/* * linux/arch/i386/kernel/signal.c * * Copyright (C) 1991, 1992 Linus Torvalds * * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson * 2000-05-25 Pentium III FXSR, SSE support by Gareth Hughes */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define DEBUG_SIG 0 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP))) asmlinkage int sys_wait4(pid_t pid, unsigned long *stat_addr, int options, unsigned long *ru); asmlinkage int FASTCALL(do_signal(struct pt_regs *regs, sigset_t *oldset)); int copy_siginfo_to_user(siginfo_t *to, siginfo_t *from) { if (!access_ok (VERIFY_WRITE, to, sizeof(siginfo_t))) return -EFAULT; if (from->si_code < 0) return __copy_to_user(to, from, sizeof(siginfo_t)); else { int err; /* If you change siginfo_t structure, please be sure this code is fixed accordingly. It should never copy any pad contained in the structure to avoid security leaks, but must copy the generic 3 ints plus the relevant union member. */ err = __put_user(from->si_signo, &to->si_signo); err |= __put_user(from->si_errno, &to->si_errno); err |= __put_user((short)from->si_code, &to->si_code); /* First 32bits of unions are always present. */ err |= __put_user(from->si_pid, &to->si_pid); switch (from->si_code >> 16) { case __SI_FAULT >> 16: break; case __SI_CHLD >> 16: err |= __put_user(from->si_utime, &to->si_utime); err |= __put_user(from->si_stime, &to->si_stime); err |= __put_user(from->si_status, &to->si_status); default: err |= __put_user(from->si_uid, &to->si_uid); break; /* case __SI_RT: This is not generated by the kernel as of now. */ } return err; } } /* * Atomically swap in the new signal mask, and wait for a signal. */ asmlinkage int sys_sigsuspend(int history0, int history1, old_sigset_t mask) { struct pt_regs * regs = (struct pt_regs *) &history0; sigset_t saveset; mask &= _BLOCKABLE; spin_lock_irq(¤t->sigmask_lock); saveset = current->blocked; siginitset(¤t->blocked, mask); recalc_sigpending(current); spin_unlock_irq(¤t->sigmask_lock); regs->eax = -EINTR; while (1) { current->state = TASK_INTERRUPTIBLE; schedule(); if (do_signal(regs, &saveset)) return -EINTR; } } asmlinkage int sys_rt_sigsuspend(sigset_t *unewset, size_t sigsetsize) { struct pt_regs * regs = (struct pt_regs *) &unewset; sigset_t saveset, newset; /* XXX: Don't preclude handling different sized sigset_t's. */ if (sigsetsize != sizeof(sigset_t)) return -EINVAL; if (copy_from_user(&newset, unewset, sizeof(newset))) return -EFAULT; sigdelsetmask(&newset, ~_BLOCKABLE); spin_lock_irq(¤t->sigmask_lock); saveset = current->blocked; current->blocked = newset; recalc_sigpending(current); spin_unlock_irq(¤t->sigmask_lock); regs->eax = -EINTR; while (1) { current->state = TASK_INTERRUPTIBLE; schedule(); if (do_signal(regs, &saveset)) return -EINTR; } } asmlinkage int sys_sigaction(int sig, const struct old_sigaction *act, struct old_sigaction *oact) { struct k_sigaction new_ka, old_ka; int ret; if (act) { old_sigset_t mask; if (verify_area(VERIFY_READ, act, sizeof(*act)) || __get_user(new_ka.sa.sa_handler, &act->sa_handler) || __get_user(new_ka.sa.sa_restorer, &act->sa_restorer)) return -EFAULT; __get_user(new_ka.sa.sa_flags, &act->sa_flags); __get_user(mask, &act->sa_mask); siginitset(&new_ka.sa.sa_mask, mask); } ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL); if (!ret && oact) { if (verify_area(VERIFY_WRITE, oact, sizeof(*oact)) || __put_user(old_ka.sa.sa_handler, &oact->sa_handler) || __put_user(old_ka.sa.sa_restorer, &oact->sa_restorer)) return -EFAULT; __put_user(old_ka.sa.sa_flags, &oact->sa_flags); __put_user(old_ka.sa.sa_mask.sig[0], &oact->sa_mask); } return ret; } asmlinkage int sys_sigaltstack(const stack_t *uss, stack_t *uoss) { struct pt_regs *regs = (struct pt_regs *) &uss; return do_sigaltstack(uss, uoss, regs->esp); } /* * Do a signal return; undo the signal stack. */ struct sigframe { char *pretcode; int sig; struct sigcontext sc; struct _fpstate fpstate; unsigned long extramask[_NSIG_WORDS-1]; char retcode[8]; }; struct rt_sigframe { char *pretcode; int sig; struct siginfo *pinfo; void *puc; struct siginfo info; struct ucontext uc; struct _fpstate fpstate; char retcode[8]; }; static inline int restore_i387_hard(struct _fpstate *buf) { struct task_struct *tsk = current; #ifdef CONFIG_X86_FXSR struct _fpreg *from; struct _fpxreg *to; int i; #endif clear_fpu(tsk); #ifdef CONFIG_X86_FXSR if (__copy_from_user(&tsk->thread.i387.hard, buf, 7 * sizeof(long))) return 1; from = &buf->_st[0]; to = (struct _fpxreg *) &tsk->thread.i387.hard.st_space[0]; for (i = 0; i < 8; i++, to++, from++) { if (__copy_from_user(to, from, sizeof(*from))) return 1; } if (__copy_from_user(&tsk->thread.i387.hard.fxsr_space[0], &buf->_fxsr_env[0], X86_FXSR_SIZE)) return 1; #else if (__copy_from_user(&tsk->thread.i387.hard, buf, sizeof(struct i387_hard_struct))) return 1; #endif return 0; } static inline int restore_i387(struct _fpstate *buf) { int err; #ifndef CONFIG_MATH_EMULATION err = restore_i387_hard(buf); #else if (boot_cpu_data.hard_math) err = restore_i387_hard(buf); else err = restore_i387_soft(¤t->thread.i387.soft, buf); #endif current->used_math = 1; return err; } static int restore_sigcontext(struct pt_regs *regs, struct sigcontext *sc, int *peax) { unsigned int err = 0; #define COPY(x) err |= __get_user(regs->x, &sc->x) #define COPY_SEG(seg) \ { unsigned short tmp; \ err |= __get_user(tmp, &sc->seg); \ regs->x##seg = tmp; } #define COPY_SEG_STRICT(seg) \ { unsigned short tmp; \ err |= __get_user(tmp, &sc->seg); \ regs->x##seg = tmp|3; } #define GET_SEG(seg) \ { unsigned short tmp; \ err |= __get_user(tmp, &sc->seg); \ loadsegment(seg,tmp); } GET_SEG(gs); GET_SEG(fs); COPY_SEG(es); COPY_SEG(ds); COPY(edi); COPY(esi); COPY(ebp); COPY(esp); COPY(ebx); COPY(edx); COPY(ecx); COPY(eip); COPY_SEG_STRICT(cs); COPY_SEG_STRICT(ss); { unsigned int tmpflags; err |= __get_user(tmpflags, &sc->eflags); regs->eflags = (regs->eflags & ~0x40DD5) | (tmpflags & 0x40DD5); regs->orig_eax = -1; /* disable syscall checks */ } { struct _fpstate * buf; err |= __get_user(buf, &sc->fpstate); if (buf) { if (verify_area(VERIFY_READ, buf, sizeof(*buf))) goto badframe; err |= restore_i387(buf); } } err |= __get_user(*peax, &sc->eax); return err; badframe: return 1; } asmlinkage int sys_sigreturn(unsigned long __unused) { struct pt_regs *regs = (struct pt_regs *) &__unused; struct sigframe *frame = (struct sigframe *)(regs->esp - 8); sigset_t set; int eax; if (verify_area(VERIFY_READ, frame, sizeof(*frame))) goto badframe; if (__get_user(set.sig[0], &frame->sc.oldmask) || (_NSIG_WORDS > 1 && __copy_from_user(&set.sig[1], &frame->extramask, sizeof(frame->extramask)))) goto badframe; sigdelsetmask(&set, ~_BLOCKABLE); spin_lock_irq(¤t->sigmask_lock); current->blocked = set; recalc_sigpending(current); spin_unlock_irq(¤t->sigmask_lock); if (restore_sigcontext(regs, &frame->sc, &eax)) goto badframe; return eax; badframe: force_sig(SIGSEGV, current); return 0; } asmlinkage int sys_rt_sigreturn(unsigned long __unused) { struct pt_regs *regs = (struct pt_regs *) &__unused; struct rt_sigframe *frame = (struct rt_sigframe *)(regs->esp - 4); sigset_t set; stack_t st; int eax; if (verify_area(VERIFY_READ, frame, sizeof(*frame))) goto badframe; if (__copy_from_user(&set, &frame->uc.uc_sigmask, sizeof(set))) goto badframe; sigdelsetmask(&set, ~_BLOCKABLE); spin_lock_irq(¤t->sigmask_lock); current->blocked = set; recalc_sigpending(current); spin_unlock_irq(¤t->sigmask_lock); if (restore_sigcontext(regs, &frame->uc.uc_mcontext, &eax)) goto badframe; if (__copy_from_user(&st, &frame->uc.uc_stack, sizeof(st))) goto badframe; /* It is more difficult to avoid calling this function than to call it and ignore errors. */ do_sigaltstack(&st, NULL, regs->esp); return eax; badframe: force_sig(SIGSEGV, current); return 0; } /* * Set up a signal frame. */ static inline int save_i387_hard(struct _fpstate * buf) { struct task_struct *tsk = current; #ifdef CONFIG_X86_FXSR struct _fpreg *to; struct _fpxreg *from; int i; int err = 0; #endif unlazy_fpu(tsk); tsk->thread.i387.hard.status = tsk->thread.i387.hard.swd; #ifdef CONFIG_X86_FXSR if (__copy_to_user(buf, &tsk->thread.i387.hard, 7 * sizeof(long))) return -1; to = &buf->_st[0]; from = (struct _fpxreg *) &tsk->thread.i387.hard.st_space[0]; for (i = 0; i < 8; i++, to++, from++) { if (__copy_to_user(to, from, sizeof(*to))) return -1; } err |= __put_user(tsk->thread.i387.hard.swd & 0xffff, &buf->status); err |= __put_user(X86_FXSR_MAGIC, &buf->magic); if (err) return -1; if (__copy_to_user(&buf->_fxsr_env[0], &tsk->thread.i387.hard.fxsr_space[0], X86_FXSR_SIZE)) return -1; #else if (__copy_to_user(buf, &tsk->thread.i387.hard, sizeof(struct i387_hard_struct))) return -1; #endif return 1; } static int save_i387(struct _fpstate *buf) { if (!current->used_math) return 0; /* This will cause a "finit" to be triggered by the next attempted FPU operation by the 'current' process. */ current->used_math = 0; #ifndef CONFIG_MATH_EMULATION return save_i387_hard(buf); #else return boot_cpu_data.hard_math ? save_i387_hard(buf) : save_i387_soft(¤t->thread.i387.soft, buf); #endif } static int setup_sigcontext(struct sigcontext *sc, struct _fpstate *fpstate, struct pt_regs *regs, unsigned long mask) { int tmp, err = 0; tmp = 0; __asm__("movl %%gs,%0" : "=r"(tmp): "0"(tmp)); err |= __put_user(tmp, (unsigned int *)&sc->gs); __asm__("movl %%fs,%0" : "=r"(tmp): "0"(tmp)); err |= __put_user(tmp, (unsigned int *)&sc->fs); err |= __put_user(regs->xes, (unsigned int *)&sc->es); err |= __put_user(regs->xds, (unsigned int *)&sc->ds); err |= __put_user(regs->edi, &sc->edi); err |= __put_user(regs->esi, &sc->esi); err |= __put_user(regs->ebp, &sc->ebp); err |= __put_user(regs->esp, &sc->esp); err |= __put_user(regs->ebx, &sc->ebx); err |= __put_user(regs->edx, &sc->edx); err |= __put_user(regs->ecx, &sc->ecx); err |= __put_user(regs->eax, &sc->eax); err |= __put_user(current->thread.trap_no, &sc->trapno); err |= __put_user(current->thread.error_code, &sc->err); err |= __put_user(regs->eip, &sc->eip); err |= __put_user(regs->xcs, (unsigned int *)&sc->cs); err |= __put_user(regs->eflags, &sc->eflags); err |= __put_user(regs->esp, &sc->esp_at_signal); err |= __put_user(regs->xss, (unsigned int *)&sc->ss); tmp = save_i387(fpstate); if (tmp < 0) err = 1; else err |= __put_user(tmp ? fpstate : NULL, &sc->fpstate); /* non-iBCS2 extensions.. */ err |= __put_user(mask, &sc->oldmask); err |= __put_user(current->thread.cr2, &sc->cr2); return err; } /* * Determine which stack to use.. */ static inline void * get_sigframe(struct k_sigaction *ka, struct pt_regs * regs, size_t frame_size) { unsigned long esp; /* Default to using normal stack */ esp = regs->esp; /* This is the X/Open sanctioned signal stack switching. */ if (ka->sa.sa_flags & SA_ONSTACK) { if (! on_sig_stack(esp)) esp = current->sas_ss_sp + current->sas_ss_size; } /* This is the legacy signal stack switching. */ else if ((regs->xss & 0xffff) != __USER_DS && !(ka->sa.sa_flags & SA_RESTORER) && ka->sa.sa_restorer) { esp = (unsigned long) ka->sa.sa_restorer; } return (void *)((esp - frame_size) & -8ul); } static void setup_frame(int sig, struct k_sigaction *ka, sigset_t *set, struct pt_regs * regs) { struct sigframe *frame; int err = 0; frame = get_sigframe(ka, regs, sizeof(*frame)); if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) goto give_sigsegv; err |= __put_user((current->exec_domain && current->exec_domain->signal_invmap && sig < 32 ? current->exec_domain->signal_invmap[sig] : sig), &frame->sig); if (err) goto give_sigsegv; err |= setup_sigcontext(&frame->sc, &frame->fpstate, regs, set->sig[0]); if (err) goto give_sigsegv; if (_NSIG_WORDS > 1) { err |= __copy_to_user(frame->extramask, &set->sig[1], sizeof(frame->extramask)); } if (err) goto give_sigsegv; /* Set up to return from userspace. If provided, use a stub already in userspace. */ if (ka->sa.sa_flags & SA_RESTORER) { err |= __put_user(ka->sa.sa_restorer, &frame->pretcode); } else { err |= __put_user(frame->retcode, &frame->pretcode); /* This is popl %eax ; movl $,%eax ; int $0x80 */ err |= __put_user(0xb858, (short *)(frame->retcode+0)); err |= __put_user(__NR_sigreturn, (int *)(frame->retcode+2)); err |= __put_user(0x80cd, (short *)(frame->retcode+6)); } if (err) goto give_sigsegv; /* Set up registers for signal handler */ regs->esp = (unsigned long) frame; regs->eip = (unsigned long) ka->sa.sa_handler; set_fs(USER_DS); regs->xds = __USER_DS; regs->xes = __USER_DS; regs->xss = __USER_DS; regs->xcs = __USER_CS; regs->eflags &= ~TF_MASK; #if DEBUG_SIG printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n", current->comm, current->pid, frame, regs->eip, frame->pretcode); #endif return; give_sigsegv: if (sig == SIGSEGV) ka->sa.sa_handler = SIG_DFL; force_sig(SIGSEGV, current); } static void setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info, sigset_t *set, struct pt_regs * regs) { struct rt_sigframe *frame; int err = 0; frame = get_sigframe(ka, regs, sizeof(*frame)); if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) goto give_sigsegv; err |= __put_user((current->exec_domain && current->exec_domain->signal_invmap && sig < 32 ? current->exec_domain->signal_invmap[sig] : sig), &frame->sig); err |= __put_user(&frame->info, &frame->pinfo); err |= __put_user(&frame->uc, &frame->puc); err |= copy_siginfo_to_user(&frame->info, info); if (err) goto give_sigsegv; /* Create the ucontext. */ err |= __put_user(0, &frame->uc.uc_flags); err |= __put_user(0, &frame->uc.uc_link); err |= __put_user(current->sas_ss_sp, &frame->uc.uc_stack.ss_sp); err |= __put_user(sas_ss_flags(regs->esp), &frame->uc.uc_stack.ss_flags); err |= __put_user(current->sas_ss_size, &frame->uc.uc_stack.ss_size); err |= setup_sigcontext(&frame->uc.uc_mcontext, &frame->fpstate, regs, set->sig[0]); err |= __copy_to_user(&frame->uc.uc_sigmask, set, sizeof(*set)); if (err) goto give_sigsegv; /* Set up to return from userspace. If provided, use a stub already in userspace. */ if (ka->sa.sa_flags & SA_RESTORER) { err |= __put_user(ka->sa.sa_restorer, &frame->pretcode); } else { err |= __put_user(frame->retcode, &frame->pretcode); /* This is movl $,%eax ; int $0x80 */ err |= __put_user(0xb8, (char *)(frame->retcode+0)); err |= __put_user(__NR_rt_sigreturn, (int *)(frame->retcode+1)); err |= __put_user(0x80cd, (short *)(frame->retcode+5)); } if (err) goto give_sigsegv; /* Set up registers for signal handler */ regs->esp = (unsigned long) frame; regs->eip = (unsigned long) ka->sa.sa_handler; set_fs(USER_DS); regs->xds = __USER_DS; regs->xes = __USER_DS; regs->xss = __USER_DS; regs->xcs = __USER_CS; regs->eflags &= ~TF_MASK; #if DEBUG_SIG printk("SIG deliver (%s:%d): sp=%p pc=%p ra=%p\n", current->comm, current->pid, frame, regs->eip, frame->pretcode); #endif return; give_sigsegv: if (sig == SIGSEGV) ka->sa.sa_handler = SIG_DFL; force_sig(SIGSEGV, current); } /* * OK, we're invoking a handler */ static void handle_signal(unsigned long sig, struct k_sigaction *ka, siginfo_t *info, sigset_t *oldset, struct pt_regs * regs) { /* Are we from a system call? */ if (regs->orig_eax >= 0) { /* If so, check system call restarting.. */ switch (regs->eax) { case -ERESTARTNOHAND: regs->eax = -EINTR; break; case -ERESTARTSYS: if (!(ka->sa.sa_flags & SA_RESTART)) { regs->eax = -EINTR; break; } /* fallthrough */ case -ERESTARTNOINTR: regs->eax = regs->orig_eax; regs->eip -= 2; } } /* Set up the stack frame */ if (ka->sa.sa_flags & SA_SIGINFO) setup_rt_frame(sig, ka, info, oldset, regs); else setup_frame(sig, ka, oldset, regs); if (ka->sa.sa_flags & SA_ONESHOT) ka->sa.sa_handler = SIG_DFL; if (!(ka->sa.sa_flags & SA_NODEFER)) { spin_lock_irq(¤t->sigmask_lock); sigorsets(¤t->blocked,¤t->blocked,&ka->sa.sa_mask); sigaddset(¤t->blocked,sig); recalc_sigpending(current); spin_unlock_irq(¤t->sigmask_lock); } } /* * Note that 'init' is a special process: it doesn't get signals it doesn't * want to handle. Thus you cannot kill init even with a SIGKILL even by * mistake. */ int do_signal(struct pt_regs *regs, sigset_t *oldset) { siginfo_t info; struct k_sigaction *ka; /* * We want the common case to go fast, which * is why we may in certain cases get here from * kernel mode. Just return without doing anything * if so. */ if ((regs->xcs & 3) != 3) return 1; if (!oldset) oldset = ¤t->blocked; for (;;) { unsigned long signr; spin_lock_irq(¤t->sigmask_lock); signr = dequeue_signal(¤t->blocked, &info); spin_unlock_irq(¤t->sigmask_lock); if (!signr) break; if ((current->ptrace&PT_PTRACED) && signr != SIGKILL) { /* Let the debugger run. */ current->exit_code = signr; current->state = TASK_STOPPED; notify_parent(current, SIGCHLD); schedule(); /* We're back. Did the debugger cancel the sig? */ if (!(signr = current->exit_code)) continue; current->exit_code = 0; /* The debugger continued. Ignore SIGSTOP. */ if (signr == SIGSTOP) continue; /* Update the siginfo structure. Is this good? */ if (signr != info.si_signo) { info.si_signo = signr; info.si_errno = 0; info.si_code = SI_USER; info.si_pid = current->p_pptr->pid; info.si_uid = current->p_pptr->uid; } /* If the (new) signal is now blocked, requeue it. */ if (sigismember(¤t->blocked, signr)) { send_sig_info(signr, &info, current); continue; } } ka = ¤t->sig->action[signr-1]; if (ka->sa.sa_handler == SIG_IGN) { if (signr != SIGCHLD) continue; /* Check for SIGCHLD: it's special. */ while (sys_wait4(-1, NULL, WNOHANG, NULL) > 0) /* nothing */; continue; } if (ka->sa.sa_handler == SIG_DFL) { int exit_code = signr; /* Init gets no signals it doesn't want. */ if (current->pid == 1) continue; switch (signr) { case SIGCONT: case SIGCHLD: case SIGWINCH: continue; case SIGTSTP: case SIGTTIN: case SIGTTOU: if (is_orphaned_pgrp(current->pgrp)) continue; /* FALLTHRU */ case SIGSTOP: current->state = TASK_STOPPED; current->exit_code = signr; if (!(current->p_pptr->sig->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDSTOP)) notify_parent(current, SIGCHLD); schedule(); continue; case SIGQUIT: case SIGILL: case SIGTRAP: case SIGABRT: case SIGFPE: case SIGSEGV: case SIGBUS: case SIGSYS: case SIGXCPU: case SIGXFSZ: if (do_coredump(signr, regs)) exit_code |= 0x80; /* FALLTHRU */ default: lock_kernel(); sigaddset(¤t->signal, signr); recalc_sigpending(current); current->flags |= PF_SIGNALED; do_exit(exit_code); /* NOTREACHED */ } } /* Whee! Actually deliver the signal. */ handle_signal(signr, ka, &info, oldset, regs); return 1; } /* Did we come from a system call? */ if (regs->orig_eax >= 0) { /* Restart the system call - no handlers present */ if (regs->eax == -ERESTARTNOHAND || regs->eax == -ERESTARTSYS || regs->eax == -ERESTARTNOINTR) { regs->eax = regs->orig_eax; regs->eip -= 2; } } return 0; }