Prevent channel buffer allocation larger than memory

[lttng-tools.git] / src / lib / lttng-ctl / lttng-ctl.c

diff --git a/src/lib/lttng-ctl/lttng-ctl.c b/src/lib/lttng-ctl/lttng-ctl.c
index b0fe8ab74af65ad5565d184cf304cb6da82f4dd1..165fef4dc5c412392fe49daec62be947d4de3853 100644 (file)
--- a/src/lib/lttng-ctl/lttng-ctl.c
+++ b/src/lib/lttng-ctl/lttng-ctl.c
@@ -287,6 +287,50 @@ end:
        return ret;
 }
 
+static int check_enough_available_memory(size_t num_bytes_requested_per_cpu)
+{
+       int ret;
+       long num_cpu;
+       size_t best_mem_info;
+       size_t num_bytes_requested_total;
+
+       /*
+        * Get the number of CPU currently online to compute the amount of
+        * memory needed to create a buffer for every CPU.
+        */
+       num_cpu = sysconf(_SC_NPROCESSORS_ONLN);
+       if (num_cpu == -1) {
+               goto error;
+       }
+
+       num_bytes_requested_total = num_bytes_requested_per_cpu * num_cpu;
+
+       /*
+        * Try to get the `MemAvail` field of `/proc/meminfo`. This is the most
+        * reliable estimate we can get but it is only exposed by the kernel
+        * since 3.14. (See Linux kernel commit:
+        * 34e431b0ae398fc54ea69ff85ec700722c9da773)
+        */
+       ret = utils_get_memory_available(&best_mem_info);
+       if (ret >= 0) {
+               goto success;
+       }
+
+       /*
+        * As a backup plan, use `MemTotal` field of `/proc/meminfo`. This
+        * is a sanity check for obvious user error.
+        */
+       ret = utils_get_memory_total(&best_mem_info);
+       if (ret >= 0) {
+               goto success;
+       }
+
+error:
+       return -1;
+success:
+       return best_mem_info >= num_bytes_requested_total;
+}
+
 /*
  * Try connect to session daemon with sock_path.
  *
@@ -1475,6 +1519,7 @@ int lttng_enable_channel(struct lttng_handle *handle,
                struct lttng_channel *in_chan)
 {
        struct lttcomm_session_msg lsm;
+       size_t total_buffer_size_needed_per_cpu = 0;
 
        /* NULL arguments are forbidden. No default values. */
        if (handle == NULL || in_chan == NULL) {
@@ -1510,6 +1555,16 @@ int lttng_enable_channel(struct lttng_handle *handle,
                memcpy(&lsm.u.channel.extended, extended, sizeof(*extended));
        }
 
+       /*
+        * Verify that the amount of memory required to create the requested
+        * buffer is available on the system at the moment.
+        */
+       total_buffer_size_needed_per_cpu = lsm.u.channel.chan.attr.num_subbuf *
+               lsm.u.channel.chan.attr.subbuf_size;
+       if (!check_enough_available_memory(total_buffer_size_needed_per_cpu)) {
+               return -LTTNG_ERR_NOMEM;
+       }
+
        lsm.cmd_type = LTTNG_ENABLE_CHANNEL;
        lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
 
@@ -2114,6 +2169,7 @@ int lttng_list_events(struct lttng_handle *handle,
                                        ext_comm->nb_exclusions * LTTNG_SYMBOL_NAME_LEN);
                        if (ret) {
                                ret = -LTTNG_ERR_NOMEM;
+                               goto free_dynamic_buffer;
                        }
                        comm_ext_at += ext_comm->nb_exclusions * LTTNG_SYMBOL_NAME_LEN;
                }
@@ -2743,6 +2799,9 @@ int lttng_list_tracker_pids(struct lttng_handle *handle,
                return ret;
        }
        nr_pids = ret / sizeof(int32_t);
+       if (nr_pids > 0 && !pids) {
+               return -LTTNG_ERR_UNK;
+       }
        if (nr_pids == 1 && pids[0] == -1) {
                free(pids);
                pids = NULL;
@@ -2889,50 +2948,6 @@ end:
        return ret;
 }
 
-int lttng_session_get_current_archive_location(const char *session_name,
-               char **chunk_path)
-{
-       struct lttcomm_session_msg lsm;
-       struct lttng_session_get_current_output_return *output_return = NULL;
-       int ret;
-       size_t path_len;
-
-       memset(&lsm, 0, sizeof(lsm));
-       lsm.cmd_type = LTTNG_SESSION_GET_CURRENT_OUTPUT;
-       ret = lttng_strncpy(lsm.session.name, session_name,
-                       sizeof(lsm.session.name));
-       if (ret) {
-               ret = -LTTNG_ERR_INVALID;
-               goto end;
-       }
-
-       ret = lttng_ctl_ask_sessiond(&lsm, (void **) &output_return);
-       if (ret < 0) {
-               ret = -1;
-               goto end;
-       }
-
-       path_len = lttng_strnlen(output_return->path,
-                       sizeof(output_return->path));
-       if (path_len == 0 || path_len == sizeof(output_return->path)) {
-               ret = -LTTNG_ERR_NO_SESSION_OUTPUT;
-               goto end;
-       }
-
-       *chunk_path = zmalloc(path_len + 1);
-       if (!*chunk_path) {
-               ret = -1;
-               goto end;
-       }
-       memcpy(*chunk_path, output_return->path, path_len);
-
-       ret = 0;
-
-end:
-       free(output_return);
-       return ret;
-}
-
 /*
  * lib constructor.
  */