Containerized syslog working properly
[safe/jmp/linux-2.6] / kernel / printk.c
index 75077ad..7f60d8a 100644 (file)
@@ -52,8 +52,6 @@ void asmlinkage __attribute__((weak)) early_printk(const char *fmt, ...)
 {
 }
 
-#define __LOG_BUF_LEN  (1 << CONFIG_LOG_BUF_SHIFT)
-
 /* printk's without a loglevel use this.. */
 #define DEFAULT_MESSAGE_LOGLEVEL 4 /* KERN_WARNING */
 
@@ -96,23 +94,19 @@ EXPORT_SYMBOL_GPL(console_drivers);
  */
 static int console_locked, console_suspended;
 
-/*
- * logbuf_lock protects log_buf, log_start, log_end, con_start and logged_chars
- * It is also used in interesting ways to provide interlocking in
- * release_console_sem().
- */
-static DEFINE_SPINLOCK(logbuf_lock);
-
-#define LOG_BUF_MASK (log_buf_len-1)
-#define LOG_BUF(idx) (log_buf[(idx) & LOG_BUF_MASK])
+#define LOG_BUF_MASK(ns) ((ns)->buf_len-1)
+#define LOG_BUF(ns, idx) ((ns)->buf[(idx) & LOG_BUF_MASK(ns)])
 
 /*
- * The indices into log_buf are not constrained to log_buf_len - they
- * must be masked before subscripting
+ * To access container syslog ring buffer
  */
-static unsigned log_start;     /* Index into log_buf: next char to be read by syslog() */
-static unsigned con_start;     /* Index into log_buf: next char to be sent to consoles */
-static unsigned log_end;       /* Index into log_buf: most-recently-written-char + 1 */
+#define sys_log_lock (syslog_ns->logbuf_lock)
+#define sys_log_start (syslog_ns->log_start)
+#define sys_log_end (syslog_ns->log_end)
+#define sys_log_con_start (syslog_ns->con_start)
+#define sys_log_buf_len (syslog_ns->buf_len)
+#define sys_log_logged_chars (syslog_ns->logged_chars)
+#define sys_log_buf (syslog_ns->buf)
 
 /*
  *     Array of consoles built from command line options (console=)
@@ -140,10 +134,6 @@ static int console_may_schedule;
 
 #ifdef CONFIG_PRINTK
 
-static char __log_buf[__LOG_BUF_LEN];
-static char *log_buf = __log_buf;
-static int log_buf_len = __LOG_BUF_LEN;
-static unsigned logged_chars; /* Number of chars produced since last read+clear operation */
 static int saved_console_loglevel = -1;
 
 #ifdef CONFIG_KEXEC
@@ -157,49 +147,23 @@ static int saved_console_loglevel = -1;
  */
 void log_buf_kexec_setup(void)
 {
-       VMCOREINFO_SYMBOL(log_buf);
-       VMCOREINFO_SYMBOL(log_end);
-       VMCOREINFO_SYMBOL(log_buf_len);
-       VMCOREINFO_SYMBOL(logged_chars);
+       struct syslog_ns *syslog_ns = current_syslog_ns();
+
+       VMCOREINFO_SYMBOL(sys_log_buf);
+       VMCOREINFO_SYMBOL(sys_log_end);
+       VMCOREINFO_SYMBOL(sys_log_buf_len);
+       VMCOREINFO_SYMBOL(sys_log_logged_chars);
 }
 #endif
 
 static int __init log_buf_len_setup(char *str)
 {
        unsigned size = memparse(str, &str);
-       unsigned long flags;
 
-       if (size)
+       if (size) {
                size = roundup_pow_of_two(size);
-       if (size > log_buf_len) {
-               unsigned start, dest_idx, offset;
-               char *new_log_buf;
-
-               new_log_buf = alloc_bootmem(size);
-               if (!new_log_buf) {
-                       printk(KERN_WARNING "log_buf_len: allocation failed\n");
-                       goto out;
-               }
-
-               spin_lock_irqsave(&logbuf_lock, flags);
-               log_buf_len = size;
-               log_buf = new_log_buf;
-
-               offset = start = min(con_start, log_start);
-               dest_idx = 0;
-               while (start != log_end) {
-                       log_buf[dest_idx] = __log_buf[start & (__LOG_BUF_LEN - 1)];
-                       start++;
-                       dest_idx++;
-               }
-               log_start -= offset;
-               con_start -= offset;
-               log_end -= offset;
-               spin_unlock_irqrestore(&logbuf_lock, flags);
-
-               printk(KERN_NOTICE "log_buf_len: %d\n", log_buf_len);
+               resize_syslog_ns(&init_syslog_ns, size);
        }
-out:
        return 1;
 }
 
@@ -264,6 +228,7 @@ int do_syslog(int type, char __user *buf, int len, bool from_file)
        int do_clear = 0;
        char c;
        int error = 0;
+       struct syslog_ns *syslog_ns = current_syslog_ns();
 
        error = security_syslog(type, from_file);
        if (error)
@@ -286,22 +251,22 @@ int do_syslog(int type, char __user *buf, int len, bool from_file)
                        goto out;
                }
                error = wait_event_interruptible(log_wait,
-                                                       (log_start - log_end));
+                                       (sys_log_start - sys_log_end));
                if (error)
                        goto out;
                i = 0;
-               spin_lock_irq(&logbuf_lock);
-               while (!error && (log_start != log_end) && i < len) {
-                       c = LOG_BUF(log_start);
-                       log_start++;
-                       spin_unlock_irq(&logbuf_lock);
+               spin_lock_irq(&sys_log_lock);
+               while (!error && (sys_log_start != sys_log_end) && i < len) {
+                       c = LOG_BUF(syslog_ns, sys_log_start);
+                       sys_log_start++;
+                       spin_unlock_irq(&sys_log_lock);
                        error = __put_user(c,buf);
                        buf++;
                        i++;
                        cond_resched();
-                       spin_lock_irq(&logbuf_lock);
+                       spin_lock_irq(&sys_log_lock);
                }
-               spin_unlock_irq(&logbuf_lock);
+               spin_unlock_irq(&sys_log_lock);
                if (!error)
                        error = i;
                break;
@@ -322,14 +287,14 @@ int do_syslog(int type, char __user *buf, int len, bool from_file)
                        goto out;
                }
                count = len;
-               if (count > log_buf_len)
-                       count = log_buf_len;
-               spin_lock_irq(&logbuf_lock);
-               if (count > logged_chars)
-                       count = logged_chars;
+               if (count > sys_log_buf_len)
+                       count = sys_log_buf_len;
+               spin_lock_irq(&sys_log_lock);
+               if (count > sys_log_logged_chars)
+                       count = sys_log_logged_chars;
                if (do_clear)
-                       logged_chars = 0;
-               limit = log_end;
+                       sys_log_logged_chars = 0;
+               limit = sys_log_end;
                /*
                 * __put_user() could sleep, and while we sleep
                 * printk() could overwrite the messages
@@ -338,15 +303,15 @@ int do_syslog(int type, char __user *buf, int len, bool from_file)
                 */
                for (i = 0; i < count && !error; i++) {
                        j = limit-1-i;
-                       if (j + log_buf_len < log_end)
+                       if (j + sys_log_buf_len < sys_log_end)
                                break;
-                       c = LOG_BUF(j);
-                       spin_unlock_irq(&logbuf_lock);
+                       c = LOG_BUF(syslog_ns, j);
+                       spin_unlock_irq(&sys_log_lock);
                        error = __put_user(c,&buf[count-1-i]);
                        cond_resched();
-                       spin_lock_irq(&logbuf_lock);
+                       spin_lock_irq(&sys_log_lock);
                }
-               spin_unlock_irq(&logbuf_lock);
+               spin_unlock_irq(&sys_log_lock);
                if (error)
                        break;
                error = i;
@@ -365,7 +330,7 @@ int do_syslog(int type, char __user *buf, int len, bool from_file)
                break;
        /* Clear ring buffer */
        case SYSLOG_ACTION_CLEAR:
-               logged_chars = 0;
+               sys_log_logged_chars = 0;
                break;
        /* Disable logging to console */
        case SYSLOG_ACTION_CONSOLE_OFF:
@@ -394,11 +359,11 @@ int do_syslog(int type, char __user *buf, int len, bool from_file)
                break;
        /* Number of chars in the log buffer */
        case SYSLOG_ACTION_SIZE_UNREAD:
-               error = log_end - log_start;
+               error = sys_log_end - sys_log_start;
                break;
        /* Size of the log buffer */
        case SYSLOG_ACTION_SIZE_BUFFER:
-               error = log_buf_len;
+               error = sys_log_buf_len;
                break;
        default:
                error = -EINVAL;
@@ -416,7 +381,8 @@ SYSCALL_DEFINE3(syslog, int, type, char __user *, buf, int, len)
 /*
  * Call the console drivers on a range of log_buf
  */
-static void __call_console_drivers(unsigned start, unsigned end)
+static void __call_console_drivers(struct syslog_ns *syslog_ns,
+                               unsigned start, unsigned end)
 {
        struct console *con;
 
@@ -424,7 +390,8 @@ static void __call_console_drivers(unsigned start, unsigned end)
                if ((con->flags & CON_ENABLED) && con->write &&
                                (cpu_online(smp_processor_id()) ||
                                (con->flags & CON_ANYTIME)))
-                       con->write(con, &LOG_BUF(start), end - start);
+                       con->write(con, &LOG_BUF(syslog_ns, start),
+                               end - start);
        }
 }
 
@@ -443,18 +410,21 @@ early_param("ignore_loglevel", ignore_loglevel_setup);
 /*
  * Write out chars from start to end - 1 inclusive
  */
-static void _call_console_drivers(unsigned start,
-                               unsigned end, int msg_log_level)
+static void _call_console_drivers(struct syslog_ns *syslog_ns, unsigned start,
+                                 unsigned end, int msg_log_level)
 {
        if ((msg_log_level < console_loglevel || ignore_loglevel) &&
                        console_drivers && start != end) {
-               if ((start & LOG_BUF_MASK) > (end & LOG_BUF_MASK)) {
+               if ((start & LOG_BUF_MASK(syslog_ns)) >
+                       (end & LOG_BUF_MASK(syslog_ns))) {
                        /* wrapped write */
-                       __call_console_drivers(start & LOG_BUF_MASK,
-                                               log_buf_len);
-                       __call_console_drivers(0, end & LOG_BUF_MASK);
+                       __call_console_drivers(syslog_ns,
+                                       start & LOG_BUF_MASK(syslog_ns),
+                                       sys_log_buf_len);
+                       __call_console_drivers(syslog_ns, 0,
+                                       end & LOG_BUF_MASK(syslog_ns));
                } else {
-                       __call_console_drivers(start, end);
+                       __call_console_drivers(syslog_ns, start, end);
                }
        }
 }
@@ -464,7 +434,8 @@ static void _call_console_drivers(unsigned start,
  * log_buf[start] to log_buf[end - 1].
  * The console_sem must be held.
  */
-static void call_console_drivers(unsigned start, unsigned end)
+static void call_console_drivers(struct syslog_ns *syslog_ns,
+                               unsigned start, unsigned end)
 {
        unsigned cur_index, start_print;
        static int msg_level = -1;
@@ -475,16 +446,16 @@ static void call_console_drivers(unsigned start, unsigned end)
        start_print = start;
        while (cur_index != end) {
                if (msg_level < 0 && ((end - cur_index) > 2) &&
-                               LOG_BUF(cur_index + 0) == '<' &&
-                               LOG_BUF(cur_index + 1) >= '0' &&
-                               LOG_BUF(cur_index + 1) <= '7' &&
-                               LOG_BUF(cur_index + 2) == '>') {
-                       msg_level = LOG_BUF(cur_index + 1) - '0';
+                               LOG_BUF(syslog_ns, cur_index + 0) == '<' &&
+                               LOG_BUF(syslog_ns, cur_index + 1) >= '0' &&
+                               LOG_BUF(syslog_ns, cur_index + 1) <= '7' &&
+                               LOG_BUF(syslog_ns, cur_index + 2) == '>') {
+                       msg_level = LOG_BUF(syslog_ns, cur_index + 1) - '0';
                        cur_index += 3;
                        start_print = cur_index;
                }
                while (cur_index != end) {
-                       char c = LOG_BUF(cur_index);
+                       char c = LOG_BUF(syslog_ns, cur_index);
 
                        cur_index++;
                        if (c == '\n') {
@@ -497,26 +468,27 @@ static void call_console_drivers(unsigned start, unsigned end)
                                         */
                                        msg_level = default_message_loglevel;
                                }
-                               _call_console_drivers(start_print, cur_index, msg_level);
+                               _call_console_drivers(syslog_ns,
+                                       start_print, cur_index, msg_level);
                                msg_level = -1;
                                start_print = cur_index;
                                break;
                        }
                }
        }
-       _call_console_drivers(start_print, end, msg_level);
+       _call_console_drivers(syslog_ns, start_print, end, msg_level);
 }
 
-static void emit_log_char(char c)
+static void emit_log_char(struct syslog_ns *syslog_ns, char c)
 {
-       LOG_BUF(log_end) = c;
-       log_end++;
-       if (log_end - log_start > log_buf_len)
-               log_start = log_end - log_buf_len;
-       if (log_end - con_start > log_buf_len)
-               con_start = log_end - log_buf_len;
-       if (logged_chars < log_buf_len)
-               logged_chars++;
+       LOG_BUF(syslog_ns, sys_log_end) = c;
+       sys_log_end++;
+       if (sys_log_end - sys_log_start > sys_log_buf_len)
+               sys_log_start = sys_log_end - sys_log_buf_len;
+       if (sys_log_end - sys_log_con_start > sys_log_buf_len)
+               sys_log_con_start = sys_log_end - sys_log_buf_len;
+       if (sys_log_logged_chars < sys_log_buf_len)
+               sys_log_logged_chars++;
 }
 
 /*
@@ -524,7 +496,7 @@ static void emit_log_char(char c)
  * every 10 seconds, to leave time for slow consoles to print a
  * full oops.
  */
-static void zap_locks(void)
+static void zap_locks(struct syslog_ns *syslog_ns)
 {
        static unsigned long oops_timestamp;
 
@@ -535,7 +507,7 @@ static void zap_locks(void)
        oops_timestamp = jiffies;
 
        /* If a crash is occurring, make sure we can't deadlock */
-       spin_lock_init(&logbuf_lock);
+       spin_lock_init(&sys_log_lock);
        /* And make sure that we print immediately */
        init_MUTEX(&console_sem);
 }
@@ -619,7 +591,8 @@ static inline int can_use_console(unsigned int cpu)
  * interrupts disabled. It should return with 'lockbuf_lock'
  * released but interrupts still disabled.
  */
-static int acquire_console_semaphore_for_printk(unsigned int cpu)
+static int acquire_console_semaphore_for_printk(
+               struct syslog_ns *syslog_ns, unsigned int cpu)
 {
        int retval = 0;
 
@@ -639,7 +612,7 @@ static int acquire_console_semaphore_for_printk(unsigned int cpu)
                }
        }
        printk_cpu = UINT_MAX;
-       spin_unlock(&logbuf_lock);
+       spin_unlock(&sys_log_lock);
        return retval;
 }
 static const char recursion_bug_msg [] =
@@ -666,6 +639,7 @@ asmlinkage int vprintk(const char *fmt, va_list args)
 {
        int printed_len = 0;
        int current_log_level = default_message_loglevel;
+       struct syslog_ns *syslog_ns = current_syslog_ns();
        unsigned long flags;
        int this_cpu;
        char *p;
@@ -693,11 +667,11 @@ asmlinkage int vprintk(const char *fmt, va_list args)
                        recursion_bug = 1;
                        goto out_restore_irqs;
                }
-               zap_locks();
+               zap_locks(syslog_ns);
        }
 
        lockdep_off();
-       spin_lock(&logbuf_lock);
+       spin_lock(&sys_log_lock);
        printk_cpu = this_cpu;
 
        if (recursion_bug) {
@@ -722,7 +696,7 @@ asmlinkage int vprintk(const char *fmt, va_list args)
                        /* Fallthrough - make sure we're on a new line */
                        case 'd': /* KERN_DEFAULT */
                                if (!new_text_line) {
-                                       emit_log_char('\n');
+                                       emit_log_char(syslog_ns, '\n');
                                        new_text_line = 1;
                                }
                        /* Fallthrough - skip the loglevel */
@@ -740,9 +714,9 @@ asmlinkage int vprintk(const char *fmt, va_list args)
        for ( ; *p; p++) {
                if (new_text_line) {
                        /* Always output the token */
-                       emit_log_char('<');
-                       emit_log_char(current_log_level + '0');
-                       emit_log_char('>');
+                       emit_log_char(syslog_ns, '<');
+                       emit_log_char(syslog_ns, current_log_level + '0');
+                       emit_log_char(syslog_ns, '>');
                        printed_len += 3;
                        new_text_line = 0;
 
@@ -755,12 +729,13 @@ asmlinkage int vprintk(const char *fmt, va_list args)
 
                                t = cpu_clock(printk_cpu);
                                nanosec_rem = do_div(t, 1000000000);
-                               tlen = sprintf(tbuf, "[%5lu.%06lu] ",
+                               tlen = sprintf(tbuf, "ns_id='%d' %5lu.%06lu] ",
+                                               syslog_ns->handle,
                                                (unsigned long) t,
                                                nanosec_rem / 1000);
 
                                for (tp = tbuf; tp < tbuf + tlen; tp++)
-                                       emit_log_char(*tp);
+                                       emit_log_char(syslog_ns, *tp);
                                printed_len += tlen;
                        }
 
@@ -768,7 +743,7 @@ asmlinkage int vprintk(const char *fmt, va_list args)
                                break;
                }
 
-               emit_log_char(*p);
+               emit_log_char(syslog_ns, *p);
                if (*p == '\n')
                        new_text_line = 1;
        }
@@ -783,7 +758,7 @@ asmlinkage int vprintk(const char *fmt, va_list args)
         * will release 'logbuf_lock' regardless of whether it
         * actually gets the semaphore or not.
         */
-       if (acquire_console_semaphore_for_printk(this_cpu))
+       if (acquire_console_semaphore_for_printk(syslog_ns, this_cpu))
                release_console_sem();
 
        lockdep_on();
@@ -796,12 +771,6 @@ out_restore_irqs:
 EXPORT_SYMBOL(printk);
 EXPORT_SYMBOL(vprintk);
 
-#else
-
-static void call_console_drivers(unsigned start, unsigned end)
-{
-}
-
 #endif
 
 static int __add_preferred_console(char *name, int idx, char *options,
@@ -1034,36 +1003,40 @@ void wake_up_klogd(void)
  */
 void release_console_sem(void)
 {
-       unsigned long flags;
-       unsigned _con_start, _log_end;
-       unsigned wake_klogd = 0;
-
        if (console_suspended) {
                up(&console_sem);
                return;
        }
 
        console_may_schedule = 0;
-
-       for ( ; ; ) {
-               spin_lock_irqsave(&logbuf_lock, flags);
-               wake_klogd |= log_start - log_end;
-               if (con_start == log_end)
-                       break;                  /* Nothing to print */
-               _con_start = con_start;
-               _log_end = log_end;
-               con_start = log_end;            /* Flush */
-               spin_unlock(&logbuf_lock);
-               stop_critical_timings();        /* don't trace print latency */
-               call_console_drivers(_con_start, _log_end);
-               start_critical_timings();
-               local_irq_restore(flags);
+#ifdef CONFIG_PRINTK
+       {
+               unsigned long flags;
+               unsigned _con_start, _log_end;
+               unsigned wake_klogd = 0;
+               struct syslog_ns *syslog_ns = current_syslog_ns();
+
+               for ( ; ; ) {
+                       spin_lock_irqsave(&sys_log_lock, flags);
+                       wake_klogd |= sys_log_start - sys_log_end;
+                       if (sys_log_con_start == sys_log_end)
+                               break;                  /* Nothing to print */
+                       _con_start = sys_log_con_start;
+                       _log_end = sys_log_end;
+                       sys_log_con_start = sys_log_end;        /* Flush */
+                       spin_unlock(&sys_log_lock);
+                       stop_critical_timings();/* don't trace print latency */
+                       call_console_drivers(syslog_ns, _con_start, _log_end);
+                       start_critical_timings();
+                       local_irq_restore(flags);
+               }
+               spin_unlock_irqrestore(&sys_log_lock, flags);
+               if (wake_klogd)
+                       wake_up_klogd();
        }
+#endif
        console_locked = 0;
        up(&console_sem);
-       spin_unlock_irqrestore(&logbuf_lock, flags);
-       if (wake_klogd)
-               wake_up_klogd();
 }
 EXPORT_SYMBOL(release_console_sem);
 
@@ -1168,7 +1141,6 @@ EXPORT_SYMBOL(console_start);
 void register_console(struct console *newcon)
 {
        int i;
-       unsigned long flags;
        struct console *bcon = NULL;
 
        /*
@@ -1274,15 +1246,21 @@ void register_console(struct console *newcon)
                newcon->next = console_drivers->next;
                console_drivers->next = newcon;
        }
+#ifdef CONFIG_PRINTK
        if (newcon->flags & CON_PRINTBUFFER) {
+               unsigned long flags;
                /*
                 * release_console_sem() will print out the buffered messages
                 * for us.
                 */
-               spin_lock_irqsave(&logbuf_lock, flags);
-               con_start = log_start;
-               spin_unlock_irqrestore(&logbuf_lock, flags);
+
+               struct syslog_ns *syslog_ns = current_syslog_ns();
+
+               spin_lock_irqsave(&sys_log_lock, flags);
+               sys_log_con_start = sys_log_start;
+               spin_unlock_irqrestore(&sys_log_lock, flags);
        }
+#endif
        release_console_sem();
 
        /*
@@ -1486,27 +1464,28 @@ void kmsg_dump(enum kmsg_dump_reason reason)
        const char *s1, *s2;
        unsigned long l1, l2;
        unsigned long flags;
+       struct syslog_ns *syslog_ns = current_syslog_ns();
 
        /* 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. */
-       spin_lock_irqsave(&logbuf_lock, flags);
-       end = log_end & LOG_BUF_MASK;
-       chars = logged_chars;
-       spin_unlock_irqrestore(&logbuf_lock, flags);
+       spin_lock_irqsave(&sys_log_lock, flags);
+       end = sys_log_end & LOG_BUF_MASK(syslog_ns);
+       chars = sys_log_logged_chars;
+       spin_unlock_irqrestore(&sys_log_lock, flags);
 
-       if (logged_chars > end) {
-               s1 = log_buf + log_buf_len - logged_chars + end;
-               l1 = logged_chars - end;
+       if (sys_log_logged_chars > end) {
+               s1 = sys_log_buf + sys_log_buf_len - sys_log_logged_chars + end;
+               l1 = sys_log_logged_chars - end;
 
-               s2 = log_buf;
+               s2 = sys_log_buf;
                l2 = end;
        } else {
                s1 = "";
                l1 = 0;
 
-               s2 = log_buf + end - logged_chars;
-               l2 = logged_chars;
+               s2 = sys_log_buf + end - sys_log_logged_chars;
+               l2 = sys_log_logged_chars;
        }
 
        if (!spin_trylock_irqsave(&dump_list_lock, flags)) {
@@ -1519,3 +1498,4 @@ void kmsg_dump(enum kmsg_dump_reason reason)
        spin_unlock_irqrestore(&dump_list_lock, flags);
 }
 #endif
+