/*?syscalls.c
?*?	Nachos?system?call?interface.??These?are?the?enveloped?Nachos?kernel?
?*??????operations?that?can?be?invoked?from?user?programs.
?*??????Each?NachOS?system?call?is?translated?to?an?apropriate?LIBC?call.?
?*??????Hopefully?this?works?on?MacOS?X?*nix?and?Windows
?*/


#include?“nachos_syscall.h“

#include?
#include?
#include?
#include?
#include?
#include?
#include?
#include?
#include?
#include?

#include?
#include?
#include?



#ifdef?HAVE_CONFIG_H
#include?“config.h“
#endif

#define?SHELL?“/bin/sh“

/*
?*?The?system?call?interface.??These?are?the?operations?the?Nachos
?*?kernel?needs?to?support?to?be?able?to?run?user?programs.
?*/

/*?Stop?Nachos?and?print?out?performance?stats?*/
void?Halt（）
{
	Exit（0）;
}
?
?
/*
?*?Add?the?two?operants?and?return?the?result
?*/?

int?Add（int?op1?int?op2）
{?
	return?op1?+?op2;
}


/*?This?user?program?is?done?（status?=?0?means?exited?normally）.?*/
void?Exit（int?status）
{
	exit（status）;
}

/*?Address?space?control?operations:?Exit?Exec?Execv?and?Join?*/

/*?Run?the?specified?executable?with?no?args?*/
/*?This?can?be?implemented?as?a?call?to?ExecV.
?*/?
SpaceId?Exec（char*?exec_name）
{
????pid_t?child;
????child?=?vfork（）;
????if（child?==?0）
????{
	execl?（SHELL?SHELL?“-c“?exec_name?NULL）;
	_exit?（EXIT_FAILURE）;
????}
????else?if（child?	return?EPERM;
????return?（SpaceId）?child;
}


/*?
?*?Run?the?executable?stored?in?the?Nachos?file?“argv[0]“?with
?*?parameters?stored?in?argv[1..argc-1]?and?return?the?
?*?address?space?identifier
?*?For?this?the?incoming?string?has?to?be?seperated?by?replacing?“?“?
?*?with?“\n“?and?building?the?appropriate?pointer?structure?argv.
?*/
SpaceId?ExecV（int?argc?char*?argv[]）
{
????pid_t?child;
????child?=?vfork（）;
????if（child?==?0）{
	execl?（SHELL?SHELL?“-c“?argv?NULL）;
	_exit?（EXIT_FAILURE）;
????}
????else?if（child?	return?EPERM;
????return?（SpaceId）?child;
}

/*?Only?return?once?the?user?program?“id“?has?finished.??
?*?Return?the?exit?status.
?*/
int?Join（SpaceId?id）
{
????return?waitpid（（pid_t）?id?（int*）?0?0）;
}
?

/*?File?system?operations:?Create?Remove?Open?Read?Write?Close
?*?These?functions?are?patterned?after?UNIX?--?files?represent
?*?both?files?*and*?hardware?I/O?devices.
?*
?*?Note?that?the?Nachos?file?system?has?a?stub?implementation?which
?*?can?be?used?to?support?these?system?calls?if?the?regular?Nachos
?*?file?system?has?not?been?implemented.
?*/
?

/*?when?an?address?space?starts?up?it?has?two?open?files?representing?
?*?keyboard?input?and?display?output?（in?UNIX?terms?stdin?and?stdout）.
?*?Read?and?Write?can?be?used?directly?on?these?without?first?opening
?*?the?console?device.
?*/

/*?Create?a?Nachos?file?with?name?“name“?*/
/*?Note:?Create?does?not?open?the?file.???*/
/*?Return?1?on?success?negative?error?code?on?failure?*/
int?Create（char?*name）
{
????int?fd;
????fd=open（

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----

?????文件????1169856??2010-05-08?02:24??5070369042杜星_NachOS實驗報告一.docx

?????文件?????187752??2002-12-16?18:57??NachOS-4.1\c++example\c++.ps

?????文件??????66890??2002-12-16?18:57??NachOS-4.1\c++example\c++.tex

?????文件???????1224??2002-12-16?18:57??NachOS-4.1\c++example\copyright.h

?????文件???????6276??2002-12-16?18:57??NachOS-4.1\c++example\inheritstack.cc

?????文件???????3026??2002-12-16?18:57??NachOS-4.1\c++example\inheritstack.h

?????文件???????3604??2002-12-16?18:57??NachOS-4.1\c++example\list.cc

?????文件????????919??2002-12-16?18:57??NachOS-4.1\c++example\list.h

?????文件????????706??2002-12-16?18:57??NachOS-4.1\c++example\Makefile

?????文件???????3569??2002-12-16?18:57??NachOS-4.1\c++example\stack.cc

?????文件???????1399??2002-12-16?18:57??NachOS-4.1\c++example\stack.h

?????文件???????3921??2002-12-16?18:57??NachOS-4.1\c++example\templatestack.cc

?????文件???????1252??2002-12-16?18:57??NachOS-4.1\c++example\templatestack.h

?????文件??????12006??2003-10-11?00:40??NachOS-4.1\code\build.cygwin\Makefile

?????文件??????31309??2002-12-16?18:57??NachOS-4.1\code\build.cygwin\Makefile.dep

?????文件??????61128??2010-05-07?22:53??NachOS-4.1\code\build.linux\addrspace.o

?????文件??????56480??2010-05-07?22:52??NachOS-4.1\code\build.linux\alarm.o

?????文件??????45920??2010-05-07?22:52??NachOS-4.1\code\build.linux\bitmap.o

?????文件??????62512??2010-05-07?22:52??NachOS-4.1\code\build.linux\console.o

?????文件??????38552??2010-05-07?22:52??NachOS-4.1\code\build.linux\debug.o

?????文件??????48516??2010-05-07?22:53??NachOS-4.1\code\build.linux\directory.o

?????文件??????65512??2010-05-07?22:52??NachOS-4.1\code\build.linux\disk.o

?????文件?????131076??2010-05-07?22:53??NachOS-4.1\code\build.linux\DISK_0

?????文件??????51948??2010-05-07?22:53??NachOS-4.1\code\build.linux\exception.o

?????文件??????54500??2010-05-07?22:53??NachOS-4.1\code\build.linux\filehdr.o

?????文件????????848??2010-05-07?22:53??NachOS-4.1\code\build.linux\filesys.o

?????文件??????81604??2010-05-07?22:52??NachOS-4.1\code\build.linux\interrupt.o

?????文件??????62544??2010-05-07?22:52??NachOS-4.1\code\build.linux\kernel.o

?????文件?????103016??2010-05-07?22:52??NachOS-4.1\code\build.linux\libtest.o

?????文件??????57688??2010-05-07?22:52??NachOS-4.1\code\build.linux\machine.o

............此處省略166個文件信息