6375 Add native name demangling support
Reviewed by: Robert Mustacchi <rm@joyent.com>
Reviewed by: Richard Lowe <richlowe@richlowe.net>

*** 22,31 ****
--- 22,32 ----
  /*
   *      Copyright (c) 1988 AT&T
   *        All Rights Reserved
   *
   * Copyright (c) 1989, 2010, Oracle and/or its affiliates. All rights reserved.
+  * Copyright 2018, Joyent, Inc.
   */
  
  /* Get definitions for the relocation types supported. */
  #define ELF_TARGET_ALL
  
*** 475,506 ****
  /* demangle C++ names */
  static char *
  demangled_name(char *s)
  {
          static char     *buf = NULL;
!         const char      *dn;
          size_t          len;
  
!         dn = conv_demangle_name(s);
  
          /*
           * If not demangled, just return the symbol name
           */
!         if (strcmp(s, dn) == 0)
                  return (s);
  
-         /*
-          * Demangled. Format it
-          */
-         if (buf != NULL)
-                 free(buf);
- 
          len = strlen(dn) + strlen(s) + 4;
          if ((buf = malloc(len)) == NULL)
                  return (s);
  
!         (void) snprintf(buf, len, "%s\t[%s]", dn, s);
          return (buf);
  }
  
  /*
   * Print the symbol table.  Input is an ELF file descriptor, a
--- 476,511 ----
  /* demangle C++ names */
  static char *
  demangled_name(char *s)
  {
          static char     *buf = NULL;
!         size_t          buflen = 0;
!         char            *dn;
          size_t          len;
  
!         dn = (char *)conv_demangle_name(s);
  
          /*
           * If not demangled, just return the symbol name
           */
!         if (dn == s)
                  return (s);
  
          len = strlen(dn) + strlen(s) + 4;
+ 
+         if (buflen < len) {
+                 free(buf);
                  if ((buf = malloc(len)) == NULL)
                          return (s);
+                 buflen = len;
+         }
  
!         /*
!          * Demangled. Format it
!          */
!         (void) snprintf(buf, buflen, "%s\t[%s]", dn, s);
!         free(dn);
          return (buf);
  }
  
  /*
   * Print the symbol table.  Input is an ELF file descriptor, a
*** 524,534 ****
  
          if (gelf_getclass(elf_file) == ELFCLASS64)
                  adj = 8;
  
          while (range > 0) {
!                 char            *sym_name = (char *)0;
                  int             type, bind;
                  int             specsec;
                  unsigned int    shndx;
  
                  (void) gelf_getsym(sym_data, index, &sym);
--- 529,539 ----
  
          if (gelf_getclass(elf_file) == ELFCLASS64)
                  adj = 8;
  
          while (range > 0) {
!                 char            *sym_name = NULL;
                  int             type, bind;
                  int             specsec;
                  unsigned int    shndx;
  
                  (void) gelf_getsym(sym_data, index, &sym);