Annotation of dietlibc/dietfeatures.h, revision 1.79
1.4 fefe 1: #ifndef _DIETFEATURES_H
2: #define _DIETFEATURES_H
1.1 cvs 3:
4: /* feel free to comment some of these out to reduce code size */
5:
1.78 leitner 6: /* On i386, BSD socket syscalls have traditionally been implemented via
7: * a multiplexing syscall called "socketcall". But somewhere in the 3.x
8: * cycle, Linux got real syscalls for socket(), accept() etc, and now
9: * it would make sense to use those syscalls instead, if only to make
10: * seccomp sandboxes more platform agnostic. However, if you plan on
11: * running your program on an ancient kernel, you need the socketcall
12: * version instead. */
13: #define WANT_I386_SOCKETCALL
14:
1.13 fefe 15: #define WANT_FLOATING_POINT_IN_PRINTF
16: #define WANT_FLOATING_POINT_IN_SCANF
1.12 fefe 17: #define WANT_CHARACTER_CLASSES_IN_SCANF
1.1 cvs 18: #define WANT_NULL_PRINTF
1.52 sanjiyan 19: /* #define WANT_ERROR_PRINTF */
1.24 fefe 20: #define WANT_LONGLONG_PRINTF
1.42 olaf 21: #define WANT_LONGLONG_SCANF
1.1 cvs 22:
1.20 fefe 23: /* 128 or 2048 bytes buffer size? */
24: /* #define WANT_SMALL_STDIO_BUFS */
25:
1.40 fefe 26: /* want fread to read() directly if size of data is larger than buffer?
27: * This costs a few bytes but is worth it if the application is already
28: * buffering. */
29: #define WANT_FREAD_OPTIMIZATION
30:
1.34 fefe 31: /* this is only for meaningful for ttyname and sysconf_cpus so far */
1.40 fefe 32: #define SLASH_PROC_OK
1.1 cvs 33:
1.65 leitner 34: /* use errno_location instead of errno; NEEDED FOR MULTI-THREADING! */
1.20 fefe 35: #define WANT_THREAD_SAFE
1.1 cvs 36:
1.65 leitner 37: /* support __thread; NEEDED FOR MULTI-THREADING! */
1.64 leitner 38: #define WANT_TLS
39:
1.35 olaf 40: /* make the startcode, etc. dynamic aware ({con,de}structors) */
1.76 leitner 41: // #define WANT_DYNAMIC
1.1 cvs 42:
1.57 leitner 43: /* GDB support in the dynamic linker */
44: #define WANT_LD_SO_GDB_SUPPORT
45:
1.1 cvs 46: /* do you want smaller or faster string routines? */
1.63 leitner 47: #define WANT_FASTER_STRING_ROUTINES
1.1 cvs 48:
1.77 leitner 49: /* define this to have strncpy and stpncpy zero-fill and not just
50: * zero-terminate the destination string */
1.43 fefe 51: /* #define WANT_FULL_POSIX_COMPAT */
52:
1.47 leitner 53: /* on i386, Linux has an alternate syscall method since 2002/12/16 */
54: /* on my Athlon XP, it is twice as fast, but it's only in kernel 2.5 */
1.53 leitner 55: /* 20040118: enabling this breaks User Mode Linux! It's their fault. */
1.48 leitner 56: #define WANT_SYSENTER
1.47 leitner 57:
1.4 fefe 58: #define WANT_LINKER_WARNINGS
59:
1.7 fefe 60: /* you need to define this if you want to run your programs with large
1.31 fefe 61: * file support on kernel 2.2 or 2.0 */
1.7 fefe 62: #define WANT_LARGEFILE_BACKCOMPAT
63:
1.8 fefe 64: /* do you want localtime(3) to read /etc/localtime?
65: * Needed for daylight saving time etc. */
66: #define WANT_TZFILE_PARSER
1.1 cvs 67:
1.21 fefe 68: /* do you want the DNS routines to parse and use "domain" and "search"
69: * lines from /etc/resolv.conf? Normally not used on boot floppies and
70: * embedded environments. */
71: #define WANT_FULL_RESOLV_CONF
72:
1.45 fefe 73: /* do you want IPv6 transport support in the DNS resolver? */
74: #define WANT_IPV6_DNS
75:
1.27 fefe 76: /* do you want gethostbyname and friends to consult /etc/hosts? */
77: #define WANT_ETC_HOSTS
78:
1.46 fefe 79: /* do you want gethostbyname to understand dotted decimal IP numbers
80: * directly and not try to resolve them? */
81: #define WANT_INET_ADDR_DNS
82:
1.29 fefe 83: /* do you want math functions high precision rather than fast/small? */
84: #define WANT_HIGH_PRECISION_MATH
85:
86: /* do you want support for matherr? */
87: #define WANT_MATHERR
88:
1.30 fefe 89: /* do you want crypt(3) to use MD5 if the salt starts with "$1$"? */
90: #define WANT_CRYPT_MD5
91:
1.77 leitner 92: /* do you want crypt(3) to use SHA256 if the salt starts with "$5$? */
93: #define WANT_CRYPT_SHA256
94:
95: /* do you want crypt(3) to use SHA512 if the salt starts with "$6$? */
96: #define WANT_CRYPT_SHA512
97:
1.32 fefe 98: /* do you want diet to include a safeguard dependency to make linking
1.45 fefe 99: * against glibc fail? This may fail with older binutils. */
1.32 fefe 100: #define WANT_SAFEGUARD
1.38 olaf 101:
1.60 leitner 102: /* This enables zeroconf DNS aka Rendezvous aka Bonjour. */
103: /* This code will try zeroconf DNS if you ask for host.local or if you
104: * ask for an unqualified hostname */
1.59 leitner 105: #define WANT_PLUGPLAY_DNS
1.49 leitner 106:
1.68 leitner 107: /* This enables LLMNR, the MS variant of zeroconf DNS. This only works
108: * if you also enabled WANT_PLUGPLAY_DNS */
109: #define WANT_LLMNR
110:
1.70 leitner 111: /* Uncomment this if you want DNS lookups to fail if /etc/hosts contains
112: * an entry but it's for a different record type */
113: /* #define WANT_HOSTS_GIVEUP_EARLY */
114:
1.67 leitner 115: /* Do you want valgrind support? If enabled, the startup code will
116: * check for valgrind, and if detected, turn off optimized SIMD string
117: * routines that cause false positives in valgrind. This enlarges and
118: * slightly slows down your code! */
119: #define WANT_VALGRIND_SUPPORT
120:
1.54 leitner 121: /* do you want that malloc(0) return a pointer to a "zero-length" object
1.38 olaf 122: * that is realloc-able; means realloc(..,size) gives a NEW object (like a
123: * call to malloc(size)).
124: * WARNING: this violates C99 */
125: /* #define WANT_MALLOC_ZERO */
126:
1.62 leitner 127: /* do you want free to overwrite freed data immediately, in the hope of
128: * catching people accessing pointers after they were freed? This does
129: * a memset with 0x55 as a value. which is not NULL and not -1. Please
130: * note that this is the shotgun method for debugging, what you really
131: * want is valgrind. */
132: /* #define WANT_FREE_OVERWRITE */
133:
1.54 leitner 134: /* This enables a stack gap. Basically, the start code does not run
135: * main but stackgap, which then does alloca(random()) and calls main.
136: * The effect is that buffer overflow exploits will no longer be able to
137: * know the address of the buffer. Cost: 62 bytes code on x86. */
1.56 leitner 138: /* WARNING: this appears to break with some binutils versions. Works
139: * for me with binutils 2.15. The symptom is an error message that
140: * `main' can not be found. */
1.58 leitner 141: /* #define WANT_STACKGAP */
1.32 fefe 142:
1.79 ! leitner 143: /* For SSP initialization, dietlibc usually uses randomness given by the
! 144: * kernel in the ELF auxvec. Some very old kernels do not pass this, and
! 145: * for them dietlibc will open /dev/urandom to get randomness. Undef
! 146: * this if you don't need that bloat. */
! 147: // #define WANT_URANDOM_SSP
! 148:
1.69 leitner 149: /* #define this if you want GNU bloat like program_invocation_short_name
150: * and program_invocation_name to be there. This functionality is not
151: * portable and adds useless bloat to libc. Help stomp out code
152: * depending on this! util-linux, I'm looking at you here! */
153: #define WANT_GNU_STARTUP_BLOAT
154:
1.61 leitner 155: /* Include support for ProPolice/SSP, calls guard_setup */
156: /* ProPolice is part of gcc 4.1 and up, there were patches for earlier
157: * versions. To make use of this, compile your application with
1.64 leitner 158: * -fstack-protector. */
1.66 leitner 159: /* If you compile dietlibc without WANT_SSP and then try to link code
160: * compiled with -fstack-protector against it, the binary will segfault
161: * when calling that code. */
1.61 leitner 162: #if (__GNUC__>4) || ((__GNUC__==4) && (__GNUC_MINOR__>=1))
163: #define WANT_SSP
164: #endif
165:
166:
167:
1.1 cvs 168: /* stop uncommenting here ;-) */
1.72 sanjiyan 169:
170: /* Several 'syscalls' on x86_64 need vdso set... */
171: #if defined(__x86_64__) && ! defined(WANT_STACKGAP)
172: #define WANT_STACKGAP
173: #endif
174:
1.70 leitner 175: #if defined(WANT_SSP) || defined(WANT_STACKGAP) || defined(WANT_TLS)
1.61 leitner 176: #define CALL_IN_STARTCODE stackgap
1.77 leitner 177: #define CALL_IN_STARTCODE_PIE stackgap_pie
1.61 leitner 178: #else
179: #define CALL_IN_STARTCODE main
180: #endif
181:
1.1 cvs 182: #ifndef WANT_FASTER_STRING_ROUTINES
183: #define WANT_SMALL_STRING_ROUTINES
1.4 fefe 184: #endif
185:
1.33 olaf 186: #ifdef __DYN_LIB
1.39 olaf 187: /* with shared libraries you MUST have a dynamic aware startcode */
1.33 olaf 188: #ifndef WANT_DYNAMIC
189: #define WANT_DYNAMIC
1.35 olaf 190: #endif
1.79 ! leitner 191: /* safeguard crashes with shared objects ... */
1.35 olaf 192: #ifdef WANT_SAFEGUARD
193: #undef WANT_SAFEGUARD
1.33 olaf 194: #endif
195: #endif
196:
1.73 leitner 197: #if defined(__x86_64__) && defined(__ILP32__)
198: #undef WANT_LARGEFILE_BACKCOMPAT
199: #endif
200:
1.1 cvs 201: #endif
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