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 db2aebc34170d5364fc0a5fd72cdeea2f22a2c3c..c5ca63253b45575cca7e9e2c1f69b8c5a2b16e8d 100644 (file)
--- 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 c6edce3167b4116673cb8ddf937f7507b2dc5f02..d0c2dd1aa7e4c7038e8c7d7f55b6593c570b6176 100644 (file)
--- 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 9baf660ded332a2570b32a34114bf322d4453e5e..4179fb7c6720e7107f78d2d492f393d8fbc00227 100644 (file)
--- 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 0efc23c5c61b749c996783f604c26a537d822416..e1ed2a3108d591a795f371affecbc1c7421294cb 100644 (file)
--- 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,
+};