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: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Kay Sievers <kay@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/kernel/printk.c b/kernel/printk.c
index c42faf9..915a8be 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -448,7 +448,7 @@
/* 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 @@
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 @@
#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 (!buf)
- return 15;
-
- rem_ns = do_div(t, 1000000000);
-
- return sprintf(buf, "[%5lu.%06lu] ",
- (unsigned long) t, rem_ns / 1000);
-}
-
-static int syslog_print_line(u32 idx, char *text, size_t size)
-{
- struct log *msg;
- size_t len;
-
- msg = log_from_idx(idx);
- if (!text) {
- /* calculate length only */
- len = 3;
-
- if (msg->level > 9)
- len++;
- if (msg->level > 99)
- len++;
- len += prepend_timestamp(0, NULL);
-
- len += msg->text_len;
- len++;
- return len;
+ if (syslog) {
+ if (buf) {
+ len += sprintf(buf, "<%u>", msg->level);
+ } else {
+ len += 3;
+ if (msg->level > 9)
+ len++;
+ if (msg->level > 99)
+ len++;
+ }
}
- 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';
+ 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;
+ }
+ }
+
+ return len;
+}
+
+static size_t msg_print_text(const struct log *msg, bool syslog,
+ char *buf, size_t size)
+{
+ const char *text = log_text(msg);
+ size_t text_size = msg->text_len;
+ size_t len = 0;
+
+ do {
+ const char *next = memchr(text, '\n', text_size);
+ size_t text_len;
+
+ if (next) {
+ text_len = next - text;
+ next++;
+ text_size -= next - text;
+ } else {
+ text_len = text_size;
+ }
+
+ 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;
+ }
+
+ 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 @@
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 @@
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 @@
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 @@
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 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 @@
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 @@
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++;
