Question

我知道有人问过类似的问题。但是我仍然不能解决我的问题。因此，如果您能帮助我了解我在做什么错，我将非常感谢。我的程序基本上从文件中读取单词，并将它们作为键/值对放入哈希表中。然后，它将另一个文件中的单词与HT中的单词进行比较，如果找到它，则返回值...

    char *str_dup(const char *s) {
      if (s == NULL) { // Optional test, s should point to a string
        return NULL;
      }
      size_t siz = strlen(s) + 1;
      char *y = malloc(sizeof(siz));
      if (y != NULL) {
        memcpy(y, s, siz);
      }
      return y;
    }

    int ht_put(HashTable *hashtable, const char *key, const char 
    *value){
    List *node;

    if (hashtable == NULL) {
            return 2;
    }

    node = malloc(sizeof(List));
    if (node == NULL) {
            return 2;
    }
    node->key = str_dup(key);
    node->value = str_dup(value);

    node_handler(hashtable, node);

    return 0;
    }

    HashTable *dict;
    dict = ht_create(numKeys);
    if(dict == NULL){
        return 2;
    }

    char *val;
    int cnt = 0;
    while(fgets(buffer,1000000000,wb)) {
        // Eliminate UNIX/DOS line terminator
        val=strrchr(buffer,'\n');
        if (val) *val=0;
        val=strrchr(buffer,'\r');
        if (val) *val=0;

        //Find first occurrence of the separator ':'
        val=strchr(buffer,':');
        if (val) {
            // Truncates buffer string to first word
            // and (++) points second word
            *val++=0;
        }

        if (cnt<1000000000) {
            if (val!=NULL) {
                    if(ht_get(dict,buffer) == NULL){
                       ht_put(dict,buffer,val);
                    }
                    else {
                            ht_free(dict);
                            fclose(wb);
                            free(buffer);
                            fprintf(stderr,"Zwei Zeilen beschreiben 
         dasselbe deutsche Wort.\n");
                            exit(2);
                            return 2;
                    }
            }
            cnt++;
        } 
    }
    fclose(wb);
    free(buffer);

这是valgrind显示的内容：

    ==478519== Invalid write of size 2
    ==478519==    at 0x4C325E3: memcpy@GLIBC_2.2.5 (in 
    /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
    ==478519==    by 0x401701: strdup (loesung.c:62)
    ==478519==    by 0x401701: ht_put (loesung.c:285)
    ==478519==    by 0x400FA2: main (loesung.c:389)
    ==478519==  Address 0x51fc958 is 0 bytes after a block of size 
    8 alloc'd
    ==478519==    at 0x4C2E01F: malloc (in 
    /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
    ==478519==    by 0x4016EA: strdup (loesung.c:60)
    ==478519==    by 0x4016EA: ht_put (loesung.c:285)
    ==478519==    by 0x400FA2: main (loesung.c:389)

Answer 1

执行此操作时：

char *y = malloc(sizeof(siz));

sizeof（size）等于变量siz的字节数，即size_t的字节数。这真的是您想要的，还是您想要做的：

char *y = malloc(siz);

Valgrind“大小为1的无效写入/读取”错误memcpy

1 个答案: