Import sources from 2011-03-30 iso image

1 files changed, 75 insertions, 0 deletions

diff --git a/sys/src/libc/9sys/nsec.c b/sys/src/libc/9sys/nsec.c
new file mode 100755
index 000000000..f0e981d04
--- /dev/null
+++ b/sys/src/libc/9sys/nsec.c
@@ -0,0 +1,75 @@
+#include <u.h>
+#include <libc.h>
+#include <tos.h>
+
+static uvlong order = 0x0001020304050607ULL;
+
+static void
+be2vlong(vlong *to, uchar *f)
+{
+	uchar *t, *o;
+	int i;
+
+	t = (uchar*)to;
+	o = (uchar*)&order;
+	for(i = 0; i < sizeof order; i++)
+		t[o[i]] = f[i];
+}
+
+static int fd = -1;
+static struct {
+	int	pid;
+	int	fd;
+} fds[64];
+
+vlong
+nsec(void)
+{
+	uchar b[8];
+	vlong t;
+	int pid, i, f, tries;
+
+	/*
+	 * Threaded programs may have multiple procs
+	 * with different fd tables, so we may need to open
+	 * /dev/bintime on a per-pid basis
+	 */
+
+	/* First, look if we've opened it for this particular pid */
+	pid = _tos->pid;
+	do{
+		f = -1;
+		for(i = 0; i < nelem(fds); i++)
+			if(fds[i].pid == pid){
+				f = fds[i].fd;
+				break;
+			}
+		tries = 0;
+		if(f < 0){
+			/* If it's not open for this pid, try the global pid */
+			if(fd >= 0)
+				f = fd;
+			else{
+				/* must open */
+				if((f = open("/dev/bintime", OREAD|OCEXEC)) < 0)
+					return 0;
+				fd = f;
+				for(i = 0; i < nelem(fds); i++)
+					if(fds[i].pid == pid || fds[i].pid == 0){
+						fds[i].pid = pid;
+						fds[i].fd = f;
+						break;
+					}
+			}
+		}
+		if(pread(f, b, sizeof b, 0) == sizeof b){
+			be2vlong(&t, b);
+			return t;
+		}
+		close(f);
+		if(i < nelem(fds))
+			fds[i].fd = -1;
+	}while(tries++ == 0);	/* retry once */
+	USED(tries);
+	return 0;
+}