mirror of
https://github.com/Fishwaldo/linux-bl808.git
synced 2025-06-17 20:25:19 +00:00
kmsg - kmsg_dump() use iterator to receive log buffer content
Provide an iterator to receive the log buffer content, and convert all kmsg_dump() users to it. The structured data in the kmsg buffer now contains binary data, which should no longer be copied verbatim to the kmsg_dump() users. The iterator should provide reliable access to the buffer data, and also supports proper log line-aware chunking of data while iterating. Signed-off-by: Kay Sievers <kay@vrfy.org> Tested-by: Tony Luck <tony.luck@intel.com> Reported-by: Anton Vorontsov <anton.vorontsov@linaro.org> Tested-by: Anton Vorontsov <anton.vorontsov@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Kay Sievers
Greg Kroah-Hartman
parent
1bd289d1e8
commit
e2ae715d66
6 changed files with 264 additions and 143 deletions
232
kernel/printk.c
232
kernel/printk.c
|
|
@ -909,7 +909,7 @@ static int syslog_print_all(char __user *buf, int size, bool clear)
|
|||
/*
|
||||
* 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) {
|
||||
|
|
@ -919,6 +919,8 @@ static int syslog_print_all(char __user *buf, int size, bool clear)
|
|||
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) {
|
||||
|
|
@ -929,7 +931,7 @@ static int syslog_print_all(char __user *buf, int size, bool clear)
|
|||
seq++;
|
||||
}
|
||||
|
||||
/* last message in this dump */
|
||||
/* last message fitting into this dump */
|
||||
next_seq = log_next_seq;
|
||||
|
||||
len = 0;
|
||||
|
|
@ -2300,48 +2302,210 @@ module_param_named(always_kmsg_dump, always_kmsg_dump, bool, S_IRUGO | S_IWUSR);
|
|||
* 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. */
|
||||
|
||||
raw_spin_lock_irqsave(&logbuf_lock, flags);
|
||||
if (syslog_seq < log_first_seq)
|
||||
idx = syslog_idx;
|
||||
else
|
||||
idx = log_first_idx;
|
||||
|
||||
if (idx > log_next_idx) {
|
||||
s1 = log_buf;
|
||||
l1 = log_next_idx;
|
||||
|
||||
s2 = log_buf + idx;
|
||||
l2 = log_buf_len - idx;
|
||||
} else {
|
||||
s1 = "";
|
||||
l1 = 0;
|
||||
|
||||
s2 = log_buf + idx;
|
||||
l2 = log_next_idx - idx;
|
||||
}
|
||||
raw_spin_unlock_irqrestore(&logbuf_lock, flags);
|
||||
|
||||
rcu_read_lock();
|
||||
list_for_each_entry_rcu(dumper, &dump_list, list)
|
||||
dumper->dump(dumper, reason, s1, l1, s2, l2);
|
||||
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 (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 >= log_next_seq) {
|
||||
raw_spin_unlock_irqrestore(&logbuf_lock, flags);
|
||||
goto out;
|
||||
}
|
||||
|
||||
msg = log_from_idx(dumper->cur_idx);
|
||||
l = msg_print_text(msg, 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;
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(kmsg_dump_get_line);
|
||||
|
||||
/**
|
||||
* kmsg_dump_get_buffer - copy kmsg log lines
|
||||
* @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 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);
|
||||
|
||||
/**
|
||||
* 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
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue