Simple `read()` wrapper for reading blocks without bothering with size checks.

bread.c

//  Requirements
//-----------------
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
//-----------------

// Reads a block of `count` bytes. If less than `count` bytes is available,
// fills the rest of `buf` with 0. Returns the number of bytes actually read.
// Note: Unlike read(), if the return value is less than `count`, it is
// guaranteed that the file has ended.
size_t bread(int fd, char *buf, size_t count)
{
    ssize_t temp = 0;
    size_t done = 0;
    while ((temp = read(fd, buf, count)))
    {
        if (temp < 0)
        {
            if (errno != EINTR) { exit(-errno); }
            continue;
        }
        count -= temp;
        done  += temp;
        buf   += temp;
    }
    memset(buf, 0, count);
    return done;
}