X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fcommon%2Futils.cpp;fp=src%2Fcommon%2Futils.cpp;h=2ebaa84bb507c44a39715d74e900366f3486c81b;hp=93014627fe5162bf8d49c4813074debe3edf1ca7;hb=4971b7f0243bd3a7a661bcf1cfe95f0f8014b59b;hpb=c46a183e556278a2971dea1e5b87a6b995274bda diff --git a/src/common/utils.cpp b/src/common/utils.cpp index 93014627f..2ebaa84bb 100644 --- a/src/common/utils.cpp +++ b/src/common/utils.cpp @@ -1,6 +1,5 @@ /* * Copyright (C) 2012 David Goulet - * Copyright (C) 2013 Raphaël Beamonte * Copyright (C) 2013 Jérémie Galarneau * * SPDX-License-Identifier: GPL-2.0-only @@ -53,375 +52,6 @@ #define FALLBACK_USER_BUFLEN 16384 #define FALLBACK_GROUP_BUFLEN 16384 -/* - * Return a partial realpath(3) of the path even if the full path does not - * exist. For instance, with /tmp/test1/test2/test3, if test2/ does not exist - * but the /tmp/test1 does, the real path for /tmp/test1 is concatened with - * /test2/test3 then returned. In normal time, realpath(3) fails if the end - * point directory does not exist. - * - * Return a newly-allocated string. - */ -static -char *utils_partial_realpath(const char *path) -{ - char *cut_path = NULL, *try_path = NULL, *try_path_prev = NULL; - const char *next, *prev, *end; - char *resolved_path = NULL; - - /* Safety net */ - if (path == NULL) { - goto error; - } - - /* - * Identify the end of the path, we don't want to treat the - * last char if it is a '/', we will just keep it on the side - * to be added at the end, and return a value coherent with - * the path given as argument - */ - end = path + strlen(path); - if (*(end-1) == '/') { - end--; - } - - /* Initiate the values of the pointers before looping */ - next = path; - prev = next; - /* Only to ensure try_path is not NULL to enter the while */ - try_path = (char *)next; - - /* Resolve the canonical path of the first part of the path */ - while (try_path != NULL && next != end) { - char *try_path_buf = NULL; - - /* - * If there is not any '/' left, we want to try with - * the full path - */ - next = strpbrk(next + 1, "/"); - if (next == NULL) { - next = end; - } - - /* Cut the part we will be trying to resolve */ - cut_path = lttng_strndup(path, next - path); - if (cut_path == NULL) { - PERROR("lttng_strndup"); - goto error; - } - - try_path_buf = (char *) zmalloc(LTTNG_PATH_MAX); - if (!try_path_buf) { - PERROR("zmalloc"); - goto error; - } - - /* Try to resolve this part */ - try_path = realpath((char *) cut_path, try_path_buf); - if (try_path == NULL) { - free(try_path_buf); - /* - * There was an error, we just want to be assured it - * is linked to an unexistent directory, if it's another - * reason, we spawn an error - */ - switch (errno) { - case ENOENT: - /* Ignore the error */ - break; - default: - PERROR("realpath (partial_realpath)"); - goto error; - break; - } - } else { - /* Save the place we are before trying the next step */ - try_path_buf = NULL; - free(try_path_prev); - try_path_prev = try_path; - prev = next; - } - - /* Free the allocated memory */ - free(cut_path); - cut_path = NULL; - } - - /* Allocate memory for the resolved path. */ - resolved_path = (char *) zmalloc(LTTNG_PATH_MAX); - if (resolved_path == NULL) { - PERROR("zmalloc resolved path"); - goto error; - } - - /* - * If we were able to solve at least partially the path, we can concatenate - * what worked and what didn't work - */ - if (try_path_prev != NULL) { - /* If we risk to concatenate two '/', we remove one of them */ - if (try_path_prev[strlen(try_path_prev) - 1] == '/' && prev[0] == '/') { - try_path_prev[strlen(try_path_prev) - 1] = '\0'; - } - - /* - * Duplicate the memory used by prev in case resolved_path and - * path are pointers for the same memory space - */ - cut_path = strdup(prev); - if (cut_path == NULL) { - PERROR("strdup"); - goto error; - } - - /* Concatenate the strings */ - snprintf(resolved_path, LTTNG_PATH_MAX, "%s%s", - try_path_prev, cut_path); - - /* Free the allocated memory */ - free(cut_path); - free(try_path_prev); - cut_path = NULL; - try_path_prev = NULL; - /* - * Else, we just copy the path in our resolved_path to - * return it as is - */ - } else { - strncpy(resolved_path, path, LTTNG_PATH_MAX); - } - - /* Then we return the 'partially' resolved path */ - return resolved_path; - -error: - free(resolved_path); - free(cut_path); - free(try_path); - if (try_path_prev != try_path) { - free(try_path_prev); - } - return NULL; -} - -static -int expand_double_slashes_dot_and_dotdot(char *path) -{ - size_t expanded_path_len, path_len; - const char *curr_char, *path_last_char, *next_slash, *prev_slash; - - path_len = strlen(path); - path_last_char = &path[path_len]; - - if (path_len == 0) { - goto error; - } - - expanded_path_len = 0; - - /* We iterate over the provided path to expand the "//", "../" and "./" */ - for (curr_char = path; curr_char <= path_last_char; curr_char = next_slash + 1) { - /* Find the next forward slash. */ - size_t curr_token_len; - - if (curr_char == path_last_char) { - expanded_path_len++; - break; - } - - next_slash = (const char *) memchr(curr_char, '/', path_last_char - curr_char); - if (next_slash == NULL) { - /* Reached the end of the provided path. */ - next_slash = path_last_char; - } - - /* Compute how long is the previous token. */ - curr_token_len = next_slash - curr_char; - switch(curr_token_len) { - case 0: - /* - * The pointer has not move meaning that curr_char is - * pointing to a slash. It that case there is no token - * to copy, so continue the iteration to find the next - * token - */ - continue; - case 1: - /* - * The pointer moved 1 character. Check if that - * character is a dot ('.'), if it is: omit it, else - * copy the token to the normalized path. - */ - if (curr_char[0] == '.') { - continue; - } - break; - case 2: - /* - * The pointer moved 2 characters. Check if these - * characters are double dots ('..'). If that is the - * case, we need to remove the last token of the - * normalized path. - */ - if (curr_char[0] == '.' && curr_char[1] == '.') { - /* - * Find the previous path component by - * using the memrchr function to find the - * previous forward slash and substract that - * len to the resulting path. - */ - prev_slash = (const char *) lttng_memrchr(path, '/', expanded_path_len); - /* - * If prev_slash is NULL, we reached the - * beginning of the path. We can't go back any - * further. - */ - if (prev_slash != NULL) { - expanded_path_len = prev_slash - path; - } - continue; - } - break; - default: - break; - } - - /* - * Copy the current token which is neither a '.' nor a '..'. - */ - path[expanded_path_len++] = '/'; - memmove(&path[expanded_path_len], curr_char, curr_token_len); - expanded_path_len += curr_token_len; - } - - if (expanded_path_len == 0) { - path[expanded_path_len++] = '/'; - } - - path[expanded_path_len] = '\0'; - return 0; -error: - return -1; -} - -/* - * Make a full resolution of the given path even if it doesn't exist. - * This function uses the utils_partial_realpath function to resolve - * symlinks and relatives paths at the start of the string, and - * implements functionnalities to resolve the './' and '../' strings - * in the middle of a path. This function is only necessary because - * realpath(3) does not accept to resolve unexistent paths. - * The returned string was allocated in the function, it is thus of - * the responsibility of the caller to free this memory. - */ -static -char *_utils_expand_path(const char *path, bool keep_symlink) -{ - int ret; - char *absolute_path = NULL; - char *last_token; - bool is_dot, is_dotdot; - - /* Safety net */ - if (path == NULL) { - goto error; - } - - /* Allocate memory for the absolute_path */ - absolute_path = (char *) zmalloc(LTTNG_PATH_MAX); - if (absolute_path == NULL) { - PERROR("zmalloc expand path"); - goto error; - } - - if (path[0] == '/') { - ret = lttng_strncpy(absolute_path, path, LTTNG_PATH_MAX); - if (ret) { - ERR("Path exceeds maximal size of %i bytes", LTTNG_PATH_MAX); - goto error; - } - } else { - /* - * This is a relative path. We need to get the present working - * directory and start the path walk from there. - */ - char current_working_dir[LTTNG_PATH_MAX]; - char *cwd_ret; - - cwd_ret = getcwd(current_working_dir, sizeof(current_working_dir)); - if (!cwd_ret) { - goto error; - } - /* - * Get the number of character in the CWD and allocate an array - * to can hold it and the path provided by the caller. - */ - ret = snprintf(absolute_path, LTTNG_PATH_MAX, "%s/%s", - current_working_dir, path); - if (ret >= LTTNG_PATH_MAX) { - ERR("Concatenating current working directory %s and path %s exceeds maximal size of %i bytes", - current_working_dir, path, LTTNG_PATH_MAX); - goto error; - } - } - - if (keep_symlink) { - /* Resolve partially our path */ - char *new_absolute_path = utils_partial_realpath(absolute_path); - if (!new_absolute_path) { - goto error; - } - - free(absolute_path); - absolute_path = new_absolute_path; - } - - ret = expand_double_slashes_dot_and_dotdot(absolute_path); - if (ret) { - goto error; - } - - /* Identify the last token */ - last_token = strrchr(absolute_path, '/'); - - /* Verify that this token is not a relative path */ - is_dotdot = (strcmp(last_token, "/..") == 0); - is_dot = (strcmp(last_token, "/.") == 0); - - /* If it is, take action */ - if (is_dot || is_dotdot) { - /* For both, remove this token */ - *last_token = '\0'; - - /* If it was a reference to parent directory, go back one more time */ - if (is_dotdot) { - last_token = strrchr(absolute_path, '/'); - - /* If there was only one level left, we keep the first '/' */ - if (last_token == absolute_path) { - last_token++; - } - - *last_token = '\0'; - } - } - - return absolute_path; - -error: - free(absolute_path); - return NULL; -} -char *utils_expand_path(const char *path) -{ - return _utils_expand_path(path, true); -} - -char *utils_expand_path_keep_symlink(const char *path) -{ - return _utils_expand_path(path, false); -} /* * Create a pipe in dst. */