Re: [PATCH] Move "tee" building down to interpreter::set_logging_proc

Pedro Alves
2017-02-02T22:12:53Z

On 02/02/2017 08:42 PM, Simon Marchi wrote:
> On 2017-02-02 13:04, Pedro Alves wrote:
>> How about this?
> LGTM!

Many thanks for the review! I've pushed it in now, as below.
(Added a missing "the".)

From 616268b639780e0819b51053c794037bcde3de16 Mon Sep 17 00:00:00 2001
From: Pedro Alves <palves@redhat.com>
Date: Thu, 2 Feb 2017 22:00:43 +0000
Subject: [PATCH] Move "tee" building down to interpreter::set_logging_proc

This patch gets rid of this hack in mi_set_logging:

/* The tee created already is based on gdb_stdout, which for MI
is a console and so we end up in an infinite loop of console
writing to ui_file writing to console etc. So discard the
existing tee (it hasn't been used yet, and MI won't ever use
it), and create one based on raw_stdout instead. */

By pushing down responsibility for the tee creation to the
interpreter. I.e., pushing the CLI bits out of handle_redirections
down to the CLI interpreter's set_logging_proc method.

This fixes a few leaks that I spotted, and then confirmed with
"valgrind --leak-check=full":

[...]
==21429== 56 (32 direct, 24 indirect) bytes in 1 blocks are definitely lost in loss record 30,243 of 34,980
==21429== at 0x4C29216: operator new(unsigned long) (vg_replace_malloc.c:334)
==21429== by 0x62D9A9: mi_set_logging(interp*, int, ui_file*, ui_file*) (mi-interp.c:1395)
==21429== by 0x810B8A: current_interp_set_logging(int, ui_file*, ui_file*) (interps.c:360)
==21429== by 0x61C537: handle_redirections(int) (cli-logging.c:162)
==21429== by 0x61C6EC: set_logging_on(char*, int) (cli-logging.c:190)
==21429== by 0x6163BE: do_cfunc(cmd_list_element*, char*, int) (cli-decode.c:105)
==21429== by 0x6193C1: cmd_func(cmd_list_element*, char*, int) (cli-decode.c:1913)
==21429== by 0x8DB790: execute_command(char*, int) (top.c:674)
==21429== by 0x632AE6: mi_execute_cli_command(char const*, int, char const*) (mi-main.c:2343)
==21429== by 0x6329BA: mi_cmd_execute(mi_parse*) (mi-main.c:2306)
==21429== by 0x631E19: captured_mi_execute_command(ui_out*, mi_parse*) (mi-main.c:1998)
==21429== by 0x632389: mi_execute_command(char const*, int) (mi-main.c:2163)
==21429==
[...]
==26635== 24 bytes in 1 blocks are definitely lost in loss record 20,740 of 34,995
==26635== at 0x4C29216: operator new(unsigned long) (vg_replace_malloc.c:334)
==26635== by 0x61C355: handle_redirections(int) (cli-logging.c:131)
==26635== by 0x61C6EC: set_logging_on(char*, int) (cli-logging.c:190)
==26635== by 0x6163BE: do_cfunc(cmd_list_element*, char*, int) (cli-decode.c:105)
==26635== by 0x6193C1: cmd_func(cmd_list_element*, char*, int) (cli-decode.c:1913)
==26635== by 0x8DB7BC: execute_command(char*, int) (top.c:674)
==26635== by 0x7B9132: command_handler(char*) (event-top.c:590)
==26635== by 0x7B94F7: command_line_handler(char*) (event-top.c:780)
==26635== by 0x7B8ABB: gdb_rl_callback_handler(char*) (event-top.c:213)
==26635== by 0x933CE9: rl_callback_read_char (callback.c:220)
==26635== by 0x7B89ED: gdb_rl_callback_read_char_wrapper_noexcept() (event-top.c:175)
==26635== by 0x7B8A49: gdb_rl_callback_read_char_wrapper(void*) (event-top.c:192)

One is fixed by transfering ownership of the log file to the tee. In
pseudo-patch, since the code was moved at the same time:

- out = new tee_file (curr_output, false, logfile.get (), false);
+ out = new tee_file (curr_output, false, logfile.get (), true);

The other is this bit in mi_set_logging:

else
{
+ delete mi->raw_stdout;

I tried to split the leak fixes to a smaller preparatory patch, but
that was difficult exactly because of the tee hack in
handle_redirections -> mi_set_logging.

gdb/ChangeLog:
2017-02-02 Pedro Alves <palves@redhat.com>

* cli/cli-interp.c (struct saved_output_files, saved_output):
Moved from cli/cli-logging.c.
(cli_set_logging): New function.
(cli_interp_procs): Install cli_set_logging.
* cli/cli-interp.h (make_logging_output, cli_set_logging):
Declare.
* cli/cli-logging.c (struct saved_output_files, saved_output):
Moved to cli/cli-interp.c.
(pop_output_files): Don't save outputs here.
(make_logging_output): New function.
(handle_redirections): Don't build tee nor save previous outputs
here.
* interps.c (current_interp_set_logging): Change prototype.
Assume there's always a set_logging_proc method installed.
* interps.h (interp_set_logging_ftype): Change prototype.
(current_interp_set_logging): Change prototype and adjust comment.
* mi/mi-interp.c (mi_set_logging): Change protototype. Adjust to
use make_logging_output.
* tui/tui-interp.c (tui_interp_procs): Install cli_set_logging.
---
gdb/ChangeLog | 21 ++++++++++++
gdb/cli/cli-interp.c | 59 ++++++++++++++++++++++++++++++++-
gdb/cli/cli-interp.h | 18 ++++++++++
gdb/cli/cli-logging.c | 92 +++++++++++++++++----------------------------------
gdb/interps.c | 13 +++-----
gdb/interps.h | 22 ++++++------
gdb/mi/mi-interp.c | 30 ++++++-----------
gdb/tui/tui-interp.c | 2 +-
8 files changed, 155 insertions(+), 102 deletions(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index df5238c..fbbcc07 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,26 @@
2017-02-02 Pedro Alves <palves@redhat.com>

+ * cli/cli-interp.c (struct saved_output_files, saved_output):
+ Moved from cli/cli-logging.c.
+ (cli_set_logging): New function.
+ (cli_interp_procs): Install cli_set_logging.
+ * cli/cli-interp.h (make_logging_output, cli_set_logging):
+ Declare.
+ * cli/cli-logging.c (struct saved_output_files, saved_output):
+ Moved to cli/cli-interp.c.
+ (pop_output_files): Don't save outputs here.
+ (make_logging_output): New function.
+ (handle_redirections): Don't build tee nor save previous outputs
+ here.
+ * interps.c (current_interp_set_logging): Change prototype.
+ Assume there's always a set_logging_proc method installed.
+ * interps.h (interp_set_logging_ftype): Change prototype.
+ (current_interp_set_logging): Change prototype and adjust comment.
+ * mi/mi-interp.c (mi_set_logging): Change protototype. Adjust to
+ use make_logging_output.
+ * tui/tui-interp.c (tui_interp_procs): Install cli_set_logging.
+2017-02-02 Pedro Alves <palves@redhat.com>
+
* cli/cli-logging.c (maybe_warn_already_logging): New factored out
from ...
(set_logging_overwrite): ... here.
diff --git a/gdb/cli/cli-interp.c b/gdb/cli/cli-interp.c
index 8802a5a..e0327f6 100644
--- a/gdb/cli/cli-interp.c
+++ b/gdb/cli/cli-interp.c
@@ -373,6 +373,63 @@ cli_ui_out (struct interp *self)
return cli->cli_uiout;
}

+/* These hold the pushed copies of the gdb output files.
+ If NULL then nothing has yet been pushed. */
+struct saved_output_files
+{
+ ui_file *out;
+ ui_file *err;
+ ui_file *log;
+ ui_file *targ;
+ ui_file *targerr;
+};
+static saved_output_files saved_output;
+
+/* See cli-interp.h. */
+
+void
+cli_set_logging (struct interp *interp,
+ ui_file_up logfile, bool logging_redirect)
+{
+ if (logfile != NULL)
+ {
+ saved_output.out = gdb_stdout;
+ saved_output.err = gdb_stderr;
+ saved_output.log = gdb_stdlog;
+ saved_output.targ = gdb_stdtarg;
+ saved_output.targerr = gdb_stdtargerr;
+
+ /* A raw pointer since ownership is transferred to
+ gdb_stdout. */
+ ui_file *output = make_logging_output (gdb_stdout,
+ std::move (logfile),
+ logging_redirect);
+ gdb_stdout = output;
+ gdb_stdlog = output;
+ gdb_stderr = output;
+ gdb_stdtarg = output;
+ gdb_stdtargerr = output;
+ }
+ else
+ {
+ /* Only delete one of the files -- they are all set to the same
+ value. */
+ delete gdb_stdout;
+
+ gdb_stdout = saved_output.out;
+ gdb_stderr = saved_output.err;
+ gdb_stdlog = saved_output.log;
+ gdb_stdtarg = saved_output.targ;
+ gdb_stdtargerr = saved_output.targerr;
+
+ saved_output.out = NULL;
+ saved_output.err = NULL;
+ saved_output.log = NULL;
+ saved_output.targ = NULL;
+ saved_output.targerr = NULL;
+ }
+}
+
/* The CLI interpreter's vtable. */

static const struct interp_procs cli_interp_procs = {
@@ -381,7 +438,7 @@ static const struct interp_procs cli_interp_procs = {
cli_interpreter_suspend, /* suspend_proc */
cli_interpreter_exec, /* exec_proc */
cli_ui_out, /* ui_out_proc */
- NULL, /* set_logging_proc */
+ cli_set_logging, /* set_logging_proc */
cli_interpreter_pre_command_loop, /* pre_command_loop_proc */
cli_interpreter_supports_command_editing, /* supports_command_editing_proc */
};
diff --git a/gdb/cli/cli-interp.h b/gdb/cli/cli-interp.h
index ef86372..f93548c 100644
--- a/gdb/cli/cli-interp.h
+++ b/gdb/cli/cli-interp.h
@@ -20,6 +20,24 @@

struct interp;

+/* Make the output ui_file to use when logging is enabled.
+ CURR_OUTPUT is the stream where output is currently being sent to
+ (e.g., gdb_stdout for the CLI, raw output stream for the MI).
+ LOGFILE is the log file already opened by the caller.
+ LOGGING_REDIRECT is the value of the "set logging redirect"
+ setting. If true, the resulting output is the logfile. If false,
+ the output stream is a tee, with the log file as one of the
+ outputs. Ownership of LOGFILE is transferred to the returned
+ output file, which is an owning pointer. */
+extern ui_file *make_logging_output (ui_file *curr_output,
+ ui_file_up logfile,
+ bool logging_redirect);
+
+/* The CLI interpreter's set_logging_proc method. Exported so other
+ interpreters can reuse it. */
+extern void cli_set_logging (struct interp *interp,
+ ui_file_up logfile, bool logging_redirect);
+
extern int cli_interpreter_supports_command_editing (struct interp *interp);

extern void cli_interpreter_pre_command_loop (struct interp *self);
diff --git a/gdb/cli/cli-logging.c b/gdb/cli/cli-logging.c
index edb8313..e8ec444 100644
--- a/gdb/cli/cli-logging.c
+++ b/gdb/cli/cli-logging.c
@@ -22,17 +22,6 @@
#include "ui-out.h"
#include "interps.h"

-/* These hold the pushed copies of the gdb output files.
- If NULL then nothing has yet been pushed. */
-struct saved_output_files
-{
- struct ui_file *out;
- struct ui_file *err;
- struct ui_file *log;
- struct ui_file *targ;
- struct ui_file *targerr;
-};
-static struct saved_output_files saved_output;
static char *saved_filename;

static char *logging_filename;
@@ -90,37 +79,35 @@ show_logging_redirect (struct ui_file *file, int from_tty,
static void
pop_output_files (void)
{
- if (current_interp_set_logging (0, NULL, NULL) == 0)
- {
- /* Only delete one of the files -- they are all set to the same
- value. */
- delete gdb_stdout;
-
- gdb_stdout = saved_output.out;
- gdb_stderr = saved_output.err;
- gdb_stdlog = saved_output.log;
- gdb_stdtarg = saved_output.targ;
- gdb_stdtargerr = saved_output.targerr;
- }
-
- saved_output.out = NULL;
- saved_output.err = NULL;
- saved_output.log = NULL;
- saved_output.targ = NULL;
- saved_output.targerr = NULL;
+ current_interp_set_logging (NULL, false);

/* Stay consistent with handle_redirections. */
if (!current_uiout->is_mi_like_p ())
current_uiout->redirect (NULL);
}

+/* See cli-interp.h. */
+
+ui_file *
+make_logging_output (ui_file *curr_output, ui_file_up logfile,
+ bool logging_redirect)
+{
+ if (logging_redirect)
+ return logfile.release ();
+ else
+ {
+ /* Note that the "tee" takes ownership of the log file. */
+ ui_file *out = new tee_file (curr_output, false,
+ logfile.get (), true);
+ logfile.release ();
+ return out;
+ }
+}
+
/* This is a helper for the `set logging' command. */
static void
handle_redirections (int from_tty)
{
- ui_file_up output;
- ui_file_up no_redirect_file;
-
if (saved_filename != NULL)
{
fprintf_unfiltered (gdb_stdout, "Already logging to %s.\n",
@@ -133,46 +120,27 @@ handle_redirections (int from_tty)
perror_with_name (_("set logging"));

/* Redirects everything to gdb_stdout while this is running. */
- if (!logging_redirect)
+ if (from_tty)
{
- no_redirect_file = std::move (log);
- output.reset (new tee_file (gdb_stdout, 0, no_redirect_file.get (), 0));
-
- if (from_tty)
+ if (!logging_redirect)
fprintf_unfiltered (gdb_stdout, "Copying output to %s.\n",
logging_filename);
- }
- else
- {
- output = std::move (log);
-
- if (from_tty)
+ else
fprintf_unfiltered (gdb_stdout, "Redirecting output to %s.\n",
logging_filename);
}

saved_filename = xstrdup (logging_filename);
- saved_output.out = gdb_stdout;
- saved_output.err = gdb_stderr;
- saved_output.log = gdb_stdlog;
- saved_output.targ = gdb_stdtarg;
- saved_output.targerr = gdb_stdtargerr;

/* Let the interpreter do anything it needs. */
- if (current_interp_set_logging (1, output.get (),
- no_redirect_file.get ()) == 0)
- {
- gdb_stdout = output.get ();
- gdb_stdlog = output.get ();
- gdb_stderr = output.get ();
- gdb_stdtarg = output.get ();
- gdb_stdtargerr = output.get ();
- }
-
- output.release ();
- no_redirect_file.release ();
-
- /* Don't do the redirect for MI, it confuses MI's ui-out scheme. */
+ current_interp_set_logging (std::move (log), logging_redirect);
+
+ /* Redirect the current ui-out object's output to the log. Use
+ gdb_stdout, not log, since the interpreter may have created a tee
+ that wraps the log. Don't do the redirect for MI, it confuses
+ MI's ui-out scheme. Note that we may get here with MI as current
+ interpreter, but with the current ui_out as a CLI ui_out, with
+ '-interpreter-exec console "set logging on"'. */
if (!current_uiout->is_mi_like_p ())
current_uiout->redirect (gdb_stdout);
}
diff --git a/gdb/interps.c b/gdb/interps.c
index a2b7ffe..06e7ccf 100644
--- a/gdb/interps.c
+++ b/gdb/interps.c
@@ -346,18 +346,15 @@ interp_ui_out (struct interp *interp)
return interp->procs->ui_out_proc (interp);
}

-int
-current_interp_set_logging (int start_log, struct ui_file *out,
- struct ui_file *logfile)
+void
+current_interp_set_logging (ui_file_up logfile,
+ bool logging_redirect)
{
struct ui_interp_info *ui_interp = get_current_interp_info ();
struct interp *interp = ui_interp->current_interpreter;

- if (interp == NULL
- || interp->procs->set_logging_proc == NULL)
- return 0;
-
- return interp->procs->set_logging_proc (interp, start_log, out, logfile);
+ return interp->procs->set_logging_proc (interp, std::move (logfile),
+ logging_redirect);
}

/* Temporarily overrides the current interpreter. */
diff --git a/gdb/interps.h b/gdb/interps.h
index 5ec2b05..ef2ceeb 100644
--- a/gdb/interps.h
+++ b/gdb/interps.h
@@ -49,9 +49,9 @@ typedef struct gdb_exception (interp_exec_ftype) (void *data,
typedef void (interp_pre_command_loop_ftype) (struct interp *self);
typedef struct ui_out *(interp_ui_out_ftype) (struct interp *self);

-typedef int (interp_set_logging_ftype) (struct interp *self, int start_log,
- struct ui_file *out,
- struct ui_file *logfile);
+typedef void (interp_set_logging_ftype) (struct interp *self,
+ ui_file_up logfile,
+ bool logging_redirect);

typedef int (interp_supports_command_editing_ftype) (struct interp *self);

@@ -109,13 +109,15 @@ extern int current_interp_named_p (const char *name);

/* Call this function to give the current interpreter an opportunity
to do any special handling of streams when logging is enabled or
- disabled. START_LOG is 1 when logging is starting, 0 when it ends,
- and OUT is the stream for the log file; it will be NULL when
- logging is ending. LOGFILE is non-NULL if the output streams
- are to be tees, with the log file as one of the outputs. */
-
-extern int current_interp_set_logging (int start_log, struct ui_file *out,
- struct ui_file *logfile);
+ disabled. LOGFILE is the stream for the log file when logging is
+ starting and is NULL when logging is ending. LOGGING_REDIRECT is
+ the value of the "set logging redirect" setting. If true, the
+ interpreter should configure the output streams to send output only
+ to the logfile. If false, the interpreter should configure the
+ output streams to send output to both the current output stream
+ (i.e., the terminal) and the log file. */
+extern void current_interp_set_logging (ui_file_up logfile,
+ bool logging_redirect);

/* Returns opaque data associated with the top-level interpreter. */
extern void *top_level_interpreter_data (void);
diff --git a/gdb/mi/mi-interp.c b/gdb/mi/mi-interp.c
index f167a53..aa76989 100644
--- a/gdb/mi/mi-interp.c
+++ b/gdb/mi/mi-interp.c
@@ -1373,33 +1373,25 @@ mi_ui_out (struct interp *interp)
/* Do MI-specific logging actions; save raw_stdout, and change all
the consoles to use the supplied ui-file(s). */

-static int
-mi_set_logging (struct interp *interp, int start_log,
- struct ui_file *out, struct ui_file *logfile)
+static void
+mi_set_logging (struct interp *interp,
+ ui_file_up logfile, bool logging_redirect)
{
struct mi_interp *mi = (struct mi_interp *) interp_data (interp);

- if (!mi)
- return 0;
+ gdb_assert (mi != NULL);

- if (start_log)
+ if (logfile != NULL)
{
- /* The tee created already is based on gdb_stdout, which for MI
- is a console and so we end up in an infinite loop of console
- writing to ui_file writing to console etc. So discard the
- existing tee (it hasn't been used yet, and MI won't ever use
- it), and create one based on raw_stdout instead. */
- if (logfile)
- {
- delete out;
- out = new tee_file (mi->raw_stdout, false, logfile, false);
- }
-
mi->saved_raw_stdout = mi->raw_stdout;
- mi->raw_stdout = out;
+ mi->raw_stdout = make_logging_output (mi->raw_stdout,
+ std::move (logfile),
+ logging_redirect);
+
}
else
{
+ delete mi->raw_stdout;
mi->raw_stdout = mi->saved_raw_stdout;
mi->saved_raw_stdout = NULL;
}
@@ -1409,8 +1401,6 @@ mi_set_logging (struct interp *interp, int start_log,
mi->log->set_raw (mi->raw_stdout);
mi->targ->set_raw (mi->raw_stdout);
mi->event_channel->set_raw (mi->raw_stdout);
-
- return 1;
}

/* The MI interpreter's vtable. */
diff --git a/gdb/tui/tui-interp.c b/gdb/tui/tui-interp.c
index 7893904..e2c0605 100644
--- a/gdb/tui/tui-interp.c
+++ b/gdb/tui/tui-interp.c
@@ -302,7 +302,7 @@ static const struct interp_procs tui_interp_procs = {
tui_suspend,
tui_exec,
tui_ui_out,
- NULL,
+ cli_set_logging,
cli_interpreter_pre_command_loop,
cli_interpreter_supports_command_editing,
};
--
2.5.5