From 30e0d2a51026830e5141ce3dd43854819bba910c Mon Sep 17 00:00:00 2001 From: Warner Losh Date: Fri, 20 Jan 2023 16:32:45 -0700 Subject: [PATCH] linux: For better compatibility, provide compatible endian.h Add endian.h. This includes sys/endian.h and then adds extra defines that glibc defines with double underscores for our _{BIG,BYTE,LITTLE,PDP}_ENDIAN macros. We also define __FLOAT_WORD_ORDER to be the same as _BYTE_ENDIAN since FreeBSD doesn't currently define this, and the default with glibc is exactly this for our platforms. Move common parts of endian.h and sys/endian.h into sys/_endian.h to limit namespace pollution from endian.h All this gives us good compatibility with Linux. There may be one or two upstreams that haven't integrated the patches I tried to send up. There are some minor differences: o The extra glibc macros are not defined. These are all controlled with either __ at the start, or only defined when glibc is being built. We also don't define macros that are used internally in glibc that would pollute the namespace. o For complete compatibility, this change must also be paired with providing a glibc-compatible byteswap.h. Sponsored by: Netflix Reviewed by: mhorne, markj, jhb Differential Revision: https://reviews.freebsd.org/D31962 --- include/Makefile | 4 ++-- include/endian.h | 43 +++++++++++++++++++++++++++++++++++++++++++ sys/sys/_endian.h | 36 +++++++++++++++++++++++++++++++++++- sys/sys/endian.h | 42 ++++++------------------------------------ 4 files changed, 86 insertions(+), 39 deletions(-) create mode 100644 include/endian.h diff --git a/include/Makefile b/include/Makefile index 643451367b1b..aa4c115a3931 100644 --- a/include/Makefile +++ b/include/Makefile @@ -14,8 +14,8 @@ SUBDIR+= i386 SUBDIR_PARALLEL= INCS= a.out.h ar.h assert.h bitstring.h complex.h cpio.h _ctype.h ctype.h \ db.h \ - dirent.h dlfcn.h elf.h elf-hints.h err.h fmtmsg.h fnmatch.h fstab.h \ - fts.h ftw.h getopt.h glob.h grp.h \ + dirent.h dlfcn.h elf.h elf-hints.h endian.h err.h fmtmsg.h fnmatch.h \ + fstab.h fts.h ftw.h getopt.h glob.h grp.h \ ieeefp.h ifaddrs.h \ inttypes.h iso646.h kenv.h langinfo.h libgen.h limits.h link.h \ locale.h malloc.h malloc_np.h memory.h monetary.h mpool.h mqueue.h \ diff --git a/include/endian.h b/include/endian.h new file mode 100644 index 000000000000..c7b78217cedd --- /dev/null +++ b/include/endian.h @@ -0,0 +1,43 @@ +/*- + * Copyright (c) 2021 M. Warner Losh + * + * SPDX-License-Identifier: BSD-2-Clause + */ + +/* + * A mostly Linux/glibc-compatible endian.h + */ + +#ifndef _ENDIAN_H_ +#define _ENDIAN_H_ + +/* + * FreeBSD's sys/_endian.h is very close to the interface provided on Linux by + * glibc's endian.h. + */ +#include + +/* + * glibc uses double underscore for these symbols. Define these unconditionally. + * The compiler defines __BYTE_ORDER__ these days, so we don't do anything + * with that since sys/endian.h defines _BYTE_ORDER based on it. + */ +#define __BIG_ENDIAN _BIG_ENDIAN +#define __BYTE_ORDER _BYTE_ORDER +#define __LITTLE_ENDIAN _LITTLE_ENDIAN +#define __PDP_ENDIAN _PDP_ENDIAN + +/* + * FreeBSD's sys/endian.h and machine/endian.h doesn't define a separate + * byte order for floats. Use the host non-float byte order. + */ +#define __FLOAT_WORD_ORDER _BYTE_ORDER + +/* + * We don't define BIG_ENDI, LITTLE_ENDI, HIGH_HALF and LOW_HALF macros that + * glibc's endian.h defines since those appear to be internal to internal to + * glibc. We also don't try to emulate the various helper macros that glibc + * uses to limit namespace visibility. + */ + +#endif /* _ENDIAN_H_ */ diff --git a/sys/sys/_endian.h b/sys/sys/_endian.h index 936962cc729f..72e1a40a8deb 100644 --- a/sys/sys/_endian.h +++ b/sys/sys/_endian.h @@ -32,7 +32,7 @@ #ifndef _SYS__ENDIAN_H_ #define _SYS__ENDIAN_H_ -#ifndef _MACHINE_ENDIAN_H_ +#if !defined(_MACHINE_ENDIAN_H_) && !defined(_ENDIAN_H_) #error "sys/_endian.h should not be included directly" #endif @@ -89,4 +89,38 @@ #define __ntohs(x) ((__uint16_t)(x)) #endif +/* + * Host to big endian, host to little endian, big endian to host, and little + * endian to host byte order functions as detailed in byteorder(9). + */ +#if _BYTE_ORDER == _LITTLE_ENDIAN +#define htobe16(x) __bswap16((x)) +#define htobe32(x) __bswap32((x)) +#define htobe64(x) __bswap64((x)) +#define htole16(x) ((uint16_t)(x)) +#define htole32(x) ((uint32_t)(x)) +#define htole64(x) ((uint64_t)(x)) + +#define be16toh(x) __bswap16((x)) +#define be32toh(x) __bswap32((x)) +#define be64toh(x) __bswap64((x)) +#define le16toh(x) ((uint16_t)(x)) +#define le32toh(x) ((uint32_t)(x)) +#define le64toh(x) ((uint64_t)(x)) +#else /* _BYTE_ORDER != _LITTLE_ENDIAN */ +#define htobe16(x) ((uint16_t)(x)) +#define htobe32(x) ((uint32_t)(x)) +#define htobe64(x) ((uint64_t)(x)) +#define htole16(x) __bswap16((x)) +#define htole32(x) __bswap32((x)) +#define htole64(x) __bswap64((x)) + +#define be16toh(x) ((uint16_t)(x)) +#define be32toh(x) ((uint32_t)(x)) +#define be64toh(x) ((uint64_t)(x)) +#define le16toh(x) __bswap16((x)) +#define le32toh(x) __bswap32((x)) +#define le64toh(x) __bswap64((x)) +#endif /* _BYTE_ORDER == _LITTLE_ENDIAN */ + #endif /* _SYS__ENDIAN_H_ */ diff --git a/sys/sys/endian.h b/sys/sys/endian.h index faac0458ae2c..d91c442e9238 100644 --- a/sys/sys/endian.h +++ b/sys/sys/endian.h @@ -55,6 +55,12 @@ typedef __uint64_t uint64_t; #define _UINT64_T_DECLARED #endif +/* + * Note: While tempting to try to avoid namespace pollution from this file, + * several software packages assume these marcos are defined, even when it + * defines _POSIX_C_SOURCE to request an unpolluted namespace. + */ + /* * General byte order swapping functions. */ @@ -62,42 +68,7 @@ typedef __uint64_t uint64_t; #define bswap32(x) __bswap32(x) #define bswap64(x) __bswap64(x) -/* - * Host to big endian, host to little endian, big endian to host, and little - * endian to host byte order functions as detailed in byteorder(9). - */ -#if _BYTE_ORDER == _LITTLE_ENDIAN -#define htobe16(x) __bswap16((x)) -#define htobe32(x) __bswap32((x)) -#define htobe64(x) __bswap64((x)) -#define htole16(x) ((uint16_t)(x)) -#define htole32(x) ((uint32_t)(x)) -#define htole64(x) ((uint64_t)(x)) - -#define be16toh(x) __bswap16((x)) -#define be32toh(x) __bswap32((x)) -#define be64toh(x) __bswap64((x)) -#define le16toh(x) ((uint16_t)(x)) -#define le32toh(x) ((uint32_t)(x)) -#define le64toh(x) ((uint64_t)(x)) -#else /* _BYTE_ORDER != _LITTLE_ENDIAN */ -#define htobe16(x) ((uint16_t)(x)) -#define htobe32(x) ((uint32_t)(x)) -#define htobe64(x) ((uint64_t)(x)) -#define htole16(x) __bswap16((x)) -#define htole32(x) __bswap32((x)) -#define htole64(x) __bswap64((x)) - -#define be16toh(x) ((uint16_t)(x)) -#define be32toh(x) ((uint32_t)(x)) -#define be64toh(x) ((uint64_t)(x)) -#define le16toh(x) __bswap16((x)) -#define le32toh(x) __bswap32((x)) -#define le64toh(x) __bswap64((x)) -#endif /* _BYTE_ORDER == _LITTLE_ENDIAN */ - /* Alignment-agnostic encode/decode bytestream to/from little/big endian. */ - static __inline uint16_t be16dec(const void *pp) { @@ -203,5 +174,4 @@ le64enc(void *pp, uint64_t u) le32enc(p, (uint32_t)(u & 0xffffffffU)); le32enc(p + 4, (uint32_t)(u >> 32)); } - #endif /* _SYS_ENDIAN_H_ */