Beispiel #1
0
/*
 * Function:	unix_syscall
 *
 * Inputs:	regs	- pointer to i386 save area
 *
 * Outputs:	none
 */
void
unix_syscall(x86_saved_state_t *state)
{
	thread_t		thread;
	void			*vt;
	unsigned int		code;
	struct sysent		*callp;

	int			error;
	vm_offset_t		params;
	struct proc		*p;
	struct uthread		*uthread;
	x86_saved_state32_t	*regs;
	boolean_t		is_vfork;

	assert(is_saved_state32(state));
	regs = saved_state32(state);
#if DEBUG
	if (regs->eax == 0x800)
		thread_exception_return();
#endif
	thread = current_thread();
	uthread = get_bsdthread_info(thread);

	/* Get the approriate proc; may be different from task's for vfork() */
	is_vfork = uthread->uu_flag & UT_VFORK;
	if (__improbable(is_vfork != 0))
		p = current_proc();
	else 
		p = (struct proc *)get_bsdtask_info(current_task());

	/* Verify that we are not being called from a task without a proc */
	if (__improbable(p == NULL)) {
		regs->eax = EPERM;
		regs->efl |= EFL_CF;
		task_terminate_internal(current_task());
		thread_exception_return();
		/* NOTREACHED */
	}

	code = regs->eax & I386_SYSCALL_NUMBER_MASK;
	DEBUG_KPRINT_SYSCALL_UNIX("unix_syscall: code=%d(%s) eip=%u\n",
							  code, syscallnames[code >= NUM_SYSENT ? 63 : code], (uint32_t)regs->eip);
	params = (vm_offset_t) (regs->uesp + sizeof (int));

	regs->efl &= ~(EFL_CF);

	callp = (code >= NUM_SYSENT) ? &sysent[63] : &sysent[code];

	if (__improbable(callp == sysent)) {
		code = fuword(params);
		params += sizeof(int);
		callp = (code >= NUM_SYSENT) ? &sysent[63] : &sysent[code];
	}

	vt = (void *)uthread->uu_arg;

	if (callp->sy_arg_bytes != 0) {
#if CONFIG_REQUIRES_U32_MUNGING
		sy_munge_t	*mungerp;
#else
#error U32 syscalls on x86_64 kernel requires munging
#endif
		uint32_t	 nargs;

		assert((unsigned) callp->sy_arg_bytes <= sizeof (uthread->uu_arg));
		nargs = callp->sy_arg_bytes;
		error = copyin((user_addr_t) params, (char *) vt, nargs);
		if (error) {
			regs->eax = error;
			regs->efl |= EFL_CF;
			thread_exception_return();
			/* NOTREACHED */
		}

		if (__probable(code != 180)) {
	        	int *ip = (int *)vt;

			KERNEL_DEBUG_CONSTANT_IST(KDEBUG_TRACE,
				BSDDBG_CODE(DBG_BSD_EXCP_SC, code) | DBG_FUNC_START,
				*ip, *(ip+1), *(ip+2), *(ip+3), 0);
		}

#if CONFIG_REQUIRES_U32_MUNGING
		mungerp = callp->sy_arg_munge32;

		if (mungerp != NULL)
			(*mungerp)(vt);
#endif
	} else
		KERNEL_DEBUG_CONSTANT_IST(KDEBUG_TRACE, 
			BSDDBG_CODE(DBG_BSD_EXCP_SC, code) | DBG_FUNC_START,
			0, 0, 0, 0, 0);

	/*
	 * Delayed binding of thread credential to process credential, if we
	 * are not running with an explicitly set thread credential.
	 */
	kauth_cred_uthread_update(uthread, p);

	uthread->uu_rval[0] = 0;
	uthread->uu_rval[1] = 0;
	uthread->uu_flag |= UT_NOTCANCELPT;
	uthread->syscall_code = code;

#ifdef JOE_DEBUG
        uthread->uu_iocount = 0;
        uthread->uu_vpindex = 0;
#endif

	AUDIT_SYSCALL_ENTER(code, p, uthread);
	error = (*(callp->sy_call))((void *) p, (void *) vt, &(uthread->uu_rval[0]));
	AUDIT_SYSCALL_EXIT(code, p, uthread, error);

#ifdef JOE_DEBUG
        if (uthread->uu_iocount)
                printf("system call returned with uu_iocount != 0\n");
#endif
#if CONFIG_DTRACE
	uthread->t_dtrace_errno = error;
#endif /* CONFIG_DTRACE */

	if (__improbable(error == ERESTART)) {
		/*
		 * Move the user's pc back to repeat the syscall:
		 * 5 bytes for a sysenter, or 2 for an int 8x.
		 * The SYSENTER_TF_CS covers single-stepping over a sysenter
		 * - see debug trap handler in idt.s/idt64.s
		 */

		pal_syscall_restart(thread, state);
	}
	else if (error != EJUSTRETURN) {
		if (__improbable(error)) {
		    regs->eax = error;
		    regs->efl |= EFL_CF;	/* carry bit */
		} else { /* (not error) */
			/*
			 * We split retval across two registers, in case the
			 * syscall had a 64-bit return value, in which case
			 * eax/edx matches the function call ABI.
			 */
		    regs->eax = uthread->uu_rval[0];
		    regs->edx = uthread->uu_rval[1];
		} 
	}

	DEBUG_KPRINT_SYSCALL_UNIX(
		"unix_syscall: error=%d retval=(%u,%u)\n",
		error, regs->eax, regs->edx);

	uthread->uu_flag &= ~UT_NOTCANCELPT;

	if (__improbable(uthread->uu_lowpri_window)) {
	        /*
		 * task is marked as a low priority I/O type
		 * and the I/O we issued while in this system call
		 * collided with normal I/O operations... we'll
		 * delay in order to mitigate the impact of this
		 * task on the normal operation of the system
		 */
		throttle_lowpri_io(1);
	}
	if (__probable(code != 180))
		KERNEL_DEBUG_CONSTANT_IST(KDEBUG_TRACE, 
			BSDDBG_CODE(DBG_BSD_EXCP_SC, code) | DBG_FUNC_END,
			error, uthread->uu_rval[0], uthread->uu_rval[1], p->p_pid, 0);

	if (__improbable(!is_vfork && callp->sy_call == (sy_call_t *)execve && !error)) {
		pal_execve_return(thread);
	}

	thread_exception_return();
	/* NOTREACHED */
}
Beispiel #2
0
static inline int
syscallenter(struct thread *td, struct syscall_args *sa)
{
	struct proc *p;
	int error, traced;

	PCPU_INC(cnt.v_syscall);
	p = td->td_proc;

	td->td_pticks = 0;
	if (td->td_ucred != p->p_ucred)
		cred_update_thread(td);
	if (p->p_flag & P_TRACED) {
		traced = 1;
		PROC_LOCK(p);
		td->td_dbgflags &= ~TDB_USERWR;
		td->td_dbgflags |= TDB_SCE;
		PROC_UNLOCK(p);
	} else
		traced = 0;
	error = (p->p_sysent->sv_fetch_syscall_args)(td, sa);
#ifdef KTRACE
	if (KTRPOINT(td, KTR_SYSCALL))
		ktrsyscall(sa->code, sa->narg, sa->args);
#endif

	CTR6(KTR_SYSC,
"syscall: td=%p pid %d %s (%#lx, %#lx, %#lx)",
	    td, td->td_proc->p_pid, syscallname(p, sa->code),
	    sa->args[0], sa->args[1], sa->args[2]);

	if (error == 0) {
		STOPEVENT(p, S_SCE, sa->narg);
		if (p->p_flag & P_TRACED && p->p_stops & S_PT_SCE) {
			PROC_LOCK(p);
			ptracestop((td), SIGTRAP);
			PROC_UNLOCK(p);
		}
		if (td->td_dbgflags & TDB_USERWR) {
			/*
			 * Reread syscall number and arguments if
			 * debugger modified registers or memory.
			 */
			error = (p->p_sysent->sv_fetch_syscall_args)(td, sa);
#ifdef KTRACE
			if (KTRPOINT(td, KTR_SYSCALL))
				ktrsyscall(sa->code, sa->narg, sa->args);
#endif
			if (error != 0)
				goto retval;
		}

#ifdef CAPABILITY_MODE
		/*
		 * In capability mode, we only allow access to system calls
		 * flagged with SYF_CAPENABLED.
		 */
		if (IN_CAPABILITY_MODE(td) &&
		    !(sa->callp->sy_flags & SYF_CAPENABLED)) {
			error = ECAPMODE;
			goto retval;
		}
#endif

		error = syscall_thread_enter(td, sa->callp);
		if (error != 0)
			goto retval;

#ifdef KDTRACE_HOOKS
		/*
		 * If the systrace module has registered it's probe
		 * callback and if there is a probe active for the
		 * syscall 'entry', process the probe.
		 */
		if (systrace_probe_func != NULL && sa->callp->sy_entry != 0)
			(*systrace_probe_func)(sa->callp->sy_entry, sa->code,
			    sa->callp, sa->args, 0);
#endif

		AUDIT_SYSCALL_ENTER(sa->code, td);
		error = (sa->callp->sy_call)(td, sa->args);
		AUDIT_SYSCALL_EXIT(error, td);

		/* Save the latest error return value. */
		td->td_errno = error;

#ifdef KDTRACE_HOOKS
		/*
		 * If the systrace module has registered it's probe
		 * callback and if there is a probe active for the
		 * syscall 'return', process the probe.
		 */
		if (systrace_probe_func != NULL && sa->callp->sy_return != 0)
			(*systrace_probe_func)(sa->callp->sy_return, sa->code,
			    sa->callp, NULL, (error) ? -1 : td->td_retval[0]);
#endif
		syscall_thread_exit(td, sa->callp);
		CTR4(KTR_SYSC, "syscall: p=%p error=%d return %#lx %#lx",
		    p, error, td->td_retval[0], td->td_retval[1]);
	}
 retval:
	if (traced) {
		PROC_LOCK(p);
		td->td_dbgflags &= ~TDB_SCE;
		PROC_UNLOCK(p);
	}
	(p->p_sysent->sv_set_syscall_retval)(td, error);
	return (error);
}
Beispiel #3
0
void
unix_syscall64(x86_saved_state_t *state)
{
	thread_t	thread;
	void			*vt;
	unsigned int	code;
	struct sysent	*callp;
	int		args_in_regs;
	boolean_t	args_start_at_rdi;
	int		error;
	struct proc	*p;
	struct uthread	*uthread;
	x86_saved_state64_t *regs;

	assert(is_saved_state64(state));
	regs = saved_state64(state);
#if	DEBUG
	if (regs->rax == 0x2000800)
		thread_exception_return();
#endif
	thread = current_thread();
	uthread = get_bsdthread_info(thread);

	/* Get the approriate proc; may be different from task's for vfork() */
	if (__probable(!(uthread->uu_flag & UT_VFORK)))
		p = (struct proc *)get_bsdtask_info(current_task());
	else 
		p = current_proc();

	/* Verify that we are not being called from a task without a proc */
	if (__improbable(p == NULL)) {
		regs->rax = EPERM;
		regs->isf.rflags |= EFL_CF;
		task_terminate_internal(current_task());
		thread_exception_return();
		/* NOTREACHED */
	}

	code = regs->rax & SYSCALL_NUMBER_MASK;
	DEBUG_KPRINT_SYSCALL_UNIX(
		"unix_syscall64: code=%d(%s) rip=%llx\n",
		code, syscallnames[code >= NUM_SYSENT ? 63 : code], regs->isf.rip);
	callp = (code >= NUM_SYSENT) ? &sysent[63] : &sysent[code];

	vt = (void *)uthread->uu_arg;

	if (__improbable(callp == sysent)) {
	        /*
		 * indirect system call... system call number
		 * passed as 'arg0'
		 */
		code = regs->rdi;
		callp = (code >= NUM_SYSENT) ? &sysent[63] : &sysent[code];
		args_start_at_rdi = FALSE;
		args_in_regs = 5;
	} else {
		args_start_at_rdi = TRUE;
		args_in_regs = 6;
	}

	if (callp->sy_narg != 0) {
		assert(callp->sy_narg <= 8); /* size of uu_arg */

		args_in_regs = MIN(args_in_regs, callp->sy_narg);
		memcpy(vt, args_start_at_rdi ? &regs->rdi : &regs->rsi, args_in_regs * sizeof(syscall_arg_t));


		if (code != 180) {
			uint64_t *ip = (uint64_t *)vt;

			KERNEL_DEBUG_CONSTANT_IST(KDEBUG_TRACE, 
				BSDDBG_CODE(DBG_BSD_EXCP_SC, code) | DBG_FUNC_START,
				(int)(*ip), (int)(*(ip+1)), (int)(*(ip+2)), (int)(*(ip+3)), 0);
		}

		if (__improbable(callp->sy_narg > args_in_regs)) {
			int copyin_count;

			copyin_count = (callp->sy_narg - args_in_regs) * sizeof(syscall_arg_t);

			error = copyin((user_addr_t)(regs->isf.rsp + sizeof(user_addr_t)), (char *)&uthread->uu_arg[args_in_regs], copyin_count);
			if (error) {
				regs->rax = error;
				regs->isf.rflags |= EFL_CF;
				thread_exception_return();
				/* NOTREACHED */
			}
		}
	} else
		KERNEL_DEBUG_CONSTANT_IST(KDEBUG_TRACE,
			BSDDBG_CODE(DBG_BSD_EXCP_SC, code) | DBG_FUNC_START,
			0, 0, 0, 0, 0);

	/*
	 * Delayed binding of thread credential to process credential, if we
	 * are not running with an explicitly set thread credential.
	 */
	kauth_cred_uthread_update(uthread, p);

	uthread->uu_rval[0] = 0;
	uthread->uu_rval[1] = 0;
	uthread->uu_flag |= UT_NOTCANCELPT;
	uthread->syscall_code = code;

#ifdef JOE_DEBUG
        uthread->uu_iocount = 0;
        uthread->uu_vpindex = 0;
#endif

	AUDIT_SYSCALL_ENTER(code, p, uthread);
	error = (*(callp->sy_call))((void *) p, vt, &(uthread->uu_rval[0]));
	AUDIT_SYSCALL_EXIT(code, p, uthread, error);

#ifdef JOE_DEBUG
        if (uthread->uu_iocount)
               printf("system call returned with uu_iocount != 0\n");
#endif

#if CONFIG_DTRACE
	uthread->t_dtrace_errno = error;
#endif /* CONFIG_DTRACE */
	
	if (__improbable(error == ERESTART)) {
		/*
		 * all system calls come through via the syscall instruction
		 * in 64 bit mode... its 2 bytes in length
		 * move the user's pc back to repeat the syscall:
		 */
		pal_syscall_restart( thread, state );
	}
	else if (error != EJUSTRETURN) {
		if (__improbable(error)) {
			regs->rax = error;
			regs->isf.rflags |= EFL_CF;	/* carry bit */
		} else { /* (not error) */

			switch (callp->sy_return_type) {
			case _SYSCALL_RET_INT_T:
				regs->rax = uthread->uu_rval[0];
				regs->rdx = uthread->uu_rval[1];
				break;
			case _SYSCALL_RET_UINT_T:
				regs->rax = ((u_int)uthread->uu_rval[0]);
				regs->rdx = ((u_int)uthread->uu_rval[1]);
				break;
			case _SYSCALL_RET_OFF_T:
			case _SYSCALL_RET_ADDR_T:
			case _SYSCALL_RET_SIZE_T:
			case _SYSCALL_RET_SSIZE_T:
			case _SYSCALL_RET_UINT64_T:
			        regs->rax = *((uint64_t *)(&uthread->uu_rval[0]));
				regs->rdx = 0;
				break;
			case _SYSCALL_RET_NONE:
				break;
			default:
				panic("unix_syscall: unknown return type");
				break;
			}
			regs->isf.rflags &= ~EFL_CF;
		} 
	}

	DEBUG_KPRINT_SYSCALL_UNIX(
		"unix_syscall64: error=%d retval=(%llu,%llu)\n",
		error, regs->rax, regs->rdx);
	
	uthread->uu_flag &= ~UT_NOTCANCELPT;

	if (__improbable(uthread->uu_lowpri_window)) {
	        /*
		 * task is marked as a low priority I/O type
		 * and the I/O we issued while in this system call
		 * collided with normal I/O operations... we'll
		 * delay in order to mitigate the impact of this
		 * task on the normal operation of the system
		 */
		throttle_lowpri_io(1);
	}
	if (__probable(code != 180))
		KERNEL_DEBUG_CONSTANT_IST(KDEBUG_TRACE, 
			BSDDBG_CODE(DBG_BSD_EXCP_SC, code) | DBG_FUNC_END,
			error, uthread->uu_rval[0], uthread->uu_rval[1], p->p_pid, 0);

	thread_exception_return();
	/* NOTREACHED */
}
void
ia32_syscall(struct trapframe *frame)
{
	caddr_t params;
	int i;
	struct sysent *callp;
	struct thread *td = curthread;
	struct proc *p = td->td_proc;
	register_t orig_tf_rflags;
	int error;
	int narg;
	u_int32_t args[8];
	u_int64_t args64[8];
	u_int code;
	ksiginfo_t ksi;

	PCPU_INC(cnt.v_syscall);
	td->td_pticks = 0;
	td->td_frame = frame;
	if (td->td_ucred != p->p_ucred) 
		cred_update_thread(td);
	params = (caddr_t)frame->tf_rsp + sizeof(u_int32_t);
	code = frame->tf_rax;
	orig_tf_rflags = frame->tf_rflags;

	if (p->p_sysent->sv_prepsyscall) {
		/*
		 * The prep code is MP aware.
		 */
		(*p->p_sysent->sv_prepsyscall)(frame, args, &code, &params);
	} else {
		/*
		 * Need to check if this is a 32 bit or 64 bit syscall.
		 * fuword is MP aware.
		 */
		if (code == SYS_syscall) {
			/*
			 * Code is first argument, followed by actual args.
			 */
			code = fuword32(params);
			params += sizeof(int);
		} else if (code == SYS___syscall) {
			/*
			 * Like syscall, but code is a quad, so as to maintain
			 * quad alignment for the rest of the arguments.
			 * We use a 32-bit fetch in case params is not
			 * aligned.
			 */
			code = fuword32(params);
			params += sizeof(quad_t);
		}
	}

 	if (p->p_sysent->sv_mask)
 		code &= p->p_sysent->sv_mask;

 	if (code >= p->p_sysent->sv_size)
 		callp = &p->p_sysent->sv_table[0];
  	else
 		callp = &p->p_sysent->sv_table[code];

	narg = callp->sy_narg;

	/*
	 * copyin and the ktrsyscall()/ktrsysret() code is MP-aware
	 */
	if (params != NULL && narg != 0)
		error = copyin(params, (caddr_t)args,
		    (u_int)(narg * sizeof(int)));
	else
		error = 0;

	for (i = 0; i < narg; i++)
		args64[i] = args[i];

#ifdef KTRACE
	if (KTRPOINT(td, KTR_SYSCALL))
		ktrsyscall(code, narg, args64);
#endif
	CTR4(KTR_SYSC, "syscall enter thread %p pid %d proc %s code %d", td,
	    td->td_proc->p_pid, td->td_proc->p_comm, code);

	if (error == 0) {
		td->td_retval[0] = 0;
		td->td_retval[1] = frame->tf_rdx;

		STOPEVENT(p, S_SCE, narg);

		PTRACESTOP_SC(p, td, S_PT_SCE);

		AUDIT_SYSCALL_ENTER(code, td);
		error = (*callp->sy_call)(td, args64);
		AUDIT_SYSCALL_EXIT(error, td);
	}

	switch (error) {
	case 0:
		frame->tf_rax = td->td_retval[0];
		frame->tf_rdx = td->td_retval[1];
		frame->tf_rflags &= ~PSL_C;
		break;

	case ERESTART:
		/*
		 * Reconstruct pc, assuming lcall $X,y is 7 bytes,
		 * int 0x80 is 2 bytes. We saved this in tf_err.
		 */
		frame->tf_rip -= frame->tf_err;
		break;

	case EJUSTRETURN:
		break;

	default:
 		if (p->p_sysent->sv_errsize) {
 			if (error >= p->p_sysent->sv_errsize)
  				error = -1;	/* XXX */
   			else
  				error = p->p_sysent->sv_errtbl[error];
		}
		frame->tf_rax = error;
		frame->tf_rflags |= PSL_C;
		break;
	}

	/*
	 * Traced syscall.
	 */
	if (orig_tf_rflags & PSL_T) {
		frame->tf_rflags &= ~PSL_T;
		ksiginfo_init_trap(&ksi);
		ksi.ksi_signo = SIGTRAP;
		ksi.ksi_code = TRAP_TRACE;
		ksi.ksi_addr = (void *)frame->tf_rip;
		trapsignal(td, &ksi);
	}

	/*
	 * Check for misbehavior.
	 */
	WITNESS_WARN(WARN_PANIC, NULL, "System call %s returning",
	    (code >= 0 && code < SYS_MAXSYSCALL) ? freebsd32_syscallnames[code] : "???");
	KASSERT(td->td_critnest == 0,
	    ("System call %s returning in a critical section",
	    (code >= 0 && code < SYS_MAXSYSCALL) ? freebsd32_syscallnames[code] : "???"));
	KASSERT(td->td_locks == 0,
	    ("System call %s returning with %d locks held",
	    (code >= 0 && code < SYS_MAXSYSCALL) ? freebsd32_syscallnames[code] : "???",
	    td->td_locks));

	/*
	 * Handle reschedule and other end-of-syscall issues
	 */
	userret(td, frame);

	CTR4(KTR_SYSC, "syscall exit thread %p pid %d proc %s code %d", td,
	    td->td_proc->p_pid, td->td_proc->p_comm, code);
#ifdef KTRACE
	if (KTRPOINT(td, KTR_SYSRET))
		ktrsysret(code, error, td->td_retval[0]);
#endif

	/*
	 * This works because errno is findable through the
	 * register set.  If we ever support an emulation where this
	 * is not the case, this code will need to be revisited.
	 */
	STOPEVENT(p, S_SCX, code);
 
	PTRACESTOP_SC(p, td, S_PT_SCX);
}