update related_info::lab0

related_info/lab0/lab0_ex4.md

@@ -7,6 +7,4 @@ If you get gcc's error, try to read make.log and fix the bugs.
 
 If gcc successed, then you will get a.out. 
 
-Try to answer below question. 
-
 

related_info/lab0/lab0_ex5.c

@@ -0,0 +1,12 @@
+void X(int b) {
+  if (b==1){
+    printf("X:: b is 1!\n");
+  }else{
+    printf("X:: b is not 1!\n");
+  }
+}
+
+int main(int argc, char * argv){
+    int a=2;
+    X(a);
+}

related_info/lab0/lab0_ex5.md

@@ -0,0 +1,19 @@
+#README
+analysis lab0_ex5
+```
+echo "compile and analysis lab0_ex5"
+echo "====================================="
+gcc -m32 -g -o lab0_ex5.exe lab0_ex5.c
+echo "====================================="
+echo "using objdump to decompile lab0_ex5"
+echo "====================================="
+objdump -S lab0_ex5.exe 
+echo "====================================="
+echo "using readelf to analyze lab0_ex5"
+echo "====================================="
+readelf -a lab0_ex5.exe
+echo "====================================="
+echo "using nm to analyze lab0_ex5"
+echo "====================================="
+nm lab0_ex5.exe
+```

related_info/lab0/lab0_ex6.c

@@ -0,0 +1,15 @@
+#include <stdio.h>
+#include <unistd.h>
+void main(void){
+  int child_status, exec_status;
+  int pid = fork(); //create a child
+  if (pid==0) {     // child continues here
+    printf("Child: EXEC lec7_1\n");
+    exec_status=execve("lec7_1",NULL,NULL);
+    printf("Child: Why would I execute?\n");
+  } else {           // parent continues here
+    printf("Parent: Whose your daddy?\n");
+    child_status=wait(pid);
+    printf("Parent: the child %d exit with %d\n",pid, child_status);
+  }
+}

related_info/lab0/lab0_ex6.md

@@ -0,0 +1,9 @@
+#README
+analysis lab0_ex6
+```
+echo "====================================="
+echo "compile and analysis lab0_ex6"
+echo "====================================="
+gcc -g -m32 -o lab0_ex6.exe lab0_ex6.c
+./lab0_ex6
+```