gdbsupport/gdb_tilde_expand.cc

   1 /* Perform tilde expansion on paths for GDB and gdbserver.
   2
   3    Copyright (C) 2017-2024 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #include <algorithm>
  21 #include "filenames.h"
  22 #include "gdb_tilde_expand.h"
  23 #include <glob.h>
  24
  25 /* RAII-style class wrapping "glob".  */
  26
  27 class gdb_glob
  28 {
  29 public:
  30   /* Construct a "gdb_glob" object by calling "glob" with the provided
  31      parameters.  This function can throw if "glob" fails.  */
  32   gdb_glob (const char *pattern, int flags,
  33             int (*errfunc) (const char *epath, int eerrno))
  34   {
  35     int ret = glob (pattern, flags, errfunc, &m_glob);
  36
  37     if (ret != 0)
  38       {
  39         if (ret == GLOB_NOMATCH)
  40           error (_("Could not find a match for '%s'."), pattern);
  41         else
  42           error (_("glob could not process pattern '%s'."),
  43                  pattern);
  44       }
  45   }
  46
  47   /* Destroy the object and free M_GLOB.  */
  48   ~gdb_glob ()
  49   {
  50     globfree (&m_glob);
  51   }
  52
  53   /* Return the GL_PATHC component of M_GLOB.  */
  54   int pathc () const
  55   {
  56     return m_glob.gl_pathc;
  57   }
  58
  59   /* Return the GL_PATHV component of M_GLOB.  */
  60   char **pathv () const
  61   {
  62     return m_glob.gl_pathv;
  63   }
  64
  65 private:
  66   /* The actual glob object we're dealing with.  */
  67   glob_t m_glob;
  68 };
  69
  70 /* See gdbsupport/gdb_tilde_expand.h.  */
  71
  72 std::string
  73 gdb_tilde_expand (const char *dir)
  74 {
  75   if (dir[0] != '~')
  76     return std::string (dir);
  77
  78   /* This function uses glob in order to expand the ~.  However, this function
  79      will fail to expand if the actual dir we are looking for does not exist.
  80      Given "~/does/not/exist", glob will fail.
  81
  82      In order to avoid such limitation, we only use glob to expand "~" and keep
  83      "/does/not/exist" unchanged.
  84
  85      Similarly, to expand ~gdb/might/not/exist, we only expand "~gdb" using
  86      glob and leave "/might/not/exist" unchanged.  */
  87   const std::string d (dir);
  88
  89   /* Look for the first dir separator (if any) and split d around it.  */
  90   const auto first_sep
  91     = std::find_if (d.cbegin (), d.cend(),
  92                     [] (const char c) -> bool
  93                       { return IS_DIR_SEPARATOR (c); });
  94   const std::string to_expand (d.cbegin (), first_sep);
  95   const std::string remainder (first_sep, d.cend ());
  96
  97   const gdb_glob glob (to_expand.c_str (), GLOB_TILDE_CHECK, nullptr);
  98
  99   gdb_assert (glob.pathc () == 1);
 100   return std::string (glob.pathv ()[0]) + remainder;
 101 }