/**************************************************************************** * bfs * * Copyright (C) 2016-2022 Tavian Barnes * * * * Permission to use, copy, modify, and/or distribute this software for any * * purpose with or without fee is hereby granted. * * * * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES * * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF * * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR * * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES * * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN * * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF * * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. * ****************************************************************************/ /** * Assorted utilities that don't belong anywhere else. */ #ifndef BFS_UTIL_H #define BFS_UTIL_H #include #include #include #include #include #include // Some portability concerns #ifdef __has_feature # define BFS_HAS_FEATURE(feature, fallback) __has_feature(feature) #else # define BFS_HAS_FEATURE(feature, fallback) fallback #endif #ifdef __has_include # define BFS_HAS_INCLUDE(header, fallback) __has_include(header) #else # define BFS_HAS_INCLUDE(header, fallback) fallback #endif #ifdef __has_c_attribute # define BFS_HAS_C_ATTRIBUTE(attr) __has_c_attribute(attr) #else # define BFS_HAS_C_ATTRIBUTE(attr) false #endif #if __GNUC__ && defined(__has_attribute) # define BFS_HAS_GNU_ATTRIBUTE(attr) __has_attribute(attr) #else # define BFS_HAS_GNU_ATTRIBUTE(attr) false #endif #ifndef BFS_HAS_MNTENT # define BFS_HAS_MNTENT BFS_HAS_INCLUDE(, __GLIBC__) #endif #ifndef BFS_HAS_SYS_ACL # define BFS_HAS_SYS_ACL BFS_HAS_INCLUDE(, true) #endif #ifndef BFS_HAS_SYS_CAPABILITY # define BFS_HAS_SYS_CAPABILITY BFS_HAS_INCLUDE(, __linux__) #endif #ifndef BFS_HAS_SYS_EXTATTR # define BFS_HAS_SYS_EXTATTR BFS_HAS_INCLUDE(, __FreeBSD__) #endif #ifndef BFS_HAS_SYS_MKDEV # define BFS_HAS_SYS_MKDEV BFS_HAS_INCLUDE(, false) #endif #ifndef BFS_HAS_SYS_PARAM # define BFS_HAS_SYS_PARAM BFS_HAS_INCLUDE(, true) #endif #ifndef BFS_HAS_SYS_SYSMACROS # define BFS_HAS_SYS_SYSMACROS BFS_HAS_INCLUDE(, __GLIBC__) #endif #ifndef BFS_HAS_SYS_XATTR # define BFS_HAS_SYS_XATTR BFS_HAS_INCLUDE(, __linux__) #endif #ifndef BFS_HAS_UTIL # define BFS_HAS_UTIL BFS_HAS_INCLUDE(, __NetBSD__) #endif #if !defined(FNM_CASEFOLD) && defined(FNM_IGNORECASE) # define FNM_CASEFOLD FNM_IGNORECASE #endif #ifndef O_DIRECTORY # define O_DIRECTORY 0 #endif #if BFS_HAS_C_ATTRIBUTE(fallthrough) # define BFS_FALLTHROUGH [[fallthrough]] #elif BFS_HAS_GNU_ATTRIBUTE(fallthrough) # define BFS_FALLTHROUGH __attribute__((fallthrough)) #else # define BFS_FALLTHROUGH ((void)0) #endif /** * Adds compiler warnings for bad printf()-style function calls, if supported. */ #if BFS_HAS_GNU_ATTRIBUTE(format) # define BFS_FORMATTER(fmt, args) __attribute__((format(printf, fmt, args))) #else # define BFS_FORMATTER(fmt, args) #endif // Lower bound on BFS_FLEX_SIZEOF() #define BFS_FLEX_LB(type, member, length) (offsetof(type, member) + sizeof(((type *)NULL)->member[0]) * (length)) // Maximum macro for BFS_FLEX_SIZE() #define BFS_FLEX_MAX(a, b) ((a) > (b) ? (a) : (b)) /** * Computes the size of a struct containing a flexible array member of the given * length. * * @param type * The type of the struct containing the flexible array. * @param member * The name of the flexible array member. * @param length * The length of the flexible array. */ #define BFS_FLEX_SIZEOF(type, member, length) \ (sizeof(type) <= BFS_FLEX_LB(type, member, 0) \ ? BFS_FLEX_LB(type, member, length) \ : BFS_FLEX_MAX(sizeof(type), BFS_FLEX_LB(type, member, length))) /** * readlinkat() wrapper that dynamically allocates the result. * * @param fd * The base directory descriptor. * @param path * The path to the link, relative to fd. * @param size * An estimate for the size of the link name (pass 0 if unknown). * @return The target of the link, allocated with malloc(), or NULL on failure. */ char *xreadlinkat(int fd, const char *path, size_t size); /** * Like dup(), but set the FD_CLOEXEC flag. * * @param fd * The file descriptor to duplicate. * @return A duplicated file descriptor, or -1 on failure. */ int dup_cloexec(int fd); /** * Like pipe(), but set the FD_CLOEXEC flag. * * @param pipefd * The array to hold the two file descriptors. * @return 0 on success, -1 on failure. */ int pipe_cloexec(int pipefd[2]); /** * Format a mode like ls -l (e.g. -rw-r--r--). * * @param mode * The mode to format. * @param str * The string to hold the formatted mode. */ void xstrmode(mode_t mode, char str[11]); /** * basename() variant that doesn't modify the input. * * @param path * The path in question. * @return A pointer into path at the base name offset. */ const char *xbasename(const char *path); /** * Wrapper for faccessat() that handles some portability issues. */ int xfaccessat(int fd, const char *path, int amode); /** * Portability wrapper for strtofflags(). * * @param str * The string to parse. The pointee will be advanced to the first * invalid position on error. * @param set * The flags that are set in the string. * @param clear * The flags that are cleared in the string. * @return * 0 on success, -1 on failure. */ int xstrtofflags(const char **str, unsigned long long *set, unsigned long long *clear); /** * Return whether an error code is due to a path not existing. */ bool is_nonexistence_error(int error); /** * Process a yes/no prompt. * * @return 1 for yes, 0 for no, and -1 for unknown. */ int ynprompt(void); /** * Portable version of makedev(). */ dev_t bfs_makedev(int ma, int mi); /** * Portable version of major(). */ int bfs_major(dev_t dev); /** * Portable version of minor(). */ int bfs_minor(dev_t dev); /** * A safe version of read() that handles interrupted system calls and partial * reads. * * @return * The number of bytes read. A value != nbytes indicates an error * (errno != 0) or end of file (errno == 0). */ size_t xread(int fd, void *buf, size_t nbytes); /** * A safe version of write() that handles interrupted system calls and partial * writes. * * @return The number of bytes written. A value != nbytes indicates an error. */ size_t xwrite(int fd, const void *buf, size_t nbytes); /** * Wrapper for confstr() that allocates with malloc(). * * @param name * The ID of the confstr to look up. * @return * The value of the confstr, or NULL on failure. */ char *xconfstr(int name); /** * Convenience wrapper for getdelim(). * * @param file * The file to read. * @param delim * The delimiter character to split on. * @return * The read chunk (without the delimiter), allocated with malloc(). * NULL is returned on error (errno != 0) or end of file (errno == 0). */ char *xgetdelim(FILE *file, char delim); /** * fopen() variant that takes open() style flags. * * @param path * The path to open. * @param flags * Flags to pass to open(). */ FILE *xfopen(const char *path, int flags); /** * close() wrapper that asserts the file descriptor is valid. * * @param fd * The file descriptor to close. * @return * 0 on success, or -1 on error. */ int xclose(int fd); /** * close() variant that preserves errno. * * @param fd * The file descriptor to close. */ void close_quietly(int fd); #endif // BFS_UTIL_H