usr/src/cmd/sgs/libconv/common/demangle.cc

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or http://www.opensolaris.org/os/licensing.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21
  22 /*
  23  * Copyright (c) 2006, 2010, Oracle and/or its affiliates. All rights reserved.
  24  */
  25
  26 #include        <stdio.h>
  27 #include        <cxxabi.h>
  28 #include        "_conv.h"
  29 #include        "demangle_msg.h"
  30
  31 /*
  32  * Demangle C++ symbols.
  33  *
  34  * This routine acts as a generic routine for use by liblddbg (and hence tools
  35  * like elfdump(1) and pvs(1)), ld(1) and ld.so.1(1).
  36  *
  37  * The C++ ABI-2 places no limits on symbol names, thus when demangling a name
  38  * it's possible the buffer won't be big enough (return -1) so here we try to
  39  * allocate bigger buffers.  However, we place a limit on this buffer size for
  40  * fear of a C++ error sending us into an infinit loop.
  41  *
  42  * NOTE. we create and use a common buffer for use by __cxa_demangle(), thus
  43  * each call to this routine will override the contents of any existing call.
  44  * Normally this is sufficient for typical error diagnostics referencing one
  45  * symbol.  For those diagnostics using more than one symbol name, all but the
  46  * last name must be copied to a temporary buffer (regardless of whether
  47  * demangling occurred, as the process of attempting to demangle may damage the
  48  * buffer).  One model is:
  49  *
  50  *      if ((_name1 = demangle(name1)) != name1) {
  51  *              char *  __name1 = strdupa(_name1);
  52  *              name1 = (const char *)__name1;
  53  *      }
  54  *      name2 = demangle(name2);
  55  *      eprintf(format, name1, name2);
  56  */
  57 #define SYM_MAX 1000
  58
  59 const char *
  60 conv_demangle_name(const char *name)
  61 {
  62         static char     _str[SYM_MAX], *str = _str;
  63         static size_t   size = SYM_MAX;
  64         static int      again = 1;
  65         static char *   (*fptr)(const char *, char *, size_t *, int *) = 0;
  66         int             error;
  67
  68         if (str == 0)
  69                 return (name);
  70
  71         /*
  72          * If we haven't located the demangler yet try now (we do this rather
  73          * than maintain a static dependency on libstdc++). Null the str
  74          * element out to reject any other callers until this operation is
  75          * complete - under ld.so.1 we can get into serious recursion without
  76          * this.
  77          */
  78         if (fptr == 0) {
  79                 void    *hdl;
  80
  81                 str = 0;
  82                 if (!(hdl = dlopen(MSG_ORIG(MSG_DEM_LIB), RTLD_LAZY)) ||
  83                     !(fptr = (char *(*)(const char *, char *, size_t *, int *))
  84                     dlsym(hdl, MSG_ORIG(MSG_DEM_SYM))))
  85                         return (name);
  86                 str = _str;
  87         }
  88
  89         fptr(name, str, &size, &error);
  90         if (str)
  91                 return ((const char *)str);
  92
  93         while ((error == -1) && again) {
  94                 char    *_str;
  95                 size_t  _size = size;
  96
  97                 /*
  98                  * If we haven't allocated our maximum try incrementing the
  99                  * present buffer size. Use malloc() rather than realloc() so
 100                  * that we at least have the old buffer on failure.
 101                  */
 102                 if (((_size += SYM_MAX) > (SYM_MAX * 4)) ||
 103                     ((_str = (char *)malloc(_size)) == 0)) {
 104                         again = 0;
 105                         break;
 106                 }
 107                 if (size != SYM_MAX) {
 108                         free(str);
 109                 }
 110                 str = _str;
 111                 size = _size;
 112
 113                 fptr(name, str, &size, &error);
 114                 if (str)
 115                         return ((const char *)str);
 116         }
 117         return (name);
 118 }