posix/confstr.c

   1 /* Copyright (C) 1991-2017 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
  25 #define NEED_SPEC_ARRAY 0
  26 #include <posix-conf-vars.h>
  27
  28 /* If BUF is not NULL and LEN > 0, fill in at most LEN - 1 bytes
  29    of BUF with the value corresponding to NAME and zero-terminate BUF.
  30    Return the number of bytes required to hold NAME's entire value.  */
  31 size_t
  32 confstr (int name, char *buf, size_t len)
  33 {
  34   const char *string = "";
  35   size_t string_len = 1;
  36
  37   /* Note that this buffer must be large enough for the longest strings
  38      used below.  */
  39   char restenvs[4 * sizeof "POSIX_V7_LPBIG_OFFBIG"];
  40
  41   switch (name)
  42     {
  43     case _CS_PATH:
  44       {
  45         static const char cs_path[] = CS_PATH;
  46         string = cs_path;
  47         string_len = sizeof (cs_path);
  48       }
  49       break;
  50
  51       /* For _CS_V7_WIDTH_RESTRICTED_ENVS, _CS_V6_WIDTH_RESTRICTED_ENVS
  52          and _CS_V5_WIDTH_RESTRICTED_ENVS:
  53
  54          We have to return a newline-separated list of names of
  55          programming environments in which the widths of blksize_t,
  56          cc_t, mode_t, nfds_t, pid_t, ptrdiff_t, size_t, speed_t,
  57          ssize_t, suseconds_t, tcflag_t, useconds_t, wchar_t, and
  58          wint_t types are no greater than the width of type long.
  59
  60          Currently this means all environments that the system allows.  */
  61
  62 #define START_ENV_GROUP(VERSION)                \
  63     case _CS_##VERSION##_WIDTH_RESTRICTED_ENVS: \
  64       string_len = 0;
  65
  66 #define END_ENV_GROUP(VERSION)                  \
  67       restenvs[string_len++] = '\0';            \
  68       string = restenvs;                        \
  69       break;
  70
  71 #define KNOWN_ABSENT_ENVIRONMENT(SC_PREFIX, ENV_PREFIX, SUFFIX) \
  72       /* Empty.  */
  73
  74 #define KNOWN_PRESENT_ENV_STRING(STR)           \
  75       if (string_len > 0)                       \
  76         restenvs[string_len++] = '\n';          \
  77       memcpy (restenvs + string_len, STR,       \
  78               sizeof STR - 1);                  \
  79       string_len += sizeof STR - 1;
  80
  81 #define KNOWN_PRESENT_ENVIRONMENT(SC_PREFIX, ENV_PREFIX, SUFFIX)        \
  82       KNOWN_PRESENT_ENV_STRING (#ENV_PREFIX "_" #SUFFIX)
  83
  84 #define UNKNOWN_ENVIRONMENT(SC_PREFIX, ENV_PREFIX, SUFFIX)              \
  85       if (__sysconf (_SC_##SC_PREFIX##_##SUFFIX) > 0)                   \
  86         {                                                               \
  87           KNOWN_PRESENT_ENVIRONMENT (SC_PREFIX, ENV_PREFIX, SUFFIX)     \
  88         }
  89
  90 #include "posix-envs.def"
  91
  92 #undef START_ENV_GROUP
  93 #undef END_ENV_GROUP
  94 #undef KNOWN_ABSENT_ENVIRONMENT
  95 #undef KNOWN_PRESENT_ENV_STRING
  96 #undef KNOWN_PRESENT_ENVIRONMENT
  97 #undef UNKNOWN_ENVIRONMENT
  98
  99     case _CS_XBS5_ILP32_OFF32_CFLAGS:
 100     case _CS_POSIX_V6_ILP32_OFF32_CFLAGS:
 101     case _CS_POSIX_V7_ILP32_OFF32_CFLAGS:
 102 #ifdef __ILP32_OFF32_CFLAGS
 103 # if CONF_IS_DEFINED_UNSET (_POSIX_V7_ILP32_OFF32)
 104 #  error "__ILP32_OFF32_CFLAGS should not be defined"
 105 # elif CONF_IS_UNDEFINED (_POSIX_V7_ILP32_OFF32)
 106       if (__sysconf (_SC_V7_ILP32_OFF32) < 0)
 107         break;
 108 # endif
 109       string = __ILP32_OFF32_CFLAGS;
 110       string_len = sizeof (__ILP32_OFF32_CFLAGS);
 111 #endif
 112       break;
 113
 114     case _CS_XBS5_ILP32_OFFBIG_CFLAGS:
 115     case _CS_POSIX_V6_ILP32_OFFBIG_CFLAGS:
 116     case _CS_POSIX_V7_ILP32_OFFBIG_CFLAGS:
 117 #ifdef __ILP32_OFFBIG_CFLAGS
 118 # if CONF_IS_DEFINED_UNSET (_POSIX_V7_ILP32_OFFBIG)
 119 #  error "__ILP32_OFFBIG_CFLAGS should not be defined"
 120 # elif CONF_IS_UNDEFINED (_POSIX_V7_ILP32_OFFBIG)
 121       if (__sysconf (_SC_V7_ILP32_OFFBIG) < 0)
 122         break;
 123 # endif
 124       string = __ILP32_OFFBIG_CFLAGS;
 125       string_len = sizeof (__ILP32_OFFBIG_CFLAGS);
 126 #endif
 127       break;
 128
 129     case _CS_XBS5_LP64_OFF64_CFLAGS:
 130     case _CS_POSIX_V6_LP64_OFF64_CFLAGS:
 131     case _CS_POSIX_V7_LP64_OFF64_CFLAGS:
 132 #ifdef __LP64_OFF64_CFLAGS
 133 # if CONF_IS_DEFINED_UNSET (_POSIX_V7_LP64_OFF64)
 134 #  error "__LP64_OFF64_CFLAGS should not be defined"
 135 # elif CONF_IS_UNDEFINED (_POSIX_V7_LP64_OFF64)
 136       if (__sysconf (_SC_V7_LP64_OFF64) < 0)
 137         break;
 138 # endif
 139       string = __LP64_OFF64_CFLAGS;
 140       string_len = sizeof (__LP64_OFF64_CFLAGS);
 141 #endif
 142       break;
 143
 144     case _CS_XBS5_ILP32_OFF32_LDFLAGS:
 145     case _CS_POSIX_V6_ILP32_OFF32_LDFLAGS:
 146     case _CS_POSIX_V7_ILP32_OFF32_LDFLAGS:
 147 #ifdef __ILP32_OFF32_LDFLAGS
 148 # if CONF_IS_DEFINED_UNSET (_POSIX_V7_ILP32_OFF32 )
 149 #  error "__ILP32_OFF32_LDFLAGS should not be defined"
 150 # elif CONF_IS_UNDEFINED (_POSIX_V7_ILP32_OFF32)
 151       if (__sysconf (_SC_V7_ILP32_OFF32) < 0)
 152         break;
 153 # endif
 154       string = __ILP32_OFF32_LDFLAGS;
 155       string_len = sizeof (__ILP32_OFF32_LDFLAGS);
 156 #endif
 157       break;
 158
 159     case _CS_XBS5_ILP32_OFFBIG_LDFLAGS:
 160     case _CS_POSIX_V6_ILP32_OFFBIG_LDFLAGS:
 161     case _CS_POSIX_V7_ILP32_OFFBIG_LDFLAGS:
 162 #ifdef __ILP32_OFFBIG_LDFLAGS
 163 # if CONF_IS_DEFINED_UNSET (_POSIX_V7_ILP32_OFFBIG)
 164 #  error "__ILP32_OFFBIG_LDFLAGS should not be defined"
 165 # elif CONF_IS_UNDEFINED (_POSIX_V7_ILP32_OFFBIG)
 166       if (__sysconf (_SC_V7_ILP32_OFFBIG) < 0)
 167         break;
 168 # endif
 169       string = __ILP32_OFFBIG_LDFLAGS;
 170       string_len = sizeof (__ILP32_OFFBIG_LDFLAGS);
 171 #endif
 172       break;
 173
 174     case _CS_XBS5_LP64_OFF64_LDFLAGS:
 175     case _CS_POSIX_V6_LP64_OFF64_LDFLAGS:
 176     case _CS_POSIX_V7_LP64_OFF64_LDFLAGS:
 177 #ifdef __LP64_OFF64_LDFLAGS
 178 # if CONF_IS_DEFINED_UNSET (_POSIX_V7_LP64_OFF64)
 179 #  error "__LP64_OFF64_LDFLAGS should not be defined"
 180 # elif CONF_IS_UNDEFINED (_POSIX_V7_LP64_OFF64)
 181       if (__sysconf (_SC_V7_LP64_OFF64) < 0)
 182         break;
 183 # endif
 184       string = __LP64_OFF64_LDFLAGS;
 185       string_len = sizeof (__LP64_OFF64_LDFLAGS);
 186 #endif
 187       break;
 188
 189     case _CS_LFS_CFLAGS:
 190     case _CS_LFS_LINTFLAGS:
 191 #if (CONF_IS_DEFINED_SET (_POSIX_V6_ILP32_OFF32) \
 192      && CONF_IS_DEFINED_SET (_POSIX_V6_ILP32_OFFBIG))
 193 # define __LFS_CFLAGS "-D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64"
 194       /* Signal that we want the new ABI.  */
 195       string = __LFS_CFLAGS;
 196       string_len = sizeof (__LFS_CFLAGS);
 197 #endif
 198       break;
 199
 200     case _CS_LFS_LDFLAGS:
 201     case _CS_LFS_LIBS:
 202       /* No special libraries or linker flags needed.  */
 203       break;
 204
 205     case _CS_LFS64_CFLAGS:
 206     case _CS_LFS64_LINTFLAGS:
 207 #define __LFS64_CFLAGS "-D_LARGEFILE64_SOURCE"
 208       string = __LFS64_CFLAGS;
 209       string_len = sizeof (__LFS64_CFLAGS);
 210       break;
 211
 212     case _CS_LFS64_LDFLAGS:
 213     case _CS_LFS64_LIBS:
 214       /* No special libraries or linker flags needed.  */
 215       break;
 216
 217     case _CS_XBS5_ILP32_OFF32_LIBS:
 218     case _CS_XBS5_ILP32_OFF32_LINTFLAGS:
 219     case _CS_XBS5_ILP32_OFFBIG_LIBS:
 220     case _CS_XBS5_ILP32_OFFBIG_LINTFLAGS:
 221     case _CS_XBS5_LP64_OFF64_LIBS:
 222     case _CS_XBS5_LP64_OFF64_LINTFLAGS:
 223     case _CS_XBS5_LPBIG_OFFBIG_CFLAGS:
 224     case _CS_XBS5_LPBIG_OFFBIG_LDFLAGS:
 225     case _CS_XBS5_LPBIG_OFFBIG_LIBS:
 226     case _CS_XBS5_LPBIG_OFFBIG_LINTFLAGS:
 227
 228     case _CS_POSIX_V6_ILP32_OFF32_LIBS:
 229     case _CS_POSIX_V6_ILP32_OFF32_LINTFLAGS:
 230     case _CS_POSIX_V6_ILP32_OFFBIG_LIBS:
 231     case _CS_POSIX_V6_ILP32_OFFBIG_LINTFLAGS:
 232     case _CS_POSIX_V6_LP64_OFF64_LIBS:
 233     case _CS_POSIX_V6_LP64_OFF64_LINTFLAGS:
 234     case _CS_POSIX_V6_LPBIG_OFFBIG_CFLAGS:
 235     case _CS_POSIX_V6_LPBIG_OFFBIG_LDFLAGS:
 236     case _CS_POSIX_V6_LPBIG_OFFBIG_LIBS:
 237     case _CS_POSIX_V6_LPBIG_OFFBIG_LINTFLAGS:
 238
 239     case _CS_POSIX_V7_ILP32_OFF32_LIBS:
 240     case _CS_POSIX_V7_ILP32_OFF32_LINTFLAGS:
 241     case _CS_POSIX_V7_ILP32_OFFBIG_LIBS:
 242     case _CS_POSIX_V7_ILP32_OFFBIG_LINTFLAGS:
 243     case _CS_POSIX_V7_LP64_OFF64_LIBS:
 244     case _CS_POSIX_V7_LP64_OFF64_LINTFLAGS:
 245     case _CS_POSIX_V7_LPBIG_OFFBIG_CFLAGS:
 246     case _CS_POSIX_V7_LPBIG_OFFBIG_LDFLAGS:
 247     case _CS_POSIX_V7_LPBIG_OFFBIG_LIBS:
 248     case _CS_POSIX_V7_LPBIG_OFFBIG_LINTFLAGS:
 249       /* GNU libc does not require special actions to use LFS functions.  */
 250       break;
 251
 252     case _CS_GNU_LIBC_VERSION:
 253       string = "glibc " VERSION;
 254       string_len = sizeof ("glibc " VERSION);
 255       break;
 256
 257     case _CS_GNU_LIBPTHREAD_VERSION:
 258 #ifdef LIBPTHREAD_VERSION
 259       string = LIBPTHREAD_VERSION;
 260       string_len = sizeof LIBPTHREAD_VERSION;
 261       break;
 262 #else
 263       /* No thread library.  */
 264       __set_errno (EINVAL);
 265       return 0;
 266 #endif
 267
 268     case _CS_V6_ENV:
 269     case _CS_V7_ENV:
 270       /* Maybe something else is needed in future.  */
 271       string = "POSIXLY_CORRECT=1";
 272       string_len = sizeof ("POSIXLY_CORRECT=1");
 273       break;
 274
 275     default:
 276       __set_errno (EINVAL);
 277       return 0;
 278     }
 279
 280   if (len > 0 && buf != NULL)
 281     {
 282       if (string_len <= len)
 283         memcpy (buf, string, string_len);
 284       else
 285         {
 286           memcpy (buf, string, len - 1);
 287           buf[len - 1] = '\0';
 288         }
 289     }
 290   return string_len;
 291 }
 292 libc_hidden_def (confstr)