gdb/common/pathstuff.c

   1 /* Path manipulation routines for GDB and gdbserver.
   2
   3    Copyright (C) 1986-2018 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 "common-defs.h"
  21 #include "pathstuff.h"
  22 #include "host-defs.h"
  23 #include "filenames.h"
  24 #include "gdb_tilde_expand.h"
  25
  26 /* See common/pathstuff.h.  */
  27
  28 gdb::unique_xmalloc_ptr<char>
  29 gdb_realpath (const char *filename)
  30 {
  31 /* On most hosts, we rely on canonicalize_file_name to compute
  32    the FILENAME's realpath.
  33
  34    But the situation is slightly more complex on Windows, due to some
  35    versions of GCC which were reported to generate paths where
  36    backlashes (the directory separator) were doubled.  For instance:
  37       c:\\some\\double\\slashes\\dir
  38    ... instead of ...
  39       c:\some\double\slashes\dir
  40    Those double-slashes were getting in the way when comparing paths,
  41    for instance when trying to insert a breakpoint as follow:
  42       (gdb) b c:/some/double/slashes/dir/foo.c:4
  43       No source file named c:/some/double/slashes/dir/foo.c:4.
  44       (gdb) b c:\some\double\slashes\dir\foo.c:4
  45       No source file named c:\some\double\slashes\dir\foo.c:4.
  46    To prevent this from happening, we need this function to always
  47    strip those extra backslashes.  While canonicalize_file_name does
  48    perform this simplification, it only works when the path is valid.
  49    Since the simplification would be useful even if the path is not
  50    valid (one can always set a breakpoint on a file, even if the file
  51    does not exist locally), we rely instead on GetFullPathName to
  52    perform the canonicalization.  */
  53
  54 #if defined (_WIN32)
  55   {
  56     char buf[MAX_PATH];
  57     DWORD len = GetFullPathName (filename, MAX_PATH, buf, NULL);
  58
  59     /* The file system is case-insensitive but case-preserving.
  60        So it is important we do not lowercase the path.  Otherwise,
  61        we might not be able to display the original casing in a given
  62        path.  */
  63     if (len > 0 && len < MAX_PATH)
  64       return gdb::unique_xmalloc_ptr<char> (xstrdup (buf));
  65   }
  66 #else
  67   {
  68     char *rp = canonicalize_file_name (filename);
  69
  70     if (rp != NULL)
  71       return gdb::unique_xmalloc_ptr<char> (rp);
  72   }
  73 #endif
  74
  75   /* This system is a lost cause, just dup the buffer.  */
  76   return gdb::unique_xmalloc_ptr<char> (xstrdup (filename));
  77 }
  78
  79 /* See common/pathstuff.h.  */
  80
  81 gdb::unique_xmalloc_ptr<char>
  82 gdb_realpath_keepfile (const char *filename)
  83 {
  84   const char *base_name = lbasename (filename);
  85   char *dir_name;
  86   char *result;
  87
  88   /* Extract the basename of filename, and return immediately
  89      a copy of filename if it does not contain any directory prefix.  */
  90   if (base_name == filename)
  91     return gdb::unique_xmalloc_ptr<char> (xstrdup (filename));
  92
  93   dir_name = (char *) alloca ((size_t) (base_name - filename + 2));
  94   /* Allocate enough space to store the dir_name + plus one extra
  95      character sometimes needed under Windows (see below), and
  96      then the closing \000 character.  */
  97   strncpy (dir_name, filename, base_name - filename);
  98   dir_name[base_name - filename] = '\000';
  99
 100 #ifdef HAVE_DOS_BASED_FILE_SYSTEM
 101   /* We need to be careful when filename is of the form 'd:foo', which
 102      is equivalent of d:./foo, which is totally different from d:/foo.  */
 103   if (strlen (dir_name) == 2 && isalpha (dir_name[0]) && dir_name[1] == ':')
 104     {
 105       dir_name[2] = '.';
 106       dir_name[3] = '\000';
 107     }
 108 #endif
 109
 110   /* Canonicalize the directory prefix, and build the resulting
 111      filename.  If the dirname realpath already contains an ending
 112      directory separator, avoid doubling it.  */
 113   gdb::unique_xmalloc_ptr<char> path_storage = gdb_realpath (dir_name);
 114   const char *real_path = path_storage.get ();
 115   if (IS_DIR_SEPARATOR (real_path[strlen (real_path) - 1]))
 116     result = concat (real_path, base_name, (char *) NULL);
 117   else
 118     result = concat (real_path, SLASH_STRING, base_name, (char *) NULL);
 119
 120   return gdb::unique_xmalloc_ptr<char> (result);
 121 }
 122
 123 /* See common/pathstuff.h.  */
 124
 125 gdb::unique_xmalloc_ptr<char>
 126 gdb_abspath (const char *path)
 127 {
 128   gdb_assert (path != NULL && path[0] != '\0');
 129
 130   if (path[0] == '~')
 131     return gdb_tilde_expand_up (path);
 132
 133   if (IS_ABSOLUTE_PATH (path))
 134     return gdb::unique_xmalloc_ptr<char> (xstrdup (path));
 135
 136   /* Beware the // my son, the Emacs barfs, the botch that catch...  */
 137   return gdb::unique_xmalloc_ptr<char>
 138     (concat (current_directory,
 139              IS_DIR_SEPARATOR (current_directory[strlen (current_directory) - 1])
 140              ? "" : SLASH_STRING,
 141              path, (char *) NULL));
 142 }