X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fcommon%2Fspawn-viewer.cpp;fp=src%2Fcommon%2Fspawn-viewer.cpp;h=bcbc229a2f2760e83b2fe27fbe34193a50d16910;hp=0000000000000000000000000000000000000000;hb=a6bc4ca9d659caf016ef932fcd944029737ac57c;hpb=97535efaa975ca52bf02c2d5e76351bfd2e3defa diff --git a/src/common/spawn-viewer.cpp b/src/common/spawn-viewer.cpp new file mode 100644 index 000000000..bcbc229a2 --- /dev/null +++ b/src/common/spawn-viewer.cpp @@ -0,0 +1,255 @@ +/* + * Copyright (C) 2011 David Goulet + * Copyright (C) 2014 Mathieu Desnoyers + * Copyright (C) 2020 Francis Deslauriers + * + * SPDX-License-Identifier: GPL-2.0-only + * + */ + +#include +#include +#include +#include + +#include + +#include +#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, *saveptr = NULL; + + /* 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 = (char **) zmalloc(sizeof(char *) * (num_opts + 2)); + if (argv == NULL) { + goto error; + } + + token = strtok_r(opts, " ", &saveptr); + while (token != NULL) { + argv[i] = strdup(token); + if (argv[i] == NULL) { + goto error; + } + token = strtok_r(NULL, " ", &saveptr); + 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 = (char **) 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. + */ + LTTNG_ASSERT(ret != 0); +error: + free(argv); + return ret; +}