2 files changed, 64 insertions, 0 deletions
diff --git a/user/monitor_user.c b/user/monitor_user.c
new file mode 100644
index 0000000..91da839
--- /dev/null
+++ b/user/monitor_user.c
@@ -0,0 +1,44 @@
+#include "monitor_user.h"
+#include <fcntl.h>
+#include <stdio.h>
+#include <sys/ioctl.h>
+#include <unistd.h>
+
+#define DEVICE "/dev/variable_monitor"
+int file_desc = -1;
+
+/// @brief start watch
+/// @param w_arg
+/// @return 0 means success, other means fail
+int start_watch(watch_arg w_arg) {
+  if (file_desc < 0) {
+    file_desc = open(DEVICE, 0);
+  }
+  if (file_desc < 0) {
+    printf("Can't open device file: %s\n", DEVICE);
+    return -1;
+  }
+
+  if (ioctl(file_desc, 1, &w_arg) < 0) {
+    printf("ioctl failed\n");
+    close(file_desc);
+    return -1;
+  }
+  return 0;
+}
+
+/// @brief cancel watch
+/// @return 0 means success, other means fail
+int cancel_watch() {
+  if (file_desc < 0) {
+    file_desc = open(DEVICE, 0);
+  }
+  if (file_desc < 0) {
+    printf("Device not open: %s,%d \n", DEVICE, file_desc);
+    return file_desc;
+  }
+
+  close(file_desc);
+  file_desc = -1;
+  return 0;
+}
diff --git a/user/monitor_user.h b/user/monitor_user.h
new file mode 100644
index 0000000..f4d9df1
--- /dev/null
+++ b/user/monitor_user.h
@@ -0,0 +1,20 @@
+// monitor_interface.h
+#include <sys/types.h>
+
+#define MAX_NAME_LEN (15) // max name length
+typedef struct {
+  pid_t task_id;               // current process id
+  char name[MAX_NAME_LEN + 1]; // name
+  void *ptr;                   // virtual address
+  int length_byte;             // byte
+  long long threshold;         // threshold value
+  unsigned char unsigned_flag; // unsigned flag (true: unsigned, false: signed)
+  unsigned char greater_flag;  // reverse flag (true: >, false: <)
+  unsigned long time_ns;       // timer interval (ns)
+} watch_arg;
+
+// start watch
+int start_watch(watch_arg w_arg);
+
+// cancel watch
+int cancel_watch(void);
+\ No newline at end of file