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authorMole Shang <[email protected]>2024-02-14 20:46:23 +0800
committerMole Shang <[email protected]>2024-02-14 20:46:23 +0800
commitf98eeb30507040dc916b2a337818830954ee1d4a (patch)
treea741cb0bbd6be96d8084e72b4af895ac093a2b48 /user/cowtest.c
parent0de5ac779602f562a038e5ad27163d85bc71638b (diff)
parent904885a96efd1dd0221585f67477f5a39bcce7f7 (diff)
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Merge branch 'net' into lock
Conflicts: .gitignore Makefile conf/lab.mk kernel/defs.h user/user.h
Diffstat (limited to 'user/cowtest.c')
-rw-r--r--user/cowtest.c197
1 files changed, 197 insertions, 0 deletions
diff --git a/user/cowtest.c b/user/cowtest.c
new file mode 100644
index 0000000..29b918f
--- /dev/null
+++ b/user/cowtest.c
@@ -0,0 +1,197 @@
+//
+// 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);
+}