Internal malloc and various improvements

include/comp_utils.h

@@ -0,0 +1,17 @@
+#ifndef _COMP_UTILS_H
+#define _COMP_UTILS_H
+
+#include <err.h>
+#include <stddef.h>
+#include <string.h>
+
+#include "cheriintrin.h"
+
+void *malloc(size_t);
+void
+free(void *);
+void *calloc(size_t, size_t);
+void *
+realloc(void *, size_t);
+
+#endif // _COMP_UTILS_H

include/compartment.h

@@ -47,30 +47,12 @@ comp_exec_out();
 extern void
 __clear_cache(void *, void *);
 
-// Number of instructions to inject at intercepted function call point
-// TODO ensure there is sufficient space for these, so we don't spill over
-#define INTERCEPT_INSTR_COUNT 5
-
 // Number of instructions required by the transition function
 #define COMP_TRANS_FN_INSTR_CNT 4
 
 extern void *__capability sealed_redirect_cap;
 extern void *__capability comp_return_caps[2];
 
-/* For a function to be intercepted, information required to insert the
- * redirect code and perform redirection
- *
- * TODO recheck this is properly used, or re-design into a more light-weight
- * approach with pre-given transition capabilities
- */
-struct InterceptPatch
-{
-    int *patch_addr;
-    int32_t instr[INTERCEPT_INSTR_COUNT];
-    uintptr_t comp_manager_cap_addr;
-    void *__capability manager_cap;
-};
-
 // Maximum size of an argument, in bytes
 #define COMP_ARG_SIZE 8
 
@@ -210,20 +192,14 @@ struct Compartment
 
     // Hardware info - maybe move
     size_t page_size;
-
-    // Misc
-    unsigned short curr_intercept_count;
-    struct InterceptPatch *intercept_patches;
 };
 
 int
 entry_point_cmp(const void *, const void *);
 struct Compartment *
 comp_init();
 struct Compartment *
-comp_from_elf(char *, char **, size_t, char **, void **, size_t, void *);
-void
-comp_add_intercept(struct Compartment *, uintptr_t, uintptr_t);
+comp_from_elf(char *, char **, size_t, void *);
 void
 comp_map(struct Compartment *);
 void

include/intercept.h

@@ -11,8 +11,6 @@
 
 #include "cheriintrin.h"
 
-#include "mem_mng.h"
-
 // Forward declarations
 struct Compartment;
 extern struct Compartment *loaded_comp;
@@ -21,6 +19,8 @@ exec_comp(struct Compartment *, char *, char **);
 struct Compartment *manager_get_compartment_by_id(size_t);
 
 extern void *__capability manager_ddc;
+extern void
+comp_exec_out();
 
 // Number of capabilities required to perform a transition
 #define COMP_RETURN_CAPS_COUNT 2
@@ -55,43 +55,7 @@ intercept_wrapper();
 void
 setup_intercepts();
 
-time_t
-intercepted_time(time_t *);
-FILE *
-intercepted_fopen(const char *, const char *);
-size_t
-intercepted_fread(void *__restrict, size_t, size_t, FILE *__restrict);
-size_t
-intercepted_fwrite(void *__restrict, size_t, size_t, FILE *__restrict);
-int
-intercepted_fclose(FILE *);
-int
-intercepted_getc(FILE *);
-int
-intercepted_fputc(int, FILE *);
-int
-intercepted___srget(FILE *);
-
-void *
-my_realloc(void *, size_t);
-void *my_malloc(size_t);
-void
-my_free(void *);
-int
-my_fprintf(FILE *, const char *, ...);
-
 size_t
 my_call_comp(size_t, char *, void *);
-static const struct FuncIntercept to_intercept_funcs[] = {
-    /* Mem funcs */
-    { "malloc", (void *) my_malloc, NULL },
-    { "realloc", (void *) my_realloc, NULL },
-    { "free", (void *) my_free, NULL },
-};
-//
-// Functions to be intercepted and associated data
-#define INTERCEPT_FUNC_COUNT                                                   \
-    sizeof(to_intercept_funcs) / sizeof(to_intercept_funcs[0])
-extern struct FuncIntercept comp_intercept_funcs[INTERCEPT_FUNC_COUNT];
 
 #endif // _INTERCEPT_H

include/manager.h

@@ -83,6 +83,4 @@ clean_compartment_config(struct CompEntryPointDef *, size_t);
  * Memory allocation
  ******************************************************************************/
 
-#include "mem_mng.h"
-
 #endif // _MANAGER_H

src/CMakeLists.txt

@@ -1,10 +1,13 @@
 # Compartment management library
 add_library(chcomp STATIC
     manager.c
-    mem_mng.c
     compartment.c
     intercept.c
     transition.S
     )
 target_include_directories(chcomp PRIVATE ${INCLUDE_DIR} ${TOML_INCLUDE_DIR})
 target_link_libraries(chcomp PRIVATE tomllib)
+
+add_library(computils SHARED
+    comp_utils.c)
+target_include_directories(computils PRIVATE ${INCLUDE_DIR})

src/comp_utils.c

@@ -0,0 +1,46 @@
+#include "comp_utils.h"
+
+static void *malloc_ptr;
+static size_t heap_mem_left;
+
+void *
+malloc(size_t to_alloc)
+{
+    if (!malloc_ptr)
+    {
+        void *__capability ddc = cheri_ddc_get();
+        malloc_ptr = (char *) cheri_address_get(ddc);
+        heap_mem_left = cheri_length_get(ddc) - cheri_offset_get(ddc);
+    }
+    if (to_alloc > heap_mem_left)
+    {
+        errx(1, "Insufficient heap space left.");
+    }
+    void *to_ret = malloc_ptr;
+    memset(to_ret, 0, to_alloc);
+    malloc_ptr = (char *) malloc_ptr + to_alloc;
+    heap_mem_left -= to_alloc;
+    return to_ret;
+}
+
+void
+free(void *to_free)
+{
+    // TODO temp usage for bump allocator implementation to satisfy compiler
+    to_free = to_free;
+}
+
+void *
+calloc(size_t elem_count, size_t elem_size)
+{
+    return malloc(elem_count * elem_size);
+}
+
+void *
+realloc(void *to_realloc, size_t new_size)
+{
+    // TODO temp usage for bump allocator implementation to satisfy compiler
+    to_realloc = to_realloc;
+
+    return malloc(new_size);
+}