kc3-lang/gnulib/lib/strerror.c

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• Hash : c7487319
  Author :
  Date : 2011-06-21T08:50:51
  

  strerror_r: fix OpenBSD behavior on 0
  
  OpenBSD treats strerror_r(0,,) as a success, but with a message
  "Undefined error: 0"; while this is distinct from strerror_r(-1,,)
  returning "Unknown error: -1", it does not imply success.  Meanwhile,
  if buf is short enough for ERANGE, then we can't use strstr to look
  for "Unknown" or "Undefined" in the resulting message, like we had
  been doing for strerror().  Fix this by shifting the burden - now
  the strerror-override code guarantees that 0 will have an
  override when needed.
  
  * lib/strerror-override.c (strerror_override): Also override 0
  when needed.
  * lib/strerror-override.h (strerror_override): Likewise.
  * lib/strerror.c (strerror): Simplify, now that 0 override is done
  earlier.
  * lib/strerror_r.c (strerror_r): Likewise.
  * m4/strerror.m4 (gl_FUNC_STRERROR): Split detection of 0
  behavior...
  (gl_FUNC_STRERROR_0): ...into new macro.
  * m4/strerror_r.m4 (gl_FUNC_STRERROR_R): Replace strerror_r if 0
  is overridden.
  (gl_FUNC_STRERROR_R_WORKS): Avoid extra tests if 0 is broken.
  * modules/strerror-override (Files): Add strerror.m4.
  (configure.ac): Also provide override for 0 when needed.
  * doc/posix-functions/strerror.texi (strerror): Document this.
  * doc/posix-functions/perror.texi (perror): Likewise.
  
  Signed-off-by: Eric Blake <eblake@redhat.com>
  

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• lib/strerror.c

• /* strerror.c --- POSIX compatible system error routine
  
     Copyright (C) 2007-2011 Free Software Foundation, Inc.
  
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU General Public License as published by
     the Free Software Foundation; either version 3 of the License, or
     (at your option) any later version.
  
     This program is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     GNU General Public License for more details.
  
     You should have received a copy of the GNU General Public License
     along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  
  #include <config.h>
  
  /* Specification.  */
  #include <string.h>
  
  #include <errno.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  
  #include "intprops.h"
  #include "strerror-override.h"
  #include "verify.h"
  
  /* Use the system functions, not the gnulib overrides in this file.  */
  #undef sprintf
  
  char *
  strerror (int n)
  #undef strerror
  {
    static char buf[STACKBUF_LEN];
    size_t len;
  
    /* Cast away const, due to the historical signature of strerror;
       callers should not be modifying the string.  */
    const char *msg = strerror_override (n);
    if (msg)
      return (char *) msg;
  
    msg = strerror (n);
  
    /* Our strerror_r implementation might use the system's strerror
       buffer, so all other clients of strerror have to see the error
       copied into a buffer that we manage.  This is not thread-safe,
       even if the system strerror is, but portable programs shouldn't
       be using strerror if they care about thread-safety.  */
    if (!msg || !*msg)
      {
        static char const fmt[] = "Unknown error %d";
        verify (sizeof buf >= sizeof (fmt) + INT_STRLEN_BOUND (n));
        sprintf (buf, fmt, n);
        errno = EINVAL;
        return buf;
      }
  
    /* Fix STACKBUF_LEN if this ever aborts.  */
    len = strlen (msg);
    if (sizeof buf <= len)
      abort ();
  
    return memcpy (buf, msg, len + 1);
  }
  

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