Write output of fts(3) to file

Question

I am developing a file fuzzer that mutates music files and feeds them to iTunes. I already developed code to mutate the music file, but I want to use more than one music file to increase code coverage. So I want to traverse my iTunes library and load the file paths into a buffer or into a file; either way will suffice. I have this code here that segfaults on the fprintf function.

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <errno.h>
#include <fts.h>

    int compare (const FTSENT**, const FTSENT**);

int main(void)
{   
FILE * musicPaths;
musicPaths = fopen("Users/NahNig/music_paths", "wb");
char *p1 = "/Users/NahNig/Music/iTunes/iTunes Media/Music";
char *p2 = NULL;
char *path[1];
path[0] = p1;
path[1] = p2;
FTS* file_system = NULL;
FTSENT* child =    NULL;
FTSENT* parent =   NULL;

file_system = fts_open(path, FTS_COMFOLLOW | FTS_NOCHDIR, &compare);

if (NULL != file_system)
{
    while( (parent = fts_read(file_system)) != NULL)
    {
        child = fts_children(file_system,0);

        if (errno != 0)
        {
            perror("fts_children");
        }

        while ((NULL != child)
            && (NULL != child->fts_link))
        {
            child = child->fts_link;
            fprintf(musicPaths, "%s%s\n", child->fts_path, child->fts_name);
            }
        }
        fts_close(file_system);
    }

    return 0;
}


int compare(const FTSENT** one, const FTSENT** two)
{
return (strcmp((*one)->fts_name, (*two)->fts_name));
}

I have tried using sscanf and fprintf to write child to a buffer and fwrite to try and write to a file; none of them have been working. What I found on Google also didn't help much, so any help would be greatly appreciated.

• fts_open()

Answer 1

You didn't test the return value from fopen(), which is NULL because you missed the first / from /Users/NahNig/music_paths. When you use the null pointer, the program crashes.