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logs-show: move journal_find_boot_by_offset() and friends from journalctl.c

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This commit is contained in:
Yu Watanabe
2023-09-26 13:26:22 +09:00
parent f5257facb9
commit 8081939d1d
3 changed files with 217 additions and 213 deletions
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src/journal/journalctl.c
+1 -213
View File
@@ -175,12 +175,6 @@ static enum {
ACTION_LIST_FIELD_NAMES,
} arg_action = ACTION_SHOW;
typedef struct BootId {
sd_id128_t id;
usec_t first_usec;
usec_t last_usec;
} BootId;
static int add_matches_for_device(sd_journal *j, const char *devpath) {
_cleanup_(sd_device_unrefp) sd_device *device = NULL;
sd_device *d = NULL;
@@ -1225,212 +1219,6 @@ static int add_matches(sd_journal *j, char **args) {
return 0;
}
static int discover_next_boot(
sd_journal *j,
sd_id128_t previous_boot_id,
bool advance_older,
BootId *ret) {
BootId boot;
int r;
assert(j);
assert(ret);
/* We expect the journal to be on the last position of a boot
* (in relation to the direction we are going), so that the next
* invocation of sd_journal_next/previous will be from a different
* boot. We then collect any information we desire and then jump
* to the last location of the new boot by using a _BOOT_ID match
* coming from the other journal direction. */
/* Make sure we aren't restricted by any _BOOT_ID matches, so that
* we can actually advance to a *different* boot. */
sd_journal_flush_matches(j);
do {
if (advance_older)
r = sd_journal_previous(j);
else
r = sd_journal_next(j);
if (r < 0)
return r;
else if (r == 0) {
*ret = (BootId) {};
return 0; /* End of journal, yay. */
}
r = sd_journal_get_monotonic_usec(j, NULL, &boot.id);
if (r < 0)
return r;
/* We iterate through this in a loop, until the boot ID differs from the previous one. Note that
* normally, this will only require a single iteration, as we moved to the last entry of the previous
* boot entry already. However, it might happen that the per-journal-field entry arrays are less
* complete than the main entry array, and hence might reference an entry that's not actually the last
* one of the boot ID as last one. Let's hence use the per-field array is initial seek position to
* speed things up, but let's not trust that it is complete, and hence, manually advance as
* necessary. */
} while (sd_id128_equal(boot.id, previous_boot_id));
r = sd_journal_get_realtime_usec(j, &boot.first_usec);
if (r < 0)
return r;
/* Now seek to the last occurrence of this boot ID. */
r = add_match_boot_id(j, boot.id);
if (r < 0)
return r;
if (advance_older)
r = sd_journal_seek_head(j);
else
r = sd_journal_seek_tail(j);
if (r < 0)
return r;
if (advance_older)
r = sd_journal_next(j);
else
r = sd_journal_previous(j);
if (r < 0)
return r;
else if (r == 0)
return log_debug_errno(SYNTHETIC_ERRNO(ENODATA),
"Whoopsie! We found a boot ID but can't read its last entry."); /* This shouldn't happen. We just came from this very boot ID. */
r = sd_journal_get_realtime_usec(j, &boot.last_usec);
if (r < 0)
return r;
sd_journal_flush_matches(j);
*ret = boot;
return 1;
}
static int journal_find_boot_by_id(sd_journal *j, sd_id128_t boot_id) {
int r;
assert(j);
assert(!sd_id128_is_null(boot_id));
sd_journal_flush_matches(j);
r = add_match_boot_id(j, boot_id);
if (r < 0)
return r;
r = sd_journal_seek_head(j); /* seek to oldest */
if (r < 0)
return r;
r = sd_journal_next(j); /* read the oldest entry */
if (r < 0)
return r;
/* At this point the read pointer is positioned at the oldest occurrence of the reference boot ID.
* After flushing the matches, one more invocation of _previous() will hence place us at the
* following entry, which must then have an older boot ID */
sd_journal_flush_matches(j);
return r > 0;
}
static int journal_find_boot_by_offset(sd_journal *j, int offset, sd_id128_t *ret) {
bool advance_older;
int r;
assert(j);
assert(ret);
/* Adjust for the asymmetry that offset 0 is the last (and current) boot, while 1 is considered the
* (chronological) first boot in the journal. */
advance_older = offset <= 0;
if (advance_older)
r = sd_journal_seek_tail(j); /* seek to newest */
else
r = sd_journal_seek_head(j); /* seek to oldest */
if (r < 0)
return r;
/* No sd_journal_next()/_previous() here.
*
* At this point the read pointer is positioned after the newest/before the oldest entry in the whole
* journal. The next invocation of _previous()/_next() will hence position us at the newest/oldest
* entry we have. */
sd_id128_t boot_id = SD_ID128_NULL;
for (int off = !advance_older; ; off += advance_older ? -1 : 1) {
BootId boot;
r = discover_next_boot(j, boot_id, advance_older, &boot);
if (r < 0)
return r;
if (r == 0) {
*ret = SD_ID128_NULL;
return false;
}
boot_id = boot.id;
log_debug("Found boot ID %s by offset %i", SD_ID128_TO_STRING(boot_id), off);
if (off == offset)
break;
}
*ret = boot_id;
return true;
}
static int get_boots(sd_journal *j, BootId **ret_boots, size_t *ret_n_boots) {
_cleanup_free_ BootId *boots = NULL;
size_t n_boots = 0;
int r;
assert(j);
assert(ret_boots);
assert(ret_n_boots);
r = sd_journal_seek_head(j); /* seek to oldest */
if (r < 0)
return r;
/* No sd_journal_next()/_previous() here.
*
* At this point the read pointer is positioned before the oldest entry in the whole journal. The
* next invocation of _next() will hence position us at the oldest entry we have. */
sd_id128_t previous_boot_id = SD_ID128_NULL;
for (;;) {
BootId boot;
r = discover_next_boot(j, previous_boot_id, /* advance_older = */ false, &boot);
if (r < 0)
return r;
if (r == 0)
break;
previous_boot_id = boot.id;
FOREACH_ARRAY(i, boots, n_boots)
if (sd_id128_equal(i->id, boot.id))
/* The boot id is already stored, something wrong with the journal files.
* Exiting as otherwise this problem would cause an infinite loop. */
break;
if (!GREEDY_REALLOC(boots, n_boots + 1))
return -ENOMEM;
boots[n_boots++] = boot;
}
*ret_boots = TAKE_PTR(boots);
*ret_n_boots = n_boots;
return n_boots > 0;
}
static int list_boots(sd_journal *j) {
_cleanup_(table_unrefp) Table *table = NULL;
_cleanup_free_ BootId *boots = NULL;
@@ -1439,7 +1227,7 @@ static int list_boots(sd_journal *j) {
assert(j);
r = get_boots(j, &boots, &n_boots);
r = journal_get_boots(j, &boots, &n_boots);
if (r < 0)
return log_error_errno(r, "Failed to determine boots: %m");
if (r == 0)
src/shared/logs-show.c
+206
View File
@@ -1827,3 +1827,209 @@ int show_journal_by_unit(
return show_journal(f, j, mode, n_columns, not_before, how_many, flags, ellipsized);
}
static int discover_next_boot(
sd_journal *j,
sd_id128_t previous_boot_id,
bool advance_older,
BootId *ret) {
BootId boot;
int r;
assert(j);
assert(ret);
/* We expect the journal to be on the last position of a boot
* (in relation to the direction we are going), so that the next
* invocation of sd_journal_next/previous will be from a different
* boot. We then collect any information we desire and then jump
* to the last location of the new boot by using a _BOOT_ID match
* coming from the other journal direction. */
/* Make sure we aren't restricted by any _BOOT_ID matches, so that
* we can actually advance to a *different* boot. */
sd_journal_flush_matches(j);
do {
if (advance_older)
r = sd_journal_previous(j);
else
r = sd_journal_next(j);
if (r < 0)
return r;
else if (r == 0) {
*ret = (BootId) {};
return 0; /* End of journal, yay. */
}
r = sd_journal_get_monotonic_usec(j, NULL, &boot.id);
if (r < 0)
return r;
/* We iterate through this in a loop, until the boot ID differs from the previous one. Note that
* normally, this will only require a single iteration, as we moved to the last entry of the previous
* boot entry already. However, it might happen that the per-journal-field entry arrays are less
* complete than the main entry array, and hence might reference an entry that's not actually the last
* one of the boot ID as last one. Let's hence use the per-field array is initial seek position to
* speed things up, but let's not trust that it is complete, and hence, manually advance as
* necessary. */
} while (sd_id128_equal(boot.id, previous_boot_id));
r = sd_journal_get_realtime_usec(j, &boot.first_usec);
if (r < 0)
return r;
/* Now seek to the last occurrence of this boot ID. */
r = add_match_boot_id(j, boot.id);
if (r < 0)
return r;
if (advance_older)
r = sd_journal_seek_head(j);
else
r = sd_journal_seek_tail(j);
if (r < 0)
return r;
if (advance_older)
r = sd_journal_next(j);
else
r = sd_journal_previous(j);
if (r < 0)
return r;
else if (r == 0)
return log_debug_errno(SYNTHETIC_ERRNO(ENODATA),
"Whoopsie! We found a boot ID but can't read its last entry."); /* This shouldn't happen. We just came from this very boot ID. */
r = sd_journal_get_realtime_usec(j, &boot.last_usec);
if (r < 0)
return r;
sd_journal_flush_matches(j);
*ret = boot;
return 1;
}
int journal_find_boot_by_id(sd_journal *j, sd_id128_t boot_id) {
int r;
assert(j);
assert(!sd_id128_is_null(boot_id));
sd_journal_flush_matches(j);
r = add_match_boot_id(j, boot_id);
if (r < 0)
return r;
r = sd_journal_seek_head(j); /* seek to oldest */
if (r < 0)
return r;
r = sd_journal_next(j); /* read the oldest entry */
if (r < 0)
return r;
/* At this point the read pointer is positioned at the oldest occurrence of the reference boot ID.
* After flushing the matches, one more invocation of _previous() will hence place us at the
* following entry, which must then have an older boot ID */
sd_journal_flush_matches(j);
return r > 0;
}
int journal_find_boot_by_offset(sd_journal *j, int offset, sd_id128_t *ret) {
bool advance_older;
int r;
assert(j);
assert(ret);
/* Adjust for the asymmetry that offset 0 is the last (and current) boot, while 1 is considered the
* (chronological) first boot in the journal. */
advance_older = offset <= 0;
if (advance_older)
r = sd_journal_seek_tail(j); /* seek to newest */
else
r = sd_journal_seek_head(j); /* seek to oldest */
if (r < 0)
return r;
/* No sd_journal_next()/_previous() here.
*
* At this point the read pointer is positioned after the newest/before the oldest entry in the whole
* journal. The next invocation of _previous()/_next() will hence position us at the newest/oldest
* entry we have. */
sd_id128_t boot_id = SD_ID128_NULL;
for (int off = !advance_older; ; off += advance_older ? -1 : 1) {
BootId boot;
r = discover_next_boot(j, boot_id, advance_older, &boot);
if (r < 0)
return r;
if (r == 0) {
*ret = SD_ID128_NULL;
return false;
}
boot_id = boot.id;
log_debug("Found boot ID %s by offset %i", SD_ID128_TO_STRING(boot_id), off);
if (off == offset)
break;
}
*ret = boot_id;
return true;
}
int journal_get_boots(sd_journal *j, BootId **ret_boots, size_t *ret_n_boots) {
_cleanup_free_ BootId *boots = NULL;
size_t n_boots = 0;
int r;
assert(j);
assert(ret_boots);
assert(ret_n_boots);
r = sd_journal_seek_head(j); /* seek to oldest */
if (r < 0)
return r;
/* No sd_journal_next()/_previous() here.
*
* At this point the read pointer is positioned before the oldest entry in the whole journal. The
* next invocation of _next() will hence position us at the oldest entry we have. */
sd_id128_t previous_boot_id = SD_ID128_NULL;
for (;;) {
BootId boot;
r = discover_next_boot(j, previous_boot_id, /* advance_older = */ false, &boot);
if (r < 0)
return r;
if (r == 0)
break;
previous_boot_id = boot.id;
FOREACH_ARRAY(i, boots, n_boots)
if (sd_id128_equal(i->id, boot.id))
/* The boot id is already stored, something wrong with the journal files.
* Exiting as otherwise this problem would cause an infinite loop. */
break;
if (!GREEDY_REALLOC(boots, n_boots + 1))
return -ENOMEM;
boots[n_boots++] = boot;
}
*ret_boots = TAKE_PTR(boots);
*ret_n_boots = n_boots;
return n_boots > 0;
}
src/shared/logs-show.h
+10
View File
@@ -13,6 +13,12 @@
#include "output-mode.h"
#include "time-util.h"
typedef struct BootId {
sd_id128_t id;
usec_t first_usec;
usec_t last_usec;
} BootId;
int show_journal_entry(
FILE *f,
sd_journal *j,
@@ -65,3 +71,7 @@ void json_escape(
const char* p,
size_t l,
OutputFlags flags);
int journal_find_boot_by_id(sd_journal *j, sd_id128_t boot_id);
int journal_find_boot_by_offset(sd_journal *j, int offset, sd_id128_t *ret);
int journal_get_boots(sd_journal *j, BootId **ret_boots, size_t *ret_n_boots);