schulung_tools: rename/modify malloc to avoid system()

A more complex but cleaner implementation of retrieving/printing
the stats has been implemented. The implementation is put into
a separate stats.c file so that the main program (malloc.) can
be easily reviewed to see what the program is doing.

Signed-off-by: John Ogness <john.ogness@linutronix.de>

1 files changed, 56 insertions, 0 deletions

diff --git a/schulung_tools/malloc/stats.c b/schulung_tools/malloc/stats.c
new file mode 100644
index 0000000..4b17323
--- /dev/null
+++ b/schulung_tools/malloc/stats.c
@@ -0,0 +1,56 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <fcntl.h>
+#include <time.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+void print_stats(int postcall)
+{
+	static struct timespec tp1;
+	static struct timespec tp2;
+	static int fd = -1;
+	char buf[32];
+	int virt;
+	int res;
+
+	if (fd == -1)
+		fd = open("/proc/self/statm", O_RDONLY);
+
+	if (!postcall) {
+		clock_gettime(CLOCK_MONOTONIC, &tp1);
+		return;
+	}
+
+	printf("    time=");
+	if (tp1.tv_sec && clock_gettime(CLOCK_MONOTONIC, &tp2) == 0) {
+		if (tp1.tv_nsec > tp2.tv_nsec) {
+			tp2.tv_sec--;
+			tp2.tv_nsec += 1000000000;
+		}
+		tp2.tv_sec -= tp1.tv_sec;
+		tp2.tv_nsec -= tp1.tv_nsec;
+		printf("%d.%06ds ", tp2.tv_sec, tp2.tv_nsec / 1000);
+	} else {
+		tp2.tv_sec = 0;
+		printf("? ");
+	}
+	tp1 = tp2;
+
+	if (fd < 0)
+		goto out;
+
+	lseek(fd, 0, SEEK_SET);
+	if (read(fd, buf, sizeof(buf)) <= 0)
+		goto out;
+
+	if (sscanf(buf, "%d %d ", &virt, &res) != 2)
+		goto out;
+
+	printf("virt=%dKB res=%dKB", virt * 4, res * 4);
+out:
+	printf("\n");
+	fflush(stdout);
+}