Add: rpath resolve

research/custom_loader/b.cc

@@ -72,17 +72,18 @@ struct libcache {
   void *main;
   void *thislib;
   void *libdyld;
+
+  int nrpath;
+  char** rpaths;
 };
 
-// try these hashes
+uint32_t fnv_hash_extend(const char *str, uint32_t h) {
-// https://gist.github.com/sgsfak/9ba382a0049f6ee885f68621ae86079b
-uint32_t fnv_hash(const char *str) {
   unsigned char *s = (unsigned char *)str; /* unsigned string */
 
   /* See the FNV parameters at www.isthe.com/chongo/tech/comp/fnv/#FNV-param */
   const uint32_t FNV_32_PRIME = 0x01000193; /* 16777619 */
 
-  uint32_t h = 0x811c9dc5; /* 2166136261 */
+  // uint32_t h = 0x811c9dc5; /* 2166136261 */x
   while (*s != 0) {
     /* xor the bottom with the current octet */
     h ^= *s++;
@@ -92,6 +93,12 @@ uint32_t fnv_hash(const char *str) {
 
   return h;
 }
+uint32_t fnv_hash(const char* str) {
+  return fnv_hash_extend(str, 0x811c9dc5);
+}
+
+// try these hashes
+// https://gist.github.com/sgsfak/9ba382a0049f6ee885f68621ae86079b
 
 // calculate the hash to search
 // _dyld_get_image_name returns the full path to the library
@@ -115,7 +122,20 @@ uint32_t calculate_libname_hash(const libcache *cache, const char *name) {
     // then resolve the full path for all rpath
     //
     // which rpath is correct can be done by checking if the cache has that hash
-    printf("resolver for @rpath is not supported yet\n");
+    for (int i = 0; i < cache->nrpath; i++){
+      char* rpath = cache->rpaths[i];
+      char* p = realpath(rpath, 0);
+      hash = hash_func(p);
+      hash = fnv_hash_extend(&name[6], hash);
+      for (size_t i = 0; i < cache->size; i++) {
+        if (cache->libs[i].hash == hash) {
+          free(p);
+          return hash;
+        }
+      }
+      free(p);
+    }
+    // printf("resolver for @rpath is not supported yet\n");
   } else {
     hash = hash_func(name);
   }
@@ -745,6 +765,7 @@ struct ProgramVars {
 
 void build_cache(struct libcache &cache, void *main);
 void fix(struct libcache &cache);
+void find_all_rpath(struct libcache &cache, void *main);
 
 void test(struct libcache &cache);
 
@@ -832,6 +853,7 @@ void build_cache(struct libcache &cache, void *main) {
   printf("lib header at %p\n", thislib);
   printf("libdyld header at %p\n", libdyld);
 
+  find_all_rpath(cache ,main);
   uint32_t trie_size;
   void *libdyld_export_trie = get_export_trie(libdyld, trie_size);
 
@@ -863,6 +885,41 @@ void build_cache(struct libcache &cache, void *main) {
   }
 }
 
+// Function to find all rpath entries of the main executable
+void find_all_rpath(struct libcache &cache, void *header) {
+  const uint32_t magic = *(uint32_t *)header;
+  char *ptr = (char *)header;
+  if (magic == magic64) {
+    ptr += 0x20;
+  } else {
+    ptr += 0x20 - 0x4;
+  }
+  printf("xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx\n");
+  const uint32_t ncmds = *((uint32_t *)header + 4);
+  printf("RPATHS:\n");
+  cache.nrpath = 0;
+  for (uint32_t i = 0; i < ncmds; i++) {
+    const uint32_t cmd = *((uint32_t *)ptr + 0);
+    const uint32_t cmdsize = *((uint32_t *)ptr + 1);
+    if (cmd == LC_RPATH) cache.nrpath++;
+    ptr += cmdsize;
+  }
+  uint32_t idx = 0;
+  ptr = (char *)header;
+  ptr += (magic == magic64) ? 0x20 : 0x20 - 0x4;
+  cache.rpaths = (char **)malloc(sizeof(char *) * cache.nrpath);
+  for (uint32_t i = 0; i < ncmds; i++) {
+    const uint32_t cmd = *((uint32_t *)ptr + 0);
+    const uint32_t cmdsize = *((uint32_t *)ptr + 1);
+    if (cmd == LC_RPATH) {
+      cache.rpaths[idx++] = (char *)ptr + 12;
+      printf("%s\n", cache.rpaths[idx - 1]);
+    }
+    ptr += cmdsize;
+  }
+  printf("xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx\n");
+}
+
 void fix_binds(struct libcache_item *libfixing, struct libcache *cache,
                int n_ins, uint32_t *instructions, char *libs, char *symbols) {
   uint32_t libsystem_hash =