Clarify kernel version check error messages

[lttng-tools.git] / src / bin / lttng-sessiond / kernel.c

diff --git a/src/bin/lttng-sessiond/kernel.c b/src/bin/lttng-sessiond/kernel.c
index 45d958546f2cae75d938a8960af3c3fd5690be64..2c5b36541f3d275d2995e74d6b6452445628f217 100644 (file)
--- a/src/bin/lttng-sessiond/kernel.c
+++ b/src/bin/lttng-sessiond/kernel.c
@@ -187,6 +187,7 @@ int kernel_create_event(struct lttng_event *ev,
        assert(ev);
        assert(channel);
 
+       /* We pass ownership of filter_expression and filter */
        event = trace_kernel_create_event(ev, filter_expression,
                        filter);
        if (event == NULL) {
@@ -378,16 +379,46 @@ error:
 
 int kernel_track_pid(struct ltt_kernel_session *session, int pid)
 {
+       int ret;
+
        DBG("Kernel track PID %d for session id %" PRIu64 ".",
                        pid, session->id);
-       return kernctl_track_pid(session->fd, pid);
+       ret = kernctl_track_pid(session->fd, pid);
+       if (!ret) {
+               return LTTNG_OK;
+       }
+       switch (errno) {
+       case EINVAL:
+               return LTTNG_ERR_INVALID;
+       case ENOMEM:
+               return LTTNG_ERR_NOMEM;
+       case EEXIST:
+               return LTTNG_ERR_PID_TRACKED;
+       default:
+               return LTTNG_ERR_UNK;
+       }
 }
 
 int kernel_untrack_pid(struct ltt_kernel_session *session, int pid)
 {
+       int ret;
+
        DBG("Kernel untrack PID %d for session id %" PRIu64 ".",
                        pid, session->id);
-       return kernctl_untrack_pid(session->fd, pid);
+       ret = kernctl_untrack_pid(session->fd, pid);
+       if (!ret) {
+               return LTTNG_OK;
+       }
+       switch (errno) {
+       case EINVAL:
+               return LTTNG_ERR_INVALID;
+       case ENOMEM:
+               return LTTNG_ERR_NOMEM;
+       case ENOENT:
+               return LTTNG_ERR_PID_NOT_TRACKED;
+       default:
+               return LTTNG_ERR_UNK;
+       }
 }
 
 ssize_t kernel_list_tracker_pids(struct ltt_kernel_session *session,
@@ -799,7 +830,7 @@ int kernel_validate_version(int tracer_fd)
 
        ret = kernctl_tracer_version(tracer_fd, &version);
        if (ret < 0) {
-               ERR("Failed at getting the lttng-modules version");
+               ERR("Failed to retrieve the lttng-modules version");
                goto error;
        }
 
@@ -811,11 +842,11 @@ int kernel_validate_version(int tracer_fd)
        }
        ret = kernctl_tracer_abi_version(tracer_fd, &abi_version);
        if (ret < 0) {
-               ERR("Failed at getting lttng-modules ABI version");
+               ERR("Failed to retrieve lttng-modules ABI version");
                goto error;
        }
        if (abi_version.major != LTTNG_MODULES_ABI_MAJOR_VERSION) {
-               ERR("Kernel tracer ABI version (%d.%d) is not compatible with expected ABI major version (%d.*)",
+               ERR("Kernel tracer ABI version (%d.%d) does not match the expected ABI major version (%d.*)",
                        abi_version.major, abi_version.minor,
                        LTTNG_MODULES_ABI_MAJOR_VERSION);
                goto error;
@@ -829,6 +860,7 @@ error_version:
        ret = -1;
 
 error:
+       ERR("Kernel tracer version check failed; kernel tracing will not be available");
        return ret;
 }