1 00:00:00,001 --> 00:00:05,005 (upbeat music) 2 00:00:05,005 --> 00:00:06,003 - [Instructor] So we get 3 00:00:06,003 --> 00:00:10,008 to use some loadable kernel commands. 4 00:00:10,008 --> 00:00:13,009 All right, so we're supposed to find out 5 00:00:13,009 --> 00:00:15,009 how many are dynamically loaded. 6 00:00:15,009 --> 00:00:18,004 So the lsmod command shows us those. 7 00:00:18,004 --> 00:00:22,005 So if we do lsmod, pipe it into WC minus L, 8 00:00:22,005 --> 00:00:24,000 we get 64. 9 00:00:24,000 --> 00:00:27,009 And just a reminder, there is one line ahead of there. 10 00:00:27,009 --> 00:00:31,004 So it looks like we have 63 modules loaded in here 11 00:00:31,004 --> 00:00:36,006 and we had over 800 modules installed on the system. 12 00:00:36,006 --> 00:00:39,009 What about the last module loaded? 13 00:00:39,009 --> 00:00:42,000 Well, that was the top there, 14 00:00:42,000 --> 00:00:44,003 but the question is, what was the first one? 15 00:00:44,003 --> 00:00:49,005 So the first one would be, pipe this into tail. 16 00:00:49,005 --> 00:00:54,000 And it looks like autofs4 was the first one loaded. 17 00:00:54,000 --> 00:00:57,002 As a little aside, it's possible 18 00:00:57,002 --> 00:00:59,009 that you have a module loaded in your kernel 19 00:00:59,009 --> 00:01:03,007 that does not exist in your file system 20 00:01:03,007 --> 00:01:08,007 because when your Linux system boots, it typically starts 21 00:01:08,007 --> 00:01:13,007 with an initial file system in RAM 22 00:01:13,007 --> 00:01:17,006 and that can have modules in it that don't exist 23 00:01:17,006 --> 00:01:20,008 in your disk file system. 24 00:01:20,008 --> 00:01:25,009 So in case you find that mystery, there's the answer for it. 25 00:01:25,009 --> 00:01:26,008 All right, now we wanted 26 00:01:26,008 --> 00:01:32,002 to look at a module called msdos. 27 00:01:32,002 --> 00:01:34,004 So let's see if that's loaded. 28 00:01:34,004 --> 00:01:38,002 Lsmod, grep msdos. 29 00:01:38,002 --> 00:01:41,002 Nope, not loaded on my system, so I'm going to load it. 30 00:01:41,002 --> 00:01:51,006 So that is a standard module, so mod probe for loading that. 31 00:01:51,006 --> 00:01:56,004 It's loaded, got a size, no dependencies, 32 00:01:56,004 --> 00:01:59,004 and the use count is zero. 33 00:01:59,004 --> 00:02:05,002 Okay, so we can remove it. 34 00:02:05,002 --> 00:02:08,003 No complaints there. 35 00:02:08,003 --> 00:02:11,001 Looks like it's gone, all looks good. 36 00:02:11,001 --> 00:02:14,009 Then we wanted to look at some module information 37 00:02:14,009 --> 00:02:16,009 for the Sun RPC module. 38 00:02:16,009 --> 00:02:21,001 So the command for that is modinfo, 39 00:02:21,001 --> 00:02:22,006 and I'm going to pipe that into more 40 00:02:22,006 --> 00:02:25,004 because it produces quite a bit of stuff. 41 00:02:25,004 --> 00:02:26,006 We start at the top there. 42 00:02:26,006 --> 00:02:30,009 The second line says the license is GPL. 43 00:02:30,009 --> 00:02:34,004 Okay and we need to look for version magic. 44 00:02:34,004 --> 00:02:39,004 And if we go down a number of lines, I see vermagic 45 00:02:39,004 --> 00:02:41,007 and I see the kernel version string. 46 00:02:41,007 --> 00:02:44,004 That's the kernel I'm booted into right now. 47 00:02:44,004 --> 00:02:47,001 And then some kernel configuration options 48 00:02:47,001 --> 00:02:48,007 that have to match. 49 00:02:48,007 --> 00:02:52,003 So if I tried to load this module into a kernel, 50 00:02:52,003 --> 00:02:54,001 that same kernel version, 51 00:02:54,001 --> 00:02:57,008 but was not SMP, then it wouldn't work. 52 00:02:57,008 --> 00:03:01,009 And then if we scroll down some more, 53 00:03:01,009 --> 00:03:04,009 at the bottom we see some parms. 54 00:03:04,009 --> 00:03:10,005 And if I count those, I count 2, 4, 6, 8, 9, 10, I count 10. 55 00:03:10,005 --> 00:03:15,004 So it looks like the Sun RPC module has 10 parameters 56 00:03:15,004 --> 00:03:20,001 that could be set when we load the module. 57 00:03:20,001 --> 00:03:23,007 And incidentally, potentially those parameters could show up 58 00:03:23,007 --> 00:03:28,000 underneath the sysfile system and we could look at 'em 59 00:03:28,000 --> 00:03:31,001 or potentially even change 'em later on. 60 00:03:31,001 --> 00:03:32,004 I haven't looked for this module, 61 00:03:32,004 --> 00:03:35,009 but some modules support that too. 62 00:03:35,009 --> 00:03:37,000 All right, good luck.