Merge branch 'journal'

1 files changed, 1573 insertions, 0 deletions

diff --git a/src/journal/sd-journal.c b/src/journal/sd-journal.c
new file mode 100644
index 0000000000..38e58f5732
--- /dev/null
+++ b/src/journal/sd-journal.c
@@ -0,0 +1,1573 @@
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
+
+/***
+  This file is part of systemd.
+
+  Copyright 2011 Lennart Poettering
+
+  systemd is free software; you can redistribute it and/or modify it
+  under the terms of the GNU General Public License as published by
+  the Free Software Foundation; either version 2 of the License, or
+  (at your option) any later version.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  General Public License for more details.
+
+  You should have received a copy of the GNU General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stddef.h>
+#include <unistd.h>
+#include <sys/inotify.h>
+
+#include "sd-journal.h"
+#include "journal-def.h"
+#include "journal-file.h"
+#include "hashmap.h"
+#include "list.h"
+#include "lookup3.h"
+#include "compress.h"
+#include "journal-internal.h"
+
+#define JOURNAL_FILES_MAX 1024
+
+static void detach_location(sd_journal *j) {
+        Iterator i;
+        JournalFile *f;
+
+        assert(j);
+
+        j->current_file = NULL;
+        j->current_field = 0;
+
+        HASHMAP_FOREACH(f, j->files, i)
+                f->current_offset = 0;
+}
+
+static void reset_location(sd_journal *j) {
+        assert(j);
+
+        detach_location(j);
+        zero(j->current_location);
+}
+
+static void init_location(Location *l, JournalFile *f, Object *o) {
+        assert(l);
+        assert(f);
+        assert(o->object.type == OBJECT_ENTRY);
+
+        l->type = LOCATION_DISCRETE;
+        l->seqnum = le64toh(o->entry.seqnum);
+        l->seqnum_id = f->header->seqnum_id;
+        l->realtime = le64toh(o->entry.realtime);
+        l->monotonic = le64toh(o->entry.monotonic);
+        l->boot_id = le64toh(o->entry.boot_id);
+        l->xor_hash = le64toh(o->entry.xor_hash);
+
+        l->seqnum_set = l->realtime_set = l->monotonic_set = l->xor_hash_set = true;
+}
+
+static void set_location(sd_journal *j, JournalFile *f, Object *o, uint64_t offset) {
+        assert(j);
+        assert(f);
+        assert(o);
+
+        init_location(&j->current_location, f, o);
+
+        j->current_file = f;
+        j->current_field = 0;
+
+        f->current_offset = offset;
+}
+
+static int same_field(const void *_a, size_t s, const void *_b, size_t t) {
+        const uint8_t *a = _a, *b = _b;
+        size_t j;
+        bool a_good = false, b_good = false, different = false;
+
+        for (j = 0; j < s && j < t; j++) {
+
+                if (a[j] == '=')
+                        a_good = true;
+                if (b[j] == '=')
+                        b_good = true;
+                if (a[j] != b[j])
+                        different = true;
+
+                if (a_good && b_good)
+                        return different ? 0 : 1;
+        }
+
+        return -EINVAL;
+}
+
+int sd_journal_add_match(sd_journal *j, const void *data, size_t size) {
+        Match *m, *after = NULL;
+        uint64_t le_hash;
+
+        assert(j);
+
+        if (size <= 0)
+                return -EINVAL;
+
+        assert(data);
+
+        le_hash = htole64(hash64(data, size));
+
+        LIST_FOREACH(matches, m, j->matches) {
+                int r;
+
+                if (m->le_hash == le_hash &&
+                    m->size == size &&
+                    memcmp(m->data, data, size) == 0)
+                        return 0;
+
+                r = same_field(data, size, m->data, m->size);
+                if (r < 0)
+                        return r;
+                else if (r > 0)
+                        after = m;
+        }
+
+        m = new0(Match, 1);
+        if (!m)
+                return -ENOMEM;
+
+        m->size = size;
+
+        m->data = malloc(m->size);
+        if (!m->data) {
+                free(m);
+                return -ENOMEM;
+        }
+
+        memcpy(m->data, data, size);
+        m->le_hash = le_hash;
+
+        /* Matches for the same fields we order adjacent to each
+         * other */
+        LIST_INSERT_AFTER(Match, matches, j->matches, after, m);
+        j->n_matches ++;
+
+        detach_location(j);
+
+        return 0;
+}
+
+void sd_journal_flush_matches(sd_journal *j) {
+        assert(j);
+
+        while (j->matches) {
+                Match *m = j->matches;
+
+                LIST_REMOVE(Match, matches, j->matches, m);
+                free(m->data);
+                free(m);
+        }
+
+        j->n_matches = 0;
+
+        detach_location(j);
+}
+
+static int compare_order(JournalFile *af, Object *ao,
+                         JournalFile *bf, Object *bo) {
+
+        uint64_t a, b;
+
+        assert(af);
+        assert(ao);
+        assert(bf);
+        assert(bo);
+
+        /* We operate on two different files here, hence we can access
+         * two objects at the same time, which we normally can't.
+         *
+         * If contents and timestamps match, these entries are
+         * identical, even if the seqnum does not match */
+
+        if (sd_id128_equal(ao->entry.boot_id, bo->entry.boot_id) &&
+            ao->entry.monotonic == bo->entry.monotonic &&
+            ao->entry.realtime == bo->entry.realtime &&
+            ao->entry.xor_hash == bo->entry.xor_hash)
+                return 0;
+
+        if (sd_id128_equal(af->header->seqnum_id, bf->header->seqnum_id)) {
+
+                /* If this is from the same seqnum source, compare
+                 * seqnums */
+                a = le64toh(ao->entry.seqnum);
+                b = le64toh(bo->entry.seqnum);
+
+                if (a < b)
+                        return -1;
+                if (a > b)
+                        return 1;
+
+                /* Wow! This is weird, different data but the same
+                 * seqnums? Something is borked, but let's make the
+                 * best of it and compare by time. */
+        }
+
+        if (sd_id128_equal(ao->entry.boot_id, bo->entry.boot_id)) {
+
+                /* If the boot id matches compare monotonic time */
+                a = le64toh(ao->entry.monotonic);
+                b = le64toh(bo->entry.monotonic);
+
+                if (a < b)
+                        return -1;
+                if (a > b)
+                        return 1;
+        }
+
+        /* Otherwise compare UTC time */
+        a = le64toh(ao->entry.realtime);
+        b = le64toh(ao->entry.realtime);
+
+        if (a < b)
+                return -1;
+        if (a > b)
+                return 1;
+
+        /* Finally, compare by contents */
+        a = le64toh(ao->entry.xor_hash);
+        b = le64toh(ao->entry.xor_hash);
+
+        if (a < b)
+                return -1;
+        if (a > b)
+                return 1;
+
+        return 0;
+}
+
+static int compare_with_location(JournalFile *af, Object *ao, Location *l) {
+        uint64_t a;
+
+        assert(af);
+        assert(ao);
+        assert(l);
+        assert(l->type == LOCATION_DISCRETE);
+
+        if (l->monotonic_set &&
+            sd_id128_equal(ao->entry.boot_id, l->boot_id) &&
+            l->realtime_set &&
+            le64toh(ao->entry.realtime) == l->realtime &&
+            l->xor_hash_set &&
+            le64toh(ao->entry.xor_hash) == l->xor_hash)
+                return 0;
+
+        if (l->seqnum_set &&
+            sd_id128_equal(af->header->seqnum_id, l->seqnum_id)) {
+
+                a = le64toh(ao->entry.seqnum);
+
+                if (a < l->seqnum)
+                        return -1;
+                if (a > l->seqnum)
+                        return 1;
+        }
+
+        if (l->monotonic_set &&
+            sd_id128_equal(ao->entry.boot_id, l->boot_id)) {
+
+                a = le64toh(ao->entry.monotonic);
+
+                if (a < l->monotonic)
+                        return -1;
+                if (a > l->monotonic)
+                        return 1;
+        }
+
+        if (l->realtime_set) {
+
+                a = le64toh(ao->entry.realtime);
+
+                if (a < l->realtime)
+                        return -1;
+                if (a > l->realtime)
+                        return 1;
+        }
+
+        if (l->xor_hash_set) {
+                a = le64toh(ao->entry.xor_hash);
+
+                if (a < l->xor_hash)
+                        return -1;
+                if (a > l->xor_hash)
+                        return 1;
+        }
+
+        return 0;
+}
+
+static int find_location(sd_journal *j, JournalFile *f, direction_t direction, Object **ret, uint64_t *offset) {
+        Object *o = NULL;
+        uint64_t p = 0;
+        int r;
+
+        assert(j);
+
+        if (!j->matches) {
+                /* No matches is simple */
+
+                if (j->current_location.type == LOCATION_HEAD)
+                        r = journal_file_next_entry(f, NULL, 0, DIRECTION_DOWN, &o, &p);
+                else if (j->current_location.type == LOCATION_TAIL)
+                        r = journal_file_next_entry(f, NULL, 0, DIRECTION_UP, &o, &p);
+                else if (j->current_location.seqnum_set &&
+                         sd_id128_equal(j->current_location.seqnum_id, f->header->seqnum_id))
+                        r = journal_file_move_to_entry_by_seqnum(f, j->current_location.seqnum, direction, &o, &p);
+                else if (j->current_location.monotonic_set)
+                        r = journal_file_move_to_entry_by_monotonic(f, j->current_location.boot_id, j->current_location.monotonic, direction, &o, &p);
+                else if (j->current_location.realtime_set)
+                        r = journal_file_move_to_entry_by_realtime(f, j->current_location.realtime, direction, &o, &p);
+                else
+                        r = journal_file_next_entry(f, NULL, 0, direction, &o, &p);
+
+                if (r <= 0)
+                        return r;
+
+        } else  {
+                Match *m, *term_match = NULL;
+                Object *to = NULL;
+                uint64_t tp = 0;
+
+                /* We have matches, first, let's jump to the monotonic
+                 * position if we have any, since it implies a
+                 * match. */
+
+                if (j->current_location.type == LOCATION_DISCRETE &&
+                    j->current_location.monotonic_set) {
+
+                        r = journal_file_move_to_entry_by_monotonic(f, j->current_location.boot_id, j->current_location.monotonic, direction, &o, &p);
+                        if (r <= 0)
+                                return r;
+                }
+
+                LIST_FOREACH(matches, m, j->matches) {
+                        Object *c, *d;
+                        uint64_t cp, dp;
+
+                        r = journal_file_find_data_object_with_hash(f, m->data, m->size, m->le_hash, &d, &dp);
+                        if (r <= 0)
+                                return r;
+
+                        if (j->current_location.type == LOCATION_HEAD)
+                                r = journal_file_next_entry_for_data(f, NULL, 0, dp, DIRECTION_DOWN, &c, &cp);
+                        else if (j->current_location.type == LOCATION_TAIL)
+                                r = journal_file_next_entry_for_data(f, NULL, 0, dp, DIRECTION_UP, &c, &cp);
+                        else if (j->current_location.seqnum_set &&
+                                 sd_id128_equal(j->current_location.seqnum_id, f->header->seqnum_id))
+                                r = journal_file_move_to_entry_by_seqnum_for_data(f, dp, j->current_location.seqnum, direction, &c, &cp);
+                        else if (j->current_location.realtime_set)
+                                r = journal_file_move_to_entry_by_realtime_for_data(f, dp, j->current_location.realtime, direction, &c, &cp);
+                        else
+                                r = journal_file_next_entry_for_data(f, NULL, 0, dp, direction, &c, &cp);
+
+                        if (!term_match) {
+                                term_match = m;
+
+                                if (r > 0) {
+                                        to = c;
+                                        tp = cp;
+                                }
+                        } else if (same_field(term_match->data, term_match->size, m->data, m->size)) {
+
+                                /* Same field as previous match... */
+                                if (r > 0) {
+
+                                        /* Find the earliest of the OR matches */
+
+                                        if (!to ||
+                                            (direction == DIRECTION_DOWN && cp < tp) ||
+                                            (direction == DIRECTION_UP && cp > tp)) {
+                                                to = c;
+                                                tp = cp;
+                                        }
+
+                                }
+
+                        } else {
+
+                                /* Previous term is finished, did anything match? */
+                                if (!to)
+                                        return 0;
+
+                                /* Find the last of the AND matches */
+                                if (!o ||
+                                    (direction == DIRECTION_DOWN && tp > p) ||
+                                    (direction == DIRECTION_UP && tp < p)) {
+                                        o = to;
+                                        p = tp;
+                                }
+
+                                term_match = m;
+
+                                if (r > 0) {
+                                        to = c;
+                                        tp = cp;
+                                } else {
+                                        to = NULL;
+                                        tp = 0;
+                                }
+                        }
+                }
+
+                /* Last term is finished, did anything match? */
+                if (!to)
+                        return 0;
+
+                if (!o ||
+                    (direction == DIRECTION_DOWN && tp > p) ||
+                    (direction == DIRECTION_UP && tp < p)) {
+                        o = to;
+                        p = tp;
+                }
+
+                if (!o)
+                        return 0;
+        }
+
+        if (ret)
+                *ret = o;
+
+        if (offset)
+                *offset = p;
+
+        return 1;
+}
+
+static int next_with_matches(sd_journal *j, JournalFile *f, direction_t direction, Object **ret, uint64_t *offset) {
+        int r;
+        uint64_t cp;
+        Object *c;
+
+        assert(j);
+        assert(f);
+        assert(ret);
+        assert(offset);
+
+        c = *ret;
+        cp = *offset;
+
+        if (!j->matches) {
+                /* No matches is easy */
+
+                r = journal_file_next_entry(f, c, cp, direction, &c, &cp);
+                if (r <= 0)
+                        return r;
+
+                if (ret)
+                        *ret = c;
+                if (offset)
+                        *offset = cp;
+                return 1;
+        }
+
+        /* So there are matches we have to adhere to, let's find the
+         * first entry that matches all of them */
+
+        for (;;) {
+                uint64_t np, n;
+                bool found, term_result = false;
+                Match *m, *term_match = NULL;
+                Object *npo = NULL;
+
+                n = journal_file_entry_n_items(c);
+
+                /* Make sure we don't match the entry we are starting
+                 * from. */
+                found = cp > *offset;
+
+                np = 0;
+                LIST_FOREACH(matches, m, j->matches) {
+                        uint64_t q, k;
+                        Object *qo = NULL;
+
+                        /* Let's check if this is the beginning of a
+                         * new term, i.e. has a different field prefix
+                         * as the preceeding match. */
+                        if (!term_match) {
+                                term_match = m;
+                                term_result = false;
+                        } else if (!same_field(term_match->data, term_match->size, m->data, m->size)) {
+                                if (!term_result)
+                                        found = false;
+
+                                term_match = m;
+                                term_result = false;
+                        }
+
+                        for (k = 0; k < n; k++)
+                                if (c->entry.items[k].hash == m->le_hash)
+                                        break;
+
+                        if (k >= n) {
+                                /* Hmm, didn't find any field that
+                                 * matched this rule, so ignore this
+                                 * match. Go on with next match */
+                                continue;
+                        }
+
+                        term_result = true;
+
+                        /* Hmm, so, this field matched, let's remember
+                         * where we'd have to try next, in case the other
+                         * matches are not OK */
+
+                        r = journal_file_next_entry_for_data(f, c, cp, le64toh(c->entry.items[k].object_offset), direction, &qo, &q);
+                        if (r > 0) {
+
+                                if (direction == DIRECTION_DOWN) {
+                                        if (q > np) {
+                                                np = q;
+                                                npo = qo;
+                                        }
+                                } else {
+                                        if (np == 0 || q < np) {
+                                                np = q;
+                                                npo = qo;
+                                        }
+                                }
+                        }
+                }
+
+                /* Check the last term */
+                if (term_match && !term_result)
+                        found = false;
+
+                /* Did this entry match against all matches? */
+                if (found) {
+                        if (ret)
+                                *ret = c;
+                        if (offset)
+                                *offset = cp;
+                        return 1;
+                }
+
+                /* Did we find a subsequent entry? */
+                if (np == 0)
+                        return 0;
+
+                /* Hmm, ok, this entry only matched partially, so
+                 * let's try another one */
+                cp = np;
+                c = npo;
+        }
+}
+
+static int next_beyond_location(sd_journal *j, JournalFile *f, direction_t direction, Object **ret, uint64_t *offset) {
+        Object *c;
+        uint64_t cp;
+        int compare_value, r;
+
+        assert(j);
+        assert(f);
+
+        if (f->current_offset > 0) {
+                cp = f->current_offset;
+
+                r = journal_file_move_to_object(f, OBJECT_ENTRY, cp, &c);
+                if (r < 0)
+                        return r;
+
+                r = next_with_matches(j, f, direction, &c, &cp);
+                if (r <= 0)
+                        return r;
+
+                compare_value = 1;
+        } else {
+                r = find_location(j, f, direction, &c, &cp);
+                if (r <= 0)
+                        return r;
+
+                compare_value = 0;
+        }
+
+        for (;;) {
+                bool found;
+
+                if (j->current_location.type == LOCATION_DISCRETE) {
+                        int k;
+
+                        k = compare_with_location(f, c, &j->current_location);
+                        if (direction == DIRECTION_DOWN)
+                                found = k >= compare_value;
+                        else
+                                found = k <= -compare_value;
+                } else
+                        found = true;
+
+                if (found) {
+                        if (ret)
+                                *ret = c;
+                        if (offset)
+                                *offset = cp;
+                        return 1;
+                }
+
+                r = next_with_matches(j, f, direction, &c, &cp);
+                if (r <= 0)
+                        return r;
+        }
+}
+
+static int real_journal_next(sd_journal *j, direction_t direction) {
+        JournalFile *f, *new_current = NULL;
+        Iterator i;
+        int r;
+        uint64_t new_offset = 0;
+        Object *new_entry = NULL;
+
+        assert(j);
+
+        HASHMAP_FOREACH(f, j->files, i) {
+                Object *o;
+                uint64_t p;
+                bool found;
+
+                r = next_beyond_location(j, f, direction, &o, &p);
+                if (r < 0)
+                        return r;
+                else if (r == 0)
+                        continue;
+
+                if (!new_current)
+                        found = true;
+                else {
+                        int k;
+
+                        k = compare_order(f, o, new_current, new_entry);
+
+                        if (direction == DIRECTION_DOWN)
+                                found = k < 0;
+                        else
+                                found = k > 0;
+                }
+
+                if (found) {
+                        new_current = f;
+                        new_entry = o;
+                        new_offset = p;
+                }
+        }
+
+        if (!new_current)
+                return 0;
+
+        set_location(j, new_current, new_entry, new_offset);
+
+        return 1;
+}
+
+int sd_journal_next(sd_journal *j) {
+        return real_journal_next(j, DIRECTION_DOWN);
+}
+
+int sd_journal_previous(sd_journal *j) {
+        return real_journal_next(j, DIRECTION_UP);
+}
+
+int sd_journal_next_skip(sd_journal *j, uint64_t skip) {
+        int c = 0, r;
+
+        assert(j);
+
+        while (skip > 0) {
+                r = sd_journal_next(j);
+                if (r < 0)
+                        return r;
+
+                if (r == 0)
+                        return c;
+
+                skip--;
+                c++;
+        }
+
+        return c;
+}
+
+int sd_journal_previous_skip(sd_journal *j, uint64_t skip) {
+        int c = 0, r;
+
+        assert(j);
+
+        while (skip > 0) {
+                r = sd_journal_previous(j);
+                if (r < 0)
+                        return r;
+
+                if (r == 0)
+                        return c;
+
+                skip--;
+                c++;
+        }
+
+        return 1;
+}
+
+int sd_journal_get_cursor(sd_journal *j, char **cursor) {
+        Object *o;
+        int r;
+        char bid[33], sid[33];
+
+        assert(j);
+        assert(cursor);
+
+        if (!j->current_file || j->current_file->current_offset <= 0)
+                return -EADDRNOTAVAIL;
+
+        r = journal_file_move_to_object(j->current_file, OBJECT_ENTRY, j->current_file->current_offset, &o);
+        if (r < 0)
+                return r;
+
+        sd_id128_to_string(j->current_file->header->seqnum_id, sid);
+        sd_id128_to_string(o->entry.boot_id, bid);
+
+        if (asprintf(cursor,
+                     "s=%s;i=%llx;b=%s;m=%llx;t=%llx;x=%llx;p=%s",
+                     sid, (unsigned long long) le64toh(o->entry.seqnum),
+                     bid, (unsigned long long) le64toh(o->entry.monotonic),
+                     (unsigned long long) le64toh(o->entry.realtime),
+                     (unsigned long long) le64toh(o->entry.xor_hash),
+                     file_name_from_path(j->current_file->path)) < 0)
+                return -ENOMEM;
+
+        return 1;
+}
+
+int sd_journal_seek_cursor(sd_journal *j, const char *cursor) {
+        char *w;
+        size_t l;
+        char *state;
+        unsigned long long seqnum, monotonic, realtime, xor_hash;
+        bool
+                seqnum_id_set = false,
+                seqnum_set = false,
+                boot_id_set = false,
+                monotonic_set = false,
+                realtime_set = false,
+                xor_hash_set = false;
+        sd_id128_t seqnum_id, boot_id;
+
+        assert(j);
+        assert(cursor);
+
+        FOREACH_WORD_SEPARATOR(w, l, cursor, ";", state) {
+                char *item;
+                int k = 0;
+
+                if (l < 2 || w[1] != '=')
+                        return -EINVAL;
+
+                item = strndup(w, l);
+                if (!item)
+                        return -ENOMEM;
+
+                switch (w[0]) {
+
+                case 's':
+                        seqnum_id_set = true;
+                        k = sd_id128_from_string(w+2, &seqnum_id);
+                        break;
+
+                case 'i':
+                        seqnum_set = true;
+                        if (sscanf(w+2, "%llx", &seqnum) != 1)
+                                k = -EINVAL;
+                        break;
+
+                case 'b':
+                        boot_id_set = true;
+                        k = sd_id128_from_string(w+2, &boot_id);
+                        break;
+
+                case 'm':
+                        monotonic_set = true;
+                        if (sscanf(w+2, "%llx", &monotonic) != 1)
+                                k = -EINVAL;
+                        break;
+
+                case 't':
+                        realtime_set = true;
+                        if (sscanf(w+2, "%llx", &realtime) != 1)
+                                k = -EINVAL;
+                        break;
+
+                case 'x':
+                        xor_hash_set = true;
+                        if (sscanf(w+2, "%llx", &xor_hash) != 1)
+                                k = -EINVAL;
+                        break;
+                }
+
+                free(item);
+
+                if (k < 0)
+                        return k;
+        }
+
+        if ((!seqnum_set || !seqnum_id_set) &&
+            (!monotonic_set || !boot_id_set) &&
+            !realtime_set)
+                return -EINVAL;
+
+        reset_location(j);
+
+        j->current_location.type = LOCATION_DISCRETE;
+
+        if (realtime_set) {
+                j->current_location.realtime = (uint64_t) realtime;
+                j->current_location.realtime_set = true;
+        }
+
+        if (seqnum_set && seqnum_id_set) {
+                j->current_location.seqnum = (uint64_t) seqnum;
+                j->current_location.seqnum_id = seqnum_id;
+                j->current_location.seqnum_set = true;
+        }
+
+        if (monotonic_set && boot_id_set) {
+                j->current_location.monotonic = (uint64_t) monotonic;
+                j->current_location.boot_id = boot_id;
+                j->current_location.monotonic_set = true;
+        }
+
+        if (xor_hash_set) {
+                j->current_location.xor_hash = (uint64_t) xor_hash;
+                j->current_location.xor_hash_set = true;
+        }
+
+        return 0;
+}
+
+int sd_journal_seek_monotonic_usec(sd_journal *j, sd_id128_t boot_id, uint64_t usec) {
+        assert(j);
+
+        reset_location(j);
+        j->current_location.type = LOCATION_DISCRETE;
+        j->current_location.boot_id = boot_id;
+        j->current_location.monotonic = usec;
+        j->current_location.monotonic_set = true;
+
+        return 0;
+}
+
+int sd_journal_seek_realtime_usec(sd_journal *j, uint64_t usec) {
+        assert(j);
+
+        reset_location(j);
+        j->current_location.type = LOCATION_DISCRETE;
+        j->current_location.realtime = usec;
+        j->current_location.realtime_set = true;
+
+        return 0;
+}
+
+int sd_journal_seek_head(sd_journal *j) {
+        assert(j);
+
+        reset_location(j);
+        j->current_location.type = LOCATION_HEAD;
+
+        return 0;
+}
+
+int sd_journal_seek_tail(sd_journal *j) {
+        assert(j);
+
+        reset_location(j);
+        j->current_location.type = LOCATION_TAIL;
+
+        return 0;
+}
+
+static int add_file(sd_journal *j, const char *prefix, const char *dir, const char *filename) {
+        char *fn;
+        int r;
+        JournalFile *f;
+
+        assert(j);
+        assert(prefix);
+        assert(filename);
+
+        if ((j->flags & SD_JOURNAL_SYSTEM_ONLY) &&
+            !startswith(filename, "system.journal"))
+                return 0;
+
+        if (dir)
+                fn = join(prefix, "/", dir, "/", filename, NULL);
+        else
+                fn = join(prefix, "/", filename, NULL);
+
+        if (!fn)
+                return -ENOMEM;
+
+        if (hashmap_get(j->files, fn)) {
+                free(fn);
+                return 0;
+        }
+
+        if (hashmap_size(j->files) >= JOURNAL_FILES_MAX) {
+                log_debug("Too many open journal files, not adding %s, ignoring.", fn);
+                free(fn);
+                return 0;
+        }
+
+        r = journal_file_open(fn, O_RDONLY, 0, NULL, &f);
+        free(fn);
+
+        if (r < 0) {
+                if (errno == ENOENT)
+                        return 0;
+
+                return r;
+        }
+
+        /* journal_file_dump(f); */
+
+        r = hashmap_put(j->files, f->path, f);
+        if (r < 0) {
+                journal_file_close(f);
+                return r;
+        }
+
+        log_debug("File %s got added.", f->path);
+
+        return 0;
+}
+
+static int remove_file(sd_journal *j, const char *prefix, const char *dir, const char *filename) {
+        char *fn;
+        JournalFile *f;
+
+        assert(j);
+        assert(prefix);
+        assert(filename);
+
+        if (dir)
+                fn = join(prefix, "/", dir, "/", filename, NULL);
+        else
+                fn = join(prefix, "/", filename, NULL);
+
+        if (!fn)
+                return -ENOMEM;
+
+        f = hashmap_get(j->files, fn);
+        free(fn);
+
+        if (!f)
+                return 0;
+
+        hashmap_remove(j->files, f->path);
+        journal_file_close(f);
+
+        log_debug("File %s got removed.", f->path);
+        return 0;
+}
+
+static int add_directory(sd_journal *j, const char *prefix, const char *dir) {
+        char *fn;
+        int r;
+        DIR *d;
+        int wd;
+        sd_id128_t id, mid;
+
+        assert(j);
+        assert(prefix);
+        assert(dir);
+
+        if ((j->flags & SD_JOURNAL_LOCAL_ONLY) &&
+            (sd_id128_from_string(dir, &id) < 0 ||
+             sd_id128_get_machine(&mid) < 0 ||
+             !sd_id128_equal(id, mid)))
+            return 0;
+
+        fn = join(prefix, "/", dir, NULL);
+        if (!fn)
+                return -ENOMEM;
+
+        d = opendir(fn);
+
+        if (!d) {
+                free(fn);
+                if (errno == ENOENT)
+                        return 0;
+
+                return -errno;
+        }
+
+        wd = inotify_add_watch(j->inotify_fd, fn,
+                               IN_CREATE|IN_MOVED_TO|IN_MODIFY|IN_ATTRIB|IN_DELETE|
+                               IN_DELETE_SELF|IN_MOVE_SELF|IN_UNMOUNT|
+                               IN_DONT_FOLLOW|IN_ONLYDIR);
+        if (wd > 0) {
+                if (hashmap_put(j->inotify_wd_dirs, INT_TO_PTR(wd), fn) < 0)
+                        inotify_rm_watch(j->inotify_fd, wd);
+                else
+                        fn = NULL;
+        }
+
+        free(fn);
+
+        for (;;) {
+                struct dirent buf, *de;
+
+                r = readdir_r(d, &buf, &de);
+                if (r != 0 || !de)
+                        break;
+
+                if (!dirent_is_file_with_suffix(de, ".journal"))
+                        continue;
+
+                r = add_file(j, prefix, dir, de->d_name);
+                if (r < 0)
+                        log_debug("Failed to add file %s/%s/%s: %s", prefix, dir, de->d_name, strerror(-r));
+        }
+
+        closedir(d);
+
+        log_debug("Directory %s/%s got added.", prefix, dir);
+
+        return 0;
+}
+
+static void remove_directory_wd(sd_journal *j, int wd) {
+        char *p;
+
+        assert(j);
+        assert(wd > 0);
+
+        if (j->inotify_fd >= 0)
+                inotify_rm_watch(j->inotify_fd, wd);
+
+        p = hashmap_remove(j->inotify_wd_dirs, INT_TO_PTR(wd));
+
+        if (p) {
+                log_debug("Directory %s got removed.", p);
+                free(p);
+        }
+}
+
+static void add_root_wd(sd_journal *j, const char *p) {
+        int wd;
+        char *k;
+
+        assert(j);
+        assert(p);
+
+        wd = inotify_add_watch(j->inotify_fd, p,
+                               IN_CREATE|IN_MOVED_TO|IN_MODIFY|IN_ATTRIB|IN_DELETE|
+                               IN_DONT_FOLLOW|IN_ONLYDIR);
+        if (wd <= 0)
+                return;
+
+        k = strdup(p);
+        if (!k || hashmap_put(j->inotify_wd_roots, INT_TO_PTR(wd), k) < 0) {
+                inotify_rm_watch(j->inotify_fd, wd);
+                free(k);
+        }
+}
+
+static void remove_root_wd(sd_journal *j, int wd) {
+        char *p;
+
+        assert(j);
+        assert(wd > 0);
+
+        if (j->inotify_fd >= 0)
+                inotify_rm_watch(j->inotify_fd, wd);
+
+        p = hashmap_remove(j->inotify_wd_roots, INT_TO_PTR(wd));
+
+        if (p) {
+                log_debug("Root %s got removed.", p);
+                free(p);
+        }
+}
+
+int sd_journal_open(sd_journal **ret, int flags) {
+        sd_journal *j;
+        const char *p;
+        const char search_paths[] =
+                "/run/log/journal\0"
+                "/var/log/journal\0";
+        int r;
+
+        assert(ret);
+
+        j = new0(sd_journal, 1);
+        if (!j)
+                return -ENOMEM;
+
+        j->flags = flags;
+
+        j->inotify_fd = inotify_init1(IN_NONBLOCK|IN_CLOEXEC);
+        if (j->inotify_fd < 0) {
+                r = -errno;
+                goto fail;
+        }
+
+        j->files = hashmap_new(string_hash_func, string_compare_func);
+        if (!j->files) {
+                r = -ENOMEM;
+                goto fail;
+        }
+
+        j->inotify_wd_dirs = hashmap_new(trivial_hash_func, trivial_compare_func);
+        j->inotify_wd_roots = hashmap_new(trivial_hash_func, trivial_compare_func);
+
+        if (!j->inotify_wd_dirs || !j->inotify_wd_roots) {
+                r = -ENOMEM;
+                goto fail;
+        }
+
+        /* We ignore most errors here, since the idea is to only open
+         * what's actually accessible, and ignore the rest. */
+
+        NULSTR_FOREACH(p, search_paths) {
+                DIR *d;
+
+                if ((flags & SD_JOURNAL_RUNTIME_ONLY) &&
+                    !path_startswith(p, "/run"))
+                        continue;
+
+                d = opendir(p);
+                if (!d) {
+                        if (errno != ENOENT)
+                                log_debug("Failed to open %s: %m", p);
+                        continue;
+                }
+
+                add_root_wd(j, p);
+
+                for (;;) {
+                        struct dirent buf, *de;
+                        sd_id128_t id;
+
+                        r = readdir_r(d, &buf, &de);
+                        if (r != 0 || !de)
+                                break;
+
+                        if (dirent_is_file_with_suffix(de, ".journal")) {
+                                r = add_file(j, p, NULL, de->d_name);
+                                if (r < 0)
+                                        log_debug("Failed to add file %s/%s: %s", p, de->d_name, strerror(-r));
+
+                        } else if ((de->d_type == DT_DIR || de->d_type == DT_UNKNOWN) &&
+                                   sd_id128_from_string(de->d_name, &id) >= 0) {
+
+                                r = add_directory(j, p, de->d_name);
+                                if (r < 0)
+                                        log_debug("Failed to add directory %s/%s: %s", p, de->d_name, strerror(-r));
+                        }
+                }
+
+                closedir(d);
+        }
+
+        *ret = j;
+        return 0;
+
+fail:
+        sd_journal_close(j);
+
+        return r;
+};
+
+void sd_journal_close(sd_journal *j) {
+        assert(j);
+
+        if (j->inotify_wd_dirs) {
+                void *k;
+
+                while ((k = hashmap_first_key(j->inotify_wd_dirs)))
+                        remove_directory_wd(j, PTR_TO_INT(k));
+
+                hashmap_free(j->inotify_wd_dirs);
+        }
+
+        if (j->inotify_wd_roots) {
+                void *k;
+
+                while ((k = hashmap_first_key(j->inotify_wd_roots)))
+                        remove_root_wd(j, PTR_TO_INT(k));
+
+                hashmap_free(j->inotify_wd_roots);
+        }
+
+        if (j->files) {
+                JournalFile *f;
+
+                while ((f = hashmap_steal_first(j->files)))
+                        journal_file_close(f);
+
+                hashmap_free(j->files);
+        }
+
+        sd_journal_flush_matches(j);
+
+        if (j->inotify_fd >= 0)
+                close_nointr_nofail(j->inotify_fd);
+
+        free(j);
+}
+
+int sd_journal_get_realtime_usec(sd_journal *j, uint64_t *ret) {
+        Object *o;
+        JournalFile *f;
+        int r;
+
+        assert(j);
+        assert(ret);
+
+        f = j->current_file;
+        if (!f)
+                return -EADDRNOTAVAIL;
+
+        if (f->current_offset <= 0)
+                return -EADDRNOTAVAIL;
+
+        r = journal_file_move_to_object(f, OBJECT_ENTRY, f->current_offset, &o);
+        if (r < 0)
+                return r;
+
+        *ret = le64toh(o->entry.realtime);
+        return 0;
+}
+
+int sd_journal_get_monotonic_usec(sd_journal *j, uint64_t *ret, sd_id128_t *ret_boot_id) {
+        Object *o;
+        JournalFile *f;
+        int r;
+        sd_id128_t id;
+
+        assert(j);
+        assert(ret);
+
+        f = j->current_file;
+        if (!f)
+                return -EADDRNOTAVAIL;
+
+        if (f->current_offset <= 0)
+                return -EADDRNOTAVAIL;
+
+        r = journal_file_move_to_object(f, OBJECT_ENTRY, f->current_offset, &o);
+        if (r < 0)
+                return r;
+
+        if (ret_boot_id)
+                *ret_boot_id = o->entry.boot_id;
+        else {
+                r = sd_id128_get_boot(&id);
+                if (r < 0)
+                        return r;
+
+                if (!sd_id128_equal(id, o->entry.boot_id))
+                        return -ENOENT;
+        }
+
+        *ret = le64toh(o->entry.monotonic);
+        return 0;
+}
+
+int sd_journal_get_data(sd_journal *j, const char *field, const void **data, size_t *size) {
+        JournalFile *f;
+        uint64_t i, n;
+        size_t field_length;
+        int r;
+        Object *o;
+
+        assert(j);
+        assert(field);
+        assert(data);
+        assert(size);
+
+        if (isempty(field) || strchr(field, '='))
+                return -EINVAL;
+
+        f = j->current_file;
+        if (!f)
+                return -EADDRNOTAVAIL;
+
+        if (f->current_offset <= 0)
+                return -EADDRNOTAVAIL;
+
+        r = journal_file_move_to_object(f, OBJECT_ENTRY, f->current_offset, &o);
+        if (r < 0)
+                return r;
+
+        field_length = strlen(field);
+
+        n = journal_file_entry_n_items(o);
+        for (i = 0; i < n; i++) {
+                uint64_t p, l, le_hash;
+                size_t t;
+
+                p = le64toh(o->entry.items[i].object_offset);
+                le_hash = o->entry.items[i].hash;
+                r = journal_file_move_to_object(f, OBJECT_DATA, p, &o);
+                if (r < 0)
+                        return r;
+
+                if (le_hash != o->data.hash)
+                        return -EBADMSG;
+
+                l = le64toh(o->object.size) - offsetof(Object, data.payload);
+
+                if (o->object.flags & OBJECT_COMPRESSED) {
+
+#ifdef HAVE_XZ
+                        if (uncompress_startswith(o->data.payload, l,
+                                                  &f->compress_buffer, &f->compress_buffer_size,
+                                                  field, field_length, '=')) {
+
+                                uint64_t rsize;
+
+                                if (!uncompress_blob(o->data.payload, l,
+                                                     &f->compress_buffer, &f->compress_buffer_size, &rsize))
+                                        return -EBADMSG;
+
+                                *data = f->compress_buffer;
+                                *size = (size_t) rsize;
+
+                                return 0;
+                        }
+#else
+                        return -EPROTONOSUPPORT;
+#endif
+
+                } else if (l >= field_length+1 &&
+                           memcmp(o->data.payload, field, field_length) == 0 &&
+                           o->data.payload[field_length] == '=') {
+
+                        t = (size_t) l;
+
+                        if ((uint64_t) t != l)
+                                return -E2BIG;
+
+                        *data = o->data.payload;
+                        *size = t;
+
+                        return 0;
+                }
+
+                r = journal_file_move_to_object(f, OBJECT_ENTRY, f->current_offset, &o);
+                if (r < 0)
+                        return r;
+        }
+
+        return -ENOENT;
+}
+
+int sd_journal_enumerate_data(sd_journal *j, const void **data, size_t *size) {
+        JournalFile *f;
+        uint64_t p, l, n, le_hash;
+        int r;
+        Object *o;
+        size_t t;
+
+        assert(j);
+        assert(data);
+        assert(size);
+
+        f = j->current_file;
+        if (!f)
+                return -EADDRNOTAVAIL;
+
+        if (f->current_offset <= 0)
+                return -EADDRNOTAVAIL;
+
+        r = journal_file_move_to_object(f, OBJECT_ENTRY, f->current_offset, &o);
+        if (r < 0)
+                return r;
+
+        n = journal_file_entry_n_items(o);
+        if (j->current_field >= n)
+                return 0;
+
+        p = le64toh(o->entry.items[j->current_field].object_offset);
+        le_hash = o->entry.items[j->current_field].hash;
+        r = journal_file_move_to_object(f, OBJECT_DATA, p, &o);
+        if (r < 0)
+                return r;
+
+        if (le_hash != o->data.hash)
+                return -EBADMSG;
+
+        l = le64toh(o->object.size) - offsetof(Object, data.payload);
+        t = (size_t) l;
+
+        /* We can't read objects larger than 4G on a 32bit machine */
+        if ((uint64_t) t != l)
+                return -E2BIG;
+
+        if (o->object.flags & OBJECT_COMPRESSED) {
+#ifdef HAVE_XZ
+                uint64_t rsize;
+
+                if (!uncompress_blob(o->data.payload, l, &f->compress_buffer, &f->compress_buffer_size, &rsize))
+                        return -EBADMSG;
+
+                *data = f->compress_buffer;
+                *size = (size_t) rsize;
+#else
+                return -EPROTONOSUPPORT;
+#endif
+        } else {
+                *data = o->data.payload;
+                *size = t;
+        }
+
+        j->current_field ++;
+
+        return 1;
+}
+
+void sd_journal_restart_data(sd_journal *j) {
+        assert(j);
+
+        j->current_field = 0;
+}
+
+int sd_journal_get_fd(sd_journal *j) {
+        assert(j);
+
+        return j->inotify_fd;
+}
+
+static void process_inotify_event(sd_journal *j, struct inotify_event *e) {
+        char *p;
+        int r;
+
+        assert(j);
+        assert(e);
+
+        /* Is this a subdirectory we watch? */
+        p = hashmap_get(j->inotify_wd_dirs, INT_TO_PTR(e->wd));
+        if (p) {
+
+                if (!(e->mask & IN_ISDIR) && e->len > 0 && endswith(e->name, ".journal")) {
+
+                        /* Event for a journal file */
+
+                        if (e->mask & (IN_CREATE|IN_MOVED_TO|IN_MODIFY|IN_ATTRIB)) {
+                                r = add_file(j, p, NULL, e->name);
+                                if (r < 0)
+                                        log_debug("Failed to add file %s/%s: %s", p, e->name, strerror(-r));
+                        } else if (e->mask & (IN_DELETE|IN_UNMOUNT)) {
+
+                                r = remove_file(j, p, NULL, e->name);
+                                if (r < 0)
+                                        log_debug("Failed to remove file %s/%s: %s", p, e->name, strerror(-r));
+                        }
+
+                } else if (e->len == 0) {
+
+                        /* Event for the directory itself */
+
+                        if (e->mask & (IN_DELETE_SELF|IN_MOVE_SELF|IN_UNMOUNT))
+                                remove_directory_wd(j, e->wd);
+                }
+
+                return;
+        }
+
+        /* Must be the root directory then? */
+        p = hashmap_get(j->inotify_wd_roots, INT_TO_PTR(e->wd));
+        if (p) {
+                sd_id128_t id;
+
+                if (!(e->mask & IN_ISDIR) && e->len > 0 && endswith(e->name, ".journal")) {
+
+                        /* Event for a journal file */
+
+                        if (e->mask & (IN_CREATE|IN_MOVED_TO|IN_MODIFY|IN_ATTRIB)) {
+                                r = add_file(j, p, NULL, e->name);
+                                if (r < 0)
+                                        log_debug("Failed to add file %s/%s: %s", p, e->name, strerror(-r));
+                        } else if (e->mask & (IN_DELETE|IN_UNMOUNT)) {
+
+                                r = remove_file(j, p, NULL, e->name);
+                                if (r < 0)
+                                        log_debug("Failed to remove file %s/%s: %s", p, e->name, strerror(-r));
+                        }
+
+                } else if ((e->mask & IN_ISDIR) && e->len > 0 && sd_id128_from_string(e->name, &id) >= 0) {
+
+                        /* Event for subdirectory */
+
+                        if (e->mask & (IN_CREATE|IN_MOVED_TO|IN_MODIFY|IN_ATTRIB)) {
+
+                                r = add_directory(j, p, e->name);
+                                if (r < 0)
+                                        log_debug("Failed to add directory %s/%s: %s", p, e->name, strerror(-r));
+                        }
+                }
+
+                return;
+        }
+
+        if (e->mask & IN_IGNORED)
+                return;
+
+        log_warning("Unknown inotify event.");
+}
+
+int sd_journal_process(sd_journal *j) {
+        uint8_t buffer[sizeof(struct inotify_event) + FILENAME_MAX];
+
+        assert(j);
+
+        for (;;) {
+                struct inotify_event *e;
+                ssize_t l;
+
+                l = read(j->inotify_fd, buffer, sizeof(buffer));
+                if (l < 0) {
+                        if (errno == EINTR || errno == EAGAIN)
+                                return 0;
+
+                        return -errno;
+                }
+
+                e = (struct inotify_event*) buffer;
+                while (l > 0) {
+                        size_t step;
+
+                        process_inotify_event(j, e);
+
+                        step = sizeof(struct inotify_event) + e->len;
+                        assert(step <= (size_t) l);
+
+                        e = (struct inotify_event*) ((uint8_t*) e + step);
+                        l -= step;
+                }
+        }
+}
+
+int sd_journal_query_unique(sd_journal *j, const char *field) {
+        assert(j);
+        assert(field);
+
+        return -ENOTSUP;
+}
+
+int sd_journal_enumerate_unique(sd_journal *j, const void **data, size_t *l) {
+        assert(j);
+
+        return -ENOTSUP;
+}
+
+void sd_journal_restart_unique(sd_journal *j) {
+        assert(j);
+}