Skip to content

Commit

Permalink
printk() - restore prefix/timestamp printing for multi-newline strings
Browse files Browse the repository at this point in the history 
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>
  • Loading branch information
Kay Sievers authored and Greg Kroah-Hartman committed May 14, 2012
1 parent 1fce677 commit 3ce9a7c
Showing 1 changed file with 76 additions and 51 deletions.
127 changes: 76 additions & 51 deletions kernel/printk.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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);
Expand All @@ -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++] = ' ';
Expand Down Expand Up @@ -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;
}

text = next;
} while (text);

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';
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);
Expand All @@ -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);
Expand Down Expand Up @@ -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++;
}
Expand All @@ -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;
Expand Down Expand Up @@ -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++;
}
Expand Down Expand Up @@ -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 */

Expand Down Expand Up @@ -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);
Expand All @@ -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++;
Expand Down

0 comments on commit 3ce9a7c

Please sign in to comment.