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char buf[2048];
// simple fork and pipe read/write
void
pipe1()
{
int fds[2], pid;
int seq = 0, i, n, cc, total;
pipe(fds);
pid = fork();
if(pid == 0){
close(fds[0]);
for(n = 0; n < 5; n++){
for(i = 0; i < 1033; i++)
buf[i] = seq++;
if(write(fds[1], buf, 1033) != 1033){
puts("pipe1 oops 1\n");
exit(1);
}
}
exit(0);
} else {
close(fds[1]);
total = 0;
cc = 1;
while(1){
n = read(fds[0], buf, cc);
if(n < 1)
break;
for(i = 0; i < n; i++){
if((buf[i] & 0xff) != (seq++ & 0xff)){
puts("pipe1 oops 2\n");
return;
}
}
total += n;
cc = cc * 2;
if(cc > sizeof(buf))
cc = sizeof(buf);
}
if(total != 5 * 1033)
puts("pipe1 oops 3\n");
close(fds[0]);
}
puts("pipe1 ok\n");
}
// meant to be run w/ at most two CPUs
void
preempt()
{
int pid1, pid2, pid3;
int pfds[2];
pid1 = fork();
if(pid1 == 0)
while(1)
;
pid2 = fork();
if(pid2 == 0)
while(1)
;
pipe(pfds);
pid3 = fork();
if(pid3 == 0){
close(pfds[0]);
if(write(pfds[1], "x", 1) != 1)
puts("preempt write error");
close(pfds[1]);
while(1)
;
}
close(pfds[1]);
if(read(pfds[0], buf, sizeof(buf)) != 1){
puts("preempt read error");
return;
}
close(pfds[0]);
kill(pid1);
kill(pid2);
kill(pid3);
wait();
wait();
wait();
puts("preempt ok\n");
}
main()
{
puts("usertests starting\n");
pipe1();
//preempt();
while(1)
;
}
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