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util-linux/include/c.h

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/*
* Fundamental C definitions.
*
* No copyright is claimed. This code is in the public domain; do with
* it what you wish.
*/
#ifndef UTIL_LINUX_C_H
#define UTIL_LINUX_C_H
#include <limits.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <unistd.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <sys/types.h>
#include <grp.h>
#include <assert.h>
#ifdef HAVE_ERR_H
# include <err.h>
#endif
#ifdef HAVE_SYS_SYSMACROS_H
# include <sys/sysmacros.h> /* for major, minor */
#endif
#ifndef LOGIN_NAME_MAX
# define LOGIN_NAME_MAX 256
#endif
#ifndef NAME_MAX
# define NAME_MAX PATH_MAX
#endif
/*
* __GNUC_PREREQ is deprecated in favour of __has_attribute() and
* __has_feature(). The __has macros are supported by clang and gcc>=5.
*/
#ifndef __GNUC_PREREQ
# if defined __GNUC__ && defined __GNUC_MINOR__
# define __GNUC_PREREQ(maj, min) \
((__GNUC__ << 16) + __GNUC_MINOR__ >= ((maj) << 16) + (min))
# else
# define __GNUC_PREREQ(maj, min) 0
# endif
#endif
#ifdef __GNUC__
/* &a[0] degrades to a pointer: a different type from an array */
# define __must_be_array(a) \
UL_BUILD_BUG_ON_ZERO(__builtin_types_compatible_p(__typeof__(a), __typeof__(&a[0])))
# define ignore_result(x) __extension__ ({ \
__typeof__(x) __dummy __attribute__((__unused__)) = (x); (void) __dummy; \
})
#else /* !__GNUC__ */
# define __must_be_array(a) 0
# define __attribute__(_arg_)
# define ignore_result(x) ((void) (x))
#endif /* !__GNUC__ */
/* "restrict" keyword fallback */
#if __STDC__ != 1
# define restrict __restrict /* use implementation __ format */
#else
# ifndef __STDC_VERSION__
# define restrict __restrict /* use implementation __ format */
# else
# if __STDC_VERSION__ < 199901L
# define restrict __restrict /* use implementation __ format */
# endif
# endif
#endif
/*
* It evaluates to 1 if the attribute/feature is supported by the current
* compilation target. Fallback for old compilers.
*/
#ifndef __has_attribute
#define __has_attribute(x) 0
#endif
#ifndef __has_feature
#define __has_feature(x) 0
#endif
/*
* Function attributes
*/
#ifndef __ul_alloc_size
# if (__has_attribute(alloc_size) && __has_attribute(warn_unused_result)) || __GNUC_PREREQ (4, 3)
# define __ul_alloc_size(s) __attribute__((alloc_size(s), warn_unused_result))
# else
# define __ul_alloc_size(s)
# endif
#endif
#ifndef __ul_calloc_size
# if (__has_attribute(alloc_size) && __has_attribute(warn_unused_result)) || __GNUC_PREREQ (4, 3)
# define __ul_calloc_size(n, s) __attribute__((alloc_size(n, s), warn_unused_result))
# else
# define __ul_calloc_size(n, s)
# endif
#endif
#if __has_attribute(returns_nonnull) || __GNUC_PREREQ (4, 9)
# define __ul_returns_nonnull __attribute__((returns_nonnull))
#else
# define __ul_returns_nonnull
#endif
/*
* Force a compilation error if condition is true, but also produce a
* result (of value 0 and type size_t), so the expression can be used
* e.g. in a structure initializer (or wherever else comma expressions
* aren't permitted).
*/
#define UL_BUILD_BUG_ON_ZERO(e) __extension__ (sizeof(struct { int:-!!(e); }))
#define BUILD_BUG_ON_NULL(e) ((void *)sizeof(struct { int:-!!(e); }))
#ifndef ARRAY_SIZE
# define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + __must_be_array(arr))
#endif
#ifndef PATH_MAX
# define PATH_MAX 4096
#endif
#ifndef TRUE
# define TRUE 1
#endif
#ifndef FALSE
# define FALSE 0
#endif
#ifndef min
# define min(x, y) __extension__ ({ \
__typeof__(x) _min1 = (x); \
__typeof__(y) _min2 = (y); \
(void) (&_min1 == &_min2); \
_min1 < _min2 ? _min1 : _min2; })
#endif
#ifndef max
# define max(x, y) __extension__ ({ \
__typeof__(x) _max1 = (x); \
__typeof__(y) _max2 = (y); \
(void) (&_max1 == &_max2); \
_max1 > _max2 ? _max1 : _max2; })
#endif
#ifndef abs_diff
# define abs_diff(x, y) __extension__ ({ \
__typeof__(x) _a = (x); \
__typeof__(y) _b = (y); \
(void) (&_a == &_b); \
_a > _b ? _a - _b : _b - _a; })
#endif
#ifndef cmp_numbers
# define cmp_numbers(x, y) __extension__ ({ \
__typeof__(x) _a = (x); \
__typeof__(y) _b = (y); \
(void) (&_a == &_b); \
_a == _b ? 0 : _a > _b ? 1 : -1; })
#endif
#ifndef cmp_timespec
# define cmp_timespec(a, b, CMP) \
(((a)->tv_sec == (b)->tv_sec) \
? ((a)->tv_nsec CMP (b)->tv_nsec) \
: ((a)->tv_sec CMP (b)->tv_sec))
#endif
#ifndef cmp_stat_mtime
# ifdef HAVE_STRUCT_STAT_ST_MTIM_TV_NSEC
# define cmp_stat_mtime(_a, _b, CMP) cmp_timespec(&(_a)->st_mtim, &(_b)->st_mtim, CMP)
# else
# define cmp_stat_mtime(_a, _b, CMP) ((_a)->st_mtime CMP (_b)->st_mtime)
# endif
#endif
#ifndef offsetof
#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
#endif
/*
* container_of - cast a member of a structure out to the containing structure
* @ptr: the pointer to the member.
* @type: the type of the container struct this is embedded in.
* @member: the name of the member within the struct.
*/
#ifndef container_of
#define container_of(ptr, type, member) __extension__ ({ \
const __typeof__( ((type *)0)->member ) *__mptr = (ptr); \
(type *)( (char *)__mptr - offsetof(type,member) );})
#endif
#ifndef HAVE_PROGRAM_INVOCATION_SHORT_NAME
# ifdef HAVE___PROGNAME
extern char *__progname;
# define program_invocation_short_name __progname
# else
# ifdef HAVE_GETEXECNAME
# define program_invocation_short_name \
prog_inv_sh_nm_from_file(getexecname(), 0)
# else
# define program_invocation_short_name \
prog_inv_sh_nm_from_file(__FILE__, 1)
# endif
static char prog_inv_sh_nm_buf[256];
static inline char *
prog_inv_sh_nm_from_file(char *f, char stripext)
{
char *t;
if ((t = strrchr(f, '/')) != NULL)
t++;
else
t = f;
strncpy(prog_inv_sh_nm_buf, t, sizeof(prog_inv_sh_nm_buf) - 1);
prog_inv_sh_nm_buf[sizeof(prog_inv_sh_nm_buf) - 1] = '\0';
if (stripext && (t = strrchr(prog_inv_sh_nm_buf, '.')) != NULL)
*t = '\0';
return prog_inv_sh_nm_buf;
}
# endif
#endif
#ifndef HAVE_ERR_H
static inline void __attribute__ ((__format__ (__printf__, 4, 5)))
errmsg(char doexit, int excode, char adderr, const char *fmt, ...)
{
fprintf(stderr, "%s: ", program_invocation_short_name);
if (fmt != NULL) {
va_list argp;
va_start(argp, fmt);
vfprintf(stderr, fmt, argp);
va_end(argp);
if (adderr)
fprintf(stderr, ": ");
}
if (adderr)
fprintf(stderr, "%m");
fprintf(stderr, "\n");
if (doexit)
exit(excode);
}
#ifndef HAVE_ERR
# define err(E, FMT...) errmsg(1, E, 1, FMT)
#endif
#ifndef HAVE_ERRX
# define errx(E, FMT...) errmsg(1, E, 0, FMT)
#endif
#ifndef HAVE_WARN
# define warn(FMT...) errmsg(0, 0, 1, FMT)
#endif
#ifndef HAVE_WARNX
# define warnx(FMT...) errmsg(0, 0, 0, FMT)
#endif
#endif /* !HAVE_ERR_H */
/* Don't use inline function to avoid '#include "nls.h"' in c.h
*/
#define errtryhelp(eval) __extension__ ({ \
fprintf(stderr, _("Try '%s --help' for more information.\n"), \
program_invocation_short_name); \
exit(eval); \
})
/* After failed execvp() */
#define EX_EXEC_FAILED 126 /* Program located, but not usable. */
#define EX_EXEC_ENOENT 127 /* Could not find program to exec. */
#define errexec(name) err(errno == ENOENT ? EX_EXEC_ENOENT : EX_EXEC_FAILED, \
_("failed to execute %s"), name)
static inline __attribute__((const)) int is_power_of_2(unsigned long num)
{
return (num != 0 && ((num & (num - 1)) == 0));
}
#ifndef HAVE_LOFF_T
typedef int64_t loff_t;
#endif
#if !defined(HAVE_DIRFD) && (!defined(HAVE_DECL_DIRFD) || HAVE_DECL_DIRFD == 0) && defined(HAVE_DIR_DD_FD)
#include <sys/types.h>
#include <dirent.h>
static inline int dirfd(DIR *d)
{
return d->dd_fd;
}
#endif
/*
* Fallback defines for old versions of glibc
*/
#include <fcntl.h>
#ifdef O_CLOEXEC
#define UL_CLOEXECSTR "e"
#else
#define UL_CLOEXECSTR ""
#endif
#ifndef O_CLOEXEC
#define O_CLOEXEC 0
#endif
#ifdef __FreeBSD_kernel__
#ifndef F_DUPFD_CLOEXEC
#define F_DUPFD_CLOEXEC 17 /* Like F_DUPFD, but FD_CLOEXEC is set */
#endif
#endif
#ifndef AI_ADDRCONFIG
#define AI_ADDRCONFIG 0x0020
#endif
#ifndef IUTF8
#define IUTF8 0040000
#endif
/*
* MAXHOSTNAMELEN replacement
*/
static inline size_t get_hostname_max(void)
{
long len = sysconf(_SC_HOST_NAME_MAX);
if (0 < len)
return len;
#ifdef MAXHOSTNAMELEN
return MAXHOSTNAMELEN;
#elif HOST_NAME_MAX
return HOST_NAME_MAX;
#endif
return 64;
}
static inline int drop_permissions(void)
{
errno = 0;
/* drop GID */
if (setgid(getgid()) < 0)
goto fail;
/* drop UID */
if (setuid(getuid()) < 0)
goto fail;
return 0;
fail:
return errno ? -errno : -1;
}
/*
* The usleep function was marked obsolete in POSIX.1-2001 and was removed
* in POSIX.1-2008. It was replaced with nanosleep() that provides more
* advantages (like no interaction with signals and other timer functions).
*/
#include <time.h>
static inline int xusleep(useconds_t usec)
{
#ifdef HAVE_NANOSLEEP
struct timespec waittime = {
.tv_sec = usec / 1000000L,
.tv_nsec = (usec % 1000000L) * 1000
};
return nanosleep(&waittime, NULL);
#elif defined(HAVE_USLEEP)
return usleep(usec);
#else
# error "System with usleep() or nanosleep() required!"
#endif
}
/*
* Constant strings for usage() functions. For more info see
* Documentation/{howto-usage-function.txt,boilerplate.c}
*/
#define USAGE_HEADER _("\nUsage:\n")
#define USAGE_OPTIONS _("\nOptions:\n")
#define USAGE_FUNCTIONS _("\nFunctions:\n")
#define USAGE_COMMANDS _("\nCommands:\n")
#define USAGE_ARGUMENTS _("\nArguments:\n")
#define USAGE_COLUMNS _("\nAvailable output columns:\n")
#define USAGE_SEPARATOR "\n"
#define USAGE_OPTSTR_HELP _("display this help")
#define USAGE_OPTSTR_VERSION _("display version")
#define USAGE_HELP_OPTIONS(marg_dsc) \
"%-" #marg_dsc "s%s\n" \
"%-" #marg_dsc "s%s\n" \
, " -h, --help", USAGE_OPTSTR_HELP \
, " -V, --version", USAGE_OPTSTR_VERSION
#define USAGE_ARG_SEPARATOR "\n"
#define USAGE_ARG_SIZE(_name) \
_(" %s arguments may be followed by the suffixes for\n" \
" GiB, TiB, PiB, EiB, ZiB, and YiB (the \"iB\" is optional)\n"), _name
#define USAGE_MAN_TAIL(_man) _("\nFor more details see %s.\n"), _man
#define UTIL_LINUX_VERSION _("%s from %s\n"), program_invocation_short_name, PACKAGE_STRING
#define print_version(eval) __extension__ ({ \
printf(UTIL_LINUX_VERSION); \
exit(eval); \
})
static inline void print_features(const char **features, const char *prefix)
{
if (features && *features) {
const char **p = features;
while (p && *p) {
if (prefix && p == features)
printf(" (%s ", prefix);
else
fputs(p == features ? " (" : ", ", stdout);
fputs(*p++, stdout);
}
fputc(')', stdout);
}
}
#define UTIL_LINUX_VERSION_NOBREAK _("%s from %s"), program_invocation_short_name, PACKAGE_STRING
#define print_version_with_features(eval, features) __extension__ ({ \
printf(UTIL_LINUX_VERSION_NOBREAK); \
print_features(features, _("features:")); \
fputc('\n', stdout); \
exit(eval); \
})
/*
* seek stuff
*/
#ifndef SEEK_DATA
# define SEEK_DATA 3
#endif
#ifndef SEEK_HOLE
# define SEEK_HOLE 4
#endif
/*
* Macros to convert #define'itions to strings, for example
* #define XYXXY 42
* printf ("%s=%s\n", stringify(XYXXY), stringify_value(XYXXY));
*/
#define stringify_value(s) stringify(s)
#define stringify(s) #s
/* Detect if we're compiled with Address Sanitizer
* - gcc (__SANITIZE_ADDRESS__)
* - clang (__has_feature(address_sanitizer))
*/
#if !defined(HAS_FEATURE_ADDRESS_SANITIZER)
# ifdef __SANITIZE_ADDRESS__
# define HAS_FEATURE_ADDRESS_SANITIZER 1
# elif defined(__has_feature)
# if __has_feature(address_sanitizer)
# define HAS_FEATURE_ADDRESS_SANITIZER 1
# endif
# endif
# if !defined(HAS_FEATURE_ADDRESS_SANITIZER)
# define HAS_FEATURE_ADDRESS_SANITIZER 0
# endif
#endif
/*
* UL_ASAN_BLACKLIST is a macro to tell AddressSanitizer (a compile-time
* instrumentation shipped with Clang and GCC) to not instrument the
* annotated function. Furthermore, it will prevent the compiler from
* inlining the function because inlining currently breaks the blacklisting
* mechanism of AddressSanitizer.
*/
#if __has_feature(address_sanitizer) && __has_attribute(no_sanitize_memory) && __has_attribute(no_sanitize_address)
# define UL_ASAN_BLACKLIST __attribute__((noinline)) __attribute__((no_sanitize_memory)) __attribute__((no_sanitize_address))
#else
# define UL_ASAN_BLACKLIST /* nothing */
#endif
/*
* Note that sysconf(_SC_GETPW_R_SIZE_MAX) returns *initial* suggested size for
* pwd buffer and in some cases it is not large enough. See POSIX and
* getpwnam_r man page for more details.
*/
#define UL_GETPW_BUFSIZ (16 * 1024)
/*
* Darwin or other BSDs may only have MAP_ANON. To get it on Darwin we must
* define _DARWIN_C_SOURCE before including sys/mman.h. We do this in config.h.
*/
#if !defined MAP_ANONYMOUS && defined MAP_ANON
# define MAP_ANONYMOUS (MAP_ANON)
#endif
#endif /* UTIL_LINUX_C_H */