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mars/kernel/brick_say.c

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// (c) 2010 Thomas Schoebel-Theuer / 1&1 Internet AG
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/string.h>
#include "brick_say.h"
#include "lamport.h"
/////////////////////////////////////////////////////////////////////
// messaging
#include <linux/fs.h>
#include <linux/blkdev.h>
#include <linux/file.h>
#include <linux/sched.h>
#include <linux/preempt.h>
#include <linux/hardirq.h>
#include <linux/smp.h>
#include <linux/slab.h>
#include <linux/kthread.h>
#include <linux/syscalls.h>
#include <asm/uaccess.h>
#ifndef GFP_BRICK
#define GFP_BRICK GFP_NOIO
#endif
#define SAY_ORDER 0
#define SAY_BUFMAX (PAGE_SIZE << SAY_ORDER)
#define SAY_BUF_LIMIT (SAY_BUFMAX - 1500)
#define MAX_FILELEN 16
#define MAX_IDS 1000
const char *say_class[MAX_SAY_CLASS] = {
[SAY_DEBUG] = "debug",
[SAY_INFO] = "info",
[SAY_WARN] = "warn",
[SAY_ERROR] = "error",
[SAY_FATAL] = "fatal",
[SAY_TOTAL] = "total",
};
EXPORT_SYMBOL_GPL(say_class);
int brick_say_logging = 1;
EXPORT_SYMBOL_GPL(brick_say_logging);
int brick_say_debug =
#ifdef CONFIG_MARS_DEBUG_DEFAULT
1;
#else
0;
#endif
EXPORT_SYMBOL_GPL(brick_say_debug);
int brick_say_syslog_min = 1;
EXPORT_SYMBOL_GPL(brick_say_syslog_min);
int brick_say_syslog_max = -1;
EXPORT_SYMBOL_GPL(brick_say_syslog_max);
int brick_say_syslog_flood_class = 3;
EXPORT_SYMBOL_GPL(brick_say_syslog_flood_class);
int brick_say_syslog_flood_limit = 20;
EXPORT_SYMBOL_GPL(brick_say_syslog_flood_limit);
int brick_say_syslog_flood_recovery = 300;
EXPORT_SYMBOL_GPL(brick_say_syslog_flood_recovery);
int delay_say_on_overflow =
#ifdef CONFIG_MARS_DEBUG
1;
#else
0;
#endif
EXPORT_SYMBOL_GPL(delay_say_on_overflow);
static atomic_t say_alloc_channels = ATOMIC_INIT(0);
static atomic_t say_alloc_names = ATOMIC_INIT(0);
static atomic_t say_alloc_pages = ATOMIC_INIT(0);
static unsigned long flood_start_jiffies = 0;
static int flood_count = 0;
struct say_channel {
char *ch_name;
struct say_channel *ch_next;
spinlock_t ch_lock[MAX_SAY_CLASS];
char *ch_buf[MAX_SAY_CLASS][2];
short ch_index[MAX_SAY_CLASS];
struct file *ch_filp[MAX_SAY_CLASS][2];
int ch_overflow[MAX_SAY_CLASS];
bool ch_written[MAX_SAY_CLASS];
bool ch_rollover;
bool ch_must_exist;
bool ch_is_dir;
bool ch_delete;
int ch_status_written;
int ch_id_max;
void *ch_ids[MAX_IDS];
wait_queue_head_t ch_progress;
};
struct say_channel *default_channel = NULL;
EXPORT_SYMBOL_GPL(default_channel);
static struct say_channel *channel_list = NULL;
static rwlock_t say_lock = __RW_LOCK_UNLOCKED(say_lock);
static struct task_struct *say_thread = NULL;
static DECLARE_WAIT_QUEUE_HEAD(say_event);
bool say_dirty = false;
static
void wait_channel(struct say_channel *ch, int class)
{
if (delay_say_on_overflow && ch->ch_index[class] > SAY_BUF_LIMIT) {
bool use_atomic = (preempt_count() & (SOFTIRQ_MASK | HARDIRQ_MASK | NMI_MASK)) != 0 || in_atomic() || irqs_disabled();
if (!use_atomic) {
say_dirty = true;
wake_up_interruptible(&say_event);
wait_event_interruptible_timeout(ch->ch_progress, ch->ch_index[class] < SAY_BUF_LIMIT, HZ / 10);
}
}
}
static
struct say_channel *find_channel(const void *id)
{
struct say_channel *res = default_channel;
struct say_channel *ch;
read_lock(&say_lock);
for (ch = channel_list; ch; ch = ch->ch_next) {
int i;
for (i = 0; i < ch->ch_id_max; i++) {
if (ch->ch_ids[i] == id) {
res = ch;
goto found;
}
}
}
found:
read_unlock(&say_lock);
return res;
}
static
void _remove_binding(struct task_struct *whom)
{
struct say_channel *ch;
int i;
for (ch = channel_list; ch; ch = ch->ch_next) {
for (i = 0; i < ch->ch_id_max; i++) {
if (ch->ch_ids[i] == whom) {
ch->ch_ids[i] = NULL;
}
}
}
}
void bind_to_channel(struct say_channel *ch, struct task_struct *whom)
{
int i;
write_lock(&say_lock);
_remove_binding(whom);
for (i = 0; i < ch->ch_id_max; i++) {
if (!ch->ch_ids[i]) {
ch->ch_ids[i] = whom;
goto done;
}
}
if (likely(ch->ch_id_max < MAX_IDS - 1)) {
ch->ch_ids[ch->ch_id_max++] = whom;
} else {
goto err;
}
done:
write_unlock(&say_lock);
return;
err:
write_unlock(&say_lock);
say_to(default_channel, SAY_ERROR, "ID overflow for thread '%s'\n", whom->comm);
}
EXPORT_SYMBOL_GPL(bind_to_channel);
struct say_channel *get_binding(struct task_struct *whom)
{
struct say_channel *ch;
int i;
read_lock(&say_lock);
for (ch = channel_list; ch; ch = ch->ch_next) {
for (i = 0; i < ch->ch_id_max; i++) {
if (ch->ch_ids[i] == whom) {
goto found;
}
}
}
ch = NULL;
found:
read_unlock(&say_lock);
return ch;
}
EXPORT_SYMBOL_GPL(get_binding);
void remove_binding_from(struct say_channel *ch, struct task_struct *whom)
{
bool found = false;
int i;
write_lock(&say_lock);
for (i = 0; i < ch->ch_id_max; i++) {
if (ch->ch_ids[i] == whom) {
ch->ch_ids[i] = NULL;
found = true;
break;
}
}
if (!found) {
_remove_binding(whom);
}
write_unlock(&say_lock);
}
EXPORT_SYMBOL_GPL(remove_binding_from);
void remove_binding(struct task_struct *whom)
{
write_lock(&say_lock);
_remove_binding(whom);
write_unlock(&say_lock);
}
EXPORT_SYMBOL_GPL(remove_binding);
void rollover_channel(struct say_channel *ch)
{
if (!ch) {
ch = find_channel(current);
}
if (likely(ch))
ch->ch_rollover = true;
}
EXPORT_SYMBOL_GPL(rollover_channel);
void rollover_all(void)
{
struct say_channel *ch;
read_lock(&say_lock);
for (ch = channel_list; ch; ch = ch->ch_next) {
ch->ch_rollover = true;
}
read_unlock(&say_lock);
}
EXPORT_SYMBOL_GPL(rollover_all);
void del_channel(struct say_channel *ch)
{
if (unlikely(!ch))
return;
if (unlikely(ch == default_channel)) {
say_to(default_channel, SAY_ERROR, "thread '%s' tried to delete the default channel\n", current->comm);
return;
}
ch->ch_delete = true;
}
EXPORT_SYMBOL_GPL(del_channel);
static
void _del_channel(struct say_channel *ch)
{
struct say_channel *tmp;
struct say_channel **_tmp;
int i, j;
if (!ch)
return;
write_lock(&say_lock);
for (_tmp = &channel_list; (tmp = *_tmp) != NULL; _tmp = &tmp->ch_next) {
if (tmp == ch) {
*_tmp = tmp->ch_next;
break;
}
}
write_unlock(&say_lock);
for (i = 0; i < MAX_SAY_CLASS; i++) {
for (j = 0; j < 2; j++) {
if (ch->ch_filp[i][j]) {
filp_close(ch->ch_filp[i][j], NULL);
ch->ch_filp[i][j] = NULL;
}
}
for (j = 0; j < 2; j++) {
char *buf = ch->ch_buf[i][j];
if (buf) {
__free_pages(virt_to_page((unsigned long)buf), SAY_ORDER);
atomic_dec(&say_alloc_pages);
}
}
}
if (ch->ch_name) {
kfree(ch->ch_name);
atomic_dec(&say_alloc_names);
}
kfree(ch);
atomic_dec(&say_alloc_channels);
}
static
struct say_channel *_make_channel(const char *name, bool must_exist)
{
struct say_channel *res = NULL;
struct kstat kstat = {};
int i, j;
bool use_atomic = (preempt_count() & (SOFTIRQ_MASK | HARDIRQ_MASK | NMI_MASK)) != 0 || in_atomic() || irqs_disabled();
unsigned long mode = use_atomic ? GFP_ATOMIC : GFP_BRICK;
mm_segment_t oldfs;
bool is_dir = false;
int status;
oldfs = get_fs();
set_fs(get_ds());
status = vfs_stat((char*)name, &kstat);
set_fs(oldfs);
if (unlikely(status < 0)) {
if (must_exist) {
say(SAY_ERROR, "cannot create channel '%s', status = %d\n", name, status);
goto done;
}
} else {
is_dir = S_ISDIR(kstat.mode);
}
restart:
res = kzalloc(sizeof(struct say_channel), mode);
if (unlikely(!res)) {
schedule();
goto restart;
}
atomic_inc(&say_alloc_channels);
res->ch_must_exist = must_exist;
res->ch_is_dir = is_dir;
init_waitqueue_head(&res->ch_progress);
restart2:
res->ch_name = kstrdup(name, mode);
if (unlikely(!res->ch_name)) {
schedule();
goto restart2;
}
atomic_inc(&say_alloc_names);
for (i = 0; i < MAX_SAY_CLASS; i++) {
spin_lock_init(&res->ch_lock[i]);
for (j = 0; j < 2; j++) {
char *buf;
restart3:
buf = (void*)__get_free_pages(mode, SAY_ORDER);
if (unlikely(!buf)) {
schedule();
goto restart3;
}
atomic_inc(&say_alloc_pages);
res->ch_buf[i][j] = buf;
}
}
done:
return res;
}
struct say_channel *make_channel(const char *name, bool must_exist)
{
struct say_channel *res = NULL;
struct say_channel *ch;
read_lock(&say_lock);
for (ch = channel_list; ch; ch = ch->ch_next) {
if (!strcmp(ch->ch_name, name)) {
res = ch;
break;
}
}
read_unlock(&say_lock);
if (unlikely(!res)) {
res = _make_channel(name, must_exist);
if (unlikely(!res))
goto done;
write_lock(&say_lock);
for (ch = channel_list; ch; ch = ch->ch_next) {
if (ch != res && unlikely(!strcmp(ch->ch_name, name))) {
_del_channel(res);
res = ch;
goto race_found;
}
}
res->ch_next = channel_list;
channel_list = res;
race_found:
write_unlock(&say_lock);
}
done:
return res;
}
EXPORT_SYMBOL_GPL(make_channel);
// tell gcc to check for varargs errors
static
void _say(struct say_channel *ch, int class, va_list args, bool use_args, const char *fmt, ...) __attribute__ ((format (printf, 5, 6)));
static
void _say(struct say_channel *ch, int class, va_list args, bool use_args, const char *fmt, ...)
{
char *start;
int offset;
int rest;
int written;
if (unlikely(!ch))
return;
if (unlikely(ch->ch_delete && ch != default_channel)) {
say_to(default_channel, SAY_ERROR, "thread '%s' tried to write on deleted channel\n", current->comm);
return;
}
offset = ch->ch_index[class];
start = ch->ch_buf[class][0] + offset;
rest = SAY_BUFMAX - 1 - offset;
if (unlikely(rest <= 0)) {
ch->ch_overflow[class]++;
return;
}
if (use_args) {
va_list args2;
va_start(args2, fmt);
written = vscnprintf(start, rest, fmt, args2);
va_end(args2);
} else {
written = vscnprintf(start, rest, fmt, args);
}
if (likely(rest > written)) {
start[written] = '\0';
ch->ch_index[class] += written;
say_dirty = true;
} else {
// indicate overflow
start[0] = '\0';
ch->ch_overflow[class]++;
}
}
void say_to(struct say_channel *ch, int class, const char *fmt, ...)
{
va_list args;
unsigned long flags;
if (!class && !brick_say_debug)
return;
if (!ch) {
ch = find_channel(current);
}
if (likely(ch)) {
if (!ch->ch_is_dir)
class = SAY_TOTAL;
if (likely(class >= 0 && class < MAX_SAY_CLASS)) {
wait_channel(ch, class);
spin_lock_irqsave(&ch->ch_lock[class], flags);
va_start(args, fmt);
_say(ch, class, args, false, fmt);
va_end(args);
spin_unlock_irqrestore(&ch->ch_lock[class], flags);
}
}
ch = default_channel;
if (likely(ch)) {
class = SAY_TOTAL;
wait_channel(ch, class);
spin_lock_irqsave(&ch->ch_lock[class], flags);
va_start(args, fmt);
_say(ch, class, args, false, fmt);
va_end(args);
spin_unlock_irqrestore(&ch->ch_lock[class], flags);
wake_up_interruptible(&say_event);
}
}
EXPORT_SYMBOL_GPL(say_to);
void brick_say_to(struct say_channel *ch, int class, bool dump, const char *prefix, const char *file, int line, const char *func, const char *fmt, ...)
{
const char *channel_name = "-";
struct timespec s_now;
struct timespec l_now;
int filelen;
int orig_class;
va_list args;
unsigned long flags;
if (!class && !brick_say_debug)
return;
s_now = CURRENT_TIME;
get_lamport(&l_now);
if (!ch) {
ch = find_channel(current);
}
orig_class = class;
// limit the filename
filelen = strlen(file);
if (filelen > MAX_FILELEN)
file += filelen - MAX_FILELEN;
if (likely(ch)) {
channel_name = ch->ch_name;
if (!ch->ch_is_dir)
class = SAY_TOTAL;
if (likely(class >= 0 && class < MAX_SAY_CLASS)) {
wait_channel(ch, class);
spin_lock_irqsave(&ch->ch_lock[class], flags);
_say(ch, class, NULL, true,
"%ld.%09ld %ld.%09ld %s %s[%d] %s:%d %s(): ",
s_now.tv_sec, s_now.tv_nsec,
l_now.tv_sec, l_now.tv_nsec,
prefix,
current->comm, (int)smp_processor_id(),
file, line,
func);
va_start(args, fmt);
_say(ch, class, args, false, fmt);
va_end(args);
spin_unlock_irqrestore(&ch->ch_lock[class], flags);
}
}
ch = default_channel;
if (likely(ch)) {
wait_channel(ch, SAY_TOTAL);
spin_lock_irqsave(&ch->ch_lock[SAY_TOTAL], flags);
_say(ch, SAY_TOTAL, NULL, true,
"%ld.%09ld %ld.%09ld %s_%-5s %s %s[%d] %s:%d %s(): ",
s_now.tv_sec, s_now.tv_nsec,
l_now.tv_sec, l_now.tv_nsec,
prefix, say_class[orig_class],
channel_name,
current->comm, (int)smp_processor_id(),
file, line,
func);
va_start(args, fmt);
_say(ch, SAY_TOTAL, args, false, fmt);
va_end(args);
spin_unlock_irqrestore(&ch->ch_lock[SAY_TOTAL], flags);
}
#ifdef CONFIG_MARS_DEBUG
if (dump)
brick_dump_stack();
#endif
wake_up_interruptible(&say_event);
}
EXPORT_SYMBOL_GPL(brick_say_to);
static
void try_open_file(struct file **file, char *filename, bool creat)
{
struct address_space *mapping;
int flags = O_APPEND | O_WRONLY | O_LARGEFILE;
int prot = 0600;
if (creat)
flags |= O_CREAT;
*file = filp_open(filename, flags, prot);
if (unlikely(IS_ERR(*file))) {
*file = NULL;
} else if ((mapping = (*file)->f_mapping)) {
mapping_set_gfp_mask(mapping, mapping_gfp_mask(mapping) & ~(__GFP_IO | __GFP_FS));
}
}
static
void out_to_file(struct file *file, char *buf, int len)
{
loff_t log_pos = 0;
mm_segment_t oldfs;
if (file) {
oldfs = get_fs();
set_fs(get_ds());
(void)vfs_write(file, buf, len, &log_pos);
set_fs(oldfs);
}
}
static inline
void reset_flood(void)
{
if (flood_start_jiffies &&
(long)jiffies >= (long)(flood_start_jiffies + brick_say_syslog_flood_recovery * HZ)) {
flood_start_jiffies = 0;
flood_count = 0;
}
}
static
void out_to_syslog(int class, char *buf, int len)
{
reset_flood();
if (class >= brick_say_syslog_min && class <= brick_say_syslog_max) {
buf[len] = '\0';
printk("%s", buf);
} else if (class >= brick_say_syslog_flood_class && brick_say_syslog_flood_class >= 0 && class != SAY_TOTAL) {
flood_start_jiffies = jiffies;
if (++flood_count <= brick_say_syslog_flood_limit) {
buf[len] = '\0';
printk("%s", buf);
}
}
}
static inline
char *_make_filename(struct say_channel *ch, int class, int transact, int add_tmp)
{
char *filename;
restart:
filename = kmalloc(1024, GFP_KERNEL);
if (unlikely(!filename)) {
schedule();
goto restart;
}
atomic_inc(&say_alloc_names);
if (ch->ch_is_dir) {
snprintf(filename, 1023, "%s/%d.%s.%s%s", ch->ch_name, class, say_class[class], transact ? "status" : "log", add_tmp ? ".tmp" : "");
} else {
snprintf(filename, 1023, "%s.%s%s", ch->ch_name, transact ? "status" : "log", add_tmp ? ".tmp" : "");
}
return filename;
}
static
void _rollover_channel(struct say_channel *ch)
{
int start = 0;
int class;
ch->ch_rollover = false;
ch->ch_status_written = 0;
if (!ch->ch_is_dir)
start = SAY_TOTAL;
for (class = start; class < MAX_SAY_CLASS; class++) {
char *old = _make_filename(ch, class, 1, 1);
char *new = _make_filename(ch, class, 1, 0);
if (likely(old && new)) {
int i;
mm_segment_t oldfs;
for (i = 0; i < 2; i++) {
if (ch->ch_filp[class][i]) {
filp_close(ch->ch_filp[class][i], NULL);
ch->ch_filp[class][i] = NULL;
}
}
oldfs = get_fs();
set_fs(get_ds());
sys_rename(old, new);
set_fs(oldfs);
}
if (likely(old)) {
kfree(old);
atomic_dec(&say_alloc_names);
}
if (likely(new)) {
kfree(new);
atomic_dec(&say_alloc_names);
}
}
}
static
void treat_channel(struct say_channel *ch, int class)
{
int len;
int overflow;
int transact;
int start;
char *buf;
char *tmp;
unsigned long flags;
spin_lock_irqsave(&ch->ch_lock[class], flags);
buf = ch->ch_buf[class][0];
tmp = ch->ch_buf[class][1];
ch->ch_buf[class][1] = buf;
ch->ch_buf[class][0] = tmp;
len = ch->ch_index[class];
ch->ch_index[class] = 0;
overflow = ch->ch_overflow[class];
ch->ch_overflow[class] = 0;
spin_unlock_irqrestore(&ch->ch_lock[class], flags);
wake_up_interruptible(&ch->ch_progress);
ch->ch_status_written += len;
out_to_syslog(class, buf, len);
start = 0;
if (!brick_say_logging)
start++;
for (transact = start; transact < 2; transact++) {
if (unlikely(!ch->ch_filp[class][transact])) {
char *filename = _make_filename(ch, class, transact, transact);
if (likely(filename)) {
try_open_file(&ch->ch_filp[class][transact], filename, transact);
kfree(filename);
atomic_dec(&say_alloc_names);
}
}
out_to_file(ch->ch_filp[class][transact], buf, len);
}
if (unlikely(overflow > 0)) {
struct timespec s_now = CURRENT_TIME;
struct timespec l_now;
get_lamport(&l_now);
len = scnprintf(buf,
SAY_BUFMAX,
"%ld.%09ld %ld.%09ld %s %d OVERFLOW %d times\n",
s_now.tv_sec, s_now.tv_nsec,
l_now.tv_sec, l_now.tv_nsec,
ch->ch_name,
class,
overflow);
ch->ch_status_written += len;
out_to_syslog(class, buf, len);
for (transact = 0; transact < 2; transact++) {
out_to_file(ch->ch_filp[class][transact], buf, len);
}
}
}
static
int _say_thread(void *data)
{
while (!kthread_should_stop()) {
struct say_channel *ch;
int i;
wait_event_interruptible_timeout(say_event, say_dirty, HZ);
say_dirty = false;
restart_rollover:
read_lock(&say_lock);
for (ch = channel_list; ch; ch = ch->ch_next) {
if (ch->ch_rollover && ch->ch_status_written > 0) {
read_unlock(&say_lock);
_rollover_channel(ch);
goto restart_rollover;
}
}
read_unlock(&say_lock);
restart:
read_lock(&say_lock);
for (ch = channel_list; ch; ch = ch->ch_next) {
int start = 0;
if (!ch->ch_is_dir)
start = SAY_TOTAL;
for (i = start; i < MAX_SAY_CLASS; i++) {
if (ch->ch_index[i] > 0) {
read_unlock(&say_lock);
treat_channel(ch, i);
goto restart;
}
}
if (ch->ch_delete) {
read_unlock(&say_lock);
_del_channel(ch);
goto restart;
}
}
read_unlock(&say_lock);
}
return 0;
}
void init_say(void)
{
default_channel = make_channel(CONFIG_MARS_LOGDIR, true);
say_thread = kthread_create(_say_thread, NULL, "brick_say");
if (IS_ERR(say_thread)) {
say_thread = NULL;
} else {
get_task_struct(say_thread);
wake_up_process(say_thread);
}
}
EXPORT_SYMBOL_GPL(init_say);
void exit_say(void)
{
int memleak_channels;
int memleak_names;
int memleak_pages;
if (say_thread) {
kthread_stop(say_thread);
put_task_struct(say_thread);
say_thread = NULL;
}
default_channel = NULL;
while (channel_list) {
_del_channel(channel_list);
}
memleak_channels = atomic_read(&say_alloc_channels);
memleak_names = atomic_read(&say_alloc_names);
memleak_pages = atomic_read(&say_alloc_pages);
if (unlikely(memleak_channels || memleak_names || memleak_pages)) {
printk("MEMLEAK: channels=%d names=%d pages=%d\n", memleak_channels, memleak_names, memleak_pages);
}
}
EXPORT_SYMBOL_GPL(exit_say);
#ifdef CONFIG_MARS_DEBUG
static int dump_max = 5;
void brick_dump_stack(void)
{
if (dump_max > 0) {
dump_max--; // racy, but does no harm
dump_stack();
}
}
EXPORT_SYMBOL(brick_dump_stack);
#endif
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