/*-*- 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 Lesser General Public License as published by
  the Free Software Foundation; either version 2.1 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
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public License
  along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/

#include <sys/signalfd.h>
#include <sys/ioctl.h>
#include <linux/sockios.h>
#include <sys/statvfs.h>
#include <sys/mman.h>

#include <libudev.h>
#include <systemd/sd-journal.h>
#include <systemd/sd-messages.h>
#include <systemd/sd-daemon.h>

#ifdef HAVE_LOGIND
#include <systemd/sd-login.h>
#endif

#include "fileio.h"
#include "mkdir.h"
#include "hashmap.h"
#include "journal-file.h"
#include "socket-util.h"
#include "cgroup-util.h"
#include "list.h"
#include "virt.h"
#include "missing.h"
#include "conf-parser.h"
#include "journal-internal.h"
#include "journal-vacuum.h"
#include "journal-authenticate.h"
#include "journald-server.h"
#include "journald-rate-limit.h"
#include "journald-kmsg.h"
#include "journald-syslog.h"
#include "journald-stream.h"
#include "journald-console.h"
#include "journald-native.h"

#ifdef HAVE_ACL
#include <sys/acl.h>
#include <acl/libacl.h>
#include "acl-util.h"
#endif

#ifdef HAVE_SELINUX
#include <selinux/selinux.h>
#endif

#define USER_JOURNALS_MAX 1024

#define DEFAULT_RATE_LIMIT_INTERVAL (10*USEC_PER_SEC)
#define DEFAULT_RATE_LIMIT_BURST 200

#define RECHECK_AVAILABLE_SPACE_USEC (30*USEC_PER_SEC)

static const char* const storage_table[] = {
        [STORAGE_AUTO] = "auto",
        [STORAGE_VOLATILE] = "volatile",
        [STORAGE_PERSISTENT] = "persistent",
        [STORAGE_NONE] = "none"
};

DEFINE_STRING_TABLE_LOOKUP(storage, Storage);
DEFINE_CONFIG_PARSE_ENUM(config_parse_storage, storage, Storage, "Failed to parse storage setting");

static const char* const split_mode_table[] = {
        [SPLIT_NONE] = "none",
        [SPLIT_UID] = "uid",
        [SPLIT_LOGIN] = "login"
};

DEFINE_STRING_TABLE_LOOKUP(split_mode, SplitMode);
DEFINE_CONFIG_PARSE_ENUM(config_parse_split_mode, split_mode, SplitMode, "Failed to parse split mode setting");

static uint64_t available_space(Server *s) {
        char ids[33];
        char _cleanup_free_ *p = NULL;
        const char *f;
        sd_id128_t machine;
        struct statvfs ss;
        uint64_t sum = 0, avail = 0, ss_avail = 0;
        int r;
        DIR _cleanup_closedir_ *d = NULL;
        usec_t ts;
        JournalMetrics *m;

        ts = now(CLOCK_MONOTONIC);

        if (s->cached_available_space_timestamp + RECHECK_AVAILABLE_SPACE_USEC > ts)
                return s->cached_available_space;

        r = sd_id128_get_machine(&machine);
        if (r < 0)
                return 0;

        if (s->system_journal) {
                f = "/var/log/journal/";
                m = &s->system_metrics;
        } else {
                f = "/run/log/journal/";
                m = &s->runtime_metrics;
        }

        assert(m);

        p = strappend(f, sd_id128_to_string(machine, ids));
        if (!p)
                return 0;

        d = opendir(p);
        if (!d)
                return 0;

        if (fstatvfs(dirfd(d), &ss) < 0)
                return 0;

        for (;;) {
                struct stat st;
                struct dirent *de;
                union dirent_storage buf;

                r = readdir_r(d, &buf.de, &de);
                if (r != 0)
                        break;

                if (!de)
                        break;

                if (!endswith(de->d_name, ".journal") &&
                    !endswith(de->d_name, ".journal~"))
                        continue;

                if (fstatat(dirfd(d), de->d_name, &st, AT_SYMLINK_NOFOLLOW) < 0)
                        continue;

                if (!S_ISREG(st.st_mode))
                        continue;

                sum += (uint64_t) st.st_blocks * 512UL;
        }

        avail = sum >= m->max_use ? 0 : m->max_use - sum;

        ss_avail = ss.f_bsize * ss.f_bavail;

        ss_avail = ss_avail < m->keep_free ? 0 : ss_avail - m->keep_free;

        if (ss_avail < avail)
                avail = ss_avail;

        s->cached_available_space = avail;
        s->cached_available_space_timestamp = ts;

        return avail;
}

static void server_read_file_gid(Server *s) {
        const char *adm = "adm";
        int r;

        assert(s);

        if (s->file_gid_valid)
                return;

        r = get_group_creds(&adm, &s->file_gid);
        if (r < 0)
                log_warning("Failed to resolve 'adm' group: %s", strerror(-r));

        /* if we couldn't read the gid, then it will be 0, but that's
         * fine and we shouldn't try to resolve the group again, so
         * let's just pretend it worked right-away. */
        s->file_gid_valid = true;
}

void server_fix_perms(Server *s, JournalFile *f, uid_t uid) {
        int r;
#ifdef HAVE_ACL
        acl_t acl;
        acl_entry_t entry;
        acl_permset_t permset;
#endif

        assert(f);

        server_read_file_gid(s);

        r = fchmod_and_fchown(f->fd, 0640, 0, s->file_gid);
        if (r < 0)
                log_warning("Failed to fix access mode/rights on %s, ignoring: %s", f->path, strerror(-r));

#ifdef HAVE_ACL
        if (uid <= 0)
                return;

        acl = acl_get_fd(f->fd);
        if (!acl) {
                log_warning("Failed to read ACL on %s, ignoring: %m", f->path);
                return;
        }

        r = acl_find_uid(acl, uid, &entry);
        if (r <= 0) {

                if (acl_create_entry(&acl, &entry) < 0 ||
                    acl_set_tag_type(entry, ACL_USER) < 0 ||
                    acl_set_qualifier(entry, &uid) < 0) {
                        log_warning("Failed to patch ACL on %s, ignoring: %m", f->path);
                        goto finish;
                }
        }

        if (acl_get_permset(entry, &permset) < 0 ||
            acl_add_perm(permset, ACL_READ) < 0 ||
            acl_calc_mask(&acl) < 0) {
                log_warning("Failed to patch ACL on %s, ignoring: %m", f->path);
                goto finish;
        }

        if (acl_set_fd(f->fd, acl) < 0)
                log_warning("Failed to set ACL on %s, ignoring: %m", f->path);

finish:
        acl_free(acl);
#endif
}

static JournalFile* find_journal(Server *s, uid_t uid) {
        char *p;
        int r;
        JournalFile *f;
        sd_id128_t machine;

        assert(s);

        /* We split up user logs only on /var, not on /run. If the
         * runtime file is open, we write to it exclusively, in order
         * to guarantee proper order as soon as we flush /run to
         * /var and close the runtime file. */

        if (s->runtime_journal)
                return s->runtime_journal;

        if (uid <= 0)
                return s->system_journal;

        r = sd_id128_get_machine(&machine);
        if (r < 0)
                return s->system_journal;

        f = hashmap_get(s->user_journals, UINT32_TO_PTR(uid));
        if (f)
                return f;

        if (asprintf(&p, "/var/log/journal/" SD_ID128_FORMAT_STR "/user-%lu.journal",
                     SD_ID128_FORMAT_VAL(machine), (unsigned long) uid) < 0)
                return s->system_journal;

        while (hashmap_size(s->user_journals) >= USER_JOURNALS_MAX) {
                /* Too many open? Then let's close one */
                f = hashmap_steal_first(s->user_journals);
                assert(f);
                journal_file_close(f);
        }

        r = journal_file_open_reliably(p, O_RDWR|O_CREAT, 0640, s->compress, s->seal, &s->system_metrics, s->mmap, s->system_journal, &f);
        free(p);

        if (r < 0)
                return s->system_journal;

        server_fix_perms(s, f, uid);

        r = hashmap_put(s->user_journals, UINT32_TO_PTR(uid), f);
        if (r < 0) {
                journal_file_close(f);
                return s->system_journal;
        }

        return f;
}

void server_rotate(Server *s) {
        JournalFile *f;
        void *k;
        Iterator i;
        int r;

        log_debug("Rotating...");

        if (s->runtime_journal) {
                r = journal_file_rotate(&s->runtime_journal, s->compress, false);
                if (r < 0)
                        if (s->runtime_journal)
                                log_error("Failed to rotate %s: %s", s->runtime_journal->path, strerror(-r));
                        else
                                log_error("Failed to create new runtime journal: %s", strerror(-r));
                else
                        server_fix_perms(s, s->runtime_journal, 0);
        }

        if (s->system_journal) {
                r = journal_file_rotate(&s->system_journal, s->compress, s->seal);
                if (r < 0)
                        if (s->system_journal)
                                log_error("Failed to rotate %s: %s", s->system_journal->path, strerror(-r));
                        else
                                log_error("Failed to create new system journal: %s", strerror(-r));

                else
                        server_fix_perms(s, s->system_journal, 0);
        }

        HASHMAP_FOREACH_KEY(f, k, s->user_journals, i) {
                r = journal_file_rotate(&f, s->compress, s->seal);
                if (r < 0)
                        if (f)
                                log_error("Failed to rotate %s: %s", f->path, strerror(-r));
                        else
                                log_error("Failed to create user journal: %s", strerror(-r));
                else {
                        hashmap_replace(s->user_journals, k, f);
                        server_fix_perms(s, f, PTR_TO_UINT32(k));
                }
        }
}

void server_vacuum(Server *s) {
        char *p;
        char ids[33];
        sd_id128_t machine;
        int r;

        log_debug("Vacuuming...");

        s->oldest_file_usec = 0;

        r = sd_id128_get_machine(&machine);
        if (r < 0) {
                log_error("Failed to get machine ID: %s", strerror(-r));
                return;
        }

        sd_id128_to_string(machine, ids);

        if (s->system_journal) {
                p = strappend("/var/log/journal/", ids);
                if (!p) {
                        log_oom();
                        return;
                }

                r = journal_directory_vacuum(p, s->system_metrics.max_use, s->system_metrics.keep_free, s->max_retention_usec, &s->oldest_file_usec);
                if (r < 0 && r != -ENOENT)
                        log_error("Failed to vacuum %s: %s", p, strerror(-r));
                free(p);
        }

        if (s->runtime_journal) {
                p = strappend("/run/log/journal/", ids);
                if (!p) {
                        log_oom();
                        return;
                }

                r = journal_directory_vacuum(p, s->runtime_metrics.max_use, s->runtime_metrics.keep_free, s->max_retention_usec, &s->oldest_file_usec);
                if (r < 0 && r != -ENOENT)
                        log_error("Failed to vacuum %s: %s", p, strerror(-r));
                free(p);
        }

        s->cached_available_space_timestamp = 0;
}

static char *shortened_cgroup_path(pid_t pid) {
        int r;
        char _cleanup_free_ *process_path = NULL, *init_path = NULL;
        char *path;

        assert(pid > 0);

        r = cg_get_by_pid(SYSTEMD_CGROUP_CONTROLLER, pid, &process_path);
        if (r < 0)
                return NULL;

        r = cg_get_by_pid(SYSTEMD_CGROUP_CONTROLLER, 1, &init_path);
        if (r < 0)
                return NULL;

        if (endswith(init_path, "/system"))
                init_path[strlen(init_path) - 7] = 0;
        else if (streq(init_path, "/"))
                init_path[0] = 0;

        if (startswith(process_path, init_path)) {
                path = strdup(process_path + strlen(init_path));
        } else {
                path = process_path;
                process_path = NULL;
        }

        return path;
}

bool shall_try_append_again(JournalFile *f, int r) {

        /* -E2BIG            Hit configured limit
           -EFBIG            Hit fs limit
           -EDQUOT           Quota limit hit
           -ENOSPC           Disk full
           -EHOSTDOWN        Other machine
           -EBUSY            Unclean shutdown
           -EPROTONOSUPPORT  Unsupported feature
           -EBADMSG          Corrupted
           -ENODATA          Truncated
           -ESHUTDOWN        Already archived */

        if (r == -E2BIG || r == -EFBIG || r == -EDQUOT || r == -ENOSPC)
                log_debug("%s: Allocation limit reached, rotating.", f->path);
        else if (r == -EHOSTDOWN)
                log_info("%s: Journal file from other machine, rotating.", f->path);
        else if (r == -EBUSY)
                log_info("%s: Unclean shutdown, rotating.", f->path);
        else if (r == -EPROTONOSUPPORT)
                log_info("%s: Unsupported feature, rotating.", f->path);
        else if (r == -EBADMSG || r == -ENODATA || r == ESHUTDOWN)
                log_warning("%s: Journal file corrupted, rotating.", f->path);
        else
                return false;

        return true;
}

static void write_to_journal(Server *s, uid_t uid, struct iovec *iovec, unsigned n) {
        JournalFile *f;
        bool vacuumed = false;
        int r;

        assert(s);
        assert(iovec);
        assert(n > 0);

        f = find_journal(s, uid);
        if (!f)
                return;

        if (journal_file_rotate_suggested(f, s->max_file_usec)) {
                log_debug("%s: Journal header limits reached or header out-of-date, rotating.", f->path);
                server_rotate(s);
                server_vacuum(s);
                vacuumed = true;

                f = find_journal(s, uid);
                if (!f)
                        return;
        }

        r = journal_file_append_entry(f, NULL, iovec, n, &s->seqnum, NULL, NULL);
        if (r >= 0)
                return;

        if (vacuumed || !shall_try_append_again(f, r)) {
                log_error("Failed to write entry, ignoring: %s", strerror(-r));
                return;
        }

        server_rotate(s);
        server_vacuum(s);

        f = find_journal(s, uid);
        if (!f)
                return;

        log_debug("Retrying write.");
        r = journal_file_append_entry(f, NULL, iovec, n, &s->seqnum, NULL, NULL);
        if (r < 0)
                log_error("Failed to write entry, ignoring: %s", strerror(-r));
}

static void dispatch_message_real(
                Server *s,
                struct iovec *iovec, unsigned n, unsigned m,
                struct ucred *ucred,
                struct timeval *tv,
                const char *label, size_t label_len,
                const char *unit_id) {

        char _cleanup_free_ *pid = NULL, *uid = NULL, *gid = NULL,
                *source_time = NULL, *boot_id = NULL, *machine_id = NULL,
                *comm = NULL, *cmdline = NULL, *hostname = NULL,
                *audit_session = NULL, *audit_loginuid = NULL,
                *exe = NULL, *cgroup = NULL, *session = NULL,
                *owner_uid = NULL, *unit = NULL, *selinux_context = NULL;

        char idbuf[33];
        sd_id128_t id;
        int r;
        char *t;
        uid_t realuid = 0, owner = 0, journal_uid;
        bool owner_valid = false;

        assert(s);
        assert(iovec);
        assert(n > 0);
        assert(n + N_IOVEC_META_FIELDS <= m);

        if (ucred) {
                uint32_t audit;
                uid_t loginuid;

                realuid = ucred->uid;

                if (asprintf(&pid, "_PID=%lu", (unsigned long) ucred->pid) >= 0)
                        IOVEC_SET_STRING(iovec[n++], pid);

                if (asprintf(&uid, "_UID=%lu", (unsigned long) ucred->uid) >= 0)
                        IOVEC_SET_STRING(iovec[n++], uid);

                if (asprintf(&gid, "_GID=%lu", (unsigned long) ucred->gid) >= 0)
                        IOVEC_SET_STRING(iovec[n++], gid);

                r = get_process_comm(ucred->pid, &t);
                if (r >= 0) {
                        comm = strappend("_COMM=", t);
                        free(t);

                        if (comm)
                                IOVEC_SET_STRING(iovec[n++], comm);
                }

                r = get_process_exe(ucred->pid, &t);
                if (r >= 0) {
                        exe = strappend("_EXE=", t);
                        free(t);

                        if (exe)
                                IOVEC_SET_STRING(iovec[n++], exe);
                }

                r = get_process_cmdline(ucred->pid, 0, false, &t);
                if (r >= 0) {
                        cmdline = strappend("_CMDLINE=", t);
                        free(t);

                        if (cmdline)
                                IOVEC_SET_STRING(iovec[n++], cmdline);
                }

                r = audit_session_from_pid(ucred->pid, &audit);
                if (r >= 0)
                        if (asprintf(&audit_session, "_AUDIT_SESSION=%lu", (unsigned long) audit) >= 0)
                                IOVEC_SET_STRING(iovec[n++], audit_session);

                r = audit_loginuid_from_pid(ucred->pid, &loginuid);
                if (r >= 0)
                        if (asprintf(&audit_loginuid, "_AUDIT_LOGINUID=%lu", (unsigned long) loginuid) >= 0)
                                IOVEC_SET_STRING(iovec[n++], audit_loginuid);

                t = shortened_cgroup_path(ucred->pid);
                if (t) {
                        cgroup = strappend("_SYSTEMD_CGROUP=", t);
                        free(t);

                        if (cgroup)
                                IOVEC_SET_STRING(iovec[n++], cgroup);
                }

#ifdef HAVE_LOGIND
                if (sd_pid_get_session(ucred->pid, &t) >= 0) {
                        session = strappend("_SYSTEMD_SESSION=", t);
                        free(t);

                        if (session)
                                IOVEC_SET_STRING(iovec[n++], session);
                }

                if (sd_pid_get_owner_uid(ucred->uid, &owner) >= 0) {
                        owner_valid = true;
                        if (asprintf(&owner_uid, "_SYSTEMD_OWNER_UID=%lu", (unsigned long) owner) >= 0)
                                IOVEC_SET_STRING(iovec[n++], owner_uid);
                }
#endif

                if (cg_pid_get_unit(ucred->pid, &t) >= 0) {
                        unit = strappend("_SYSTEMD_UNIT=", t);
                        free(t);
                } else if (cg_pid_get_user_unit(ucred->pid, &t) >= 0) {
                        unit = strappend("_SYSTEMD_USER_UNIT=", t);
                        free(t);
                } else if (unit_id) {
                        if (session)
                                unit = strappend("_SYSTEMD_USER_UNIT=", unit_id);
                        else
                                unit = strappend("_SYSTEMD_UNIT=", unit_id);
                }

                if (unit)
                        IOVEC_SET_STRING(iovec[n++], unit);

#ifdef HAVE_SELINUX
                if (label) {
                        selinux_context = malloc(sizeof("_SELINUX_CONTEXT=") + label_len);
                        if (selinux_context) {
                                memcpy(selinux_context, "_SELINUX_CONTEXT=", sizeof("_SELINUX_CONTEXT=")-1);
                                memcpy(selinux_context+sizeof("_SELINUX_CONTEXT=")-1, label, label_len);
                                selinux_context[sizeof("_SELINUX_CONTEXT=")-1+label_len] = 0;
                                IOVEC_SET_STRING(iovec[n++], selinux_context);
                        }
                } else {
                        security_context_t con;

                        if (getpidcon(ucred->pid, &con) >= 0) {
                                selinux_context = strappend("_SELINUX_CONTEXT=", con);
                                if (selinux_context)
                                        IOVEC_SET_STRING(iovec[n++], selinux_context);

                                freecon(con);
                        }
                }
#endif
        }

        if (tv) {
                if (asprintf(&source_time, "_SOURCE_REALTIME_TIMESTAMP=%llu",
                             (unsigned long long) timeval_load(tv)) >= 0)
                        IOVEC_SET_STRING(iovec[n++], source_time);
        }

        /* Note that strictly speaking storing the boot id here is
         * redundant since the entry includes this in-line
         * anyway. However, we need this indexed, too. */
        r = sd_id128_get_boot(&id);
        if (r >= 0)
                if (asprintf(&boot_id, "_BOOT_ID=%s", sd_id128_to_string(id, idbuf)) >= 0)
                        IOVEC_SET_STRING(iovec[n++], boot_id);

        r = sd_id128_get_machine(&id);
        if (r >= 0)
                if (asprintf(&machine_id, "_MACHINE_ID=%s", sd_id128_to_string(id, idbuf)) >= 0)
                        IOVEC_SET_STRING(iovec[n++], machine_id);

        t = gethostname_malloc();
        if (t) {
                hostname = strappend("_HOSTNAME=", t);
                free(t);
                if (hostname)
                        IOVEC_SET_STRING(iovec[n++], hostname);
        }

        assert(n <= m);

        if (s->split_mode == SPLIT_UID && realuid > 0)
                /* Split up strictly by any UID */
                journal_uid = realuid;
        else if (s->split_mode == SPLIT_LOGIN && realuid > 0 && owner_valid && owner > 0)
                /* Split up by login UIDs, this avoids creation of
                 * individual journals for system UIDs.  We do this
                 * only if the realuid is not root, in order not to
                 * accidentally leak privileged information to the
                 * user that is logged by a privileged process that is
                 * part of an unprivileged session.*/
                journal_uid = owner;
        else
                journal_uid = 0;

        write_to_journal(s, journal_uid, iovec, n);
}

void server_driver_message(Server *s, sd_id128_t message_id, const char *format, ...) {
        char mid[11 + 32 + 1];
        char buffer[16 + LINE_MAX + 1];
        struct iovec iovec[N_IOVEC_META_FIELDS + 4];
        int n = 0;
        va_list ap;
        struct ucred ucred;

        assert(s);
        assert(format);

        IOVEC_SET_STRING(iovec[n++], "PRIORITY=6");
        IOVEC_SET_STRING(iovec[n++], "_TRANSPORT=driver");

        memcpy(buffer, "MESSAGE=", 8);
        va_start(ap, format);
        vsnprintf(buffer + 8, sizeof(buffer) - 8, format, ap);
        va_end(ap);
        char_array_0(buffer);
        IOVEC_SET_STRING(iovec[n++], buffer);

        if (!sd_id128_equal(message_id, SD_ID128_NULL)) {
                snprintf(mid, sizeof(mid), MESSAGE_ID(message_id));
                char_array_0(mid);
                IOVEC_SET_STRING(iovec[n++], mid);
        }

        zero(ucred);
        ucred.pid = getpid();
        ucred.uid = getuid();
        ucred.gid = getgid();

        dispatch_message_real(s, iovec, n, ELEMENTSOF(iovec), &ucred, NULL, NULL, 0, NULL);
}

void server_dispatch_message(
                Server *s,
                struct iovec *iovec, unsigned n, unsigned m,
                struct ucred *ucred,
                struct timeval *tv,
                const char *label, size_t label_len,
                const char *unit_id,
                int priority) {

        int rl;
        char _cleanup_free_ *path = NULL;
        char *c;

        assert(s);
        assert(iovec || n == 0);

        if (n == 0)
                return;

        if (LOG_PRI(priority) > s->max_level_store)
                return;

        if (!ucred)
                goto finish;

        path = shortened_cgroup_path(ucred->pid);
        if (!path)
                goto finish;

        /* example: /user/lennart/3/foobar
         *          /system/dbus.service/foobar
         *
         * So let's cut of everything past the third /, since that is
         * where user directories start */

        c = strchr(path, '/');
        if (c) {
                c = strchr(c+1, '/');
                if (c) {
                        c = strchr(c+1, '/');
                        if (c)
                                *c = 0;
                }
        }

        rl = journal_rate_limit_test(s->rate_limit, path,
                                     priority & LOG_PRIMASK, available_space(s));

        if (rl == 0)
                return;

        /* Write a suppression message if we suppressed something */
        if (rl > 1)
                server_driver_message(s, SD_MESSAGE_JOURNAL_DROPPED,
                                      "Suppressed %u messages from %s", rl - 1, path);

finish:
        dispatch_message_real(s, iovec, n, m, ucred, tv, label, label_len, unit_id);
}


static int system_journal_open(Server *s) {
        int r;
        char *fn;
        sd_id128_t machine;
        char ids[33];

        r = sd_id128_get_machine(&machine);
        if (r < 0)
                return r;

        sd_id128_to_string(machine, ids);

        if (!s->system_journal &&
            (s->storage == STORAGE_PERSISTENT || s->storage == STORAGE_AUTO) &&
            access("/run/systemd/journal/flushed", F_OK) >= 0) {

                /* If in auto mode: first try to create the machine
                 * path, but not the prefix.
                 *
                 * If in persistent mode: create /var/log/journal and
                 * the machine path */

                if (s->storage == STORAGE_PERSISTENT)
                        (void) mkdir("/var/log/journal/", 0755);

                fn = strappend("/var/log/journal/", ids);
                if (!fn)
                        return -ENOMEM;

                (void) mkdir(fn, 0755);
                free(fn);

                fn = strjoin("/var/log/journal/", ids, "/system.journal", NULL);
                if (!fn)
                        return -ENOMEM;

                r = journal_file_open_reliably(fn, O_RDWR|O_CREAT, 0640, s->compress, s->seal, &s->system_metrics, s->mmap, NULL, &s->system_journal);
                free(fn);

                if (r >= 0) {
                        char fb[FORMAT_BYTES_MAX];

                        server_fix_perms(s, s->system_journal, 0);
                        server_driver_message(s, SD_ID128_NULL, "Allowing system journal files to grow to %s.",
                                              format_bytes(fb, sizeof(fb), s->system_metrics.max_use));

                } else if (r < 0) {

                        if (r != -ENOENT && r != -EROFS)
                                log_warning("Failed to open system journal: %s", strerror(-r));

                        r = 0;
                }
        }

        if (!s->runtime_journal &&
            (s->storage != STORAGE_NONE)) {

                fn = strjoin("/run/log/journal/", ids, "/system.journal", NULL);
                if (!fn)
                        return -ENOMEM;

                if (s->system_journal) {

                        /* Try to open the runtime journal, but only
                         * if it already exists, so that we can flush
                         * it into the system journal */

                        r = journal_file_open(fn, O_RDWR, 0640, s->compress, false, &s->runtime_metrics, s->mmap, NULL, &s->runtime_journal);
                        free(fn);

                        if (r < 0) {
                                if (r != -ENOENT)
                                        log_warning("Failed to open runtime journal: %s", strerror(-r));

                                r = 0;
                        }

                } else {

                        /* OK, we really need the runtime journal, so create
                         * it if necessary. */

                        (void) mkdir_parents(fn, 0755);
                        r = journal_file_open_reliably(fn, O_RDWR|O_CREAT, 0640, s->compress, false, &s->runtime_metrics, s->mmap, NULL, &s->runtime_journal);
                        free(fn);

                        if (r < 0) {
                                log_error("Failed to open runtime journal: %s", strerror(-r));
                                return r;
                        }
                }

                if (s->runtime_journal) {
                        char fb[FORMAT_BYTES_MAX];

                        server_fix_perms(s, s->runtime_journal, 0);
                        server_driver_message(s, SD_ID128_NULL, "Allowing runtime journal files to grow to %s.",
                                              format_bytes(fb, sizeof(fb), s->runtime_metrics.max_use));
                }
        }

        return r;
}

int server_flush_to_var(Server *s) {
        int r;
        sd_id128_t machine;
        sd_journal *j = NULL;

        assert(s);

        if (s->storage != STORAGE_AUTO &&
            s->storage != STORAGE_PERSISTENT)
                return 0;

        if (!s->runtime_journal)
                return 0;

        system_journal_open(s);

        if (!s->system_journal)
                return 0;

        log_debug("Flushing to /var...");

        r = sd_id128_get_machine(&machine);
        if (r < 0) {
                log_error("Failed to get machine id: %s", strerror(-r));
                return r;
        }

        r = sd_journal_open(&j, SD_JOURNAL_RUNTIME_ONLY);
        if (r < 0) {
                log_error("Failed to read runtime journal: %s", strerror(-r));
                return r;
        }

        sd_journal_set_data_threshold(j, 0);

        SD_JOURNAL_FOREACH(j) {
                Object *o = NULL;
                JournalFile *f;

                f = j->current_file;
                assert(f && f->current_offset > 0);

                r = journal_file_move_to_object(f, OBJECT_ENTRY, f->current_offset, &o);
                if (r < 0) {
                        log_error("Can't read entry: %s", strerror(-r));
                        goto finish;
                }

                r = journal_file_copy_entry(f, s->system_journal, o, f->current_offset, NULL, NULL, NULL);
                if (r >= 0)
                        continue;

                if (!shall_try_append_again(s->system_journal, r)) {
                        log_error("Can't write entry: %s", strerror(-r));
                        goto finish;
                }

                server_rotate(s);
                server_vacuum(s);

                log_debug("Retrying write.");
                r = journal_file_copy_entry(f, s->system_journal, o, f->current_offset, NULL, NULL, NULL);
                if (r < 0) {
                        log_error("Can't write entry: %s", strerror(-r));
                        goto finish;
                }
        }

finish:
        journal_file_post_change(s->system_journal);

        journal_file_close(s->runtime_journal);
        s->runtime_journal = NULL;

        if (r >= 0)
                rm_rf("/run/log/journal", false, true, false);

        if (j)
                sd_journal_close(j);

        return r;
}

int process_event(Server *s, struct epoll_event *ev) {
        assert(s);
        assert(ev);

        if (ev->data.fd == s->signal_fd) {
                struct signalfd_siginfo sfsi;
                ssize_t n;

                if (ev->events != EPOLLIN) {
                        log_error("Got invalid event from epoll.");
                        return -EIO;
                }

                n = read(s->signal_fd, &sfsi, sizeof(sfsi));
                if (n != sizeof(sfsi)) {

                        if (n >= 0)
                                return -EIO;

                        if (errno == EINTR || errno == EAGAIN)
                                return 1;

                        return -errno;
                }

                log_info("Received SIG%s", signal_to_string(sfsi.ssi_signo));

                if (sfsi.ssi_signo == SIGUSR1) {
                        touch("/run/systemd/journal/flushed");
                        server_flush_to_var(s);
                        return 1;
                }

                if (sfsi.ssi_signo == SIGUSR2) {
                        server_rotate(s);
                        server_vacuum(s);
                        return 1;
                }

                return 0;

        } else if (ev->data.fd == s->dev_kmsg_fd) {
                int r;

                if (ev->events != EPOLLIN) {
                        log_error("Got invalid event from epoll.");
                        return -EIO;
                }

                r = server_read_dev_kmsg(s);
                if (r < 0)
                        return r;

                return 1;

        } else if (ev->data.fd == s->native_fd ||
                   ev->data.fd == s->syslog_fd) {

                if (ev->events != EPOLLIN) {
                        log_error("Got invalid event from epoll.");
                        return -EIO;
                }

                for (;;) {
                        struct msghdr msghdr;
                        struct iovec iovec;
                        struct ucred *ucred = NULL;
                        struct timeval *tv = NULL;
                        struct cmsghdr *cmsg;
                        char *label = NULL;
                        size_t label_len = 0;
                        union {
                                struct cmsghdr cmsghdr;

                                /* We use NAME_MAX space for the
                                 * SELinux label here. The kernel
                                 * currently enforces no limit, but
                                 * according to suggestions from the
                                 * SELinux people this will change and
                                 * it will probably be identical to
                                 * NAME_MAX. For now we use that, but
                                 * this should be updated one day when
                                 * the final limit is known.*/
                                uint8_t buf[CMSG_SPACE(sizeof(struct ucred)) +
                                            CMSG_SPACE(sizeof(struct timeval)) +
                                            CMSG_SPACE(sizeof(int)) + /* fd */
                                            CMSG_SPACE(NAME_MAX)]; /* selinux label */
                        } control;
                        ssize_t n;
                        int v;
                        int *fds = NULL;
                        unsigned n_fds = 0;

                        if (ioctl(ev->data.fd, SIOCINQ, &v) < 0) {
                                log_error("SIOCINQ failed: %m");
                                return -errno;
                        }

                        if (s->buffer_size < (size_t) v) {
                                void *b;
                                size_t l;

                                l = MAX(LINE_MAX + (size_t) v, s->buffer_size * 2);
                                b = realloc(s->buffer, l+1);

                                if (!b) {
                                        log_error("Couldn't increase buffer.");
                                        return -ENOMEM;
                                }

                                s->buffer_size = l;
                                s->buffer = b;
                        }

                        zero(iovec);
                        iovec.iov_base = s->buffer;
                        iovec.iov_len = s->buffer_size;

                        zero(control);
                        zero(msghdr);
                        msghdr.msg_iov = &iovec;
                        msghdr.msg_iovlen = 1;
                        msghdr.msg_control = &control;
                        msghdr.msg_controllen = sizeof(control);

                        n = recvmsg(ev->data.fd, &msghdr, MSG_DONTWAIT|MSG_CMSG_CLOEXEC);
                        if (n < 0) {

                                if (errno == EINTR || errno == EAGAIN)
                                        return 1;

                                log_error("recvmsg() failed: %m");
                                return -errno;
                        }

                        for (cmsg = CMSG_FIRSTHDR(&msghdr); cmsg; cmsg = CMSG_NXTHDR(&msghdr, cmsg)) {

                                if (cmsg->cmsg_level == SOL_SOCKET &&
                                    cmsg->cmsg_type == SCM_CREDENTIALS &&
                                    cmsg->cmsg_len == CMSG_LEN(sizeof(struct ucred)))
                                        ucred = (struct ucred*) CMSG_DATA(cmsg);
                                else if (cmsg->cmsg_level == SOL_SOCKET &&
                                         cmsg->cmsg_type == SCM_SECURITY) {
                                        label = (char*) CMSG_DATA(cmsg);
                                        label_len = cmsg->cmsg_len - CMSG_LEN(0);
                                } else if (cmsg->cmsg_level == SOL_SOCKET &&
                                         cmsg->cmsg_type == SO_TIMESTAMP &&
                                         cmsg->cmsg_len == CMSG_LEN(sizeof(struct timeval)))
                                        tv = (struct timeval*) CMSG_DATA(cmsg);
                                else if (cmsg->cmsg_level == SOL_SOCKET &&
                                         cmsg->cmsg_type == SCM_RIGHTS) {
                                        fds = (int*) CMSG_DATA(cmsg);
                                        n_fds = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int);
                                }
                        }

                        if (ev->data.fd == s->syslog_fd) {
                                char *e;

                                if (n > 0 && n_fds == 0) {
                                        e = memchr(s->buffer, '\n', n);
                                        if (e)
                                                *e = 0;
                                        else
                                                s->buffer[n] = 0;

                                        server_process_syslog_message(s, strstrip(s->buffer), ucred, tv, label, label_len);
                                } else if (n_fds > 0)
                                        log_warning("Got file descriptors via syslog socket. Ignoring.");

                        } else {
                                if (n > 0 && n_fds == 0)
                                        server_process_native_message(s, s->buffer, n, ucred, tv, label, label_len);
                                else if (n == 0 && n_fds == 1)
                                        server_process_native_file(s, fds[0], ucred, tv, label, label_len);
                                else if (n_fds > 0)
                                        log_warning("Got too many file descriptors via native socket. Ignoring.");
                        }

                        close_many(fds, n_fds);
                }

                return 1;

        } else if (ev->data.fd == s->stdout_fd) {

                if (ev->events != EPOLLIN) {
                        log_error("Got invalid event from epoll.");
                        return -EIO;
                }

                stdout_stream_new(s);
                return 1;

        } else {
                StdoutStream *stream;

                if ((ev->events|EPOLLIN|EPOLLHUP) != (EPOLLIN|EPOLLHUP)) {
                        log_error("Got invalid event from epoll.");
                        return -EIO;
                }

                /* If it is none of the well-known fds, it must be an
                 * stdout stream fd. Note that this is a bit ugly here
                 * (since we rely that none of the well-known fds
                 * could be interpreted as pointer), but nonetheless
                 * safe, since the well-known fds would never get an
                 * fd > 4096, i.e. beyond the first memory page */

                stream = ev->data.ptr;

                if (stdout_stream_process(stream) <= 0)
                        stdout_stream_free(stream);

                return 1;
        }

        log_error("Unknown event.");
        return 0;
}

static int open_signalfd(Server *s) {
        sigset_t mask;
        struct epoll_event ev;

        assert(s);

        assert_se(sigemptyset(&mask) == 0);
        sigset_add_many(&mask, SIGINT, SIGTERM, SIGUSR1, SIGUSR2, -1);
        assert_se(sigprocmask(SIG_SETMASK, &mask, NULL) == 0);

        s->signal_fd = signalfd(-1, &mask, SFD_NONBLOCK|SFD_CLOEXEC);
        if (s->signal_fd < 0) {
                log_error("signalfd(): %m");
                return -errno;
        }

        zero(ev);
        ev.events = EPOLLIN;
        ev.data.fd = s->signal_fd;

        if (epoll_ctl(s->epoll_fd, EPOLL_CTL_ADD, s->signal_fd, &ev) < 0) {
                log_error("epoll_ctl(): %m");
                return -errno;
        }

        return 0;
}

static int server_parse_proc_cmdline(Server *s) {
        char _cleanup_free_ *line = NULL;
        char *w, *state;
        int r;
        size_t l;

        if (detect_container(NULL) > 0)
                return 0;

        r = read_one_line_file("/proc/cmdline", &line);
        if (r < 0) {
                log_warning("Failed to read /proc/cmdline, ignoring: %s", strerror(-r));
                return 0;
        }

        FOREACH_WORD_QUOTED(w, l, line, state) {
                char _cleanup_free_ *word;

                word = strndup(w, l);
                if (!word)
                        return -ENOMEM;

                if (startswith(word, "systemd.journald.forward_to_syslog=")) {
                        r = parse_boolean(word + 35);
                        if (r < 0)
                                log_warning("Failed to parse forward to syslog switch %s. Ignoring.", word + 35);
                        else
                                s->forward_to_syslog = r;
                } else if (startswith(word, "systemd.journald.forward_to_kmsg=")) {
                        r = parse_boolean(word + 33);
                        if (r < 0)
                                log_warning("Failed to parse forward to kmsg switch %s. Ignoring.", word + 33);
                        else
                                s->forward_to_kmsg = r;
                } else if (startswith(word, "systemd.journald.forward_to_console=")) {
                        r = parse_boolean(word + 36);
                        if (r < 0)
                                log_warning("Failed to parse forward to console switch %s. Ignoring.", word + 36);
                        else
                                s->forward_to_console = r;
                } else if (startswith(word, "systemd.journald"))
                        log_warning("Invalid systemd.journald parameter. Ignoring.");
        }

        return 0;
}

static int server_parse_config_file(Server *s) {
        static const char *fn = "/etc/systemd/journald.conf";
        FILE _cleanup_fclose_ *f = NULL;
        int r;

        assert(s);

        f = fopen(fn, "re");
        if (!f) {
                if (errno == ENOENT)
                        return 0;

                log_warning("Failed to open configuration file %s: %m", fn);
                return -errno;
        }

        r = config_parse(fn, f, "Journal\0", config_item_perf_lookup,
                         (void*) journald_gperf_lookup, false, s);
        if (r < 0)
                log_warning("Failed to parse configuration file: %s", strerror(-r));

        return r;
}

int server_init(Server *s) {
        int n, r, fd;

        assert(s);

        zero(*s);
        s->syslog_fd = s->native_fd = s->stdout_fd = s->signal_fd = s->epoll_fd = s->dev_kmsg_fd = -1;
        s->compress = true;
        s->seal = true;

        s->rate_limit_interval = DEFAULT_RATE_LIMIT_INTERVAL;
        s->rate_limit_burst = DEFAULT_RATE_LIMIT_BURST;

        s->forward_to_syslog = true;

        s->max_level_store = LOG_DEBUG;
        s->max_level_syslog = LOG_DEBUG;
        s->max_level_kmsg = LOG_NOTICE;
        s->max_level_console = LOG_INFO;

        memset(&s->system_metrics, 0xFF, sizeof(s->system_metrics));
        memset(&s->runtime_metrics, 0xFF, sizeof(s->runtime_metrics));

        server_parse_config_file(s);
        server_parse_proc_cmdline(s);
        if (!!s->rate_limit_interval ^ !!s->rate_limit_burst) {
                log_debug("Setting both rate limit interval and burst from %llu,%u to 0,0",
                          (long long unsigned) s->rate_limit_interval,
                          s->rate_limit_burst);
                s->rate_limit_interval = s->rate_limit_burst = 0;
        }

        mkdir_p("/run/systemd/journal", 0755);

        s->user_journals = hashmap_new(trivial_hash_func, trivial_compare_func);
        if (!s->user_journals)
                return log_oom();

        s->mmap = mmap_cache_new();
        if (!s->mmap)
                return log_oom();

        s->epoll_fd = epoll_create1(EPOLL_CLOEXEC);
        if (s->epoll_fd < 0) {
                log_error("Failed to create epoll object: %m");
                return -errno;
        }

        n = sd_listen_fds(true);
        if (n < 0) {
                log_error("Failed to read listening file descriptors from environment: %s", strerror(-n));
                return n;
        }

        for (fd = SD_LISTEN_FDS_START; fd < SD_LISTEN_FDS_START + n; fd++) {

                if (sd_is_socket_unix(fd, SOCK_DGRAM, -1, "/run/systemd/journal/socket", 0) > 0) {

                        if (s->native_fd >= 0) {
                                log_error("Too many native sockets passed.");
                                return -EINVAL;
                        }

                        s->native_fd = fd;

                } else if (sd_is_socket_unix(fd, SOCK_STREAM, 1, "/run/systemd/journal/stdout", 0) > 0) {

                        if (s->stdout_fd >= 0) {
                                log_error("Too many stdout sockets passed.");
                                return -EINVAL;
                        }

                        s->stdout_fd = fd;

                } else if (sd_is_socket_unix(fd, SOCK_DGRAM, -1, "/dev/log", 0) > 0) {

                        if (s->syslog_fd >= 0) {
                                log_error("Too many /dev/log sockets passed.");
                                return -EINVAL;
                        }

                        s->syslog_fd = fd;

                } else {
                        log_error("Unknown socket passed.");
                        return -EINVAL;
                }
        }

        r = server_open_syslog_socket(s);
        if (r < 0)
                return r;

        r = server_open_native_socket(s);
        if (r < 0)
                return r;

        r = server_open_stdout_socket(s);
        if (r < 0)
                return r;

        r = server_open_dev_kmsg(s);
        if (r < 0)
                return r;

        r = server_open_kernel_seqnum(s);
        if (r < 0)
                return r;

        r = open_signalfd(s);
        if (r < 0)
                return r;

        s->udev = udev_new();
        if (!s->udev)
                return -ENOMEM;

        s->rate_limit = journal_rate_limit_new(s->rate_limit_interval,
                                               s->rate_limit_burst);
        if (!s->rate_limit)
                return -ENOMEM;

        r = system_journal_open(s);
        if (r < 0)
                return r;

        return 0;
}

void server_maybe_append_tags(Server *s) {
#ifdef HAVE_GCRYPT
        JournalFile *f;
        Iterator i;
        usec_t n;

        n = now(CLOCK_REALTIME);

        if (s->system_journal)
                journal_file_maybe_append_tag(s->system_journal, n);

        HASHMAP_FOREACH(f, s->user_journals, i)
                journal_file_maybe_append_tag(f, n);
#endif
}

void server_done(Server *s) {
        JournalFile *f;
        assert(s);

        while (s->stdout_streams)
                stdout_stream_free(s->stdout_streams);

        if (s->system_journal)
                journal_file_close(s->system_journal);

        if (s->runtime_journal)
                journal_file_close(s->runtime_journal);

        while ((f = hashmap_steal_first(s->user_journals)))
                journal_file_close(f);

        hashmap_free(s->user_journals);

        if (s->epoll_fd >= 0)
                close_nointr_nofail(s->epoll_fd);

        if (s->signal_fd >= 0)
                close_nointr_nofail(s->signal_fd);

        if (s->syslog_fd >= 0)
                close_nointr_nofail(s->syslog_fd);

        if (s->native_fd >= 0)
                close_nointr_nofail(s->native_fd);

        if (s->stdout_fd >= 0)
                close_nointr_nofail(s->stdout_fd);

        if (s->dev_kmsg_fd >= 0)
                close_nointr_nofail(s->dev_kmsg_fd);

        if (s->rate_limit)
                journal_rate_limit_free(s->rate_limit);

        if (s->kernel_seqnum)
                munmap(s->kernel_seqnum, sizeof(uint64_t));

        free(s->buffer);
        free(s->tty_path);

        if (s->mmap)
                mmap_cache_unref(s->mmap);

        if (s->udev)
                udev_unref(s->udev);
}