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git.ipfire.org Git - thirdparty/systemd.git/blob - src/journal/journald-console.c
1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
4 #include <sys/socket.h>
7 #include "alloc-util.h"
10 #include "format-util.h"
12 #include "journald-console.h"
13 #include "journald-server.h"
14 #include "parse-util.h"
15 #include "process-util.h"
16 #include "stdio-util.h"
17 #include "terminal-util.h"
19 static bool prefix_timestamp(void) {
21 static int cached_printk_time
= -1;
23 if (_unlikely_(cached_printk_time
< 0)) {
24 _cleanup_free_
char *p
= NULL
;
27 read_one_line_file("/sys/module/printk/parameters/time", &p
) >= 0
28 && parse_boolean(p
) > 0;
31 return cached_printk_time
;
34 void server_forward_console(
37 const char *identifier
,
39 const struct ucred
*ucred
) {
41 struct iovec iovec
[5];
43 char tbuf
[STRLEN("[] ") + DECIMAL_STR_MAX(ts
.tv_sec
) + DECIMAL_STR_MAX(ts
.tv_nsec
)-3 + 1];
44 char header_pid
[STRLEN("[]: ") + DECIMAL_STR_MAX(pid_t
)];
45 _cleanup_free_
char *ident_buf
= NULL
;
46 _cleanup_close_
int fd
= -EBADF
;
53 if (LOG_PRI(priority
) > s
->max_level_console
)
56 /* First: timestamp */
57 if (prefix_timestamp()) {
58 assert_se(clock_gettime(CLOCK_MONOTONIC
, &ts
) == 0);
59 xsprintf(tbuf
, "[%5"PRI_TIME
".%06"PRI_NSEC
"] ",
61 (nsec_t
)ts
.tv_nsec
/ 1000);
63 iovec
[n
++] = IOVEC_MAKE_STRING(tbuf
);
66 /* Second: identifier and PID */
69 (void) get_process_comm(ucred
->pid
, &ident_buf
);
70 identifier
= ident_buf
;
73 xsprintf(header_pid
, "["PID_FMT
"]: ", ucred
->pid
);
76 iovec
[n
++] = IOVEC_MAKE_STRING(identifier
);
78 iovec
[n
++] = IOVEC_MAKE_STRING(header_pid
);
79 } else if (identifier
) {
80 iovec
[n
++] = IOVEC_MAKE_STRING(identifier
);
81 iovec
[n
++] = IOVEC_MAKE_STRING(": ");
85 iovec
[n
++] = IOVEC_MAKE_STRING(message
);
86 iovec
[n
++] = IOVEC_MAKE_STRING("\n");
88 tty
= s
->tty_path
?: "/dev/console";
90 /* Before you ask: yes, on purpose we open/close the console for each log line we write individually. This is a
91 * good strategy to avoid journald getting killed by the kernel's SAK concept (it doesn't fix this entirely,
92 * but minimizes the time window the kernel might end up killing journald due to SAK). It also makes things
93 * easier for us so that we don't have to recover from hangups and suchlike triggered on the console. */
95 fd
= open_terminal(tty
, O_WRONLY
|O_NOCTTY
|O_CLOEXEC
);
97 log_debug_errno(fd
, "Failed to open %s for logging: %m", tty
);
101 if (writev(fd
, iovec
, n
) < 0)
102 log_debug_errno(errno
, "Failed to write to %s for logging: %m", tty
);