lib/strerror_r.c

   1 /* strerror_r.c --- POSIX compatible system error routine
   2
   3    Copyright (C) 2010-2020 Free Software Foundation, Inc.
   4
   5    This program is free software: you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  17
  18 /* Written by Bruno Haible <bruno@clisp.org>, 2010.  */
  19
  20 #include <config.h>
  21
  22 /* Enable declaration of sys_nerr and sys_errlist in <errno.h> on NetBSD.  */
  23 #define _NETBSD_SOURCE 1
  24
  25 /* Specification.  */
  26 #include <string.h>
  27
  28 #include <errno.h>
  29 #include <stdio.h>
  30 #include <stdlib.h>
  31 #if !HAVE_SNPRINTF
  32 # include <stdarg.h>
  33 #endif
  34
  35 #include "strerror-override.h"
  36
  37 #if (__GLIBC__ >= 2 || defined __UCLIBC__ || defined __CYGWIN__) && HAVE___XPG_STRERROR_R /* glibc >= 2.3.4, cygwin >= 1.7.9 */
  38
  39 # define USE_XPG_STRERROR_R 1
  40 extern
  41 #ifdef __cplusplus
  42 "C"
  43 #endif
  44 int __xpg_strerror_r (int errnum, char *buf, size_t buflen);
  45
  46 #elif HAVE_DECL_STRERROR_R && !(__GLIBC__ >= 2 || defined __UCLIBC__ || defined __CYGWIN__)
  47
  48 /* The system's strerror_r function is OK, except that its third argument
  49    is 'int', not 'size_t', or its return type is wrong.  */
  50
  51 # include <limits.h>
  52
  53 # define USE_SYSTEM_STRERROR_R 1
  54
  55 #else /* (__GLIBC__ >= 2 || defined __UCLIBC__ || defined __CYGWIN__ ? !HAVE___XPG_STRERROR_R : !HAVE_DECL_STRERROR_R) */
  56
  57 /* Use the system's strerror().  Exclude glibc and cygwin because the
  58    system strerror_r has the wrong return type, and cygwin 1.7.9
  59    strerror_r clobbers strerror.  */
  60 # undef strerror
  61
  62 # define USE_SYSTEM_STRERROR 1
  63
  64 # if defined __NetBSD__ || defined __hpux || (defined _WIN32 && !defined __CYGWIN__) || defined __sgi || (defined __sun && !defined _LP64) || defined __CYGWIN__
  65
  66 /* No locking needed.  */
  67
  68 /* Get catgets internationalization functions.  */
  69 #  if HAVE_CATGETS
  70 #   include <nl_types.h>
  71 #  endif
  72
  73 #ifdef __cplusplus
  74 extern "C" {
  75 #endif
  76
  77 /* Get sys_nerr, sys_errlist on HP-UX (otherwise only declared in C++ mode).
  78    Get sys_nerr, sys_errlist on IRIX (otherwise only declared with _SGIAPI).  */
  79 #  if defined __hpux || defined __sgi
  80 extern int sys_nerr;
  81 extern char *sys_errlist[];
  82 #  endif
  83
  84 /* Get sys_nerr on Solaris.  */
  85 #  if defined __sun && !defined _LP64
  86 extern int sys_nerr;
  87 #  endif
  88
  89 #ifdef __cplusplus
  90 }
  91 #endif
  92
  93 # else
  94
  95 #  include "glthread/lock.h"
  96
  97 /* This lock protects the buffer returned by strerror().  We assume that
  98    no other uses of strerror() exist in the program.  */
  99 gl_lock_define_initialized(static, strerror_lock)
 100
 101 # endif
 102
 103 #endif
 104
 105 /* On MSVC, there is no snprintf() function, just a _snprintf().
 106    It is of lower quality, but sufficient for the simple use here.
 107    We only have to make sure to NUL terminate the result (_snprintf
 108    does not NUL terminate, like strncpy).  */
 109 #if !HAVE_SNPRINTF
 110 static int
 111 local_snprintf (char *buf, size_t buflen, const char *format, ...)
 112 {
 113   va_list args;
 114   int result;
 115
 116   va_start (args, format);
 117   result = _vsnprintf (buf, buflen, format, args);
 118   va_end (args);
 119   if (buflen > 0 && (result < 0 || result >= buflen))
 120     buf[buflen - 1] = '\0';
 121   return result;
 122 }
 123 # undef snprintf
 124 # define snprintf local_snprintf
 125 #endif
 126
 127 /* Copy as much of MSG into BUF as possible, without corrupting errno.
 128    Return 0 if MSG fit in BUFLEN, otherwise return ERANGE.  */
 129 static int
 130 safe_copy (char *buf, size_t buflen, const char *msg)
 131 {
 132   size_t len = strlen (msg);
 133   size_t moved = len < buflen ? len : buflen - 1;
 134
 135   /* Although POSIX lets memmove corrupt errno, we don't
 136      know of any implementation where this is a real problem.  */
 137   memmove (buf, msg, moved);
 138   buf[moved] = '\0';
 139   return len < buflen ? 0 : ERANGE;
 140 }
 141
 142
 143 int
 144 strerror_r (int errnum, char *buf, size_t buflen)
 145 #undef strerror_r
 146 {
 147   /* Filter this out now, so that rest of this replacement knows that
 148      there is room for a non-empty message and trailing NUL.  */
 149   if (buflen <= 1)
 150     {
 151       if (buflen)
 152         *buf = '\0';
 153       return ERANGE;
 154     }
 155   *buf = '\0';
 156
 157   /* Check for gnulib overrides.  */
 158   {
 159     char const *msg = strerror_override (errnum);
 160
 161     if (msg)
 162       return safe_copy (buf, buflen, msg);
 163   }
 164
 165   {
 166     int ret;
 167     int saved_errno = errno;
 168
 169 #if USE_XPG_STRERROR_R
 170
 171     {
 172       ret = __xpg_strerror_r (errnum, buf, buflen);
 173       if (ret < 0)
 174         ret = errno;
 175       if (!*buf)
 176         {
 177           /* glibc 2.13 would not touch buf on err, so we have to fall
 178              back to GNU strerror_r which always returns a thread-safe
 179              untruncated string to (partially) copy into our buf.  */
 180           safe_copy (buf, buflen, strerror_r (errnum, buf, buflen));
 181         }
 182     }
 183
 184 #elif USE_SYSTEM_STRERROR_R
 185
 186     if (buflen > INT_MAX)
 187       buflen = INT_MAX;
 188
 189 # ifdef __hpux
 190     /* On HP-UX 11.31, strerror_r always fails when buflen < 80; it
 191        also fails to change buf on EINVAL.  */
 192     {
 193       char stackbuf[80];
 194
 195       if (buflen < sizeof stackbuf)
 196         {
 197           ret = strerror_r (errnum, stackbuf, sizeof stackbuf);
 198           if (ret == 0)
 199             ret = safe_copy (buf, buflen, stackbuf);
 200         }
 201       else
 202         ret = strerror_r (errnum, buf, buflen);
 203     }
 204 # else
 205     ret = strerror_r (errnum, buf, buflen);
 206
 207     /* Some old implementations may return (-1, EINVAL) instead of EINVAL.
 208        But on Haiku, valid error numbers are negative.  */
 209 #  if !defined __HAIKU__
 210     if (ret < 0)
 211       ret = errno;
 212 #  endif
 213 # endif
 214
 215 # if defined _AIX || defined __HAIKU__
 216     /* AIX and Haiku return 0 rather than ERANGE when truncating strings; try
 217        again until we are sure we got the entire string.  */
 218     if (!ret && strlen (buf) == buflen - 1)
 219       {
 220         char stackbuf[STACKBUF_LEN];
 221         size_t len;
 222         strerror_r (errnum, stackbuf, sizeof stackbuf);
 223         len = strlen (stackbuf);
 224         /* STACKBUF_LEN should have been large enough.  */
 225         if (len + 1 == sizeof stackbuf)
 226           abort ();
 227         if (buflen <= len)
 228           ret = ERANGE;
 229       }
 230 # else
 231     /* Solaris 10 does not populate buf on ERANGE.  OpenBSD 4.7
 232        truncates early on ERANGE rather than return a partial integer.
 233        We prefer the maximal string.  We set buf[0] earlier, and we
 234        know of no implementation that modifies buf to be an
 235        unterminated string, so this strlen should be portable in
 236        practice (rather than pulling in a safer strnlen).  */
 237     if (ret == ERANGE && strlen (buf) < buflen - 1)
 238       {
 239         char stackbuf[STACKBUF_LEN];
 240
 241         /* STACKBUF_LEN should have been large enough.  */
 242         if (strerror_r (errnum, stackbuf, sizeof stackbuf) == ERANGE)
 243           abort ();
 244         safe_copy (buf, buflen, stackbuf);
 245       }
 246 # endif
 247
 248 #else /* USE_SYSTEM_STRERROR */
 249
 250     /* Try to do what strerror (errnum) does, but without clobbering the
 251        buffer used by strerror().  */
 252
 253 # if defined __NetBSD__ || defined __hpux || (defined _WIN32 && !defined __CYGWIN__) || defined __CYGWIN__ /* NetBSD, HP-UX, native Windows, Cygwin */
 254
 255     /* NetBSD:         sys_nerr, sys_errlist are declared through _NETBSD_SOURCE
 256                        and <errno.h> above.
 257        HP-UX:          sys_nerr, sys_errlist are declared explicitly above.
 258        native Windows: sys_nerr, sys_errlist are declared in <stdlib.h>.
 259        Cygwin:         sys_nerr, sys_errlist are declared in <errno.h>.  */
 260     if (errnum >= 0 && errnum < sys_nerr)
 261       {
 262 #  if HAVE_CATGETS && (defined __NetBSD__ || defined __hpux)
 263 #   if defined __NetBSD__
 264         nl_catd catd = catopen ("libc", NL_CAT_LOCALE);
 265         const char *errmsg =
 266           (catd != (nl_catd)-1
 267            ? catgets (catd, 1, errnum, sys_errlist[errnum])
 268            : sys_errlist[errnum]);
 269 #   endif
 270 #   if defined __hpux
 271         nl_catd catd = catopen ("perror", NL_CAT_LOCALE);
 272         const char *errmsg =
 273           (catd != (nl_catd)-1
 274            ? catgets (catd, 1, 1 + errnum, sys_errlist[errnum])
 275            : sys_errlist[errnum]);
 276 #   endif
 277 #  else
 278         const char *errmsg = sys_errlist[errnum];
 279 #  endif
 280         if (errmsg == NULL || *errmsg == '\0')
 281           ret = EINVAL;
 282         else
 283           ret = safe_copy (buf, buflen, errmsg);
 284 #  if HAVE_CATGETS && (defined __NetBSD__ || defined __hpux)
 285         if (catd != (nl_catd)-1)
 286           catclose (catd);
 287 #  endif
 288       }
 289     else
 290       ret = EINVAL;
 291
 292 # elif defined __sgi || (defined __sun && !defined _LP64) /* IRIX, Solaris <= 9 32-bit */
 293
 294     /* For a valid error number, the system's strerror() function returns
 295        a pointer to a not copied string, not to a buffer.  */
 296     if (errnum >= 0 && errnum < sys_nerr)
 297       {
 298         char *errmsg = strerror (errnum);
 299
 300         if (errmsg == NULL || *errmsg == '\0')
 301           ret = EINVAL;
 302         else
 303           ret = safe_copy (buf, buflen, errmsg);
 304       }
 305     else
 306       ret = EINVAL;
 307
 308 # else
 309
 310     gl_lock_lock (strerror_lock);
 311
 312     {
 313       char *errmsg = strerror (errnum);
 314
 315       /* For invalid error numbers, strerror() on
 316            - IRIX 6.5 returns NULL,
 317            - HP-UX 11 returns an empty string.  */
 318       if (errmsg == NULL || *errmsg == '\0')
 319         ret = EINVAL;
 320       else
 321         ret = safe_copy (buf, buflen, errmsg);
 322     }
 323
 324     gl_lock_unlock (strerror_lock);
 325
 326 # endif
 327
 328 #endif
 329
 330 #if defined _WIN32 && !defined __CYGWIN__
 331     /* MSVC 14 defines names for many error codes in the range 100..140,
 332        but _sys_errlist contains strings only for the error codes
 333        < _sys_nerr = 43.  */
 334     if (ret == EINVAL)
 335       {
 336         const char *errmsg;
 337
 338         switch (errnum)
 339           {
 340           case 100 /* EADDRINUSE */:
 341             errmsg = "Address already in use";
 342             break;
 343           case 101 /* EADDRNOTAVAIL */:
 344             errmsg = "Cannot assign requested address";
 345             break;
 346           case 102 /* EAFNOSUPPORT */:
 347             errmsg = "Address family not supported by protocol";
 348             break;
 349           case 103 /* EALREADY */:
 350             errmsg = "Operation already in progress";
 351             break;
 352           case 105 /* ECANCELED */:
 353             errmsg = "Operation canceled";
 354             break;
 355           case 106 /* ECONNABORTED */:
 356             errmsg = "Software caused connection abort";
 357             break;
 358           case 107 /* ECONNREFUSED */:
 359             errmsg = "Connection refused";
 360             break;
 361           case 108 /* ECONNRESET */:
 362             errmsg = "Connection reset by peer";
 363             break;
 364           case 109 /* EDESTADDRREQ */:
 365             errmsg = "Destination address required";
 366             break;
 367           case 110 /* EHOSTUNREACH */:
 368             errmsg = "No route to host";
 369             break;
 370           case 112 /* EINPROGRESS */:
 371             errmsg = "Operation now in progress";
 372             break;
 373           case 113 /* EISCONN */:
 374             errmsg = "Transport endpoint is already connected";
 375             break;
 376           case 114 /* ELOOP */:
 377             errmsg = "Too many levels of symbolic links";
 378             break;
 379           case 115 /* EMSGSIZE */:
 380             errmsg = "Message too long";
 381             break;
 382           case 116 /* ENETDOWN */:
 383             errmsg = "Network is down";
 384             break;
 385           case 117 /* ENETRESET */:
 386             errmsg = "Network dropped connection on reset";
 387             break;
 388           case 118 /* ENETUNREACH */:
 389             errmsg = "Network is unreachable";
 390             break;
 391           case 119 /* ENOBUFS */:
 392             errmsg = "No buffer space available";
 393             break;
 394           case 123 /* ENOPROTOOPT */:
 395             errmsg = "Protocol not available";
 396             break;
 397           case 126 /* ENOTCONN */:
 398             errmsg = "Transport endpoint is not connected";
 399             break;
 400           case 128 /* ENOTSOCK */:
 401             errmsg = "Socket operation on non-socket";
 402             break;
 403           case 129 /* ENOTSUP */:
 404             errmsg = "Not supported";
 405             break;
 406           case 130 /* EOPNOTSUPP */:
 407             errmsg = "Operation not supported";
 408             break;
 409           case 132 /* EOVERFLOW */:
 410             errmsg = "Value too large for defined data type";
 411             break;
 412           case 133 /* EOWNERDEAD */:
 413             errmsg = "Owner died";
 414             break;
 415           case 134 /* EPROTO */:
 416             errmsg = "Protocol error";
 417             break;
 418           case 135 /* EPROTONOSUPPORT */:
 419             errmsg = "Protocol not supported";
 420             break;
 421           case 136 /* EPROTOTYPE */:
 422             errmsg = "Protocol wrong type for socket";
 423             break;
 424           case 138 /* ETIMEDOUT */:
 425             errmsg = "Connection timed out";
 426             break;
 427           case 140 /* EWOULDBLOCK */:
 428             errmsg = "Operation would block";
 429             break;
 430           default:
 431             errmsg = NULL;
 432             break;
 433           }
 434         if (errmsg != NULL)
 435           ret = safe_copy (buf, buflen, errmsg);
 436       }
 437 #endif
 438
 439     if (ret == EINVAL && !*buf)
 440       {
 441 #if defined __HAIKU__
 442         /* For consistency with perror().  */
 443         snprintf (buf, buflen, "Unknown Application Error (%d)", errnum);
 444 #else
 445         snprintf (buf, buflen, "Unknown error %d", errnum);
 446 #endif
 447       }
 448
 449     errno = saved_errno;
 450     return ret;
 451   }
 452 }