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//
// tests for copy-on-write fork() assignment.
//
#include "kernel/types.h"
#include "kernel/memlayout.h"
#include "user/user.h"
// allocate more than half of physical memory,
// then fork. this will fail in the default
// kernel, which does not support copy-on-write.
void
simpletest()
{
uint64 phys_size = PHYSTOP - KERNBASE;
int sz = (phys_size / 3) * 2;
printf("simple: ");
char *p = sbrk(sz);
if(p == (char*)0xffffffffffffffffL){
printf("sbrk(%d) failed\n", sz);
exit(-1);
}
for(char *q = p; q < p + sz; q += 4096){
*(int*)q = getpid();
}
int pid = fork();
if(pid < 0){
printf("fork() failed\n");
exit(-1);
}
if(pid == 0)
exit(0);
wait(0);
if(sbrk(-sz) == (char*)0xffffffffffffffffL){
printf("sbrk(-%d) failed\n", sz);
exit(-1);
}
printf("ok\n");
}
// three processes all write COW memory.
// this causes more than half of physical memory
// to be allocated, so it also checks whether
// copied pages are freed.
void
threetest()
{
uint64 phys_size = PHYSTOP - KERNBASE;
int sz = phys_size / 4;
int pid1, pid2;
printf("three: ");
char *p = sbrk(sz);
if(p == (char*)0xffffffffffffffffL){
printf("sbrk(%d) failed\n", sz);
exit(-1);
}
pid1 = fork();
if(pid1 < 0){
printf("fork failed\n");
exit(-1);
}
if(pid1 == 0){
pid2 = fork();
if(pid2 < 0){
printf("fork failed");
exit(-1);
}
if(pid2 == 0){
for(char *q = p; q < p + (sz/5)*4; q += 4096){
*(int*)q = getpid();
}
for(char *q = p; q < p + (sz/5)*4; q += 4096){
if(*(int*)q != getpid()){
printf("wrong content\n");
exit(-1);
}
}
exit(-1);
}
for(char *q = p; q < p + (sz/2); q += 4096){
*(int*)q = 9999;
}
exit(0);
}
for(char *q = p; q < p + sz; q += 4096){
*(int*)q = getpid();
}
wait(0);
sleep(1);
for(char *q = p; q < p + sz; q += 4096){
if(*(int*)q != getpid()){
printf("wrong content\n");
exit(-1);
}
}
if(sbrk(-sz) == (char*)0xffffffffffffffffL){
printf("sbrk(-%d) failed\n", sz);
exit(-1);
}
printf("ok\n");
}
char junk1[4096];
int fds[2];
char junk2[4096];
char buf[4096];
char junk3[4096];
// test whether copyout() simulates COW faults.
void
filetest()
{
printf("file: ");
buf[0] = 99;
for(int i = 0; i < 4; i++){
if(pipe(fds) != 0){
printf("pipe() failed\n");
exit(-1);
}
int pid = fork();
if(pid < 0){
printf("fork failed\n");
exit(-1);
}
if(pid == 0){
sleep(1);
if(read(fds[0], buf, sizeof(i)) != sizeof(i)){
printf("error: read failed\n");
exit(1);
}
sleep(1);
int j = *(int*)buf;
if(j != i){
printf("error: read the wrong value\n");
exit(1);
}
exit(0);
}
if(write(fds[1], &i, sizeof(i)) != sizeof(i)){
printf("error: write failed\n");
exit(-1);
}
}
int xstatus = 0;
for(int i = 0; i < 4; i++) {
wait(&xstatus);
if(xstatus != 0) {
exit(1);
}
}
if(buf[0] != 99){
printf("error: child overwrote parent\n");
exit(1);
}
printf("ok\n");
}
int
main(int argc, char *argv[])
{
simpletest();
// check that the first simpletest() freed the physical memory.
simpletest();
threetest();
threetest();
threetest();
filetest();
printf("ALL COW TESTS PASSED\n");
exit(0);
}
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