Research: Add mmap demo

trunk/research/frame/mmap0.cpp

@@ -0,0 +1,31 @@
+/*
+g++ mmap0.cpp -g -O0 -o mmap && ./mmap
+*/
+#include <stdio.h>
+#include <assert.h>
+#include <sys/mman.h>
+#include <string.h>
+
+int main(int argc, char** argv)
+{
+    int zero_fd = -1;
+    int size = 64 * 1024;
+    int mmap_flags = MAP_PRIVATE | MAP_ANON;
+    char* vaddr = (char*)mmap(NULL, size, PROT_READ | PROT_WRITE, mmap_flags, zero_fd, 0);
+    assert (vaddr != (void *)MAP_FAILED);
+    printf("vaddr=%p, size=%d\n", vaddr, size);
+
+    vaddr[0] = 0x0f;
+    printf("OK: access vaddr p[0]=%x\n", vaddr[0]);
+
+    int REDZONE = 4096;
+    mprotect(vaddr, REDZONE, PROT_NONE);
+    printf("protect vaddr=%p, [0, %d]\n", vaddr, REDZONE);
+
+    printf("try to access vaddr\n");
+    vaddr[0] = 0x0f;
+    printf("OK: access vaddr p[0]=%x\n", vaddr[0]);
+
+    return 0;
+}
+

trunk/research/frame/mmap1.cpp

@@ -0,0 +1,30 @@
+/*
+g++ mmap1.cpp -g -O0 -o mmap && ./mmap
+*/
+#include <stdio.h>
+#include <assert.h>
+#include <sys/mman.h>
+#include <string.h>
+
+int main(int argc, char** argv)
+{
+    int zero_fd = -1;
+    int size = 64 * 1024;
+    int mmap_flags = MAP_PRIVATE | MAP_ANON;
+    char* vaddr = (char*)mmap(NULL, size, PROT_READ | PROT_WRITE, mmap_flags, zero_fd, 0);
+    assert (vaddr != (void *)MAP_FAILED);
+    printf("vaddr=%p, size=%d\n", vaddr, size);
+
+    vaddr[0] = 0x0f;
+    printf("OK: access vaddr p[0]=%x\n", vaddr[0]);
+
+    munmap(vaddr, size);
+    printf("munmap vaddr=%p, size=%d\n", vaddr, size);
+
+    printf("try to access vaddr\n");
+    vaddr[0] = 0x0f;
+    printf("OK: access vaddr p[0]=%x\n", vaddr[0]);
+
+    return 0;
+}
+