ia32_signal.c

linux 内核源代码

/*
 *  linux/arch/x86_64/ia32/ia32_signal.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *
 *  1997-11-28  Modified for POSIX.1b signals by Richard Henderson
 *  2000-06-20  Pentium III FXSR, SSE support by Gareth Hughes
 *  2000-12-*   x86-64 compatibility mode signal handling by Andi Kleen
 */

#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/kernel.h>
#include <linux/signal.h>
#include <linux/errno.h>
#include <linux/wait.h>
#include <linux/ptrace.h>
#include <linux/unistd.h>
#include <linux/stddef.h>
#include <linux/personality.h>
#include <linux/compat.h>
#include <linux/binfmts.h>
#include <asm/ucontext.h>
#include <asm/uaccess.h>
#include <asm/i387.h>
#include <asm/ia32.h>
#include <asm/ptrace.h>
#include <asm/ia32_unistd.h>
#include <asm/user32.h>
#include <asm/sigcontext32.h>
#include <asm/fpu32.h>
#include <asm/proto.h>
#include <asm/vsyscall32.h>

#define DEBUG_SIG 0

#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))

asmlinkage int do_signal(struct pt_regs *regs, sigset_t *oldset);
void signal_fault(struct pt_regs *regs, void __user *frame, char *where);

int copy_siginfo_to_user32(compat_siginfo_t __user *to, siginfo_t *from)
{
	int err;
	if (!access_ok (VERIFY_WRITE, to, sizeof(compat_siginfo_t)))
		return -EFAULT;

	/* If you change siginfo_t structure, please make sure that
	   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);

	if (from->si_code < 0) {
		err |= __put_user(from->si_pid, &to->si_pid);
 		err |= __put_user(from->si_uid, &to->si_uid);
 		err |= __put_user(ptr_to_compat(from->si_ptr), &to->si_ptr);
	} else {
 		/* First 32bits of unions are always present:
 		 * si_pid === si_band === si_tid === si_addr(LS half) */
		err |= __put_user(from->_sifields._pad[0], &to->_sifields._pad[0]);
		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);
			/* FALL THROUGH */
		default:
		case __SI_KILL >> 16:
			err |= __put_user(from->si_uid, &to->si_uid);
			break;
		case __SI_POLL >> 16:
			err |= __put_user(from->si_fd, &to->si_fd); 
			break;
		case __SI_TIMER >> 16:
			err |= __put_user(from->si_overrun, &to->si_overrun); 
			err |= __put_user(ptr_to_compat(from->si_ptr),
					&to->si_ptr);
			break;
		case __SI_RT >> 16: /* This is not generated by the kernel as of now.  */
		case __SI_MESGQ >> 16:
			err |= __put_user(from->si_uid, &to->si_uid);
			err |= __put_user(from->si_int, &to->si_int);
			break;
		}
	}
	return err;
}

int copy_siginfo_from_user32(siginfo_t *to, compat_siginfo_t __user *from)
{
	int err;
	u32 ptr32;
	if (!access_ok (VERIFY_READ, from, sizeof(compat_siginfo_t)))
		return -EFAULT;

	err = __get_user(to->si_signo, &from->si_signo);
	err |= __get_user(to->si_errno, &from->si_errno);
	err |= __get_user(to->si_code, &from->si_code);

	err |= __get_user(to->si_pid, &from->si_pid);
	err |= __get_user(to->si_uid, &from->si_uid);
	err |= __get_user(ptr32, &from->si_ptr);
	to->si_ptr = compat_ptr(ptr32);

	return err;
}

asmlinkage long
sys32_sigsuspend(int history0, int history1, old_sigset_t mask)
{
	mask &= _BLOCKABLE;
	spin_lock_irq(&current->sighand->siglock);
	current->saved_sigmask = current->blocked;
	siginitset(&current->blocked, mask);
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);

	current->state = TASK_INTERRUPTIBLE;
	schedule();
	set_thread_flag(TIF_RESTORE_SIGMASK);
	return -ERESTARTNOHAND;
}

asmlinkage long
sys32_sigaltstack(const stack_ia32_t __user *uss_ptr,
		  stack_ia32_t __user *uoss_ptr, 
		  struct pt_regs *regs)
{
	stack_t uss,uoss; 
	int ret;
	mm_segment_t seg; 
	if (uss_ptr) { 
		u32 ptr;
		memset(&uss,0,sizeof(stack_t));
		if (!access_ok(VERIFY_READ,uss_ptr,sizeof(stack_ia32_t)) ||
			    __get_user(ptr, &uss_ptr->ss_sp) ||
			    __get_user(uss.ss_flags, &uss_ptr->ss_flags) ||
			    __get_user(uss.ss_size, &uss_ptr->ss_size))
			return -EFAULT;
		uss.ss_sp = compat_ptr(ptr);
	}
	seg = get_fs(); 
	set_fs(KERNEL_DS); 
	ret = do_sigaltstack(uss_ptr ? &uss : NULL, &uoss, regs->rsp);
	set_fs(seg); 
	if (ret >= 0 && uoss_ptr)  {
		if (!access_ok(VERIFY_WRITE,uoss_ptr,sizeof(stack_ia32_t)) ||
		    __put_user(ptr_to_compat(uoss.ss_sp), &uoss_ptr->ss_sp) ||
		    __put_user(uoss.ss_flags, &uoss_ptr->ss_flags) ||
		    __put_user(uoss.ss_size, &uoss_ptr->ss_size))
			ret = -EFAULT;
	} 	
	return ret;	
}

/*
 * Do a signal return; undo the signal stack.
 */

struct sigframe
{
	u32 pretcode;
	int sig;
	struct sigcontext_ia32 sc;
	struct _fpstate_ia32 fpstate;
	unsigned int extramask[_COMPAT_NSIG_WORDS-1];
	char retcode[8];
};

struct rt_sigframe
{
	u32 pretcode;
	int sig;
	u32 pinfo;
	u32 puc;
	compat_siginfo_t info;
	struct ucontext_ia32 uc;
	struct _fpstate_ia32 fpstate;
	char retcode[8];
};

static int
ia32_restore_sigcontext(struct pt_regs *regs, struct sigcontext_ia32 __user *sc, unsigned int *peax)
{
	unsigned int err = 0;
	
	/* Always make any pending restarted system calls return -EINTR */
	current_thread_info()->restart_block.fn = do_no_restart_syscall;

#if DEBUG_SIG
	printk("SIG restore_sigcontext: sc=%p err(%x) eip(%x) cs(%x) flg(%x)\n",
		sc, sc->err, sc->eip, sc->cs, sc->eflags);
#endif
#define COPY(x)		{ \
	unsigned int reg;			\
	err |= __get_user(reg, &sc->e ##x);	\
	regs->r ## x = reg;			\
}

#define RELOAD_SEG(seg,mask)						\
	{ unsigned int cur; 						\
	  unsigned short pre;						\
	  err |= __get_user(pre, &sc->seg);				\
    	  asm volatile("movl %%" #seg ",%0" : "=r" (cur));		\
	  pre |= mask; 							\
	  if (pre != cur) loadsegment(seg,pre); }

	/* Reload fs and gs if they have changed in the signal handler.
	   This does not handle long fs/gs base changes in the handler, but 
	   does not clobber them at least in the normal case. */ 
	
	{
		unsigned gs, oldgs; 
		err |= __get_user(gs, &sc->gs);
		gs |= 3; 
		asm("movl %%gs,%0" : "=r" (oldgs));
		if (gs != oldgs)
		load_gs_index(gs); 
	} 
	RELOAD_SEG(fs,3);
	RELOAD_SEG(ds,3);
	RELOAD_SEG(es,3);

	COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);
	COPY(dx); COPY(cx); COPY(ip);
	/* Don't touch extended registers */ 
	
	err |= __get_user(regs->cs, &sc->cs); 
	regs->cs |= 3;  
	err |= __get_user(regs->ss, &sc->ss); 
	regs->ss |= 3; 

	{
		unsigned int tmpflags;
		err |= __get_user(tmpflags, &sc->eflags);
		regs->eflags = (regs->eflags & ~0x40DD5) | (tmpflags & 0x40DD5);
		regs->orig_rax = -1;		/* disable syscall checks */
	}

	{
		u32 tmp;
		struct _fpstate_ia32 __user * buf;
		err |= __get_user(tmp, &sc->fpstate);
		buf = compat_ptr(tmp);
		if (buf) {
			if (!access_ok(VERIFY_READ, buf, sizeof(*buf)))
				goto badframe;
			err |= restore_i387_ia32(current, buf, 0);
		} else {
			struct task_struct *me = current;
			if (used_math()) {
				clear_fpu(me);
				clear_used_math();
			}
		}
	}

	{ 
		u32 tmp;
		err |= __get_user(tmp, &sc->eax);
		*peax = tmp;
	}
	return err;

badframe:
	return 1;
}

asmlinkage long sys32_sigreturn(struct pt_regs *regs)
{
	struct sigframe __user *frame = (struct sigframe __user *)(regs->rsp-8);
	sigset_t set;
	unsigned int eax;

	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
		goto badframe;
	if (__get_user(set.sig[0], &frame->sc.oldmask)
	    || (_COMPAT_NSIG_WORDS > 1
		&& __copy_from_user((((char *) &set.sig) + 4), &frame->extramask,
				    sizeof(frame->extramask))))
		goto badframe;

	sigdelsetmask(&set, ~_BLOCKABLE);
	spin_lock_irq(&current->sighand->siglock);
	current->blocked = set;
	recalc_sigpending();
	spin_unlock_irq(&current->sighand->siglock);
	
	if (ia32_restore_sigcontext(regs, &frame->sc, &eax))
		goto badframe;
	return eax;

badframe:
	signal_fault(regs, frame, "32bit sigreturn");
	return 0;
}	

asmlinkage long sys32_rt_sigreturn(struct pt_regs *regs)
{
	struct rt_sigframe __user *frame;
	sigset_t set;
	unsigned int eax;