fix optimization access_process_vm_atomic

diff --git a/kprobe/dbi_kprobes_deps.c b/kprobe/dbi_kprobes_deps.c
index a7c1cc9..3a9a533 100644 (file)
--- a/kprobe/dbi_kprobes_deps.c
+++ b/kprobe/dbi_kprobes_deps.c
@@ -737,13 +737,20 @@ int get_user_pages_uprobe(struct task_struct *tsk, struct mm_struct *mm,
 #endif
 }
 
+#define ACCESS_PROCESS_OPTIMIZATION 0
+
+#if ACCESS_PROCESS_OPTIMIZATION
+
+#define GET_STEP_X(LEN, STEP) (((LEN) >= (STEP)) ? (STEP) : (LEN) % (STEP))
+#define GET_STEP_4(LEN) GET_STEP_X((LEN), 4)
+
 static void read_data_current(unsigned long addr, void *buf, int len)
 {
        int step;
        int pos = 0;
 
-       for (step = len % 8; len; len -= step) {
-               switch (len & 0) {
+       for (step = GET_STEP_4(len); len; len -= step) {
+               switch (GET_STEP_4(len)) {
                case 1:
                        get_user(*(u8 *)(buf + pos), (unsigned long *)(addr + pos));
                        step = 1;
@@ -756,31 +763,23 @@ static void read_data_current(unsigned long addr, void *buf, int len)
                        break;
 
                case 4:
-               case 5:
-               case 6:
-               case 7: {
                        get_user(*(u32 *)(buf + pos), (unsigned long *)(addr + pos));
                        step = 4;
                        break;
                }
 
-               case 8:
-                       get_user(*(u64 *)(buf + pos), (unsigned long *)(addr + pos));
-                       step = 8;
-                       break;
-               }
-
                pos += step;
        }
 }
 
+// not working
 static void write_data_current(unsigned long addr, void *buf, int len)
 {
        int step;
        int pos = 0;
 
-       for (step = len % 8; len; len -= step) {
-               switch (len & 0) {
+       for (step = GET_STEP_4(len); len; len -= step) {
+               switch (GET_STEP_4(len)) {
                case 1:
                        put_user(*(u8 *)(buf + pos), (unsigned long *)(addr + pos));
                        step = 1;
@@ -793,25 +792,15 @@ static void write_data_current(unsigned long addr, void *buf, int len)
                        break;
 
                case 4:
-               case 5:
-               case 6:
-               case 7: {
                        put_user(*(u32 *)(buf + pos), (unsigned long *)(addr + pos));
                        step = 4;
                        break;
                }
 
-               case 8:
-                       put_user(*(u64 *)(buf + pos), (unsigned long *)(addr + pos));
-                       step = 8;
-                       break;
-               }
-
                pos += step;
        }
 }
-
-#define ACCESS_PROCESS_OPTIMIZATION 0
+#endif
 
 int access_process_vm_atomic(struct task_struct *tsk, unsigned long addr, void *buf, int len, int write)
 {
@@ -819,18 +808,13 @@ int access_process_vm_atomic(struct task_struct *tsk, unsigned long addr, void *
        struct vm_area_struct *vma;
        void *old_buf = buf;
 
-#if ACCESS_PROCESS_OPTIMIZATION
-       if (tsk == current) {
-               if (len <= 0) {
-                       return 0;
-               }
-
-               if (write) {
-                       write_data_current(addr, buf, len);
-               } else {
-                       read_data_current(addr, buf, len);
-               }
+       if (len <= 0) {
+               return -1;
+       }
 
+#if ACCESS_PROCESS_OPTIMIZATION
+       if (write == 0 && tsk == current) {
+               read_data_current(addr, buf, len);
                return len;
        }
 #endif