portability.h revision de699accf6804e8b1d8042b46c85500ee8c672c6 
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// For musl
8#define _ALL_SOURCE
9
10// Test for gcc (using compiler builtin #define)
11
12#ifdef __GNUC__
13#define noreturn	__attribute__((noreturn))
14#else
15#define noreturn
16#endif
17
18// Always use long file support.
19#define _FILE_OFFSET_BITS 64
20
21// This isn't in the spec, but it's how we determine what libc we're using.
22
23#include <features.h>
24
25// Various constants old build environments might not have even if kernel does
26
27#ifndef AT_FDCWD
28#define AT_FDCWD -100
29#endif
30
31#ifndef AT_SYMLINK_NOFOLLOW
32#define AT_SYMLINK_NOFOLLOW 0x100
33#endif
34
35#ifndef AT_REMOVEDIR
36#define AT_REMOVEDIR 0x200
37#endif
38
39// We don't define GNU_dammit because we're not part of the gnu project, and
40// don't want to get any FSF on us. Unfortunately glibc (gnu libc)
41// won't give us Linux syscall wrappers without claiming to be part of the
42// gnu project (because Stallman's "GNU owns Linux" revisionist history
43// crusade includes the kernel, even though Linux was inspired by Minix).
44
45// We use most non-posix Linux syscalls directly through the syscall() wrapper,
46// but even many posix-2008 functions aren't provided by glibc unless you
47// claim it's in the name of Gnu.
48
49#if defined(__GLIBC__)
50// "Function prototypes shall be provided." but aren't.
51// http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/unistd.h.html
52char *crypt(const char *key, const char *salt);
53
54// According to posix, #include header, get a function definition. But glibc...
55// http://pubs.opengroup.org/onlinepubs/9699919799/functions/wcwidth.html
56#include <wchar.h>
57int wcwidth(wchar_t wc);
58
59// see http://pubs.opengroup.org/onlinepubs/9699919799/functions/strptime.html
60#include <time.h>
61char *strptime(const char *buf, const char *format, struct tm *tm);
62
63// They didn't like posix basename so they defined another function with the
64// same name and if you include libgen.h it #defines basename to something
65// else (where they implemented the real basename), and that define breaks
66// the table entry for the basename command. They didn't make a new function
67// with a different name for their new behavior because gnu.
68//
69// Implement our own in portability.c and don't use their broken header.
70char *basename(char *path);
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#include <sys/mount.h>
85#ifndef MS_MOVE
86#define MS_MOVE       (1<<13)
87#endif
88#ifndef MS_REC
89#define MS_REC        (1<<14)
90#endif
91#ifndef MS_SILENT
92#define MS_SILENT     (1<<15)
93#endif
94#ifndef MS_UNBINDABLE
95#define MS_UNBINDABLE (1<<17)
96#endif
97#ifndef MS_PRIVATE
98#define MS_PRIVATE    (1<<18)
99#endif
100#ifndef MS_SLAVE
101#define MS_SLAVE      (1<<19)
102#endif
103#ifndef MS_SHARED
104#define MS_SHARED     (1<<20)
105#endif
106
107// When building under obsolete glibc (Ubuntu 8.04-ish), hold its hand a bit.
108#elif __GLIBC__ == 2 && __GLIBC_MINOR__ < 10
109#define fstatat fstatat64
110int fstatat64(int dirfd, const char *pathname, void *buf, int flags);
111int readlinkat(int dirfd, const char *pathname, char *buf, size_t bufsiz);
112char *stpcpy(char *dest, const char *src);
113#include <sys/stat.h>
114int fchmodat(int dirfd, const char *pathname, mode_t mode, int flags);
115int openat(int dirfd, const char *pathname, int flags, ...);
116#include <dirent.h>
117DIR *fdopendir(int fd);
118#include <unistd.h>
119int fchownat(int dirfd, const char *pathname,
120                    uid_t owner, gid_t group, int flags);
121int isblank(int c);
122int unlinkat(int dirfd, const char *pathname, int flags);
123#include <stdio.h>
124ssize_t getdelim(char **lineptr, size_t *n, int delim, FILE *stream);
125
126// Straight from posix-2008, things old glibc had but didn't prototype
127
128int faccessat(int fd, const char *path, int amode, int flag);
129int linkat(int fd1, const char *path1, int fd2, const char *path2, int flag);
130int mkdirat(int fd, const char *path, mode_t mode);
131int symlinkat(const char *path1, int fd, const char *path2);
132int mknodat(int fd, const char *path, mode_t mode, dev_t dev);
133#include <sys/time.h>
134int futimens(int fd, const struct timespec times[2]);
135int utimensat(int fd, const char *path, const struct timespec times[2], int flag);
136
137#ifndef MNT_DETACH
138#define MNT_DETACH 2
139#endif
140#endif
141
142#endif
143
144#ifdef __MUSL__
145#include <unistd.h>
146// Without this "rm -r dir" fails with "is directory".
147#define faccessat(A, B, C, D) faccessat(A, B, C, 0)
148#endif
149
150// Work out how to do endianness
151
152#ifndef __APPLE__
153#include <byteswap.h>
154#include <endian.h>
155
156#if __BYTE_ORDER == __BIG_ENDIAN
157#define IS_BIG_ENDIAN 1
158#else
159#define IS_BIG_ENDIAN 0
160#endif
161
162int clearenv(void);
163#else
164
165#ifdef __BIG_ENDIAN__
166#define IS_BIG_ENDIAN 1
167#else
168#define IS_BIG_ENDIAN 0
169#endif
170
171#endif
172
173#if IS_BIG_ENDIAN
174#define IS_LITTLE_ENDIAN 0
175#define SWAP_BE16(x) (x)
176#define SWAP_BE32(x) (x)
177#define SWAP_BE64(x) (x)
178#define SWAP_LE16(x) bswap_16(x)
179#define SWAP_LE32(x) bswap_32(x)
180#define SWAP_LE64(x) bswap_64(x)
181#else
182#define IS_LITTLE_ENDIAN 1
183#define SWAP_BE16(x) bswap_16(x)
184#define SWAP_BE32(x) bswap_32(x)
185#define SWAP_BE64(x) bswap_64(x)
186#define SWAP_LE16(x) (x)
187#define SWAP_LE32(x) (x)
188#define SWAP_LE64(x) (x)
189#endif
190
191#if defined(__APPLE__) \
192    || (defined(__GLIBC__) && __GLIBC__ == 2 && __GLIBC_MINOR__ < 10)
193ssize_t getdelim(char **lineptr, size_t *n, int delim, FILE *stream);
194ssize_t getline(char **lineptr, size_t *n, FILE *stream);
195#endif
196
197// Linux headers not listed by POSIX or LSB
198#include <sys/mount.h>
199#include <sys/swap.h>
200
201// Android is missing some headers and functions
202// "generated/config.h" is included first
203#if CFG_TOYBOX_SHADOW
204#include <shadow.h>
205#endif
206#if CFG_TOYBOX_UTMPX
207#include <utmpx.h>
208#endif
209#if CFG_TOYBOX_PTY
210#include <pty.h>
211#else
212pid_t forkpty(int *amaster, char *name, void *termp, void *winp);
213#endif
214
215
216// Some systems don't define O_NOFOLLOW, and it varies by architecture, so...
217#include <fcntl.h>
218#ifndef O_NOFOLLOW
219#define O_NOFOLLOW 0
220#endif
221
222#ifndef O_CLOEXEC
223#define O_CLOEXEC 02000000
224#endif
225
226#if defined(__SIZEOF_DOUBLE__) && defined(__SIZEOF_LONG__) \
227    && __SIZEOF_DOUBLE__ <= __SIZEOF_LONG__
228typedef double FLOAT;
229#else
230typedef float FLOAT;
231#endif
232
233#ifndef __uClinux__
234pid_t xfork(void);
235#endif
236
237//#define strncpy(...) @@strncpyisbadmmkay@@
238//#define strncat(...) @@strcatisbadmmkay@@
239