[lttng-dev] [PATCH] lttng-tools lttng-ctl, calibrate and create : Document return values
Thibault, Daniel
Daniel.Thibault at drdc-rddc.gc.ca
Mon Jan 30 15:58:08 EST 2012
This third patch documents (and in one instance, enforces) return values for functions of lttng-ctl, calibrate and create.
It also fixes the test of getgroups(), which cannot return (grp_id < -1).
------------------------------
>From 6739ca025c89937cd4e37c933715532fdc39ced0 Mon, 30 Jan 2012 15:54:01 -0500
From: Daniel U. Thibault <daniel.thibault at drdc-rddc.gc.ca>
Date: Mon, 30 Jan 2012 15:53:49 -0500
Subject: [PATCH] lttng-tools lttng-ctl, calibrate and create : Document return values
Signed-off-by: Daniel U. Thibault <daniel.thibault at drdc-rddc.gc.ca>
diff --git a/lttng2-lttng-tools-2.0-pre18+-5c73c59/src/bin/lttng/commands/calibrate.c b/lttng2-lttng-tools-2.0-pre18+-5c73c59/src/bin/lttng/commands/calibrate.c
index a3c7b52..a60cadf 100644
--- a/lttng2-lttng-tools-2.0-pre18+-5c73c59/src/bin/lttng/commands/calibrate.c
+++ b/lttng2-lttng-tools-2.0-pre18+-5c73c59/src/bin/lttng/commands/calibrate.c
@@ -182,6 +182,8 @@
/*
* Calibrate LTTng tracer.
+ *
+ * Returns a CMD_* error.
*/
int cmd_calibrate(int argc, const char **argv)
{
diff --git a/lttng2-lttng-tools-2.0-pre18+-5c73c59/src/bin/lttng/commands/create.c b/lttng2-lttng-tools-2.0-pre18+-5c73c59/src/bin/lttng/commands/create.c
index 34754c7..9dc3752 100644
--- a/lttng2-lttng-tools-2.0-pre18+-5c73c59/src/bin/lttng/commands/create.c
+++ b/lttng2-lttng-tools-2.0-pre18+-5c73c59/src/bin/lttng/commands/create.c
@@ -52,17 +52,18 @@
{
fprintf(ofp, "usage: lttng create [options] [NAME]\n");
fprintf(ofp, "\n");
+ fprintf(ofp, " The default NAME is 'auto-yyyymmdd-hhmmss'\n");
fprintf(ofp, " -h, --help Show this help\n");
- fprintf(ofp, " --list-options Simple listing of options\n");
+ fprintf(ofp, " --list-options Simple listing of options\n");
fprintf(ofp, " -o, --output PATH Specify output path for traces\n");
fprintf(ofp, "\n");
}
/*
- * create_session
+ * Create a tracing session.
+ * If no name is specified, a default name is generated.
*
- * Create a tracing session. If no name specified, a default name will be
- * generated.
+ * Returns one of the CMD_* result constants.
*/
static int create_session()
{
@@ -147,9 +148,9 @@
}
/*
- * cmd_create
- *
* The 'create <options>' first level command
+ *
+ * Returns one of the CMD_* result constants.
*/
int cmd_create(int argc, const char **argv)
{
diff --git a/lttng2-lttng-tools-2.0-pre18+-5c73c59/src/lib/lttng-ctl/lttng-ctl.c b/lttng2-lttng-tools-2.0-pre18+-5c73c59/src/lib/lttng-ctl/lttng-ctl.c
index 6cc04ef..537934f 100644
--- a/lttng2-lttng-tools-2.0-pre18+-5c73c59/src/lib/lttng-ctl/lttng-ctl.c
+++ b/lttng2-lttng-tools-2.0-pre18+-5c73c59/src/lib/lttng-ctl/lttng-ctl.c
@@ -83,8 +83,8 @@
/*
* Send lttcomm_session_msg to the session daemon.
*
- * On success, return 0
- * On error, return error code
+ * On success, returns the number of bytes sent (>=0)
+ * On error, returns -1
*/
static int send_session_msg(struct lttcomm_session_msg *lsm)
{
@@ -105,8 +105,8 @@
/*
* Receive data from the sessiond socket.
*
- * On success, return 0
- * On error, return recv() error code
+ * On success, returns the number of bytes received (>=0)
+ * On error, returns -1 (recvmsg() error) or -ENOTCONN
*/
static int recv_data_sessiond(void *buf, size_t len)
{
@@ -124,7 +124,7 @@
}
/*
- * Check if the specified group name exist.
+ * Check if we are in the specified group.
*
* If yes return 1, else return -1.
*/
@@ -153,13 +153,14 @@
}
/* Alloc group list of the right size */
+ /* Note that malloc(0) will return a valid pointer */
grp_list = malloc(grp_list_size * sizeof(gid_t));
if (!grp_list) {
- ret = -1;
+ perror("malloc");
goto end;
}
grp_id = getgroups(grp_list_size, grp_list);
- if (grp_id < -1) {
+ if (grp_id < 0) {
perror("getgroups");
goto free_list;
}
@@ -209,8 +210,10 @@
}
/*
- * Set sessiond socket path by putting it in the global sessiond_sock_path
- * variable.
+ * Set sessiond socket path by putting it in the global
+ * sessiond_sock_path variable.
+ * Returns 0 on success,
+ * -ENOMEM on failure (the sessiond socket path is somehow too long)
*/
static int set_session_daemon_path(void)
{
@@ -268,7 +271,7 @@
ret = set_session_daemon_path();
if (ret < 0) {
- return ret;
+ return -1; /* set_session_daemon_path() returns -ENOMEM */
}
/* Connect to the sesssion daemon */
@@ -284,7 +287,8 @@
}
/*
- * Clean disconnect the session daemon.
+ * Clean disconnect from the session daemon.
+ * On success, return 0. On error, return -1.
*/
static int disconnect_sessiond(void)
{
@@ -373,6 +377,7 @@
/*
* Create lttng handle and return pointer.
+ * The returned pointer will be NULL in case of malloc() error.
*/
struct lttng_handle *lttng_create_handle(const char *session_name,
struct lttng_domain *domain)
@@ -408,6 +413,7 @@
/*
* Register an outside consumer.
+ * Returns size of returned session payload data or a negative error code.
*/
int lttng_register_consumer(struct lttng_handle *handle,
const char *socket_path)
@@ -425,7 +431,8 @@
}
/*
- * Start tracing for all trace of the session.
+ * Start tracing for all traces of the session.
+ * Returns size of returned session payload data or a negative error code.
*/
int lttng_start_tracing(const char *session_name)
{
@@ -443,7 +450,8 @@
}
/*
- * Stop tracing for all trace of the session.
+ * Stop tracing for all traces of the session.
+ * Returns size of returned session payload data or a negative error code.
*/
int lttng_stop_tracing(const char *session_name)
{
@@ -496,7 +504,10 @@
}
/*
- * Enable event
+ * Enable event(s) for a channel.
+ * If no event name is specified, all events are enabled.
+ * If no channel name is specified, the default 'channel0' is used.
+ * Returns size of returned session payload data or a negative error code.
*/
int lttng_enable_event(struct lttng_handle *handle,
struct lttng_event *ev, const char *channel_name)
@@ -532,7 +543,10 @@
}
/*
- * Disable event of a channel and domain.
+ * Disable event(s) of a channel and domain.
+ * If no event name is specified, all events are disabled.
+ * If no channel name is specified, the default 'channel0' is used.
+ * Returns size of returned session payload data or a negative error code.
*/
int lttng_disable_event(struct lttng_handle *handle, const char *name,
const char *channel_name)
@@ -567,7 +581,8 @@
}
/*
- * Enable channel per domain
+ * Enable channel per domain
+ * Returns size of returned session payload data or a negative error code.
*/
int lttng_enable_channel(struct lttng_handle *handle,
struct lttng_channel *chan)
@@ -594,7 +609,8 @@
}
/*
- * All tracing will be stopped for registered events of the channel.
+ * All tracing will be stopped for registered events of the channel.
+ * Returns size of returned session payload data or a negative error code.
*/
int lttng_disable_channel(struct lttng_handle *handle, const char *name)
{
@@ -619,10 +635,10 @@
}
/*
- * List all available tracepoints of domain.
- *
- * Return the size (bytes) of the list and set the events array.
- * On error, return negative value.
+ * Lists all available tracepoints of domain.
+ * Sets the contents of the events array.
+ * Returns the number of lttng_event entries in events;
+ * on error, returns a negative value.
*/
int lttng_list_tracepoints(struct lttng_handle *handle,
struct lttng_event **events)
@@ -646,10 +662,12 @@
}
/*
- * Return a human readable string of code
+ * Returns a human readable string describing
+ * the error code (a negative value).
*/
const char *lttng_strerror(int code)
{
+ /* lttcomm error codes range from -LTTCOMM_OK down to -LTTCOMM_NR */
if (code > -LTTCOMM_OK) {
return "Ended with errors";
}
@@ -658,7 +676,8 @@
}
/*
- * Create a brand new session using name.
+ * Create a brand new session using name and path.
+ * Returns size of returned session payload data or a negative error code.
*/
int lttng_create_session(const char *name, const char *path)
{
@@ -673,6 +692,7 @@
/*
* Destroy session using name.
+ * Returns size of returned session payload data or a negative error code.
*/
int lttng_destroy_session(const char *session_name)
{
@@ -691,9 +711,9 @@
/*
* Ask the session daemon for all available sessions.
- *
- * Return number of session.
- * On error, return negative value.
+ * Sets the contents of the sessions array.
+ * Returns the number of lttng_session entries in sessions;
+ * on error, returns a negative value.
*/
int lttng_list_sessions(struct lttng_session **sessions)
{
@@ -710,7 +730,10 @@
}
/*
- * List domain of a session.
+ * Ask the session daemon for all available domains of a session.
+ * Sets the contents of the domains array.
+ * Returns the number of lttng_domain entries in domains;
+ * on error, returns a negative value.
*/
int lttng_list_domains(const char *session_name,
struct lttng_domain **domains)
@@ -735,7 +758,10 @@
}
/*
- * List channels of a session
+ * Ask the session daemon for all available channels of a session.
+ * Sets the contents of the channels array.
+ * Returns the number of lttng_channel entries in channels;
+ * on error, returns a negative value.
*/
int lttng_list_channels(struct lttng_handle *handle,
struct lttng_channel **channels)
@@ -762,7 +788,10 @@
}
/*
- * List events of a session channel.
+ * Ask the session daemon for all available events of a session channel.
+ * Sets the contents of the events array.
+ * Returns the number of lttng_event entries in events;
+ * on error, returns a negative value.
*/
int lttng_list_events(struct lttng_handle *handle,
const char *channel_name, struct lttng_event **events)
@@ -792,8 +821,9 @@
}
/*
- * Set tracing group variable with name. This function allocate memory pointed
- * by tracing_group.
+ * Sets the tracing_group variable with name.
+ * This function allocates memory pointed to by tracing_group.
+ * On success, returns 0, on error, returns -1 (null name) or -ENOMEM.
*/
int lttng_set_tracing_group(const char *name)
{
@@ -831,6 +861,7 @@
/*
* Set default channel attributes.
+ * If either or both of the arguments are null, nothing happens.
*/
void lttng_channel_set_default_attr(struct lttng_domain *domain,
struct lttng_channel_attr *attr)
@@ -875,7 +906,7 @@
* Check if session daemon is alive.
*
* Return 1 if alive or 0 if not.
- * On error return -1
+ * On error returns a negative value.
*/
int lttng_session_daemon_alive(void)
{
------------------------------
Daniel U. Thibault
R & D pour la défense Canada - Valcartier (RDDC Valcartier) / Defence R&D Canada - Valcartier (DRDC Valcartier)
Système de systèmes (SdS) / System of Systems (SoS)
Solutions informatiques et expérimentations (SIE) / Computing Solutions and Experimentations (CSE)
2459 Boul. Pie XI Nord
Québec, QC G3J 1X5
CANADA
Vox : (418) 844-4000 x4245
Fax : (418) 844-4538
NAC: 918V QSDJ
Gouvernement du Canada / Government of Canada
<http://www.valcartier.drdc-rddc.gc.ca/>
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