binutils-gdb/gdb/serial.c
Simon Marchi e0700ba44c gdb: make string-like set show commands use std::string variable
String-like settings (var_string, var_filename, var_optional_filename,
var_string_noescape) currently take a pointer to a `char *` storage
variable (typically global) that holds the setting's value.  I'd like to
"mordernize" this by changing them to use an std::string for storage.

An obvious reason is that string operations on std::string are often
easier to write than with C strings.  And they avoid having to do any
manual memory management.

Another interesting reason is that, with `char *`, nullptr and an empty
string often both have the same meaning of "no value".  String settings
are initially nullptr (unless initialized otherwise).  But when doing
"set foo" (where `foo` is a string setting), the setting now points to
an empty string.  For example, solib_search_path is nullptr at startup,
but points to an empty string after doing "set solib-search-path".  This
leads to some code that needs to check for both to check for "no value".
Or some code that converts back and forth between NULL and "" when
getting or setting the value.  I find this very error-prone, because it
is very easy to forget one or the other.  With std::string, we at least
know that the variable is not "NULL".  There is only one way of
representing an empty string setting, that is with an empty string.

I was wondering whether the distinction between NULL and "" would be
important for some setting, but it doesn't seem so.  If that ever
happens, it would be more C++-y and self-descriptive to use
optional<string> anyway.

Actually, there's one spot where this distinction mattered, it's in
init_history, for the test gdb.base/gdbinit-history.exp.  init_history
sets the history filename to the default ".gdb_history" if it sees that
the setting was never set - if history_filename is nullptr.  If
history_filename is an empty string, it means the setting was explicitly
cleared, so it leaves it as-is.  With the change to std::string, this
distinction doesn't exist anymore.  This can be fixed by moving the code
that chooses a good default value for history_filename to
_initialize_top.  This is ran before -ex commands are processed, so an
-ex command can then clear that value if needed (what
gdb.base/gdbinit-history.exp tests).

Another small improvement, in my opinion is that we can now easily
give string parameters initial values, by simply initializing the global
variables, instead of xstrdup-ing it in the _initialize function.

In Python and Guile, when registering a string-like parameter, we
allocate (with new) an std::string that is owned by the param_smob (in
Guile) and the parmpy_object (in Python) objects.

This patch started by changing all relevant add_setshow_* commands to
take an `std::string *` instead of a `char **` and fixing everything
that failed to build.  That includes of course all string setting
variable and their uses.

string_option_def now uses an std::string also, because there's a
connection between options and settings (see
add_setshow_cmds_for_options).

The add_path function in source.c is really complex and twisted, I'd
rather not try to change it to work on an std::string right now.
Instead, I added an overload that copies the std:string to a `char *`
and back.  This means more copying, but this is not used in a hot path
at all, so I think it is acceptable.

Change-Id: I92c50a1bdd8307141cdbacb388248e4e4fc08c93
Co-authored-by: Lancelot SIX <lsix@lancelotsix.com>
2021-10-03 17:53:16 +01:00

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/* Generic serial interface routines
Copyright (C) 1992-2021 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 "defs.h"
#include <ctype.h>
#include "serial.h"
#include "gdbcmd.h"
#include "cli/cli-utils.h"
/* Is serial being debugged? */
static unsigned int global_serial_debug_p;
/* Serial I/O handlers. */
static std::vector<const struct serial_ops *> serial_ops_list;
/* Pointer to list of scb's. */
static struct serial *scb_base;
/* Non-NULL gives filename which contains a recording of the remote session,
suitable for playback by gdbserver. */
static std::string serial_logfile;
static struct ui_file *serial_logfp = NULL;
static const struct serial_ops *serial_interface_lookup (const char *);
static void serial_logchar (struct ui_file *stream,
int ch_type, int ch, int timeout);
static const char logbase_hex[] = "hex";
static const char logbase_octal[] = "octal";
static const char logbase_ascii[] = "ascii";
static const char *const logbase_enums[] =
{logbase_hex, logbase_octal, logbase_ascii, NULL};
static const char *serial_logbase = logbase_ascii;
static int serial_current_type = 0;
/* Log char CH of type CHTYPE, with TIMEOUT. */
/* Define bogus char to represent a BREAK. Should be careful to choose a value
that can't be confused with a normal char, or an error code. */
#define SERIAL_BREAK 1235
static void
serial_logchar (struct ui_file *stream, int ch_type, int ch, int timeout)
{
if (ch_type != serial_current_type)
{
fprintf_unfiltered (stream, "\n%c ", ch_type);
serial_current_type = ch_type;
}
if (serial_logbase != logbase_ascii)
fputc_unfiltered (' ', stream);
switch (ch)
{
case SERIAL_TIMEOUT:
fprintf_unfiltered (stream, "<Timeout: %d seconds>", timeout);
return;
case SERIAL_ERROR:
fprintf_unfiltered (stream, "<Error: %s>", safe_strerror (errno));
return;
case SERIAL_EOF:
fputs_unfiltered ("<Eof>", stream);
return;
case SERIAL_BREAK:
fputs_unfiltered ("<Break>", stream);
return;
default:
if (serial_logbase == logbase_hex)
fprintf_unfiltered (stream, "%02x", ch & 0xff);
else if (serial_logbase == logbase_octal)
fprintf_unfiltered (stream, "%03o", ch & 0xff);
else
switch (ch)
{
case '\\':
fputs_unfiltered ("\\\\", stream);
break;
case '\b':
fputs_unfiltered ("\\b", stream);
break;
case '\f':
fputs_unfiltered ("\\f", stream);
break;
case '\n':
fputs_unfiltered ("\\n", stream);
break;
case '\r':
fputs_unfiltered ("\\r", stream);
break;
case '\t':
fputs_unfiltered ("\\t", stream);
break;
case '\v':
fputs_unfiltered ("\\v", stream);
break;
default:
fprintf_unfiltered (stream,
isprint (ch) ? "%c" : "\\x%02x", ch & 0xFF);
break;
}
}
}
void
serial_log_command (struct target_ops *self, const char *cmd)
{
if (!serial_logfp)
return;
serial_current_type = 'c';
fputs_unfiltered ("\nc ", serial_logfp);
fputs_unfiltered (cmd, serial_logfp);
/* Make sure that the log file is as up-to-date as possible,
in case we are getting ready to dump core or something. */
gdb_flush (serial_logfp);
}
static const struct serial_ops *
serial_interface_lookup (const char *name)
{
for (const serial_ops *ops : serial_ops_list)
if (strcmp (name, ops->name) == 0)
return ops;
return NULL;
}
void
serial_add_interface (const struct serial_ops *optable)
{
serial_ops_list.push_back (optable);
}
/* Return the open serial device for FD, if found, or NULL if FD is
not already opened. */
struct serial *
serial_for_fd (int fd)
{
struct serial *scb;
for (scb = scb_base; scb; scb = scb->next)
if (scb->fd == fd)
return scb;
return NULL;
}
/* Create a new serial for OPS. */
static struct serial *
new_serial (const struct serial_ops *ops)
{
struct serial *scb;
scb = XCNEW (struct serial);
scb->ops = ops;
scb->bufp = scb->buf;
scb->error_fd = -1;
scb->refcnt = 1;
return scb;
}
static struct serial *serial_open_ops_1 (const struct serial_ops *ops,
const char *open_name);
/* Open up a device or a network socket, depending upon the syntax of NAME. */
struct serial *
serial_open (const char *name)
{
const struct serial_ops *ops;
const char *open_name = name;
if (startswith (name, "|"))
{
ops = serial_interface_lookup ("pipe");
/* Discard ``|'' and any space before the command itself. */
++open_name;
open_name = skip_spaces (open_name);
}
/* Check for a colon, suggesting an IP address/port pair.
Do this *after* checking for all the interesting prefixes. We
don't want to constrain the syntax of what can follow them. */
else if (strchr (name, ':'))
ops = serial_interface_lookup ("tcp");
else
{
#ifndef USE_WIN32API
/* Check to see if name is a socket. If it is, then treat it
as such. Otherwise assume that it's a character device. */
struct stat sb;
if (stat (name, &sb) == 0 && (sb.st_mode & S_IFMT) == S_IFSOCK)
ops = serial_interface_lookup ("local");
else
#endif
ops = serial_interface_lookup ("hardwire");
}
if (!ops)
return NULL;
return serial_open_ops_1 (ops, open_name);
}
/* Open up a serial for OPS, passing OPEN_NAME to the open method. */
static struct serial *
serial_open_ops_1 (const struct serial_ops *ops, const char *open_name)
{
struct serial *scb;
scb = new_serial (ops);
/* `...->open (...)' would get expanded by the open(2) syscall macro. */
if ((*scb->ops->open) (scb, open_name))
{
xfree (scb);
return NULL;
}
scb->name = open_name != NULL ? xstrdup (open_name) : NULL;
scb->next = scb_base;
scb_base = scb;
if (!serial_logfile.empty ())
{
stdio_file_up file (new stdio_file ());
if (!file->open (serial_logfile.c_str (), "w"))
perror_with_name (serial_logfile.c_str ());
serial_logfp = file.release ();
}
return scb;
}
/* See serial.h. */
struct serial *
serial_open_ops (const struct serial_ops *ops)
{
return serial_open_ops_1 (ops, NULL);
}
/* Open a new serial stream using a file handle, using serial
interface ops OPS. */
static struct serial *
serial_fdopen_ops (const int fd, const struct serial_ops *ops)
{
struct serial *scb;
if (!ops)
{
ops = serial_interface_lookup ("terminal");
if (!ops)
ops = serial_interface_lookup ("hardwire");
}
if (!ops)
return NULL;
scb = new_serial (ops);
scb->name = NULL;
scb->next = scb_base;
scb_base = scb;
if ((ops->fdopen) != NULL)
(*ops->fdopen) (scb, fd);
else
scb->fd = fd;
return scb;
}
struct serial *
serial_fdopen (const int fd)
{
return serial_fdopen_ops (fd, NULL);
}
static void
do_serial_close (struct serial *scb, int really_close)
{
struct serial *tmp_scb;
if (serial_logfp)
{
fputs_unfiltered ("\nEnd of log\n", serial_logfp);
serial_current_type = 0;
/* XXX - What if serial_logfp == gdb_stdout or gdb_stderr? */
delete serial_logfp;
serial_logfp = NULL;
}
/* ensure that the FD has been taken out of async mode. */
if (scb->async_handler != NULL)
serial_async (scb, NULL, NULL);
if (really_close)
scb->ops->close (scb);
xfree (scb->name);
/* For serial_is_open. */
scb->bufp = NULL;
if (scb_base == scb)
scb_base = scb_base->next;
else
for (tmp_scb = scb_base; tmp_scb; tmp_scb = tmp_scb->next)
{
if (tmp_scb->next != scb)
continue;
tmp_scb->next = tmp_scb->next->next;
break;
}
serial_unref (scb);
}
void
serial_close (struct serial *scb)
{
do_serial_close (scb, 1);
}
void
serial_un_fdopen (struct serial *scb)
{
do_serial_close (scb, 0);
}
int
serial_is_open (struct serial *scb)
{
return scb->bufp != NULL;
}
void
serial_ref (struct serial *scb)
{
scb->refcnt++;
}
void
serial_unref (struct serial *scb)
{
--scb->refcnt;
if (scb->refcnt == 0)
xfree (scb);
}
int
serial_readchar (struct serial *scb, int timeout)
{
int ch;
/* FIXME: cagney/1999-10-11: Don't enable this check until the ASYNC
code is finished. */
if (0 && serial_is_async_p (scb) && timeout < 0)
internal_error (__FILE__, __LINE__,
_("serial_readchar: blocking read in async mode"));
ch = scb->ops->readchar (scb, timeout);
if (serial_logfp != NULL)
{
serial_logchar (serial_logfp, 'r', ch, timeout);
/* Make sure that the log file is as up-to-date as possible,
in case we are getting ready to dump core or something. */
gdb_flush (serial_logfp);
}
if (serial_debug_p (scb))
{
fprintf_unfiltered (gdb_stdlog, "[");
serial_logchar (gdb_stdlog, 'r', ch, timeout);
fprintf_unfiltered (gdb_stdlog, "]");
gdb_flush (gdb_stdlog);
}
return (ch);
}
int
serial_write (struct serial *scb, const void *buf, size_t count)
{
if (serial_logfp != NULL)
{
const char *str = (const char *) buf;
size_t c;
for (c = 0; c < count; c++)
serial_logchar (serial_logfp, 'w', str[c] & 0xff, 0);
/* Make sure that the log file is as up-to-date as possible,
in case we are getting ready to dump core or something. */
gdb_flush (serial_logfp);
}
if (serial_debug_p (scb))
{
const char *str = (const char *) buf;
size_t c;
for (c = 0; c < count; c++)
{
fprintf_unfiltered (gdb_stdlog, "[");
serial_logchar (gdb_stdlog, 'w', str[c] & 0xff, 0);
fprintf_unfiltered (gdb_stdlog, "]");
}
gdb_flush (gdb_stdlog);
}
return (scb->ops->write (scb, buf, count));
}
void
serial_printf (struct serial *desc, const char *format, ...)
{
va_list args;
va_start (args, format);
std::string buf = string_vprintf (format, args);
serial_write (desc, buf.c_str (), buf.length ());
va_end (args);
}
int
serial_drain_output (struct serial *scb)
{
return scb->ops->drain_output (scb);
}
int
serial_flush_output (struct serial *scb)
{
return scb->ops->flush_output (scb);
}
int
serial_flush_input (struct serial *scb)
{
return scb->ops->flush_input (scb);
}
int
serial_send_break (struct serial *scb)
{
if (serial_logfp != NULL)
serial_logchar (serial_logfp, 'w', SERIAL_BREAK, 0);
return (scb->ops->send_break (scb));
}
void
serial_raw (struct serial *scb)
{
scb->ops->go_raw (scb);
}
serial_ttystate
serial_get_tty_state (struct serial *scb)
{
return scb->ops->get_tty_state (scb);
}
serial_ttystate
serial_copy_tty_state (struct serial *scb, serial_ttystate ttystate)
{
return scb->ops->copy_tty_state (scb, ttystate);
}
int
serial_set_tty_state (struct serial *scb, serial_ttystate ttystate)
{
return scb->ops->set_tty_state (scb, ttystate);
}
void
serial_print_tty_state (struct serial *scb,
serial_ttystate ttystate,
struct ui_file *stream)
{
scb->ops->print_tty_state (scb, ttystate, stream);
}
int
serial_setbaudrate (struct serial *scb, int rate)
{
return scb->ops->setbaudrate (scb, rate);
}
int
serial_setstopbits (struct serial *scb, int num)
{
return scb->ops->setstopbits (scb, num);
}
/* See serial.h. */
int
serial_setparity (struct serial *scb, int parity)
{
return scb->ops->setparity (scb, parity);
}
int
serial_can_async_p (struct serial *scb)
{
return (scb->ops->async != NULL);
}
int
serial_is_async_p (struct serial *scb)
{
return (scb->ops->async != NULL) && (scb->async_handler != NULL);
}
void
serial_async (struct serial *scb,
serial_event_ftype *handler,
void *context)
{
int changed = ((scb->async_handler == NULL) != (handler == NULL));
scb->async_handler = handler;
scb->async_context = context;
/* Only change mode if there is a need. */
if (changed)
scb->ops->async (scb, handler != NULL);
}
void
serial_debug (struct serial *scb, int debug_p)
{
scb->debug_p = debug_p;
}
int
serial_debug_p (struct serial *scb)
{
return scb->debug_p || global_serial_debug_p;
}
#ifdef USE_WIN32API
void
serial_wait_handle (struct serial *scb, HANDLE *read, HANDLE *except)
{
if (scb->ops->wait_handle)
scb->ops->wait_handle (scb, read, except);
else
{
*read = (HANDLE) _get_osfhandle (scb->fd);
*except = NULL;
}
}
void
serial_done_wait_handle (struct serial *scb)
{
if (scb->ops->done_wait_handle)
scb->ops->done_wait_handle (scb);
}
#endif
int
serial_pipe (struct serial *scbs[2])
{
const struct serial_ops *ops;
int fildes[2];
ops = serial_interface_lookup ("pipe");
if (!ops)
{
errno = ENOSYS;
return -1;
}
if (gdb_pipe (fildes) == -1)
return -1;
scbs[0] = serial_fdopen_ops (fildes[0], ops);
scbs[1] = serial_fdopen_ops (fildes[1], ops);
return 0;
}
/* Serial set/show framework. */
static struct cmd_list_element *serial_set_cmdlist;
static struct cmd_list_element *serial_show_cmdlist;
/* See serial.h. */
int baud_rate = -1;
static void
serial_baud_show_cmd (struct ui_file *file, int from_tty,
struct cmd_list_element *c, const char *value)
{
fprintf_filtered (file, _("Baud rate for remote serial I/O is %s.\n"),
value);
}
/* See serial.h. */
int serial_parity = GDBPARITY_NONE;
static const char parity_none[] = "none";
static const char parity_odd[] = "odd";
static const char parity_even[] = "even";
static const char *const parity_enums[] =
{parity_none, parity_odd, parity_even, NULL};
static const char *parity = parity_none;
/* Set serial_parity value. */
static void
set_parity (const char *ignore_args, int from_tty, struct cmd_list_element *c)
{
if (parity == parity_odd)
serial_parity = GDBPARITY_ODD;
else if (parity == parity_even)
serial_parity = GDBPARITY_EVEN;
else
serial_parity = GDBPARITY_NONE;
}
void _initialize_serial ();
void
_initialize_serial ()
{
#if 0
add_com ("connect", class_obscure, connect_command, _("\
Connect the terminal directly up to the command monitor.\n\
Use <CR>~. or <CR>~^D to break out."));
#endif /* 0 */
add_basic_prefix_cmd ("serial", class_maintenance, _("\
Set default serial/parallel port configuration."),
&serial_set_cmdlist,
0/*allow-unknown*/,
&setlist);
add_show_prefix_cmd ("serial", class_maintenance, _("\
Show default serial/parallel port configuration."),
&serial_show_cmdlist,
0/*allow-unknown*/,
&showlist);
/* If target is open when baud changes, it doesn't take effect until
the next open (I think, not sure). */
add_setshow_zinteger_cmd ("baud", no_class, &baud_rate, _("\
Set baud rate for remote serial I/O."), _("\
Show baud rate for remote serial I/O."), _("\
This value is used to set the speed of the serial port when debugging\n\
using remote targets."),
NULL,
serial_baud_show_cmd,
&serial_set_cmdlist, &serial_show_cmdlist);
add_setshow_enum_cmd ("parity", no_class, parity_enums,
&parity, _("\
Set parity for remote serial I/O."), _("\
Show parity for remote serial I/O."), NULL,
set_parity,
NULL, /* FIXME: i18n: */
&serial_set_cmdlist, &serial_show_cmdlist);
add_setshow_filename_cmd ("remotelogfile", no_class, &serial_logfile, _("\
Set filename for remote session recording."), _("\
Show filename for remote session recording."), _("\
This file is used to record the remote session for future playback\n\
by gdbserver."),
NULL,
NULL, /* FIXME: i18n: */
&setlist, &showlist);
add_setshow_enum_cmd ("remotelogbase", no_class, logbase_enums,
&serial_logbase, _("\
Set numerical base for remote session logging."), _("\
Show numerical base for remote session logging."), NULL,
NULL,
NULL, /* FIXME: i18n: */
&setlist, &showlist);
add_setshow_zuinteger_cmd ("serial", class_maintenance,
&global_serial_debug_p, _("\
Set serial debugging."), _("\
Show serial debugging."), _("\
When non-zero, serial port debugging is enabled."),
NULL,
NULL, /* FIXME: i18n: */
&setdebuglist, &showdebuglist);
}