[v2,3/5] Introduce gdb_chdir
Commit Message
In order to be able to change the inferior's directory before its
execution, it is necessary to perform a tilde expansion of the
directory provided by the user and then chdir into the resulting dir.
This is what gdb_chdir does.
Unfortunately it is not possible to use "tilde_expand" from readline
because this is common code and gdbserver doesn't use readline. For
that reason I decided to go with "glob" and its GNU extension,
GLOB_TILDE. With the import of the "glob" module from gnulib, this is
a no-brainer.
gdb/ChangeLog:
yyyy-mm-dd Sergio Durigan Junior <sergiodj@redhat.com>
* Makefile.in (SFILES): Add gdb_chdir.c.
(HFILES_NO_SRCDIR): Add gdb_chdir.h.
(COMMON_OBS): Add gdb_chdir.o.
* cli/cli-cmds.c: Include "gdb_chdir.h".
(cd_command): Use "gdb_chdir" instead of "tilde_expand
plus chdir".
* common/gdb_chdir.c: New file.
* common/gdb_chdir.h: Likewise.
gdb/gdbserver/ChangeLog:
yyyy-mm-dd Sergio Durigan Junior <sergiodj@redhat.com>
* Makefile.in (SFILES): Add $(srcdir)/common/gdb_chdir.c.
(OBS): Add gdb_chdir.o.
---
gdb/Makefile.in | 3 ++
gdb/cli/cli-cmds.c | 20 +++++-----
gdb/common/gdb_chdir.c | 96 +++++++++++++++++++++++++++++++++++++++++++++++
gdb/common/gdb_chdir.h | 26 +++++++++++++
gdb/gdbserver/Makefile.in | 2 +
5 files changed, 136 insertions(+), 11 deletions(-)
create mode 100644 gdb/common/gdb_chdir.c
create mode 100644 gdb/common/gdb_chdir.h
Comments
On 09/19/2017 05:28 AM, Sergio Durigan Junior wrote:
> In order to be able to change the inferior's directory before its
> execution, it is necessary to perform a tilde expansion of the
> directory provided by the user and then chdir into the resulting dir.
> This is what gdb_chdir does.
>
> Unfortunately it is not possible to use "tilde_expand" from readline
> because this is common code and gdbserver doesn't use readline. For
> that reason I decided to go with "glob" and its GNU extension,
> GLOB_TILDE. With the import of the "glob" module from gnulib, this is
> a no-brainer.
>
> gdb/ChangeLog:
> yyyy-mm-dd Sergio Durigan Junior <sergiodj@redhat.com>
>
> * Makefile.in (SFILES): Add gdb_chdir.c.
> (HFILES_NO_SRCDIR): Add gdb_chdir.h.
> (COMMON_OBS): Add gdb_chdir.o.
> * cli/cli-cmds.c: Include "gdb_chdir.h".
> (cd_command): Use "gdb_chdir" instead of "tilde_expand
> plus chdir".
> * common/gdb_chdir.c: New file.
> * common/gdb_chdir.h: Likewise.
>
> gdb/gdbserver/ChangeLog:
> yyyy-mm-dd Sergio Durigan Junior <sergiodj@redhat.com>
>
> * Makefile.in (SFILES): Add $(srcdir)/common/gdb_chdir.c.
> (OBS): Add gdb_chdir.o.
> ---
> gdb/Makefile.in | 3 ++
> gdb/cli/cli-cmds.c | 20 +++++-----
> gdb/common/gdb_chdir.c | 96 +++++++++++++++++++++++++++++++++++++++++++++++
> gdb/common/gdb_chdir.h | 26 +++++++++++++
> gdb/gdbserver/Makefile.in | 2 +
> 5 files changed, 136 insertions(+), 11 deletions(-)
> create mode 100644 gdb/common/gdb_chdir.c
> create mode 100644 gdb/common/gdb_chdir.h
>
> diff --git a/gdb/Makefile.in b/gdb/Makefile.in
> index 9dfc117b2f..1f093e6c0f 100644
> --- a/gdb/Makefile.in
> +++ b/gdb/Makefile.in
> @@ -1245,6 +1245,7 @@ SFILES = \
> common/filestuff.c \
> common/format.c \
> common/job-control.c \
> + common/gdb_chdir.c \
> common/gdb_vecs.c \
> common/new-op.c \
> common/print-utils.c \
> @@ -1529,6 +1530,7 @@ HFILES_NO_SRCDIR = \
> common/fileio.h \
> common/format.h \
> common/gdb_assert.h \
> + common/gdb_chdir.h \
> common/gdb_locale.h \
> common/gdb_setjmp.h \
> common/gdb_signals.h \
> @@ -1734,6 +1736,7 @@ COMMON_OBS = $(DEPFILES) $(CONFIG_OBS) $(YYOBJ) \
> frame-unwind.o \
> gcore.o \
> gdb_bfd.o \
> + gdb_chdir.o \
> gdb-dlfcn.o \
> gdb_obstack.o \
> gdb_regex.o \
> diff --git a/gdb/cli/cli-cmds.c b/gdb/cli/cli-cmds.c
> index 85d6d21113..653dd56a64 100644
> --- a/gdb/cli/cli-cmds.c
> +++ b/gdb/cli/cli-cmds.c
> @@ -54,6 +54,8 @@
> #include "tui/tui.h" /* For tui_active et.al. */
> #endif
>
> +#include "gdb_chdir.h"
> +
> #include <fcntl.h>
> #include <algorithm>
> #include <string>
> @@ -408,12 +410,7 @@ cd_command (char *dir, int from_tty)
> repeat might be useful but is more likely to be a mistake. */
> dont_repeat ();
>
> - gdb::unique_xmalloc_ptr<char> dir_holder
> - (tilde_expand (dir != NULL ? dir : "~"));
> - dir = dir_holder.get ();
> -
> - if (chdir (dir) < 0)
> - perror_with_name (dir);
> + gdb_chdir (dir != NULL ? dir : "~");
>
> #ifdef HAVE_DOS_BASED_FILE_SYSTEM
> /* There's too much mess with DOSish names like "d:", "d:.",
> @@ -436,20 +433,21 @@ cd_command (char *dir, int from_tty)
> len--;
> }
>
> - dir_holder.reset (savestring (dir, len));
> - if (IS_ABSOLUTE_PATH (dir_holder.get ()))
> + std::string newdir = std::string (dir, len);
> + const char *newdir_str = newdir.c_str ();
> + if (IS_ABSOLUTE_PATH (newdir_str))
> {
> xfree (current_directory);
> - current_directory = dir_holder.release ();
> + current_directory = xstrdup (newdir_str);
This introduces one extra deep string dup. One to
construct the std::string, and another here in this xstrdup.
How about simply, above:
- dir_holder.reset (savestring (dir, len));
+ gdb::unique_xmalloc_ptr<char> dir_holder (savestring (dir, len))
But more importantly, isn't there a behavior change here?
Before, current_directory would be a copy of the the expand
path, while after the patch, it's a copy of the input string,
before expansion. Right?
> }
> else
> {
> if (IS_DIR_SEPARATOR (current_directory[strlen (current_directory) - 1]))
> - current_directory = concat (current_directory, dir_holder.get (),
> + current_directory = concat (current_directory, newdir_str,
> (char *) NULL);
> else
> current_directory = concat (current_directory, SLASH_STRING,
> - dir_holder.get (), (char *) NULL);
> + newdir_str, (char *) NULL);
> }
> + /* Destroy the object and free M_GLOB. */
> + ~gdb_glob ()
> + {
> + globfree (&m_glob);
> + }
> +
> + /* Return the GL_PATHC component of M_GLOB. */
> + int
> + pathc () const
> + {
> + return m_glob.gl_pathc;
> + }
We've been putting type and function name in the
same line in inline member functions. That's the
de facto standard in GCC as well, AFAICS.
> +
> + /* Return the GL_PATHV component of M_GLOB. */
> + char **
> + pathv () const
> + {
> + return m_glob.gl_pathv;
> + }
Ditto.
> +#ifndef HAVE_GDB_CHDIR_H
> +#define HAVE_GDB_CHDIR_H
> +
> +/* Perform a "chdir" to DIR, doing the proper tilde expansion before. */
> +extern void gdb_chdir (const char *dir);
Nit, I'd drop "the proper", as it doesn't see to add value.
I.e., what's proper and what's not proper?
Thanks,
Pedro Alves
On Wednesday, September 20 2017, Pedro Alves wrote:
> On 09/19/2017 05:28 AM, Sergio Durigan Junior wrote:
>> In order to be able to change the inferior's directory before its
>> execution, it is necessary to perform a tilde expansion of the
>> directory provided by the user and then chdir into the resulting dir.
>> This is what gdb_chdir does.
>>
>> Unfortunately it is not possible to use "tilde_expand" from readline
>> because this is common code and gdbserver doesn't use readline. For
>> that reason I decided to go with "glob" and its GNU extension,
>> GLOB_TILDE. With the import of the "glob" module from gnulib, this is
>> a no-brainer.
>>
>> gdb/ChangeLog:
>> yyyy-mm-dd Sergio Durigan Junior <sergiodj@redhat.com>
>>
>> * Makefile.in (SFILES): Add gdb_chdir.c.
>> (HFILES_NO_SRCDIR): Add gdb_chdir.h.
>> (COMMON_OBS): Add gdb_chdir.o.
>> * cli/cli-cmds.c: Include "gdb_chdir.h".
>> (cd_command): Use "gdb_chdir" instead of "tilde_expand
>> plus chdir".
>> * common/gdb_chdir.c: New file.
>> * common/gdb_chdir.h: Likewise.
>>
>> gdb/gdbserver/ChangeLog:
>> yyyy-mm-dd Sergio Durigan Junior <sergiodj@redhat.com>
>>
>> * Makefile.in (SFILES): Add $(srcdir)/common/gdb_chdir.c.
>> (OBS): Add gdb_chdir.o.
>> ---
>> gdb/Makefile.in | 3 ++
>> gdb/cli/cli-cmds.c | 20 +++++-----
>> gdb/common/gdb_chdir.c | 96 +++++++++++++++++++++++++++++++++++++++++++++++
>> gdb/common/gdb_chdir.h | 26 +++++++++++++
>> gdb/gdbserver/Makefile.in | 2 +
>> 5 files changed, 136 insertions(+), 11 deletions(-)
>> create mode 100644 gdb/common/gdb_chdir.c
>> create mode 100644 gdb/common/gdb_chdir.h
>>
>> diff --git a/gdb/Makefile.in b/gdb/Makefile.in
>> index 9dfc117b2f..1f093e6c0f 100644
>> --- a/gdb/Makefile.in
>> +++ b/gdb/Makefile.in
>> @@ -1245,6 +1245,7 @@ SFILES = \
>> common/filestuff.c \
>> common/format.c \
>> common/job-control.c \
>> + common/gdb_chdir.c \
>> common/gdb_vecs.c \
>> common/new-op.c \
>> common/print-utils.c \
>> @@ -1529,6 +1530,7 @@ HFILES_NO_SRCDIR = \
>> common/fileio.h \
>> common/format.h \
>> common/gdb_assert.h \
>> + common/gdb_chdir.h \
>> common/gdb_locale.h \
>> common/gdb_setjmp.h \
>> common/gdb_signals.h \
>> @@ -1734,6 +1736,7 @@ COMMON_OBS = $(DEPFILES) $(CONFIG_OBS) $(YYOBJ) \
>> frame-unwind.o \
>> gcore.o \
>> gdb_bfd.o \
>> + gdb_chdir.o \
>> gdb-dlfcn.o \
>> gdb_obstack.o \
>> gdb_regex.o \
>> diff --git a/gdb/cli/cli-cmds.c b/gdb/cli/cli-cmds.c
>> index 85d6d21113..653dd56a64 100644
>> --- a/gdb/cli/cli-cmds.c
>> +++ b/gdb/cli/cli-cmds.c
>> @@ -54,6 +54,8 @@
>> #include "tui/tui.h" /* For tui_active et.al. */
>> #endif
>>
>> +#include "gdb_chdir.h"
>> +
>> #include <fcntl.h>
>> #include <algorithm>
>> #include <string>
>> @@ -408,12 +410,7 @@ cd_command (char *dir, int from_tty)
>> repeat might be useful but is more likely to be a mistake. */
>> dont_repeat ();
>>
>> - gdb::unique_xmalloc_ptr<char> dir_holder
>> - (tilde_expand (dir != NULL ? dir : "~"));
>> - dir = dir_holder.get ();
>> -
>> - if (chdir (dir) < 0)
>> - perror_with_name (dir);
>> + gdb_chdir (dir != NULL ? dir : "~");
>>
>> #ifdef HAVE_DOS_BASED_FILE_SYSTEM
>> /* There's too much mess with DOSish names like "d:", "d:.",
>> @@ -436,20 +433,21 @@ cd_command (char *dir, int from_tty)
>> len--;
>> }
>>
>> - dir_holder.reset (savestring (dir, len));
>> - if (IS_ABSOLUTE_PATH (dir_holder.get ()))
>> + std::string newdir = std::string (dir, len);
>> + const char *newdir_str = newdir.c_str ();
>> + if (IS_ABSOLUTE_PATH (newdir_str))
>> {
>> xfree (current_directory);
>> - current_directory = dir_holder.release ();
>> + current_directory = xstrdup (newdir_str);
>
> This introduces one extra deep string dup. One to
> construct the std::string, and another here in this xstrdup.
>
> How about simply, above:
>
> - dir_holder.reset (savestring (dir, len));
> + gdb::unique_xmalloc_ptr<char> dir_holder (savestring (dir, len))
>
>
> But more importantly, isn't there a behavior change here?
> Before, current_directory would be a copy of the the expand
> path, while after the patch, it's a copy of the input string,
> before expansion. Right?
Wow, you're right. I am sorry about letting this slip. I guess I made
so many modifications to this code that in the end I forgot that "dir"
wasn't being updated to hold the expanded path anymore. I will fix
this.
And with your review of patch #4, it is clear that we don't need
a gdb_chdir; we need a gdb_tilde_expand. Therefore I will make the
necessary modifications to export that function instead.
>
>> }
>> else
>> {
>> if (IS_DIR_SEPARATOR (current_directory[strlen (current_directory) - 1]))
>> - current_directory = concat (current_directory, dir_holder.get (),
>> + current_directory = concat (current_directory, newdir_str,
>> (char *) NULL);
>> else
>> current_directory = concat (current_directory, SLASH_STRING,
>> - dir_holder.get (), (char *) NULL);
>> + newdir_str, (char *) NULL);
>> }
>
>
>> + /* Destroy the object and free M_GLOB. */
>> + ~gdb_glob ()
>> + {
>> + globfree (&m_glob);
>> + }
>> +
>> + /* Return the GL_PATHC component of M_GLOB. */
>> + int
>> + pathc () const
>> + {
>> + return m_glob.gl_pathc;
>> + }
>
> We've been putting type and function name in the
> same line in inline member functions. That's the
> de facto standard in GCC as well, AFAICS.
Done.
>
>> +
>> + /* Return the GL_PATHV component of M_GLOB. */
>> + char **
>> + pathv () const
>> + {
>> + return m_glob.gl_pathv;
>> + }
>
> Ditto.
Done.
>
>> +#ifndef HAVE_GDB_CHDIR_H
>> +#define HAVE_GDB_CHDIR_H
>> +
>> +/* Perform a "chdir" to DIR, doing the proper tilde expansion before. */
>> +extern void gdb_chdir (const char *dir);
>
> Nit, I'd drop "the proper", as it doesn't see to add value.
> I.e., what's proper and what's not proper?
Done.
Thanks,
@@ -1245,6 +1245,7 @@ SFILES = \
common/filestuff.c \
common/format.c \
common/job-control.c \
+ common/gdb_chdir.c \
common/gdb_vecs.c \
common/new-op.c \
common/print-utils.c \
@@ -1529,6 +1530,7 @@ HFILES_NO_SRCDIR = \
common/fileio.h \
common/format.h \
common/gdb_assert.h \
+ common/gdb_chdir.h \
common/gdb_locale.h \
common/gdb_setjmp.h \
common/gdb_signals.h \
@@ -1734,6 +1736,7 @@ COMMON_OBS = $(DEPFILES) $(CONFIG_OBS) $(YYOBJ) \
frame-unwind.o \
gcore.o \
gdb_bfd.o \
+ gdb_chdir.o \
gdb-dlfcn.o \
gdb_obstack.o \
gdb_regex.o \
@@ -54,6 +54,8 @@
#include "tui/tui.h" /* For tui_active et.al. */
#endif
+#include "gdb_chdir.h"
+
#include <fcntl.h>
#include <algorithm>
#include <string>
@@ -408,12 +410,7 @@ cd_command (char *dir, int from_tty)
repeat might be useful but is more likely to be a mistake. */
dont_repeat ();
- gdb::unique_xmalloc_ptr<char> dir_holder
- (tilde_expand (dir != NULL ? dir : "~"));
- dir = dir_holder.get ();
-
- if (chdir (dir) < 0)
- perror_with_name (dir);
+ gdb_chdir (dir != NULL ? dir : "~");
#ifdef HAVE_DOS_BASED_FILE_SYSTEM
/* There's too much mess with DOSish names like "d:", "d:.",
@@ -436,20 +433,21 @@ cd_command (char *dir, int from_tty)
len--;
}
- dir_holder.reset (savestring (dir, len));
- if (IS_ABSOLUTE_PATH (dir_holder.get ()))
+ std::string newdir = std::string (dir, len);
+ const char *newdir_str = newdir.c_str ();
+ if (IS_ABSOLUTE_PATH (newdir_str))
{
xfree (current_directory);
- current_directory = dir_holder.release ();
+ current_directory = xstrdup (newdir_str);
}
else
{
if (IS_DIR_SEPARATOR (current_directory[strlen (current_directory) - 1]))
- current_directory = concat (current_directory, dir_holder.get (),
+ current_directory = concat (current_directory, newdir_str,
(char *) NULL);
else
current_directory = concat (current_directory, SLASH_STRING,
- dir_holder.get (), (char *) NULL);
+ newdir_str, (char *) NULL);
}
/* Now simplify any occurrences of `.' and `..' in the pathname. */
new file mode 100644
@@ -0,0 +1,96 @@
+/* chdir(2) wrapper for GDB and gdbserver.
+
+ Copyright (C) 2017 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 "gdb_chdir.h"
+#include <glob.h>
+
+/* RAII-style class wrapping "glob". */
+
+class gdb_glob
+{
+public:
+ /* Construct a "gdb_glob" object by calling "glob" with the provided
+ parameters. This function can throw if "glob" fails. */
+ gdb_glob (const char *pattern, int flags,
+ int (*errfunc) (const char *epath, int eerrno))
+ {
+ int ret = glob (pattern, flags, errfunc, &m_glob);
+
+ if (ret != 0)
+ {
+ if (ret == GLOB_NOMATCH)
+ error (_("Could not find a match for '%s'."), pattern);
+ else
+ error (_("glob could not process pattern '%s'."),
+ pattern);
+ }
+ }
+
+ /* Destroy the object and free M_GLOB. */
+ ~gdb_glob ()
+ {
+ globfree (&m_glob);
+ }
+
+ /* Return the GL_PATHC component of M_GLOB. */
+ int
+ pathc () const
+ {
+ return m_glob.gl_pathc;
+ }
+
+ /* Return the GL_PATHV component of M_GLOB. */
+ char **
+ pathv () const
+ {
+ return m_glob.gl_pathv;
+ }
+
+private:
+ /* The actual glob object we're dealing with. */
+ glob_t m_glob;
+};
+
+/* Perform path expansion (i.e., tilde expansion) on DIR, and return
+ the full path. */
+
+static std::string
+gdb_tilde_expand (const char *dir)
+{
+ gdb_glob glob (dir, GLOB_TILDE | GLOB_TILDE_CHECK | GLOB_ONLYDIR, NULL);
+
+ gdb_assert (glob.pathc () > 0);
+ /* "glob" may return more than one match to the path provided by the
+ user, but we are only interested in the first match. */
+ std::string expanded_dir = glob.pathv ()[0];
+
+ return expanded_dir;
+}
+
+/* See gdb_chdir.h. */
+
+void
+gdb_chdir (const char *dir)
+{
+ std::string expanded_dir = gdb_tilde_expand (dir);
+
+ if (chdir (expanded_dir.c_str ()) < 0)
+ perror_with_name (expanded_dir.c_str ());
+}
new file mode 100644
@@ -0,0 +1,26 @@
+/* chdir(2) wrapper for GDB and gdbserver.
+
+ Copyright (C) 2017 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 HAVE_GDB_CHDIR_H
+#define HAVE_GDB_CHDIR_H
+
+/* Perform a "chdir" to DIR, doing the proper tilde expansion before. */
+extern void gdb_chdir (const char *dir);
+
+#endif /* ! HAVE_GDB_CHDIR_H */
@@ -205,6 +205,7 @@ SFILES = \
$(srcdir)/common/fileio.c \
$(srcdir)/common/filestuff.c \
$(srcdir)/common/job-control.c \
+ $(srcdir)/common/gdb_chdir.c \
$(srcdir)/common/gdb_vecs.c \
$(srcdir)/common/new-op.c \
$(srcdir)/common/print-utils.c \
@@ -247,6 +248,7 @@ OBS = \
fileio.o \
filestuff.o \
format.o \
+ gdb_chdir.o \
gdb_vecs.o \
hostio.o \
inferiors.o \