 elf_bss + load_bias, 642 elf_brk + load_bias, 643 bss_prot_flags, 644 )?; 645 let nbyte = self.elf_page_offset(elf_bss); 646 if nbyte > 0 { 647 let nbyte = min(CurrentElfArch::ELF_PAGE_SIZE - nbyte, elf_brk - elf_bss); 648 unsafe { 649 // This bss-zeroing can fail if the ELF file specifies odd protections. 650 // So we don't check the return value. 651 clear_user(elf_bss + load_bias, nbyte).ok(); 652 } 653 } 654 } 655 656 // 生成ProtFlags. 657 let elf_prot_flags = self.make_prot(seg_to_load.p_flags, interpreter.is_some(), false); 658 659 let mut elf_map_flags = MapFlags::MAP_PRIVATE; 660 661 let vaddr = VirtAddr::new(seg_to_load.p_vaddr.try_into().unwrap()); 662 663 #[allow(clippy::if_same_then_else)] 664 if !first_pt_load { 665 elf_map_flags.insert(MapFlags::MAP_FIXED_NOREPLACE); 666 } else if elf_type == ElfType::Executable { 667 /* 668 * This logic is run once for the first LOAD Program 669 * Header for ET_EXEC binaries. No special handling 670 * is needed. 671 */ 672 elf_map_flags.insert(MapFlags::MAP_FIXED_NOREPLACE); 673 } else if elf_type == ElfType::DSO { 674 // TODO: 支持动态链接 675 if interpreter.is_some() { 676 load_bias = CurrentElfArch::ELF_ET_DYN_BASE; 677 if ProcessManager::current_pcb() 678 .flags() 679 .contains(ProcessFlags::RANDOMIZE) 680 { 681 //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 682 } else { 683 load_bias = 0; 684 } 685 } 686 load_bias = self 687 .elf_page_start(VirtAddr::new( 688 load_bias - TryInto::<usize>::try_into(seg_to_load.p_vaddr).unwrap(), 689 )) 690 .data(); 691 if total_size == 0 { 692 return Err(ExecError::InvalidParemeter); 693 } 694 } 695 696 // 加载这个段到用户空间 697 698 let e = self 699 .load_elf_segment( 700 &mut user_vm, 701 param, 702 &seg_to_load, 703 vaddr + load_bias, 704 &elf_prot_flags, 705 &elf_map_flags, 706 total_size, 707 ) 708 .map_err(|e| match e { 709 SystemError::EFAULT => ExecError::BadAddress(None), 710 SystemError::ENOMEM => ExecError::OutOfMemory, 711 _ => ExecError::Other(format!("load_elf_segment failed: {:?}", e)), 712 })?; 713 714 // 如果地址不对，那么就报错 715 if !e.1 { 716 return Err(ExecError::BadAddress(Some(e.0))); 717 } 718 719 if first_pt_load { 720 first_pt_load = false; 721 if elf_type == ElfType::DSO { 722 // todo: 在这里增加对load_bias和reloc_func_desc的更新代码 723 load_bias += e.0.data() 724 - self 725 .elf_page_start(VirtAddr::new( 726 load_bias 727 + TryInto::<usize>::try_into(seg_to_load.p_vaddr).unwrap(), 728 )) 729 .data(); 730 _reloc_func_desc = load_bias; 731 } 732 } 733 734 // kdebug!("seg_to_load.p_offset={}", seg_to_load.p_offset); 735 // kdebug!("e_phoff={}", ehdr.e_phoff); 736 // kdebug!("seg_to_load.p_filesz={}", seg_to_load.p_filesz); 737 // Figure out which segment in the file contains the Program Header Table, 738 // and map to the associated virtual address. 739 if (seg_to_load.p_offset <= ehdr.e_phoff) 740 && (ehdr.e_phoff < (seg_to_load.p_offset + seg_to_load.p_filesz)) 741 { 742 phdr_vaddr = Some(VirtAddr::new( 743 (ehdr.e_phoff - seg_to_load.p_offset + seg_to_load.p_vaddr) as usize, 744 )); 745 } 746 747 let p_vaddr = VirtAddr::new(seg_to_load.p_vaddr as usize); 748 if (seg_to_load.p_flags & elf::abi::PF_X) != 0 749 && (start_code.is_none() || start_code.as_ref().unwrap() > &p_vaddr) 750 { 751 start_code = Some(p_vaddr); 752 } 753 754 if start_data.is_none() 755 || (start_data.is_some() && start_data.as_ref().unwrap() > &p_vaddr) 756 { 757 start_data = Some(p_vaddr); 758 } 759 760 // 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 761 if !p_vaddr.check_user() 762 || seg_to_load.p_filesz > seg_to_load.p_memsz 763 || self.elf_page_align_up(p_vaddr + seg_to_load.p_memsz as usize) 764 >= MMArch::USER_END_VADDR 765 { 766 // kdebug!("ERR: p_vaddr={p_vaddr:?}"); 767 return Err(ExecError::InvalidParemeter); 768 } 769 770 // end vaddr of this segment(code+data+bss) 771 let seg_end_vaddr_f = self.elf_page_align_up(VirtAddr::new( 772 (seg_to_load.p_vaddr + seg_to_load.p_filesz) as usize, 773 )); 774 775 if seg_end_vaddr_f > elf_bss { 776 elf_bss = seg_end_vaddr_f; 777 } 778 779 if ((seg_to_load.p_flags & elf::abi::PF_X) != 0) 780 && (end_code.is_none() 781 || (end_code.is_some() && end_code.as_ref().unwrap() < &seg_end_vaddr_f)) 782 { 783 end_code = Some(seg_end_vaddr_f); 784 } 785 786 if end_data.is_none() 787 || (end_data.is_some() && end_data.as_ref().unwrap() < &seg_end_vaddr_f) 788 { 789 end_data = Some(seg_end_vaddr_f); 790 } 791 792 let seg_end_vaddr = VirtAddr::new((seg_to_load.p_vaddr + seg_to_load.p_memsz) as usize); 793 794 if seg_end_vaddr > elf_brk { 795 bss_prot_flags = elf_prot_flags; 796 elf_brk = seg_end_vaddr; 797 } 798 } 799 // kdebug!("elf load: phdr_vaddr={phdr_vaddr:?}"); 800 let program_entrypoint = VirtAddr::new(ehdr.e_entry as usize + load_bias); 801 let phdr_vaddr = phdr_vaddr.map(|phdr_vaddr| phdr_vaddr + load_bias); 802 803 elf_bss += load_bias; 804 elf_brk += load_bias; 805 start_code = start_code.map(|v| v + load_bias); 806 end_code = end_code.map(|v| v + load_bias); 807 start_data = start_data.map(|v| v + load_bias); 808 end_data = end_data.map(|v| v + load_bias); 809 810 // kdebug!( 811 // "to set brk: elf_bss: {:?}, elf_brk: {:?}, bss_prot_flags: {:?}", 812 // elf_bss, 813 // elf_brk, 814 // bss_prot_flags 815 // ); 816 self.set_elf_brk(&mut user_vm, elf_bss, elf_brk, bss_prot_flags)?; 817 818 if likely(elf_bss != elf_brk) && unlikely(self.pad_zero(elf_bss).is_err()) { 819 // kdebug!("elf_bss = {elf_bss:?}, elf_brk = {elf_brk:?}"); 820 return Err(ExecError::BadAddress(Some(elf_bss))); 821 } 822 if interpreter.is_some() { 823 // TODO 添加对动态加载器的处理 824 // 参考 https://code.dragonos.org.cn/xref/linux-6.1.9/fs/binfmt_elf.c#1249 825 } 826 // kdebug!("to create auxv"); 827 828 self.create_auxv(param, program_entrypoint, phdr_vaddr, &ehdr)?; 829 830 // kdebug!("auxv create ok"); 831 user_vm.start_code = start_code.unwrap_or(VirtAddr::new(0)); 832 user_vm.end_code = end_code.unwrap_or(VirtAddr::new(0)); 833 user_vm.start_data = start_data.unwrap_or(VirtAddr::new(0)); 834 user_vm.end_data = end_data.unwrap_or(VirtAddr::new(0)); 835 836 let result = BinaryLoaderResult::new(program_entrypoint); 837 // kdebug!("elf load OK!!!"); 838 return Ok(result); 839 } 840 } 841 842 /// 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。 843 #[derive(Debug, Eq, PartialEq)] 844 pub enum ElfMachine { 845 I386, 846 AArch32, 847 AArch64, 848 X86_64, 849 RiscV, 850 /// 龙芯架构 851 LoongArch, 852 /// 未知架构 853 Unknown, 854 } 855 856 impl From<u16> for ElfMachine { 857 fn from(machine: u16) -> Self { 858 match machine { 859 0x03 => Self::I386, 860 0x28 => Self::AArch32, 861 0xb7 => Self::AArch64, 862 0x3e => Self::X86_64, 863 0xf3 => Self::RiscV, 864 0x102 => Self::LoongArch, 865 // 未知架构 866 _ => Self::Unknown, 867 } 868 } 869 } 870 871 /// 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。 872 #[derive(Debug, Eq, PartialEq)] 873 pub enum ElfType { 874 /// 可重定位文件 875 Relocatable, 876 /// 可执行文件 877 Executable, 878 /// 动态链接库 879 DSO, 880 /// 核心转储文件 881 Core, 882 /// 未知类型 883 Unknown, 884 } 885 886 impl From<u16> for ElfType { 887 fn from(elf_type: u16) -> Self { 888 match elf_type { 889 0x01 => Self::Relocatable, 890 0x02 => Self::Executable, 891 0x03 => Self::DSO, 892 0x04 => Self::Core, 893 _ => Self::Unknown, 894 } 895 } 896 } 897 898 // Simple convenience extension trait to wrap get() with .ok_or(SliceReadError) 899 trait ReadBytesExt<'data> { 900 fn get_bytes(self, range: Range<usize>) -> Result<&'data [u8], elf::ParseError>; 901 } 902 impl<'data> ReadBytesExt<'data> for &'data [u8] { 903 fn get_bytes(self, range: Range<usize>) -> Result<&'data [u8], elf::ParseError> { 904 let start = range.start; 905 let end = range.end; 906 self.get(range) 907 .ok_or(elf::ParseError::SliceReadError((start, end))) 908 } 909 } 910