C code - segmentation fault - c

Question

I'm trying to compile my c code, but I always get Segmentation fault after I execute my program. Here is part of my code:
LINE_LENGTH=300
struct clip {
int views;
char *user;
char *id;
char *title;
char *duration;
struct clip *next;
} *head;
my main function, where argv[1] is my csv file
int main(int argc, char **argv) {
int n;
head = build_a_lst(*(argv+1));
return 0;}
The rest of my code
struct clip *build_a_lst(char *fn) {
FILE *fp;
struct clip *hp;
char *fields[5];
char line[LINE_LENGTH];
int cnt=0,i;
hp=NULL;
fp=fopen(fn,"r");
if(fp=NULL)
exit(EXIT_FAILURE);
while(fgets(line,LINE_LENGTH,fp)!=NULL){
split_line(fields,line);//fields has five values stored
hp=append(hp,fields);
for(i=0;i<5;i++){
free(fields[i]);
fields[i]=NULL;
}
}
return hp;
}
void split_line(char **fields,char *line) {
int i=0;
char *token, *delim;
delim = ",\n";
token=strtok(line,delim);//ok line
for(;token!=NULL;i++){
fields[i]=malloc(strlen(token)+1);
strcpy(fields[i],token);
token=strtok(NULL,delim);
}
}
struct clip *append(struct clip *hp,char **five) {
struct clip *cp,*tp;
tp=malloc(sizeof(struct clip));
tp->views=atoi(five[1]);
tp->user=malloc(strlen(five[0]+1));
tp->duration=malloc(strlen(five[2]+1));
tp->id=malloc(strlen(five[3]+1));
tp->title=malloc(strlen(five[4]+1));
strcpy(tp->user,five[0]);
strcpy(tp->duration,five[2]);
strcpy(tp->id,five[3]);
strcpy(tp->title,five[4]);
cp=hp;
while(cp!=NULL)
cp=cp->next;
cp->next=tp;
hp=cp;
return hp;
}
According to some articles segmentation fault is caused by trying to read or write an illegal memory location. And since I am allocating memory in different parts of my code, the problem should be there. Can someone please help me with this. Thank you in advance.

Answer 1

There are some problems with your code:
if(fp=NULL) should be if(fp == NULL)
char *fields[5]; should be char *fields[5] = {NULL};
for(;token!=NULL;i++){ should be for(; token != NULL && i < 5; i++){
These:
tp->user=malloc(strlen(five[0]+1));
tp->duration=malloc(strlen(five[2]+1));
tp->id=malloc(strlen(five[3]+1));
tp->title=malloc(strlen(five[4]+1));
should be
tp -> user = malloc(strlen(five[0]) + 1);
tp -> duration = malloc(strlen(five[2]) + 1);
tp -> id = malloc(strlen(five[3]) + 1);
tp -> title = malloc(strlen(five[4]) + 1);
You don't free several of the malloced memory.