Ozgun just pointed out we can improve readability of this line by assigning the size of program string to a separate variable. This also goes along with the recommendation in chapter 31 of Code Complete to limit yourself to 1 statement per line.

```C
programLength = strlen(decompressor) + (4 * strlen(*filename)) + 4) * sizeof(char);
*program = palloc0(programLength);
```

Another comment on this line to prefer strnlen to strlen wherever possible.