The strange behavior of 'read' system function

The programm I tried writing should have been able to read a string of a length not longer than 8 characters and check if such string were present in the file. I decided to use 'read' system function for it, but I've come up with a strange behavior of this function. As it's written in manual, it must return 0 when the end of file is reached, but in my case when there were no more characters to read it still read a '\n' and returned 1 (number of bytes read) (I've checked the ASCII code of the read character and it's actually 10 which is of '\n'). So considering this fact I changed my code and it worked, but I still can't understand why does it behave in this way. Here is the code of my function:

int is_present(int fd, char *string)
{
    int i;
    char ch, buf[9];

    if (!read(fd, &ch, 1)) //file is empty
        return 0;

    while (1) {
        i = 0;
        while (ch != '\n') {
            buf[i++] = ch;
            read(fd, &ch, 1);
        }
        buf[i] = '\0';
        if (!strncmp(string, buf, strlen(buf))) {
            close(fd);
            return 1;
        }
        if(!read(fd, &ch, 1)) //EOF reached
            break;
    }
    close(fd);
    return 0;
}