trace: Provide a detailed event control interface

This interface decouples event obtaining from interaction.

Events can be obtained through three different methods:

* identifier
* name
* simple wildcard pattern

Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

1 files changed, 93 insertions, 13 deletions

diff --git a/trace/control.c b/trace/control.c
index be05efb99b..49f61e137b 100644
--- a/trace/control.c
+++ b/trace/control.c
@@ -1,19 +1,86 @@
 /*
  * Interface for configuring and controlling the state of tracing events.
  *
- * Copyright (C) 2011 Lluís Vilanova <vilanova@ac.upc.edu>
+ * Copyright (C) 2011-2012 Lluís Vilanova <vilanova@ac.upc.edu>
  *
- * This work is licensed under the terms of the GNU GPL, version 2.  See
- * the COPYING file in the top-level directory.
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
  */
 
 #include "trace/control.h"
 
 
-void trace_backend_init_events(const char *fname)
+TraceEvent *trace_event_name(const char *name)
+{
+    assert(name != NULL);
+
+    TraceEventID i;
+    for (i = 0; i < trace_event_count(); i++) {
+        TraceEvent *ev = trace_event_id(i);
+        if (strcmp(trace_event_get_name(ev), name) == 0) {
+            return ev;
+        }
+    }
+    return NULL;
+}
+
+static bool pattern_glob(const char *pat, const char *ev)
+{
+    while (*pat != '\0' && *ev != '\0') {
+        if (*pat == *ev) {
+            pat++;
+            ev++;
+        }
+        else if (*pat == '*') {
+            if (pattern_glob(pat, ev+1)) {
+                return true;
+            } else if (pattern_glob(pat+1, ev)) {
+                return true;
+            } else {
+                return false;
+            }
+        } else {
+            return false;
+        }
+    }
+
+    while (*pat == '*') {
+        pat++;
+    }
+
+    if (*pat == '\0' && *ev == '\0') {
+        return true;
+    } else {
+        return false;
+    }
+}
+
+TraceEvent *trace_event_pattern(const char *pat, TraceEvent *ev)
 {
-    int ret;
+    assert(pat != NULL);
 
+    TraceEventID i;
+
+    if (ev == NULL) {
+        i = -1;
+    } else {
+        i = trace_event_get_id(ev);
+    }
+    i++;
+
+    while (i < trace_event_count()) {
+        TraceEvent *res = trace_event_id(i);
+        if (pattern_glob(pat, trace_event_get_name(res))) {
+            return res;
+        }
+        i++;
+    }
+
+    return NULL;
+}
+
+void trace_backend_init_events(const char *fname)
+{
     if (fname == NULL) {
         return;
     }
@@ -32,15 +99,28 @@ void trace_backend_init_events(const char *fname)
             if ('#' == line_buf[0]) { /* skip commented lines */
                 continue;
             }
-            if ('-' == line_buf[0]) {
-                ret = trace_event_set_state(line_buf+1, false);
+            const bool enable = ('-' != line_buf[0]);
+            char *line_ptr = enable ? line_buf : line_buf + 1;
+            if (trace_event_is_pattern(line_ptr)) {
+                TraceEvent *ev = NULL;
+                while ((ev = trace_event_pattern(line_ptr, ev)) != NULL) {
+                    if (trace_event_get_state_static(ev)) {
+                        trace_event_set_state_dynamic(ev, enable);
+                    }
+                }
             } else {
-                ret = trace_event_set_state(line_buf, true);
-            }
-            if (!ret) {
-                fprintf(stderr,
-                        "error: trace event '%s' does not exist\n", line_buf);
-                exit(1);
+                TraceEvent *ev = trace_event_name(line_ptr);
+                if (ev == NULL) {
+                    fprintf(stderr,
+                            "error: trace event '%s' does not exist\n", line_ptr);
+                    exit(1);
+                }
+                if (!trace_event_get_state_static(ev)) {
+                    fprintf(stderr,
+                            "error: trace event '%s' is not traceable\n", line_ptr);
+                    exit(1);
+                }
+                trace_event_set_state_dynamic(ev, enable);
             }
         }
     }