thesis: Complete 2.2

thesis/listings/intercept-preload.c

@@ -0,0 +1,35 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <string.h>
+#include <dlfcn.h>
+
+static void *(*__real_malloc)(size_t);
+
+static int mode = 0;
+
+static void fin(void) {
+    if (mode > 0) fprintf(stderr, "intercept: stopped\n");
+    mode = 0;
+}
+
+static void init(void) {
+    if (mode) return;
+    mode = -1;
+    if (((__real_malloc) = dlsym(RTLD_NEXT, "malloc")) == NULL) {
+        fprintf(stderr, "intercept: unable to load symbol '%s': %s",
+            "malloc", strerror(errno));
+        return;
+    }
+    atexit(fin);
+    fprintf(stderr, "intercept: intercepting function calls\n");
+    mode = 1;
+}
+
+void *malloc(size_t size) {
+    init();
+    // before call to malloc
+    void *ret = __real_malloc(size);
+    // after call to malloc
+    return ret;
+}

thesis/listings/intercept-wrap.c

@@ -0,0 +1,27 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+extern void *__real_malloc(size_t);
+
+static int mode = 0;
+
+static void fin(void) {
+    if (mode > 0) fprintf(stderr, "intercept: stopped\n");
+    mode = 0;
+}
+
+static void init(void) {
+    if (mode) return;
+    mode = -1;
+    atexit(fin);
+    fprintf(stderr, "intercept: intercepting function calls\n");
+    mode = 1;
+}
+
+void *__wrap_malloc(size_t size) {
+    init();
+    // before call to malloc
+    void *ret = __real_malloc(size);
+    // after call to malloc
+    return ret;
+}

thesis/listings/intercept.c

@@ -0,0 +1,47 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <string.h>
+#include <dlfcn.h>
+
+#ifdef INTERCEPT_PRELOAD
+#define load(name) \
+    if (((__real_ ## name) = dlsym(RTLD_NEXT, #name)) == NULL) { \
+        fprintf(stderr, "intercept: unable to load symbol '%s': %s", \
+            #name, strerror(errno)); \
+        return; \
+    }
+#define sym(name) name
+#define func_def(ret, name) static ret (*__real_ ## name)
+#else
+#define sym(name) __wrap_ ## name
+#define func_def(ret, name) extern ret __real_ ## name
+#endif
+
+func_def(void *, malloc)(size_t);
+
+static int mode = 0;
+
+static void fin(void) {
+    if (mode > 0) fprintf(stderr, "intercept: stopped\n");
+    mode = 0;
+}
+
+static void init(void) {
+    if (mode) return;
+    mode = -1;
+#ifdef INTERCEPT_PRELOAD
+    load(malloc);
+#endif
+    atexit(fin);
+    fprintf(stderr, "intercept: intercepting function calls\n");
+    mode = 1;
+}
+
+void *sym(malloc)(size_t size) {
+    init();
+    // before call to malloc
+    void *ret = __real_malloc(size);
+    // after call to malloc
+    return ret;
+}

thesis/listings/preload.c

@@ -0,0 +1,15 @@
+#include <stdlib.h>
+#include <dlfcn.h>
+#include <errno.h>
+
+void *malloc(size_t size) {
+    // before call to malloc
+    void *(*_malloc)(size_t);
+    if ((_malloc = dlsym(RTLD_NEXT, "malloc")) == NULL) {
+        errno = ENOSYS;
+        return NULL;
+    }
+    void *ret = _malloc(size);
+    // after call to malloc
+    return ret;
+}

thesis/listings/wrap.c

@@ -0,0 +1,10 @@
+#include <stddef.h>
+
+extern void *__real_malloc(size_t size);
+
+void *__wrap_malloc(size_t size) {
+    // before call to malloc
+    void *ret = __real_malloc(size);
+    // after call to malloc
+    return ret;
+}