2 * lxc: linux Container library
4 * (C) Copyright IBM Corp. 2007, 2008
7 * Cedric Le Goater <legoater@free.fr>
9 * This library is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU Lesser General Public
11 * License as published by the Free Software Foundation; either
12 * version 2.1 of the License, or (at your option) any later version.
14 * This library is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 * Lesser General Public License for more details.
19 * You should have received a copy of the GNU Lesser General Public
20 * License along with this library; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
25 #define __STDC_FORMAT_MACROS /* Required for PRIu64 to work. */
32 #include <sys/types.h>
47 #include "lxccontainer.h"
49 /* We're logging in seconds and nanoseconds. Assuming that the underlying
50 * datatype is currently at maximum a 64bit integer, we have a date string that
51 * is of maximum length (2^64 - 1) * 2 = (21 + 21) = 42.
53 #define LXC_LOG_TIME_SIZE ((LXC_NUMSTRLEN64)*2)
56 static int syslog_enable
= 0;
57 int lxc_quiet_specified
;
58 int lxc_log_use_global_fd
;
59 static int lxc_loglevel_specified
;
61 static char log_prefix
[LXC_LOG_PREFIX_SIZE
] = "lxc";
62 static char *log_fname
= NULL
;
63 static char *log_vmname
= NULL
;
65 lxc_log_define(lxc_log
, lxc
);
67 static int lxc_log_priority_to_syslog(int priority
)
70 case LXC_LOG_LEVEL_FATAL
:
72 case LXC_LOG_LEVEL_ALERT
:
74 case LXC_LOG_LEVEL_CRIT
:
76 case LXC_LOG_LEVEL_ERROR
:
78 case LXC_LOG_LEVEL_WARN
:
80 case LXC_LOG_LEVEL_NOTICE
:
81 case LXC_LOG_LEVEL_NOTSET
:
83 case LXC_LOG_LEVEL_INFO
:
85 case LXC_LOG_LEVEL_TRACE
:
86 case LXC_LOG_LEVEL_DEBUG
:
94 /*---------------------------------------------------------------------------*/
95 static int log_append_syslog(const struct lxc_log_appender
*appender
,
96 struct lxc_log_event
*event
)
105 va_copy(args
, *event
->vap
);
106 len
= vsnprintf(NULL
, 0, event
->fmt
, args
) + 1;
108 msg
= malloc(len
* sizeof(char));
111 rc
= vsnprintf(msg
, len
, event
->fmt
, *event
->vap
);
112 if (rc
== -1 || rc
>= len
) {
117 syslog(lxc_log_priority_to_syslog(event
->priority
),
118 "%s%s %s - %s:%s:%d - %s" ,
119 log_vmname
? log_vmname
: "",
120 log_vmname
? ":" : "",
122 event
->locinfo
->file
, event
->locinfo
->func
,
123 event
->locinfo
->line
,
129 /*---------------------------------------------------------------------------*/
130 static int log_append_stderr(const struct lxc_log_appender
*appender
,
131 struct lxc_log_event
*event
)
133 if (event
->priority
< LXC_LOG_LEVEL_ERROR
)
136 fprintf(stderr
, "%s: %s%s", log_prefix
, log_vmname
? log_vmname
: "", log_vmname
? ": " : "");
137 fprintf(stderr
, "%s: %s: %d ", event
->locinfo
->file
, event
->locinfo
->func
, event
->locinfo
->line
);
138 vfprintf(stderr
, event
->fmt
, *event
->vap
);
139 fprintf(stderr
, "\n");
143 /*---------------------------------------------------------------------------*/
144 int lxc_unix_epoch_to_utc(char *buf
, size_t bufsize
, const struct timespec
*time
)
146 int64_t epoch_to_days
, z
, era
, doe
, yoe
, year
, doy
, mp
, day
, month
,
147 d_in_s
, hours
, h_in_s
, minutes
, seconds
;
148 char nanosec
[LXC_NUMSTRLEN64
];
151 /* See https://howardhinnant.github.io/date_algorithms.html for an
152 * explanation of the algorithm used here.
155 /* Convert Epoch in seconds to number of days. */
156 epoch_to_days
= time
->tv_sec
/ 86400;
158 /* Shift the Epoch from 1970-01-01 to 0000-03-01. */
159 z
= epoch_to_days
+ 719468;
161 /* compute the era from the serial date by simply dividing by the number
162 * of days in an era (146097).
164 era
= (z
>= 0 ? z
: z
- 146096) / 146097;
166 /* The day-of-era (doe) can then be found by subtracting the era number
167 * times the number of days per era, from the serial date.
169 doe
= (z
- era
* 146097);
171 /* From the day-of-era (doe), the year-of-era (yoe, range [0, 399]) can
174 yoe
= (doe
- doe
/ 1460 + doe
/ 36524 - doe
/ 146096) / 365;
176 /* Given year-of-era, and era, one can now compute the year. */
177 year
= yoe
+ era
* 400;
179 /* Also the day-of-year, again with the year beginning on Mar. 1, can be
180 * computed from the day-of-era and year-of-era.
182 doy
= doe
- (365 * yoe
+ yoe
/ 4 - yoe
/ 100);
184 /* Given day-of-year, find the month number. */
185 mp
= (5 * doy
+ 2) / 153;
187 /* From day-of-year and month-of-year we can now easily compute
190 day
= doy
- (153 * mp
+ 2) / 5 + 1;
192 /* Transform the month number from the [0, 11] / [Mar, Feb] system to
193 * the civil system: [1, 12] to find the correct month.
195 month
= mp
+ (mp
< 10 ? 3 : -9);
197 /* The algorithm assumes that a year begins on 1 March, so add 1 before
202 /* Transform days in the epoch to seconds. */
203 d_in_s
= epoch_to_days
* 86400;
205 /* To find the current hour simply substract the Epoch_to_days from the
206 * total Epoch and divide by the number of seconds in an hour.
208 hours
= (time
->tv_sec
- d_in_s
) / 3600;
210 /* Transform hours to seconds. */
211 h_in_s
= hours
* 3600;
213 /* Calculate minutes by substracting the seconds for all days in the
214 * epoch and for all hours in the epoch and divide by the number of
215 * minutes in an hour.
217 minutes
= (time
->tv_sec
- d_in_s
- h_in_s
) / 60;
219 /* Calculate the seconds by substracting the seconds for all days in the
220 * epoch, hours in the epoch and minutes in the epoch.
222 seconds
= (time
->tv_sec
- d_in_s
- h_in_s
- (minutes
* 60));
224 /* Make string from nanoseconds. */
225 ret
= snprintf(nanosec
, LXC_NUMSTRLEN64
, "%"PRId64
, (int64_t)time
->tv_nsec
);
226 if (ret
< 0 || ret
>= LXC_NUMSTRLEN64
)
229 /* Create final timestamp for the log and shorten nanoseconds to 3
232 ret
= snprintf(buf
, bufsize
,
233 "%" PRId64
"%02" PRId64
"%02" PRId64
"%02" PRId64
234 "%02" PRId64
"%02" PRId64
".%.3s",
235 year
, month
, day
, hours
, minutes
, seconds
, nanosec
);
236 if (ret
< 0 || (size_t)ret
>= bufsize
)
242 /* This function needs to make extra sure that it is thread-safe. We had some
243 * problems with that before. This especially involves time-conversion
244 * functions. I don't want to find any localtime() or gmtime() functions or
245 * relatives in here. Not even localtime_r() or gmtime_r() or relatives. They
246 * all fiddle with global variables and locking in various libcs. They cause
247 * deadlocks when liblxc is used multi-threaded and no matter how smart you
248 * think you are, you __will__ cause trouble using them.
249 * (As a short example how this can cause trouble: LXD uses forkstart to fork
250 * off a new process that runs the container. At the same time the go runtime
251 * LXD relies on does its own multi-threading thing which we can't controll. The
252 * fork()ing + threading then seems to mess with the locking states in these
253 * time functions causing deadlocks.)
254 * The current solution is to be good old unix people and use the Epoch as our
255 * reference point and simply use the seconds and nanoseconds that have past
256 * since then. This relies on clock_gettime() which is explicitly marked MT-Safe
257 * with no restrictions! This way, anyone who is really strongly invested in
258 * getting the actual time the log entry was created, can just convert it for
259 * themselves. Our logging is mostly done for debugging purposes so don't try
260 * to make it pretty. Pretty might cost you thread-safety.
262 static int log_append_logfile(const struct lxc_log_appender
*appender
,
263 struct lxc_log_event
*event
)
265 char buffer
[LXC_LOG_BUFFER_SIZE
];
266 char date_time
[LXC_LOG_TIME_SIZE
];
271 if (!lxc_log_use_global_fd
&& current_config
)
272 fd_to_use
= current_config
->logfd
;
276 fd_to_use
= lxc_log_fd
;
281 if (lxc_unix_epoch_to_utc(date_time
, LXC_LOG_TIME_SIZE
, &event
->timestamp
) < 0)
284 n
= snprintf(buffer
, sizeof(buffer
),
285 "%15s%s%s %s %-8s %s - %s:%s:%d - ",
287 log_vmname
? " " : "",
288 log_vmname
? log_vmname
: "",
290 lxc_log_priority_to_string(event
->priority
),
292 event
->locinfo
->file
, event
->locinfo
->func
,
293 event
->locinfo
->line
);
298 if ((size_t)n
< (sizeof(buffer
) - 1))
299 n
+= vsnprintf(buffer
+ n
, sizeof(buffer
) - n
, event
->fmt
, *event
->vap
);
301 if ((size_t)n
>= sizeof(buffer
))
302 n
= sizeof(buffer
) - 1;
306 return write(fd_to_use
, buffer
, n
+ 1);
309 static struct lxc_log_appender log_appender_syslog
= {
311 .append
= log_append_syslog
,
315 static struct lxc_log_appender log_appender_stderr
= {
317 .append
= log_append_stderr
,
321 static struct lxc_log_appender log_appender_logfile
= {
323 .append
= log_append_logfile
,
327 static struct lxc_log_category log_root
= {
329 .priority
= LXC_LOG_LEVEL_ERROR
,
334 struct lxc_log_category lxc_log_category_lxc
= {
336 .priority
= LXC_LOG_LEVEL_ERROR
,
337 .appender
= &log_appender_logfile
,
341 /*---------------------------------------------------------------------------*/
342 static int build_dir(const char *name
)
347 /* Make copy of string since we'll be modifying it. */
350 ERROR("Out of memory while creating directory '%s'.", name
);
355 for (p
= n
+1; p
< e
; p
++) {
359 if (access(n
, F_OK
)) {
360 ret
= lxc_unpriv(mkdir(n
, 0755));
361 if (ret
&& errno
!= EEXIST
) {
362 SYSERROR("failed to create directory '%s'.", n
);
373 /*---------------------------------------------------------------------------*/
374 static int log_open(const char *name
)
379 fd
= lxc_unpriv(open(name
, O_CREAT
| O_WRONLY
|
380 O_APPEND
| O_CLOEXEC
, 0666));
382 ERROR("failed to open log file \"%s\" : %s", name
,
390 newfd
= fcntl(fd
, F_DUPFD_CLOEXEC
, 3);
392 ERROR("failed to dup log fd %d : %s", fd
, strerror(errno
));
399 * Build the path to the log file
400 * @name : the name of the container
401 * @lxcpath : the lxcpath to use as a basename or NULL to use LOGPATH
402 * Returns malloced path on success, or NULL on failure
404 static char *build_log_path(const char *name
, const char *lxcpath
)
407 int len
, ret
, use_dir
;
412 #if USE_CONFIGPATH_LOGS
419 * If USE_CONFIGPATH_LOGS is true or lxcpath is given, the resulting
421 * '$logpath' + '/' + '$name' + '/' + '$name' + '.log' + '\0'
423 * If USE_CONFIGPATH_LOGS is false the resulting path will be:
424 * '$logpath' + '/' + '$name' + '.log' + '\0'
426 len
= strlen(name
) + 6; /* 6 == '/' + '.log' + '\0' */
433 len
+= strlen(lxcpath
) + 1 + strlen(name
) + 1; /* add "/$container_name/" */
435 len
+= strlen(lxcpath
) + 1;
441 ret
= snprintf(p
, len
, "%s/%s/%s.log", lxcpath
, name
, name
);
443 ret
= snprintf(p
, len
, "%s/%s.log", lxcpath
, name
);
445 if (ret
< 0 || ret
>= len
) {
452 extern void lxc_log_close(void)
457 if (lxc_log_fd
== -1)
466 * This can be called:
467 * 1. when a program calls lxc_log_init with no logfile parameter (in which
468 * case the default is used). In this case lxc.loge can override this.
469 * 2. when a program calls lxc_log_init with a logfile parameter. In this
470 * case we don't want lxc.log to override this.
471 * 3. When a lxc.log entry is found in config file.
473 static int __lxc_log_set_file(const char *fname
, int create_dirs
)
475 /* we are overriding the default. */
476 if (lxc_log_fd
!= -1)
482 if (strlen(fname
) == 0) {
487 #if USE_CONFIGPATH_LOGS
488 /* We don't build_dir for the default if the default is i.e.
489 * /var/lib/lxc/$container/$container.log.
493 if (build_dir(fname
)) {
494 ERROR("failed to create dir for log file \"%s\" : %s", fname
,
499 lxc_log_fd
= log_open(fname
);
500 if (lxc_log_fd
== -1)
503 log_fname
= strdup(fname
);
507 static int _lxc_log_set_file(const char *name
, const char *lxcpath
, int create_dirs
)
512 logfile
= build_log_path(name
, lxcpath
);
514 ERROR("could not build log path");
517 ret
= __lxc_log_set_file(logfile
, create_dirs
);
522 extern int lxc_log_syslog(int facility
)
524 struct lxc_log_appender
*appender
;
526 openlog(log_prefix
, LOG_PID
, facility
);
527 if (!lxc_log_category_lxc
.appender
) {
528 lxc_log_category_lxc
.appender
= &log_appender_syslog
;
531 appender
= lxc_log_category_lxc
.appender
;
532 while (appender
->next
!= NULL
)
533 appender
= appender
->next
;
534 appender
->next
= &log_appender_syslog
;
539 extern void lxc_log_enable_syslog(void)
546 * Called from lxc front-end programs (like lxc-create, lxc-start) to
547 * initalize the log defaults.
549 extern int lxc_log_init(struct lxc_log
*log
)
551 int lxc_priority
= LXC_LOG_LEVEL_ERROR
;
554 if (lxc_log_fd
!= -1) {
555 WARN("lxc_log_init called with log already initialized");
560 lxc_priority
= lxc_log_priority_to_int(log
->level
);
562 if (!lxc_loglevel_specified
) {
563 lxc_log_category_lxc
.priority
= lxc_priority
;
564 lxc_loglevel_specified
= 1;
567 if (!lxc_quiet_specified
) {
569 lxc_log_category_lxc
.appender
->next
= &log_appender_stderr
;
573 lxc_log_set_prefix(log
->prefix
);
576 log_vmname
= strdup(log
->name
);
579 if (strcmp(log
->file
, "none") == 0)
581 ret
= __lxc_log_set_file(log
->file
, 1);
582 lxc_log_use_global_fd
= 1;
584 /* if no name was specified, there nothing to do */
591 log
->lxcpath
= LOGPATH
;
593 /* try LOGPATH if lxcpath is the default for the privileged containers */
594 if (!geteuid() && strcmp(LXCPATH
, log
->lxcpath
) == 0)
595 ret
= _lxc_log_set_file(log
->name
, NULL
, 0);
599 ret
= _lxc_log_set_file(log
->name
, log
->lxcpath
, 1);
601 /* try LOGPATH in case its writable by the caller */
603 ret
= _lxc_log_set_file(log
->name
, NULL
, 0);
607 * If !file, that is, if the user did not request this logpath, then
608 * ignore failures and continue logging to console
610 if (!log
->file
&& ret
!= 0) {
611 INFO("Ignoring failure to open default logfile.");
619 * This is called when we read a lxc.log.level entry in a lxc.conf file. This
620 * happens after processing command line arguments, which override the .conf
621 * settings. So only set the level if previously unset.
623 extern int lxc_log_set_level(int *dest
, int level
)
625 if (level
< 0 || level
>= LXC_LOG_LEVEL_NOTSET
) {
626 ERROR("invalid log priority %d", level
);
633 extern int lxc_log_get_level(void)
635 return lxc_log_category_lxc
.priority
;
638 extern bool lxc_log_has_valid_level(void)
640 int log_level
= lxc_log_get_level();
641 if (log_level
< 0 || log_level
>= LXC_LOG_LEVEL_NOTSET
)
647 * This is called when we read a lxc.logfile entry in a lxc.conf file. This
648 * happens after processing command line arguments, which override the .conf
649 * settings. So only set the file if previously unset.
651 extern int lxc_log_set_file(int *fd
, const char *fname
)
658 if (build_dir(fname
)) {
659 ERROR("failed to create dir for log file \"%s\" : %s", fname
,
664 *fd
= log_open(fname
);
670 extern const char *lxc_log_get_file(void)
675 extern void lxc_log_set_prefix(const char *prefix
)
677 strncpy(log_prefix
, prefix
, sizeof(log_prefix
));
678 log_prefix
[sizeof(log_prefix
) - 1] = 0;
681 extern const char *lxc_log_get_prefix(void)
686 extern void lxc_log_options_no_override()
688 lxc_quiet_specified
= 1;
689 lxc_loglevel_specified
= 1;