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binutils-gdb/gdb/mingw-hdep.c
Bernhard Wodok 16d01f9cd4 Fix PR win32/24284: tcp_auto_retry doesn't work in MinGW
This was reported by Bernhard Wodok, along with a patch to fix the
issue.  I adjusted the patch a bit, and I'm submitting the patch on
his behalf.

According to Bernhard, the issue can be reproduced by doing:

  1. start gdb
  2. enter 'target remote :2345'
  3. observe that it throws a "connection refused" error immediately
  instead of waiting and throwing a timeout error

I.e., I believe it can be reproduced by our current tests, which is
why I'm not proposing any extra tests here (well, I don't use nor have
any Windows system to test this, so...).

The problem happens because, on ser-tcp:wait_for_connect, we call
'gdb_select' passing 0 as its first argument, which, when using MinGW,
ends up using the 'gdb_select' version from mingw-hdep.c, and when the
first argument is 0 this means that WaitForMultipleObjects will be
called with 0 as its first argument as well.  According to the MS API
docs, this is forbidden:

  https://docs.microsoft.com/en-us/windows/win32/api/synchapi/nf-synchapi-waitformultipleobjects

The proposed fix is simple: we just call Sleep when N == 0 (and when
TIMEOUT is non-NULL), and return 0.  It makes sense to me.

Both Bernhard and Paul Carroll confirmed that the fix works.  I'm
Cc'ing Bernhard in case you have any questions about the patch.

OK?

gdb/ChangeLog:
2019-08-29  Bernhard Wodok  <barto@gmx.net>
	    Sergio Durigan Junior  <sergiodj@redhat.com>

	PR win32/24284
	* mingw-hdep.c (gdb_select): Handle case when 'n' is zero.
2019-08-29 12:35:58 -04:00

374 lines
10 KiB
C

/* Host support routines for MinGW, for GDB, the GNU debugger.
Copyright (C) 2006-2019 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 "main.h"
#include "serial.h"
#include "event-loop.h"
#include "gdb_select.h"
#include <windows.h>
/* Return an absolute file name of the running GDB, if possible, or
ARGV0 if not. The return value is in malloc'ed storage. */
char *
windows_get_absolute_argv0 (const char *argv0)
{
char full_name[PATH_MAX];
if (GetModuleFileName (NULL, full_name, PATH_MAX))
return xstrdup (full_name);
return xstrdup (argv0);
}
/* Wrapper for select. On Windows systems, where the select interface
only works for sockets, this uses the GDB serial abstraction to
handle sockets, consoles, pipes, and serial ports.
The arguments to this function are the same as the traditional
arguments to select on POSIX platforms. */
int
gdb_select (int n, fd_set *readfds, fd_set *writefds, fd_set *exceptfds,
struct timeval *timeout)
{
static HANDLE never_handle;
HANDLE handles[MAXIMUM_WAIT_OBJECTS];
HANDLE h;
DWORD event;
DWORD num_handles;
/* SCBS contains serial control objects corresponding to file
descriptors in READFDS and WRITEFDS. */
struct serial *scbs[MAXIMUM_WAIT_OBJECTS];
/* The number of valid entries in SCBS. */
size_t num_scbs;
int fd;
int num_ready;
size_t indx;
if (n == 0)
{
/* The MS API says that the first argument to
WaitForMultipleObjects cannot be zero. That's why we just
use a regular Sleep here. */
if (timeout != NULL)
Sleep (timeout->tv_sec * 1000 + timeout->tv_usec / 1000);
return 0;
}
num_ready = 0;
num_handles = 0;
num_scbs = 0;
for (fd = 0; fd < n; ++fd)
{
HANDLE read = NULL, except = NULL;
struct serial *scb;
/* There is no support yet for WRITEFDS. At present, this isn't
used by GDB -- but we do not want to silently ignore WRITEFDS
if something starts using it. */
gdb_assert (!writefds || !FD_ISSET (fd, writefds));
if ((!readfds || !FD_ISSET (fd, readfds))
&& (!exceptfds || !FD_ISSET (fd, exceptfds)))
continue;
scb = serial_for_fd (fd);
if (scb)
{
serial_wait_handle (scb, &read, &except);
scbs[num_scbs++] = scb;
}
if (read == NULL)
read = (HANDLE) _get_osfhandle (fd);
if (except == NULL)
{
if (!never_handle)
never_handle = CreateEvent (0, FALSE, FALSE, 0);
except = never_handle;
}
if (readfds && FD_ISSET (fd, readfds))
{
gdb_assert (num_handles < MAXIMUM_WAIT_OBJECTS);
handles[num_handles++] = read;
}
if (exceptfds && FD_ISSET (fd, exceptfds))
{
gdb_assert (num_handles < MAXIMUM_WAIT_OBJECTS);
handles[num_handles++] = except;
}
}
gdb_assert (num_handles <= MAXIMUM_WAIT_OBJECTS);
event = WaitForMultipleObjects (num_handles,
handles,
FALSE,
timeout
? (timeout->tv_sec * 1000
+ timeout->tv_usec / 1000)
: INFINITE);
/* EVENT can only be a value in the WAIT_ABANDONED_0 range if the
HANDLES included an abandoned mutex. Since GDB doesn't use
mutexes, that should never occur. */
gdb_assert (!(WAIT_ABANDONED_0 <= event
&& event < WAIT_ABANDONED_0 + num_handles));
/* We no longer need the helper threads to check for activity. */
for (indx = 0; indx < num_scbs; ++indx)
serial_done_wait_handle (scbs[indx]);
if (event == WAIT_FAILED)
return -1;
if (event == WAIT_TIMEOUT)
return 0;
/* Run through the READFDS, clearing bits corresponding to descriptors
for which input is unavailable. */
h = handles[event - WAIT_OBJECT_0];
for (fd = 0, indx = 0; fd < n; ++fd)
{
HANDLE fd_h;
if ((!readfds || !FD_ISSET (fd, readfds))
&& (!exceptfds || !FD_ISSET (fd, exceptfds)))
continue;
if (readfds && FD_ISSET (fd, readfds))
{
fd_h = handles[indx++];
/* This handle might be ready, even though it wasn't the handle
returned by WaitForMultipleObjects. */
if (fd_h != h && WaitForSingleObject (fd_h, 0) != WAIT_OBJECT_0)
FD_CLR (fd, readfds);
else
num_ready++;
}
if (exceptfds && FD_ISSET (fd, exceptfds))
{
fd_h = handles[indx++];
/* This handle might be ready, even though it wasn't the handle
returned by WaitForMultipleObjects. */
if (fd_h != h && WaitForSingleObject (fd_h, 0) != WAIT_OBJECT_0)
FD_CLR (fd, exceptfds);
else
num_ready++;
}
}
return num_ready;
}
/* Map COLOR's RGB triplet, with 8 bits per component, into 16 Windows
console colors, where each component has just 1 bit, plus a single
intensity bit which affects all 3 components. */
static int
rgb_to_16colors (const ui_file_style::color &color)
{
uint8_t rgb[3];
color.get_rgb (rgb);
int retval = 0;
for (int i = 0; i < 3; i++)
{
/* Subdivide 256 possible values of each RGB component into 3
regions: no color, normal color, bright color. 256 / 3 = 85,
but ui-style.c follows xterm and uses 92 for R and G
components of the bright-blue color, so we bias the divisor a
bit to have the bright colors between 9 and 15 identical to
what ui-style.c expects. */
int bits = rgb[i] / 93;
retval |= ((bits > 0) << (2 - i)) | ((bits > 1) << 3);
}
return retval;
}
/* Zero if not yet initialized, 1 if stdout is a console device, else -1. */
static int mingw_console_initialized;
/* Handle to stdout . */
static HANDLE hstdout = INVALID_HANDLE_VALUE;
/* Text attribute to use for normal text (the "none" pseudo-color). */
static SHORT norm_attr;
/* The most recently applied style. */
static ui_file_style last_style;
/* Alternative for the libc 'fputs' which handles embedded SGR
sequences in support of styling. */
int
gdb_console_fputs (const char *linebuf, FILE *fstream)
{
if (!mingw_console_initialized)
{
hstdout = (HANDLE)_get_osfhandle (fileno (fstream));
DWORD cmode;
CONSOLE_SCREEN_BUFFER_INFO csbi;
if (hstdout != INVALID_HANDLE_VALUE
&& GetConsoleMode (hstdout, &cmode) != 0
&& GetConsoleScreenBufferInfo (hstdout, &csbi))
{
norm_attr = csbi.wAttributes;
mingw_console_initialized = 1;
}
else if (hstdout != INVALID_HANDLE_VALUE)
mingw_console_initialized = -1; /* valid, but not a console device */
}
/* If our stdout is not a console device, let the default 'fputs'
handle the task. */
if (mingw_console_initialized <= 0)
return 0;
/* Mapping between 8 ANSI colors and Windows console attributes. */
static int fg_color[] = {
0, /* black */
FOREGROUND_RED, /* red */
FOREGROUND_GREEN, /* green */
FOREGROUND_GREEN | FOREGROUND_RED, /* yellow */
FOREGROUND_BLUE, /* blue */
FOREGROUND_BLUE | FOREGROUND_RED, /* magenta */
FOREGROUND_BLUE | FOREGROUND_GREEN, /* cyan */
FOREGROUND_RED | FOREGROUND_GREEN | FOREGROUND_BLUE /* gray */
};
static int bg_color[] = {
0, /* black */
BACKGROUND_RED, /* red */
BACKGROUND_GREEN, /* green */
BACKGROUND_GREEN | BACKGROUND_RED, /* yellow */
BACKGROUND_BLUE, /* blue */
BACKGROUND_BLUE | BACKGROUND_RED, /* magenta */
BACKGROUND_BLUE | BACKGROUND_GREEN, /* cyan */
BACKGROUND_RED | BACKGROUND_GREEN | BACKGROUND_BLUE /* gray */
};
ui_file_style style = last_style;
unsigned char c;
size_t n_read;
for ( ; (c = *linebuf) != 0; linebuf += n_read)
{
if (c == '\033')
{
fflush (fstream);
bool parsed = style.parse (linebuf, &n_read);
if (n_read <= 0) /* should never happen */
n_read = 1;
if (!parsed)
{
/* This means we silently swallow SGR sequences we
cannot parse. */
continue;
}
/* Colors. */
const ui_file_style::color &fg = style.get_foreground ();
const ui_file_style::color &bg = style.get_background ();
int fgcolor, bgcolor, bright, inverse;
if (fg.is_none ())
fgcolor = norm_attr & 15;
else if (fg.is_basic ())
fgcolor = fg_color[fg.get_value () & 15];
else
fgcolor = rgb_to_16colors (fg);
if (bg.is_none ())
bgcolor = norm_attr & (15 << 4);
else if (bg.is_basic ())
bgcolor = bg_color[bg.get_value () & 15];
else
bgcolor = rgb_to_16colors (bg) << 4;
/* Intensity. */
switch (style.get_intensity ())
{
case ui_file_style::NORMAL:
case ui_file_style::DIM:
bright = 0;
break;
case ui_file_style::BOLD:
bright = 1;
break;
default:
gdb_assert_not_reached ("invalid intensity");
}
/* Inverse video. */
if (style.is_reverse ())
inverse = 1;
else
inverse = 0;
/* Construct the attribute. */
if (inverse)
{
int t = fgcolor;
fgcolor = (bgcolor >> 4);
bgcolor = (t << 4);
}
if (bright)
fgcolor |= FOREGROUND_INTENSITY;
SHORT attr = (bgcolor & (15 << 4)) | (fgcolor & 15);
/* Apply the attribute. */
SetConsoleTextAttribute (hstdout, attr);
}
else
{
/* When we are about to write newline, we need to clear to
EOL with the normal attribute, to avoid spilling the
colors to the next screen line. We assume here that no
non-default attribute extends beyond the newline. */
if (c == '\n')
{
DWORD nchars;
COORD start_pos;
DWORD written;
CONSOLE_SCREEN_BUFFER_INFO csbi;
fflush (fstream);
GetConsoleScreenBufferInfo (hstdout, &csbi);
if (csbi.wAttributes != norm_attr)
{
start_pos = csbi.dwCursorPosition;
nchars = csbi.dwSize.X - start_pos.X;
FillConsoleOutputAttribute (hstdout, norm_attr, nchars,
start_pos, &written);
FillConsoleOutputCharacter (hstdout, ' ', nchars,
start_pos, &written);
}
}
fputc (c, fstream);
n_read = 1;
}
}
last_style = style;
return 1;
}