Add a new /dev/lttng-logger interface

This is identical to /proc/lttng-logger but has the advantage of working
from within containers when the path is made accessible to them.

Fixes: #1145
Signed-off-by: Stéphane Graber <stgraber@ubuntu.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

diff --git a/probes/lttng.c b/probes/lttng.c
index 09045fac18529702ad2ceac0ce7319c8cf2f549b..449d8a5cb7f4f5192604d1689ae73935e3bc1e97 100644 (file)
--- a/probes/lttng.c
+++ b/probes/lttng.c
@@ -28,6 +28,7 @@
 #include <linux/proc_fs.h>
 #include <linux/slab.h>
 #include <linux/mm.h>
+#include <linux/miscdevice.h>
 #include <wrapper/vmalloc.h>
 #include <lttng-events.h>
 
@@ -105,19 +106,37 @@ static const struct file_operations lttng_logger_operations = {
        .write = lttng_logger_write,
 };
 
+static struct miscdevice logger_dev = {
+       .minor = MISC_DYNAMIC_MINOR,
+       .name = "lttng-logger",
+       .mode = 0666,
+       .fops = &lttng_logger_operations
+};
+
 int __init lttng_logger_init(void)
 {
        int ret = 0;
 
        wrapper_vmalloc_sync_all();
+
+       /* /dev/lttng-logger */
+       ret = misc_register(&logger_dev);
+       if (ret) {
+               printk(KERN_ERR "Error creating LTTng logger device\n");
+               goto error;
+       }
+
+       /* /proc/lttng-logger */
        lttng_logger_dentry = proc_create_data(LTTNG_LOGGER_FILE,
                                S_IRUGO | S_IWUGO, NULL,
                                &lttng_logger_operations, NULL);
        if (!lttng_logger_dentry) {
-               printk(KERN_ERR "Error creating LTTng logger file\n");
+               printk(KERN_ERR "Error creating LTTng logger proc file\n");
                ret = -ENOMEM;
-               goto error;
+               goto error_proc;
        }
+
+       /* Init */
        ret = __lttng_events_init__lttng();
        if (ret)
                goto error_events;
@@ -125,6 +144,8 @@ int __init lttng_logger_init(void)
 
 error_events:
        remove_proc_entry("lttng-logger", NULL);
+error_proc:
+       misc_deregister(&logger_dev);
 error:
        return ret;
 }
@@ -134,4 +155,5 @@ void lttng_logger_exit(void)
        __lttng_events_exit__lttng();
        if (lttng_logger_dentry)
                remove_proc_entry("lttng-logger", NULL);
+       misc_deregister(&logger_dev);
 }