include/net/netfilter/xt_log.h

   1 #define S_SIZE (1024 - (sizeof(unsigned int) + 1))
   2
   3 struct sbuff {
   4         unsigned int    count;
   5         char            buf[S_SIZE + 1];
   6 };
   7 static struct sbuff emergency, *emergency_ptr = &emergency;
   8
   9 static int sb_add(struct sbuff *m, const char *f, ...)
  10 {
  11         va_list args;
  12         int len;
  13
  14         if (likely(m->count < S_SIZE)) {
  15                 va_start(args, f);
  16                 len = vsnprintf(m->buf + m->count, S_SIZE - m->count, f, args);
  17                 va_end(args);
  18                 if (likely(m->count + len < S_SIZE)) {
  19                         m->count += len;
  20                         return 0;
  21                 }
  22         }
  23         m->count = S_SIZE;
  24         printk_once(KERN_ERR KBUILD_MODNAME " please increase S_SIZE\n");
  25         return -1;
  26 }
  27
  28 static struct sbuff *sb_open(void)
  29 {
  30         struct sbuff *m = kmalloc(sizeof(*m), GFP_ATOMIC);
  31
  32         if (unlikely(!m)) {
  33                 local_bh_disable();
  34                 do {
  35                         m = xchg(&emergency_ptr, NULL);
  36                 } while (!m);
  37         }
  38         m->count = 0;
  39         return m;
  40 }
  41
  42 static void sb_close(struct sbuff *m)
  43 {
  44         m->buf[m->count] = 0;
  45         printk("%s\n", m->buf);
  46
  47         if (likely(m != &emergency))
  48                 kfree(m);
  49         else {
  50                 xchg(&emergency_ptr, m);
  51                 local_bh_enable();
  52         }
  53 }
  54