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Commit 3ce9a7c0 authored by Kay Sievers's avatar Kay Sievers Committed by Greg Kroah-Hartman
Browse files

printk() - restore prefix/timestamp printing for multi-newline strings 



Calls like:
  printk("\n *** DEADLOCK ***\n\n");
will print 3 properly indented, separated, syslog + timestamp prefixed lines in
the log output.

Reported-By: default avatarSasha Levin <levinsasha928@gmail.com>
Signed-off-by: default avatarKay Sievers <kay@vrfy.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 1fce6779

kernel/printk.c

+76 −51
Original line number Diff line number Diff line
@@ -448,7 +448,7 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf, 


	/* escape non-printable characters */

	for (i = 0; i < msg->text_len; i++) {

		char c = log_text(msg)[i];

		unsigned char c = log_text(msg)[i];



		if (c < ' ' || c >= 128)

			len += sprintf(user->buf + len, "\\x%02x", c);
@@ -461,7 +461,7 @@ static ssize_t devkmsg_read(struct file *file, char __user *buf, 
		bool line = true;



		for (i = 0; i < msg->dict_len; i++) {

			char c = log_dict(msg)[i];

			unsigned char c = log_dict(msg)[i];



			if (line) {

				user->buf[len++] = ' ';
@@ -785,56 +785,81 @@ static bool printk_time; 
#endif

module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR);



static size_t prepend_timestamp(unsigned long long t, char *buf)

static size_t print_prefix(const struct log *msg, bool syslog, char *buf)

{

	unsigned long rem_ns;

	size_t len = 0;



	if (!printk_time)

		return 0;

	if (syslog) {

		if (buf) {

			len += sprintf(buf, "<%u>", msg->level);

		} else {

			len += 3;

			if (msg->level > 9)

				len++;

			if (msg->level > 99)

				len++;

		}

	}



	if (!buf)

		return 15;

	if (printk_time) {

		if (buf) {

			unsigned long long ts = msg->ts_nsec;

			unsigned long rem_nsec = do_div(ts, 1000000000);



	rem_ns = do_div(t, 1000000000);

			len += sprintf(buf + len, "[%5lu.%06lu] ",

					 (unsigned long) ts, rem_nsec / 1000);

		} else {

			len += 15;

		}

	}



	return sprintf(buf, "[%5lu.%06lu] ",

		       (unsigned long) t, rem_ns / 1000);

	return len;

}



static int syslog_print_line(u32 idx, char *text, size_t size)

static size_t msg_print_text(const struct log *msg, bool syslog,

			     char *buf, size_t size)

{

	struct log *msg;

	size_t len;

	const char *text = log_text(msg);

	size_t text_size = msg->text_len;

	size_t len = 0;



	msg = log_from_idx(idx);

	if (!text) {

		/* calculate length only */

		len = 3;

	do {

		const char *next = memchr(text, '\n', text_size);

		size_t text_len;



		if (msg->level > 9)

			len++;

		if (msg->level > 99)

			len++;

		len += prepend_timestamp(0, NULL);

		if (next) {

			text_len = next - text;

			next++;

			text_size -= next - text;

		} else {

			text_len = text_size;

		}



		len += msg->text_len;

		len++;

		return len;

		if (buf) {

			if (print_prefix(msg, syslog, NULL) +

			    text_len + 1>= size - len)

				break;



			len += print_prefix(msg, syslog, buf + len);

			memcpy(buf + len, text, text_len);

			len += text_len;

			buf[len++] = '\n';

		} else {

			/* SYSLOG_ACTION_* buffer size only calculation */

			len += print_prefix(msg, syslog, NULL);

			len += text_len + 1;

		}



	len = sprintf(text, "<%u>", msg->level);

	len += prepend_timestamp(msg->ts_nsec, text + len);

	if (len + msg->text_len > size)

		return -EINVAL;

	memcpy(text + len, log_text(msg), msg->text_len);

	len += msg->text_len;

	text[len++] = '\n';

		text = next;

	} while (text);



	return len;

}



static int syslog_print(char __user *buf, int size)

{

	char *text;

	struct log *msg;

	int len;



	text = kmalloc(LOG_LINE_MAX, GFP_KERNEL);
@@ -847,7 +872,8 @@ static int syslog_print(char __user *buf, int size) 
		syslog_seq = log_first_seq;

		syslog_idx = log_first_idx;

	}

	len = syslog_print_line(syslog_idx, text, LOG_LINE_MAX);

	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);
@@ -887,14 +913,18 @@ static int syslog_print_all(char __user *buf, int size, bool clear) 
		seq = clear_seq;

		idx = clear_idx;

		while (seq < log_next_seq) {

			len += syslog_print_line(idx, NULL, 0);

			struct log *msg = log_from_idx(idx);



			len += msg_print_text(msg, true, NULL, 0);

			idx = log_next(idx);

			seq++;

		}

		seq = clear_seq;

		idx = clear_idx;

		while (len > size && seq < log_next_seq) {

			len -= syslog_print_line(idx, NULL, 0);

			struct log *msg = log_from_idx(idx);



			len -= msg_print_text(msg, true, NULL, 0);

			idx = log_next(idx);

			seq++;

		}
@@ -904,9 +934,10 @@ static int syslog_print_all(char __user *buf, int size, bool clear) 


		len = 0;

		while (len >= 0 && seq < next_seq) {

			struct log *msg = log_from_idx(idx);

			int textlen;



			textlen = syslog_print_line(idx, text, LOG_LINE_MAX);

			textlen = msg_print_text(msg, true, text, LOG_LINE_MAX);

			if (textlen < 0) {

				len = textlen;

				break;
@@ -1044,7 +1075,9 @@ int do_syslog(int type, char __user *buf, int len, bool from_file) 
			seq = syslog_seq;

			idx = syslog_idx;

			while (seq < log_next_seq) {

				error += syslog_print_line(idx, NULL, 0);

				struct log *msg = log_from_idx(idx);



				error += msg_print_text(msg, true, NULL, 0);

				idx = log_next(idx);

				seq++;

			}
@@ -1439,10 +1472,8 @@ static struct log *log_from_idx(u32 idx) { return NULL; } 
static u32 log_next(u32 idx) { return 0; }

static char *log_text(const struct log *msg) { return NULL; }

static void call_console_drivers(int level, const char *text, size_t len) {}

static size_t prepend_timestamp(unsigned long long t, char *buf)

{

	return 0;

}

static size_t msg_print_text(const struct log *msg, bool syslog,

			     char *buf, size_t size) { return 0; }



#endif /* CONFIG_PRINTK */
@@ -1750,7 +1781,7 @@ void console_unlock(void) 
	for (;;) {

		struct log *msg;

		static char text[LOG_LINE_MAX];

		size_t len, l;

		size_t len;

		int level;



		raw_spin_lock_irqsave(&logbuf_lock, flags);
@@ -1771,13 +1802,7 @@ void console_unlock(void) 
		msg = log_from_idx(console_idx);

		level = msg->level & 7;



		len = prepend_timestamp(msg->ts_nsec, text);

		l = msg->text_len;

		if (len + l + 1 >= sizeof(text))

			l = sizeof(text) - len - 1;

		memcpy(text + len, log_text(msg), l);

		len += l;

		text[len++] = '\n';

		len = msg_print_text(msg, false, text, sizeof(text));



		console_idx = log_next(console_idx);

		console_seq++;