xref: /netbsd-src/external/gpl3/gdb/dist/gdbsupport/gdb_tilde_expand.cc (revision f8cf1a9151c7af1cb0bd8b09c13c66bca599c027)
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 }
102