libc: add a, bad, malloc

userspace/libc.c

@@ -536,7 +536,7 @@ char readc()
     return syscall0(SYSCALL_ID_READ);
 }
 
-char readcBlock()
+char getchar()
 {
     char c = 0;
     do {
@@ -549,7 +549,7 @@ int readline(char *buf, int size)
 {
     int i = 0;
     for (; i < size - 1; i++) {
-        char key = readcBlock();
+        char key = getchar();
 
         if (key == '\n')
             break;
@@ -570,3 +570,24 @@ void *brk(void *addr)
 {
     return (void *)syscall1(SYSCALL_ID_BRK, (unsigned int)addr);
 }
+
+void *malloc(size_t size)
+{
+    void *heapTop     = 0;
+    static void *free = 0;
+
+    if (heapTop == 0) {
+        heapTop = brk(0);
+        free    = heapTop;
+    } else {
+        heapTop = brk(0);
+    }
+
+    if (free + size > heapTop) {
+        if (brk(heapTop + size))
+            return NULL;
+    }
+
+    free += size;
+    return (free - size);
+}

userspace/libc.h

@@ -10,6 +10,8 @@
     (((c) == ' ') || ((c) == '\t') || ((c) == '\f') || ((c) == '\n') || ((c) == '\r') ||      \
      ((c) == '\v'))
 #define isprint(c) ((' ' <= (c)) && ((c) <= '~'))
+#define EOF (-1)
+
 
 int memcmp(const void *s1, const void *s2, size_t n);
 void *memcpy(void *dest, const void *src, size_t n);
@@ -43,6 +45,7 @@ void _exit(int status);
 void yolo();
 int testSycall5(uint arg1, uint arg2, uint arg3, uint arg4, uint arg5);
 char readc();
-char readcBlock();
+char getchar();
 int readline(char *buf, int size);
 void *brk(void *addr);
+void *malloc(size_t size);