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journalctl: Add support for showing messages from a previous boot 

Hi,

I redid the boot ID look up to use enumerate_unique.

This is quite fast if the cache is warm but painfully slow if
it isn't. It has a slight chance of returning the wrong order if
realtime clock jumps around.

This one has to do n searches for every boot ID there is plus
a sort, so it depends heavily on cache hotness. This is in contrast
to the other way of look-up through filtering by a MESSAGE_ID,
which only needs about 1 seek + whatever amount of relative IDs
you want to walk.

I also have a linked-list + (in-place) mergesort version of this
patch, which has pretty much the same runtime. But since this one
is using libc sorting and armortized allocation, I prefer this
one.

To summarize: The MESSAGE_ID way is a *lot* faster but can be
incomplete due to rotation, while the enumerate+sort will find
every boot ID out there but will be painfully slow for large
journals and cold caches.

You choose :P

Jan
This commit is contained in:
Jan Janssen 2013-06-28 17:26:30 +02:00 committed by Lennart Poettering
parent 18d4e7c26e
commit a331b5e6d4
4 changed files with 234 additions and 26 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
TODO
View File

@ -356,7 +356,6 @@ Features:
- journal-send.c, log.c: when the log socket is clogged, and we drop, count this and write a message about this when it gets unclogged again.
- journal: find a way to allow dropping history early, based on priority, other rules
- journal: When used on NFS, check payload hashes
- Introduce journalctl -b <nr> to show journal messages of a previous boot
- journald: check whether it is OK if the client can still modify delivered journal entries
- journal live copy, based on libneon (client) and libmicrohttpd (server)
- journald: add kernel cmdline option to disable ratelimiting for debug purposes

52
man/journalctl.xml
View File

@ -327,23 +327,51 @@
</varlistentry>
<varlistentry>
<term><option>-b</option></term>
<term><option>--this-boot</option></term>
<term><option>-b <optional><replaceable>ID</replaceable></optional></option></term>
<term><option>--boot=<optional><replaceable>ID</replaceable></optional></option></term>
<listitem><para>Show data only from
current boot. This will add a match
for <literal>_BOOT_ID=</literal> for
the current boot ID of the
kernel.</para></listitem>
<listitem><para>Show messages from the specified
boot <replaceable>ID</replaceable> or from
current boot if no <replaceable>ID</replaceable>
is given. This will add a match for
<literal>_BOOT_ID=</literal>.</para>
<para>The argument is a 128 bit ID given in
short or UUID form and optionally followed by
<literal>:n</literal> which identifies the nth
boot relative to the boot ID given to the left
of <literal>:</literal>. Supplying a negative
value for n will look for a past boot and a
positive value for a future boot. The boot IDs
are searched for in chronological order. If no
number is provided after <literal>:</literal>,
<literal>-1</literal> is assumed. A value of 0
is valid and equivalent to omitting
<literal>:0</literal>.</para>
<para>Alternatively, the argument may constist
only of <literal>:n</literal>. In this case, a
positive value will look up the nth boot
starting from the beginning of the jouranl, a
negative value will look up a previous boot
relative to the current boot. <literal>:0</literal>
will look for the current boot ID. Thus,
<literal>:1</literal> is the first boot found in
the journal, <literal>:2</literal> the second
and so on; while <literal>:-1</literal> is the
previous boot, <literal>:-2</literal> the boot
before that and so on. Omitting a value after
<literal>:</literal> will look for the previous
boot.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>-k</option></term>
<term><option>--dmesg</option></term>
<listitem><para>Show kernel messages from
current boot. This implies <option>-b</option>
and adds the match <literal>_TRANSPORT=kernel</literal>.
<listitem><para>Show only kernel messages. This
implies <option>-b</option> and adds the match
<literal>_TRANSPORT=kernel</literal>.
</para></listitem>
</varlistentry>
@ -721,6 +749,10 @@
<programlisting>journalctl /dev/sda</programlisting>
<para>Show all kernel logs from last boot:</para>
<programlisting>journalctl -k -b :</programlisting>
</refsect1>
<refsect1>

11
shell-completion/bash/journalctl
View File

@ -37,19 +37,22 @@ __journal_fields=(MESSAGE{,_ID} PRIORITY CODE_{FILE,LINE,FUNC}
_journalctl() {
local field_vals= cur=${COMP_WORDS[COMP_CWORD]} prev=${COMP_WORDS[COMP_CWORD-1]}
local -A OPTS=(
[STANDALONE]='-a --all --full
--system --user
-b --this-boot --disk-usage -f --follow --header
[STANDALONE]='-a --all --full --system --user
--disk-usage -f --follow --header
-h --help -l --local --new-id128 -m --merge --no-pager
--no-tail -q --quiet --setup-keys --this-boot --verify
--version --list-catalog --update-catalog'
[ARG]='-D --directory -F --field -o --output -u --unit --user-unit'
[ARG]='-b --boot --this-boot -D --directory -F --field
-o --output -u --unit --user-unit'
[ARGUNKNOWN]='-c --cursor --interval -n --lines -p --priority --since --until
--verify-key'
)
if __contains_word "$prev" ${OPTS[ARG]} ${OPTS[ARGUNKNOWN]}; then
case $prev in
--boot|--this-boot|-b)
comps=$(journalctl -F '_BOOT_ID' 2>/dev/null)
;;
--directory|-D)
comps=$(compgen -d -- "$cur")
compopt -o filenames

196
src/journal/journalctl.c
View File

@ -70,7 +70,8 @@ static int arg_lines = -1;
static bool arg_no_tail = false;
static bool arg_quiet = false;
static bool arg_merge = false;
static bool arg_this_boot = false;
static bool arg_boot_id = false;
static char *arg_boot_id_descriptor = NULL;
static bool arg_dmesg = false;
static const char *arg_cursor = NULL;
static const char *arg_directory = NULL;
@ -103,6 +104,11 @@ static enum {
ACTION_UPDATE_CATALOG
} arg_action = ACTION_SHOW;
typedef struct boot_id_t {
sd_id128_t id;
uint64_t timestamp;
} boot_id_t;
static int help(void) {
printf("%s [OPTIONS...] [MATCHES...]\n\n"
@ -113,8 +119,8 @@ static int help(void) {
" --since=DATE Start showing entries newer or of the specified date\n"
" --until=DATE Stop showing entries older or of the specified date\n"
" -c --cursor=CURSOR Start showing entries from specified cursor\n"
" -b --this-boot Show data only from current boot\n"
" -k --dmesg Show kmsg log from current boot\n"
" -b --boot[=ID] Show data only from ID or current boot if unspecified\n"
" -k --dmesg Show kernel message log from current boot\n"
" -u --unit=UNIT Show data only from the specified unit\n"
" --user-unit=UNIT Show data only from the specified user session unit\n"
" -p --priority=RANGE Show only messages within the specified priority range\n"
@ -199,7 +205,8 @@ static int parse_argv(int argc, char *argv[]) {
{ "new-id128", no_argument, NULL, ARG_NEW_ID128 },
{ "quiet", no_argument, NULL, 'q' },
{ "merge", no_argument, NULL, 'm' },
{ "this-boot", no_argument, NULL, 'b' },
{ "boot", optional_argument, NULL, 'b' },
{ "this-boot", optional_argument, NULL, 'b' }, /* deprecated */
{ "dmesg", no_argument, NULL, 'k' },
{ "system", no_argument, NULL, ARG_SYSTEM },
{ "user", no_argument, NULL, ARG_USER },
@ -232,7 +239,7 @@ static int parse_argv(int argc, char *argv[]) {
assert(argc >= 0);
assert(argv);
while ((c = getopt_long(argc, argv, "hefo:aln::qmbkD:p:c:u:F:xr", options, NULL)) >= 0) {
while ((c = getopt_long(argc, argv, "hefo:aln::qmb::kD:p:c:u:F:xr", options, NULL)) >= 0) {
switch (c) {
@ -331,11 +338,17 @@ static int parse_argv(int argc, char *argv[]) {
break;
case 'b':
arg_this_boot = true;
if (optarg)
arg_boot_id_descriptor = optarg;
else if (optind < argc && argv[optind][0] != '-') {
arg_boot_id_descriptor = argv[optind];
optind++;
}
arg_boot_id = true;
break;
case 'k':
arg_this_boot = arg_dmesg = true;
arg_boot_id = arg_dmesg = true;
break;
case ARG_SYSTEM:
@ -630,11 +643,170 @@ static int add_matches(sd_journal *j, char **args) {
return 0;
}
static int add_this_boot(sd_journal *j) {
if (!arg_this_boot)
static int boot_id_cmp(const void *a, const void *b) {
uint64_t _a, _b;
_a = ((const boot_id_t *)a)->timestamp;
_b = ((const boot_id_t *)b)->timestamp;
return _a < _b ? -1 : (_a > _b ? 1 : 0);
}
static int get_relative_boot_id(sd_journal *j, sd_id128_t *boot_id, int relative) {
int r;
const void *data;
unsigned int id_count = 0;
size_t length, allocated = 0;
boot_id_t ref_boot_id, *id;
_cleanup_free_ boot_id_t *all_ids = NULL;
bool find_first_boot = false, ref_boot_found = false;
assert(j);
assert(boot_id);
if (relative == 0)
return 0;
return add_match_this_boot(j);
if (sd_id128_equal(*boot_id, SD_ID128_NULL) && relative > 0) {
find_first_boot = true;
relative--;
}
r = sd_journal_query_unique(j, "_BOOT_ID");
if (r < 0)
return r;
SD_JOURNAL_FOREACH_UNIQUE(j, data, length) {
if (length < strlen("_BOOT_ID="))
continue;
if (!GREEDY_REALLOC(all_ids, allocated, id_count + 1))
return log_oom();
id = &all_ids[id_count];
r = sd_id128_from_string(((const char *)data) + strlen("_BOOT_ID="), &id->id);
if (r < 0) {
continue;
}
sd_journal_flush_matches(j);
r = sd_journal_add_match(j, data, length);
if (r < 0)
continue;
r = sd_journal_seek_head(j);
if (r < 0)
continue;
r = sd_journal_next(j);
if (r <= 0)
continue;
r = sd_journal_get_realtime_usec(j, &id->timestamp);
if (r < 0)
continue;
if (!find_first_boot && sd_id128_equal(id->id, *boot_id)) {
ref_boot_id = *id;
ref_boot_found = true;
}
id_count++;
}
*boot_id = SD_ID128_NULL;
sd_journal_flush_matches(j);
if (id_count == 0 || (!find_first_boot && !ref_boot_found))
return 0;
qsort(all_ids, id_count, sizeof(boot_id_t), boot_id_cmp);
if (find_first_boot)
id = all_ids;
else
id = bsearch(&ref_boot_id, all_ids, id_count, sizeof(boot_id_t), boot_id_cmp);
if (!id || (relative < 0 && ((id - all_ids) + relative) < 0) ||
(relative >= 0 && (unsigned long)((id - all_ids) + relative) >= id_count))
return 0;
id += relative;
*boot_id = id->id;
return 0;
}
static int add_boot(sd_journal *j) {
char match[9+32+1] = "_BOOT_ID=";
char *marker;
sd_id128_t boot_id;
int r, relative = 0;
assert(j);
if (!arg_boot_id)
return 0;
if (arg_boot_id_descriptor) {
marker = strchr(arg_boot_id_descriptor, ':');
if (marker) {
*marker = '\0';
marker++;
if (*marker == '\0')
relative = -1;
else {
r = safe_atoi(marker, &relative);
if (r < 0) {
log_error("Failed to parse relative boot ID number '%s'", marker);
return -EINVAL;
}
}
}
}
if (isempty(arg_boot_id_descriptor)) {
if (relative > 0) {
/* We cannot look into the future. Instead, we look
* into the past (starting from first boot). The ID
* will be looked up later */
boot_id = SD_ID128_NULL;
} else {
r = sd_id128_get_boot(&boot_id);
if (r < 0) {
log_error("Failed to get boot ID: %s", strerror(-r));
return r;
}
}
} else {
r = sd_id128_from_string(arg_boot_id_descriptor, &boot_id);
if (r < 0) {
log_error("Failed to parse boot ID: %s", strerror(-r));
return r;
}
}
r = get_relative_boot_id(j, &boot_id, relative);
if (r < 0) {
log_error("Failed to look up boot ID: %s", strerror(-r));
return r;
} else if (sd_id128_equal(boot_id, SD_ID128_NULL)) {
log_error("Failed to find boot ID");
return -1;
}
sd_id128_to_string(boot_id, match + 9);
r = sd_journal_add_match(j, match, strlen(match));
if (r < 0) {
log_error("Failed to add match: %s", strerror(-r));
return r;
}
r = sd_journal_add_conjunction(j);
if (r < 0)
return r;
return 0;
}
static int add_dmesg(sd_journal *j) {
@ -1195,7 +1367,9 @@ int main(int argc, char *argv[]) {
return EXIT_SUCCESS;
}
r = add_this_boot(j);
/* add_boot() must be called first!
* It may need to seek the journal to find parent boot IDs. */
r = add_boot(j);
if (r < 0)
return EXIT_FAILURE;