1 #include <stdio.h> 2 #include <fcntl.h> 3 #include <util.h> 4 #include <unistd.h> 5 #include <sys/types.h> 6 #include <sys/stat.h> 7 #include <darwintest.h> 8 9 T_DECL(dev_zero, 10 "test reading from /dev/zero", 11 T_META_ASROOT(false)) 12 { 13 int dev = opendev("/dev/zero", O_RDONLY, 0, NULL); 14 char buffer[100]; 15 16 for (int i = 0; i < 100; i++) { 17 buffer[i] = 0xff; 18 } 19 20 int rd_sz = read(dev, buffer, sizeof(buffer)); 21 22 T_EXPECT_EQ(rd_sz, 100, "read from /dev/zero failed"); 23 24 for (int i = 0; i < 100; i++) { 25 if (buffer[i]) { 26 T_FAIL("Unexpected non-zero character read from /dev/zero"); 27 } 28 } 29 30 close(dev); 31 } 32 33 T_DECL(dev_zero_permissions, 34 "ensure /dev/zero's permissions can't be updated", 35 T_META_ASROOT(true)) 36 { 37 struct stat sb = {0}; 38 const char *dev = "/dev/zero"; 39 int ret = 0; 40 41 ret = stat(dev, &sb); 42 T_ASSERT_POSIX_SUCCESS(ret, "stat /dev/zero"); 43 T_ASSERT_TRUE(sb.st_mode & S_IWOTH, "/dev/zero world writable"); 44 45 ret = chmod(dev, 0664); 46 T_ASSERT_POSIX_FAILURE(ret, EPERM, "chmod /dev/zero should fail w/ EPERM"); 47 48 ret = stat(dev, &sb); 49 T_ASSERT_POSIX_SUCCESS(ret, "stat /dev/zero"); 50 T_ASSERT_TRUE(sb.st_mode & S_IWOTH, "/dev/zero still world writable"); 51 } 52