From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Tue, 24 May 2011 16:20:48 +0000 (-0400)
Subject: Add tracepoint listing ABI
X-Git-Tag: v2.0-pre1~96
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=271b66812595fb4be4ce1cb2b8277d97b13d795e;p=lttng-modules.git

Add tracepoint listing ABI

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---

diff --git a/ltt-debugfs-abi.c b/ltt-debugfs-abi.c
index db2aebc3..c5ca6325 100644
--- a/ltt-debugfs-abi.c
+++ b/ltt-debugfs-abi.c
@@ -84,6 +84,33 @@ fd_error:
 	return ret;
 }
 
+static
+int lttng_abi_tracepoint_list(void)
+{
+	struct file *tracepoint_list_file;
+	int file_fd, ret;
+
+	file_fd = get_unused_fd();
+	if (file_fd < 0) {
+		ret = file_fd;
+		goto fd_error;
+	}
+	tracepoint_list_file = anon_inode_getfile("[lttng_session]",
+					  &lttng_tracepoint_list_fops,
+					  NULL, O_RDWR);
+	if (IS_ERR(tracepoint_list_file)) {
+		ret = PTR_ERR(tracepoint_list_file);
+		goto file_error;
+	}
+	fd_install(file_fd, tracepoint_list_file);
+	return file_fd;
+
+file_error:
+	put_unused_fd(file_fd);
+fd_error:
+	return ret;
+}
+
 static
 long lttng_abi_tracer_version(struct file *file, 
 	struct lttng_kernel_tracer_version __user *uversion_param)
@@ -109,6 +136,10 @@ long lttng_abi_tracer_version(struct file *file,
  *	This ioctl implements lttng commands:
  *	LTTNG_KERNEL_SESSION
  *		Returns a LTTng trace session file descriptor
+ *	LTTNG_KERNEL_TRACER_VERSION
+ *		Returns the LTTng kernel tracer version
+ *	LTTNG_KERNEL_TRACEPOINT_LIST
+ *		Returns a file descriptor listing available tracepoints
  *
  * The returned session will be deleted when its file descriptor is closed.
  */
@@ -121,6 +152,8 @@ long lttng_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 	case LTTNG_KERNEL_TRACER_VERSION:
 		return lttng_abi_tracer_version(file,
 				(struct lttng_kernel_tracer_version __user *) arg);
+	case LTTNG_KERNEL_TRACEPOINT_LIST:
+		return lttng_abi_tracepoint_list();
 	default:
 		return -ENOIOCTLCMD;
 	}
@@ -155,8 +188,8 @@ void lttng_metadata_create_events(struct file *channel_file)
 	 */
 	event = ltt_event_create(channel, &metadata_params, NULL);
 	if (!event) {
-		goto create_error;
 		ret = -EINVAL;
+		goto create_error;
 	}
 	return;
 
@@ -389,7 +422,7 @@ int lttng_abi_create_event(struct file *channel_file,
 	 */
 	event = ltt_event_create(channel, &event_param, NULL);
 	if (!event) {
-		ret = -EEXIST;
+		ret = -EINVAL;
 		goto event_error;
 	}
 	event_file->private_data = event;
diff --git a/ltt-debugfs-abi.h b/ltt-debugfs-abi.h
index c6edce31..d0c2dd1a 100644
--- a/ltt-debugfs-abi.h
+++ b/ltt-debugfs-abi.h
@@ -69,6 +69,7 @@ struct lttng_kernel_tracer_version {
 #define LTTNG_KERNEL_SESSION			_IO(0xF6, 0x40)
 #define LTTNG_KERNEL_TRACER_VERSION		\
 	_IOR(0xF6, 0x41, struct lttng_kernel_tracer_version)
+#define LTTNG_KERNEL_TRACEPOINT_LIST		_IO(0xF6, 0x42)
 
 /* Session FD ioctl */
 #define LTTNG_KERNEL_METADATA			\
diff --git a/ltt-events.h b/ltt-events.h
index 9baf660d..4179fb7c 100644
--- a/ltt-events.h
+++ b/ltt-events.h
@@ -305,4 +305,7 @@ void lttng_ftrace_unregister(struct ltt_event *event)
 {
 }
 #endif
+
+extern const struct file_operations lttng_tracepoint_list_fops;
+
 #endif /* _LTT_EVENTS_H */
diff --git a/ltt-probes.c b/ltt-probes.c
index 0efc23c5..e1ed2a31 100644
--- a/ltt-probes.c
+++ b/ltt-probes.c
@@ -9,6 +9,7 @@
 #include <linux/module.h>
 #include <linux/list.h>
 #include <linux/mutex.h>
+#include <linux/seq_file.h>
 
 #include "ltt-events.h"
 
@@ -82,3 +83,72 @@ void ltt_event_put(const struct lttng_event_desc *event)
 	module_put(event->owner);
 }
 EXPORT_SYMBOL_GPL(ltt_event_put);
+
+static
+void *tp_list_start(struct seq_file *m, loff_t *pos)
+{
+	struct lttng_probe_desc *probe_desc;
+	int iter = 0, i;
+
+	list_for_each_entry(probe_desc, &probe_list, head) {
+		for (i = 0; i < probe_desc->nr_events; i++) {
+			if (iter++ >= *pos)
+				return (void *) &probe_desc->event_desc[i];
+		}
+	}
+	/* End of list */
+	return NULL;
+}
+
+static
+void *tp_list_next(struct seq_file *m, void *p, loff_t *ppos)
+{
+	struct lttng_probe_desc *probe_desc;
+	int iter = 0, i;
+
+	(*ppos)++;
+	list_for_each_entry(probe_desc, &probe_list, head) {
+		for (i = 0; i < probe_desc->nr_events; i++) {
+			if (iter++ >= *ppos)
+				return (void *) &probe_desc->event_desc[i];
+		}
+	}
+	/* End of list */
+	return NULL;
+}
+
+static
+void tp_list_stop(struct seq_file *m, void *p)
+{
+}
+
+static
+int tp_list_show(struct seq_file *m, void *p)
+{
+	const struct lttng_event_desc *probe_desc = p;
+
+	seq_printf(m,	"event { name = %s; };\n",
+		   probe_desc->name);
+	return 0;
+}
+
+static
+const struct seq_operations lttng_tracepoint_list_seq_ops = {
+	.start = tp_list_start,
+	.next = tp_list_next,
+	.stop = tp_list_stop,
+	.show = tp_list_show,
+};
+
+static
+int lttng_tracepoint_list_open(struct inode *inode, struct file *file)
+{
+	return seq_open(file, &lttng_tracepoint_list_seq_ops);
+}
+
+const struct file_operations lttng_tracepoint_list_fops = {
+	.open = lttng_tracepoint_list_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = seq_release_private,
+};