[patchv2] Improve Executable displayed path (PR 15415 regression kind #2)

[Jan Kratochvil <jan dot kratochvil at redhat dot com>]

On Wed, 04 Sep 2013 12:48:41 +0200, Pedro Alves wrote:
> It seems this patch introduces some output inconsistency
> (only tried mainline):
> 
>  $ ./gdb
>  ...
>  (gdb) file ./gdb
>  Reading symbols from /home/pedro/gdb/mygit/build/gdb/gdb...done.
>  Setting up the environment for debugging gdb.
>  (top-gdb) info inferiors
>    Num  Description       Executable
>  * 1    <null>            /home/pedro/gdb/mygit/build/gdb/./gdb
>  (top-gdb)
> 
> Note "gdb/gdb" vs "gdb/./gdb".
> 
>  (top-gdb) file gdbserver/../gdb
>  Load new symbol table from "/home/pedro/gdb/mygit/build/gdb/gdb"? (y or n) y
>  Reading symbols from /home/pedro/gdb/mygit/build/gdb/gdb...done.
>  (top-gdb) info inferiors
>    Num  Description       Executable
>  * 1    <null>            /home/pedro/gdb/mygit/build/gdb/gdbserver/../gdb
>  (top-gdb)
> 
> Note ".../gdb/gdb" vs ".../gdb/gdbserver/../gdb".

This patch reintroduces xfullpath although IMO under a better name
gdb_realpath_keepfile, to make the name similar to gdb_realpath.
xfullpath was removed by:
	commit bfacf227ec8ee6b1c73311e323bd93c1eddd9ca6
	Author: Jan Kratochvil <jan.kratochvil@redhat.com>
	Date:   Sun Feb 3 15:54:14 2013 +0000
		Replace xfullpath calls by gdb_realpath calls.

$ ln -s . symlinkdir
$ ln -s file symlinkfile

Output is verified for:
	gdb --args ./symlinkdir/symlinkfile
	gdb ./symlinkdir/symlinkfile
	info inferiors
	inferior argv[0]

<=gdb-7.5      /absdir/symlinkfile
gdb-7.6        /absdir/file
gdb-7.6.1+HEAD /absdir/./symlinkdir/symlinkfile
this patch     /absdir/symlinkfile

Therefore this patch now fully restores the pre-7.6 behavior:

<=gdb-7.5 or this patch
PASS: gdb.base/argv0-symlink.exp: kept file symbolic link name
PASS: gdb.base/argv0-symlink.exp: kept file symbolic link name for info inferiors
KFAIL: gdb.base/argv0-symlink.exp: kept directory symbolic link name (PRMS: gdb/15934)
PASS: gdb.base/argv0-symlink.exp: kept directory symbolic link name for info inferiors

gdb-7.6.1 or HEAD
PASS: gdb.base/argv0-symlink.exp: kept file symbolic link name
PASS: gdb.base/argv0-symlink.exp: kept file symbolic link name for info inferiors
KPASS: gdb.base/argv0-symlink.exp: kept directory symbolic link name (PRMS gdb/15934)
FAIL: gdb.base/argv0-symlink.exp: kept directory symbolic link name for info inferiors

gdb-7.6
FAIL: gdb.base/argv0-symlink.exp: kept file symbolic link name
FAIL: gdb.base/argv0-symlink.exp: kept file symbolic link name for info inferiors
KFAIL: gdb.base/argv0-symlink.exp: kept directory symbolic link name (PRMS: gdb/15934)
FAIL: gdb.base/argv0-symlink.exp: kept directory symbolic link name for info inferiors


I had to file new KFAIL
	Keep directories for argv[0]
	https://sourceware.org/bugzilla/show_bug.cgi?id=15934
as this patch no longer keeps argv[0] (its directories) intact, exactly like
<=gdb-7.5 behaved.  I do not think it matters, though, more details in this
filed PR.


Jan


gdb/
2013-09-05  Jan Kratochvil  <jan.kratochvil@redhat.com>

	Canonicalize directories for EXEC_FILENAME.
	* exec.c (exec_file_attach): Use gdb_realpath_keepfile for
	exec_filename.
	* utils.c (gdb_realpath_keepfile): New function.
	* utils.h (gdb_realpath_keepfile): New declaration.

gdb/testsuite/
2013-09-24  Jan Kratochvil  <jan.kratochvil@redhat.com>

	* gdb.base/argv0-symlink.exp
	(kept file symbolic link name for info inferiors): New.
	(kept directory symbolic link name): Setup kfail.
	(kept directory symbolic link name for info inferiors): New.

diff --git a/gdb/exec.c b/gdb/exec.c
index c7370e3..758cdc1 100644
--- a/gdb/exec.c
+++ b/gdb/exec.c
@@ -224,7 +224,7 @@ exec_file_attach (char *filename, int from_tty)
 	}
 
       gdb_assert (exec_filename == NULL);
-      exec_filename = xstrdup (scratch_pathname);
+      exec_filename = gdb_realpath_keepfile (scratch_pathname);
 
       if (!bfd_check_format_matches (exec_bfd, bfd_object, &matching))
 	{
diff --git a/gdb/testsuite/gdb.base/argv0-symlink.exp b/gdb/testsuite/gdb.base/argv0-symlink.exp
index dc11f74..cf5785c 100644
--- a/gdb/testsuite/gdb.base/argv0-symlink.exp
+++ b/gdb/testsuite/gdb.base/argv0-symlink.exp
@@ -37,6 +37,7 @@ if ![runto_main] {
 }
 
 gdb_test {print argv[0]} "/$filelink\"" $test
+gdb_test "info inferiors" "/$subdir/$filelink *" "$test for info inferiors"
 
 
 set test "kept directory symbolic link name"
@@ -59,4 +60,9 @@ if ![runto_main] {
     return -1
 }
 
+# gdbserver does not have this issue.
+if ![is_remote target] {
+    setup_kfail "*-*-*" gdb/15934
+}
 gdb_test {print argv[0]} "/$dirlink/$filelink\"" $test
+gdb_test "info inferiors" "/$subdir/$filelink *" "$test for info inferiors"
diff --git a/gdb/utils.c b/gdb/utils.c
index 0652197..b6914ff 100644
--- a/gdb/utils.c
+++ b/gdb/utils.c
@@ -3204,6 +3204,52 @@ gdb_realpath (const char *filename)
   return xstrdup (filename);
 }
 
+/* Return a copy of FILENAME, with its directory prefix canonicalized
+   by gdb_realpath.  */
+
+char *
+gdb_realpath_keepfile (const char *filename)
+{
+  const char *base_name = lbasename (filename);
+  char *dir_name;
+  char *real_path;
+  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 xstrdup (filename);
+
+  dir_name = 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.  */
+  real_path = gdb_realpath (dir_name);
+  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);
+
+  xfree (real_path);
+  return result;
+}
+
 ULONGEST
 align_up (ULONGEST v, int n)
 {
diff --git a/gdb/utils.h b/gdb/utils.h
index 143cd6b..e917dae 100644
--- a/gdb/utils.h
+++ b/gdb/utils.h
@@ -128,6 +128,8 @@ extern struct cleanup *make_bpstat_clear_actions_cleanup (void);
 
 extern char *gdb_realpath (const char *);
 
+extern char *gdb_realpath_keepfile (const char *);
+
 extern int gdb_filename_fnmatch (const char *pattern, const char *string,
 				 int flags);