Systemd/src/journal/journald-server.h
Lennart Poettering 4b58153dd2 core: add "invocation ID" concept to service manager
This adds a new invocation ID concept to the service manager. The invocation ID
identifies each runtime cycle of a unit uniquely. A new randomized 128bit ID is
generated each time a unit moves from and inactive to an activating or active
state.

The primary usecase for this concept is to connect the runtime data PID 1
maintains about a service with the offline data the journal stores about it.
Previously we'd use the unit name plus start/stop times, which however is
highly racy since the journal will generally process log data after the service
already ended.

The "invocation ID" kinda matches the "boot ID" concept of the Linux kernel,
except that it applies to an individual unit instead of the whole system.

The invocation ID is passed to the activated processes as environment variable.
It is additionally stored as extended attribute on the cgroup of the unit. The
latter is used by journald to automatically retrieve it for each log logged
message and attach it to the log entry. The environment variable is very easily
accessible, even for unprivileged services. OTOH the extended attribute is only
accessible to privileged processes (this is because cgroupfs only supports the
"trusted." xattr namespace, not "user."). The environment variable may be
altered by services, the extended attribute may not be, hence is the better
choice for the journal.

Note that reading the invocation ID off the extended attribute from journald is
racy, similar to the way reading the unit name for a logging process is.

This patch adds APIs to read the invocation ID to sd-id128:
sd_id128_get_invocation() may be used in a similar fashion to
sd_id128_get_boot().

PID1's own logging is updated to always include the invocation ID when it logs
information about a unit.

A new bus call GetUnitByInvocationID() is added that allows retrieving a bus
path to a unit by its invocation ID. The bus path is built using the invocation
ID, thus providing a path for referring to a unit that is valid only for the
current runtime cycleof it.

Outlook for the future: should the kernel eventually allow passing of cgroup
information along AF_UNIX/SOCK_DGRAM messages via a unique cgroup id, then we
can alter the invocation ID to be generated as hash from that rather than
entirely randomly. This way we can derive the invocation race-freely from the
messages.
2016-10-07 20:14:38 +02:00

187 lines
5.6 KiB
C

#pragma once
/***
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 <stdbool.h>
#include <sys/types.h>
#include "sd-event.h"
typedef struct Server Server;
#include "hashmap.h"
#include "journal-file.h"
#include "journald-rate-limit.h"
#include "journald-stream.h"
#include "list.h"
typedef enum Storage {
STORAGE_AUTO,
STORAGE_VOLATILE,
STORAGE_PERSISTENT,
STORAGE_NONE,
_STORAGE_MAX,
_STORAGE_INVALID = -1
} Storage;
typedef enum SplitMode {
SPLIT_UID,
SPLIT_LOGIN, /* deprecated */
SPLIT_NONE,
_SPLIT_MAX,
_SPLIT_INVALID = -1
} SplitMode;
struct Server {
int syslog_fd;
int native_fd;
int stdout_fd;
int dev_kmsg_fd;
int audit_fd;
int hostname_fd;
int notify_fd;
sd_event *event;
sd_event_source *syslog_event_source;
sd_event_source *native_event_source;
sd_event_source *stdout_event_source;
sd_event_source *dev_kmsg_event_source;
sd_event_source *audit_event_source;
sd_event_source *sync_event_source;
sd_event_source *sigusr1_event_source;
sd_event_source *sigusr2_event_source;
sd_event_source *sigterm_event_source;
sd_event_source *sigint_event_source;
sd_event_source *sigrtmin1_event_source;
sd_event_source *hostname_event_source;
sd_event_source *notify_event_source;
sd_event_source *watchdog_event_source;
JournalFile *runtime_journal;
JournalFile *system_journal;
OrderedHashmap *user_journals;
uint64_t seqnum;
char *buffer;
size_t buffer_size;
JournalRateLimit *rate_limit;
usec_t sync_interval_usec;
usec_t rate_limit_interval;
unsigned rate_limit_burst;
JournalMetrics runtime_metrics;
JournalMetrics system_metrics;
bool compress;
bool seal;
bool forward_to_kmsg;
bool forward_to_syslog;
bool forward_to_console;
bool forward_to_wall;
unsigned n_forward_syslog_missed;
usec_t last_warn_forward_syslog_missed;
uint64_t cached_space_available;
uint64_t cached_space_limit;
usec_t cached_space_timestamp;
uint64_t var_available_timestamp;
usec_t max_retention_usec;
usec_t max_file_usec;
usec_t oldest_file_usec;
LIST_HEAD(StdoutStream, stdout_streams);
LIST_HEAD(StdoutStream, stdout_streams_notify_queue);
unsigned n_stdout_streams;
char *tty_path;
int max_level_store;
int max_level_syslog;
int max_level_kmsg;
int max_level_console;
int max_level_wall;
Storage storage;
SplitMode split_mode;
MMapCache *mmap;
Set *deferred_closes;
struct udev *udev;
uint64_t *kernel_seqnum;
bool dev_kmsg_readable:1;
bool send_watchdog:1;
bool sent_notify_ready:1;
bool sync_scheduled:1;
char machine_id_field[sizeof("_MACHINE_ID=") + 32];
char boot_id_field[sizeof("_BOOT_ID=") + 32];
char *hostname_field;
/* Cached cgroup root, so that we don't have to query that all the time */
char *cgroup_root;
usec_t watchdog_usec;
};
#define SERVER_MACHINE_ID(s) ((s)->machine_id_field + strlen("_MACHINE_ID="))
#define N_IOVEC_META_FIELDS 22
#define N_IOVEC_KERNEL_FIELDS 64
#define N_IOVEC_UDEV_FIELDS 32
#define N_IOVEC_OBJECT_FIELDS 14
#define N_IOVEC_PAYLOAD_FIELDS 15
void server_dispatch_message(Server *s, struct iovec *iovec, unsigned n, unsigned m, const struct ucred *ucred, const struct timeval *tv, const char *label, size_t label_len, const char *unit_id, int priority, pid_t object_pid);
void server_driver_message(Server *s, sd_id128_t message_id, const char *format, ...) _printf_(3,0) _sentinel_;
/* gperf lookup function */
const struct ConfigPerfItem* journald_gperf_lookup(const char *key, unsigned length);
int config_parse_storage(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
const char *storage_to_string(Storage s) _const_;
Storage storage_from_string(const char *s) _pure_;
int config_parse_split_mode(const char *unit, const char *filename, unsigned line, const char *section, unsigned section_line, const char *lvalue, int ltype, const char *rvalue, void *data, void *userdata);
const char *split_mode_to_string(SplitMode s) _const_;
SplitMode split_mode_from_string(const char *s) _pure_;
int server_init(Server *s);
void server_done(Server *s);
void server_sync(Server *s);
int server_vacuum(Server *s, bool verbose, bool patch_min_use);
void server_rotate(Server *s);
int server_schedule_sync(Server *s, int priority);
int server_flush_to_var(Server *s);
void server_maybe_append_tags(Server *s);
int server_process_datagram(sd_event_source *es, int fd, uint32_t revents, void *userdata);