portability.h revision a1a83e671fdd91dcb763651ac86295c217574e6e 
1// Workarounds for horrible build environment idiosyncrasies.
2
3// Instead of polluting the code with strange #ifdefs to work around bugs
4// in specific compiler, library, or OS versions, localize all that here
5// and in portability.c
6
7// The tendency of gcc to produce stupid warnings continues with
8// warn_unused_result, which warns about things like ignoring the return code
9// of nice(2) (which is completely useless since -1 is a legitimate return
10// value on success and even the man page tells you to use errno instead).
11
12// This makes it stop.
13
14#undef _FORTIFY_SOURCE
15
16// For musl
17#define _ALL_SOURCE
18
19// Test for gcc (using compiler builtin #define)
20
21#ifdef __GNUC__
22#define noreturn	__attribute__((noreturn))
23#else
24#define noreturn
25#endif
26
27// Always use long file support.
28#define _FILE_OFFSET_BITS 64
29
30// This isn't in the spec, but it's how we determine what libc we're using.
31
32#include <features.h>
33
34// Various constants old build environments might not have even if kernel does
35
36#ifndef AT_FDCWD
37#define AT_FDCWD -100
38#endif
39
40#ifndef AT_SYMLINK_NOFOLLOW
41#define AT_SYMLINK_NOFOLLOW 0x100
42#endif
43
44#ifndef AT_REMOVEDIR
45#define AT_REMOVEDIR 0x200
46#endif
47
48// We don't define GNU_dammit because we're not part of the gnu project, and
49// don't want to get any FSF on us. Unfortunately glibc (gnu libc)
50// won't give us Linux syscall wrappers without claiming to be part of the
51// gnu project (because Stallman's "GNU owns Linux" revisionist history
52// crusade includes the kernel, even though Linux was inspired by Minix).
53
54// We use most non-posix Linux syscalls directly through the syscall() wrapper,
55// but even many posix-2008 functions aren't provided by glibc unless you
56// claim it's in the name of Gnu.
57
58#if defined(__GLIBC__)
59// "Function prototypes shall be provided." but aren't.
60// http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/unistd.h.html
61char *crypt(const char *key, const char *salt);
62
63// According to posix, #include header, get a function definition. But glibc...
64// http://pubs.opengroup.org/onlinepubs/9699919799/functions/wcwidth.html
65#include <wchar.h>
66int wcwidth(wchar_t wc);
67
68// see http://pubs.opengroup.org/onlinepubs/9699919799/functions/strptime.html
69#include <time.h>
70char *strptime(const char *buf, const char *format, struct tm *tm);
71
72// uClibc pretends to be glibc and copied a lot of its bugs, but has a few more
73#if defined(__UCLIBC__)
74#include <unistd.h>
75#include <stdio.h>
76ssize_t getdelim(char **lineptr, size_t *n, int delim, FILE *stream);
77char *stpcpy(char *dest, const char *src);
78pid_t getsid(pid_t pid);
79
80// uClibc's last-ever release was in 2012, so of course it doesn't define
81// any flag newer than MS_MOVE, which was added in 2001 (linux 2.5.0.5),
82// eleven years earlier.
83
84#define MS_MOVE       (1<<13)
85#define MS_REC        (1<<14)
86#define MS_SILENT     (1<<15)
87#define MS_UNBINDABLE (1<<17)
88#define MS_PRIVATE    (1<<18)
89#define MS_SLAVE      (1<<19)
90#define MS_SHARED     (1<<20)
91
92// When building under obsolete glibc (Ubuntu 8.04-ish), hold its hand a bit.
93#elif __GLIBC__ == 2 && __GLIBC_MINOR__ < 10
94#define fstatat fstatat64
95int fstatat64(int dirfd, const char *pathname, void *buf, int flags);
96int readlinkat(int dirfd, const char *pathname, char *buf, size_t bufsiz);
97char *stpcpy(char *dest, const char *src);
98#include <sys/stat.h>
99int fchmodat(int dirfd, const char *pathname, mode_t mode, int flags);
100int openat(int dirfd, const char *pathname, int flags, ...);
101#include <dirent.h>
102DIR *fdopendir(int fd);
103#include <unistd.h>
104int fchownat(int dirfd, const char *pathname,
105                    uid_t owner, gid_t group, int flags);
106int isblank(int c);
107int unlinkat(int dirfd, const char *pathname, int flags);
108#include <stdio.h>
109ssize_t getdelim(char **lineptr, size_t *n, int delim, FILE *stream);
110
111// Straight from posix-2008, things old glibc had but didn't prototype
112
113int faccessat(int fd, const char *path, int amode, int flag);
114int linkat(int fd1, const char *path1, int fd2, const char *path2, int flag);
115int mkdirat(int fd, const char *path, mode_t mode);
116int symlinkat(const char *path1, int fd, const char *path2);
117int mknodat(int fd, const char *path, mode_t mode, dev_t dev);
118#include <sys/time.h>
119int futimens(int fd, const struct timespec times[2]);
120int utimensat(int fd, const char *path, const struct timespec times[2], int flag);
121
122#ifndef MNT_DETACH
123#define MNT_DETACH 2
124#endif
125#endif
126
127#endif
128
129// Work out how to do endianness
130
131#ifndef __APPLE__
132#include <byteswap.h>
133#include <endian.h>
134
135#if __BYTE_ORDER == __BIG_ENDIAN
136#define IS_BIG_ENDIAN 1
137#else
138#define IS_BIG_ENDIAN 0
139#endif
140
141int clearenv(void);
142#else
143
144#ifdef __BIG_ENDIAN__
145#define IS_BIG_ENDIAN 1
146#else
147#define IS_BIG_ENDIAN 0
148#endif
149
150#endif
151
152#if IS_BIG_ENDIAN
153#define IS_LITTLE_ENDIAN 0
154#define SWAP_BE16(x) (x)
155#define SWAP_BE32(x) (x)
156#define SWAP_BE64(x) (x)
157#define SWAP_LE16(x) bswap_16(x)
158#define SWAP_LE32(x) bswap_32(x)
159#define SWAP_LE64(x) bswap_64(x)
160#else
161#define IS_LITTLE_ENDIAN 1
162#define SWAP_BE16(x) bswap_16(x)
163#define SWAP_BE32(x) bswap_32(x)
164#define SWAP_BE64(x) bswap_64(x)
165#define SWAP_LE16(x) (x)
166#define SWAP_LE32(x) (x)
167#define SWAP_LE64(x) (x)
168#endif
169
170#if defined(__APPLE__) || defined(__ANDROID__) \
171    || (defined(__GLIBC__) && __GLIBC__ == 2 && __GLIBC_MINOR__ < 10)
172ssize_t getdelim(char **lineptr, size_t *n, int delim, FILE *stream);
173ssize_t getline(char **lineptr, size_t *n, FILE *stream);
174#endif
175
176// Linux headers not listed by POSIX or LSB
177#include <shadow.h>
178#include <sys/mount.h>
179#include <sys/swap.h>
180
181// Some systems don't define O_NOFOLLOW, and it varies by architecture, so...
182#include <fcntl.h>
183#ifndef O_NOFOLLOW
184#define O_NOFOLLOW 0
185#endif
186
187#ifndef O_CLOEXEC
188#define O_CLOEXEC 02000000
189#endif
190
191#if defined(__SIZEOF_DOUBLE__) && defined(__SIZEOF_LONG__) \
192    && __SIZEOF_DOUBLE__ <= __SIZEOF_LONG__
193typedef double FLOAT;
194#else
195typedef float FLOAT;
196#endif
197
198