Systemd/src/journal/journald-console.c
Lennart Poettering e6a7ec4b8e io-util: add new IOVEC_INIT/IOVEC_MAKE macros
This adds IOVEC_INIT() and IOVEC_MAKE() for initializing iovec structures
from a pointer and a size. On top of these IOVEC_INIT_STRING() and
IOVEC_MAKE_STRING() are added which take a string and automatically
determine the size of the string using strlen().

This patch removes the old IOVEC_SET_STRING() macro, given that
IOVEC_MAKE_STRING() is now useful for similar purposes. Note that the
old IOVEC_SET_STRING() invocations were two characters shorter than the
new ones using IOVEC_MAKE_STRING(), but I think the new syntax is more
readable and more generic as it simply resolves to a C99 literal
structure initialization. Moreover, we can use very similar syntax now
for initializing strings and pointer+size iovec entries. We canalso use
the new macros to initialize function parameters on-the-fly or array
definitions. And given that we shouldn't have so many ways to do the
same stuff, let's just settle on the new macros.

(This also converts some code to use _cleanup_ where dynamically
allocated strings were using IOVEC_SET_STRING() before, to modernize
things a bit)
2017-09-22 15:28:04 +02:00

121 lines
4 KiB
C

/***
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 <fcntl.h>
#include <sys/socket.h>
#include <time.h>
#include "alloc-util.h"
#include "fd-util.h"
#include "fileio.h"
#include "format-util.h"
#include "io-util.h"
#include "journald-console.h"
#include "journald-server.h"
#include "parse-util.h"
#include "process-util.h"
#include "stdio-util.h"
#include "terminal-util.h"
static bool prefix_timestamp(void) {
static int cached_printk_time = -1;
if (_unlikely_(cached_printk_time < 0)) {
_cleanup_free_ char *p = NULL;
cached_printk_time =
read_one_line_file("/sys/module/printk/parameters/time", &p) >= 0
&& parse_boolean(p) > 0;
}
return cached_printk_time;
}
void server_forward_console(
Server *s,
int priority,
const char *identifier,
const char *message,
const struct ucred *ucred) {
struct iovec iovec[5];
struct timespec ts;
char tbuf[sizeof("[] ")-1 + DECIMAL_STR_MAX(ts.tv_sec) + DECIMAL_STR_MAX(ts.tv_nsec)-3 + 1];
char header_pid[sizeof("[]: ")-1 + DECIMAL_STR_MAX(pid_t)];
_cleanup_free_ char *ident_buf = NULL;
_cleanup_close_ int fd = -1;
const char *tty;
int n = 0;
assert(s);
assert(message);
if (LOG_PRI(priority) > s->max_level_console)
return;
/* First: timestamp */
if (prefix_timestamp()) {
assert_se(clock_gettime(CLOCK_MONOTONIC, &ts) == 0);
xsprintf(tbuf, "[%5"PRI_TIME".%06"PRI_NSEC"] ",
ts.tv_sec,
(nsec_t)ts.tv_nsec / 1000);
iovec[n++] = IOVEC_MAKE_STRING(tbuf);
}
/* Second: identifier and PID */
if (ucred) {
if (!identifier) {
get_process_comm(ucred->pid, &ident_buf);
identifier = ident_buf;
}
xsprintf(header_pid, "["PID_FMT"]: ", ucred->pid);
if (identifier)
iovec[n++] = IOVEC_MAKE_STRING(identifier);
iovec[n++] = IOVEC_MAKE_STRING(header_pid);
} else if (identifier) {
iovec[n++] = IOVEC_MAKE_STRING(identifier);
iovec[n++] = IOVEC_MAKE_STRING(": ");
}
/* Fourth: message */
iovec[n++] = IOVEC_MAKE_STRING(message);
iovec[n++] = IOVEC_MAKE_STRING("\n");
tty = s->tty_path ?: "/dev/console";
/* Before you ask: yes, on purpose we open/close the console for each log line we write individually. This is a
* good strategy to avoid journald getting killed by the kernel's SAK concept (it doesn't fix this entirely,
* but minimizes the time window the kernel might end up killing journald due to SAK). It also makes things
* easier for us so that we don't have to recover from hangups and suchlike triggered on the console. */
fd = open_terminal(tty, O_WRONLY|O_NOCTTY|O_CLOEXEC);
if (fd < 0) {
log_debug_errno(fd, "Failed to open %s for logging: %m", tty);
return;
}
if (writev(fd, iovec, n) < 0)
log_debug_errno(errno, "Failed to write to %s for logging: %m", tty);
}