[lttng-dev] [PATCH lttng-modules] Add a new /dev/lttng-logger interface

[Mathieu Desnoyers]

Merged into master branch of lttng-modules, thanks!

Mathieu

----- On Dec 19, 2017, at 3:55 PM, Stéphane Graber stgraber at ubuntu.com wrote:

> 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 at ubuntu.com>
> ---
> probes/lttng.c | 26 ++++++++++++++++++++++++--
> 1 file changed, 24 insertions(+), 2 deletions(-)
> 
> diff --git a/probes/lttng.c b/probes/lttng.c
> index 09045fa..449d8a5 100644
> --- 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);
> }
> --
> 2.14.1

-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com