#include <syslog.h>
#include <time.h>
#include <unistd.h>
+#include "async-append.h"
#include "coverage.h"
#include "dirs.h"
#include "dynamic-string.h"
#include "ofpbuf.h"
+#include "ovs-thread.h"
#include "sat-math.h"
#include "svec.h"
#include "timeval.h"
#define n_vlog_modules ARRAY_SIZE(vlog_modules)
#endif
+/* Protects the 'pattern' in all "struct facility"s, so that a race between
+ * changing and reading the pattern does not cause an access to freed
+ * memory. */
+static struct ovs_rwlock pattern_rwlock = OVS_RWLOCK_INITIALIZER;
+
/* Information about each facility. */
struct facility {
const char *name; /* Name. */
- char *pattern; /* Current pattern. */
+ char *pattern OVS_GUARDED_BY(pattern_rwlock); /* Current pattern. */
bool default_pattern; /* Whether current pattern is the default. */
};
static struct facility facilities[VLF_N_FACILITIES] = {
#undef VLOG_FACILITY
};
-/* VLF_FILE configuration. */
-static char *log_file_name;
-static int log_fd = -1;
+/* Sequence number for the message currently being composed. */
+DEFINE_STATIC_PER_THREAD_DATA(unsigned int, msg_num, 0);
-/* vlog initialized? */
-static bool vlog_inited;
+/* VLF_FILE configuration.
+ *
+ * All of the following is protected by 'log_file_mutex', which nests inside
+ * pattern_rwlock. */
+static struct ovs_mutex log_file_mutex = OVS_ADAPTIVE_MUTEX_INITIALIZER;
+static char *log_file_name OVS_GUARDED_BY(log_file_mutex);
+static int log_fd OVS_GUARDED_BY(log_file_mutex) = -1;
+static struct async_append *log_writer OVS_GUARDED_BY(log_file_mutex);
+static bool log_async OVS_GUARDED_BY(log_file_mutex);
static void format_log_message(const struct vlog_module *, enum vlog_level,
- enum vlog_facility, unsigned int msg_num,
+ enum vlog_facility,
const char *message, va_list, struct ds *)
- PRINTF_FORMAT(5, 0);
+ PRINTF_FORMAT(4, 0) OVS_REQ_RDLOCK(&pattern_rwlock);
/* Searches the 'n_names' in 'names'. Returns the index of a match for
* 'target', or 'n_names' if no name matches. */
}
static void
-update_min_level(struct vlog_module *module)
+update_min_level(struct vlog_module *module) OVS_REQUIRES(&log_file_mutex)
{
enum vlog_facility facility;
assert(facility >= 0 && facility < VLF_N_FACILITIES);
assert(level < VLL_N_LEVELS);
+ ovs_mutex_lock(&log_file_mutex);
if (!module) {
struct vlog_module **mp;
module->levels[facility] = level;
update_min_level(module);
}
+ ovs_mutex_unlock(&log_file_mutex);
}
/* Sets the logging level for the given 'module' and 'facility' to 'level'. A
do_set_pattern(enum vlog_facility facility, const char *pattern)
{
struct facility *f = &facilities[facility];
+
+ ovs_rwlock_wrlock(&pattern_rwlock);
if (!f->default_pattern) {
free(f->pattern);
} else {
f->default_pattern = false;
}
f->pattern = xstrdup(pattern);
+ ovs_rwlock_unlock(&pattern_rwlock);
}
/* Sets the pattern for the given 'facility' to 'pattern'. */
}
}
-/* Returns the name of the log file used by VLF_FILE, or a null pointer if no
- * log file has been set. (A non-null return value does not assert that the
- * named log file is in use: if vlog_set_log_file() or vlog_reopen_log_file()
- * fails, it still sets the log file name.) */
-const char *
-vlog_get_log_file(void)
-{
- return log_file_name;
-}
-
/* Sets the name of the log file used by VLF_FILE to 'file_name', or to the
* default file name if 'file_name' is null. Returns 0 if successful,
* otherwise a positive errno value. */
int
vlog_set_log_file(const char *file_name)
{
- char *old_log_file_name;
+ char *new_log_file_name;
struct vlog_module **mp;
- int error;
+ struct stat old_stat;
+ struct stat new_stat;
+ int new_log_fd;
+ bool same_file;
+ bool log_close;
+
+ /* Open new log file. */
+ new_log_file_name = (file_name
+ ? xstrdup(file_name)
+ : xasprintf("%s/%s.log", ovs_logdir(), program_name));
+ new_log_fd = open(new_log_file_name, O_WRONLY | O_CREAT | O_APPEND, 0666);
+ if (new_log_fd < 0) {
+ VLOG_WARN("failed to open %s for logging: %s",
+ new_log_file_name, ovs_strerror(errno));
+ free(new_log_file_name);
+ return errno;
+ }
+
+ /* If the new log file is the same one we already have open, bail out. */
+ ovs_mutex_lock(&log_file_mutex);
+ same_file = (log_fd >= 0
+ && new_log_fd >= 0
+ && !fstat(log_fd, &old_stat)
+ && !fstat(new_log_fd, &new_stat)
+ && old_stat.st_dev == new_stat.st_dev
+ && old_stat.st_ino == new_stat.st_ino);
+ ovs_mutex_unlock(&log_file_mutex);
+ if (same_file) {
+ close(new_log_fd);
+ free(new_log_file_name);
+ return 0;
+ }
- /* Close old log file. */
- if (log_fd >= 0) {
+ /* Log closing old log file (we can't log while holding log_file_mutex). */
+ ovs_mutex_lock(&log_file_mutex);
+ log_close = log_fd >= 0;
+ ovs_mutex_unlock(&log_file_mutex);
+ if (log_close) {
VLOG_INFO("closing log file");
+ }
+
+ /* Close old log file, if any, and install new one. */
+ ovs_mutex_lock(&log_file_mutex);
+ if (log_fd >= 0) {
+ free(log_file_name);
close(log_fd);
- log_fd = -1;
+ async_append_destroy(log_writer);
}
- /* Update log file name and free old name. The ordering is important
- * because 'file_name' might be 'log_file_name' or some suffix of it. */
- old_log_file_name = log_file_name;
- log_file_name = (file_name
- ? xstrdup(file_name)
- : xasprintf("%s/%s.log", ovs_logdir(), program_name));
- free(old_log_file_name);
- file_name = NULL; /* Might have been freed. */
+ log_file_name = xstrdup(new_log_file_name);
+ log_fd = new_log_fd;
+ if (log_async) {
+ log_writer = async_append_create(new_log_fd);
+ }
- /* Open new log file and update min_levels[] to reflect whether we actually
- * have a log_file. */
- log_fd = open(log_file_name, O_WRONLY | O_CREAT | O_APPEND, 0666);
for (mp = vlog_modules; mp < &vlog_modules[n_vlog_modules]; mp++) {
update_min_level(*mp);
}
+ ovs_mutex_unlock(&log_file_mutex);
- /* Log success or failure. */
- if (log_fd < 0) {
- VLOG_WARN("failed to open %s for logging: %s",
- log_file_name, ovs_strerror(errno));
- error = errno;
- } else {
- VLOG_INFO("opened log file %s", log_file_name);
- error = 0;
- }
+ /* Log opening new log file (we can't log while holding log_file_mutex). */
+ VLOG_INFO("opened log file %s", new_log_file_name);
+ free(new_log_file_name);
- return error;
+ return 0;
}
/* Closes and then attempts to re-open the current log file. (This is useful
int
vlog_reopen_log_file(void)
{
- struct stat old, new;
+ char *fn;
- /* Skip re-opening if there's nothing to reopen. */
- if (!log_file_name) {
- return 0;
- }
+ ovs_mutex_lock(&log_file_mutex);
+ fn = log_file_name ? xstrdup(log_file_name) : NULL;
+ ovs_mutex_unlock(&log_file_mutex);
- /* Skip re-opening if it would be a no-op because the old and new files are
- * the same. (This avoids writing "closing log file" followed immediately
- * by "opened log file".) */
- if (log_fd >= 0
- && !fstat(log_fd, &old)
- && !stat(log_file_name, &new)
- && old.st_dev == new.st_dev
- && old.st_ino == new.st_ino) {
+ if (fn) {
+ int error = vlog_set_log_file(fn);
+ free(fn);
+ return error;
+ } else {
return 0;
}
-
- return vlog_set_log_file(log_file_name);
}
/* Set debugging levels. Returns null if successful, otherwise an error
vlog_unixctl_reopen(struct unixctl_conn *conn, int argc OVS_UNUSED,
const char *argv[] OVS_UNUSED, void *aux OVS_UNUSED)
{
- if (log_file_name) {
+ bool has_log_file;
+
+ ovs_mutex_lock(&log_file_mutex);
+ has_log_file = log_file_name != NULL;
+ ovs_mutex_unlock(&log_file_mutex);
+
+ if (has_log_file) {
int error = vlog_reopen_log_file();
if (error) {
unixctl_command_reply_error(conn, ovs_strerror(errno));
set_rate_limits(conn, argc, argv, false);
}
-/* Initializes the logging subsystem and registers its unixctl server
- * commands. */
-void
-vlog_init(void)
+static void
+vlog_init__(void)
{
static char *program_name_copy;
time_t now;
- if (vlog_inited) {
- return;
- }
- vlog_inited = true;
-
/* openlog() is allowed to keep the pointer passed in, without making a
* copy. The daemonize code sometimes frees and replaces 'program_name',
* so make a private copy just for openlog(). (We keep a pointer to the
vlog_unixctl_reopen, NULL);
}
-/* Closes the logging subsystem. */
+/* Initializes the logging subsystem and registers its unixctl server
+ * commands. */
void
-vlog_exit(void)
+vlog_init(void)
{
- if (vlog_inited) {
- closelog();
- vlog_inited = false;
+ static pthread_once_t once = PTHREAD_ONCE_INIT;
+ pthread_once(&once, vlog_init__);
+}
+
+/* Enables VLF_FILE log output to be written asynchronously to disk.
+ * Asynchronous file writes avoid blocking the process in the case of a busy
+ * disk, but on the other hand they are less robust: there is a chance that the
+ * write will not make it to the log file if the process crashes soon after the
+ * log call. */
+void
+vlog_enable_async(void)
+{
+ ovs_mutex_lock(&log_file_mutex);
+ log_async = true;
+ if (log_fd >= 0 && !log_writer) {
+ log_writer = async_append_create(log_fd);
}
+ ovs_mutex_unlock(&log_file_mutex);
}
/* Print the current logging level for each module. */
static void
format_log_message(const struct vlog_module *module, enum vlog_level level,
- enum vlog_facility facility, unsigned int msg_num,
+ enum vlog_facility facility,
const char *message, va_list args_, struct ds *s)
{
char tmp[128];
}
break;
case 'N':
- ds_put_format(s, "%u", msg_num);
+ ds_put_format(s, "%u", *msg_num_get_unsafe());
break;
case 'n':
ds_put_char(s, '\n');
{
bool log_to_console = module->levels[VLF_CONSOLE] >= level;
bool log_to_syslog = module->levels[VLF_SYSLOG] >= level;
- bool log_to_file = module->levels[VLF_FILE] >= level && log_fd >= 0;
+ bool log_to_file;
+
+ ovs_mutex_lock(&log_file_mutex);
+ log_to_file = module->levels[VLF_FILE] >= level && log_fd >= 0;
+ ovs_mutex_unlock(&log_file_mutex);
if (log_to_console || log_to_syslog || log_to_file) {
int save_errno = errno;
- static unsigned int msg_num;
struct ds s;
vlog_init();
ds_init(&s);
ds_reserve(&s, 1024);
- msg_num++;
+ ++*msg_num_get();
+ ovs_rwlock_rdlock(&pattern_rwlock);
if (log_to_console) {
- format_log_message(module, level, VLF_CONSOLE, msg_num,
- message, args, &s);
+ format_log_message(module, level, VLF_CONSOLE, message, args, &s);
ds_put_char(&s, '\n');
fputs(ds_cstr(&s), stderr);
}
char *save_ptr = NULL;
char *line;
- format_log_message(module, level, VLF_SYSLOG, msg_num,
- message, args, &s);
+ format_log_message(module, level, VLF_SYSLOG, message, args, &s);
for (line = strtok_r(s.string, "\n", &save_ptr); line;
line = strtok_r(NULL, "\n", &save_ptr)) {
syslog(syslog_level, "%s", line);
}
if (log_to_file) {
- format_log_message(module, level, VLF_FILE, msg_num,
- message, args, &s);
+ format_log_message(module, level, VLF_FILE, message, args, &s);
ds_put_char(&s, '\n');
- ignore(write(log_fd, s.string, s.length));
+
+ ovs_mutex_lock(&log_file_mutex);
+ if (log_fd >= 0) {
+ if (log_writer) {
+ async_append_write(log_writer, s.string, s.length);
+ if (level == VLL_EMER) {
+ async_append_flush(log_writer);
+ }
+ } else {
+ ignore(write(log_fd, s.string, s.length));
+ }
+ }
+ ovs_mutex_unlock(&log_file_mutex);
}
+ ovs_rwlock_unlock(&pattern_rwlock);
ds_destroy(&s);
errno = save_errno;
return true;
}
+ ovs_mutex_lock(&rl->mutex);
if (!token_bucket_withdraw(&rl->token_bucket, VLOG_MSG_TOKENS)) {
time_t now = time_now();
if (!rl->n_dropped) {
}
rl->last_dropped = now;
rl->n_dropped++;
+ ovs_mutex_unlock(&rl->mutex);
return true;
}
- if (rl->n_dropped) {
+ if (!rl->n_dropped) {
+ ovs_mutex_unlock(&rl->mutex);
+ } else {
time_t now = time_now();
+ unsigned int n_dropped = rl->n_dropped;
unsigned int first_dropped_elapsed = now - rl->first_dropped;
unsigned int last_dropped_elapsed = now - rl->last_dropped;
+ rl->n_dropped = 0;
+ ovs_mutex_unlock(&rl->mutex);
vlog(module, level,
"Dropped %u log messages in last %u seconds (most recently, "
"%u seconds ago) due to excessive rate",
- rl->n_dropped, first_dropped_elapsed, last_dropped_elapsed);
-
- rl->n_dropped = 0;
+ n_dropped, first_dropped_elapsed, last_dropped_elapsed);
}
+
return false;
}