Fix: possible null dereference on communication error
[lttng-tools.git] / src / lib / lttng-ctl / lttng-ctl.c
index 37b2531028c83930537f796bdaca041b83df3bd4..f503fd1cbf42a25660a990d869c7adeb467cc823 100644 (file)
 #include <unistd.h>
 
 #include <common/common.h>
+#include <common/compat/string.h>
 #include <common/defaults.h>
 #include <common/sessiond-comm/sessiond-comm.h>
 #include <common/uri.h>
 #include <common/utils.h>
+#include <common/dynamic-buffer.h>
 #include <lttng/lttng.h>
 #include <lttng/health-internal.h>
 #include <lttng/trigger/trigger-internal.h>
 #include <lttng/endpoint.h>
 #include <lttng/channel-internal.h>
+#include <lttng/event-internal.h>
+#include <lttng/userspace-probe-internal.h>
 
 #include "filter/filter-ast.h"
 #include "filter/filter-parser.h"
@@ -176,6 +180,35 @@ end:
        return ret;
 }
 
+/*
+ * Send file descriptors to the session daemon.
+ *
+ * On success, returns the number of bytes sent (>=0)
+ * On error, returns -1
+ */
+static int send_session_fds(const int *fds, size_t nb_fd)
+{
+       int ret;
+
+       if (!connected) {
+               ret = -LTTNG_ERR_NO_SESSIOND;
+               goto end;
+       }
+
+       if (!fds || !nb_fd) {
+               ret = 0;
+               goto end;
+       }
+
+       ret = lttcomm_send_fds_unix_sock(sessiond_socket, fds, nb_fd);
+       if (ret < 0) {
+               ret = -LTTNG_ERR_FATAL;
+       }
+
+end:
+       return ret;
+}
+
 /*
  * Receive data from the sessiond socket.
  *
@@ -445,15 +478,16 @@ end:
 
 /*
  * Ask the session daemon a specific command and put the data into buf.
- * Takes extra var. len. data as input to send to the session daemon.
+ * Takes extra var. len. data and file descriptors as input to send to the
+ * session daemon.
  *
  * Return size of data (only payload, not header) or a negative error code.
  */
 LTTNG_HIDDEN
-int lttng_ctl_ask_sessiond_varlen(struct lttcomm_session_msg *lsm,
-               const void *vardata, size_t vardata_len,
-               void **user_payload_buf, void **user_cmd_header_buf,
-               size_t *user_cmd_header_len)
+int lttng_ctl_ask_sessiond_fds_varlen(struct lttcomm_session_msg *lsm,
+               const int *fds, size_t nb_fd, const void *vardata,
+               size_t vardata_len, void **user_payload_buf,
+               void **user_cmd_header_buf, size_t *user_cmd_header_len)
 {
        int ret;
        size_t payload_len;
@@ -478,6 +512,13 @@ int lttng_ctl_ask_sessiond_varlen(struct lttcomm_session_msg *lsm,
                goto end;
        }
 
+       /* Send fds */
+       ret = send_session_fds(fds, nb_fd);
+       if (ret < 0) {
+               /* Ret value is a valid lttng error code. */
+               goto end;
+       }
+
        /* Get header from data transmission */
        ret = recv_data_sessiond(&llm, sizeof(llm));
        if (ret < 0) {
@@ -987,10 +1028,14 @@ int lttng_enable_event_with_exclusions(struct lttng_handle *handle,
                int exclusion_count, char **exclusion_list)
 {
        struct lttcomm_session_msg lsm;
-       char *varlen_data;
-       int ret = 0;
+       struct lttng_dynamic_buffer send_buffer;
+       int ret = 0, i, fd_to_send = -1;
+       bool send_fd = false;
        unsigned int free_filter_expression = 0;
        struct filter_parser_ctx *ctx = NULL;
+
+       memset(&send_buffer, 0, sizeof(send_buffer));
+
        /*
         * Cast as non-const since we may replace the filter expression
         * by a dynamically allocated string. Otherwise, the original
@@ -1039,22 +1084,11 @@ int lttng_enable_event_with_exclusions(struct lttng_handle *handle,
        lsm.u.enable.exclusion_count = exclusion_count;
        lsm.u.enable.bytecode_len = 0;
 
-       /*
-        * For the JUL domain, a filter is enforced except for the enable all
-        * event. This is done to avoid having the event in all sessions thus
-        * filtering by logger name.
-        */
-       if (exclusion_count == 0 && filter_expression == NULL &&
-                       (handle->domain.type != LTTNG_DOMAIN_JUL &&
-                               handle->domain.type != LTTNG_DOMAIN_LOG4J &&
-                               handle->domain.type != LTTNG_DOMAIN_PYTHON)) {
-               goto ask_sessiond;
-       }
-
        /*
         * We have either a filter or some exclusions, so we need to set up
         * a variable-length memory block from where to send the data.
         */
+       lttng_dynamic_buffer_init(&send_buffer);
 
        /* Parse filter expression. */
        if (filter_expression != NULL || handle->domain.type == LTTNG_DOMAIN_JUL
@@ -1092,41 +1126,82 @@ int lttng_enable_event_with_exclusions(struct lttng_handle *handle,
                }
        }
 
-       varlen_data = zmalloc(lsm.u.enable.bytecode_len
+       ret = lttng_dynamic_buffer_set_capacity(&send_buffer,
+                       lsm.u.enable.bytecode_len
                        + lsm.u.enable.expression_len
                        + LTTNG_SYMBOL_NAME_LEN * exclusion_count);
-       if (!varlen_data) {
+       if (ret) {
                ret = -LTTNG_ERR_EXCLUSION_NOMEM;
                goto mem_error;
        }
 
        /* Put exclusion names first in the data. */
-       while (exclusion_count--) {
-               strncpy(varlen_data + LTTNG_SYMBOL_NAME_LEN * exclusion_count,
-                       *(exclusion_list + exclusion_count),
-                       LTTNG_SYMBOL_NAME_LEN - 1);
+       for (i = 0; i < exclusion_count; i++) {
+               size_t exclusion_len;
+
+               exclusion_len = lttng_strnlen(*(exclusion_list + i),
+                               LTTNG_SYMBOL_NAME_LEN);
+               if (exclusion_len == LTTNG_SYMBOL_NAME_LEN) {
+                       /* Exclusion is not NULL-terminated. */
+                       ret = -LTTNG_ERR_INVALID;
+                       goto mem_error;
+               }
+
+               ret = lttng_dynamic_buffer_append(&send_buffer,
+                               *(exclusion_list + i),
+                               LTTNG_SYMBOL_NAME_LEN);
+               if (ret) {
+                       goto mem_error;
+               }
        }
+
        /* Add filter expression next. */
-       if (lsm.u.enable.expression_len != 0) {
-               memcpy(varlen_data
-                       + LTTNG_SYMBOL_NAME_LEN * lsm.u.enable.exclusion_count,
-                       filter_expression,
-                       lsm.u.enable.expression_len);
+       if (filter_expression) {
+               ret = lttng_dynamic_buffer_append(&send_buffer,
+                               filter_expression, lsm.u.enable.expression_len);
+               if (ret) {
+                       goto mem_error;
+               }
        }
        /* Add filter bytecode next. */
        if (ctx && lsm.u.enable.bytecode_len != 0) {
-               memcpy(varlen_data
-                       + LTTNG_SYMBOL_NAME_LEN * lsm.u.enable.exclusion_count
-                       + lsm.u.enable.expression_len,
-                       &ctx->bytecode->b,
-                       lsm.u.enable.bytecode_len);
+               ret = lttng_dynamic_buffer_append(&send_buffer,
+                               &ctx->bytecode->b, lsm.u.enable.bytecode_len);
+               if (ret) {
+                       goto mem_error;
+               }
        }
+       if (ev->extended.ptr) {
+               struct lttng_event_extended *ev_ext =
+                       (struct lttng_event_extended *) ev->extended.ptr;
+
+               if (ev_ext->probe_location) {
+                       /*
+                        * lttng_userspace_probe_location_serialize returns the
+                        * number of bytes that was appended to the buffer.
+                        */
+                       ret = lttng_userspace_probe_location_serialize(
+                               ev_ext->probe_location, &send_buffer,
+                               &fd_to_send);
+                       if (ret < 0) {
+                               goto mem_error;
+                       }
 
-       ret = lttng_ctl_ask_sessiond_varlen_no_cmd_header(&lsm, varlen_data,
-                       (LTTNG_SYMBOL_NAME_LEN * lsm.u.enable.exclusion_count) +
-                       lsm.u.enable.bytecode_len + lsm.u.enable.expression_len,
-                       NULL);
-       free(varlen_data);
+                       send_fd = fd_to_send >= 0;
+                       /*
+                        * Set the size of the userspace probe location element
+                        * of the buffer so that the receiving side knows where
+                        * to split it.
+                        */
+                       lsm.u.enable.userspace_probe_location_len = ret;
+               }
+       }
+
+       ret = lttng_ctl_ask_sessiond_fds_varlen(&lsm,
+                       send_fd ? &fd_to_send : NULL,
+                       send_fd ? 1 : 0,
+                       send_buffer.size ? send_buffer.data : NULL,
+                       send_buffer.size, NULL, NULL, 0);
 
 mem_error:
        if (filter_expression && ctx) {
@@ -1148,6 +1223,7 @@ error:
         * Return directly to the caller and don't ask the sessiond since
         * something went wrong in the parsing of data above.
         */
+       lttng_dynamic_buffer_reset(&send_buffer);
        return ret;
 
 ask_sessiond:
@@ -1858,7 +1934,10 @@ int lttng_list_events(struct lttng_handle *handle,
        struct lttcomm_event_command_header *cmd_header = NULL;
        size_t cmd_header_len;
        uint32_t nb_events, i;
-       void *extended_at;
+       void *comm_ext_at;
+       char *reception_buffer = NULL;
+       struct lttng_dynamic_buffer listing;
+       size_t storage_req;
 
        /* Safety check. An handle and channel name are mandatory */
        if (handle == NULL || channel_name == NULL) {
@@ -1873,43 +1952,220 @@ int lttng_list_events(struct lttng_handle *handle,
                        sizeof(lsm.u.list.channel_name));
        lttng_ctl_copy_lttng_domain(&lsm.domain, &handle->domain);
 
-       ret = lttng_ctl_ask_sessiond_varlen(&lsm, NULL, 0, (void **) events,
-               (void **) &cmd_header, &cmd_header_len);
+       ret = lttng_ctl_ask_sessiond_fds_varlen(&lsm, NULL, 0, NULL, 0,
+               (void **) &reception_buffer, (void **) &cmd_header,
+               &cmd_header_len);
        if (ret < 0) {
-               goto error;
+               goto end;
+       }
+
+       if (!cmd_header) {
+               ret = -LTTNG_ERR_UNK;
+               goto end;
        }
 
        /* Set number of events and free command header */
        nb_events = cmd_header->nb_events;
        if (nb_events > INT_MAX) {
                ret = -EOVERFLOW;
-               goto error;
+               goto end;
        }
-       ret = (int) nb_events;
        free(cmd_header);
        cmd_header = NULL;
 
-       /* Set extended info pointers */
-       extended_at = ((void*) (*events)) +
-                       nb_events * sizeof(struct lttng_event);
+       /*
+        * The buffer that is returned must contain a "flat" version of
+        * the events that are returned. In other words, all pointers
+        * within an lttng_event must point to a location within the returned
+        * buffer so that the user may free everything by simply calling free()
+        * on the returned buffer. This is needed in order to maintain API
+        * compatibility.
+        *
+        * A first pass is performed to compute the size of the buffer that
+        * must be allocated. A second pass is then performed to setup
+        * the returned events so that their members always point within the
+        * buffer.
+        *
+        * The layout of the returned buffer is as follows:
+        *   - struct lttng_event[nb_events],
+        *   - nb_events times the following:
+        *     - struct lttng_event_extended,
+        *     - flattened version of userspace_probe_location
+        *     - filter_expression
+        *     - exclusions
+        *     - padding to align to 64-bits
+        */
+       comm_ext_at = reception_buffer +
+               (nb_events * sizeof(struct lttng_event));
+       storage_req = nb_events * sizeof(struct lttng_event);
 
        for (i = 0; i < nb_events; i++) {
-               struct lttcomm_event_extended_header *ext_header;
-               struct lttng_event *event = &(*events)[i];
+               struct lttcomm_event_extended_header *ext_comm =
+                       (struct lttcomm_event_extended_header *) comm_ext_at;
+               int probe_storage_req = 0;
+
+               comm_ext_at += sizeof(*ext_comm);
+               comm_ext_at += ext_comm->filter_len;
+               comm_ext_at +=
+                       ext_comm->nb_exclusions * LTTNG_SYMBOL_NAME_LEN;
+
+               if (ext_comm->userspace_probe_location_len) {
+                       struct lttng_userspace_probe_location *probe_location = NULL;
+                       struct lttng_buffer_view probe_location_view;
+
+                       probe_location_view = lttng_buffer_view_init(
+                                       comm_ext_at, 0,
+                                       ext_comm->userspace_probe_location_len);
+
+                       /*
+                        * Create a temporary userspace probe location to
+                        * determine the size needed by a "flattened" version
+                        * of that same probe location.
+                        */
+                       ret = lttng_userspace_probe_location_create_from_buffer(
+                                       &probe_location_view, &probe_location);
+                       if (ret < 0) {
+                               ret = -LTTNG_ERR_PROBE_LOCATION_INVAL;
+                               goto end;
+                       }
 
-               event->extended.ptr = extended_at;
-               ext_header =
-                       (struct lttcomm_event_extended_header *) extended_at;
-               extended_at += sizeof(*ext_header);
-               extended_at += ext_header->filter_len;
-               extended_at +=
-                       ext_header->nb_exclusions * LTTNG_SYMBOL_NAME_LEN;
+                       ret = lttng_userspace_probe_location_flatten(
+                                       probe_location, NULL);
+                       lttng_userspace_probe_location_destroy(probe_location);
+                       if (ret < 0) {
+                               ret = -LTTNG_ERR_PROBE_LOCATION_INVAL;
+                               goto end;
+                       }
+
+                       probe_storage_req = ret;
+                       comm_ext_at += ext_comm->userspace_probe_location_len;
+                       ret = 0;
+               }
+
+               storage_req += sizeof(struct lttng_event_extended);
+               storage_req += ext_comm->filter_len;
+               storage_req += ext_comm->nb_exclusions * LTTNG_SYMBOL_NAME_LEN;
+               /* Padding to ensure the flat probe is aligned. */
+               storage_req = ALIGN_TO(storage_req, sizeof(uint64_t));
+               storage_req += probe_storage_req;
        }
 
-       return ret;
-error:
+       lttng_dynamic_buffer_init(&listing);
+       /*
+        * We must ensure that "listing" is never resized so as to preserve
+        * the validity of the flattened objects.
+        */
+       ret = lttng_dynamic_buffer_set_capacity(&listing, storage_req);
+       if (ret) {
+               ret = -LTTNG_ERR_NOMEM;
+               goto end;
+       }
+
+       ret = lttng_dynamic_buffer_append(&listing, reception_buffer,
+                       nb_events * sizeof(struct lttng_event));
+       if (ret) {
+               ret = -LTTNG_ERR_NOMEM;
+               goto free_dynamic_buffer;
+       }
+
+       comm_ext_at = reception_buffer +
+                       (nb_events * sizeof(struct lttng_event));
+       for (i = 0; i < nb_events; i++) {
+               struct lttng_event *event = (struct lttng_event *)
+                       (listing.data + (sizeof(struct lttng_event) * i));
+               struct lttcomm_event_extended_header *ext_comm =
+                       (struct lttcomm_event_extended_header *) comm_ext_at;
+               struct lttng_event_extended *event_extended =
+                       (struct lttng_event_extended *)
+                               (listing.data + listing.size);
+
+               /* Insert struct lttng_event_extended. */
+               ret = lttng_dynamic_buffer_set_size(&listing,
+                               listing.size + sizeof(*event_extended));
+               if (ret) {
+                       ret = -LTTNG_ERR_NOMEM;
+                       goto free_dynamic_buffer;
+               }
+               event->extended.ptr = event_extended;
+
+               comm_ext_at += sizeof(*ext_comm);
+
+               /* Insert filter expression. */
+               if (ext_comm->filter_len) {
+                       event_extended->filter_expression = listing.data +
+                                       listing.size;
+                       ret = lttng_dynamic_buffer_append(&listing, comm_ext_at,
+                                       ext_comm->filter_len);
+                       if (ret) {
+                               ret = -LTTNG_ERR_NOMEM;
+                               goto free_dynamic_buffer;
+                       }
+                       comm_ext_at += ext_comm->filter_len;
+               }
+
+               /* Insert exclusions. */
+               if (ext_comm->nb_exclusions) {
+                       event_extended->exclusions.count =
+                                       ext_comm->nb_exclusions;
+                       event_extended->exclusions.strings =
+                                       listing.data + listing.size;
+
+                       ret = lttng_dynamic_buffer_append(&listing,
+                                       comm_ext_at,
+                                       ext_comm->nb_exclusions * LTTNG_SYMBOL_NAME_LEN);
+                       if (ret) {
+                               ret = -LTTNG_ERR_NOMEM;
+                       }
+                       comm_ext_at += ext_comm->nb_exclusions * LTTNG_SYMBOL_NAME_LEN;
+               }
+
+               /* Insert padding to align to 64-bits. */
+               ret = lttng_dynamic_buffer_set_size(&listing,
+                               ALIGN_TO(listing.size, sizeof(uint64_t)));
+               if (ret) {
+                       ret = -LTTNG_ERR_NOMEM;
+                       goto free_dynamic_buffer;
+               }
+
+               /* Insert flattened userspace probe location. */
+               if (ext_comm->userspace_probe_location_len) {
+                       struct lttng_userspace_probe_location *probe_location = NULL;
+                       struct lttng_buffer_view probe_location_view;
+
+                       probe_location_view = lttng_buffer_view_init(
+                                       comm_ext_at, 0,
+                                       ext_comm->userspace_probe_location_len);
+
+                       ret = lttng_userspace_probe_location_create_from_buffer(
+                                       &probe_location_view, &probe_location);
+                       if (ret < 0) {
+                               ret = -LTTNG_ERR_PROBE_LOCATION_INVAL;
+                               goto free_dynamic_buffer;
+                       }
+
+                       event_extended->probe_location = (struct lttng_userspace_probe_location *)
+                                       (listing.data + listing.size);
+                       ret = lttng_userspace_probe_location_flatten(
+                                       probe_location, &listing);
+                       lttng_userspace_probe_location_destroy(probe_location);
+                       if (ret < 0) {
+                               ret = -LTTNG_ERR_PROBE_LOCATION_INVAL;
+                               goto free_dynamic_buffer;
+                       }
+
+                       comm_ext_at += ext_comm->userspace_probe_location_len;
+               }
+       }
+
+       /* Don't reset listing buffer as we return its content. */
+       *events = (struct lttng_event *) listing.data;
+       lttng_dynamic_buffer_init(&listing);
+       ret = (int) nb_events;
+free_dynamic_buffer:
+       lttng_dynamic_buffer_reset(&listing);
+end:
        free(cmd_header);
-       free(*events);
+       free(reception_buffer);
        return ret;
 }
 
@@ -2471,7 +2727,7 @@ int lttng_list_tracker_pids(struct lttng_handle *handle,
        int enabled = 1;
        struct lttcomm_session_msg lsm;
        size_t nr_pids;
-       int32_t *pids;
+       int32_t *pids = NULL;
 
        if (handle == NULL) {
                return -LTTNG_ERR_INVALID;
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