Fix: sessiond: assertion fails when getting name of trigger
[lttng-tools.git] / src / bin / lttng / commands / enable_events.c
index 62f99a1fcfc760e659a3ab1c3a0e775fc79dccec..f41dc9ecac7424e0a4edc458a982f00353646c95 100644 (file)
@@ -1,18 +1,8 @@
 /*
- * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
+ * Copyright (C) 2011 David Goulet <david.goulet@polymtl.ca>
  *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License, version 2 only,
- * as published by the Free Software Foundation.
+ * SPDX-License-Identifier: GPL-2.0-only
  *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License along
- * with this program; if not, write to the Free Software Foundation, Inc.,
- * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
 #define _LGPL_SOURCE
@@ -143,7 +133,7 @@ static int parse_probe_opts(struct lttng_event *ev, char *opt)
        }
 
        /* Check for symbol */
-       if (isalpha(name[0])) {
+       if (isalpha(name[0]) || name[0] == '_') {
                match = sscanf(opt, "%" LTTNG_SYMBOL_NAME_LEN_SCANF_IS_A_BROKEN_API "s",
                        name);
                if (match == 1) {
@@ -160,8 +150,13 @@ static int parse_probe_opts(struct lttng_event *ev, char *opt)
        /* Check for address */
        match = sscanf(opt, "%" S_HEX_LEN_SCANF_IS_A_BROKEN_API "s", s_hex);
        if (match > 0) {
-               if (*s_hex == '\0') {
-                       ERR("Invalid probe address %s", s_hex);
+               /*
+                * Return an error if the first character of the tentative
+                * address is NULL or not a digit. It can be "0" if the address
+                * is in hexadecimal and can be 1 to 9 if it's in decimal.
+                */
+               if (*s_hex == '\0' || !isdigit(*s_hex)) {
+                       ERR("Invalid probe description %s", s_hex);
                        ret = CMD_ERROR;
                        goto end;
                }
@@ -290,6 +285,65 @@ 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)
+{
+       int ret;
+
+       /* Check if the symbol field is an hex address. */
+       ret = sscanf(symbol, "0x%*x");
+       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, "%*u");
+       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%*x");
+       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, "%*[^+]+%*u");
+       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
@@ -313,6 +367,13 @@ static int parse_userspace_probe_opts(struct lttng_event *ev, char *opt)
                goto end;
        }
 
+       switch (ev->type) {
+       case LTTNG_EVENT_USERSPACE_PROBE:
+               break;
+       default:
+               assert(0);
+       }
+
        /*
         * userspace probe fields are separated by ':'.
         */
@@ -369,7 +430,7 @@ static int parse_userspace_probe_opts(struct lttng_event *ev, char *opt)
                lookup_method =
                        lttng_userspace_probe_location_lookup_method_tracepoint_sdt_create();
                if (!lookup_method) {
-                       WARN("Failed to create ELF lookup method");
+                       WARN("Failed to create SDT lookup method");
                        ret = CMD_ERROR;
                        goto end_string;
                }
@@ -382,53 +443,63 @@ static int parse_userspace_probe_opts(struct lttng_event *ev, char *opt)
        /* strutils_unescape_string allocates a new char *. */
        unescaped_target_path = strutils_unescape_string(target_path, 0);
        if (!unescaped_target_path) {
-               ret = -LTTNG_ERR_INVALID;
-               goto end_string;
+               ret = CMD_ERROR;
+               goto end_destroy_lookup_method;
        }
 
        /*
         * If there is not forward slash in the path. Walk the $PATH else
         * expand.
         */
-       if (strchr(target_path, '/') == NULL) {
+       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_unescaped_string;
+                       goto end_destroy_lookup_method;
                }
-               ret = walk_command_search_path(target_path, real_target_path);
+               ret = walk_command_search_path(unescaped_target_path, real_target_path);
                if (ret) {
                        ERR("Binary not found.");
                        ret = CMD_ERROR;
-                       goto end_free_path;
+                       goto end_destroy_lookup_method;
                }
        } else {
                /*
                 * Expand references to `/./` and `/../`. This function does not check
-                * if the file exists.
+                * if the file exists. This call returns an allocated buffer on
+                * success.
                 */
-               real_target_path = utils_expand_path_keep_symlink(target_path);
+               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_free_path;
+                       goto end_destroy_lookup_method;
                }
 
                /*
-                * Check if the file exists using access(2). If it does not, walk the
-                * $PATH.
+                * Check if the file exists using access(2), If it does not,
+                * return an error.
                 */
                ret = access(real_target_path, F_OK);
                if (ret) {
+                       ERR("Cannot find binary at path: %s.", real_target_path);
                        ret = CMD_ERROR;
-                       goto end_free_path;
+                       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) {
@@ -468,32 +539,24 @@ static int parse_userspace_probe_opts(struct lttng_event *ev, char *opt)
                break;
        default:
                ret = CMD_ERROR;
-               goto end_string;
+               goto end_destroy_lookup_method;
        }
 
-       switch (ev->type) {
-       case LTTNG_EVENT_USERSPACE_PROBE:
-               break;
-       default:
-               assert(0);
-       }
-
-       goto end;
+       /* 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_free_path:
+end_string:
+       strutils_free_null_terminated_array_of_strings(tokens);
        /*
-        * Free path that was allocated by the call to realpath() or when walking
-        * the PATH.
+        * Freeing both char * here makes the error handling simplier. free()
+        * performs not action if the pointer is NULL.
         */
        free(real_target_path);
-end_unescaped_string:
        free(unescaped_target_path);
-end_string:
-       strutils_free_null_terminated_array_of_strings(tokens);
 end:
        return ret;
 }
@@ -737,7 +800,7 @@ char *print_exclusions(char **names)
 {
        int length = 0;
        int i;
-       const char *preamble = " excluding ";
+       const char preamble[] = " excluding ";
        char *ret;
        int count = names ? strutils_array_of_strings_len(names) : 0;
 
@@ -750,9 +813,8 @@ char *print_exclusions(char **names)
                length += strlen(names[i]) + 4;
        }
 
-       /* add length of preamble + one for NUL - one for last (missing) comma */
-       length += strlen(preamble);
-       ret = zmalloc(length + 1);
+       length += sizeof(preamble);
+       ret = zmalloc(length);
        if (!ret) {
                return NULL;
        }
@@ -965,6 +1027,30 @@ 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);
@@ -1272,8 +1358,19 @@ static int enable_events(char *session_name)
                        case LTTNG_EVENT_USERSPACE_PROBE:
                                ret = parse_userspace_probe_opts(ev, opt_userspace_probe);
                                if (ret) {
-                                       ERR("Unable to parse userspace probe options");
-                                       ret = CMD_ERROR;
+                                       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;
@@ -1675,7 +1772,9 @@ int cmd_enable_events(int argc, const char **argv)
        }
 
        ret = print_missing_or_multiple_domains(
-               opt_kernel + opt_userspace + opt_jul + opt_log4j + opt_python);
+                       opt_kernel + opt_userspace + opt_jul + opt_log4j +
+                                       opt_python,
+                       true);
        if (ret) {
                ret = CMD_ERROR;
                goto end;
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