/* Authors: John Dennis Copyright (C) 2009 Red Hat This program is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version. 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 Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this program. If not, see . */ #ifndef PATH_UTILS_H #define PATH_UTILS_H /*****************************************************************************/ /******************************** Documentation ******************************/ /*****************************************************************************/ /** @mainpage Pathname manipulation utilities * * This library contains a set of utilities designed to extract info from * and manipulate path names. * */ /*****************************************************************************/ /******************************* Include Files *******************************/ /*****************************************************************************/ #include #include #include #include /*****************************************************************************/ /*********************************** Defines *********************************/ /*****************************************************************************/ /** * @defgroup constants Constants * @{ */ #ifndef _ #define _(String) gettext(String) #endif /** * @brief SUCCESS (=0) is returned by all functions in the path_utils * library on success. */ #ifndef SUCCESS #define SUCCESS 0 #endif /** * @} */ /** * @defgroup errors Error codes and macros * @{ */ #define PATH_UTILS_ERROR_BASE -3000 #define PATH_UTILS_ERROR_LIMIT (PATH_UTILS_ERROR_BASE+20) /** * @brief You can use this macro to check if an error code is one of * the internal path_utils codes. */ #define IS_PATH_UTILS_ERROR(error) (((error) >= PATH_UTILS_ERROR_BASE) && ((error) < PATH_UTILS_ERROR_LIMIT)) /** @brief A path cannot be normalized due to too many parent links * * Returned when a relative path contains too many parent (\c "..") links. * Please see the documentation of \c normalize_path() for full explanation. */ #define PATH_UTILS_ERROR_NOT_FULLY_NORMALIZED (PATH_UTILS_ERROR_BASE + 1) /** * @} */ /*****************************************************************************/ /******************************* Type Definitions ****************************/ /*****************************************************************************/ /*****************************************************************************/ /************************* External Global Variables ***********************/ /*****************************************************************************/ /*****************************************************************************/ /**************************** Exported Functions ***************************/ /*****************************************************************************/ /** * @defgroup functions Functions * @{ */ /** @brief Given an error code return the string description. * * @param[in] error The error code * * @return Error string. If error code is not recognized \c NULL is returned. */ const char *path_utils_error_string(int error); /** @brief Get the basename component of a path * * Given a path, copy the basename component (in the usual case, the part * following the final "/") into the buffer \c base_name * whose length is \c base_name_size. If the path does not contain a slash, * \c get_basename() returns a copy of path. * * @param[out] base_name The basename component * @param[in] base_name_size The size of the base_name buffer * @param[in] path The full path to parse * * @return \c SUCCESS if successful, non-zero error code otherwise. * Possible errors: * \li \c ENOBUFS if the buffer space is too small * \li \c EINVAL The path was a NULL pointer */ int get_basename(char *base_name, size_t base_name_size, const char *path); /** @brief Copy the directory components of a path * * Given a path, copy the directory components (in the usual case, the path * up to, but not including the final "/") into the buffer \c dir_path whose * length is \c dir_path_size. If the path does not contain a slash, * \c get_dirname() returns the current working directory. * * @param[out] dir_path The directory component * @param[in] dir_path_size The size of the dir_path buffer * @param[in] path The full path to parse * * @return \c SUCCESS if successful, non-zero error code otherwise. * Possible errors: * \li \c ENOBUFS If the buffer space is too small * \li \c EACCES Permission to read or search a component of the filename was denied. * \li \c ENAMETOOLONG The size of the null-terminated pathname exceeds PATH_MAX bytes. * \li \c ENOENT The current working directory has been unlinked. * \li \c EINVAL The path was a NULL pointer */ int get_dirname(char *dir_path, size_t dir_path_size, const char *path); /** @brief Get the basaname and directory components of a path * * Given a path, copy the directory components into the buffer \c dir_path whose * length is \c dir_path_size and copy the basename component into the buffer * \c base_name whose length is \c base_name_size. * * @param[out] base_name The basename component * @param[in] base_name_size The size of the base_name buffer * @param[out] dir_path The directory component * @param[in] dir_path_size The size of the dir_path buffer * @param[in] path The full path to parse * * @return \c SUCCESS if successful, non-zero error code otherwise. * Possible errors: * \li \c ENOBUFS If the buffer space is too small * \li \c EACCES Permission to read or search a component of the filename was denied. * \li \c ENAMETOOLONG The size of the null-terminated pathname exceeds PATH_MAX bytes. * \li \c ENOENT The current working directory has been unlinked. * \li \c EINVAL The path was a NULL pointer */ int get_directory_and_base_name(char *dir_path, size_t dir_path_size, char *base_name, size_t base_name_size, const char *path); /** @brief Tell if path is absolute or relative * * @param[in] path The path to check * * @return \c true if the path is absolute, \c false otherwise. */ bool is_absolute_path(const char *path); /** @brief Concatenate two components of a path * * Given two paths, \c head & \c tail, copy their concatenation into the * buffer \c path whose length is \c path_size. * * @param[out] path The full path * @param[in] path_size The size of the path buffer * @param[in] head The first component of the path * @param[in] tail The second component of the path * * @return \c SUCCESS if successful, non-zero error code otherwise. * \li \c ENOBUFS If the buffer space is too small */ int path_concat(char *path, size_t path_size, const char *head, const char *tail); /** @brief Convert a path into absolute * * Given a path make it absolute storing the absolute path in into the buffer * \c absolute_path whose length is \c absolute_path_size. * * Returns \c SUCCESS if successful, non-zero error code otherwise. Possible errors: * \li \c ENOBUFS If the buffer space is too small * \li \c ENOMEM If user memory cannot be mapped * \li \c ENOENT If directory does not exist (i.e. it has been deleted) * \li \c EFAULT If memory access violation occurs while copying * \li \c EINVAL The path was a NULL pointer */ int make_path_absolute(char *absolute_path, size_t absolute_path_size, const char *path); /** @brief Split a file system path into individual components. * * Split a file system path into individual components. Return a pointer to an * array of char pointers, each array entry is a pointer to a copy of the * component. As a special case if the path begins with / then the first * component is "/" so the caller can identify the pah as absolute with the * first component being the root. The last entry in the array is \c NULL serving * as a termination sentinel. An optional integer count parameter can be * provided, which if non-NULL will have the number of components written into * it. Thus the caller can iterate on the array until it sees a \c NULL pointer or * iterate count times indexing the array. * * The caller is responsible for calling \c free() on the returned array. This * frees both the array of component pointers and the copies of each component * in one operation because the copy of each component is stored in the same * allocation block. * * The original path parameter is not modified. * * In the event of an error \c NULL is returned and count (if specified) will be -1. * * Examples: * * \code * char **components, **component; * int i; * * components = split_path(path, NULL); * for (component = components; *component; component++) * printf("\"%s\" ", *component); * free(components); * \endcode * * -OR- * * \code * components = split_path(path, &count); * for (i = 0; i < count; i++) * printf("\"%s\" ", components[i]); * free(components); * \endcode * * @param[in] path The original path * @param[out] count The number of components the path was split into * * @return An array of char pointers, each array entry is a pointer to a * copy of the component or NULL on error. */ char **split_path(const char *path, int *count); /** @brief Normalizes a path * * Normalizes a path copying the resulting normalized path into the buffer * \c normalized_path whose length is \c normalized_size. * * A path is normalized when: * \li only 1 slash separates all path components * \li there are no \c . path components (except if \c . is the only component) * \li there are no \c .. path components * * The input path may either be an absolute path or a path fragment. * * As a special case if the input path is \c NULL, the empty string \c "", * or \c "." the returned normalized path will be \c ".". * * \c ".." path components point to the parent directory which effectively * means poping the parent off the path. But what happens when there are * more \c ".." path components than ancestors in the path? The answer depends * on whether the path is an absolute path or a path fragment. If the path is * absolute then the extra \c ".." components which would move above the root * (/) are simply ignored. This effectively limits the path to the root. * However if the path is not absolute, rather it is a path fragment, and * there are more \c ".." components than ancestors which can be "popped off" * then as many \c ".." components will be popped off the fragement as * possible without changing the meaning of the path fragment. In this case * some extra \c ".." components will be left in the path and the function * will return the error \c ERROR_COULD_NOT_NORMALIZE_PATH_FULLY. However the * function will still normalize as much of the path fragment as is possible. * The behavior of \c ".." components when the input path is a fragment is * adopted because after normalizing a path fragment then the normalized path * fragment if made absolute should reference the same file system name as if * the unnormalized fragment were made absolute. Note this also means * \c ERROR_COULD_NOT_NORMALIZE_PATH_FULLY will never be returned if the input * path is absolute. * * @returns \c SUCCESS if successful, non-zero error code otherwise. Possible * errors: * \li \c ENOBUFS If the buffer space is too small * \li \c ERROR_COULD_NOT_NORMALIZE_PATH_FULLY If not all \c ".." path components could be removed */ int normalize_path(char *normalized_path, size_t normalized_path_size, const char *path); /** @brief Find the common prefix between two paths * * Finds the common prefix between two paths, returns the common prefix and * optionally the count of how many path components were common between the * two paths (if \c common_count is non-NULL). Please note that for absolute * paths, the \c "/" root prefix is treated as a common components, so the * paths \c "/usr/lib" and \c "/usr/share" would have two common components - * \c "/" and \c "/usr". * * Contrary to some other implementations, \c common_path_prefix() works on * path components, not characters, which guarantees at least some level of * sanity of the returned prefixes (for example, the common prefix of * \c "/usr/share" and \c "/usr/src" would be \c "/usr") * * @returns \c SUCCESS if successful, non-zero error code otherwise. * Possible errors: * \li \c ENOBUFS if the buffer space is too small */ int common_path_prefix(char *common_path, size_t common_path_size, int *common_count, const char *path1, const char *path2); /** @brief Make the input path absolute if it's not already, then normalize it. * * @returns \c SUCCESS if successful, non-zero error code otherwise. * Possible errors: * \li \c ENOBUFS if the buffer space is too small */ int make_normalized_absolute_path(char *result_path, size_t result_path_size, const char *path); /** * Find the first path component which is an existing directory by walking from * the tail of the path to it's head, return the path of the existing directory. * * If the pathname is relative and does not contain a directory, the current * directory is returned as parent. * * @returns \c SUCCESS if successful, non-zero error code otherwise. * Possible errors: * \li \c ENOBUFS if the buffer space is too small * \li \c EACCES Search permission is denied for one of the directories. * \li \c ELOOP Too many symbolic links encountered while traversing the path. * \li \c ENAMETOOLONG File name too long. * \li \c ENOMEM Out of memory (i.e., kernel memory). */ int find_existing_directory_ancestor(char *ancestor, size_t ancestor_size, const char *path); /** @brief callback for the \c directory_list() function * * Please see the description of \c directory_list() to see more * details about this callback * * @param[in] directory Directory name of the visited path * @param[in] base_name Base name of the visited path * @param[in] path Full name of the visited path * @param[in] info Info about the visited directory * @param[in] user_data Callback data passed by caller * * @returns if \c false, do not recursively descend into the directory, * descend if \c true */ typedef bool (*directory_list_callback_t)(const char *directory, const char *base_name, const char *path, struct stat *info, void *user_data); /** @brief Walk a directory. * * Walk a directory. If \c recursive is \c true child directories will be * descended into. The supplied callback is invoked for each entry in the * directory. * * The callback is provided with the directory name, basename, the full * pathname (i.e. directory name + basename) a stat structure for the path * item and a pointer to any user supplied data specified in the \c user_data * parameter. If the callback returns \c false for a directory the recursive * descent into that directory does not occur thus effectively "pruning" * the tree. * * @param[in] path The path to examine * @param[in] recursive Whether to recursively examine entries in the directory * @param[in] callback The callback to invoke for each entry * @param[in] user_data The data to pass into the callback * * @returns SUCCESS if successfull, an error code if not. */ int directory_list(const char *path, bool recursive, directory_list_callback_t callback, void *user_data); /** @brief Tell if one path is ancestor of another * * Test to see if the path passed in the \c ancestor parameter is an ancestor * of the path passed in the path parameter returning true if it is, \c false * otherwise. * * The test is "static" as such it is performed on the string components in * each path. Live symbolic links in the file system are not taken into * consideration. The test operates by splitting each path into it's individual * components and then comparing each component pairwise for string * equality. Both paths mush share a common root component for the test to be * meaningful (e.g. don't attempt to compare an absolute path with a relative * path). * * Example: * \code * is_ancestor_path("/a/b/c" "/a/b/c/d") => true * is_ancestor_path("/a/b/c/d" "/a/b/c/d") => false // equal, not ancestor * is_ancestor_path("/a/x/c" "/a/b/c/d") => false * \endcode * * @returns \c true if \c ancestor is an ancestor of \c path */ bool is_ancestor_path(const char *ancestor, const char *path); /** * @} */ #endif /* PATH_UTILS_H */