* separated by ',', and find the message after the ';' character.
*/
+enum log_flags {
+ LOG_DEFAULT = 0,
+ LOG_NOCONS = 1, /* already flushed, do not print to console */
+};
+
struct log {
u64 ts_nsec; /* timestamp in nanoseconds */
u16 len; /* length of entire record */
u16 text_len; /* length of text buffer */
u16 dict_len; /* length of dictionary buffer */
- u16 level; /* syslog level + facility */
+ u8 facility; /* syslog facility */
+ u8 flags:5; /* internal record flags */
+ u8 level:3; /* syslog level */
};
/*
#define LOG_LINE_MAX 1024
/* record buffer */
-#if !defined(CONFIG_64BIT) || defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
+#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
#define LOG_ALIGN 4
#else
-#define LOG_ALIGN 8
+#define LOG_ALIGN __alignof__(struct log)
#endif
#define __LOG_BUF_LEN (1 << CONFIG_LOG_BUF_SHIFT)
static char __log_buf[__LOG_BUF_LEN] __aligned(LOG_ALIGN);
/* insert record into the buffer, discard old ones, update heads */
static void log_store(int facility, int level,
+ enum log_flags flags, u64 ts_nsec,
const char *dict, u16 dict_len,
const char *text, u16 text_len)
{
msg->text_len = text_len;
memcpy(log_dict(msg), dict, dict_len);
msg->dict_len = dict_len;
- msg->level = (facility << 3) | (level & 7);
- msg->ts_nsec = local_clock();
+ msg->facility = facility;
+ msg->level = level & 7;
+ msg->flags = flags & 0x1f;
+ if (ts_nsec > 0)
+ msg->ts_nsec = ts_nsec;
+ else
+ msg->ts_nsec = local_clock();
memset(log_dict(msg) + dict_len, 0, pad_len);
msg->len = sizeof(struct log) + text_len + dict_len + pad_len;
if (!user)
return -EBADF;
- mutex_lock(&user->lock);
+ ret = mutex_lock_interruptible(&user->lock);
+ if (ret)
+ return ret;
raw_spin_lock(&logbuf_lock);
while (user->seq == log_next_seq) {
if (file->f_flags & O_NONBLOCK) {
ts_usec = msg->ts_nsec;
do_div(ts_usec, 1000);
len = sprintf(user->buf, "%u,%llu,%llu;",
- msg->level, user->seq, ts_usec);
+ (msg->facility << 3) | msg->level, user->seq, ts_usec);
/* escape non-printable characters */
for (i = 0; i < msg->text_len; i++) {
#endif
module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR);
+static size_t print_time(u64 ts, char *buf)
+{
+ unsigned long rem_nsec;
+
+ if (!printk_time)
+ return 0;
+
+ if (!buf)
+ return 15;
+
+ rem_nsec = do_div(ts, 1000000000);
+ return sprintf(buf, "[%5lu.%06lu] ",
+ (unsigned long)ts, rem_nsec / 1000);
+}
+
static size_t print_prefix(const struct log *msg, bool syslog, char *buf)
{
size_t len = 0;
}
}
- if (printk_time) {
- if (buf) {
- unsigned long long ts = msg->ts_nsec;
- unsigned long rem_nsec = do_div(ts, 1000000000);
-
- len += sprintf(buf + len, "[%5lu.%06lu] ",
- (unsigned long) ts, rem_nsec / 1000);
- } else {
- len += 15;
- }
- }
-
+ len += print_time(msg->ts_nsec, buf ? buf + len : NULL);
return len;
}
{
char *text;
struct log *msg;
- int len;
+ int len = 0;
text = kmalloc(LOG_LINE_MAX, GFP_KERNEL);
if (!text)
return -ENOMEM;
- raw_spin_lock_irq(&logbuf_lock);
- if (syslog_seq < log_first_seq) {
- /* messages are gone, move to first one */
- syslog_seq = log_first_seq;
- syslog_idx = log_first_idx;
- }
- msg = log_from_idx(syslog_idx);
- len = msg_print_text(msg, true, text, LOG_LINE_MAX);
- syslog_idx = log_next(syslog_idx);
- syslog_seq++;
- raw_spin_unlock_irq(&logbuf_lock);
+ while (size > 0) {
+ size_t n;
+
+ raw_spin_lock_irq(&logbuf_lock);
+ if (syslog_seq < log_first_seq) {
+ /* messages are gone, move to first one */
+ syslog_seq = log_first_seq;
+ syslog_idx = log_first_idx;
+ }
+ if (syslog_seq == log_next_seq) {
+ raw_spin_unlock_irq(&logbuf_lock);
+ break;
+ }
+ msg = log_from_idx(syslog_idx);
+ n = msg_print_text(msg, true, text, LOG_LINE_MAX);
+ if (n <= size) {
+ syslog_idx = log_next(syslog_idx);
+ syslog_seq++;
+ } else
+ n = 0;
+ raw_spin_unlock_irq(&logbuf_lock);
+
+ if (!n)
+ break;
+
+ len += n;
+ size -= n;
+ buf += n;
+ n = copy_to_user(buf - n, text, n);
- if (len > 0 && copy_to_user(buf, text, len))
- len = -EFAULT;
+ if (n) {
+ len -= n;
+ if (!len)
+ len = -EFAULT;
+ break;
+ }
+ }
kfree(text);
return len;
/*
* Find first record that fits, including all following records,
* into the user-provided buffer for this dump.
- */
+ */
seq = clear_seq;
idx = clear_idx;
while (seq < log_next_seq) {
idx = log_next(idx);
seq++;
}
+
+ /* move first record forward until length fits into the buffer */
seq = clear_seq;
idx = clear_idx;
while (len > size && seq < log_next_seq) {
seq++;
}
- /* last message in this dump */
+ /* last message fitting into this dump */
next_seq = log_next_seq;
len = 0;
{
bool clear = false;
static int saved_console_loglevel = -1;
+ static DEFINE_MUTEX(syslog_mutex);
int error;
error = check_syslog_permissions(type, from_file);
error = -EFAULT;
goto out;
}
+ error = mutex_lock_interruptible(&syslog_mutex);
+ if (error)
+ goto out;
error = wait_event_interruptible(log_wait,
syslog_seq != log_next_seq);
- if (error)
+ if (error) {
+ mutex_unlock(&syslog_mutex);
goto out;
+ }
error = syslog_print(buf, len);
+ mutex_unlock(&syslog_mutex);
break;
/* Read/clear last kernel messages */
case SYSLOG_ACTION_READ_CLEAR:
/* Clear ring buffer */
case SYSLOG_ACTION_CLEAR:
syslog_print_all(NULL, 0, true);
+ break;
/* Disable logging to console */
case SYSLOG_ACTION_CONSOLE_OFF:
if (saved_console_loglevel == -1)
}
}
+/*
+ * Continuation lines are buffered, and not committed to the record buffer
+ * until the line is complete, or a race forces it. The line fragments
+ * though, are printed immediately to the consoles to ensure everything has
+ * reached the console in case of a kernel crash.
+ */
+static struct cont {
+ char buf[LOG_LINE_MAX];
+ size_t len; /* length == 0 means unused buffer */
+ size_t cons; /* bytes written to console */
+ struct task_struct *owner; /* task of first print*/
+ u64 ts_nsec; /* time of first print */
+ u8 level; /* log level of first message */
+ u8 facility; /* log level of first message */
+ bool flushed:1; /* buffer sealed and committed */
+} cont;
+
+static void cont_flush(void)
+{
+ if (cont.flushed)
+ return;
+ if (cont.len == 0)
+ return;
+
+ log_store(cont.facility, cont.level, LOG_NOCONS, cont.ts_nsec,
+ NULL, 0, cont.buf, cont.len);
+
+ cont.flushed = true;
+}
+
+static bool cont_add(int facility, int level, const char *text, size_t len)
+{
+ if (cont.len && cont.flushed)
+ return false;
+
+ if (cont.len + len > sizeof(cont.buf)) {
+ cont_flush();
+ return false;
+ }
+
+ if (!cont.len) {
+ cont.facility = facility;
+ cont.level = level;
+ cont.owner = current;
+ cont.ts_nsec = local_clock();
+ cont.cons = 0;
+ cont.flushed = false;
+ }
+
+ memcpy(cont.buf + cont.len, text, len);
+ cont.len += len;
+ return true;
+}
+
+static size_t cont_print_text(char *text, size_t size)
+{
+ size_t textlen = 0;
+ size_t len;
+
+ if (cont.cons == 0) {
+ textlen += print_time(cont.ts_nsec, text);
+ size -= textlen;
+ }
+
+ len = cont.len - cont.cons;
+ if (len > 0) {
+ if (len+1 > size)
+ len = size-1;
+ memcpy(text + textlen, cont.buf + cont.cons, len);
+ textlen += len;
+ cont.cons = cont.len;
+ }
+
+ if (cont.flushed) {
+ text[textlen++] = '\n';
+ /* got everything, release buffer */
+ cont.len = 0;
+ }
+ return textlen;
+}
+
asmlinkage int vprintk_emit(int facility, int level,
const char *dict, size_t dictlen,
const char *fmt, va_list args)
{
static int recursion_bug;
- static char cont_buf[LOG_LINE_MAX];
- static size_t cont_len;
- static int cont_level;
- static struct task_struct *cont_task;
static char textbuf[LOG_LINE_MAX];
char *text = textbuf;
size_t text_len;
recursion_bug = 0;
printed_len += strlen(recursion_msg);
/* emit KERN_CRIT message */
- log_store(0, 2, NULL, 0, recursion_msg, printed_len);
+ log_store(0, 2, LOG_DEFAULT, 0,
+ NULL, 0, recursion_msg, printed_len);
}
/*
}
if (!newline) {
- if (cont_len && (prefix || cont_task != current)) {
- /*
- * Flush earlier buffer, which is either from a
- * different thread, or when we got a new prefix.
- */
- log_store(facility, cont_level, NULL, 0, cont_buf, cont_len);
- cont_len = 0;
- }
-
- if (!cont_len) {
- cont_level = level;
- cont_task = current;
- }
+ /*
+ * Flush the conflicting buffer. An earlier newline was missing,
+ * or another task also prints continuation lines.
+ */
+ if (cont.len && (prefix || cont.owner != current))
+ cont_flush();
- /* buffer or append to earlier buffer from the same thread */
- if (cont_len + text_len > sizeof(cont_buf))
- text_len = sizeof(cont_buf) - cont_len;
- memcpy(cont_buf + cont_len, text, text_len);
- cont_len += text_len;
+ /* buffer line if possible, otherwise store it right away */
+ if (!cont_add(facility, level, text, text_len))
+ log_store(facility, level, LOG_DEFAULT, 0,
+ dict, dictlen, text, text_len);
} else {
- if (cont_len && cont_task == current) {
- if (prefix) {
- /*
- * New prefix from the same thread; flush. We
- * either got no earlier newline, or we race
- * with an interrupt.
- */
- log_store(facility, cont_level,
- NULL, 0, cont_buf, cont_len);
- cont_len = 0;
- }
+ bool stored = false;
- /* append to the earlier buffer and flush */
- if (cont_len + text_len > sizeof(cont_buf))
- text_len = sizeof(cont_buf) - cont_len;
- memcpy(cont_buf + cont_len, text, text_len);
- cont_len += text_len;
- log_store(facility, cont_level,
- NULL, 0, cont_buf, cont_len);
- cont_len = 0;
- cont_task = NULL;
- printed_len = cont_len;
- } else {
- /* ordinary single and terminated line */
- log_store(facility, level,
- dict, dictlen, text, text_len);
- printed_len = text_len;
+ /*
+ * If an earlier newline was missing and it was the same task,
+ * either merge it with the current buffer and flush, or if
+ * there was a race with interrupts (prefix == true) then just
+ * flush it out and store this line separately.
+ */
+ if (cont.len && cont.owner == current) {
+ if (!prefix)
+ stored = cont_add(facility, level, text, text_len);
+ cont_flush();
}
+
+ if (!stored)
+ log_store(facility, level, LOG_DEFAULT, 0,
+ dict, dictlen, text, text_len);
}
+ printed_len += text_len;
/*
* Try to acquire and then immediately release the console semaphore.
#else
#define LOG_LINE_MAX 0
+static struct cont {
+ size_t len;
+ size_t cons;
+ u8 level;
+ bool flushed:1;
+} cont;
static struct log *log_from_idx(u32 idx) { return NULL; }
static u32 log_next(u32 idx) { return 0; }
static void call_console_drivers(int level, const char *text, size_t len) {}
static size_t msg_print_text(const struct log *msg, bool syslog,
char *buf, size_t size) { return 0; }
+static size_t cont_print_text(char *text, size_t size) { return 0; }
#endif /* CONFIG_PRINTK */
*/
void console_unlock(void)
{
+ static char text[LOG_LINE_MAX];
static u64 seen_seq;
unsigned long flags;
bool wake_klogd = false;
console_may_schedule = 0;
+ /* flush buffered message fragment immediately to console */
+ raw_spin_lock_irqsave(&logbuf_lock, flags);
+ if (cont.len && (cont.cons < cont.len || cont.flushed)) {
+ size_t len;
+
+ len = cont_print_text(text, sizeof(text));
+ raw_spin_unlock(&logbuf_lock);
+ stop_critical_timings();
+ call_console_drivers(cont.level, text, len);
+ start_critical_timings();
+ local_irq_restore(flags);
+ } else
+ raw_spin_unlock_irqrestore(&logbuf_lock, flags);
+
again:
for (;;) {
struct log *msg;
- static char text[LOG_LINE_MAX];
size_t len;
int level;
console_seq = log_first_seq;
console_idx = log_first_idx;
}
-
+skip:
if (console_seq == log_next_seq)
break;
msg = log_from_idx(console_idx);
- level = msg->level & 7;
+ if (msg->flags & LOG_NOCONS) {
+ /*
+ * Skip record we have buffered and already printed
+ * directly to the console when we received it.
+ */
+ console_idx = log_next(console_idx);
+ console_seq++;
+ goto skip;
+ }
+ level = msg->level;
len = msg_print_text(msg, false, text, sizeof(text));
console_idx = log_next(console_idx);
* kmsg_dump - dump kernel log to kernel message dumpers.
* @reason: the reason (oops, panic etc) for dumping
*
- * Iterate through each of the dump devices and call the oops/panic
- * callbacks with the log buffer.
+ * Call each of the registered dumper's dump() callback, which can
+ * retrieve the kmsg records with kmsg_dump_get_line() or
+ * kmsg_dump_get_buffer().
*/
void kmsg_dump(enum kmsg_dump_reason reason)
{
- u64 idx;
struct kmsg_dumper *dumper;
- const char *s1, *s2;
- unsigned long l1, l2;
unsigned long flags;
if ((reason > KMSG_DUMP_OOPS) && !always_kmsg_dump)
return;
- /* Theoretically, the log could move on after we do this, but
- there's not a lot we can do about that. The new messages
- will overwrite the start of what we dump. */
+ rcu_read_lock();
+ list_for_each_entry_rcu(dumper, &dump_list, list) {
+ if (dumper->max_reason && reason > dumper->max_reason)
+ continue;
+
+ /* initialize iterator with data about the stored records */
+ dumper->active = true;
+
+ raw_spin_lock_irqsave(&logbuf_lock, flags);
+ dumper->cur_seq = clear_seq;
+ dumper->cur_idx = clear_idx;
+ dumper->next_seq = log_next_seq;
+ dumper->next_idx = log_next_idx;
+ raw_spin_unlock_irqrestore(&logbuf_lock, flags);
+
+ /* invoke dumper which will iterate over records */
+ dumper->dump(dumper, reason);
+
+ /* reset iterator */
+ dumper->active = false;
+ }
+ rcu_read_unlock();
+}
+
+/**
+ * kmsg_dump_get_line - retrieve one kmsg log line
+ * @dumper: registered kmsg dumper
+ * @syslog: include the "<4>" prefixes
+ * @line: buffer to copy the line to
+ * @size: maximum size of the buffer
+ * @len: length of line placed into buffer
+ *
+ * Start at the beginning of the kmsg buffer, with the oldest kmsg
+ * record, and copy one record into the provided buffer.
+ *
+ * Consecutive calls will return the next available record moving
+ * towards the end of the buffer with the youngest messages.
+ *
+ * A return value of FALSE indicates that there are no more records to
+ * read.
+ */
+bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog,
+ char *line, size_t size, size_t *len)
+{
+ unsigned long flags;
+ struct log *msg;
+ size_t l = 0;
+ bool ret = false;
+
+ if (!dumper->active)
+ goto out;
raw_spin_lock_irqsave(&logbuf_lock, flags);
- if (syslog_seq < log_first_seq)
- idx = syslog_idx;
- else
- idx = log_first_idx;
+ if (dumper->cur_seq < log_first_seq) {
+ /* messages are gone, move to first available one */
+ dumper->cur_seq = log_first_seq;
+ dumper->cur_idx = log_first_idx;
+ }
- if (idx > log_next_idx) {
- s1 = log_buf;
- l1 = log_next_idx;
+ /* last entry */
+ if (dumper->cur_seq >= log_next_seq) {
+ raw_spin_unlock_irqrestore(&logbuf_lock, flags);
+ goto out;
+ }
- s2 = log_buf + idx;
- l2 = log_buf_len - idx;
- } else {
- s1 = "";
- l1 = 0;
+ msg = log_from_idx(dumper->cur_idx);
+ l = msg_print_text(msg, syslog,
+ line, size);
- s2 = log_buf + idx;
- l2 = log_next_idx - idx;
+ dumper->cur_idx = log_next(dumper->cur_idx);
+ dumper->cur_seq++;
+ ret = true;
+ raw_spin_unlock_irqrestore(&logbuf_lock, flags);
+out:
+ if (len)
+ *len = l;
+ return ret;
+}
+EXPORT_SYMBOL_GPL(kmsg_dump_get_line);
+
+/**
+ * kmsg_dump_get_buffer - copy kmsg log lines
+ * @dumper: registered kmsg dumper
+ * @syslog: include the "<4>" prefixes
+ * @buf: buffer to copy the line to
+ * @size: maximum size of the buffer
+ * @len: length of line placed into buffer
+ *
+ * Start at the end of the kmsg buffer and fill the provided buffer
+ * with as many of the the *youngest* kmsg records that fit into it.
+ * If the buffer is large enough, all available kmsg records will be
+ * copied with a single call.
+ *
+ * Consecutive calls will fill the buffer with the next block of
+ * available older records, not including the earlier retrieved ones.
+ *
+ * A return value of FALSE indicates that there are no more records to
+ * read.
+ */
+bool kmsg_dump_get_buffer(struct kmsg_dumper *dumper, bool syslog,
+ char *buf, size_t size, size_t *len)
+{
+ unsigned long flags;
+ u64 seq;
+ u32 idx;
+ u64 next_seq;
+ u32 next_idx;
+ size_t l = 0;
+ bool ret = false;
+
+ if (!dumper->active)
+ goto out;
+
+ raw_spin_lock_irqsave(&logbuf_lock, flags);
+ if (dumper->cur_seq < log_first_seq) {
+ /* messages are gone, move to first available one */
+ dumper->cur_seq = log_first_seq;
+ dumper->cur_idx = log_first_idx;
}
+
+ /* last entry */
+ if (dumper->cur_seq >= dumper->next_seq) {
+ raw_spin_unlock_irqrestore(&logbuf_lock, flags);
+ goto out;
+ }
+
+ /* calculate length of entire buffer */
+ seq = dumper->cur_seq;
+ idx = dumper->cur_idx;
+ while (seq < dumper->next_seq) {
+ struct log *msg = log_from_idx(idx);
+
+ l += msg_print_text(msg, true, NULL, 0);
+ idx = log_next(idx);
+ seq++;
+ }
+
+ /* move first record forward until length fits into the buffer */
+ seq = dumper->cur_seq;
+ idx = dumper->cur_idx;
+ while (l > size && seq < dumper->next_seq) {
+ struct log *msg = log_from_idx(idx);
+
+ l -= msg_print_text(msg, true, NULL, 0);
+ idx = log_next(idx);
+ seq++;
+ }
+
+ /* last message in next interation */
+ next_seq = seq;
+ next_idx = idx;
+
+ l = 0;
+ while (seq < dumper->next_seq) {
+ struct log *msg = log_from_idx(idx);
+
+ l += msg_print_text(msg, syslog,
+ buf + l, size - l);
+
+ idx = log_next(idx);
+ seq++;
+ }
+
+ dumper->next_seq = next_seq;
+ dumper->next_idx = next_idx;
+ ret = true;
raw_spin_unlock_irqrestore(&logbuf_lock, flags);
+out:
+ if (len)
+ *len = l;
+ return ret;
+}
+EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer);
- rcu_read_lock();
- list_for_each_entry_rcu(dumper, &dump_list, list)
- dumper->dump(dumper, reason, s1, l1, s2, l2);
- rcu_read_unlock();
+/**
+ * kmsg_dump_rewind - reset the interator
+ * @dumper: registered kmsg dumper
+ *
+ * Reset the dumper's iterator so that kmsg_dump_get_line() and
+ * kmsg_dump_get_buffer() can be called again and used multiple
+ * times within the same dumper.dump() callback.
+ */
+void kmsg_dump_rewind(struct kmsg_dumper *dumper)
+{
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&logbuf_lock, flags);
+ dumper->cur_seq = clear_seq;
+ dumper->cur_idx = clear_idx;
+ dumper->next_seq = log_next_seq;
+ dumper->next_idx = log_next_idx;
+ raw_spin_unlock_irqrestore(&logbuf_lock, flags);
}
+EXPORT_SYMBOL_GPL(kmsg_dump_rewind);
#endif
projects / karo-tx-linux.git / blobdiff