movienfo | Tools to generate movie/tv nfo for kodi scrapers | Media Player library

Read carefully what strncpy does, e.g. at https://en.cppreference.com/w/c/string/byte/strncpy.

If, after copying the terminating null character from src, count is not reached, additional null characters are written to dest until the total of count characters have been written.

So if for instance title is 12 characters long, then 13 bytes will be allocated for newBlock->title, but strncpy(newBlock->title, title, 30) will write a full 30 bytes into that 13-byte array, thus overflowing it.

There is a separate bug if title is more than 30 characters long. Say it's 50. In this case you have allocated a full 51 bytes, but strncpy will only copy 30, and moreover:

If count is reached before the entire array src was copied, the resulting character array is not null-terminated.

As such, later attempts to call strcmp on the created string are likely to crash and/or give incorrect results.

Since you have allocated enough space to hold the entire string, there is no reason to cut it off at 30 characters. It is safe to just do strcpy(newBlock->title, title); which will fix both bugs and avoid unnecessary truncation to boot. If you really want to limit the title to 30 characters, then check its length when it is first input.

This recent answer has some good advice on using strncpy, i.e. "don't". Avoiding buffer overflows is important but strncpy isn't a very good solution.

One more bug is that you've forgotten to fill in newBlock->rating.