+/*
+ * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
+ * Copyright (C) 2014 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ * Copyright (C) 2020 Francis Deslauriers <francis.deslauriers@efficios.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-only
+ *
+ */
+
+#include <assert.h>
+#include <stdbool.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <errno.h>
+
+#include <lttng/constant.h>
+
+#include "error.h"
+#include "macros.h"
+#include "spawn-viewer.h"
+
+
+static const char *babeltrace_bin = CONFIG_BABELTRACE_BIN;
+static const char *babeltrace2_bin = CONFIG_BABELTRACE2_BIN;
+
+/*
+ * This is needed for each viewer since we are using execvp().
+ */
+static const char *babeltrace_opts[] = { "babeltrace" };
+static const char *babeltrace2_opts[] = { "babeltrace2" };
+
+/*
+ * Type is also use as the index in the viewers array. So please, make sure
+ * your enum value is in the right order in the array below.
+ */
+enum viewer_type {
+ VIEWER_BABELTRACE = 0,
+ VIEWER_BABELTRACE2 = 1,
+ VIEWER_USER_DEFINED = 2,
+};
+
+static const struct viewer {
+ const char *exec_name;
+ enum viewer_type type;
+} viewers[] = {
+ { "babeltrace", VIEWER_BABELTRACE },
+ { "babeltrace2", VIEWER_BABELTRACE2 },
+ { NULL, VIEWER_USER_DEFINED },
+};
+
+static const struct viewer *parse_viewer_option(const char *opt_viewer)
+{
+ if (opt_viewer == NULL) {
+ /* Default is babeltrace2 */
+ return &(viewers[VIEWER_BABELTRACE2]);
+ }
+
+ return &(viewers[VIEWER_USER_DEFINED]);
+}
+
+/*
+ * Alloc an array of string pointer from a simple string having all options
+ * seperated by spaces. Also adds the trace path to the arguments.
+ *
+ * The returning pointer is ready to be passed to execvp().
+ */
+static char **alloc_argv_from_user_opts(char *opts, const char *trace_path)
+{
+ int i = 0, ignore_space = 0;
+ unsigned int num_opts = 1;
+ char **argv, *token = opts;
+
+ /* Count number of arguments. */
+ do {
+ if (*token == ' ') {
+ /* Use to ignore consecutive spaces */
+ if (!ignore_space) {
+ num_opts++;
+ }
+ ignore_space = 1;
+ } else {
+ ignore_space = 0;
+ }
+ token++;
+ } while (*token != '\0');
+
+ /* Add two here for the NULL terminating element and trace path */
+ argv = zmalloc(sizeof(char *) * (num_opts + 2));
+ if (argv == NULL) {
+ goto error;
+ }
+
+ token = strtok(opts, " ");
+ while (token != NULL) {
+ argv[i] = strdup(token);
+ if (argv[i] == NULL) {
+ goto error;
+ }
+ token = strtok(NULL, " ");
+ i++;
+ }
+
+ argv[num_opts] = (char *) trace_path;
+ argv[num_opts + 1] = NULL;
+
+ return argv;
+
+error:
+ if (argv) {
+ for (i = 0; i < num_opts + 2; i++) {
+ free(argv[i]);
+ }
+ free(argv);
+ }
+
+ return NULL;
+}
+
+/*
+ * Alloc an array of string pointer from an array of strings. It also adds
+ * the trace path to the argv.
+ *
+ * The returning pointer is ready to be passed to execvp().
+ */
+static char **alloc_argv_from_local_opts(const char **opts, size_t opts_len,
+ const char *trace_path, bool opt_live_mode)
+{
+ char **argv;
+ size_t size, mem_len;
+
+ /* Add one for the NULL terminating element. */
+ mem_len = opts_len + 1;
+ if (opt_live_mode) {
+ /* Add 3 option for the live mode being "-i lttng-live URL". */
+ mem_len += 3;
+ } else {
+ /* Add option for the trace path. */
+ mem_len += 1;
+ }
+
+ size = sizeof(char *) * mem_len;
+
+ /* Add two here for the trace_path and the NULL terminating element. */
+ argv = zmalloc(size);
+ if (argv == NULL) {
+ goto error;
+ }
+
+ memcpy(argv, opts, sizeof(char *) * opts_len);
+
+ if (opt_live_mode) {
+ argv[opts_len] = (char *) "-i";
+ argv[opts_len + 1] = (char *) "lttng-live";
+ argv[opts_len + 2] = (char *) trace_path;
+ argv[opts_len + 3] = NULL;
+ } else {
+ argv[opts_len] = (char *) trace_path;
+ argv[opts_len + 1] = NULL;
+ }
+
+error:
+ return argv;
+}
+
+
+/*
+ * Spawn viewer with the trace directory path.
+ */
+int spawn_viewer(const char *trace_path, char *opt_viewer, bool opt_live_mode)
+{
+ int ret = 0;
+ struct stat status;
+ const char *viewer_bin = NULL;
+ const struct viewer *viewer;
+ char **argv = NULL;
+
+ /* Check for --viewer option. */
+ viewer = parse_viewer_option(opt_viewer);
+ if (viewer == NULL) {
+ ret = -1;
+ goto error;
+ }
+
+retry_viewer:
+ switch (viewer->type) {
+ case VIEWER_BABELTRACE2:
+ if (stat(babeltrace2_bin, &status) == 0) {
+ viewer_bin = babeltrace2_bin;
+ } else {
+ viewer_bin = viewer->exec_name;
+ }
+ argv = alloc_argv_from_local_opts(babeltrace2_opts,
+ ARRAY_SIZE(babeltrace2_opts), trace_path,
+ opt_live_mode);
+ break;
+ case VIEWER_BABELTRACE:
+ if (stat(babeltrace_bin, &status) == 0) {
+ viewer_bin = babeltrace_bin;
+ } else {
+ viewer_bin = viewer->exec_name;
+ }
+ argv = alloc_argv_from_local_opts(babeltrace_opts,
+ ARRAY_SIZE(babeltrace_opts), trace_path,
+ opt_live_mode);
+ break;
+ case VIEWER_USER_DEFINED:
+ argv = alloc_argv_from_user_opts(opt_viewer, trace_path);
+ if (argv) {
+ viewer_bin = argv[0];
+ }
+ break;
+ default:
+ abort();
+ }
+
+ if (argv == NULL || !viewer_bin) {
+ ret = -1;
+ goto error;
+ }
+
+ DBG("Using %s viewer", viewer_bin);
+
+ ret = execvp(viewer_bin, argv);
+ if (ret) {
+ if (errno == ENOENT && viewer->exec_name) {
+ if (viewer->type == VIEWER_BABELTRACE2) {
+ /* Fallback to legacy babeltrace. */
+ DBG("Default viewer \"%s\" not installed on the system, falling back to \"%s\"",
+ viewers[VIEWER_BABELTRACE2].exec_name,
+ viewers[VIEWER_BABELTRACE].exec_name);
+ viewer = &viewers[VIEWER_BABELTRACE];
+ free(argv);
+ argv = NULL;
+ goto retry_viewer;
+ } else {
+ ERR("Default viewer \"%s\" (and fallback \"%s\") not found on the system",
+ viewers[VIEWER_BABELTRACE2].exec_name,
+ viewers[VIEWER_BABELTRACE].exec_name);
+ }
+ } else {
+ PERROR("Failed to launch \"%s\" viewer", viewer_bin);
+ }
+ ret = -1;
+ goto error;
+ }
+
+ /*
+ * This function should never return if successfull because `execvp(3)`
+ * onle returns if an error has occurred.
+ */
+ assert(ret != 0);
+error:
+ free(argv);
+ return ret;
+}
projects / lttng-tools.git / commitdiff
