1 files changed, 101 insertions, 0 deletions
diff --git a/libgo/runtime/thread-linux.c b/libgo/runtime/thread-linux.c
new file mode 100644
index 00000000000..b51f4970d25
--- /dev/null
+++ b/libgo/runtime/thread-linux.c
@@ -0,0 +1,101 @@
+// Copyright 2009 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+#include "runtime.h"
+
+#include <errno.h>
+#include <string.h>
+#include <time.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <syscall.h>
+#include <linux/futex.h>
+
+typedef struct timespec Timespec;
+
+// Atomically,
+//	if(*addr == val) sleep
+// Might be woken up spuriously; that's allowed.
+// Don't sleep longer than ns; ns < 0 means forever.
+void
+runtime_futexsleep(uint32 *addr, uint32 val, int64 ns)
+{
+	Timespec ts, *tsp;
+
+	if(ns < 0)
+		tsp = nil;
+	else {
+		ts.tv_sec = ns/1000000000LL;
+		ts.tv_nsec = ns%1000000000LL;
+		// Avoid overflowdefs
+		if(ts.tv_sec > 1<<30)
+			ts.tv_sec = 1<<30;
+		tsp = &ts;
+	}
+
+	// Some Linux kernels have a bug where futex of
+	// FUTEX_WAIT returns an internal error code
+	// as an errno.  Libpthread ignores the return value
+	// here, and so can we: as it says a few lines up,
+	// spurious wakeups are allowed.
+	syscall(__NR_futex, addr, FUTEX_WAIT, val, tsp, nil, 0);
+}
+
+// If any procs are sleeping on addr, wake up at most cnt.
+void
+runtime_futexwakeup(uint32 *addr, uint32 cnt)
+{
+	int64 ret;
+
+	ret = syscall(__NR_futex, addr, FUTEX_WAKE, cnt, nil, nil, 0);
+
+	if(ret >= 0)
+		return;
+
+	// I don't know that futex wakeup can return
+	// EAGAIN or EINTR, but if it does, it would be
+	// safe to loop and call futex again.
+	runtime_printf("futexwakeup addr=%p returned %lld\n", addr, (long long)ret);
+	*(int32*)0x1006 = 0x1006;
+}
+
+static int32
+getproccount(void)
+{
+	int32 fd, rd, cnt, cpustrlen;
+	const char *cpustr;
+	const byte *pos;
+	byte *bufpos;
+	byte buf[256];
+
+	fd = open("/proc/stat", O_RDONLY|O_CLOEXEC, 0);
+	if(fd == -1)
+		return 1;
+	cnt = 0;
+	bufpos = buf;
+	cpustr = "\ncpu";
+	cpustrlen = strlen(cpustr);
+	for(;;) {
+		rd = read(fd, bufpos, sizeof(buf)-cpustrlen);
+		if(rd == -1)
+			break;
+		bufpos[rd] = 0;
+		for(pos=buf; (pos=(const byte*)strstr((const char*)pos, cpustr)) != nil; cnt++, pos++) {
+		}
+		if(rd < cpustrlen)
+			break;
+		memmove(buf, bufpos+rd-cpustrlen+1, cpustrlen-1);
+		bufpos = buf+cpustrlen-1;
+	}
+	close(fd);
+	return cnt ? cnt : 1;
+}
+
+void
+runtime_osinit(void)
+{
+	runtime_ncpu = getproccount();
+}