[SOLVED] Getting hash of a binary file C

Getting hash of a binary file C

I want to get hash of a binary file whose name I have. I have tried the following, but then realized that SHA1() is returning hash value for the string ( name of the file). But I want to run it on the file itself. Any pointers on how to do that would be great.

char *fileName = "/bin/ls"
unsigned char hash[SHA_DIGEST_LENGTH];
SHA1((unsigned char *)fileName, strlen(fileName),hash);

Solution

Thanks to everyone's comments I solved the problem. I am posting the code here, so others might find it beneficial.

void getFileHash(char *fileName){

    unsigned char result[2*SHA_DIGEST_LENGTH];
    unsigned char hash[SHA_DIGEST_LENGTH];
    int i;
    FILE *f = fopen(fileName,"rb");
    SHA_CTX mdContent;
    int bytes;
    unsigned char data[1024];

    if(f == NULL){
        printf("%s couldn't open file\n",fileName);
        exit(1);
    }

    SHA1_Init(&mdContent);
    while((bytes = fread(data, 1, 1024, f)) != 0){

        SHA1_Update(&mdContent, data, bytes);
    }
    
    SHA1_Final(hash,&mdContent);

    for(i=0;i<SHA_DIGEST_LENGTH;i++){
        printf("%02x",hash[i]);
    }
    printf("\n");
    /** if you want to see the plain text of the hash */
    for(i=0; i < SHA_DIGEST_LENGTH;i++){
        sprintf((char *)&(result[i*2]), "%02x",hash[i]);
    }

    printf("%s\n",result);

    fclose(f);
}