lib/strerror_r.c

   1 /* strerror_r.c --- POSIX compatible system error routine
   2
   3    Copyright (C) 2010-2024 Free Software Foundation, Inc.
   4
   5    This file is free software: you can redistribute it and/or modify
   6    it under the terms of the GNU Lesser General Public License as
   7    published by the Free Software Foundation; either version 2.1 of the
   8    License, or (at your option) any later version.
   9
  10    This file 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 Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser 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 STRERROR_R_CHAR_P
  38
  39 # if HAVE___XPG_STRERROR_R
  40 _GL_EXTERN_C int __xpg_strerror_r (int errnum, char *buf, size_t buflen);
  41 # endif
  42
  43 #elif HAVE_DECL_STRERROR_R
  44
  45 /* The system's strerror_r function's API is OK, except that its third argument
  46    is 'int', not 'size_t', or its return type is wrong.  */
  47
  48 # include <limits.h>
  49
  50 #else
  51
  52 /* Use the system's strerror().  Exclude glibc and cygwin because the
  53    system strerror_r has the wrong return type, and cygwin 1.7.9
  54    strerror_r clobbers strerror.  */
  55 # undef strerror
  56
  57 # if defined __NetBSD__ || defined __hpux || (defined _WIN32 && !defined __CYGWIN__) || defined __sgi || (defined __sun && !defined _LP64) || defined __CYGWIN__
  58
  59 /* No locking needed.  */
  60
  61 /* Get catgets internationalization functions.  */
  62 #  if HAVE_CATGETS
  63 #   include <nl_types.h>
  64 #  endif
  65
  66 #ifdef __cplusplus
  67 extern "C" {
  68 #endif
  69
  70 /* Get sys_nerr, sys_errlist on HP-UX (otherwise only declared in C++ mode).
  71    Get sys_nerr, sys_errlist on IRIX (otherwise only declared with _SGIAPI).  */
  72 #  if defined __hpux || defined __sgi
  73 extern int sys_nerr;
  74 extern char *sys_errlist[];
  75 #  endif
  76
  77 /* Get sys_nerr on Solaris.  */
  78 #  if defined __sun && !defined _LP64
  79 extern int sys_nerr;
  80 #  endif
  81
  82 #ifdef __cplusplus
  83 }
  84 #endif
  85
  86 # else
  87
  88 #  include "glthread/lock.h"
  89
  90 /* This lock protects the buffer returned by strerror().  We assume that
  91    no other uses of strerror() exist in the program.  */
  92 gl_lock_define_initialized(static, strerror_lock)
  93
  94 # endif
  95
  96 #endif
  97
  98 /* On MSVC, there is no snprintf() function, just a _snprintf().
  99    It is of lower quality, but sufficient for the simple use here.
 100    We only have to make sure to NUL terminate the result (_snprintf
 101    does not NUL terminate, like strncpy).  */
 102 #if !HAVE_SNPRINTF
 103 static int
 104 local_snprintf (char *buf, size_t buflen, const char *format, ...)
 105 {
 106   va_list args;
 107   int result;
 108
 109   va_start (args, format);
 110   result = _vsnprintf (buf, buflen, format, args);
 111   va_end (args);
 112   if (buflen > 0 && (result < 0 || result >= buflen))
 113     buf[buflen - 1] = '\0';
 114   return result;
 115 }
 116 # undef snprintf
 117 # define snprintf local_snprintf
 118 #endif
 119
 120 /* Copy as much of MSG into BUF as possible, without corrupting errno.
 121    Return 0 if MSG fit in BUFLEN, otherwise return ERANGE.  */
 122 static int
 123 safe_copy (char *buf, size_t buflen, const char *msg)
 124 {
 125   size_t len = strlen (msg);
 126   size_t moved = len < buflen ? len : buflen - 1;
 127
 128   /* Although POSIX lets memmove corrupt errno, we don't
 129      know of any implementation where this is a real problem.  */
 130   memmove (buf, msg, moved);
 131   buf[moved] = '\0';
 132   return len < buflen ? 0 : ERANGE;
 133 }
 134
 135
 136 int
 137 strerror_r (int errnum, char *buf, size_t buflen)
 138 #undef strerror_r
 139 {
 140   /* Filter this out now, so that rest of this replacement knows that
 141      there is room for a non-empty message and trailing NUL.  */
 142   if (buflen <= 1)
 143     {
 144       if (buflen)
 145         *buf = '\0';
 146       return ERANGE;
 147     }
 148   *buf = '\0';
 149
 150   /* Check for gnulib overrides.  */
 151   {
 152     char const *msg = strerror_override (errnum);
 153
 154     if (msg)
 155       return safe_copy (buf, buflen, msg);
 156   }
 157
 158   {
 159     int ret;
 160     int saved_errno = errno;
 161
 162 #if STRERROR_R_CHAR_P
 163
 164     {
 165       ret = 0;
 166
 167 # if HAVE___XPG_STRERROR_R
 168       ret = __xpg_strerror_r (errnum, buf, buflen);
 169       /* ret is 0 upon success, or EINVAL or ERANGE upon failure.  */
 170 # endif
 171
 172       if (!*buf)
 173         {
 174           /* glibc 2.13 ... 2.34 (at least) don't touch buf upon failure.
 175              Therefore we have to fall back to strerror_r which, for valid
 176              errnum, returns a thread-safe untruncated string.  For invalid
 177              errnum, though, it returns a truncated string, which does not
 178              allow us to determine whether to return ERANGE or 0.  Thus we
 179              need to pass a sufficiently large buffer.  */
 180           char stackbuf[80];
 181           char *errstring = strerror_r (errnum, stackbuf, sizeof stackbuf);
 182           ret = errstring ? safe_copy (buf, buflen, errstring) : errno;
 183         }
 184     }
 185
 186 #elif HAVE_DECL_STRERROR_R
 187
 188     if (buflen > INT_MAX)
 189       buflen = INT_MAX;
 190
 191 # ifdef __hpux
 192     /* On HP-UX 11.31, strerror_r always fails when buflen < 80; it
 193        also fails to change buf on EINVAL.  */
 194     {
 195       char stackbuf[80];
 196
 197       if (buflen < sizeof stackbuf)
 198         {
 199           ret = strerror_r (errnum, stackbuf, sizeof stackbuf);
 200           if (ret == 0)
 201             ret = safe_copy (buf, buflen, stackbuf);
 202         }
 203       else
 204         ret = strerror_r (errnum, buf, buflen);
 205     }
 206 # else
 207     ret = strerror_r (errnum, buf, buflen);
 208
 209     /* Some old implementations may return (-1, EINVAL) instead of EINVAL.
 210        But on Haiku, valid error numbers are negative.  */
 211 #  if !defined __HAIKU__
 212     if (ret < 0)
 213       ret = errno;
 214 #  endif
 215 # endif
 216
 217 # if defined _AIX || defined __HAIKU__
 218     /* AIX and Haiku return 0 rather than ERANGE when truncating strings; try
 219        again until we are sure we got the entire string.  */
 220     if (!ret && strlen (buf) == buflen - 1)
 221       {
 222         char stackbuf[STACKBUF_LEN];
 223         size_t len;
 224         strerror_r (errnum, stackbuf, sizeof stackbuf);
 225         len = strlen (stackbuf);
 226         /* STACKBUF_LEN should have been large enough.  */
 227         if (len + 1 == sizeof stackbuf)
 228           abort ();
 229         if (buflen <= len)
 230           ret = ERANGE;
 231       }
 232 # else
 233     /* Solaris 10 does not populate buf on ERANGE.  OpenBSD 4.7
 234        truncates early on ERANGE rather than return a partial integer.
 235        We prefer the maximal string.  We set buf[0] earlier, and we
 236        know of no implementation that modifies buf to be an
 237        unterminated string, so this strlen should be portable in
 238        practice (rather than pulling in a safer strnlen).  */
 239     if (ret == ERANGE && strlen (buf) < buflen - 1)
 240       {
 241         char stackbuf[STACKBUF_LEN];
 242
 243         /* STACKBUF_LEN should have been large enough.  */
 244         if (strerror_r (errnum, stackbuf, sizeof stackbuf) == ERANGE)
 245           abort ();
 246         safe_copy (buf, buflen, stackbuf);
 247       }
 248 # endif
 249
 250 #else /* strerror_r is not declared.  */
 251
 252     /* Try to do what strerror (errnum) does, but without clobbering the
 253        buffer used by strerror().  */
 254
 255 # if defined __NetBSD__ || defined __hpux || (defined _WIN32 && !defined __CYGWIN__) || defined __CYGWIN__ /* NetBSD, HP-UX, native Windows, Cygwin */
 256
 257     /* NetBSD:         sys_nerr, sys_errlist are declared through _NETBSD_SOURCE
 258                        and <errno.h> above.
 259        HP-UX:          sys_nerr, sys_errlist are declared explicitly above.
 260        native Windows: sys_nerr, sys_errlist are declared in <stdlib.h>.
 261        Cygwin:         sys_nerr, sys_errlist are declared in <errno.h>.  */
 262     if (errnum >= 0 && errnum < sys_nerr)
 263       {
 264 #  if HAVE_CATGETS && (defined __NetBSD__ || defined __hpux)
 265 #   if defined __NetBSD__
 266         nl_catd catd = catopen ("libc", NL_CAT_LOCALE);
 267         const char *errmsg =
 268           (catd != (nl_catd)-1
 269            ? catgets (catd, 1, errnum, sys_errlist[errnum])
 270            : sys_errlist[errnum]);
 271 #   endif
 272 #   if defined __hpux
 273         nl_catd catd = catopen ("perror", NL_CAT_LOCALE);
 274         const char *errmsg =
 275           (catd != (nl_catd)-1
 276            ? catgets (catd, 1, 1 + errnum, sys_errlist[errnum])
 277            : sys_errlist[errnum]);
 278 #   endif
 279 #  else
 280         const char *errmsg = sys_errlist[errnum];
 281 #  endif
 282         if (errmsg == NULL || *errmsg == '\0')
 283           ret = EINVAL;
 284         else
 285           ret = safe_copy (buf, buflen, errmsg);
 286 #  if HAVE_CATGETS && (defined __NetBSD__ || defined __hpux)
 287         if (catd != (nl_catd)-1)
 288           catclose (catd);
 289 #  endif
 290       }
 291     else
 292       ret = EINVAL;
 293
 294 # elif defined __sgi || (defined __sun && !defined _LP64) /* IRIX, Solaris <= 9 32-bit */
 295
 296     /* For a valid error number, the system's strerror() function returns
 297        a pointer to a not copied string, not to a buffer.  */
 298     if (errnum >= 0 && errnum < sys_nerr)
 299       {
 300         char *errmsg = strerror (errnum);
 301
 302         if (errmsg == NULL || *errmsg == '\0')
 303           ret = EINVAL;
 304         else
 305           ret = safe_copy (buf, buflen, errmsg);
 306       }
 307     else
 308       ret = EINVAL;
 309
 310 # else
 311
 312     gl_lock_lock (strerror_lock);
 313
 314     {
 315       char *errmsg = strerror (errnum);
 316
 317       /* For invalid error numbers, strerror() on
 318            - IRIX 6.5 returns NULL,
 319            - HP-UX 11 returns an empty string.  */
 320       if (errmsg == NULL || *errmsg == '\0')
 321         ret = EINVAL;
 322       else
 323         ret = safe_copy (buf, buflen, errmsg);
 324     }
 325
 326     gl_lock_unlock (strerror_lock);
 327
 328 # endif
 329
 330 #endif
 331
 332 #if defined _WIN32 && !defined __CYGWIN__
 333     /* MSVC 14 defines names for many error codes in the range 100..140,
 334        but _sys_errlist contains strings only for the error codes
 335        < _sys_nerr = 43.  */
 336     if (ret == EINVAL)
 337       {
 338         const char *errmsg;
 339
 340         switch (errnum)
 341           {
 342           case 100 /* EADDRINUSE */:
 343             errmsg = "Address already in use";
 344             break;
 345           case 101 /* EADDRNOTAVAIL */:
 346             errmsg = "Cannot assign requested address";
 347             break;
 348           case 102 /* EAFNOSUPPORT */:
 349             errmsg = "Address family not supported by protocol";
 350             break;
 351           case 103 /* EALREADY */:
 352             errmsg = "Operation already in progress";
 353             break;
 354           case 105 /* ECANCELED */:
 355             errmsg = "Operation canceled";
 356             break;
 357           case 106 /* ECONNABORTED */:
 358             errmsg = "Software caused connection abort";
 359             break;
 360           case 107 /* ECONNREFUSED */:
 361             errmsg = "Connection refused";
 362             break;
 363           case 108 /* ECONNRESET */:
 364             errmsg = "Connection reset by peer";
 365             break;
 366           case 109 /* EDESTADDRREQ */:
 367             errmsg = "Destination address required";
 368             break;
 369           case 110 /* EHOSTUNREACH */:
 370             errmsg = "No route to host";
 371             break;
 372           case 112 /* EINPROGRESS */:
 373             errmsg = "Operation now in progress";
 374             break;
 375           case 113 /* EISCONN */:
 376             errmsg = "Transport endpoint is already connected";
 377             break;
 378           case 114 /* ELOOP */:
 379             errmsg = "Too many levels of symbolic links";
 380             break;
 381           case 115 /* EMSGSIZE */:
 382             errmsg = "Message too long";
 383             break;
 384           case 116 /* ENETDOWN */:
 385             errmsg = "Network is down";
 386             break;
 387           case 117 /* ENETRESET */:
 388             errmsg = "Network dropped connection on reset";
 389             break;
 390           case 118 /* ENETUNREACH */:
 391             errmsg = "Network is unreachable";
 392             break;
 393           case 119 /* ENOBUFS */:
 394             errmsg = "No buffer space available";
 395             break;
 396           case 123 /* ENOPROTOOPT */:
 397             errmsg = "Protocol not available";
 398             break;
 399           case 126 /* ENOTCONN */:
 400             errmsg = "Transport endpoint is not connected";
 401             break;
 402           case 128 /* ENOTSOCK */:
 403             errmsg = "Socket operation on non-socket";
 404             break;
 405           case 129 /* ENOTSUP */:
 406             errmsg = "Not supported";
 407             break;
 408           case 130 /* EOPNOTSUPP */:
 409             errmsg = "Operation not supported";
 410             break;
 411           case 132 /* EOVERFLOW */:
 412             errmsg = "Value too large for defined data type";
 413             break;
 414           case 133 /* EOWNERDEAD */:
 415             errmsg = "Owner died";
 416             break;
 417           case 134 /* EPROTO */:
 418             errmsg = "Protocol error";
 419             break;
 420           case 135 /* EPROTONOSUPPORT */:
 421             errmsg = "Protocol not supported";
 422             break;
 423           case 136 /* EPROTOTYPE */:
 424             errmsg = "Protocol wrong type for socket";
 425             break;
 426           case 138 /* ETIMEDOUT */:
 427             errmsg = "Connection timed out";
 428             break;
 429           case 140 /* EWOULDBLOCK */:
 430             errmsg = "Operation would block";
 431             break;
 432           default:
 433             errmsg = NULL;
 434             break;
 435           }
 436         if (errmsg != NULL)
 437           ret = safe_copy (buf, buflen, errmsg);
 438       }
 439 #endif
 440
 441     if (ret == EINVAL && !*buf)
 442       {
 443 #if defined __HAIKU__
 444         /* For consistency with perror().  */
 445         snprintf (buf, buflen, "Unknown Application Error (%d)", errnum);
 446 #else
 447         snprintf (buf, buflen, "Unknown error %d", errnum);
 448 #endif
 449       }
 450
 451     errno = saved_errno;
 452     return ret;
 453   }
 454 }