1 compartment to N mappings

Move from a design of "one compartment has one mapping" to "one
compartment can be mapped multiple times". This involves "staging" a
compartment, with temporary internal relative relocations, after which
the staging can be lifted to a "mapping", which has correct relocations
and can be executed. This greatly reduces the overhead of creating the
same compartment multiple times.

* Remove some now unused functions

include/compartment.h

@@ -75,9 +75,7 @@ extern void *__capability comp_return_caps[2];
 struct SegmentMap
 {
     void *mem_bot;
-    void *mem_top;
     size_t offset;
-    ptrdiff_t correction;
     size_t mem_sz;
     size_t file_sz;
     int prot_flags;
@@ -97,6 +95,7 @@ struct LibRelaMapping
     unsigned short rela_sym_type; // type of underlying symbol
     unsigned short rela_sym_bind; // bind of underlying symbol
     uint16_t rela_sym_shndx; // section index of underlying symbol
+    bool mapping_reloc; // whether to relocate when mapped for execution
 };
 
 /**
@@ -106,7 +105,10 @@ struct LibDependency
 {
     char *lib_name;
     char *lib_path;
-    void *lib_mem_base;
+    void *lib_mem_base; // relative address in compartment
+
+    void *data_base; // address of data mapped in loader
+    size_t data_size; // size of mapped data
 
     // Segments of interest (usually, of type `PT_LOAD`) within this library
     size_t lib_segs_count;
@@ -127,6 +129,7 @@ struct LibDependency
     // TLS-related variables
     // TODO can there be more TLS sections?
     void *tls_sec_addr;
+    size_t tls_sec_off;
     size_t tls_sec_size;
     size_t tls_data_size;
     // offset from TLS base pointer (i.e., value of `tpidr_el0`) where this
@@ -167,7 +170,6 @@ struct CompConfig
     size_t stack_size;
     struct CompEntryPointDef *entry_points;
     size_t entry_point_count;
-    void *base_address;
 
     // Variables related to `manager.h` prepared `environ` data
     char **env_ptr; // pointer to `environ` array
@@ -186,12 +188,11 @@ struct Compartment
     size_t id;
     struct CompConfig *cc;
     // Execution info
-    void *__capability ddc;
     // ELF data
-    size_t size; // size of compartment in memory
-    void *base; // address where to load compartment
-    void *mem_top;
-    bool mapped;
+    size_t total_size; // size of compartment in memory
+    size_t data_size; // size of data segments of ELF files
+    void *staged_addr; // address where compartment data is stored, ready for
+                       // mapping
 
     // Environ
     char **environ_ptr;
@@ -223,7 +224,7 @@ entry_point_cmp(const void *, const void *);
 struct Compartment *
 comp_from_elf(char *, struct CompConfig *); // char **, size_t, void *);
 void
-comp_map(struct Compartment *);
+comp_map(struct Compartment *, void *);
 void
 comp_unmap(struct Compartment *);
 void
@@ -232,6 +233,8 @@ int64_t
 comp_exec(struct Compartment *, char *, void *, size_t);
 void
 comp_clean(struct Compartment *);
+void *
+get_seg_target(void *, struct LibDependency *, size_t);
 
 struct Compartment *
 find_comp(struct Compartment *);

include/intercept.h

@@ -9,7 +9,9 @@
 // vDSO wrapper needed includes
 #include <time.h>
 
+#ifdef __CHERI__
 #include "cheriintrin.h"
+#endif
 
 // Forward declarations
 struct Compartment;
@@ -55,7 +57,8 @@ intercept_wrapper();
 void
 setup_intercepts();
 
-size_t
-my_call_comp(size_t, char *, void *);
+// TODO Reimplement this for inter-compartment function calls
+// size_t
+// my_call_comp(size_t, char *, void *);
 
 #endif // _INTERCEPT_H

include/manager.h

@@ -31,12 +31,8 @@ extern struct Compartment *loaded_comp;
 // Compartment configuration file suffix
 extern const char *comp_config_suffix;
 
-void *
-get_next_comp_addr(void);
 struct Compartment *
 register_new_comp(char *, bool);
-int64_t
-exec_comp(struct Compartment *, char *, char **);
 
 union arg_holder
 {
@@ -57,7 +53,24 @@ void
 clean_compartment_config(struct CompEntryPointDef *, size_t);
 
 /*******************************************************************************
- * Memory allocation
+ * Compartment mappings
  ******************************************************************************/
 
+struct CompMapping *
+mapping_new(struct Compartment *);
+struct CompMapping *
+mapping_new_fixed(struct Compartment *, void *);
+void
+mapping_free(struct CompMapping *);
+int64_t
+mapping_exec(struct CompMapping *, char *, char **);
+
+struct CompMapping
+{
+    size_t id;
+    void *__capability ddc;
+    void *map_addr;
+    struct Compartment *comp;
+};
+
 #endif // _MANAGER_H