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