diff options
Diffstat (limited to 'user')
| -rw-r--r-- | user/cow.c | 196 | ||||
| -rw-r--r-- | user/usertests.c | 13 |
2 files changed, 206 insertions, 3 deletions
diff --git a/user/cow.c b/user/cow.c new file mode 100644 index 0000000..45efc98 --- /dev/null +++ b/user/cow.c @@ -0,0 +1,196 @@ +// +// 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(1, "simple: "); + + char *p = sbrk(sz); + if(p == (char*)0xffffffffffffffffL){ + printf(1, "sbrk(%d) failed\n", sz); + exit(); + } + + for(char *q = p; q < p + sz; q += 4096){ + *(int*)q = getpid(); + } + + int pid = fork(); + if(pid < 0){ + printf(1, "fork() failed\n"); + exit(); + } + + if(pid == 0) + exit(); + + wait(); + + if(sbrk(-sz) == (char*)0xffffffffffffffffL){ + printf(1, "sbrk(-%d) failed\n", sz); + exit(); + } + + printf(1, "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(1, "three: "); + + char *p = sbrk(sz); + if(p == (char*)0xffffffffffffffffL){ + printf(1, "sbrk(%d) failed\n", sz); + exit(); + } + + pid1 = fork(); + if(pid1 < 0){ + printf(1, "fork failed\n"); + exit(); + } + if(pid1 == 0){ + pid2 = fork(); + if(pid2 < 0){ + printf(1, "fork failed"); + exit(); + } + 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(1, "wrong content\n"); + exit(); + } + } + exit(); + } + for(char *q = p; q < p + (sz/2); q += 4096){ + *(int*)q = 9999; + } + exit(); + } + + for(char *q = p; q < p + sz; q += 4096){ + *(int*)q = getpid(); + } + + wait(); + + sleep(1); + + for(char *q = p; q < p + sz; q += 4096){ + if(*(int*)q != getpid()){ + printf(1, "wrong content\n"); + exit(); + } + } + + if(sbrk(-sz) == (char*)0xffffffffffffffffL){ + printf(1, "sbrk(-%d) failed\n", sz); + exit(); + } + + printf(1, "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() +{ + int parent = getpid(); + + printf(1, "file test: "); + + buf[0] = 99; + + for(int i = 0; i < 4; i++){ + if(pipe(fds) != 0){ + printf(1, "pipe() failed\n"); + exit(); + } + int pid = fork(); + if(pid < 0){ + printf(1, "fork failed\n"); + exit(); + } + if(pid == 0){ + sleep(1); + if(read(fds[0], buf, sizeof(i)) != sizeof(i)){ + printf(1, "read failed\n"); + kill(parent); + exit(); + } + sleep(1); + int j = *(int*)buf; + if(j != i){ + printf(1, "read the wrong value\n"); + kill(parent); + exit(); + } + exit(); + } + if(write(fds[1], &i, sizeof(i)) != sizeof(i)){ + printf(1, "write failed\n"); + exit(); + } + } + + for(int i = 0; i < 4; i++) + wait(); + + if(buf[0] != 99){ + printf(1, "child overwrote parent\n"); + exit(); + } + + printf(1, "ok\n"); +} + +int +main(int argc, char *argv[]) +{ + simpletest(); + + // check that the first simpletest() freed the physical memory. + simpletest(); + + threetest(); + threetest(); + threetest(); + + filetest(); + + printf(1, "ALL COW TESTS PASSED\n"); + + exit(); +} diff --git a/user/usertests.c b/user/usertests.c index beca8f9..ef70bfb 100644 --- a/user/usertests.c +++ b/user/usertests.c @@ -1438,6 +1438,13 @@ sbrktest(void) printf(stdout, "sbrk test\n"); oldbrk = sbrk(0); + // does sbrk() return the expected failure value? + a = sbrk(1024*1024*1024); + if(a != (char*)0xffffffffffffffffL){ + printf(stdout, "sbrk(<toomuch>) returned %p\n", a); + exit(); + } + // can one sbrk() less than a page? a = sbrk(0); for(i = 0; i < 5000; i++){ @@ -1466,7 +1473,7 @@ sbrktest(void) // can one grow address space to something big? a = sbrk(0); - amt = (BIG) - (uint64)a; + amt = BIG - (uint64)a; p = sbrk(amt); if (p != a) { printf(stdout, "sbrk test failed to grow big address space; enough phys mem?\n"); @@ -1478,7 +1485,7 @@ sbrktest(void) // can one de-allocate? a = sbrk(0); c = sbrk(-4096); - if(c == (char*)0xffffffff){ + if(c == (char*)0xffffffffffffffffL){ printf(stdout, "sbrk could not deallocate\n"); exit(); } @@ -1551,7 +1558,7 @@ sbrktest(void) kill(pids[i]); wait(); } - if(c == (char*)0xffffffff){ + if(c == (char*)0xffffffffffffffffL){ printf(stdout, "failed sbrk leaked memory\n"); exit(); } |