1 use core::{ffi::c_void, intrinsics::unlikely, mem::size_of}; 2 3 use log::error; 4 use system_error::SystemError; 5 6 use crate::{ 7 arch::{ 8 fpu::FpState, 9 interrupt::TrapFrame, 10 process::table::{USER_CS, USER_DS}, 11 CurrentIrqArch, MMArch, 12 }, 13 exception::InterruptArch, 14 ipc::{ 15 signal::set_current_sig_blocked, 16 signal_types::{SaHandlerType, SigInfo, Sigaction, SigactionType, SignalArch}, 17 }, 18 mm::MemoryManagementArch, 19 process::ProcessManager, 20 sched::{schedule, SchedMode}, 21 syscall::{user_access::UserBufferWriter, Syscall}, 22 }; 23 24 /// 信号处理的栈的栈指针的最小对齐数量 25 pub const STACK_ALIGN: u64 = 16; 26 /// 信号最大值 27 pub const MAX_SIG_NUM: usize = 64; 28 #[allow(dead_code)] 29 #[derive(Eq)] 30 #[repr(usize)] 31 #[allow(non_camel_case_types)] 32 #[atomic_enum] 33 pub enum Signal { 34 INVALID = 0, 35 SIGHUP = 1, 36 SIGINT, 37 SIGQUIT, 38 SIGILL, 39 SIGTRAP, 40 /// SIGABRT和SIGIOT共用这个号码 41 SIGABRT_OR_IOT, 42 SIGBUS, 43 SIGFPE, 44 SIGKILL, 45 SIGUSR1, 46 47 SIGSEGV = 11, 48 SIGUSR2, 49 SIGPIPE, 50 SIGALRM, 51 SIGTERM, 52 SIGSTKFLT, 53 SIGCHLD, 54 SIGCONT, 55 SIGSTOP, 56 SIGTSTP, 57 58 SIGTTIN = 21, 59 SIGTTOU, 60 SIGURG, 61 SIGXCPU, 62 SIGXFSZ, 63 SIGVTALRM, 64 SIGPROF, 65 SIGWINCH, 66 /// SIGIO和SIGPOLL共用这个号码 67 SIGIO_OR_POLL, 68 SIGPWR, 69 70 SIGSYS = 31, 71 72 SIGRTMIN = 32, 73 SIGRTMAX = 64, 74 } 75 76 /// 为Signal实现判断相等的trait 77 impl PartialEq for Signal { 78 fn eq(&self, other: &Signal) -> bool { 79 *self as usize == *other as usize 80 } 81 } 82 83 impl From<usize> for Signal { 84 fn from(value: usize) -> Self { 85 if value <= MAX_SIG_NUM { 86 let ret: Signal = unsafe { core::mem::transmute(value) }; 87 return ret; 88 } else { 89 error!("Try to convert an invalid number to Signal"); 90 return Signal::INVALID; 91 } 92 } 93 } 94 95 impl From<Signal> for usize { 96 fn from(val: Signal) -> Self { 97 val as usize 98 } 99 } 100 101 impl From<i32> for Signal { 102 fn from(value: i32) -> Self { 103 if value < 0 { 104 error!("Try to convert an invalid number to Signal"); 105 return Signal::INVALID; 106 } else { 107 return Self::from(value as usize); 108 } 109 } 110 } 111 112 impl From<Signal> for SigSet { 113 fn from(val: Signal) -> Self { 114 SigSet { 115 bits: (1 << (val as usize - 1) as u64), 116 } 117 } 118 } 119 impl Signal { 120 /// 判断一个数字是否为可用的信号 121 #[inline] 122 pub fn is_valid(&self) -> bool { 123 return (*self) as usize <= MAX_SIG_NUM; 124 } 125 126 /// const convertor between `Signal` and `SigSet` 127 pub const fn into_sigset(self) -> SigSet { 128 SigSet { 129 bits: (1 << (self as usize - 1) as u64), 130 } 131 } 132 133 /// 判断一个信号是不是实时信号 134 /// 135 /// ## 返回值 136 /// 137 /// - `true` 这个信号是实时信号 138 /// - `false` 这个信号不是实时信号 139 #[inline] 140 pub fn is_rt_signal(&self) -> bool { 141 return (*self) as usize >= Signal::SIGRTMIN.into(); 142 } 143 144 /// 调用信号的默认处理函数 145 pub fn handle_default(&self) { 146 match self { 147 Signal::INVALID => { 148 error!("attempting to handler an Invalid"); 149 } 150 Signal::SIGHUP => sig_terminate(*self), 151 Signal::SIGINT => sig_terminate(*self), 152 Signal::SIGQUIT => sig_terminate_dump(*self), 153 Signal::SIGILL => sig_terminate_dump(*self), 154 Signal::SIGTRAP => sig_terminate_dump(*self), 155 Signal::SIGABRT_OR_IOT => sig_terminate_dump(*self), 156 Signal::SIGBUS => sig_terminate_dump(*self), 157 Signal::SIGFPE => sig_terminate_dump(*self), 158 Signal::SIGKILL => sig_terminate(*self), 159 Signal::SIGUSR1 => sig_terminate(*self), 160 Signal::SIGSEGV => sig_terminate_dump(*self), 161 Signal::SIGUSR2 => sig_terminate(*self), 162 Signal::SIGPIPE => sig_terminate(*self), 163 Signal::SIGALRM => sig_terminate(*self), 164 Signal::SIGTERM => sig_terminate(*self), 165 Signal::SIGSTKFLT => sig_terminate(*self), 166 Signal::SIGCHLD => sig_ignore(*self), 167 Signal::SIGCONT => sig_continue(*self), 168 Signal::SIGSTOP => sig_stop(*self), 169 Signal::SIGTSTP => sig_stop(*self), 170 Signal::SIGTTIN => sig_stop(*self), 171 Signal::SIGTTOU => sig_stop(*self), 172 Signal::SIGURG => sig_ignore(*self), 173 Signal::SIGXCPU => sig_terminate_dump(*self), 174 Signal::SIGXFSZ => sig_terminate_dump(*self), 175 Signal::SIGVTALRM => sig_terminate(*self), 176 Signal::SIGPROF => sig_terminate(*self), 177 Signal::SIGWINCH => sig_ignore(*self), 178 Signal::SIGIO_OR_POLL => sig_terminate(*self), 179 Signal::SIGPWR => sig_terminate(*self), 180 Signal::SIGSYS => sig_terminate(*self), 181 Signal::SIGRTMIN => sig_terminate(*self), 182 Signal::SIGRTMAX => sig_terminate(*self), 183 } 184 } 185 } 186 187 /// siginfo中的si_code的可选值 188 /// 请注意，当这个值小于0时，表示siginfo来自用户态，否则来自内核态 189 #[derive(Copy, Debug, Clone)] 190 #[repr(i32)] 191 pub enum SigCode { 192 /// sent by kill, sigsend, raise 193 User = 0, 194 /// sent by kernel from somewhere 195 Kernel = 0x80, 196 /// 通过sigqueue发送 197 Queue = -1, 198 /// 定时器过期时发送 199 Timer = -2, 200 /// 当实时消息队列的状态发生改变时发送 201 Mesgq = -3, 202 /// 当异步IO完成时发送 203 AsyncIO = -4, 204 /// sent by queued SIGIO 205 SigIO = -5, 206 } 207 208 impl SigCode { 209 /// 为SigCode这个枚举类型实现从i32转换到枚举类型的转换函数 210 #[allow(dead_code)] 211 pub fn from_i32(x: i32) -> SigCode { 212 match x { 213 0 => Self::User, 214 0x80 => Self::Kernel, 215 -1 => Self::Queue, 216 -2 => Self::Timer, 217 -3 => Self::Mesgq, 218 -4 => Self::AsyncIO, 219 -5 => Self::SigIO, 220 _ => panic!("signal code not valid"), 221 } 222 } 223 } 224 225 bitflags! { 226 #[repr(C,align(8))] 227 #[derive(Default)] 228 pub struct SigFlags:u32{ 229 const SA_NOCLDSTOP = 1; 230 const SA_NOCLDWAIT = 2; 231 const SA_SIGINFO = 4; 232 const SA_ONSTACK = 0x08000000; 233 const SA_RESTART = 0x10000000; 234 const SA_NODEFER = 0x40000000; 235 const SA_RESETHAND = 0x80000000; 236 const SA_RESTORER =0x04000000; 237 const SA_ALL = Self::SA_NOCLDSTOP.bits()|Self::SA_NOCLDWAIT.bits()|Self::SA_NODEFER.bits()|Self::SA_ONSTACK.bits()|Self::SA_RESETHAND.bits()|Self::SA_RESTART.bits()|Self::SA_SIGINFO.bits()|Self::SA_RESTORER.bits(); 238 } 239 240 /// 请注意，sigset 这个bitmap, 第0位表示sig=1的信号。也就是说，Signal-1才是sigset_t中对应的位 241 #[derive(Default)] 242 pub struct SigSet:u64{ 243 const SIGHUP = 1<<0; 244 const SIGINT = 1<<1; 245 const SIGQUIT = 1<<2; 246 const SIGILL = 1<<3; 247 const SIGTRAP = 1<<4; 248 /// SIGABRT和SIGIOT共用这个号码 249 const SIGABRT_OR_IOT = 1<<5; 250 const SIGBUS = 1<<6; 251 const SIGFPE = 1<<7; 252 const SIGKILL = 1<<8; 253 const SIGUSR = 1<<9; 254 const SIGSEGV = 1<<10; 255 const SIGUSR2 = 1<<11; 256 const SIGPIPE = 1<<12; 257 const SIGALRM = 1<<13; 258 const SIGTERM = 1<<14; 259 const SIGSTKFLT= 1<<15; 260 const SIGCHLD = 1<<16; 261 const SIGCONT = 1<<17; 262 const SIGSTOP = 1<<18; 263 const SIGTSTP = 1<<19; 264 const SIGTTIN = 1<<20; 265 const SIGTTOU = 1<<21; 266 const SIGURG = 1<<22; 267 const SIGXCPU = 1<<23; 268 const SIGXFSZ = 1<<24; 269 const SIGVTALRM= 1<<25; 270 const SIGPROF = 1<<26; 271 const SIGWINCH = 1<<27; 272 /// SIGIO和SIGPOLL共用这个号码 273 const SIGIO_OR_POLL = 1<<28; 274 const SIGPWR = 1<<29; 275 const SIGSYS = 1<<30; 276 const SIGRTMIN = 1<<31; 277 // TODO 写上实时信号 278 const SIGRTMAX = 1 << (MAX_SIG_NUM-1); 279 } 280 } 281 282 /// SIGCHLD si_codes 283 #[derive(Debug, Clone, Copy, PartialEq, Eq, ToPrimitive)] 284 #[allow(dead_code)] 285 pub enum SigChildCode { 286 /// child has exited 287 /// 288 /// CLD_EXITED 289 Exited = 1, 290 /// child was killed 291 /// 292 /// CLD_KILLED 293 Killed = 2, 294 /// child terminated abnormally 295 /// 296 /// CLD_DUMPED 297 Dumped = 3, 298 /// traced child has trapped 299 /// 300 /// CLD_TRAPPED 301 Trapped = 4, 302 /// child has stopped 303 /// 304 /// CLD_STOPPED 305 Stopped = 5, 306 /// stopped child has continued 307 /// 308 /// CLD_CONTINUED 309 Continued = 6, 310 } 311 312 impl From<SigChildCode> for i32 { 313 fn from(value: SigChildCode) -> Self { 314 value as i32 315 } 316 } 317 318 #[repr(C, align(16))] 319 #[derive(Debug, Clone, Copy)] 320 pub struct SigFrame { 321 // pub pedding: u64, 322 /// 指向restorer的地址的指针。（该变量必须放在sigframe的第一位，因为这样才能在handler返回的时候，跳转到对应的代码，执行sigreturn) 323 pub ret_code_ptr: *mut core::ffi::c_void, 324 pub handler: *mut c_void, 325 pub info: SigInfo, 326 pub context: SigContext, 327 } 328 329 #[repr(C, align(16))] 330 #[derive(Debug, Clone, Copy)] 331 pub struct SigContext { 332 /// sigcontext的标志位 333 pub sc_flags: u64, 334 pub sc_stack: SigStack, // 信号处理程序备用栈信息 335 pub frame: TrapFrame, // 暂存的系统调用/中断返回时，原本要弹出的内核栈帧 336 // pub trap_num: u64, // 用来保存线程结构体中的trap_num字段 337 pub oldmask: SigSet, // 暂存的执行信号处理函数之前的，被设置block的信号 338 pub cr2: u64, // 用来保存线程结构体中的cr2字段 339 // pub err_code: u64, // 用来保存线程结构体中的err_code字段 340 pub reserved_for_x87_state: Option<FpState>, 341 pub reserved: [u64; 8], 342 } 343 344 impl SigContext { 345 /// 设置sigcontext 346 /// 347 /// ## 参数 348 /// 349 /// - `mask` 要被暂存的信号mask标志位 350 /// - `regs` 进入信号处理流程前，Restore all要弹出的内核栈栈帧 351 /// 352 /// ## 返回值 353 /// 354 /// - `Ok(0)` 355 /// - `Err(Systemerror)` (暂时不会返回错误) 356 pub fn setup_sigcontext( 357 &mut self, 358 mask: &SigSet, 359 frame: &TrapFrame, 360 ) -> Result<i32, SystemError> { 361 //TODO 引入线程后补上 362 // let current_thread = ProcessManager::current_pcb().thread; 363 let pcb = ProcessManager::current_pcb(); 364 let mut archinfo_guard = pcb.arch_info_irqsave(); 365 self.oldmask = *mask; 366 self.frame = *frame; 367 // context.trap_num = unsafe { (*current_thread).trap_num }; 368 // context.err_code = unsafe { (*current_thread).err_code }; 369 // context.cr2 = unsafe { (*current_thread).cr2 }; 370 self.reserved_for_x87_state = *archinfo_guard.fp_state(); 371 372 // 保存完毕后，清空fp_state，以免下次save的时候，出现SIMD exception 373 archinfo_guard.clear_fp_state(); 374 return Ok(0); 375 } 376 377 /// 指定的sigcontext恢复到当前进程的内核栈帧中,并将当前线程结构体的几个参数进行恢复 378 /// 379 /// ## 参数 380 /// - `frame` 目标栈帧（也就是把context恢复到这个栈帧中） 381 /// 382 /// ##返回值 383 /// - `true` -> 成功恢复 384 /// - `false` -> 执行失败 385 pub fn restore_sigcontext(&mut self, frame: &mut TrapFrame) -> bool { 386 let guard = ProcessManager::current_pcb(); 387 let mut arch_info = guard.arch_info_irqsave(); 388 (*frame) = self.frame; 389 // (*current_thread).trap_num = (*context).trap_num; 390 *arch_info.cr2_mut() = self.cr2 as usize; 391 // (*current_thread).err_code = (*context).err_code; 392 // 如果当前进程有fpstate，则将其恢复到pcb的fp_state中 393 *arch_info.fp_state_mut() = self.reserved_for_x87_state; 394 arch_info.restore_fp_state(); 395 return true; 396 } 397 } 398 /// @brief 信号处理备用栈的信息 399 #[allow(dead_code)] 400 #[derive(Debug, Clone, Copy)] 401 pub struct SigStack { 402 pub sp: *mut c_void, 403 pub flags: u32, 404 pub size: u32, 405 pub fpstate: FpState, 406 } 407 408 #[no_mangle] 409 unsafe extern "C" fn do_signal(frame: &mut TrapFrame) { 410 X86_64SignalArch::do_signal(frame); 411 return; 412 } 413 414 pub struct X86_64SignalArch; 415 416 impl SignalArch for X86_64SignalArch { 417 unsafe fn do_signal(frame: &mut TrapFrame) { 418 let pcb = ProcessManager::current_pcb(); 419 420 let siginfo = pcb.try_siginfo_irqsave(5); 421 422 if unlikely(siginfo.is_none()) { 423 return; 424 } 425 426 let siginfo_read_guard = siginfo.unwrap(); 427 428 // 检查sigpending是否为0 429 if siginfo_read_guard.sig_pending().signal().bits() == 0 || !frame.is_from_user() { 430 // 若没有正在等待处理的信号，或者将要返回到的是内核态，则返回 431 return; 432 } 433 434 let pcb = ProcessManager::current_pcb(); 435 436 let mut sig_number: Signal; 437 let mut info: Option<SigInfo>; 438 let mut sigaction: Sigaction; 439 let sig_block: SigSet = *siginfo_read_guard.sig_block(); 440 drop(siginfo_read_guard); 441 442 let sig_guard = pcb.try_sig_struct_irqsave(5); 443 if unlikely(sig_guard.is_none()) { 444 return; 445 } 446 let siginfo_mut = pcb.try_siginfo_mut(5); 447 if unlikely(siginfo_mut.is_none()) { 448 return; 449 } 450 451 let sig_guard = sig_guard.unwrap(); 452 let mut siginfo_mut_guard = siginfo_mut.unwrap(); 453 loop { 454 (sig_number, info) = siginfo_mut_guard.dequeue_signal(&sig_block); 455 // 如果信号非法，则直接返回 456 if sig_number == Signal::INVALID { 457 return; 458 } 459 460 sigaction = sig_guard.handlers[sig_number as usize - 1]; 461 462 match sigaction.action() { 463 SigactionType::SaHandler(action_type) => match action_type { 464 SaHandlerType::Error => { 465 error!("Trying to handle a Sigerror on Process:{:?}", pcb.pid()); 466 return; 467 } 468 SaHandlerType::Default => { 469 sigaction = Sigaction::default(); 470 break; 471 } 472 SaHandlerType::Ignore => continue, 473 SaHandlerType::Customized(_) => { 474 break; 475 } 476 }, 477 SigactionType::SaSigaction(_) => todo!(), 478 } 479 // 如果当前动作是忽略这个信号，就继续循环。 480 } 481 482 let oldset = *siginfo_mut_guard.sig_block(); 483 //避免死锁 484 drop(siginfo_mut_guard); 485 drop(sig_guard); 486 487 // 做完上面的检查后，开中断 488 CurrentIrqArch::interrupt_enable(); 489 let res: Result<i32, SystemError> = 490 handle_signal(sig_number, &mut sigaction, &info.unwrap(), &oldset, frame); 491 if res.is_err() { 492 error!( 493 "Error occurred when handling signal: {}, pid={:?}, errcode={:?}", 494 sig_number as i32, 495 ProcessManager::current_pcb().pid(), 496 res.as_ref().unwrap_err() 497 ); 498 } 499 } 500 501 fn sys_rt_sigreturn(trap_frame: &mut TrapFrame) -> u64 { 502 let frame = (trap_frame.rsp as usize - size_of::<u64>()) as *mut SigFrame; 503 504 // 如果当前的rsp不来自用户态，则认为产生了错误（或被SROP攻击） 505 if UserBufferWriter::new(frame, size_of::<SigFrame>(), true).is_err() { 506 error!("rsp doesn't from user level"); 507 let _r = Syscall::kill(ProcessManager::current_pcb().pid(), Signal::SIGSEGV as i32) 508 .map_err(|e| e.to_posix_errno()); 509 return trap_frame.rax; 510 } 511 let mut sigmask: SigSet = unsafe { (*frame).context.oldmask }; 512 set_current_sig_blocked(&mut sigmask); 513 // 从用户栈恢复sigcontext 514 if !unsafe { &mut (*frame).context }.restore_sigcontext(trap_frame) { 515 error!("unable to restore sigcontext"); 516 let _r = Syscall::kill(ProcessManager::current_pcb().pid(), Signal::SIGSEGV as i32) 517 .map_err(|e| e.to_posix_errno()); 518 // 如果这里返回 err 值的话会丢失上一个系统调用的返回值 519 } 520 // 由于系统调用的返回值会被系统调用模块被存放在rax寄存器，因此，为了还原原来的那个系统调用的返回值，我们需要在这里返回恢复后的rax的值 521 return trap_frame.rax; 522 } 523 } 524 525 /// @brief 真正发送signal，执行自定义的处理函数 526 /// 527 /// @param sig 信号number 528 /// @param sigaction 信号响应动作 529 /// @param info 信号信息 530 /// @param oldset 531 /// @param regs 之前的系统调用将要返回的时候，要弹出的栈帧的拷贝 532 /// 533 /// @return Result<0,SystemError> 若Error, 则返回错误码,否则返回Ok(0) 534 fn handle_signal( 535 sig: Signal, 536 sigaction: &mut Sigaction, 537 info: &SigInfo, 538 oldset: &SigSet, 539 frame: &mut TrapFrame, 540 ) -> Result<i32, SystemError> { 541 // TODO 这里要补充一段逻辑，好像是为了保证引入线程之后的地址空间不会出问题。详见https://code.dragonos.org.cn/xref/linux-6.1.9/arch/mips/kernel/signal.c#830 542 543 // 设置栈帧 544 return setup_frame(sig, sigaction, info, oldset, frame); 545 } 546 547 /// @brief 在用户栈上开辟一块空间，并且把内核栈的栈帧以及需要在用户态执行的代码给保存进去。 548 /// 549 /// @param regs 进入信号处理流程前，Restore all要弹出的内核栈栈帧 550 fn setup_frame( 551 sig: Signal, 552 sigaction: &mut Sigaction, 553 info: &SigInfo, 554 oldset: &SigSet, 555 trap_frame: &mut TrapFrame, 556 ) -> Result<i32, SystemError> { 557 let ret_code_ptr: *mut c_void; 558 let temp_handler: *mut c_void; 559 match sigaction.action() { 560 SigactionType::SaHandler(handler_type) => match handler_type { 561 SaHandlerType::Default => { 562 sig.handle_default(); 563 return Ok(0); 564 } 565 SaHandlerType::Customized(handler) => { 566 // 如果handler位于内核空间 567 if handler >= MMArch::USER_END_VADDR { 568 // 如果当前是SIGSEGV,则采用默认函数处理 569 if sig == Signal::SIGSEGV { 570 sig.handle_default(); 571 return Ok(0); 572 } else { 573 error!("attempting to execute a signal handler from kernel"); 574 sig.handle_default(); 575 return Err(SystemError::EINVAL); 576 } 577 } else { 578 // 为了与Linux的兼容性，64位程序必须由用户自行指定restorer 579 if sigaction.flags().contains(SigFlags::SA_RESTORER) { 580 ret_code_ptr = sigaction.restorer().unwrap().data() as *mut c_void; 581 } else { 582 error!( 583 "pid-{:?} forgot to set SA_FLAG_RESTORER for signal {:?}", 584 ProcessManager::current_pcb().pid(), 585 sig as i32 586 ); 587 let r = Syscall::kill( 588 ProcessManager::current_pcb().pid(), 589 Signal::SIGSEGV as i32, 590 ); 591 if r.is_err() { 592 error!("In setup_sigcontext: generate SIGSEGV signal failed"); 593 } 594 return Err(SystemError::EINVAL); 595 } 596 if sigaction.restorer().is_none() { 597 error!( 598 "restorer in process:{:?} is not defined", 599 ProcessManager::current_pcb().pid() 600 ); 601 return Err(SystemError::EINVAL); 602 } 603 temp_handler = handler.data() as *mut c_void; 604 } 605 } 606 SaHandlerType::Ignore => { 607 return Ok(0); 608 } 609 _ => { 610 return Err(SystemError::EINVAL); 611 } 612 }, 613 SigactionType::SaSigaction(_) => { 614 //TODO 这里应该是可以恢复栈的，等后续来做 615 error!("trying to recover from sigaction type instead of handler"); 616 return Err(SystemError::EINVAL); 617 } 618 } 619 let frame: *mut SigFrame = get_stack(trap_frame, size_of::<SigFrame>()); 620 // debug!("frame=0x{:016x}", frame as usize); 621 // 要求这个frame的地址位于用户空间，因此进行校验 622 let r: Result<UserBufferWriter<'_>, SystemError> = 623 UserBufferWriter::new(frame, size_of::<SigFrame>(), true); 624 if r.is_err() { 625 // 如果地址区域位于内核空间，则直接报错 626 // todo: 生成一个sigsegv 627 let r = Syscall::kill(ProcessManager::current_pcb().pid(), Signal::SIGSEGV as i32); 628 if r.is_err() { 629 error!("In setup frame: generate SIGSEGV signal failed"); 630 } 631 error!("In setup frame: access check failed"); 632 return Err(SystemError::EFAULT); 633 } 634 635 // 将siginfo拷贝到用户栈 636 info.copy_siginfo_to_user(unsafe { &mut ((*frame).info) as *mut SigInfo }) 637 .map_err(|e| -> SystemError { 638 let r = Syscall::kill(ProcessManager::current_pcb().pid(), Signal::SIGSEGV as i32); 639 if r.is_err() { 640 error!("In copy_siginfo_to_user: generate SIGSEGV signal failed"); 641 } 642 return e; 643 })?; 644 645 // todo: 拷贝处理程序备用栈的地址、大小、ss_flags 646 647 unsafe { 648 (*frame) 649 .context 650 .setup_sigcontext(oldset, trap_frame) 651 .map_err(|e: SystemError| -> SystemError { 652 let r = Syscall::kill(ProcessManager::current_pcb().pid(), Signal::SIGSEGV as i32); 653 if r.is_err() { 654 error!("In setup_sigcontext: generate SIGSEGV signal failed"); 655 } 656 return e; 657 })? 658 }; 659 660 unsafe { 661 // 在开头检验过sigaction.restorer是否为空了，实际上libc会保证 restorer始终不为空 662 (*frame).ret_code_ptr = ret_code_ptr; 663 } 664 665 unsafe { (*frame).handler = temp_handler }; 666 // 传入信号处理函数的第一个参数 667 trap_frame.rdi = sig as u64; 668 trap_frame.rsi = unsafe { &(*frame).info as *const SigInfo as u64 }; 669 trap_frame.rsp = frame as u64; 670 trap_frame.rip = unsafe { (*frame).handler as u64 }; 671 // 设置cs和ds寄存器 672 trap_frame.cs = (USER_CS.bits() | 0x3) as u64; 673 trap_frame.ds = (USER_DS.bits() | 0x3) as u64; 674 675 // 禁用中断 676 // trap_frame.rflags &= !(0x200); 677 678 return Ok(0); 679 } 680 681 #[inline(always)] 682 fn get_stack(frame: &TrapFrame, size: usize) -> *mut SigFrame { 683 // TODO:在 linux 中会根据 Sigaction 中的一个flag 的值来确定是否使用pcb中的 signal 处理程序备用堆栈，现在的 684 // pcb中也没有这个备用堆栈 685 686 // 默认使用 用户栈的栈顶指针-128字节的红区-sigframe的大小 并且16字节对齐 687 let mut rsp: usize = (frame.rsp as usize) - 128 - size; 688 // 按照要求进行对齐，别问为什么减8，不减8就是错的，可以看 689 // https://sourcegraph.com/github.com/torvalds/linux@dd72f9c7e512da377074d47d990564959b772643/-/blob/arch/x86/kernel/signal.c?L124 690 // 我猜测是跟x86汇编的某些弹栈行为有关系，它可能会出于某种原因递增 rsp 691 rsp &= (!(STACK_ALIGN - 1)) as usize - 8; 692 // rsp &= (!(STACK_ALIGN - 1)) as usize; 693 return rsp as *mut SigFrame; 694 } 695 696 /// 信号默认处理函数——终止进程 697 fn sig_terminate(sig: Signal) { 698 ProcessManager::exit(sig as usize); 699 } 700 701 /// 信号默认处理函数——终止进程并生成 core dump 702 fn sig_terminate_dump(sig: Signal) { 703 ProcessManager::exit(sig as usize); 704 // TODO 生成 coredump 文件 705 } 706 707 /// 信号默认处理函数——暂停进程 708 fn sig_stop(sig: Signal) { 709 let guard = unsafe { CurrentIrqArch::save_and_disable_irq() }; 710 ProcessManager::mark_stop().unwrap_or_else(|e| { 711 error!( 712 "sleep error :{:?},failed to sleep process :{:?}, with signal :{:?}", 713 e, 714 ProcessManager::current_pcb(), 715 sig 716 ); 717 }); 718 drop(guard); 719 schedule(SchedMode::SM_NONE); 720 // TODO 暂停进程 721 } 722 /// 信号默认处理函数——继续进程 723 fn sig_continue(sig: Signal) { 724 ProcessManager::wakeup_stop(&ProcessManager::current_pcb()).unwrap_or_else(|_| { 725 error!( 726 "Failed to wake up process pid = {:?} with signal :{:?}", 727 ProcessManager::current_pcb().pid(), 728 sig 729 ); 730 }); 731 } 732 /// 信号默认处理函数——忽略 733 fn sig_ignore(_sig: Signal) { 734 return; 735 } 736