Hm. What's happening is that you aren't finishing your write: after sending data to the child process, you have to tell it you're done writing, either by closing pipe1_ends[1] or calling shutdown(2)
on it. You should also call write/read in a loop, since it's quite likely in the general case that read at least won't give you all the results in one go. Obviously the full code checks all return values, doesn't it?
One final thing: Your printf is badly broken. It can only accept null-terminated strings, and the result returned by read
will not be null-terminated (it's a buffer-with-length, the other common way of knowing where the end is). You want:
int n = read(pipe2_ends[0], buffer, 99);
if (n < 0) { perror("read"); exit(1); }
buffer[n] = 0;
printf("%s",buffer);