*/
static DEFINE_RAW_SPINLOCK(logbuf_lock);
+#ifdef CONFIG_PRINTK
/* the next printk record to read by syslog(READ) or /proc/kmsg */
static u64 syslog_seq;
static u32 syslog_idx;
/* index and sequence number of the next record to store in the buffer */
static u64 log_next_seq;
-#ifdef CONFIG_PRINTK
static u32 log_next_idx;
+/* the next printk record to write to the console */
+static u64 console_seq;
+static u32 console_idx;
+static enum log_flags console_prev;
+
/* the next printk record to read after the last 'clear' command */
static u64 clear_seq;
static u32 clear_idx;
-#define LOG_LINE_MAX 1024
+#define PREFIX_MAX 32
+#define LOG_LINE_MAX 1024 - PREFIX_MAX
/* record buffer */
#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
struct devkmsg_user {
u64 seq;
u32 idx;
+ enum log_flags prev;
struct mutex lock;
char buf[8192];
};
struct log *msg;
u64 ts_usec;
size_t i;
+ char cont = '-';
size_t len;
ssize_t ret;
msg = log_from_idx(user->idx);
ts_usec = msg->ts_nsec;
do_div(ts_usec, 1000);
- len = sprintf(user->buf, "%u,%llu,%llu;",
- (msg->facility << 3) | msg->level, user->seq, ts_usec);
+
+ /*
+ * If we couldn't merge continuation line fragments during the print,
+ * export the stored flags to allow an optional external merge of the
+ * records. Merging the records isn't always neccessarily correct, like
+ * when we hit a race during printing. In most cases though, it produces
+ * better readable output. 'c' in the record flags mark the first
+ * fragment of a line, '+' the following.
+ */
+ if (msg->flags & LOG_CONT && !(user->prev & LOG_CONT))
+ cont = 'c';
+ else if ((msg->flags & LOG_CONT) ||
+ ((user->prev & LOG_CONT) && !(msg->flags & LOG_PREFIX)))
+ cont = '+';
+
+ len = sprintf(user->buf, "%u,%llu,%llu,%c;",
+ (msg->facility << 3) | msg->level,
+ user->seq, ts_usec, cont);
+ user->prev = msg->flags;
/* escape non-printable characters */
for (i = 0; i < msg->text_len; i++) {
VMCOREINFO_SYMBOL(log_buf_len);
VMCOREINFO_SYMBOL(log_first_idx);
VMCOREINFO_SYMBOL(log_next_idx);
+ /*
+ * Export struct log size and field offsets. User space tools can
+ * parse it and detect any changes to structure down the line.
+ */
+ VMCOREINFO_STRUCT_SIZE(log);
+ VMCOREINFO_OFFSET(log, ts_nsec);
+ VMCOREINFO_OFFSET(log, len);
+ VMCOREINFO_OFFSET(log, text_len);
+ VMCOREINFO_OFFSET(log, dict_len);
}
#endif
if (buf) {
if (print_prefix(msg, syslog, NULL) +
- text_len + 1>= size - len)
+ text_len + 1 >= size - len)
break;
if (prefix)
struct log *msg;
int len = 0;
- text = kmalloc(LOG_LINE_MAX, GFP_KERNEL);
+ text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL);
if (!text)
return -ENOMEM;
skip = syslog_partial;
msg = log_from_idx(syslog_idx);
- n = msg_print_text(msg, syslog_prev, true, text, LOG_LINE_MAX);
+ n = msg_print_text(msg, syslog_prev, true, text,
+ LOG_LINE_MAX + PREFIX_MAX);
if (n - syslog_partial <= size) {
/* message fits into buffer, move forward */
syslog_idx = log_next(syslog_idx);
char *text;
int len = 0;
- text = kmalloc(LOG_LINE_MAX, GFP_KERNEL);
+ text = kmalloc(LOG_LINE_MAX + PREFIX_MAX, GFP_KERNEL);
if (!text)
return -ENOMEM;
struct log *msg = log_from_idx(idx);
int textlen;
- textlen = msg_print_text(msg, prev, true, text, LOG_LINE_MAX);
+ textlen = msg_print_text(msg, prev, true, text,
+ LOG_LINE_MAX + PREFIX_MAX);
if (textlen < 0) {
len = textlen;
break;
return do_syslog(type, buf, len, SYSLOG_FROM_CALL);
}
-#ifdef CONFIG_KGDB_KDB
-/* kdb dmesg command needs access to the syslog buffer. do_syslog()
- * uses locks so it cannot be used during debugging. Just tell kdb
- * where the start and end of the physical and logical logs are. This
- * is equivalent to do_syslog(3).
- */
-void kdb_syslog_data(char *syslog_data[4])
-{
- syslog_data[0] = log_buf;
- syslog_data[1] = log_buf + log_buf_len;
- syslog_data[2] = log_buf + log_first_idx;
- syslog_data[3] = log_buf + log_next_idx;
-}
-#endif /* CONFIG_KGDB_KDB */
-
static bool __read_mostly ignore_loglevel;
static int __init ignore_loglevel_setup(char *str)
u64 ts_nsec; /* time of first print */
u8 level; /* log level of first message */
u8 facility; /* log level of first message */
+ enum log_flags flags; /* prefix, newline flags */
bool flushed:1; /* buffer sealed and committed */
} cont;
-static void cont_flush(void)
+static void cont_flush(enum log_flags flags)
{
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;
+ if (cont.cons) {
+ /*
+ * If a fragment of this line was directly flushed to the
+ * console; wait for the console to pick up the rest of the
+ * line. LOG_NOCONS suppresses a duplicated output.
+ */
+ log_store(cont.facility, cont.level, flags | LOG_NOCONS,
+ cont.ts_nsec, NULL, 0, cont.buf, cont.len);
+ cont.flags = flags;
+ cont.flushed = true;
+ } else {
+ /*
+ * If no fragment of this line ever reached the console,
+ * just submit it to the store and free the buffer.
+ */
+ log_store(cont.facility, cont.level, flags, 0,
+ NULL, 0, cont.buf, cont.len);
+ cont.len = 0;
+ }
}
static bool cont_add(int facility, int level, const char *text, size_t len)
return false;
if (cont.len + len > sizeof(cont.buf)) {
- cont_flush();
+ /* the line gets too long, split it up in separate records */
+ cont_flush(LOG_CONT);
return false;
}
cont.level = level;
cont.owner = current;
cont.ts_nsec = local_clock();
+ cont.flags = 0;
cont.cons = 0;
cont.flushed = false;
}
memcpy(cont.buf + cont.len, text, len);
cont.len += len;
+
+ if (cont.len > (sizeof(cont.buf) * 80) / 100)
+ cont_flush(LOG_CONT);
+
return true;
}
size_t textlen = 0;
size_t len;
- if (cont.cons == 0) {
+ if (cont.cons == 0 && (console_prev & LOG_NEWLINE)) {
textlen += print_time(cont.ts_nsec, text);
size -= textlen;
}
}
if (cont.flushed) {
- text[textlen++] = '\n';
+ if (cont.flags & LOG_NEWLINE)
+ text[textlen++] = '\n';
/* got everything, release buffer */
cont.len = 0;
}
* or another task also prints continuation lines.
*/
if (cont.len && (lflags & LOG_PREFIX || cont.owner != current))
- cont_flush();
+ cont_flush(LOG_NEWLINE);
/* buffer line if possible, otherwise store it right away */
if (!cont_add(facility, level, text, text_len))
if (cont.len && cont.owner == current) {
if (!(lflags & LOG_PREFIX))
stored = cont_add(facility, level, text, text_len);
- cont_flush();
+ cont_flush(LOG_NEWLINE);
}
if (!stored)
}
EXPORT_SYMBOL(printk);
-#else
+#else /* CONFIG_PRINTK */
+#define LOG_LINE_MAX 0
+#define PREFIX_MAX 0
#define LOG_LINE_MAX 0
+static u64 syslog_seq;
+static u32 syslog_idx;
+static u64 console_seq;
+static u32 console_idx;
+static enum log_flags syslog_prev;
+static u64 log_first_seq;
+static u32 log_first_idx;
+static u64 log_next_seq;
+static enum log_flags console_prev;
static struct cont {
size_t len;
size_t cons;
this_cpu_or(printk_pending, PRINTK_PENDING_WAKEUP);
}
-/* the next printk record to write to the console */
-static u64 console_seq;
-static u32 console_idx;
-static enum log_flags console_prev;
+static void console_cont_flush(char *text, size_t size)
+{
+ unsigned long flags;
+ size_t len;
+
+ raw_spin_lock_irqsave(&logbuf_lock, flags);
+
+ if (!cont.len)
+ goto out;
+
+ /*
+ * We still queue earlier records, likely because the console was
+ * busy. The earlier ones need to be printed before this one, we
+ * did not flush any fragment so far, so just let it queue up.
+ */
+ if (console_seq < log_next_seq && !cont.cons)
+ goto out;
+
+ len = cont_print_text(text, size);
+ raw_spin_unlock(&logbuf_lock);
+ stop_critical_timings();
+ call_console_drivers(cont.level, text, len);
+ start_critical_timings();
+ local_irq_restore(flags);
+ return;
+out:
+ raw_spin_unlock_irqrestore(&logbuf_lock, flags);
+}
/**
* console_unlock - unlock the console system
*/
void console_unlock(void)
{
- static char text[LOG_LINE_MAX];
+ static char text[LOG_LINE_MAX + PREFIX_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);
-
+ console_cont_flush(text, sizeof(text));
again:
for (;;) {
struct log *msg;
* will properly dump everything later.
*/
msg->flags &= ~LOG_NOCONS;
+ console_prev = msg->flags;
goto skip;
}
}
/**
- * kmsg_dump_get_line - retrieve one kmsg log line
+ * kmsg_dump_get_line_nolock - retrieve one kmsg log line (unlocked version)
* @dumper: registered kmsg dumper
* @syslog: include the "<4>" prefixes
* @line: buffer to copy the line to
*
* A return value of FALSE indicates that there are no more records to
* read.
+ *
+ * The function is similar to kmsg_dump_get_line(), but grabs no locks.
*/
-bool kmsg_dump_get_line(struct kmsg_dumper *dumper, bool syslog,
- char *line, size_t size, size_t *len)
+bool kmsg_dump_get_line_nolock(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 (dumper->cur_seq < log_first_seq) {
/* messages are gone, move to first available one */
dumper->cur_seq = log_first_seq;
}
/* last entry */
- if (dumper->cur_seq >= log_next_seq) {
- raw_spin_unlock_irqrestore(&logbuf_lock, flags);
+ if (dumper->cur_seq >= log_next_seq)
goto out;
- }
msg = log_from_idx(dumper->cur_idx);
l = msg_print_text(msg, 0, syslog, line, size);
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;
}
+
+/**
+ * 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;
+ bool ret;
+
+ raw_spin_lock_irqsave(&logbuf_lock, flags);
+ ret = kmsg_dump_get_line_nolock(dumper, syslog, line, size, len);
+ raw_spin_unlock_irqrestore(&logbuf_lock, flags);
+
+ return ret;
+}
EXPORT_SYMBOL_GPL(kmsg_dump_get_line);
/**
}
EXPORT_SYMBOL_GPL(kmsg_dump_get_buffer);
+/**
+ * kmsg_dump_rewind_nolock - reset the interator (unlocked version)
+ * @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.
+ *
+ * The function is similar to kmsg_dump_rewind(), but grabs no locks.
+ */
+void kmsg_dump_rewind_nolock(struct kmsg_dumper *dumper)
+{
+ dumper->cur_seq = clear_seq;
+ dumper->cur_idx = clear_idx;
+ dumper->next_seq = log_next_seq;
+ dumper->next_idx = log_next_idx;
+}
+
/**
* kmsg_dump_rewind - reset the interator
* @dumper: registered kmsg 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;
+ kmsg_dump_rewind_nolock(dumper);
raw_spin_unlock_irqrestore(&logbuf_lock, flags);
}
EXPORT_SYMBOL_GPL(kmsg_dump_rewind);
projects / firefly-linux-kernel-4.4.55.git / blobdiff