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add tsemacquire syscall for go

--- a/sys/include/libc.h

+++ b/sys/include/libc.h

@@ -670,6 +670,7 @@

 extern	long	semrelease(long*, long);

 extern	int	sleep(long);

 extern	int	stat(char*, uchar*, int);

+extern	int	tsemacquire(long*, ulong);

 extern	Waitmsg*	wait(void);

 extern	int	waitpid(void);

 extern	long	write(int, void*, long);

--- a/sys/src/9/port/sysproc.c

+++ b/sys/src/9/port/sysproc.c

@@ -1034,6 +1034,50 @@

 	return 1;

 }

+/* Acquire semaphore or time-out */

+static int

+tsemacquire(Segment *s, long *addr, ulong ms)

+{

+	int acquired, timedout;

+	ulong t, elms;

+	Sema phore;

+

+	if(canacquire(addr))

+		return 1;

+	if(ms == 0)

+		return 0;

+	acquired = timedout = 0;

+	semqueue(s, addr, &phore);

+	for(;;){

+		phore.waiting = 1;

+		coherence();

+		if(canacquire(addr)){

+			acquired = 1;

+			break;

+		}

+		if(waserror())

+			break;

+		t = m->ticks;

+		tsleep(&phore, semawoke, &phore, ms);

+		elms = TK2MS(m->ticks - t);

+		poperror();

+		if(elms >= ms){

+			timedout = 1;

+			break;

+		}

+		ms -= elms;

+	}

+	semdequeue(s, &phore);

+	coherence();	/* not strictly necessary due to lock in semdequeue */

+	if(!phore.waiting)

+		semwakeup(s, addr, 1);

+	if(timedout)

+		return 0;

+	if(!acquired)

+		nexterror();

+	return 1;

+}

+

 long

 syssemacquire(ulong *arg)

 {

@@ -1051,6 +1095,25 @@

 	if(*addr < 0)

 		error(Ebadarg);

 	return semacquire(s, addr, block);

+}

+

+long

+systsemacquire(ulong *arg)

+{

+	long *addr;

+	ulong ms;

+	Segment *s;

+

+	validaddr(arg[0], sizeof(long), 1);

+	evenaddr(arg[0]);

+	addr = (long*)arg[0];

+	ms = arg[1];

+

+	if((s = seg(up, (ulong)addr, 0)) == nil)

+		error(Ebadarg);

+	if(*addr < 0)

+		error(Ebadarg);

+	return tsemacquire(s, addr, ms);

 }

 long

--- a/sys/src/9/port/systab.h

+++ b/sys/src/9/port/systab.h

@@ -52,6 +52,7 @@

 Syscall sysawait;

 Syscall syspread;

 Syscall syspwrite;

+Syscall systsemacquire;

 Syscall	sysdeath;

 Syscall *systab[]={

@@ -105,6 +106,7 @@

 	[AWAIT]		sysawait,

 	[PREAD]		syspread,

 	[PWRITE]	syspwrite,

+	[TSEMACQUIRE]	systsemacquire,

 };

 char *sysctab[]={

@@ -158,6 +160,7 @@

 	[AWAIT]		"Await",

 	[PREAD]		"Pread",

 	[PWRITE]	"Pwrite",

+	[TSEMACQUIRE]	"Tsemacquire",

 };

 int nsyscall = (sizeof systab/sizeof systab[0]);

--- a/sys/src/libc/9syscall/sys.h

+++ b/sys/src/libc/9syscall/sys.h

@@ -48,3 +48,4 @@

 #define	AWAIT		47

 #define	PREAD		50

 #define	PWRITE		51

+#define	TSEMACQUIRE	52

-- 

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