[lttng-dev] [PATCH lttng-modules 1/3] Introduce LTTNG_KERNEL_SESSION_SET_NAME

[Mathieu Desnoyers]

All 3 patches merged into modules 2.11 and master, thanks!

Mathieu

----- On Aug 13, 2019, at 2:14 PM, Jonathan Rajotte jonathan.rajotte-julien at efficios.com wrote:

> The tracer controller (lttng-sessiond) can now inform the kernel tracer
> of the name of the created session. This will allow the tracer to
> propagate the information inside the trace metadata under a "env" field.
> 
> This information is normally inferred from the generated folder
> structure where a trace rests.
> 
> Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers at efficios.com>
> Signed-off-by: Jonathan Rajotte <jonathan.rajotte-julien at efficios.com>
> ---
> 
> This should also be backported to 2.11 allowing Babeltrace 2 to merge
> traces from archived data (rotation) and output a trace with similar
> lttng tree hierarchy.
> 
> ---
> lttng-abi.c    | 27 +++++++++++++++++++++++++++
> lttng-abi.h    | 10 +++++++++-
> lttng-events.h |  1 +
> 3 files changed, 37 insertions(+), 1 deletion(-)
> 
> diff --git a/lttng-abi.c b/lttng-abi.c
> index ca94379..aab2cac 100644
> --- a/lttng-abi.c
> +++ b/lttng-abi.c
> @@ -453,6 +453,23 @@ fd_error:
> 	return ret;
> }
> 
> +static
> +int lttng_abi_session_set_name(struct lttng_session *session,
> +		struct lttng_kernel_session_name *name)
> +{
> +	size_t len;
> +
> +	len = strnlen(name->name, LTTNG_KERNEL_SESSION_NAME_LEN);
> +
> +	if (len == LTTNG_KERNEL_SESSION_NAME_LEN) {
> +		/* Name is too long/malformed */
> +		return -EINVAL;
> +	}
> +
> +	strcpy(session->name, name->name);
> +	return 0;
> +}
> +
> /**
>  *	lttng_session_ioctl - lttng session fd ioctl
>  *
> @@ -562,6 +579,16 @@ long lttng_session_ioctl(struct file *file, unsigned int
> cmd, unsigned long arg)
> 		return lttng_session_metadata_regenerate(session);
> 	case LTTNG_KERNEL_SESSION_STATEDUMP:
> 		return lttng_session_statedump(session);
> +	case LTTNG_KERNEL_SESSION_SET_NAME:
> +	{
> +		struct lttng_kernel_session_name name;
> +
> +		if (copy_from_user(&name,
> +				(struct lttng_kernel_session_name __user *) arg,
> +				sizeof(struct lttng_kernel_session_name)))
> +			return -EFAULT;
> +		return lttng_abi_session_set_name(session, &name);
> +	}
> 	default:
> 		return -ENOIOCTLCMD;
> 	}
> diff --git a/lttng-abi.h b/lttng-abi.h
> index 83bf931..0dd9a9f 100644
> --- a/lttng-abi.h
> +++ b/lttng-abi.h
> @@ -17,9 +17,10 @@
>  * should be increased when an incompatible ABI change is done.
>  */
> #define LTTNG_MODULES_ABI_MAJOR_VERSION		2
> -#define LTTNG_MODULES_ABI_MINOR_VERSION		3
> +#define LTTNG_MODULES_ABI_MINOR_VERSION		4
> 
> #define LTTNG_KERNEL_SYM_NAME_LEN	256
> +#define LTTNG_KERNEL_SESSION_NAME_LEN	256
> 
> enum lttng_kernel_instrumentation {
> 	LTTNG_KERNEL_TRACEPOINT	= 0,
> @@ -119,6 +120,10 @@ struct lttng_kernel_tracer_abi_version {
> 	uint32_t minor;
> } __attribute__((packed));
> 
> +struct lttng_kernel_session_name {
> +	char name[LTTNG_KERNEL_SESSION_NAME_LEN];
> +} __attribute__((packed));
> +
> enum lttng_kernel_calibrate_type {
> 	LTTNG_KERNEL_CALIBRATE_KRETPROBE,
> };
> @@ -209,8 +214,11 @@ struct lttng_kernel_filter_bytecode {
>  */
> #define LTTNG_KERNEL_SESSION_LIST_TRACKER_PIDS	_IO(0xF6, 0x58)
> #define LTTNG_KERNEL_SESSION_METADATA_REGEN	_IO(0xF6, 0x59)
> +
> /* 0x5A and 0x5B are reserved for a future ABI-breaking cleanup. */
> #define LTTNG_KERNEL_SESSION_STATEDUMP		_IO(0xF6, 0x5C)
> +#define LTTNG_KERNEL_SESSION_SET_NAME		\
> +	_IOR(0xF6, 0x5D, struct lttng_kernel_session_name)
> 
> /* Channel FD ioctl */
> #define LTTNG_KERNEL_STREAM			_IO(0xF6, 0x62)
> diff --git a/lttng-events.h b/lttng-events.h
> index 1903706..bdd73ff 100644
> --- a/lttng-events.h
> +++ b/lttng-events.h
> @@ -521,6 +521,7 @@ struct lttng_session {
> 	struct list_head enablers_head;
> 	/* Hash table of events */
> 	struct lttng_event_ht events_ht;
> +	char name[LTTNG_KERNEL_SESSION_NAME_LEN];
> };
> 
> struct lttng_metadata_cache {
> --
> 2.17.1

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