[PATCH 1/2] Create new common/pathstuff.[ch]

[Sergio Durigan Junior <sergiodj at redhat dot com>]

This commit moves the path manipulation routines found on utils.c to a
new common/pathstuff.c, and updates the Makefile.in's accordingly.
The routines moved are "gdb_realpath", "gdb_realpath_keepfile" and
"gdb_abspath".

This will be needed because gdbserver will have to call "gdb_abspath"
on my next patch, which implements a way to expand the path of the
inferior provided by the user in order to allow specifying just the
binary name when starting gdbserver, like:

  $ gdbserver :1234 a.out

With the recent addition of the startup-with-shell feature on
gdbserver, this scenario doesn't work anymore if the user doesn't have
the current directory listed in the PATH variable.

I had to do a minor adjustment on "gdb_abspath" because we don't have
access to "tilde_expand" on gdbserver, so now the function is using
"gdb_tilde_expand" instead.  Otherwise, the code is the same.

Regression tested on the BuildBot, without regressions.

gdb/ChangeLog:
2018-02-09  Sergio Durigan Junior  <sergiodj@redhat.com>

	* Makefile.in (SFILES): Add "common/pathstuff.c".
	(HFILES_NO_SRCDIR): Add "common/pathstuff.h".
	(COMMON_OBS): Add "pathstuff.o".
	* common/pathstuff.c: New file.
	* common/pathstuff.h: New file.
	* utils.c (gdb_realpath): Move to "common/pathstuff.c".
	(gdb_realpath_keepfile): Likewise.
	(gdb_abspath): Likewise.
	* utils.h: Include "common/pathstuff.h".
	(gdb_realpath): Move to "common/pathstuff.h".
	(gdb_realpath_keepfile): Likewise.
	(gdb_abspath): Likewise.

gdb/gdbserver/ChangeLog:
2018-02-09  Sergio Durigan Junior  <sergiodj@redhat.com>

	* Makefile.in (SFILES): Add "$(srcdir)/common/pathstuff.c".
	(OBJS): Add "pathstuff.o".
---
 gdb/Makefile.in           |   3 +
 gdb/common/pathstuff.c    | 144 ++++++++++++++++++++++++++++++++++++++++++++++
 gdb/common/pathstuff.h    |  39 +++++++++++++
 gdb/gdbserver/Makefile.in |   2 +
 gdb/utils.c               | 119 --------------------------------------
 gdb/utils.h               |   7 +--
 6 files changed, 189 insertions(+), 125 deletions(-)
 create mode 100644 gdb/common/pathstuff.c
 create mode 100644 gdb/common/pathstuff.h

diff --git a/gdb/Makefile.in b/gdb/Makefile.in
index 957654c9bd..64c9df3eaf 100644
--- a/gdb/Makefile.in
+++ b/gdb/Makefile.in
@@ -1136,6 +1136,7 @@ SFILES = \
 	common/gdb_tilde_expand.c \
 	common/gdb_vecs.c \
 	common/new-op.c \
+	common/pathstuff.c \
 	common/print-utils.c \
 	common/ptid.c \
 	common/rsp-low.c \
@@ -1427,6 +1428,7 @@ HFILES_NO_SRCDIR = \
 	common/gdb_wait.h \
 	common/common-inferior.h \
 	common/host-defs.h \
+	common/pathstuff.h \
 	common/print-utils.h \
 	common/ptid.h \
 	common/queue.h \
@@ -1552,6 +1554,7 @@ COMMON_OBS = $(DEPFILES) $(CONFIG_OBS) $(YYOBJ) \
 	gdb_vecs.o \
 	mi/mi-common.o \
 	new-op.o \
+	pathstuff.o \
 	print-utils.o \
 	ptid.o \
 	rsp-low.o \
diff --git a/gdb/common/pathstuff.c b/gdb/common/pathstuff.c
new file mode 100644
index 0000000000..42af3fa65a
--- /dev/null
+++ b/gdb/common/pathstuff.c
@@ -0,0 +1,144 @@
+/* Path manipulation routines for GDB and gdbserver.
+
+   Copyright (C) 1986-2018 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"
+
+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] == '~')
+    {
+      std::string new_path = gdb_tilde_expand (path);
+
+      return gdb::unique_xmalloc_ptr<char> (xstrdup (new_path.c_str ()));
+    }
+
+  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));
+}
diff --git a/gdb/common/pathstuff.h b/gdb/common/pathstuff.h
new file mode 100644
index 0000000000..909fd786bb
--- /dev/null
+++ b/gdb/common/pathstuff.h
@@ -0,0 +1,39 @@
+/* Path manipulation routines for GDB and gdbserver.
+
+   Copyright (C) 1986-2018 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/>.  */
+
+#ifndef PATHSTUFF_H
+#define PATHSTUFF_H
+
+/* Path utilities.  */
+
+extern gdb::unique_xmalloc_ptr<char> gdb_realpath (const char *filename);
+
+/* Return a copy of FILENAME, with its directory prefix canonicalized
+   by gdb_realpath.  */
+
+extern gdb::unique_xmalloc_ptr<char>
+  gdb_realpath_keepfile (const char *filename);
+
+/* Return PATH in absolute form, performing tilde-expansion if necessary.
+   PATH cannot be NULL or the empty string.
+   This does not resolve symlinks however, use gdb_realpath for that.  */
+
+extern gdb::unique_xmalloc_ptr<char> gdb_abspath (const char *path);
+
+#endif /* PATHSTUFF_H */
diff --git a/gdb/gdbserver/Makefile.in b/gdb/gdbserver/Makefile.in
index 3ce086d70f..4ac068c6dd 100644
--- a/gdb/gdbserver/Makefile.in
+++ b/gdb/gdbserver/Makefile.in
@@ -209,6 +209,7 @@ SFILES = \
 	$(srcdir)/common/gdb_tilde_expand.c \
 	$(srcdir)/common/gdb_vecs.c \
 	$(srcdir)/common/new-op.c \
+	$(srcdir)/common/pathstuff.c \
 	$(srcdir)/common/print-utils.c \
 	$(srcdir)/common/ptid.c \
 	$(srcdir)/common/rsp-low.c \
@@ -256,6 +257,7 @@ OBS = \
 	mem-break.o \
 	new-op.o \
 	notif.o \
+	pathstuff.o \
 	print-utils.o \
 	ptid.o \
 	regcache.o \
diff --git a/gdb/utils.c b/gdb/utils.c
index c531748fe4..0acfad60cf 100644
--- a/gdb/utils.c
+++ b/gdb/utils.c
@@ -2838,57 +2838,6 @@ string_to_core_addr (const char *my_string)
   return addr;
 }
 
-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));
-}
-
 #if GDB_SELF_TEST
 
 static void
@@ -2925,74 +2874,6 @@ gdb_realpath_tests ()
 
 #endif /* GDB_SELF_TEST */
 
-/* Return a copy of FILENAME, with its directory prefix canonicalized
-   by gdb_realpath.  */
-
-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);
-}
-
-/* Return PATH in absolute form, performing tilde-expansion if necessary.
-   PATH cannot be NULL or the empty string.
-   This does not resolve symlinks however, use gdb_realpath for that.  */
-
-gdb::unique_xmalloc_ptr<char>
-gdb_abspath (const char *path)
-{
-  gdb_assert (path != NULL && path[0] != '\0');
-
-  if (path[0] == '~')
-    return gdb::unique_xmalloc_ptr<char> (tilde_expand (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));
-}
-
 ULONGEST
 align_up (ULONGEST v, int n)
 {
diff --git a/gdb/utils.h b/gdb/utils.h
index b234762929..4f25be0968 100644
--- a/gdb/utils.h
+++ b/gdb/utils.h
@@ -23,6 +23,7 @@
 
 #include "exceptions.h"
 #include "common/scoped_restore.h"
+#include "common/pathstuff.h"
 #include <chrono>
 
 extern void initialize_utils (void);
@@ -295,12 +296,6 @@ extern struct cleanup *make_bpstat_clear_actions_cleanup (void);
 
 /* Path utilities.  */
 
-extern gdb::unique_xmalloc_ptr<char> gdb_realpath (const char *);
-
-extern gdb::unique_xmalloc_ptr<char> gdb_realpath_keepfile (const char *);
-
-extern gdb::unique_xmalloc_ptr<char> gdb_abspath (const char *);
-
 extern int gdb_filename_fnmatch (const char *pattern, const char *string,
 				 int flags);
 
-- 
2.14.3