schulung_tools: add various demos and tools

Different tools have been used by various trainers as demos. Put
all these into master so they are available to all trainers.

ipc_pipe: ipc demo using pipes
ipc_shm: ipc demo using shared memory
libduma: source and instructions for compiling libduma
matrix: demo of good and bad cache access
mtrace: patch and infos for using mtrace with ASLR
rtex: demo of handling page faults

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

1 files changed, 49 insertions, 0 deletions

diff --git a/schulung_tools/ipc_shm/recv.c b/schulung_tools/ipc_shm/recv.c
new file mode 100644
index 0000000..8a08338
--- /dev/null
+++ b/schulung_tools/ipc_shm/recv.c
@@ -0,0 +1,49 @@
+#include <stdio.h>
+#include <pthread.h>
+#include <unistd.h>
+#include <errno.h>
+#include <sys/types.h>
+#include "shm.h"
+
+int main(void)
+{
+	struct share_data *data;
+	int rv;
+
+	if (create_share() != 0)
+		return 1;
+
+	data = get_share();
+	if (!data)
+		return 1;
+
+	init_share(data);
+
+	if (pthread_mutex_lock(&data->m) != 0)
+		return 1;
+
+	printf("recv (%d): waiting for signal\n", getpid());
+
+	do {
+		rv = pthread_cond_wait(&data->c, &data->m);
+		if (rv != 0) {
+			if (rv == EOWNERDEAD) {
+				printf("recv(%d): recover mutex\n", getpid());
+				data->msg[0] = 0;
+				pthread_mutex_consistent(&data->m);
+			} else {
+				/* maybe rv == ENOTRECOVERABLE */
+				return 1;
+			}
+		}
+	} while (rv != 0);
+
+	/* set "received" uprobe here */
+
+	printf("recv (%d): received signal: %s\n", getpid(), data->msg);
+	pthread_mutex_unlock(&data->m);
+
+	remove_share();
+
+	return 0;
+}