X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fbin%2Flttng%2Fcommands%2Fenable_events.c;h=f7c5553da55b211383e31fb0fe92c3c6083693d1;hp=e90db88d1ff86398104d1a70b4ea162f6e390c50;hb=bb77204a261b474f7b659247c5fda93de4e40b86;hpb=91744e14248d52e0a696df7d94024dce79fdd665 diff --git a/src/bin/lttng/commands/enable_events.c b/src/bin/lttng/commands/enable_events.c index e90db88d1..f7c5553da 100644 --- a/src/bin/lttng/commands/enable_events.c +++ b/src/bin/lttng/commands/enable_events.c @@ -28,8 +28,11 @@ #include #include +#include #include +#include +#include /* Mi dependancy */ #include @@ -51,6 +54,7 @@ static int opt_log4j; static int opt_python; static int opt_enable_all; static char *opt_probe; +static char *opt_userspace_probe; static char *opt_function; static char *opt_channel_name; static char *opt_filter; @@ -66,6 +70,7 @@ enum { OPT_HELP = 1, OPT_TRACEPOINT, OPT_PROBE, + OPT_USERSPACE_PROBE, OPT_FUNCTION, OPT_SYSCALL, OPT_USERSPACE, @@ -92,6 +97,7 @@ static struct poptOption long_options[] = { {"python", 'p', POPT_ARG_VAL, &opt_python, 1, 0, 0}, {"tracepoint", 0, POPT_ARG_NONE, 0, OPT_TRACEPOINT, 0, 0}, {"probe", 0, POPT_ARG_STRING, &opt_probe, OPT_PROBE, 0, 0}, + {"userspace-probe",0, POPT_ARG_STRING, &opt_userspace_probe, OPT_USERSPACE_PROBE, 0, 0}, {"function", 0, POPT_ARG_STRING, &opt_function, OPT_FUNCTION, 0, 0}, {"syscall", 0, POPT_ARG_NONE, 0, OPT_SYSCALL, 0, 0}, {"loglevel", 0, POPT_ARG_STRING, 0, OPT_LOGLEVEL, 0, 0}, @@ -173,6 +179,395 @@ end: return ret; } +/* + * Walk the directories in the PATH environment variable to find the target + * binary passed as parameter. + * + * On success, the full path of the binary is copied in binary_full_path out + * parameter. This buffer is allocated by the caller and must be at least + * LTTNG_PATH_MAX bytes long. + * On failure, returns -1; + */ +static int walk_command_search_path(const char *binary, char *binary_full_path) +{ + char *tentative_binary_path = NULL; + char *command_search_path = NULL; + char *curr_search_dir_end = NULL; + char *curr_search_dir = NULL; + struct stat stat_output; + int ret = 0; + + command_search_path = lttng_secure_getenv("PATH"); + if (!command_search_path) { + ret = -1; + goto end; + } + + /* + * Duplicate the $PATH string as the char pointer returned by getenv() should + * not be modified. + */ + command_search_path = strdup(command_search_path); + if (!command_search_path) { + ret = -1; + goto end; + } + + /* + * This char array is used to concatenate path to binary to look for + * the binary. + */ + tentative_binary_path = zmalloc(LTTNG_PATH_MAX * sizeof(char)); + if (!tentative_binary_path) { + ret = -1; + goto alloc_error; + } + + curr_search_dir = command_search_path; + do { + /* + * Split on ':'. The return value of this call points to the + * matching character. + */ + curr_search_dir_end = strchr(curr_search_dir, ':'); + if (curr_search_dir_end != NULL) { + /* + * Add a NULL byte to the end of the first token so it + * can be used as a string. + */ + curr_search_dir_end[0] = '\0'; + } + + /* Empty the tentative path */ + memset(tentative_binary_path, 0, LTTNG_PATH_MAX * sizeof(char)); + + /* + * Build the tentative path to the binary using the current + * search directory and the name of the binary. + */ + ret = snprintf(tentative_binary_path, LTTNG_PATH_MAX, "%s/%s", + curr_search_dir, binary); + if (ret < 0) { + goto free_binary_path; + } + if (ret < LTTNG_PATH_MAX) { + /* + * Use STAT(2) to see if the file exists. + */ + ret = stat(tentative_binary_path, &stat_output); + if (ret == 0) { + /* + * Verify that it is a regular file or a + * symlink and not a special file (e.g. + * device). + */ + if (S_ISREG(stat_output.st_mode) + || S_ISLNK(stat_output.st_mode)) { + /* + * Found a match, set the out parameter + * and return success. + */ + ret = lttng_strncpy(binary_full_path, + tentative_binary_path, + LTTNG_PATH_MAX); + if (ret == -1) { + ERR("Source path does not fit " + "in destination buffer."); + } + goto free_binary_path; + } + } + } + /* Go to the next entry in the $PATH variable. */ + curr_search_dir = curr_search_dir_end + 1; + } while (curr_search_dir_end != NULL); + +free_binary_path: + free(tentative_binary_path); +alloc_error: + free(command_search_path); +end: + return ret; +} + +/* + * Check if the symbol field passed by the user is in fact an address or an + * offset from a symbol. Those two instrumentation types are not supported yet. + * It's expected to be a common mistake because of the existing --probe option + * that does support these formats. + * + * Here are examples of these unsupported formats for the --userspace-probe + * option: + * elf:/path/to/binary:0x400430 + * elf:/path/to/binary:4194364 + * elf:/path/to/binary:my_symbol+0x323 + * elf:/path/to/binary:my_symbol+43 + */ +static int warn_userspace_probe_syntax(const char *symbol) +{ + unsigned long addr = 0; + size_t offset = 0; + int ret; + + /* Check if the symbol field is an hex address. */ + ret = sscanf(symbol, "0x%lx", &addr); + if (ret > 0) { + /* If there is a match, print a warning and return an error. */ + ERR("Userspace probe on address not supported yet."); + ret = CMD_UNSUPPORTED; + goto error; + } + + /* Check if the symbol field is an decimal address. */ + ret = sscanf(symbol, "%lu", &addr); + if (ret > 0) { + /* If there is a match, print a warning and return an error. */ + ERR("Userspace probe on address not supported yet."); + ret = CMD_UNSUPPORTED; + goto error; + } + + /* Check if the symbol field is symbol+hex_offset. */ + ret = sscanf(symbol, "%*[^+]+0x%lx", &offset); + if (ret > 0) { + /* If there is a match, print a warning and return an error. */ + ERR("Userspace probe on symbol+offset not supported yet."); + ret = CMD_UNSUPPORTED; + goto error; + } + + /* Check if the symbol field is symbol+decimal_offset. */ + ret = sscanf(symbol, "%*[^+]+%lu", &offset); + if (ret > 0) { + /* If there is a match, print a warning and return an error. */ + ERR("Userspace probe on symbol+offset not supported yet."); + ret = CMD_UNSUPPORTED; + goto error; + } + + ret = 0; + +error: + return ret; +} + +/* + * Parse userspace probe options + * Set the userspace probe fields in the lttng_event struct and set the + * target_path to the path to the binary. + */ +static int parse_userspace_probe_opts(struct lttng_event *ev, char *opt) +{ + int ret = CMD_SUCCESS; + int num_token; + char **tokens; + char *target_path = NULL; + char *unescaped_target_path = NULL; + char *real_target_path = NULL; + char *symbol_name = NULL, *probe_name = NULL, *provider_name = NULL; + struct lttng_userspace_probe_location *probe_location = NULL; + struct lttng_userspace_probe_location_lookup_method *lookup_method = + NULL; + + if (opt == NULL) { + ret = CMD_ERROR; + goto end; + } + + switch (ev->type) { + case LTTNG_EVENT_USERSPACE_PROBE: + break; + default: + assert(0); + } + + /* + * userspace probe fields are separated by ':'. + */ + tokens = strutils_split(opt, ':', 1); + num_token = strutils_array_of_strings_len(tokens); + + /* + * Early sanity check that the number of parameter is between 2 and 4 + * inclusively. + * elf:PATH:SYMBOL + * std:PATH:PROVIDER_NAME:PROBE_NAME + * PATH:SYMBOL (same behavior as ELF) + */ + if (num_token < 2 || num_token > 4) { + ret = CMD_ERROR; + goto end_string; + } + + /* + * Looking up the first parameter will tell the technique to use to + * interpret the userspace probe/function description. + */ + switch (num_token) { + case 2: + /* When the probe type is omitted we assume ELF for now. */ + case 3: + if (num_token == 3 && strcmp(tokens[0], "elf") == 0) { + target_path = tokens[1]; + symbol_name = tokens[2]; + } else if (num_token == 2) { + target_path = tokens[0]; + symbol_name = tokens[1]; + } else { + ret = CMD_ERROR; + goto end_string; + } + lookup_method = + lttng_userspace_probe_location_lookup_method_function_elf_create(); + if (!lookup_method) { + WARN("Failed to create ELF lookup method"); + ret = CMD_ERROR; + goto end_string; + } + break; + case 4: + if (strcmp(tokens[0], "sdt") == 0) { + target_path = tokens[1]; + provider_name = tokens[2]; + probe_name = tokens[3]; + } else { + ret = CMD_ERROR; + goto end_string; + } + lookup_method = + lttng_userspace_probe_location_lookup_method_tracepoint_sdt_create(); + if (!lookup_method) { + WARN("Failed to create ELF lookup method"); + ret = CMD_ERROR; + goto end_string; + } + break; + default: + ret = CMD_ERROR; + goto end_string; + } + + /* strutils_unescape_string allocates a new char *. */ + unescaped_target_path = strutils_unescape_string(target_path, 0); + if (!unescaped_target_path) { + ret = CMD_ERROR; + goto end_destroy_lookup_method; + } + + /* + * If there is not forward slash in the path. Walk the $PATH else + * expand. + */ + if (strchr(unescaped_target_path, '/') == NULL) { + /* Walk the $PATH variable to find the targeted binary. */ + real_target_path = zmalloc(LTTNG_PATH_MAX * sizeof(char)); + if (!real_target_path) { + PERROR("Error allocating path buffer"); + ret = CMD_ERROR; + goto end_destroy_lookup_method; + } + ret = walk_command_search_path(unescaped_target_path, real_target_path); + if (ret) { + ERR("Binary not found."); + ret = CMD_ERROR; + goto end_destroy_lookup_method; + } + } else { + /* + * Expand references to `/./` and `/../`. This function does not check + * if the file exists. This call returns an allocated buffer on + * success. + */ + real_target_path = utils_expand_path_keep_symlink(unescaped_target_path); + if (!real_target_path) { + ERR("Error expanding the path to binary."); + ret = CMD_ERROR; + goto end_destroy_lookup_method; + } + + /* + * Check if the file exists using access(2). If it does not, walk the + * $PATH. + */ + ret = access(real_target_path, F_OK); + if (ret) { + ERR("Cannot find binary at path: %s.", real_target_path); + ret = CMD_ERROR; + goto end_destroy_lookup_method; + } + } + + switch (lttng_userspace_probe_location_lookup_method_get_type(lookup_method)) { + case LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_FUNCTION_ELF: + /* + * Check for common mistakes in userspace probe description syntax. + */ + ret = warn_userspace_probe_syntax(symbol_name); + if (ret) { + goto end_destroy_lookup_method; + } + + probe_location = lttng_userspace_probe_location_function_create( + real_target_path, symbol_name, lookup_method); + if (!probe_location) { + WARN("Failed to create function probe location"); + ret = CMD_ERROR; + goto end_destroy_lookup_method; + } + + /* Ownership transferred to probe_location. */ + lookup_method = NULL; + + ret = lttng_event_set_userspace_probe_location(ev, probe_location); + if (ret) { + WARN("Failed to set probe location on event"); + ret = CMD_ERROR; + goto end_destroy_location; + } + break; + case LTTNG_USERSPACE_PROBE_LOCATION_LOOKUP_METHOD_TYPE_TRACEPOINT_SDT: + probe_location = lttng_userspace_probe_location_tracepoint_create( + real_target_path, provider_name, probe_name, lookup_method); + if (!probe_location) { + WARN("Failed to create function probe location"); + ret = CMD_ERROR; + goto end_destroy_lookup_method; + } + + /* Ownership transferred to probe_location. */ + lookup_method = NULL; + + ret = lttng_event_set_userspace_probe_location(ev, probe_location); + if (ret) { + WARN("Failed to set probe location on event"); + ret = CMD_ERROR; + goto end_destroy_location; + } + break; + default: + ret = CMD_ERROR; + goto end_destroy_lookup_method; + } + + /* Successful parsing, now clean up everything and return. */ + goto end_string; + +end_destroy_location: + lttng_userspace_probe_location_destroy(probe_location); +end_destroy_lookup_method: + lttng_userspace_probe_location_lookup_method_destroy(lookup_method); +end_string: + strutils_free_null_terminated_array_of_strings(tokens); + /* + * Freeing both char * here makes the error handling simplier. free() + * performs not action if the pointer is NULL. + */ + free(real_target_path); + free(unescaped_target_path); +end: + return ret; +} + /* * Maps LOG4j loglevel from string to value */ @@ -640,6 +1035,30 @@ static int enable_events(char *session_name) } } + /* + * Adding a filter to a probe, function or userspace-probe would be + * denied by the kernel tracer as it's not supported at the moment. We + * do an early check here to warn the user. + */ + if (opt_filter && opt_kernel) { + switch (opt_event_type) { + case LTTNG_EVENT_ALL: + case LTTNG_EVENT_TRACEPOINT: + case LTTNG_EVENT_SYSCALL: + break; + case LTTNG_EVENT_PROBE: + case LTTNG_EVENT_USERSPACE_PROBE: + case LTTNG_EVENT_FUNCTION: + ERR("Filter expressions are not supported for %s events", + get_event_type_str(opt_event_type)); + ret = CMD_ERROR; + goto error; + default: + ret = CMD_UNDEFINED; + goto error; + } + } + channel_name = opt_channel_name; handle = lttng_create_handle(session_name, &dom); @@ -944,6 +1363,25 @@ static int enable_events(char *session_name) goto error; } break; + case LTTNG_EVENT_USERSPACE_PROBE: + ret = parse_userspace_probe_opts(ev, opt_userspace_probe); + if (ret) { + switch (ret) { + case CMD_UNSUPPORTED: + /* + * Error message describing + * what is not supported was + * printed in the function. + */ + break; + case CMD_ERROR: + default: + ERR("Unable to parse userspace probe options"); + break; + } + goto error; + } + break; case LTTNG_EVENT_FUNCTION: ret = parse_probe_opts(ev, opt_function); if (ret) { @@ -978,6 +1416,7 @@ static int enable_events(char *session_name) case LTTNG_EVENT_PROBE: case LTTNG_EVENT_FUNCTION: case LTTNG_EVENT_SYSCALL: + case LTTNG_EVENT_USERSPACE_PROBE: default: ERR("Event type not available for user-space tracing"); ret = CMD_UNSUPPORTED; @@ -1091,6 +1530,12 @@ static int enable_events(char *session_name) error = 1; break; } + case LTTNG_ERR_SDT_PROBE_SEMAPHORE: + ERR("SDT probes %s guarded by semaphores are not supported (channel %s, session %s)", + event_name, print_channel_name(channel_name), + session_name); + error = 1; + break; default: ERR("Event %s%s: %s (channel %s, session %s)", event_name, exclusion_string, @@ -1290,6 +1735,9 @@ int cmd_enable_events(int argc, const char **argv) case OPT_PROBE: opt_event_type = LTTNG_EVENT_PROBE; break; + case OPT_USERSPACE_PROBE: + opt_event_type = LTTNG_EVENT_USERSPACE_PROBE; + break; case OPT_FUNCTION: opt_event_type = LTTNG_EVENT_FUNCTION; break;