1 (* Memory info for virtual domains.
2 (C) Copyright 2008 Richard W.M. Jones, Red Hat Inc.
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 2 of the License, or
8 (at your option) any later version.
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program; if not, write to the Free Software
17 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
22 open Virt_mem_gettext.Gettext
27 virt-dmesg - dmesg command for virtual machines
30 virt-dmesg [-options] [domains]
33 virt-dmesg prints the kernel messages for virtual machines running
34 under libvirt. The output is similar to the ordinary dmesg command
35 run inside the virtual machine."
37 let _, images = Virt_mem.start usage
41 fun (name, arch, mem, lookup_ksym) ->
43 (* I don't know why but this symbol doesn't exist in 2.6.9
44 * even in kallsyms. Hence this won't work with that kernel.
45 * It's possible we can fall back to memory scanning. XXX
47 let log_buf = lookup_ksym "log_buf" in
48 let log_buf = follow_pointer mem log_buf in
49 let log_buf_len = lookup_ksym "log_buf_len" in
50 let log_buf_len = Int64.of_int32 (get_C_int mem log_buf_len) in
51 (* let log_start = lookup_ksym "log_start" in
52 let log_start = get_C_long mem log_start in *)
53 let log_end = lookup_ksym "log_end" in
54 let log_end = get_C_long mem log_end in
55 (* let con_start = lookup_ksym "con_start" in
56 let con_start = get_C_long mem con_start in *)
57 let logged_chars = lookup_ksym "logged_chars" in
58 let logged_chars = get_C_long mem logged_chars in
60 (* This is basically the same algorithm from printk.c:do_syslog
61 * type=3, translated into OCaml. Unlike the kernel version
62 * however we don't copy the buffer backwards.
65 let addr = log_buf +^ (idx &^ (log_buf_len -^ 1L)) in
66 Char.chr (get_byte mem addr)
69 let count = log_buf_len in
70 let count = if count > logged_chars then logged_chars else count in
71 let limit = log_end in
75 let j = limit-^1L-^i in
76 if j +^ log_buf_len >= log_end then (
77 let c = get_log_buf j in
86 eprintf (f_"%s: could not find kernel log buffer in kernel image\n")