Creating a variable amount of linked lists for hashmap - c

Question

Here are the important parts of my code with unhelpful portions commented out:
#include <stdio.h>
#include <ctype.h>
#include <stdlib.h>
#include <string.h>
#include "hmap.h"
struct val_word{
char *final_word;
struct val_word* next;
};
int main (int argc, char **argv){
//Check if dictionary file is given
FILE *fp1;
char key [125];
char val [125];
char temp;
struct val_word *storage;
char c;
int i;
int j;
int l;
HMAP_PTR dictionary = hmap_create(0, 0.75);
fp1 = fopen(argv[1], "r");
do{
c = fscanf(fp1, "%s", key);
// Convert string to lowercase
strcpy(val, key);
//Alphabetically sort string
struct val_word* word_node = malloc(sizeof(struct val_word));
word_node->final_word = val;
word_node->next = NULL;
storage = hmap_get(dictionary, key);
if(storage == NULL){
hmap_set(dictionary, key, word_node);
}
else{
struct val_word *temp2 = storage;
while(temp2->next != NULL){
temp2 = temp2->next;
}
word_node->final_word = val;
word_node->next = NULL;
temp2->next = word_node;
hmap_set(dictionary, key, storage);
}
} while (c != EOF);
fclose(fp1);
while(storage->next != NULL){
printf("The list is %s\n", storage->final_word);
storage = storage->next;
}
return 0;
}
I am given a dictionary file of unknown length, as well as a hash table implementation file that I cannot touch. The hash table stores jumbled versions of words, with the key being the alphabetically sorted version of the word. For example:
Part of the dictionary contains: leloh, hello, elloh, holel
key would be: ehllo
val would be a linked list storing the aforementioned 4 words.
hmap_get gets the value at the given key, and hmap_set sets the value at the given key.
My code processes everything fine, until I try to print the list located at a key.
The list will be of the correct size, but only stores the LAST value that it took as input. So adding onto the example above, my list would be (in chronological order):
leloh
elloh -> elloh
holel -> holel -> holel
ehllo -> ehllo -> ehllo -> ehllo
For some reason it also stores the correctly alphabetized string as the last string, which I did not provide the hmap_set function. Very confused about that.
However, the list makes perfect sense. I only have one node, and it is inside of a for loop. I do not change the variable name and therefore the pointers all point to the same node, and the node changes the string it contains through every iteration of the loop.
So, I am wondering how I would fix this.
I can't dynamically name variables, I can't just create a dynamic array of linked lists because I feel like that would defeat the purpose of having the hash table.
I don't know what sort of data type I would use to store this.
Any help is appreciated, thank you!

Answer 1

Transferring comments into an answer — where the code is easier to read.
The problem is, I think, that you keep reading new values into val (copying from key), but you only have one variable.
You need to duplicate the strings before stashing them in your hash map. So, look up the strdup() function and make a copy of the string in key using strdup() instead of strcpy(). Assign the value returned from strdup() to word_node->final_word.
If you're not allowed to use strdup(), write your own variant:
char *dup_str(const char *str)
{
size_t len = strlen(str) + 1;
char *dup = malloc(len);
if (dup != 0)
memmove(dup, str, len);
return dup;
}