ex4 done

diff --git a/ass3/mart/sws1-assignment3-s4109503-s4202015/exercise1.c b/ass3/mart/sws1-assignment3-s4109503-s4202015/exercise1.c
index 28d6a2c..2baefbc 100644 (file)
--- a/ass3/mart/sws1-assignment3-s4109503-s4202015/exercise1.c
+++ b/ass3/mart/sws1-assignment3-s4109503-s4202015/exercise1.c
@@ -1,14 +1,11 @@
 #include <stdio.h>
 #include <stdint.h>
 #include "magicfunction.h"
-
 #define MAX 4194304/sizeof(uint64_t)
-
 uint64_t determine_start()
 {
        return 0x567856785678;
 }
-
 int main(void)
 {
        uint64_t filler = 0x123412341234;
@@ -18,19 +15,16 @@ int main(void)
        /*Fill the stack with a filler value*/
        for(p = &stack -1; p >= &stack - 1 - MAX; p--)
                *p = filler;
-
        /*Find the beginning of the function stack with the function*/
        determine_start();
        for(q = &stack -1; q>=&stack-1-MAX; q--)
                if(*q == 0x567856785678)
                        break;
-       
        /*Run the function and find the last occurance of non stack filler */
        magic_function();
        for(p = &stack - 1 - MAX; p <= q; p++)
                if(*p != filler)
                        break;
-
        printf("%td byte stack size used\n", (char*)p-(char*)q);
        return 0;
 }

diff --git a/ass4/mart/sws1-assignment4-s4109503-s4202015/exercise1.c b/ass4/mart/sws1-assignment4-s4109503-s4202015/exercise1.c
index b361d09..2615c75 100644 (file)
--- a/ass4/mart/sws1-assignment4-s4109503-s4202015/exercise1.c
+++ b/ass4/mart/sws1-assignment4-s4109503-s4202015/exercise1.c
@@ -8,4 +8,5 @@ int main(void)
        for(size_t i = 1 << 31; i >= 1; i /= 2, free(b))
                d = (b = malloc(block += d * i)) == NULL ? -1 : 1;
        printf("One malloc can allocate at most %zu bytes\n", block);
+       return 0;
 }

diff --git a/ass4/mart/sws1-assignment4-s4109503-s4202015/exercise2.c b/ass4/mart/sws1-assignment4-s4109503-s4202015/exercise2.c
new file mode 100644 (file)
index 0000000..4343e61
--- /dev/null
+++ b/ass4/mart/sws1-assignment4-s4109503-s4202015/exercise2.c
@@ -0,0 +1,28 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+void heap_attack(void)
+{
+       char *b = malloc(1);
+       while(memcmp(--b, "s4109503", 8) != 0);
+       b += 8;
+       while(memcmp(b, "s4202015", 8) != 0)
+               *b++ = ' ';
+}
+
+int  main(void)
+{
+       char *s1 = malloc(8);
+       if(s1 == NULL)
+               return -1;
+       char *s2 = malloc(8);
+       if(s2 == NULL)
+               return -1;
+       strcpy(s1, "s4109503");
+       strcpy(s2, "s4202015");
+       heap_attack();
+       printf("student 1: \"%s\"\n", s1);
+       printf("student 2: \"%s\"\n", s2);
+       return 0;
+}

diff --git a/ass4/mart/sws1-assignment4-s4109503-s4202015/exercise2c b/ass4/mart/sws1-assignment4-s4109503-s4202015/exercise2c
new file mode 100644 (file)
index 0000000..39e2602
--- /dev/null
+++ b/ass4/mart/sws1-assignment4-s4109503-s4202015/exercise2c
@@ -0,0 +1 @@
+Strings are null terminated, therefore the 8th byte is \0

diff --git a/ass4/mart/sws1-assignment4-s4109503-s4202015/exercise2e b/ass4/mart/sws1-assignment4-s4109503-s4202015/exercise2e
new file mode 100644 (file)
index 0000000..b0e6e7a
--- /dev/null
+++ b/ass4/mart/sws1-assignment4-s4109503-s4202015/exercise2e
@@ -0,0 +1,3 @@
+It will deallocate the space and the next allocation could be not in the
+neighbourhood of the first(that is free'd). It might get overwritten too, and
+therefore you might not be able to find it anymore.

diff --git a/ass4/mart/sws1-assignment4-s4109503-s4202015/exercise3.c b/ass4/mart/sws1-assignment4-s4109503-s4202015/exercise3.c
new file mode 100644 (file)
index 0000000..f97359c
--- /dev/null
+++ b/ass4/mart/sws1-assignment4-s4109503-s4202015/exercise3.c
@@ -0,0 +1,42 @@
+#include <stdlib.h>
+#include <stdio.h>
+
+int main(void) /* https://www.kernel.org/doc/Documentation/CodingStyle */
+{
+       int i;
+       int j;
+       unsigned long long **m;
+       unsigned long long **mt;
+
+       while(1){
+               m = malloc(1000*sizeof(unsigned long long*));
+               if(m == NULL)
+                       return -1;
+               for(i = 0; i<1000; i++){
+                       m[i] = malloc(1000*sizeof(unsigned long long));
+                       if(m[i] == NULL)
+                               return -1;
+               }
+
+               mt = malloc(1000*sizeof(unsigned long long*));
+               if(mt == NULL)
+                       return -1;
+               for(i = 0; i<1000; i++){
+                       mt[i] = malloc(1000*sizeof(unsigned long long));
+                       if(mt[i] == NULL)
+                               return -1;
+               }
+
+               for(i = 0; i < 1000; i++)
+                       for(j = 0; j < 1000; j++)
+                               mt[i][j] = m[j][i];
+               
+               for(i = 0; i<1000; i++){
+                       free(m[i]);
+                       free(mt[i]);
+               }
+               free(m);
+               free(mt);
+       }
+       return 0;
+}

diff --git a/ass4/mart/sws1-assignment4-s4109503-s4202015/exercise3b b/ass4/mart/sws1-assignment4-s4109503-s4202015/exercise3b
new file mode 100644 (file)
index 0000000..4f230d2
--- /dev/null
+++ b/ass4/mart/sws1-assignment4-s4109503-s4202015/exercise3b
@@ -0,0 +1,2 @@
+We run out of space. The matrices are deallocated but the content isn't. It
+leaks memory.