signal.c

qemu虚拟机代码

	struct rt_sigframe *frame = (struct rt_sigframe *)g2h(env->regs[R_ESP] - 4);
        sigset_t set;
        //	stack_t st;
	int eax;

#if 0
	if (verify_area(VERIFY_READ, frame, sizeof(*frame)))
		goto badframe;
#endif
        target_to_host_sigset(&set, &frame->uc.tuc_sigmask);
        sigprocmask(SIG_SETMASK, &set, NULL);
	
	if (restore_sigcontext(env, &frame->uc.tuc_mcontext, &eax))
		goto badframe;

#if 0
	if (__copy_from_user(&st, &frame->uc.tuc_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);
#endif
	return eax;

badframe:
	force_sig(TARGET_SIGSEGV);
	return 0;
}

#elif defined(TARGET_ARM)

struct target_sigcontext {
	target_ulong trap_no;
	target_ulong error_code;
	target_ulong oldmask;
	target_ulong arm_r0;
	target_ulong arm_r1;
	target_ulong arm_r2;
	target_ulong arm_r3;
	target_ulong arm_r4;
	target_ulong arm_r5;
	target_ulong arm_r6;
	target_ulong arm_r7;
	target_ulong arm_r8;
	target_ulong arm_r9;
	target_ulong arm_r10;
	target_ulong arm_fp;
	target_ulong arm_ip;
	target_ulong arm_sp;
	target_ulong arm_lr;
	target_ulong arm_pc;
	target_ulong arm_cpsr;
	target_ulong fault_address;
};

typedef struct target_sigaltstack {
	target_ulong ss_sp;
	int ss_flags;
	target_ulong ss_size;
} target_stack_t;

struct target_ucontext {
    target_ulong tuc_flags;
    target_ulong tuc_link;
    target_stack_t tuc_stack;
    struct target_sigcontext tuc_mcontext;
    target_sigset_t  tuc_sigmask;	/* mask last for extensibility */
};

struct sigframe
{
    struct target_sigcontext sc;
    target_ulong extramask[TARGET_NSIG_WORDS-1];
    target_ulong retcode;
};

struct rt_sigframe
{
    struct target_siginfo *pinfo;
    void *puc;
    struct target_siginfo info;
    struct target_ucontext uc;
    target_ulong retcode;
};

#define TARGET_CONFIG_CPU_32 1

/*
 * For ARM syscalls, we encode the syscall number into the instruction.
 */
#define SWI_SYS_SIGRETURN	(0xef000000|(TARGET_NR_sigreturn + ARM_SYSCALL_BASE))
#define SWI_SYS_RT_SIGRETURN	(0xef000000|(TARGET_NR_rt_sigreturn + ARM_SYSCALL_BASE))

/*
 * For Thumb syscalls, we pass the syscall number via r7.  We therefore
 * need two 16-bit instructions.
 */
#define SWI_THUMB_SIGRETURN	(0xdf00 << 16 | 0x2700 | (TARGET_NR_sigreturn))
#define SWI_THUMB_RT_SIGRETURN	(0xdf00 << 16 | 0x2700 | (TARGET_NR_rt_sigreturn))

static const target_ulong retcodes[4] = {
	SWI_SYS_SIGRETURN,	SWI_THUMB_SIGRETURN,
	SWI_SYS_RT_SIGRETURN,	SWI_THUMB_RT_SIGRETURN
};


#define __put_user_error(x,p,e) __put_user(x, p)
#define __get_user_error(x,p,e) __get_user(x, p)

static inline int valid_user_regs(CPUState *regs)
{
    return 1;
}

static int
setup_sigcontext(struct target_sigcontext *sc, /*struct _fpstate *fpstate,*/
		 CPUState *env, unsigned long mask)
{
	int err = 0;

	__put_user_error(env->regs[0], &sc->arm_r0, err);
	__put_user_error(env->regs[1], &sc->arm_r1, err);
	__put_user_error(env->regs[2], &sc->arm_r2, err);
	__put_user_error(env->regs[3], &sc->arm_r3, err);
	__put_user_error(env->regs[4], &sc->arm_r4, err);
	__put_user_error(env->regs[5], &sc->arm_r5, err);
	__put_user_error(env->regs[6], &sc->arm_r6, err);
	__put_user_error(env->regs[7], &sc->arm_r7, err);
	__put_user_error(env->regs[8], &sc->arm_r8, err);
	__put_user_error(env->regs[9], &sc->arm_r9, err);
	__put_user_error(env->regs[10], &sc->arm_r10, err);
	__put_user_error(env->regs[11], &sc->arm_fp, err);
	__put_user_error(env->regs[12], &sc->arm_ip, err);
	__put_user_error(env->regs[13], &sc->arm_sp, err);
	__put_user_error(env->regs[14], &sc->arm_lr, err);
	__put_user_error(env->regs[15], &sc->arm_pc, err);
#ifdef TARGET_CONFIG_CPU_32
	__put_user_error(cpsr_read(env), &sc->arm_cpsr, err);
#endif

	__put_user_error(/* current->thread.trap_no */ 0, &sc->trap_no, err);
	__put_user_error(/* current->thread.error_code */ 0, &sc->error_code, err);
	__put_user_error(/* current->thread.address */ 0, &sc->fault_address, err);
	__put_user_error(mask, &sc->oldmask, err);

	return err;
}

static inline void *
get_sigframe(struct emulated_sigaction *ka, CPUState *regs, int framesize)
{
	unsigned long sp = regs->regs[13];

#if 0
	/*
	 * This is the X/Open sanctioned signal stack switching.
	 */
	if ((ka->sa.sa_flags & SA_ONSTACK) && !sas_ss_flags(sp))
		sp = current->sas_ss_sp + current->sas_ss_size;
#endif
	/*
	 * ATPCS B01 mandates 8-byte alignment
	 */
	return g2h((sp - framesize) & ~7);
}

static int
setup_return(CPUState *env, struct emulated_sigaction *ka,
	     target_ulong *rc, void *frame, int usig)
{
	target_ulong handler = (target_ulong)ka->sa._sa_handler;
	target_ulong retcode;
	int thumb = 0;
#if defined(TARGET_CONFIG_CPU_32)
#if 0
	target_ulong cpsr = env->cpsr;

	/*
	 * Maybe we need to deliver a 32-bit signal to a 26-bit task.
	 */
	if (ka->sa.sa_flags & SA_THIRTYTWO)
		cpsr = (cpsr & ~MODE_MASK) | USR_MODE;

#ifdef CONFIG_ARM_THUMB
	if (elf_hwcap & HWCAP_THUMB) {
		/*
		 * The LSB of the handler determines if we're going to
		 * be using THUMB or ARM mode for this signal handler.
		 */
		thumb = handler & 1;

		if (thumb)
			cpsr |= T_BIT;
		else
			cpsr &= ~T_BIT;
	}
#endif
#endif
#endif /* TARGET_CONFIG_CPU_32 */

	if (ka->sa.sa_flags & TARGET_SA_RESTORER) {
		retcode = (target_ulong)ka->sa.sa_restorer;
	} else {
		unsigned int idx = thumb;

		if (ka->sa.sa_flags & TARGET_SA_SIGINFO)
			idx += 2;

		if (__put_user(retcodes[idx], rc))
			return 1;
#if 0
		flush_icache_range((target_ulong)rc,
				   (target_ulong)(rc + 1));
#endif
		retcode = ((target_ulong)rc) + thumb;
	}

	env->regs[0] = usig;
	env->regs[13] = h2g(frame);
	env->regs[14] = retcode;
	env->regs[15] = handler & (thumb ? ~1 : ~3);

#if 0
#ifdef TARGET_CONFIG_CPU_32
	env->cpsr = cpsr;
#endif
#endif

	return 0;
}

static void setup_frame(int usig, struct emulated_sigaction *ka,
			target_sigset_t *set, CPUState *regs)
{
	struct sigframe *frame = get_sigframe(ka, regs, sizeof(*frame));
	int i, err = 0;

	err |= setup_sigcontext(&frame->sc, /*&frame->fpstate,*/ regs, set->sig[0]);

        for(i = 1; i < TARGET_NSIG_WORDS; i++) {
            if (__put_user(set->sig[i], &frame->extramask[i - 1]))
                return;
	}

	if (err == 0)
            err = setup_return(regs, ka, &frame->retcode, frame, usig);
        //	return err;
}

static void setup_rt_frame(int usig, struct emulated_sigaction *ka, 
                           target_siginfo_t *info,
			   target_sigset_t *set, CPUState *env)
{
	struct rt_sigframe *frame = get_sigframe(ka, env, sizeof(*frame));
	int i, err = 0;

	if (!access_ok(VERIFY_WRITE, frame, sizeof (*frame)))
            return /* 1 */;

	__put_user_error(&frame->info, (target_ulong *)&frame->pinfo, err);
	__put_user_error(&frame->uc, (target_ulong *)&frame->puc, err);
	err |= copy_siginfo_to_user(&frame->info, info);

	/* Clear all the bits of the ucontext we don't use.  */
	memset(&frame->uc, 0, offsetof(struct target_ucontext, tuc_mcontext));

	err |= setup_sigcontext(&frame->uc.tuc_mcontext, /*&frame->fpstate,*/
				env, set->sig[0]);
        for(i = 0; i < TARGET_NSIG_WORDS; i++) {
            if (__put_user(set->sig[i], &frame->uc.tuc_sigmask.sig[i]))
                return;
        }

	if (err == 0)
		err = setup_return(env, ka, &frame->retcode, frame, usig);

	if (err == 0) {
		/*
		 * For realtime signals we must also set the second and third
		 * arguments for the signal handler.
		 *   -- Peter Maydell <[e-mail]> 2000-12-06
		 */
            env->regs[1] = (target_ulong)frame->pinfo;
            env->regs[2] = (target_ulong)frame->puc;
	}

        //	return err;
}

static int
restore_sigcontext(CPUState *env, struct target_sigcontext *sc)
{
	int err = 0;
        uint32_t cpsr;

	__get_user_error(env->regs[0], &sc->arm_r0, err);
	__get_user_error(env->regs[1], &sc->arm_r1, err);
	__get_user_error(env->regs[2], &sc->arm_r2, err);
	__get_user_error(env->regs[3], &sc->arm_r3, err);
	__get_user_error(env->regs[4], &sc->arm_r4, err);
	__get_user_error(env->regs[5], &sc->arm_r5, err);
	__get_user_error(env->regs[6], &sc->arm_r6, err);
	__get_user_error(env->regs[7], &sc->arm_r7, err);
	__get_user_error(env->regs[8], &sc->arm_r8, err);
	__get_user_error(env->regs[9], &sc->arm_r9, err);
	__get_user_error(env->regs[10], &sc->arm_r10, err);
	__get_user_error(env->regs[11], &sc->arm_fp, err);
	__get_user_error(env->regs[12], &sc->arm_ip, err);
	__get_user_error(env->regs[13], &sc->arm_sp, err);
	__get_user_error(env->regs[14], &sc->arm_lr, err);
	__get_user_error(env->regs[15], &sc->arm_pc, err);
#ifdef TARGET_CONFIG_CPU_32
	__get_user_error(cpsr, &sc->arm_cpsr, err);
        cpsr_write(env, cpsr, 0xffffffff);
#endif

	err |= !valid_user_regs(env);

	return err;
}

long do_sigreturn(CPUState *env)
{
	struct sigframe *frame;
	target_sigset_t set;
        sigset_t host_set;
        int i;

	/*
	 * Since we stacked the signal on a 64-bit boundary,
	 * then 'sp' should be word aligned here.  If it's
	 * not, then the user is trying to mess with us.
	 */
	if (env->regs[13] & 7)
		goto badframe;

	frame = (struct sigframe *)g2h(env->regs[13]);

#if 0
	if (verify_area(VERIFY_READ, frame, sizeof (*frame)))
		goto badframe;
#endif
	if (__get_user(set.sig[0], &frame->sc.oldmask))
            goto badframe;
        for(i = 1; i < TARGET_NSIG_WORDS; i++) {
            if (__get_user(set.sig[i], &frame->extramask[i - 1]))
                goto badframe;
        }

        target_to_host_sigset_internal(&host_set, &set);
        sigprocmask(SIG_SETMASK, &host_set, NULL);

	if (restore_sigcontext(env, &frame->sc))
		goto badframe;

#if 0
	/* Send SIGTRAP if we're single-stepping */
	if (ptrace_cancel_bpt(current))
		send_sig(SIGTRAP, current, 1);
#endif
	return env->regs[0];

badframe:
        force_sig(SIGSEGV /* , current */);
	return 0;
}

long do_rt_sigreturn(CPUState *env)
{
	struct rt_sigframe *frame;
        sigset_t host_set;

	/*
	 * Since we stacked the signal on a 64-bit boundary,
	 * then 'sp' should be word aligned here.  If it's
	 * not, then the user is trying to mess with us.
	 */
	if (env->regs[13] & 7)
		goto badframe;

	frame = (struct rt_sigframe *)env->regs[13];

#if 0
	if (verify_area(VERIFY_READ, frame, sizeof (*frame)))
		goto badframe;
#endif
        target_to_host_sigset(&host_set, &frame->uc.tuc_sigmask);
        sigprocmask(SIG_SETMASK, &host_set, NULL);

	if (restore_sigcontext(env, &frame->uc.tuc_mcontext))
		goto badframe;

#if 0
	/* Send SIGTRAP if we're single-stepping */
	if (ptrace_cancel_bpt(current))
		send_sig(SIGTRAP, current, 1);
#endif
	return env->regs[0];

badframe:
        force_sig(SIGSEGV /* , current */);
	return 0;
}

#elif defined(TARGET_SPARC)

#define __SUNOS_MAXWIN   31

/* This is what SunOS does, so shall I. */
struct target_sigcontext {
        target_ulong sigc_onstack;      /* state to restore */

        target_ulong sigc_mask;         /* sigmask to restore */
        target_ulong sigc_sp;           /* stack pointer */
        target_ulong sigc_pc;           /* program counter */
        target_ulong sigc_npc;          /* next program counter */
        target_ulong sigc_psr;          /* for condition codes etc */
        target_ulong sigc_g1;           /* User uses these two registers */
        target_ulong sigc_o0;           /* within the trampoline code. */

        /* Now comes information regarding the users window set
         * at the time of the signal.
         */
        target_ulong sigc_oswins;       /* outstanding windows */

        /* stack ptrs for each regwin buf */
        char *sigc_spbuf[__SUNOS_MAXWIN];

        /* Windows to restore after signal */
        struct {
                target_ulong locals[8];
                target_ulong ins[8];
        } sigc_wbuf[__SUNOS_MAXWIN];
};