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/****************************************************************************
* bfs *
* Copyright (C) 2016-2021 Tavian Barnes <tavianator@tavianator.com> *
* *
* 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 <fcntl.h>
#include <fnmatch.h>
#include <regex.h>
#include <stdbool.h>
#include <stddef.h>
#include <sys/types.h>
// 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
#ifndef BFS_HAS_MNTENT
# define BFS_HAS_MNTENT BFS_HAS_INCLUDE(<mntent.h>, __GLIBC__)
#endif
#ifndef BFS_HAS_SYS_ACL
# define BFS_HAS_SYS_ACL BFS_HAS_INCLUDE(<sys/acl.h>, true)
#endif
#ifndef BFS_HAS_SYS_CAPABILITY
# define BFS_HAS_SYS_CAPABILITY BFS_HAS_INCLUDE(<sys/capability.h>, __linux__)
#endif
#ifndef BFS_HAS_SYS_EXTATTR
# define BFS_HAS_SYS_EXTATTR BFS_HAS_INCLUDE(<sys/extattr.h>, __FreeBSD__)
#endif
#ifndef BFS_HAS_SYS_MKDEV
# define BFS_HAS_SYS_MKDEV BFS_HAS_INCLUDE(<sys/mkdev.h>, false)
#endif
#ifndef BFS_HAS_SYS_PARAM
# define BFS_HAS_SYS_PARAM BFS_HAS_INCLUDE(<sys/param.h>, true)
#endif
#ifndef BFS_HAS_SYS_SYSMACROS
# define BFS_HAS_SYS_SYSMACROS BFS_HAS_INCLUDE(<sys/sysmacros.h>, __GLIBC__)
#endif
#ifndef BFS_HAS_SYS_XATTR
# define BFS_HAS_SYS_XATTR BFS_HAS_INCLUDE(<sys/xattr.h>, __linux__)
#endif
#ifndef BFS_HAS_UTIL
# define BFS_HAS_UTIL BFS_HAS_INCLUDE(<util.h>, __NetBSD__)
#endif
#if !defined(FNM_CASEFOLD) && defined(FNM_IGNORECASE)
# define FNM_CASEFOLD FNM_IGNORECASE
#endif
#ifndef O_DIRECTORY
# define O_DIRECTORY 0
#endif
/**
* Adds compiler warnings for bad printf()-style function calls, if supported.
*/
#if __GNUC__
# 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]);
/**
* Dynamically allocate a regex error message.
*
* @param err
* The error code to stringify.
* @param regex
* The (partially) compiled regex.
* @return A human-readable description of the error, allocated with malloc().
*/
char *xregerror(int err, const regex_t *regex);
/**
* 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);
#endif // BFS_UTIL_H
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