posix/confstr.c

   1 /* Copyright (C) 1991-2014 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #include <stddef.h>
  19 #include <errno.h>
  20 #include <unistd.h>
  21 #include <string.h>
  22 #include <confstr.h>
  23 #include "../version.h"
  24 #include <posix-conf-vars.h>
  25
  26 /* If BUF is not NULL and LEN > 0, fill in at most LEN - 1 bytes
  27    of BUF with the value corresponding to NAME and zero-terminate BUF.
  28    Return the number of bytes required to hold NAME's entire value.  */
  29 size_t
  30 confstr (name, buf, len)
  31      int name;
  32      char *buf;
  33      size_t len;
  34 {
  35   const char *string = "";
  36   size_t string_len = 1;
  37
  38   /* Note that this buffer must be large enough for the longest strings
  39      used below.  */
  40   char restenvs[4 * sizeof "POSIX_V7_LPBIG_OFFBIG"];
  41
  42   switch (name)
  43     {
  44     case _CS_PATH:
  45       {
  46         static const char cs_path[] = CS_PATH;
  47         string = cs_path;
  48         string_len = sizeof (cs_path);
  49       }
  50       break;
  51
  52       /* For _CS_V7_WIDTH_RESTRICTED_ENVS, _CS_V6_WIDTH_RESTRICTED_ENVS
  53          and _CS_V5_WIDTH_RESTRICTED_ENVS:
  54
  55          We have to return a newline-separated list of names of
  56          programming environments in which the widths of blksize_t,
  57          cc_t, mode_t, nfds_t, pid_t, ptrdiff_t, size_t, speed_t,
  58          ssize_t, suseconds_t, tcflag_t, useconds_t, wchar_t, and
  59          wint_t types are no greater than the width of type long.
  60
  61          Currently this means all environments that the system allows.  */
  62
  63 #define START_ENV_GROUP(VERSION)                \
  64     case _CS_##VERSION##_WIDTH_RESTRICTED_ENVS: \
  65       string_len = 0;
  66
  67 #define END_ENV_GROUP(VERSION)                  \
  68       restenvs[string_len++] = '\0';            \
  69       string = restenvs;                        \
  70       break;
  71
  72 #define KNOWN_ABSENT_ENVIRONMENT(SC_PREFIX, ENV_PREFIX, SUFFIX) \
  73       /* Empty.  */
  74
  75 #define KNOWN_PRESENT_ENV_STRING(STR)           \
  76       if (string_len > 0)                       \
  77         restenvs[string_len++] = '\n';          \
  78       memcpy (restenvs + string_len, STR,       \
  79               sizeof STR - 1);                  \
  80       string_len += sizeof STR - 1;
  81
  82 #define KNOWN_PRESENT_ENVIRONMENT(SC_PREFIX, ENV_PREFIX, SUFFIX)        \
  83       KNOWN_PRESENT_ENV_STRING (#ENV_PREFIX "_" #SUFFIX)
  84
  85 #define UNKNOWN_ENVIRONMENT(SC_PREFIX, ENV_PREFIX, SUFFIX)              \
  86       if (__sysconf (_SC_##SC_PREFIX##_##SUFFIX) > 0)                   \
  87         {                                                               \
  88           KNOWN_PRESENT_ENVIRONMENT (SC_PREFIX, ENV_PREFIX, SUFFIX)     \
  89         }
  90
  91 #include "posix-envs.def"
  92
  93 #undef START_ENV_GROUP
  94 #undef END_ENV_GROUP
  95 #undef KNOWN_ABSENT_ENVIRONMENT
  96 #undef KNOWN_PRESENT_ENV_STRING
  97 #undef KNOWN_PRESENT_ENVIRONMENT
  98 #undef UNKNOWN_ENVIRONMENT
  99
 100     case _CS_XBS5_ILP32_OFF32_CFLAGS:
 101     case _CS_POSIX_V6_ILP32_OFF32_CFLAGS:
 102     case _CS_POSIX_V7_ILP32_OFF32_CFLAGS:
 103 #ifdef __ILP32_OFF32_CFLAGS
 104 # if CONF_IS_DEFINED_UNSET (_POSIX_V7_ILP32_OFF32)
 105 #  error "__ILP32_OFF32_CFLAGS should not be defined"
 106 # elif CONF_IS_UNDEFINED (_POSIX_V7_ILP32_OFF32)
 107       if (__sysconf (_SC_V7_ILP32_OFF32) < 0)
 108         break;
 109 # endif
 110       string = __ILP32_OFF32_CFLAGS;
 111       string_len = sizeof (__ILP32_OFF32_CFLAGS);
 112 #endif
 113       break;
 114
 115     case _CS_XBS5_ILP32_OFFBIG_CFLAGS:
 116     case _CS_POSIX_V6_ILP32_OFFBIG_CFLAGS:
 117     case _CS_POSIX_V7_ILP32_OFFBIG_CFLAGS:
 118 #ifdef __ILP32_OFFBIG_CFLAGS
 119 # if CONF_IS_DEFINED_UNSET (_POSIX_V7_ILP32_OFFBIG)
 120 #  error "__ILP32_OFFBIG_CFLAGS should not be defined"
 121 # elif CONF_IS_UNDEFINED (_POSIX_V7_ILP32_OFFBIG)
 122       if (__sysconf (_SC_V7_ILP32_OFFBIG) < 0)
 123         break;
 124 # endif
 125       string = __ILP32_OFFBIG_CFLAGS;
 126       string_len = sizeof (__ILP32_OFFBIG_CFLAGS);
 127 #endif
 128       break;
 129
 130     case _CS_XBS5_LP64_OFF64_CFLAGS:
 131     case _CS_POSIX_V6_LP64_OFF64_CFLAGS:
 132     case _CS_POSIX_V7_LP64_OFF64_CFLAGS:
 133 #ifdef __LP64_OFF64_CFLAGS
 134 # if CONF_IS_DEFINED_UNSET (_POSIX_V7_LP64_OFF64)
 135 #  error "__LP64_OFF64_CFLAGS should not be defined"
 136 # elif CONF_IS_UNDEFINED (_POSIX_V7_LP64_OFF64)
 137       if (__sysconf (_SC_V7_LP64_OFF64) < 0)
 138         break;
 139 # endif
 140       string = __LP64_OFF64_CFLAGS;
 141       string_len = sizeof (__LP64_OFF64_CFLAGS);
 142 #endif
 143       break;
 144
 145     case _CS_XBS5_ILP32_OFF32_LDFLAGS:
 146     case _CS_POSIX_V6_ILP32_OFF32_LDFLAGS:
 147     case _CS_POSIX_V7_ILP32_OFF32_LDFLAGS:
 148 #ifdef __ILP32_OFF32_LDFLAGS
 149 # if CONF_IS_DEFINED_UNSET (_POSIX_V7_ILP32_OFF32 )
 150 #  error "__ILP32_OFF32_LDFLAGS should not be defined"
 151 # elif CONF_IS_UNDEFINED (_POSIX_V7_ILP32_OFF32)
 152       if (__sysconf (_SC_V7_ILP32_OFF32) < 0)
 153         break;
 154 # endif
 155       string = __ILP32_OFF32_LDFLAGS;
 156       string_len = sizeof (__ILP32_OFF32_LDFLAGS);
 157 #endif
 158       break;
 159
 160     case _CS_XBS5_ILP32_OFFBIG_LDFLAGS:
 161     case _CS_POSIX_V6_ILP32_OFFBIG_LDFLAGS:
 162     case _CS_POSIX_V7_ILP32_OFFBIG_LDFLAGS:
 163 #ifdef __ILP32_OFFBIG_LDFLAGS
 164 # if CONF_IS_DEFINED_UNSET (_POSIX_V7_ILP32_OFFBIG)
 165 #  error "__ILP32_OFFBIG_LDFLAGS should not be defined"
 166 # elif CONF_IS_UNDEFINED (_POSIX_V7_ILP32_OFFBIG)
 167       if (__sysconf (_SC_V7_ILP32_OFFBIG) < 0)
 168         break;
 169 # endif
 170       string = __ILP32_OFFBIG_LDFLAGS;
 171       string_len = sizeof (__ILP32_OFFBIG_LDFLAGS);
 172 #endif
 173       break;
 174
 175     case _CS_XBS5_LP64_OFF64_LDFLAGS:
 176     case _CS_POSIX_V6_LP64_OFF64_LDFLAGS:
 177     case _CS_POSIX_V7_LP64_OFF64_LDFLAGS:
 178 #ifdef __LP64_OFF64_LDFLAGS
 179 # if CONF_IS_DEFINED_UNSET (_POSIX_V7_LP64_OFF64)
 180 #  error "__LP64_OFF64_LDFLAGS should not be defined"
 181 # elif CONF_IS_UNDEFINED (_POSIX_V7_LP64_OFF64)
 182       if (__sysconf (_SC_V7_LP64_OFF64) < 0)
 183         break;
 184 # endif
 185       string = __LP64_OFF64_LDFLAGS;
 186       string_len = sizeof (__LP64_OFF64_LDFLAGS);
 187 #endif
 188       break;
 189
 190     case _CS_LFS_CFLAGS:
 191     case _CS_LFS_LINTFLAGS:
 192 #if (CONF_IS_DEFINED_SET (_POSIX_V6_ILP32_OFF32) \
 193      && CONF_IS_DEFINED_SET (_POSIX_V6_ILP32_OFFBIG))
 194 # define __LFS_CFLAGS "-D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64"
 195       /* Signal that we want the new ABI.  */
 196       string = __LFS_CFLAGS;
 197       string_len = sizeof (__LFS_CFLAGS);
 198 #endif
 199       break;
 200
 201     case _CS_LFS_LDFLAGS:
 202     case _CS_LFS_LIBS:
 203       /* No special libraries or linker flags needed.  */
 204       break;
 205
 206     case _CS_LFS64_CFLAGS:
 207     case _CS_LFS64_LINTFLAGS:
 208 #define __LFS64_CFLAGS "-D_LARGEFILE64_SOURCE"
 209       string = __LFS64_CFLAGS;
 210       string_len = sizeof (__LFS64_CFLAGS);
 211       break;
 212
 213     case _CS_LFS64_LDFLAGS:
 214     case _CS_LFS64_LIBS:
 215       /* No special libraries or linker flags needed.  */
 216       break;
 217
 218     case _CS_XBS5_ILP32_OFF32_LIBS:
 219     case _CS_XBS5_ILP32_OFF32_LINTFLAGS:
 220     case _CS_XBS5_ILP32_OFFBIG_LIBS:
 221     case _CS_XBS5_ILP32_OFFBIG_LINTFLAGS:
 222     case _CS_XBS5_LP64_OFF64_LIBS:
 223     case _CS_XBS5_LP64_OFF64_LINTFLAGS:
 224     case _CS_XBS5_LPBIG_OFFBIG_CFLAGS:
 225     case _CS_XBS5_LPBIG_OFFBIG_LDFLAGS:
 226     case _CS_XBS5_LPBIG_OFFBIG_LIBS:
 227     case _CS_XBS5_LPBIG_OFFBIG_LINTFLAGS:
 228
 229     case _CS_POSIX_V6_ILP32_OFF32_LIBS:
 230     case _CS_POSIX_V6_ILP32_OFF32_LINTFLAGS:
 231     case _CS_POSIX_V6_ILP32_OFFBIG_LIBS:
 232     case _CS_POSIX_V6_ILP32_OFFBIG_LINTFLAGS:
 233     case _CS_POSIX_V6_LP64_OFF64_LIBS:
 234     case _CS_POSIX_V6_LP64_OFF64_LINTFLAGS:
 235     case _CS_POSIX_V6_LPBIG_OFFBIG_CFLAGS:
 236     case _CS_POSIX_V6_LPBIG_OFFBIG_LDFLAGS:
 237     case _CS_POSIX_V6_LPBIG_OFFBIG_LIBS:
 238     case _CS_POSIX_V6_LPBIG_OFFBIG_LINTFLAGS:
 239
 240     case _CS_POSIX_V7_ILP32_OFF32_LIBS:
 241     case _CS_POSIX_V7_ILP32_OFF32_LINTFLAGS:
 242     case _CS_POSIX_V7_ILP32_OFFBIG_LIBS:
 243     case _CS_POSIX_V7_ILP32_OFFBIG_LINTFLAGS:
 244     case _CS_POSIX_V7_LP64_OFF64_LIBS:
 245     case _CS_POSIX_V7_LP64_OFF64_LINTFLAGS:
 246     case _CS_POSIX_V7_LPBIG_OFFBIG_CFLAGS:
 247     case _CS_POSIX_V7_LPBIG_OFFBIG_LDFLAGS:
 248     case _CS_POSIX_V7_LPBIG_OFFBIG_LIBS:
 249     case _CS_POSIX_V7_LPBIG_OFFBIG_LINTFLAGS:
 250       /* GNU libc does not require special actions to use LFS functions.  */
 251       break;
 252
 253     case _CS_GNU_LIBC_VERSION:
 254       string = "glibc " VERSION;
 255       string_len = sizeof ("glibc " VERSION);
 256       break;
 257
 258     case _CS_GNU_LIBPTHREAD_VERSION:
 259 #ifdef LIBPTHREAD_VERSION
 260       string = LIBPTHREAD_VERSION;
 261       string_len = sizeof LIBPTHREAD_VERSION;
 262       break;
 263 #else
 264       /* No thread library.  */
 265       __set_errno (EINVAL);
 266       return 0;
 267 #endif
 268
 269     case _CS_V6_ENV:
 270     case _CS_V7_ENV:
 271       /* Maybe something else is needed in future.  */
 272       string = "POSIXLY_CORRECT=1";
 273       string_len = sizeof ("POSIXLY_CORRECT=1");
 274       break;
 275
 276     default:
 277       __set_errno (EINVAL);
 278       return 0;
 279     }
 280
 281   if (len > 0 && buf != NULL)
 282     {
 283       if (string_len <= len)
 284         memcpy (buf, string, string_len);
 285       else
 286         {
 287           memcpy (buf, string, len - 1);
 288           buf[len - 1] = '\0';
 289         }
 290     }
 291   return string_len;
 292 }
 293 libc_hidden_def (confstr)