[PATCH] Fix cache dir resolving on Windows

[orgads at gmail dot com]

From: Orgad Shaneh <orgads@gmail.com>

... when not running from MSYS environment, and HOME is not set.
---
 gdb/common/pathstuff.c | 584 +++++++++++++++++++++--------------------
 1 file changed, 294 insertions(+), 290 deletions(-)

diff --git a/gdb/common/pathstuff.c b/gdb/common/pathstuff.c
index 2b1669a5b9..33fa5bbb4d 100644
--- a/gdb/common/pathstuff.c
+++ b/gdb/common/pathstuff.c
@@ -1,290 +1,294 @@
-/* Path manipulation routines for GDB and gdbserver.
-
-   Copyright (C) 1986-2019 Free Software Foundation, Inc.
-
-   This file is part of GDB.
-
-   This program is free software; you can redistribute it and/or modify
-   it under the terms of the GNU General Public License as published by
-   the Free Software Foundation; either version 3 of the License, or
-   (at your option) any later version.
-
-   This program is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-   GNU General Public License for more details.
-
-   You should have received a copy of the GNU General Public License
-   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
-
-#include "common-defs.h"
-#include "pathstuff.h"
-#include "host-defs.h"
-#include "filenames.h"
-#include "gdb_tilde_expand.h"
-
-#ifdef USE_WIN32API
-#include <windows.h>
-#endif
-
-/* See common/pathstuff.h.  */
-
-gdb::unique_xmalloc_ptr<char>
-gdb_realpath (const char *filename)
-{
-/* On most hosts, we rely on canonicalize_file_name to compute
-   the FILENAME's realpath.
-
-   But the situation is slightly more complex on Windows, due to some
-   versions of GCC which were reported to generate paths where
-   backlashes (the directory separator) were doubled.  For instance:
-      c:\\some\\double\\slashes\\dir
-   ... instead of ...
-      c:\some\double\slashes\dir
-   Those double-slashes were getting in the way when comparing paths,
-   for instance when trying to insert a breakpoint as follow:
-      (gdb) b c:/some/double/slashes/dir/foo.c:4
-      No source file named c:/some/double/slashes/dir/foo.c:4.
-      (gdb) b c:\some\double\slashes\dir\foo.c:4
-      No source file named c:\some\double\slashes\dir\foo.c:4.
-   To prevent this from happening, we need this function to always
-   strip those extra backslashes.  While canonicalize_file_name does
-   perform this simplification, it only works when the path is valid.
-   Since the simplification would be useful even if the path is not
-   valid (one can always set a breakpoint on a file, even if the file
-   does not exist locally), we rely instead on GetFullPathName to
-   perform the canonicalization.  */
-
-#if defined (_WIN32)
-  {
-    char buf[MAX_PATH];
-    DWORD len = GetFullPathName (filename, MAX_PATH, buf, NULL);
-
-    /* The file system is case-insensitive but case-preserving.
-       So it is important we do not lowercase the path.  Otherwise,
-       we might not be able to display the original casing in a given
-       path.  */
-    if (len > 0 && len < MAX_PATH)
-      return gdb::unique_xmalloc_ptr<char> (xstrdup (buf));
-  }
-#else
-  {
-    char *rp = canonicalize_file_name (filename);
-
-    if (rp != NULL)
-      return gdb::unique_xmalloc_ptr<char> (rp);
-  }
-#endif
-
-  /* This system is a lost cause, just dup the buffer.  */
-  return gdb::unique_xmalloc_ptr<char> (xstrdup (filename));
-}
-
-/* See common/pathstuff.h.  */
-
-gdb::unique_xmalloc_ptr<char>
-gdb_realpath_keepfile (const char *filename)
-{
-  const char *base_name = lbasename (filename);
-  char *dir_name;
-  char *result;
-
-  /* Extract the basename of filename, and return immediately
-     a copy of filename if it does not contain any directory prefix.  */
-  if (base_name == filename)
-    return gdb::unique_xmalloc_ptr<char> (xstrdup (filename));
-
-  dir_name = (char *) alloca ((size_t) (base_name - filename + 2));
-  /* Allocate enough space to store the dir_name + plus one extra
-     character sometimes needed under Windows (see below), and
-     then the closing \000 character.  */
-  strncpy (dir_name, filename, base_name - filename);
-  dir_name[base_name - filename] = '\000';
-
-#ifdef HAVE_DOS_BASED_FILE_SYSTEM
-  /* We need to be careful when filename is of the form 'd:foo', which
-     is equivalent of d:./foo, which is totally different from d:/foo.  */
-  if (strlen (dir_name) == 2 && isalpha (dir_name[0]) && dir_name[1] == ':')
-    {
-      dir_name[2] = '.';
-      dir_name[3] = '\000';
-    }
-#endif
-
-  /* Canonicalize the directory prefix, and build the resulting
-     filename.  If the dirname realpath already contains an ending
-     directory separator, avoid doubling it.  */
-  gdb::unique_xmalloc_ptr<char> path_storage = gdb_realpath (dir_name);
-  const char *real_path = path_storage.get ();
-  if (IS_DIR_SEPARATOR (real_path[strlen (real_path) - 1]))
-    result = concat (real_path, base_name, (char *) NULL);
-  else
-    result = concat (real_path, SLASH_STRING, base_name, (char *) NULL);
-
-  return gdb::unique_xmalloc_ptr<char> (result);
-}
-
-/* See common/pathstuff.h.  */
-
-gdb::unique_xmalloc_ptr<char>
-gdb_abspath (const char *path)
-{
-  gdb_assert (path != NULL && path[0] != '\0');
-
-  if (path[0] == '~')
-    return gdb_tilde_expand_up (path);
-
-  if (IS_ABSOLUTE_PATH (path))
-    return gdb::unique_xmalloc_ptr<char> (xstrdup (path));
-
-  /* Beware the // my son, the Emacs barfs, the botch that catch...  */
-  return gdb::unique_xmalloc_ptr<char>
-    (concat (current_directory,
-	     IS_DIR_SEPARATOR (current_directory[strlen (current_directory) - 1])
-	     ? "" : SLASH_STRING,
-	     path, (char *) NULL));
-}
-
-/* See common/pathstuff.h.  */
-
-const char *
-child_path (const char *parent, const char *child)
-{
-  /* The child path must start with the parent path.  */
-  size_t parent_len = strlen (parent);
-  if (filename_ncmp (parent, child, parent_len) != 0)
-    return NULL;
-
-  /* The parent path must be a directory and the child must contain at
-     least one component underneath the parent.  */
-  const char *child_component;
-  if (IS_DIR_SEPARATOR (parent[parent_len - 1]))
-    {
-      /* The parent path ends in a directory separator, so it is a
-	 directory.  The first child component starts after the common
-	 prefix.  */
-      child_component = child + parent_len;
-    }
-  else
-    {
-      /* The parent path does not end in a directory separator.  The
-	 first character in the child after the common prefix must be
-	 a directory separator.
-
-	 Note that CHILD must hold at least parent_len characters for
-	 filename_ncmp to return zero.  If the character at parent_len
-	 is nul due to CHILD containing the same path as PARENT, the
-	 IS_DIR_SEPARATOR check will fail here.  */
-      if (!IS_DIR_SEPARATOR (child[parent_len]))
-	return NULL;
-
-      /* The first child component starts after the separator after the
-	 common prefix.  */
-      child_component = child + parent_len + 1;
-    }
-
-  /* The child must contain at least one non-separator character after
-     the parent.  */
-  while (*child_component != '\0')
-    {
-      if (!IS_DIR_SEPARATOR (*child_component))
-	return child_component;
-
-      child_component++;
-    }
-  return NULL;
-}
-
-/* See common/pathstuff.h.  */
-
-bool
-contains_dir_separator (const char *path)
-{
-  for (; *path != '\0'; path++)
-    {
-      if (IS_DIR_SEPARATOR (*path))
-	return true;
-    }
-
-  return false;
-}
-
-/* See common/pathstuff.h.  */
-
-std::string
-get_standard_cache_dir ()
-{
-#ifdef __APPLE__
-#define HOME_CACHE_DIR "Library/Caches"
-#else
-#define HOME_CACHE_DIR ".cache"
-#endif
-
-#ifndef __APPLE__
-  const char *xdg_cache_home = getenv ("XDG_CACHE_HOME");
-  if (xdg_cache_home != NULL)
-    {
-      /* Make sure the path is absolute and tilde-expanded.  */
-      gdb::unique_xmalloc_ptr<char> abs (gdb_abspath (xdg_cache_home));
-      return string_printf ("%s/gdb", abs.get ());
-    }
-#endif
-
-  const char *home = getenv ("HOME");
-  if (home != NULL)
-    {
-      /* Make sure the path is absolute and tilde-expanded.  */
-      gdb::unique_xmalloc_ptr<char> abs (gdb_abspath (home));
-      return string_printf ("%s/" HOME_CACHE_DIR "/gdb", abs.get ());
-    }
-
-  return {};
-}
-
-/* See common/pathstuff.h.  */
-
-std::string
-get_standard_temp_dir ()
-{
-#ifdef WIN32
-  const char *tmp = getenv ("TMP");
-  if (tmp != nullptr)
-    return tmp;
-
-  tmp = getenv ("TEMP");
-  if (tmp != nullptr)
-    return tmp;
-
-  error (_("Couldn't find temp dir path, both TMP and TEMP are unset."));
-
-#else
-  const char *tmp = getenv ("TMPDIR");
-  if (tmp != nullptr)
-    return tmp;
-
-  return "/tmp";
-#endif
-}
-
-/* See common/pathstuff.h.  */
-
-const char *
-get_shell ()
-{
-  const char *ret = getenv ("SHELL");
-  if (ret == NULL)
-    ret = "/bin/sh";
-
-  return ret;
-}
-
-/* See common/pathstuff.h.  */
-
-gdb::char_vector
-make_temp_filename (const std::string &f)
-{
-  gdb::char_vector filename_temp (f.length () + 8);
-  strcpy (filename_temp.data (), f.c_str ());
-  strcat (filename_temp.data () + f.size (), "-XXXXXX");
-  return filename_temp;
-}
+/* Path manipulation routines for GDB and gdbserver.
+
+   Copyright (C) 1986-2019 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include "common-defs.h"
+#include "pathstuff.h"
+#include "host-defs.h"
+#include "filenames.h"
+#include "gdb_tilde_expand.h"
+
+#ifdef USE_WIN32API
+#include <windows.h>
+#endif
+
+/* See common/pathstuff.h.  */
+
+gdb::unique_xmalloc_ptr<char>
+gdb_realpath (const char *filename)
+{
+/* On most hosts, we rely on canonicalize_file_name to compute
+   the FILENAME's realpath.
+
+   But the situation is slightly more complex on Windows, due to some
+   versions of GCC which were reported to generate paths where
+   backlashes (the directory separator) were doubled.  For instance:
+      c:\\some\\double\\slashes\\dir
+   ... instead of ...
+      c:\some\double\slashes\dir
+   Those double-slashes were getting in the way when comparing paths,
+   for instance when trying to insert a breakpoint as follow:
+      (gdb) b c:/some/double/slashes/dir/foo.c:4
+      No source file named c:/some/double/slashes/dir/foo.c:4.
+      (gdb) b c:\some\double\slashes\dir\foo.c:4
+      No source file named c:\some\double\slashes\dir\foo.c:4.
+   To prevent this from happening, we need this function to always
+   strip those extra backslashes.  While canonicalize_file_name does
+   perform this simplification, it only works when the path is valid.
+   Since the simplification would be useful even if the path is not
+   valid (one can always set a breakpoint on a file, even if the file
+   does not exist locally), we rely instead on GetFullPathName to
+   perform the canonicalization.  */
+
+#if defined (_WIN32)
+  {
+    char buf[MAX_PATH];
+    DWORD len = GetFullPathName (filename, MAX_PATH, buf, NULL);
+
+    /* The file system is case-insensitive but case-preserving.
+       So it is important we do not lowercase the path.  Otherwise,
+       we might not be able to display the original casing in a given
+       path.  */
+    if (len > 0 && len < MAX_PATH)
+      return gdb::unique_xmalloc_ptr<char> (xstrdup (buf));
+  }
+#else
+  {
+    char *rp = canonicalize_file_name (filename);
+
+    if (rp != NULL)
+      return gdb::unique_xmalloc_ptr<char> (rp);
+  }
+#endif
+
+  /* This system is a lost cause, just dup the buffer.  */
+  return gdb::unique_xmalloc_ptr<char> (xstrdup (filename));
+}
+
+/* See common/pathstuff.h.  */
+
+gdb::unique_xmalloc_ptr<char>
+gdb_realpath_keepfile (const char *filename)
+{
+  const char *base_name = lbasename (filename);
+  char *dir_name;
+  char *result;
+
+  /* Extract the basename of filename, and return immediately
+     a copy of filename if it does not contain any directory prefix.  */
+  if (base_name == filename)
+    return gdb::unique_xmalloc_ptr<char> (xstrdup (filename));
+
+  dir_name = (char *) alloca ((size_t) (base_name - filename + 2));
+  /* Allocate enough space to store the dir_name + plus one extra
+     character sometimes needed under Windows (see below), and
+     then the closing \000 character.  */
+  strncpy (dir_name, filename, base_name - filename);
+  dir_name[base_name - filename] = '\000';
+
+#ifdef HAVE_DOS_BASED_FILE_SYSTEM
+  /* We need to be careful when filename is of the form 'd:foo', which
+     is equivalent of d:./foo, which is totally different from d:/foo.  */
+  if (strlen (dir_name) == 2 && isalpha (dir_name[0]) && dir_name[1] == ':')
+    {
+      dir_name[2] = '.';
+      dir_name[3] = '\000';
+    }
+#endif
+
+  /* Canonicalize the directory prefix, and build the resulting
+     filename.  If the dirname realpath already contains an ending
+     directory separator, avoid doubling it.  */
+  gdb::unique_xmalloc_ptr<char> path_storage = gdb_realpath (dir_name);
+  const char *real_path = path_storage.get ();
+  if (IS_DIR_SEPARATOR (real_path[strlen (real_path) - 1]))
+    result = concat (real_path, base_name, (char *) NULL);
+  else
+    result = concat (real_path, SLASH_STRING, base_name, (char *) NULL);
+
+  return gdb::unique_xmalloc_ptr<char> (result);
+}
+
+/* See common/pathstuff.h.  */
+
+gdb::unique_xmalloc_ptr<char>
+gdb_abspath (const char *path)
+{
+  gdb_assert (path != NULL && path[0] != '\0');
+
+  if (path[0] == '~')
+    return gdb_tilde_expand_up (path);
+
+  if (IS_ABSOLUTE_PATH (path))
+    return gdb::unique_xmalloc_ptr<char> (xstrdup (path));
+
+  /* Beware the // my son, the Emacs barfs, the botch that catch...  */
+  return gdb::unique_xmalloc_ptr<char>
+    (concat (current_directory,
+	     IS_DIR_SEPARATOR (current_directory[strlen (current_directory) - 1])
+	     ? "" : SLASH_STRING,
+	     path, (char *) NULL));
+}
+
+/* See common/pathstuff.h.  */
+
+const char *
+child_path (const char *parent, const char *child)
+{
+  /* The child path must start with the parent path.  */
+  size_t parent_len = strlen (parent);
+  if (filename_ncmp (parent, child, parent_len) != 0)
+    return NULL;
+
+  /* The parent path must be a directory and the child must contain at
+     least one component underneath the parent.  */
+  const char *child_component;
+  if (IS_DIR_SEPARATOR (parent[parent_len - 1]))
+    {
+      /* The parent path ends in a directory separator, so it is a
+	 directory.  The first child component starts after the common
+	 prefix.  */
+      child_component = child + parent_len;
+    }
+  else
+    {
+      /* The parent path does not end in a directory separator.  The
+	 first character in the child after the common prefix must be
+	 a directory separator.
+
+	 Note that CHILD must hold at least parent_len characters for
+	 filename_ncmp to return zero.  If the character at parent_len
+	 is nul due to CHILD containing the same path as PARENT, the
+	 IS_DIR_SEPARATOR check will fail here.  */
+      if (!IS_DIR_SEPARATOR (child[parent_len]))
+	return NULL;
+
+      /* The first child component starts after the separator after the
+	 common prefix.  */
+      child_component = child + parent_len + 1;
+    }
+
+  /* The child must contain at least one non-separator character after
+     the parent.  */
+  while (*child_component != '\0')
+    {
+      if (!IS_DIR_SEPARATOR (*child_component))
+	return child_component;
+
+      child_component++;
+    }
+  return NULL;
+}
+
+/* See common/pathstuff.h.  */
+
+bool
+contains_dir_separator (const char *path)
+{
+  for (; *path != '\0'; path++)
+    {
+      if (IS_DIR_SEPARATOR (*path))
+	return true;
+    }
+
+  return false;
+}
+
+/* See common/pathstuff.h.  */
+
+std::string
+get_standard_cache_dir ()
+{
+#ifdef __APPLE__
+#define HOME_CACHE_DIR "Library/Caches"
+#else
+#define HOME_CACHE_DIR ".cache"
+#endif
+
+#ifndef __APPLE__
+  const char *xdg_cache_home = getenv ("XDG_CACHE_HOME");
+  if (xdg_cache_home != NULL)
+    {
+      /* Make sure the path is absolute and tilde-expanded.  */
+      gdb::unique_xmalloc_ptr<char> abs (gdb_abspath (xdg_cache_home));
+      return string_printf ("%s/gdb", abs.get ());
+    }
+#endif
+
+  const char *home = getenv ("HOME");
+#ifdef _WIN32
+  if (home == nullptr)
+      home = getenv ("APPDATA");
+#endif
+  if (home != NULL)
+    {
+      /* Make sure the path is absolute and tilde-expanded.  */
+      gdb::unique_xmalloc_ptr<char> abs (gdb_abspath (home));
+      return string_printf ("%s/" HOME_CACHE_DIR "/gdb", abs.get ());
+    }
+
+  return {};
+}
+
+/* See common/pathstuff.h.  */
+
+std::string
+get_standard_temp_dir ()
+{
+#ifdef WIN32
+  const char *tmp = getenv ("TMP");
+  if (tmp != nullptr)
+    return tmp;
+
+  tmp = getenv ("TEMP");
+  if (tmp != nullptr)
+    return tmp;
+
+  error (_("Couldn't find temp dir path, both TMP and TEMP are unset."));
+
+#else
+  const char *tmp = getenv ("TMPDIR");
+  if (tmp != nullptr)
+    return tmp;
+
+  return "/tmp";
+#endif
+}
+
+/* See common/pathstuff.h.  */
+
+const char *
+get_shell ()
+{
+  const char *ret = getenv ("SHELL");
+  if (ret == NULL)
+    ret = "/bin/sh";
+
+  return ret;
+}
+
+/* See common/pathstuff.h.  */
+
+gdb::char_vector
+make_temp_filename (const std::string &f)
+{
+  gdb::char_vector filename_temp (f.length () + 8);
+  strcpy (filename_temp.data (), f.c_str ());
+  strcat (filename_temp.data () + f.size (), "-XXXXXX");
+  return filename_temp;
+}
-- 
2.20.1