Initialize all function-level variables (#159)

* Initialize all function-level variables

* Fix formatting

* Fix error and found some more uninitialized variables

---------

Co-authored-by: Hariharan Devarajan <[email protected]>

Author: TomTheBear

src/elf_ops.c

@@ -48,9 +48,9 @@ static uint32_t gnu_hash_func(const char *str) {
 signed long lookup_gnu_hash_symbol(const char *name, ElfW(Sym) * syms,
                                    ElfW(Half) * versym, char *symnames,
                                    void *sheader) {
-  uint32_t *buckets, *vals;
-  uint32_t hash_val;
-  uint32_t cur_sym, cur_sym_hashval;
+  uint32_t *buckets = NULL, *vals = NULL;
+  uint32_t hash_val = 0;
+  uint32_t cur_sym = 0, cur_sym_hashval = 0;
   signed long latest_sym = -1;
   ElfW(Half) latest_sym_ver = 0;
   struct gnu_hash_header *header = (struct gnu_hash_header *)(sheader);
@@ -89,7 +89,7 @@ signed long lookup_gnu_hash_symbol(const char *name, ElfW(Sym) * syms,
 }
 
 static unsigned long elf_hash(const unsigned char *name) {
-  unsigned int h = 0, g;
+  unsigned int h = 0, g = 0;
   while (*name != '\0') {
     h = (h << 4) + *name++;
     if ((g = h & 0xf0000000)) {

src/gotcha.c

@@ -54,7 +54,7 @@ static void setInternalBindingAddressPointer(void **in, void *value) {
 
 long lookup_exported_symbol(const char *name, const struct link_map *lib,
                             void **symbol) {
-  long result;
+  long result = 0;
   if (is_vdso(lib)) {
     debug_printf(2, "Skipping VDSO library at 0x%lx with name %s\n",
                  lib->l_addr, LIB_NAME(lib));
@@ -96,8 +96,8 @@ long lookup_exported_symbol(const char *name, const struct link_map *lib,
 }
 
 int prepare_symbol(struct internal_binding_t *binding) {
-  int result;
-  struct link_map *lib;
+  int result = 0;
+  struct link_map *lib = NULL;
   struct gotcha_binding_t *user_binding = binding->user_binding;
 
   debug_printf(2, "Looking up exported symbols for %s\n", user_binding->name);
@@ -162,7 +162,7 @@ static int rewrite_wrapper_orders(struct internal_binding_t *binding) {
                insert_priority);
 
   struct internal_binding_t *head;
-  int hash_result;
+  int hash_result = 0;
   hash_result =
       lookup_hashtable(&function_hash_table, (void *)name, (void **)&head);
   if (hash_result != 0) {
@@ -209,9 +209,9 @@ static int rewrite_wrapper_orders(struct internal_binding_t *binding) {
 static int update_lib_bindings(ElfW(Sym) * symbol KNOWN_UNUSED, char *name,
                                ElfW(Addr) offset, struct link_map *lmap,
                                hash_table_t *lookuptable) {
-  int result;
-  struct internal_binding_t *internal_binding;
-  void **got_address;
+  int result = 0;
+  struct internal_binding_t *internal_binding = NULL;
+  void **got_address = NULL;
 
   result = lookup_hashtable(lookuptable, name, (void **)&internal_binding);
   if (result != 0) return -1;
@@ -391,7 +391,7 @@ static int update_library_got(struct link_map *map,
 }
 
 void update_all_library_gots(hash_table_t *bindings) {
-  struct link_map *lib_iter;
+  struct link_map *lib_iter = NULL;
   debug_printf(2, "Searching all callsites for %lu bindings\n",
                (unsigned long)bindings->entry_count);
   for (lib_iter = _r_debug.r_map; lib_iter != 0; lib_iter = lib_iter->l_next) {
@@ -402,9 +402,9 @@ void update_all_library_gots(hash_table_t *bindings) {
 GOTCHA_EXPORT enum gotcha_error_t gotcha_wrap(
     struct gotcha_binding_t *user_bindings, int num_actions,
     const char *tool_name) {
-  int i, not_found = 0, new_bindings_count = 0;
-  tool_t *tool;
-  hash_table_t new_bindings;
+  int i = 0, not_found = 0, new_bindings_count = 0;
+  tool_t *tool = NULL;
+  hash_table_t new_bindings = EMPTY_HASH_TABLE;
 
   gotcha_init();
 

src/gotcha_auxv.c

@@ -35,11 +35,11 @@ static unsigned int auxv_pagesz = 0;
 
 int parse_auxv_contents() {
   char name[] = "/proc/self/auxv";
-  int fd, done = 0;
-  char buffer[BUFFER_LEN];
+  int fd = -1, done = 0;
+  char buffer[BUFFER_LEN] = {'\0'};
   const ssize_t buffer_size = BUFFER_LEN;
-  ssize_t offset = 0, result;
-  ElfW(auxv_t) * auxv, *a;
+  ssize_t offset = 0, result = 0;
+  ElfW(auxv_t) *auxv = NULL, *a = NULL;
   static int parsed_auxv = 0;
 
   if (parsed_auxv) return parsed_auxv == -1 ? parsed_auxv : 0;
@@ -86,7 +86,7 @@ int parse_auxv_contents() {
 }
 
 struct link_map *get_vdso_from_auxv() {
-  struct link_map *m;
+  struct link_map *m = NULL;
 
   ElfW(Phdr) *vdso_phdrs = NULL;
   ElfW(Half) vdso_phdr_num, p;
@@ -114,16 +114,16 @@ struct link_map *get_vdso_from_auxv() {
 }
 
 unsigned int get_auxv_pagesize() {
-  int result;
+  int result = 0;
   result = parse_auxv_contents();
   return result == -1 ? 0 : auxv_pagesz;
 }
 
 static char *vdso_aliases[] = {"linux-vdso.so", "linux-gate.so", NULL};
 
 struct link_map *get_vdso_from_aliases() {
-  struct link_map *m;
-  char **aliases;
+  struct link_map *m = NULL;
+  char **aliases = NULL;
 
   for (m = _r_debug.r_map; m; m = m->l_next) {
     for (aliases = vdso_aliases; *aliases; aliases++) {
@@ -136,7 +136,7 @@ struct link_map *get_vdso_from_aliases() {
 }
 
 static int read_line(char *line, int size, int fd) {
-  int i;
+  int i = 0;
   for (i = 0; i < size - 1; i++) {
     int result = gotcha_read(fd, line + i, 1);
     if (result == -1 && errno == EINTR) continue;  // GCOVR_EXCL_LINE
@@ -201,10 +201,10 @@ static int read_word(char *str, char *word, int word_size) {
 }
 
 struct link_map *get_vdso_from_maps() {
-  int maps, hit_eof;
-  ElfW(Addr) addr_begin, addr_end, dynamic;
-  char name[BUFFER_LEN], line[BUFFER_LEN], *line_pos;
-  struct link_map *m;
+  int maps = 0, hit_eof = 0;
+  ElfW(Addr) addr_begin = 0, addr_end = 0, dynamic = 0;
+  char name[BUFFER_LEN] = {'\0'}, line[BUFFER_LEN] = {'\0'}, *line_pos = NULL;
+  struct link_map *m = NULL;
   maps = gotcha_open("/proc/self/maps", O_RDONLY);
   for (;;) {
     hit_eof = read_line(line, BUFFER_LEN, maps);
@@ -239,7 +239,7 @@ struct link_map *get_vdso_from_maps() {
 int is_vdso(const struct link_map *map) {
   static int vdso_checked = 0;
   static struct link_map *vdso = NULL;
-  struct link_map *result;
+  struct link_map *result = NULL;
 
   if (!map) return 0;
   if (vdso_checked) return (map == vdso);

src/gotcha_dl.c

@@ -15,6 +15,8 @@ struct Addrs {
   struct link_map *lmap;   // output
   int found;
 };
+#define EMPTY_ADDRS \
+  {0, NULL, 0}
 /**
  * This is a callback to get headers for each library.
  * We check if the caller's virtual address is between base address and the
@@ -29,7 +31,7 @@ struct Addrs {
 int lib_header_callback(struct dl_phdr_info *info, size_t size, void *data) {
   struct Addrs *addrs = data;
   const char *name = NULL;
-  ElfW(Addr) load_address;
+  ElfW(Addr) load_address = 0;
   for (int i = 0; i < info->dlpi_phnum; ++i) {
     if (info->dlpi_phdr[i].p_type == PT_LOAD) {
       ElfW(Addr) base_addr = info->dlpi_addr;
@@ -73,11 +75,11 @@ static struct link_map *gotchas_dlsym_rtld_next_lookup(const char *name,
   /* Iterative over the library headers and find the caller
    * the address of the caller is set in addrs->library_laddr
    **/
-  struct Addrs addrs;
+  struct Addrs addrs = EMPTY_ADDRS;
   addrs.lookup_addr = caller;
   addrs.lmap = _r_debug.r_map;
   addrs.found = 0;
-  void *symbol;
+  void *symbol = NULL;
   dl_iterate_phdr(lib_header_callback, &addrs);
   if (!addrs.found) {  // GCOVR_EXCL_START
     error_printf("RTLD_NEXT used in code not dynamically loaded");
@@ -106,7 +108,7 @@ gotcha_wrappee_handle_t orig_dlsym_handle;
 
 static int per_binding(hash_key_t key, hash_data_t data,
                        void *opaque KNOWN_UNUSED) {
-  int result;
+  int result = 0;
   struct internal_binding_t *binding = (struct internal_binding_t *)data;
 
   debug_printf(3, "Trying to re-bind %s from tool %s after dlopen\n",
@@ -136,7 +138,7 @@ static int per_binding(hash_key_t key, hash_data_t data,
 
 static void *dlopen_wrapper(const char *filename, int flags) {
   typeof(&dlopen_wrapper) orig_dlopen = gotcha_get_wrappee(orig_dlopen_handle);
-  void *handle;
+  void *handle = NULL;
   debug_printf(1, "User called dlopen(%s, 0x%x)\n", filename,
                (unsigned int)flags);
   handle = orig_dlopen(filename, flags);
@@ -154,7 +156,7 @@ static void *dlopen_wrapper(const char *filename, int flags) {
 static void *dlsym_wrapper(void *handle, const char *symbol_name) {
   typeof(&dlopen_wrapper) orig_dlopen = gotcha_get_wrappee(orig_dlopen_handle);
   typeof(&dlsym_wrapper) orig_dlsym = gotcha_get_wrappee(orig_dlsym_handle);
-  struct internal_binding_t *binding;
+  struct internal_binding_t *binding = NULL;
   debug_printf(1, "User called dlsym(%p, %s)\n", handle, symbol_name);
   int result = lookup_hashtable(&function_hash_table, (hash_key_t)symbol_name,
                                 (hash_data_t *)&binding);

src/gotcha_utils.c

@@ -28,7 +28,7 @@ int debug_level;
 static void debug_init() {
   static int debug_initialized = 0;
 
-  char *debug_str;
+  char *debug_str = NULL;
   if (debug_initialized) {
     return;  // GCOVR_EXCL_LINE
   }
@@ -48,9 +48,9 @@ static void debug_init() {
 hash_table_t function_hash_table;
 hash_table_t notfound_binding_table;
 
-static hash_table_t library_table;
+static hash_table_t library_table = EMPTY_HASH_TABLE;
 static library_t *library_list = NULL;
-unsigned int current_generation;
+unsigned int current_generation = 0;
 
 static hash_hashvalue_t link_map_hash(struct link_map *map) {
   hash_hashvalue_t hashval = (hash_hashvalue_t)((unsigned long)map);
@@ -72,8 +72,8 @@ static void setup_hash_tables() {
 }
 
 struct library_t *get_library(struct link_map *map) {
-  library_t *lib;
-  int result;
+  library_t *lib = NULL;
+  int result = 0;
   result =
       lookup_hashtable(&library_table, (hash_key_t)map, (hash_data_t *)&lib);
   if (result == -1) return NULL;

src/hash.c

@@ -34,8 +34,8 @@ typedef struct hash_entry_t hash_entry_t;
 
 int create_hashtable(hash_table_t *table, size_t initial_size,
                      hash_func_t hashfunc, hash_cmp_t keycmp) {
-  hash_entry_t *newtable;
-  int entries_per_page;
+  hash_entry_t *newtable = NULL;
+  int entries_per_page = 0;
 
   entries_per_page = gotcha_getpagesize() / sizeof(hash_entry_t);
   if (initial_size % entries_per_page)
@@ -86,9 +86,9 @@ static hash_entry_t *insert(hash_table_t *table, hash_key_t key,
 }
 
 int grow_hashtable(hash_table_t *table, size_t new_size) {
-  hash_table_t newtable;
-  hash_entry_t *result;
-  size_t i;
+  hash_table_t newtable = EMPTY_HASH_TABLE;
+  hash_entry_t *result = NULL;
+  size_t i = 0;
 
   newtable.table_size = new_size;
   newtable.entry_count = 0;
@@ -126,8 +126,8 @@ int destroy_hashtable(hash_table_t *table) {
 }
 
 static int lookup(hash_table_t *table, hash_key_t key, hash_entry_t **entry) {
-  size_t index, startindex;
-  hash_hashvalue_t hashval;
+  size_t index = 0, startindex = 0;
+  hash_hashvalue_t hashval = 0;
 
   hashval = table->hashfunc(key);
   index = hashval % table->table_size;
@@ -149,8 +149,8 @@ static int lookup(hash_table_t *table, hash_key_t key, hash_entry_t **entry) {
 }
 
 int lookup_hashtable(hash_table_t *table, hash_key_t key, hash_data_t *data) {
-  hash_entry_t *entry;
-  int result;
+  hash_entry_t *entry = NULL;
+  int result = 0;
 
   result = lookup(table, key, &entry);
   if (result == -1) return -1;
@@ -159,10 +159,10 @@ int lookup_hashtable(hash_table_t *table, hash_key_t key, hash_data_t *data) {
 }
 
 int addto_hashtable(hash_table_t *table, hash_key_t key, hash_data_t data) {
-  size_t newsize;
-  int result;
-  hash_hashvalue_t val;
-  hash_entry_t *entry;
+  size_t newsize = 0;
+  int result = 0;
+  hash_hashvalue_t val = 0;
+  hash_entry_t *entry = NULL;
 
   newsize = table->table_size;
   while (table->entry_count > newsize / 2) newsize *= 2;
@@ -179,8 +179,8 @@ int addto_hashtable(hash_table_t *table, hash_key_t key, hash_data_t data) {
 }
 
 int removefrom_hashtable(hash_table_t *table, hash_key_t key) {
-  hash_entry_t *entry;
-  int result;
+  hash_entry_t *entry = NULL;
+  int result = 0;
 
   result = lookup(table, key, &entry);
   if (result == -1) return -1;
@@ -202,8 +202,8 @@ int removefrom_hashtable(hash_table_t *table, hash_key_t key) {
 int foreach_hash_entry(hash_table_t *table, void *opaque,
                        int (*cb)(hash_key_t key, hash_data_t data,
                                  void *opaque)) {
-  int result;
-  struct hash_entry_t *i;
+  int result = 0;
+  struct hash_entry_t *i = NULL;
   for (i = table->head; i != NULL; i = i->next) {
     result = cb(i->key, i->data, opaque);
     if (result != 0) return result;  // GCOVR_EXCL_LINE
@@ -213,7 +213,7 @@ int foreach_hash_entry(hash_table_t *table, void *opaque,
 
 hash_hashvalue_t strhash(const char *str) {
   unsigned long hash = 5381;
-  int c;
+  int c = 0;
 
   while ((c = *str++)) hash = hash * 33 + c;
 

src/hash.h

@@ -35,6 +35,8 @@ typedef struct {
   struct hash_entry_t *table;
   struct hash_entry_t *head;
 } hash_table_t;
+#define EMPTY_HASH_TABLE \
+  {0, 0, NULL, NULL, NULL, NULL}
 
 int create_hashtable(hash_table_t *table, size_t initial_size, hash_func_t func,
                      hash_cmp_t keycmp);