Command to dump the metadata cache again

[deliverable/lttng-modules.git] / lttng-abi.c

diff --git a/lttng-abi.c b/lttng-abi.c
index 54988b79d0821da9ef71d02f845c2345b1ea730f..d202b728451209526e02bc8dae0a984570521bc5 100644 (file)
--- a/lttng-abi.c
+++ b/lttng-abi.c
@@ -44,18 +44,19 @@
 #include <linux/uaccess.h>
 #include <linux/slab.h>
 #include <linux/err.h>
-#include "wrapper/vmalloc.h"   /* for wrapper_vmalloc_sync_all() */
-#include "wrapper/ringbuffer/vfs.h"
-#include "wrapper/ringbuffer/backend.h"
-#include "wrapper/ringbuffer/frontend.h"
-#include "wrapper/poll.h"
-#include "wrapper/file.h"
-#include "wrapper/kref.h"
-#include "lttng-abi.h"
-#include "lttng-abi-old.h"
-#include "lttng-events.h"
-#include "lttng-tracer.h"
-#include "lib/ringbuffer/frontend_types.h"
+#include <wrapper/vmalloc.h>   /* for wrapper_vmalloc_sync_all() */
+#include <wrapper/ringbuffer/vfs.h>
+#include <wrapper/ringbuffer/backend.h>
+#include <wrapper/ringbuffer/frontend.h>
+#include <wrapper/poll.h>
+#include <wrapper/file.h>
+#include <wrapper/kref.h>
+#include <lttng-string-utils.h>
+#include <lttng-abi.h>
+#include <lttng-abi-old.h>
+#include <lttng-events.h>
+#include <lttng-tracer.h>
+#include <lib/ringbuffer/frontend_types.h>
 
 /*
  * This is LTTng's own personal way to create a system call as an external
@@ -396,7 +397,7 @@ int lttng_abi_create_channel(struct file *session_file,
                fops = &lttng_metadata_fops;
                break;
        }
-               
+
        chan_file = anon_inode_getfile("[lttng_channel]",
                                       fops,
                                       NULL, O_RDWR);
@@ -569,6 +570,8 @@ long lttng_session_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
                return lttng_session_list_tracker_pids(session);
        case LTTNG_KERNEL_SESSION_METADATA_REGEN:
                return lttng_session_metadata_regenerate(session);
+       case LTTNG_KERNEL_SESSION_STATEDUMP:
+               return lttng_session_statedump(session);
        default:
                return -ENOIOCTLCMD;
        }
@@ -651,6 +654,38 @@ void lttng_metadata_ring_buffer_ioctl_put_next_subbuf(struct file *filp,
        stream->metadata_out = stream->metadata_in;
 }
 
+/*
+ * Reset the counter of how much metadata has been consumed to 0. That way,
+ * the consumer receives the content of the metadata cache unchanged. This is
+ * different from the metadata_regenerate where the offset from epoch is
+ * resampled, here we want the exact same content as the last time the metadata
+ * was generated. This command is only possible if all the metadata written
+ * in the cache has been output to the metadata stream to avoid corrupting the
+ * metadata file.
+ *
+ * Return 0 on success, a negative value on error.
+ */
+static
+int lttng_metadata_cache_dump(struct lttng_metadata_stream *stream)
+{
+       int ret;
+       struct lttng_metadata_cache *cache = stream->metadata_cache;
+
+       mutex_lock(&cache->lock);
+       if (stream->metadata_out != cache->metadata_written) {
+               ret = -EBUSY;
+               goto end;
+       }
+       stream->metadata_out = 0;
+       stream->metadata_in = 0;
+       wake_up_interruptible(&stream->read_wait);
+       ret = 0;
+
+end:
+       mutex_unlock(&cache->lock);
+       return ret;
+}
+
 static
 long lttng_metadata_ring_buffer_ioctl(struct file *filp,
                unsigned int cmd, unsigned long arg)
@@ -681,6 +716,7 @@ long lttng_metadata_ring_buffer_ioctl(struct file *filp,
                 */
                return -ENOSYS;
        }
+       case RING_BUFFER_FLUSH_EMPTY:   /* Fall-through. */
        case RING_BUFFER_FLUSH:
        {
                struct lttng_metadata_stream *stream = filp->private_data;
@@ -702,6 +738,12 @@ long lttng_metadata_ring_buffer_ioctl(struct file *filp,
 
                return put_u64(stream->version, arg);
        }
+       case RING_BUFFER_METADATA_CACHE_DUMP:
+       {
+               struct lttng_metadata_stream *stream = filp->private_data;
+
+               return lttng_metadata_cache_dump(stream);
+       }
        default:
                break;
        }
@@ -757,6 +799,34 @@ long lttng_metadata_ring_buffer_compat_ioctl(struct file *filp,
                 */
                return -ENOSYS;
        }
+       case RING_BUFFER_FLUSH_EMPTY:   /* Fall-through. */
+       case RING_BUFFER_FLUSH:
+       {
+               struct lttng_metadata_stream *stream = filp->private_data;
+               struct lib_ring_buffer *buf = stream->priv;
+               struct channel *chan = buf->backend.chan;
+
+               /*
+                * Before doing the actual ring buffer flush, write up to one
+                * packet of metadata in the ring buffer.
+                */
+               ret = lttng_metadata_output_channel(stream, chan);
+               if (ret < 0)
+                       goto err;
+               break;
+       }
+       case RING_BUFFER_GET_METADATA_VERSION:
+       {
+               struct lttng_metadata_stream *stream = filp->private_data;
+
+               return put_u64(stream->version, arg);
+       }
+       case RING_BUFFER_METADATA_CACHE_DUMP:
+       {
+               struct lttng_metadata_stream *stream = filp->private_data;
+
+               return lttng_metadata_cache_dump(stream);
+       }
        default:
                break;
        }
@@ -774,12 +844,6 @@ long lttng_metadata_ring_buffer_compat_ioctl(struct file *filp,
                                cmd, arg);
                break;
        }
-       case RING_BUFFER_GET_METADATA_VERSION:
-       {
-               struct lttng_metadata_stream *stream = filp->private_data;
-
-               return put_u64(stream->version, arg);
-       }
        default:
                break;
        }
@@ -957,8 +1021,11 @@ int lttng_abi_open_metadata_stream(struct file *channel_file)
                goto notransport;
        }
 
-       if (!lttng_kref_get(&session->metadata_cache->refcount))
+       if (!lttng_kref_get(&session->metadata_cache->refcount)) {
+               ret = -EOVERFLOW;
                goto kref_error;
+       }
+
        ret = lttng_abi_create_stream_fd(channel_file, stream_priv,
                        &lttng_metadata_ring_buffer_file_operations);
        if (ret < 0)
@@ -1017,14 +1084,19 @@ int lttng_abi_create_event(struct file *channel_file,
        /* The event holds a reference on the channel */
        if (atomic_long_add_unless(&channel_file->f_count,
                1, INT_MAX) == INT_MAX) {
+               ret = -EOVERFLOW;
                goto refcount_error;
        }
        if (event_param->instrumentation == LTTNG_KERNEL_TRACEPOINT
                        || event_param->instrumentation == LTTNG_KERNEL_SYSCALL) {
                struct lttng_enabler *enabler;
 
-               if (event_param->name[strlen(event_param->name) - 1] == '*') {
-                       enabler = lttng_enabler_create(LTTNG_ENABLER_WILDCARD,
+               if (strutils_is_star_glob_pattern(event_param->name)) {
+                       /*
+                        * If the event name is a star globbing pattern,
+                        * we create the special star globbing enabler.
+                        */
+                       enabler = lttng_enabler_create(LTTNG_ENABLER_STAR_GLOB,
                                event_param, channel);
                } else {
                        enabler = lttng_enabler_create(LTTNG_ENABLER_NAME,
@@ -1701,7 +1773,7 @@ int __init lttng_abi_init(void)
        lttng_clock_ref();
        lttng_proc_dentry = proc_create_data("lttng", S_IRUSR | S_IWUSR, NULL,
                                        &lttng_fops, NULL);
-       
+
        if (!lttng_proc_dentry) {
                printk(KERN_ERR "Error creating LTTng control file\n");
                ret = -ENOMEM;