Add trace listing feature

This patch adds the possibility to list the available traces for a
specific session.

The new lttng_trace data structure is a representation of a trace for
use for 'human output'.

Some fct are added to trace.c to get the trace count of a session and
list those traces. Also, trace counter are added to a ltt_session.

Some renaming is done to make things clearer. A name is added to a
userspace trace also.

Signed-off-by: David Goulet <david.goulet@polymtl.ca>

diff --git a/include/lttng/liblttngctl.h b/include/lttng/liblttngctl.h
index aeb822010230d0b3a2d612ce10230c911c2d185c..0ffa6f25896a45b003c6d382f1947e21bd92ffcd 100644 (file)
--- a/include/lttng/liblttngctl.h
+++ b/include/lttng/liblttngctl.h
@@ -35,6 +35,12 @@
  */
 #define UUID_STR_LEN 37
 
+/* Trace type for lttng_trace.
+ */
+enum lttng_trace_type {
+       KERNEL, USERSPACE,
+};
+
 /* Simple structure representing a session.
  */
 struct lttng_session {
@@ -42,6 +48,14 @@ struct lttng_session {
        char uuid[UUID_STR_LEN];
 };
 
+/* Simple trace representation.
+ */
+struct lttng_trace {
+       char name[NAME_MAX];
+       pid_t pid;
+       enum lttng_trace_type type;
+};
+
 extern int lttng_create_session(char *name, uuid_t *session_id);
 extern int lttng_destroy_session(uuid_t *uuid);
 extern int lttng_connect_sessiond(void);
@@ -51,6 +65,7 @@ extern int lttng_check_session_daemon(void);
 extern const char *lttng_get_readable_code(int code);
 extern int lttng_ust_list_apps(pid_t **pids);
 extern int lttng_list_sessions(struct lttng_session **sessions);
+extern int lttng_list_traces(uuid_t *uuid, struct lttng_trace **traces);
 extern void lttng_set_current_session_uuid(char *uuid);
 extern int lttng_ust_create_trace(pid_t pid);
 extern int lttng_ust_start_trace(pid_t pid);

diff --git a/liblttngctl/liblttngctl.c b/liblttngctl/liblttngctl.c
index 64764682ba18f6fe124900c4283cf74d8f58aaee..7d020daad2a9d83ca3a72d6dffd089b3e86189c3 100644 (file)
--- a/liblttngctl/liblttngctl.c
+++ b/liblttngctl/liblttngctl.c
@@ -218,6 +218,28 @@ int lttng_ust_list_apps(pid_t **pids)
        return ret / sizeof(pid_t);
 }
 
+/*
+ *  lttng_list_traces
+ *
+ *  Ask the session daemon for all traces (kernel and ust)
+ *  for the session identified by uuid.
+ *
+ *  Return the number of traces.
+ */
+int lttng_list_traces(uuid_t *uuid, struct lttng_trace **traces)
+{
+       int ret;
+
+       uuid_copy(lsm.session_id, *uuid);
+
+       ret = ask_sessiond(LTTNG_LIST_TRACES, (void **) traces);
+       if (ret < 0) {
+               return ret;
+       }
+
+       return ret / sizeof(struct lttng_trace);
+}
+
 /*
  *  lttng_create_session
  *

diff --git a/liblttsessiondcomm/liblttsessiondcomm.h b/liblttsessiondcomm/liblttsessiondcomm.h
index ce85e8292130e34dcb0c0a0fcc1dac016acc93e8..bd17a2ac6375003c06ee2a20c0d4b913a938bd28 100644 (file)
--- a/liblttsessiondcomm/liblttsessiondcomm.h
+++ b/liblttsessiondcomm/liblttsessiondcomm.h
@@ -45,6 +45,7 @@ enum lttcomm_command_type {
        LTTNG_GET_SUBBUF_NUM_SIZE,
        LTTNG_LIST_MARKERS,
        LTTNG_LIST_SESSIONS,
+       LTTNG_LIST_TRACES,
        LTTNG_LIST_TRACE_EVENTS,
        LTTNG_SETUP_TRACE,
        LTTNG_SET_SOCK_PATH,

diff --git a/ltt-sessiond/main.c b/ltt-sessiond/main.c
index 76834558ae32a58da62eabfef864ac90f6230287..70ce53c8b1cd50c87e1712bc42a2c2e0ba0f9bd4 100644 (file)
--- a/ltt-sessiond/main.c
+++ b/ltt-sessiond/main.c
@@ -309,6 +309,11 @@ static int ust_create_trace(pid_t pid)
        /* Init */
        trace->pid = pid;
        trace->shmid = 0;
+       /* NOTE: to be removed. Trace name will no longer be
+        * required for LTTng userspace tracer. For now, we set it
+        * to 'auto' for API compliance.
+        */
+       snprintf(trace->name, 5, "auto");
 
        /* Connect to app using ustctl API */
        sock = connect_app(pid);
@@ -317,7 +322,7 @@ static int ust_create_trace(pid_t pid)
                goto error;
        }
 
-       ret = ustctl_create_trace(sock, "auto");
+       ret = ustctl_create_trace(sock, trace->name);
        if (ret < 0) {
                ret = LTTCOMM_CREATE_FAIL;
                goto error;
@@ -326,6 +331,7 @@ static int ust_create_trace(pid_t pid)
        /* Check if current session is valid */
        if (current_session) {
                cds_list_add(&trace->list, &current_session->ust_traces);
+               current_session->ust_trace_count++;
        }
 
 error:
@@ -497,6 +503,25 @@ static int process_client_msg(int sock, struct lttcomm_session_msg *lsm)
                        /* No auxiliary data so only send the llm struct. */
                        goto end;
                }
+               case LTTNG_LIST_TRACES:
+               {
+                       unsigned int trace_count = get_trace_count_per_session(current_session);
+
+                       if (trace_count == 0) {
+                               ret = LTTCOMM_NO_TRACE;
+                               goto end;
+                       }
+
+                       buf_size = setup_data_buffer(&send_buf,
+                                       sizeof(struct lttng_trace) * trace_count, &llm);
+                       if (buf_size < 0) {
+                               ret = LTTCOMM_FATAL;
+                               goto end;
+                       }
+
+                       get_traces_per_session(current_session, (struct lttng_trace *)(send_buf + header_size));
+                       break;
+               }
                case UST_CREATE_TRACE:
                {
                        ret = ust_create_trace(lsm->pid);

diff --git a/ltt-sessiond/session.c b/ltt-sessiond/session.c
index da1ceee4ac97b10b23f2fc7597bd9f1bcb79e452..bf5f618a8ef34a7c7209806671ab7ed5feafb425 100644 (file)
--- a/ltt-sessiond/session.c
+++ b/ltt-sessiond/session.c
@@ -198,11 +198,15 @@ int create_session(char *name, uuid_t *session_id)
         * NO consumer attach to that session yet.
         */
        new_session->ust_consumer = 0;
-       new_session->lttng_consumer = 0;
+       new_session->kernel_consumer = 0;
 
        /* Init list */
        CDS_INIT_LIST_HEAD(&new_session->ust_traces);
-       CDS_INIT_LIST_HEAD(&new_session->lttng_traces);
+       CDS_INIT_LIST_HEAD(&new_session->kernel_traces);
+
+       /* Set trace list counter */
+       new_session->ust_trace_count = 0;
+       new_session->kern_trace_count = 0;
 
        /* Add new session to the global session list */
        add_session_list(new_session);

diff --git a/ltt-sessiond/session.h b/ltt-sessiond/session.h
index 6bc7c47994f1d0e2df439a8dc87cf777fddbe274..00e8ef1e7b230e3ae2f62c97dfd6593c94f44c03 100644 (file)
--- a/ltt-sessiond/session.h
+++ b/ltt-sessiond/session.h
@@ -35,9 +35,11 @@ struct ltt_session {
        struct cds_list_head list;
        uuid_t uuid;
        struct cds_list_head ust_traces;
-       struct cds_list_head lttng_traces;
+       struct cds_list_head kernel_traces;
+       unsigned int ust_trace_count;
+       unsigned int kern_trace_count;
        pid_t ust_consumer;
-       pid_t lttng_consumer;
+       pid_t kernel_consumer;
 };
 
 /* Prototypes */

diff --git a/ltt-sessiond/trace.c b/ltt-sessiond/trace.c
index 7d9c40cc03c74b57c27d5a3f0b2ad326ad8210f9..c5d700fd1450b17d842c20a93eef220d75e83d5d 100644 (file)
--- a/ltt-sessiond/trace.c
+++ b/ltt-sessiond/trace.c
@@ -21,6 +21,7 @@
 #include <limits.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 #include <urcu/list.h>
 
 #include "lttngerr.h"
@@ -47,3 +48,52 @@ struct ltt_ust_trace *find_session_ust_trace_by_pid(struct ltt_session *session,
        return NULL;
 }
 
+/*
+ *  get_trace_count_per_session
+ *
+ *  Return the total count of traces (ust and kernel)
+ *  for the specified session.
+ */
+int get_trace_count_per_session(struct ltt_session *session)
+{
+       return session->ust_trace_count + session->kern_trace_count;
+}
+
+/*
+ *  get_traces_per_session
+ *
+ *  Fill the lttng_trace array of all the
+ *  available trace of the session.
+ */
+void get_traces_per_session(struct ltt_session *session, struct lttng_trace *traces)
+{
+       int i = 0;
+       struct ltt_ust_trace *ust_iter;
+       struct ltt_kernel_trace *kern_iter;
+       struct lttng_trace trace;
+
+       DBG("Getting userspace traces for session %s", session->name);
+
+       /* Getting userspace traces */
+       cds_list_for_each_entry(ust_iter, &session->ust_traces, list) {
+               trace.type = USERSPACE;
+               trace.pid = ust_iter->pid;
+               strncpy(trace.name, ust_iter->name, sizeof(trace.name));
+               trace.name[sizeof(trace.name) - 1] = '\0';
+               memcpy(&traces[i], &trace, sizeof(trace));
+               memset(&trace, 0, sizeof(trace));
+               i++;
+       }
+
+       DBG("Getting kernel traces for session %s", session->name);
+
+       /* Getting kernel traces */
+       cds_list_for_each_entry(kern_iter, &session->kernel_traces, list) {
+               trace.type = KERNEL;
+               strncpy(trace.name, kern_iter->name, sizeof(trace.name));
+               trace.name[sizeof(trace.name) - 1] = '\0';
+               memcpy(&traces[i], &trace, sizeof(trace));
+               memset(&trace, 0, sizeof(trace));
+               i++;
+       }
+}

diff --git a/ltt-sessiond/trace.h b/ltt-sessiond/trace.h
index 36b2f2270eef69bedd70aa570027da7f61660f22..755f8dfdf89bf5a954ddcbc2b34b4b931bf5d136 100644 (file)
--- a/ltt-sessiond/trace.h
+++ b/ltt-sessiond/trace.h
@@ -22,15 +22,16 @@
 #include "session.h"
 
 /* LTTng trace representation */
-struct ltt_lttng_trace {
+struct ltt_kernel_trace {
        struct cds_list_head list;
-       char trace_name[NAME_MAX];
+       char name[NAME_MAX];
        struct cds_list_head marker_list;
 };
 
 /* UST trace representation */
 struct ltt_ust_trace {
        struct cds_list_head list;
+       char name[NAME_MAX];
        int shmid;
        pid_t pid;
        struct cds_list_head markers;
@@ -43,5 +44,7 @@ struct ltt_ust_marker {
 };
 
 struct ltt_ust_trace *find_session_ust_trace_by_pid(struct ltt_session *session, pid_t pid);
+int get_trace_count_per_session(struct ltt_session *session);
+void get_traces_per_session(struct ltt_session *session, struct lttng_trace *traces);
 
 #endif /* _LTT_TRACE_H */

diff --git a/lttng/lttng.c b/lttng/lttng.c
index e538df2fd403f0eefaf2be2c58b3c8a04973067d..16487ff74a99cb2149bda0964af415ee2721868d 100644 (file)
--- a/lttng/lttng.c
+++ b/lttng/lttng.c
@@ -42,6 +42,7 @@ static char *progname;
 static int process_client_opt(void);
 static int process_opt_list_apps(void);
 static int process_opt_list_sessions(void);
+static int process_opt_list_traces(void);
 static int process_opt_create_session(void);
 static void sighandler(int sig);
 static int set_signal_handler(void);
@@ -80,6 +81,13 @@ static int process_client_opt(void)
                }
        }
 
+       if (opt_list_traces) {
+               ret = process_opt_list_traces();
+               if (ret < 0) {
+                       goto end;
+               }
+       }
+
        if (opt_create_session != NULL) {
                ret = process_opt_create_session();
                if (ret < 0) {
@@ -125,6 +133,45 @@ end:
        return ret;
 }
 
+/*
+ *  process_opt_list_traces
+ *
+ *  Get list of all traces for a specific session uuid.
+ */
+static int process_opt_list_traces(void)
+{
+       int ret, i;
+       uuid_t uuid;
+       struct lttng_trace *traces;
+
+       uuid_parse(opt_session_uuid, uuid);
+       ret = lttng_list_traces(&uuid, &traces);
+       if (ret < 0) {
+               goto error;
+       }
+
+       MSG("Userspace traces:");
+       for (i = 0; i < ret; i++) {
+               if (traces[i].type == USERSPACE) {
+                       MSG("\t%d) %s (pid: %d)", i, traces[i].name, traces[i].pid);
+               } else {
+                       break;
+               }
+       }
+
+       MSG("Kernel traces:");
+       for (;i < ret; i++) {
+               if (traces[i].type == KERNEL) {
+                       MSG("\t%d) %s", i, traces[i].name);
+               }
+       }
+
+       free(traces);
+
+error:
+       return ret;
+}
+
 /*
  *  process_opt_create_session
  *
@@ -265,8 +312,8 @@ not_running:
 static int validate_options(void)
 {
        if ((opt_session_uuid == NULL) &&
-                       (opt_create_trace || opt_start_trace)) {
-               ERR("Can't act on trace without a session ID.\nPlease specify using --session UUID");
+                       (opt_create_trace || opt_start_trace || opt_list_traces)) {
+               ERR("You need to specify a session UUID.\nPlease use --session UUID to do so.");
                goto error;
        }
 

diff --git a/lttng/lttng.h b/lttng/lttng.h
index 4f16c8d1f2715f216c8d33940dd2623f0bd75252..cb419681806b63119959a21eb9b4a7a1a1811a12 100644 (file)
--- a/lttng/lttng.h
+++ b/lttng/lttng.h
@@ -34,6 +34,7 @@ extern char *opt_destroy_session;
 extern int opt_list_apps;
 extern int opt_no_sessiond;
 extern int opt_list_session;
+extern int opt_list_traces;
 extern pid_t opt_create_trace;
 extern pid_t opt_start_trace;
 

diff --git a/lttng/options.c b/lttng/options.c
index 183c54dcf0757e2b74f658c0fb7c61804d21b4dd..1ed0aca7d38b07e7ebf903709a478324b5ee6c04 100644 (file)
--- a/lttng/options.c
+++ b/lttng/options.c
@@ -33,6 +33,7 @@ int opt_verbose = 0;
 int opt_list_apps = 0;
 int opt_no_sessiond = 0;
 int opt_list_session = 0;
+int opt_list_traces = 0;
 pid_t opt_create_trace = 0;
 pid_t opt_start_trace = 0;
 
@@ -50,6 +51,7 @@ static struct poptOption long_options[] = {
        {"kernel",                      0,              POPT_ARG_VAL,           &opt_trace_kernel, 1, 0, 0},
        {"list-apps",           'L',    POPT_ARG_VAL,           &opt_list_apps, 1, 0, 0},
        {"list-sessions",       'l',    POPT_ARG_VAL,           &opt_list_session, 1, 0, 0},
+       {"list-traces",         't',    POPT_ARG_VAL,           &opt_list_traces, 1, 0, 0},
        {"no-kernel",           0,              POPT_ARG_VAL,           &opt_trace_kernel, 0, 0, 0},
        {"no-sessiond",         0,              POPT_ARG_VAL,           &opt_no_sessiond, 1, 0, 0},
        {"quiet",                       'q',    POPT_ARG_VAL,           &opt_quiet, 1, 0, 0},
@@ -88,6 +90,7 @@ static void usage(FILE *ofp)
        //fprintf(ofp, "      --kernel               Enable kernel tracing\n");
        //fprintf(ofp, "      --no-kernel            Disable kernel tracing\n");
        fprintf(ofp, "  -L, --list-apps              List traceable UST applications\n");
+       fprintf(ofp, "  -t, --list-traces            List session's traces. Use -s to specify the session\n");
        fprintf(ofp, "  -C, --create-trace PID       Create trace for PID\n");
        fprintf(ofp, "      --start PID              Start trace for PID\n");
        fprintf(ofp, "\n");