[systemd-devel] [RFC][PATCH 2/2] journald: add support for wall forwarding

Zbigniew Jędrzejewski-Szmek zbyszek at in.waw.pl
Wed Mar 5 05:50:28 PST 2014


On Wed, Mar 05, 2014 at 01:45:51PM +0100, Sebastian Thorarensen wrote:
> This will let journald forward logs as messages sent to all logged in
> users (like wall).
> 
> Two options are added:
>  * ForwardToWall (default no)
Is there a good reason not to set it to yes by default?

>  * MaxLevelWall (default emerg)
> 'ForwardToWall' is overridable by kernel command line option
> 'systemd.journald.forward_to_wall'.
> 
> This can be used to emulate the traditional syslogd behaviour of sending
> emergency messages to all logged in users.
> ---
>  Makefile.am                      |    2 ++
>  man/journald.conf.xml            |   40 +++++++++++++++-----------
>  src/journal/journald-gperf.gperf |    2 ++
>  src/journal/journald-native.c    |    4 +++
>  src/journal/journald-server.c    |    7 +++++
>  src/journal/journald-server.h    |    2 ++
>  src/journal/journald-stream.c    |    4 +++
>  src/journal/journald-syslog.c    |    4 +++
>  src/journal/journald-wall.c      |   59 ++++++++++++++++++++++++++++++++++++++
>  src/journal/journald-wall.h      |   26 +++++++++++++++++
>  src/journal/journald.conf        |    2 ++
>  11 files changed, 136 insertions(+), 16 deletions(-)
>  create mode 100644 src/journal/journald-wall.c
>  create mode 100644 src/journal/journald-wall.h
> 
> diff --git a/Makefile.am b/Makefile.am
> index f99cef7..02a2fbf 100644
> --- a/Makefile.am
> +++ b/Makefile.am
> @@ -3227,6 +3227,8 @@ libsystemd_journal_core_la_SOURCES = \
>  	src/journal/journald-server.h \
>  	src/journal/journald-console.c \
>  	src/journal/journald-console.h \
> +	src/journal/journald-wall.c \
> +	src/journal/journald-wall.h \
>  	src/journal/journald-native.c \
>  	src/journal/journald-native.h \
>  	src/journal/journald-rate-limit.c \
> diff --git a/man/journald.conf.xml b/man/journald.conf.xml
> index a814ec1..723d445 100644
> --- a/man/journald.conf.xml
> +++ b/man/journald.conf.xml
> @@ -381,24 +381,28 @@
>                                  <term><varname>ForwardToSyslog=</varname></term>
>                                  <term><varname>ForwardToKMsg=</varname></term>
>                                  <term><varname>ForwardToConsole=</varname></term>
> +                                <term><varname>ForwardToWall=</varname></term>
>  
>                                  <listitem><para>Control whether log
>                                  messages received by the journal
>                                  daemon shall be forwarded to a
>                                  traditional syslog daemon, to the
> -                                kernel log buffer (kmsg), or to the
> -                                system console. These options take
> -                                boolean arguments. If forwarding to
> -                                syslog is enabled but no syslog daemon
> -                                is running, the respective option has
> -                                no effect. By default, only forwarding
> -                                to syslog is enabled. These settings
> -                                may be overridden at boot time with
> -                                the kernel command line options
> +                                kernel log buffer (kmsg), to the
> +                                system console, or sent as wall
> +                                messages to all logged-in users. These
> +                                options take boolean arguments. If
> +                                forwarding to syslog is enabled but no
> +                                syslog daemon is running, the
> +                                respective option has no effect. By
> +                                default, only forwarding to syslog is
> +                                enabled. These settings may be
> +                                overridden at boot time with the
> +                                kernel command line options
>                                  <literal>systemd.journald.forward_to_syslog=</literal>,
> -                                <literal>systemd.journald.forward_to_kmsg=</literal>
> +                                <literal>systemd.journald.forward_to_kmsg=</literal>,
> +                                <literal>systemd.journald.forward_to_console=</literal>
>                                  and
> -                                <literal>systemd.journald.forward_to_console=</literal>.
> +                                <literal>systemd.journald.forward_to_wall=</literal>.
>                                  When forwarding to the console, the
>                                  TTY to log to can be changed
>                                  with <varname>TTYPath=</varname>,
> @@ -410,12 +414,14 @@
>                                  <term><varname>MaxLevelSyslog=</varname></term>
>                                  <term><varname>MaxLevelKMsg=</varname></term>
>                                  <term><varname>MaxLevelConsole=</varname></term>
> +                                <term><varname>MaxLevelWall=</varname></term>
>  
>                                  <listitem><para>Controls the maximum
>                                  log level of messages that are stored
> -                                on disk, forwarded to syslog, kmsg or
> -                                the console (if that is enabled, see
> -                                above). As argument, takes one of
> +                                on disk, forwarded to syslog, kmsg,
> +                                the console or wall (if that is
> +                                enabled, see above). As argument,
> +                                takes one of
>                                  <literal>emerg</literal>,
>                                  <literal>alert</literal>,
>                                  <literal>crit</literal>,
> @@ -436,9 +442,11 @@
>                                  written to disk and forwarded to
>                                  syslog. Defaults to
>                                  <literal>notice</literal> for
> -                                <varname>MaxLevelKMsg=</varname> and
> +                                <varname>MaxLevelKMsg=</varname>,
>                                  <literal>info</literal> for
> -                                <varname>MaxLevelConsole=</varname>.</para></listitem>
> +                                <varname>MaxLevelConsole=</varname> and
> +                                <literal>emerg</literal> for
> +                                <varname>MaxLevelWall=</varname>.</para></listitem>
>                          </varlistentry>
>  
>                          <varlistentry>
> diff --git a/src/journal/journald-gperf.gperf b/src/journal/journald-gperf.gperf
> index 83bbbc8..74554c1 100644
> --- a/src/journal/journald-gperf.gperf
> +++ b/src/journal/journald-gperf.gperf
> @@ -32,9 +32,11 @@ Journal.MaxFileSec,         config_parse_sec,        0, offsetof(Server, max_fil
>  Journal.ForwardToSyslog,    config_parse_bool,       0, offsetof(Server, forward_to_syslog)
>  Journal.ForwardToKMsg,      config_parse_bool,       0, offsetof(Server, forward_to_kmsg)
>  Journal.ForwardToConsole,   config_parse_bool,       0, offsetof(Server, forward_to_console)
> +Journal.ForwardToWall,      config_parse_bool,       0, offsetof(Server, forward_to_wall)
>  Journal.TTYPath,            config_parse_path,       0, offsetof(Server, tty_path)
>  Journal.MaxLevelStore,      config_parse_log_level,  0, offsetof(Server, max_level_store)
>  Journal.MaxLevelSyslog,     config_parse_log_level,  0, offsetof(Server, max_level_syslog)
>  Journal.MaxLevelKMsg,       config_parse_log_level,  0, offsetof(Server, max_level_kmsg)
>  Journal.MaxLevelConsole,    config_parse_log_level,  0, offsetof(Server, max_level_console)
> +Journal.MaxLevelWall,       config_parse_log_level,  0, offsetof(Server, max_level_wall)
>  Journal.SplitMode,          config_parse_split_mode, 0, offsetof(Server, split_mode)
> diff --git a/src/journal/journald-native.c b/src/journal/journald-native.c
> index 359d962..0509c1e 100644
> --- a/src/journal/journald-native.c
> +++ b/src/journal/journald-native.c
> @@ -31,6 +31,7 @@
>  #include "journald-kmsg.h"
>  #include "journald-console.h"
>  #include "journald-syslog.h"
> +#include "journald-wall.h"
>  
>  /* Make sure not to make this smaller than the maximum coredump
>   * size. See COREDUMP_MAX in coredump.c */
> @@ -265,6 +266,9 @@ void server_process_native_message(
>  
>                  if (s->forward_to_console)
>                          server_forward_console(s, priority, identifier, message, ucred);
> +
> +                if (s->forward_to_wall)
> +                        server_forward_wall(s, priority, identifier, message, ucred);
>          }
>  
>          server_dispatch_message(s, iovec, n, m, ucred, tv, label, label_len, NULL, priority, object_pid);
> diff --git a/src/journal/journald-server.c b/src/journal/journald-server.c
> index 2a90b44..2fcb4d7 100644
> --- a/src/journal/journald-server.c
> +++ b/src/journal/journald-server.c
> @@ -1319,6 +1319,12 @@ static int server_parse_proc_cmdline(Server *s) {
>                                  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.forward_to_wall=")) {
> +                        r = parse_boolean(word + 33);
> +                        if (r < 0)
> +                                log_warning("Failed to parse forward to wall switch %s. Ignoring.", word + 33);
> +                        else
> +                                s->forward_to_wall = r;
>                  } else if (startswith(word, "systemd.journald"))
>                          log_warning("Invalid systemd.journald parameter. Ignoring.");
>          }
> @@ -1471,6 +1477,7 @@ int server_init(Server *s) {
>          s->max_level_syslog = LOG_DEBUG;
>          s->max_level_kmsg = LOG_NOTICE;
>          s->max_level_console = LOG_INFO;
> +        s->max_level_wall = LOG_EMERG;
>  
>          memset(&s->system_metrics, 0xFF, sizeof(s->system_metrics));
>          memset(&s->runtime_metrics, 0xFF, sizeof(s->runtime_metrics));
> diff --git a/src/journal/journald-server.h b/src/journal/journald-server.h
> index 2a81061..e468b82 100644
> --- a/src/journal/journald-server.h
> +++ b/src/journal/journald-server.h
> @@ -97,6 +97,7 @@ typedef struct Server {
>          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;
> @@ -119,6 +120,7 @@ typedef struct Server {
>          int max_level_syslog;
>          int max_level_kmsg;
>          int max_level_console;
> +        int max_level_wall;
>  
>          Storage storage;
>          SplitMode split_mode;
> diff --git a/src/journal/journald-stream.c b/src/journal/journald-stream.c
> index 36fc755..c46ffe5 100644
> --- a/src/journal/journald-stream.c
> +++ b/src/journal/journald-stream.c
> @@ -35,6 +35,7 @@
>  #include "journald-syslog.h"
>  #include "journald-kmsg.h"
>  #include "journald-console.h"
> +#include "journald-wall.h"
>  
>  #define STDOUT_STREAMS_MAX 4096
>  
> @@ -106,6 +107,9 @@ static int stdout_stream_log(StdoutStream *s, const char *p) {
>          if (s->forward_to_console || s->server->forward_to_console)
>                  server_forward_console(s->server, priority, s->identifier, p, &s->ucred);
>  
> +        if (s->server->forward_to_wall)
> +                server_forward_wall(s->server, priority, s->identifier, p, &s->ucred);
> +
>          IOVEC_SET_STRING(iovec[n++], "_TRANSPORT=stdout");
>  
>          syslog_priority[strlen("PRIORITY=")] = '0' + LOG_PRI(priority);
> diff --git a/src/journal/journald-syslog.c b/src/journal/journald-syslog.c
> index 241f7ed..cbb944f 100644
> --- a/src/journal/journald-syslog.c
> +++ b/src/journal/journald-syslog.c
> @@ -30,6 +30,7 @@
>  #include "journald-syslog.h"
>  #include "journald-kmsg.h"
>  #include "journald-console.h"
> +#include "journald-wall.h"
>  
>  /* Warn once every 30s if we missed syslog message */
>  #define WARN_FORWARD_SYSLOG_MISSED_USEC (30 * USEC_PER_SEC)
> @@ -380,6 +381,9 @@ void server_process_syslog_message(
>          if (s->forward_to_console)
>                  server_forward_console(s, priority, identifier, buf, ucred);
>  
> +        if (s->forward_to_wall)
> +                server_forward_wall(s, priority, identifier, buf, ucred);
> +
>          IOVEC_SET_STRING(iovec[n++], "_TRANSPORT=syslog");
>  
>          if (asprintf(&syslog_priority, "PRIORITY=%i", priority & LOG_PRIMASK) >= 0)
> diff --git a/src/journal/journald-wall.c b/src/journal/journald-wall.c
> new file mode 100644
> index 0000000..55a44bd
> --- /dev/null
> +++ b/src/journal/journald-wall.c
> @@ -0,0 +1,59 @@
> +/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
> +
> +/***
> +  This file is part of systemd.
> +
> +  Copyright 2014 Sebastian Thorarensen
> +
> +  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 "utmp-wtmp.h"
> +#include "journald-server.h"
> +#include "journald-wall.h"
> +
> +void server_forward_wall(
> +                Server *s,
> +                int priority,
> +                const char *identifier,
> +                const char *message,
> +                struct ucred *ucred) {
> +
> +        char header_pid[16];
header_pid[DECIMAL_STR_MAX(pid_t) + sizeof("[]"];

> +        _cleanup_free_ char *ident_buf = NULL, *l = NULL;
> +
> +        assert(s);
> +        assert(message);
> +
> +        if (LOG_PRI(priority) > s->max_level_wall)
> +                return;
> +
> +        if (ucred) {
> +                if (!identifier) {
> +                        get_process_comm(ucred->pid, &ident_buf);
> +                        identifier = ident_buf;
> +                }
> +
> +                snprintf(header_pid, sizeof(header_pid), "[%lu]", (unsigned long) ucred->pid);
Use "["PID_FMT"]" for the format.

> +                char_array_0(header_pid);
Remove this.

> +        }
> +
> +        if (asprintf(&l, "%s%s: %s", strempty(identifier), strempty(header_pid), message) < 0) {
> +                log_debug("Failed to allocate wall message: %m");
> +                return;
> +        }
> +
> +        if (utmp_wall(l, "systemd-journald", NULL) < 0)
> +                log_debug("Failed to send wall message: %m");
> +}
> diff --git a/src/journal/journald-wall.h b/src/journal/journald-wall.h
> new file mode 100644
> index 0000000..93c3cec
> --- /dev/null
> +++ b/src/journal/journald-wall.h
> @@ -0,0 +1,26 @@
> +/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
> +
> +#pragma once
> +
> +/***
> +  This file is part of systemd.
> +
> +  Copyright 2014 Sebastian Thorarensen
> +
> +  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 "journald-server.h"
> +
> +void server_forward_wall(Server *s, int priority, const char *identifier, const char *message, struct ucred *ucred);
> diff --git a/src/journal/journald.conf b/src/journal/journald.conf
> index 54f6833..16ea1f1 100644
> --- a/src/journal/journald.conf
> +++ b/src/journal/journald.conf
> @@ -26,8 +26,10 @@
>  #ForwardToSyslog=yes
>  #ForwardToKMsg=no
>  #ForwardToConsole=no
> +#ForwardToWall=no
>  #TTYPath=/dev/console
>  #MaxLevelStore=debug
>  #MaxLevelSyslog=debug
>  #MaxLevelKMsg=notice
>  #MaxLevelConsole=info
> +#MaxLevelWall=emerg

Zbyszek


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