[systemd-devel] [PATCH v5] journalctl: Add support for showing messages from a previous boot
Jan Janssen
medhefgo at web.de
Fri Jun 28 08:26:30 PDT 2013
Unfortunately, order of sd_journal_enumerate_unique() is
undefined, so we have to sort the boot IDs. For that we
seach for any log entry with a specific boot ID and then
use the realtime stamp to order everything.
---
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
TODO | 1 -
man/journalctl.xml | 54 ++++++++---
shell-completion/bash/journalctl | 11 ++-
src/journal/journalctl.c | 196 ++++++++++++++++++++++++++++++++++++---
4 files changed, 235 insertions(+), 27 deletions(-)
diff --git a/TODO b/TODO
index 055d973..dd0f4e8 100644
--- a/TODO
+++ b/TODO
@@ -318,7 +318,6 @@ 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
diff --git a/man/journalctl.xml b/man/journalctl.xml
index fa29c41..83d8878 100644
--- a/man/journalctl.xml
+++ b/man/journalctl.xml
@@ -313,23 +313,51 @@
</varlistentry>
<varlistentry>
- <term><option>-b</option></term>
- <term><option>--this-boot</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>
+ <term><option>-b <optional><replaceable>ID</replaceable></optional></option></term>
+ <term><option>--boot=<optional><replaceable>ID</replaceable></optional></option></term>
+
+ <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>
@@ -699,6 +727,10 @@
<programlisting>journalctl /dev/sda</programlisting>
+ <para>Show all kernel logs from last boot:</para>
+
+ <programlisting>journalctl -k -b :</programlisting>
+
</refsect1>
<refsect1>
diff --git a/shell-completion/bash/journalctl b/shell-completion/bash/journalctl
index 5ab59c9..29bf6bc 100644
--- a/shell-completion/bash/journalctl
+++ b/shell-completion/bash/journalctl
@@ -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
diff --git a/src/journal/journalctl.c b/src/journal/journalctl.c
index 7baea23..ea6c938 100644
--- a/src/journal/journalctl.c
+++ b/src/journal/journalctl.c
@@ -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;
@@ -102,6 +103,11 @@ 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"
@@ -112,8 +118,8 @@ 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"
@@ -195,7 +201,8 @@ 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 },
@@ -228,7 +235,7 @@ 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) {
@@ -327,11 +334,17 @@ 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:
@@ -621,11 +634,170 @@ 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;
+
+ 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;
- return add_match_this_boot(j);
+ 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) {
@@ -1164,7 +1336,9 @@ 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;
--
1.8.3.1
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