C 段错误 malloc.c : No such file or directory

Question

这是我的代码:

// Implements a dictionary's functionality

#include <stdbool.h>
#include <stdio.h>
#include <cs50.h>
#include <ctype.h>
#include <string.h>
#include <strings.h>
#include <stdlib.h>

#include "dictionary.h"

// Maximum length for a word
#define LENGTH 45

//define struct node
typedef struct node
{
    char word[LENGTH + 1];
    struct node *next;
}
node;

//hash function
unsigned int hash(const char word[LENGTH + 1])
{
    int x = atoi(&word[0]);
    int y;
    if(isupper(word[0]))
    {
        y = (x + 13) % 26;
    }
    if(islower(word[0]))
    {
        y = (x + 7) % 26;
    }
    if(isalpha(word[0]) == 0)
    {
        return 0;
    }
    return y;
}

//make a hash table of linked lists
node* hash_table[26];

// Returns true if word is in dictionary else false
bool check(const char *word)
{
    node *head = hash_table[hash(word)];
    node *cursor = head;
    while (cursor != NULL)
    {
        if (strcasecmp(word, cursor->word) == 0)
        {
            return true;
        }
        cursor = cursor->next;
    }
    return false;
}

// Loads dictionary into memory, returning true if successful else false
bool load(const char *dictionary)
{
    char word[LENGTH + 1];
    FILE *dictionary_file = fopen(dictionary, "r");
    if (dictionary_file == NULL)
    {
        unload ();
        return false;
    }

    while (fscanf(dictionary_file, "%s", word) != EOF)
    {
        //allocate memory for node
        node *new_node = malloc(sizeof(node));
        if (new_node == NULL)
        {
            unload();
            return false;
        }

        //insert node into linked list
        int index = hash(word);
        node *head = hash_table[hash(word)];

        //place word in node
        strcpy(new_node->word, word);

        //connect nodes
        new_node->next = head;
        hash_table[index] = new_node;
        }
    fclose(dictionary_file);
    return true;
}

// Returns number of words in dictionary if loaded else 0 if not yet loaded
unsigned int size(void)
{
    int sum = 0;
    if (&load)
    {
        char word[LENGTH + 1];
        const char *dictionary;
        FILE *dictionary_file = fopen(dictionary, "r");
        while (fscanf(dictionary_file, "%s", word) != EOF)
        {
            sum++;
        }
    }
    return sum;
}

// Unloads dictionary from memory, returning true if successful else false
bool unload(void)
{
    char word[LENGTH + 1];
    node *head = hash_table[hash(word)];
    node *cursor = head;

    while (cursor != NULL)
    {
        node *temp = cursor;
        cursor = cursor->next;
        free(temp);
    }

    if (cursor == NULL)
    {
        return true;
    }
    else
    {
       return false;
    }
}

当我通过 GDB 运行它时，我收到此消息，指示段错误:

Program received signal SIGSEGV, Segmentation fault.
_int_malloc (av=0x7ffff728d760 <main_arena>, bytes=56) at malloc.c:3777
3777    malloc.c: No such file or directory.

这是当我输入“where”时 GDB 的响应:

#0  _int_malloc (av=0x7ffff728d760 <main_arena>, bytes=56) at malloc.c:3777
#1  0x00007ffff6f4dae0 in __GI___libc_malloc (bytes=56) at malloc.c:2893
#2  0x0000000000422abf in load (dictionary=0x382e332d6e696168 <error: Cannot access memory at address 0x382e332d6e696168>)
    at dictionary.c:66
#3  0x722d72656c69706d in ?? ()
#4  0x61732f62696c2f74 in ?? ()
#5  0x5f72657a6974696e in ?? ()
#6  0x732f6e6f6d6d6f63 in ?? ()
#7  0x72657a6974696e61 in ?? ()
#8  0x632e7367616c665f in ?? ()
#9  0x6165720000000063 in ?? ()
#10 0x0063632e31720064 in ?? ()
#11 0x2828000000000000 in ?? ()
#12 0x5f76625f706d7421 in ?? ()
#13 0x287469427465672e in ?? ()
#14 0x6c00292929786469 in ?? ()
#15 0x6c6f6f742d6d766c in ?? ()

有人知道为什么会出现段错误吗？当我通过valgrind运行程序时，系统提示没有内存泄漏。有人知道如何解决这个问题吗？

Answer 1

关于:

const char *dictionary;
FILE *dictionary_file = fopen(dictionary, "r");

(可能是seg错误的原因)

指针dictionary在传递给fopen()之前未初始化

因此代码尝试从内存中的某个“随机”位置读取一些“随机”字节数(直到遇到 NUL 字节)，以尝试获取要打开的文件的名称。

OT:调用 C 库函数(例如 fopen())时，请始终在调用后检查是否有任何错误。

编译时，始终启用警告，然后修复这些警告。 (对于gcc，至少使用:-Wall -Wextra -Wconversion -pedantic -std=gnu11)