| 1 | /* Host support routines for MinGW, for GDB, the GNU debugger. |
| 2 | |
| 3 | Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011 |
| 4 | Free Software Foundation, Inc. |
| 5 | |
| 6 | This file is part of GDB. |
| 7 | |
| 8 | This program is free software; you can redistribute it and/or modify |
| 9 | it under the terms of the GNU General Public License as published by |
| 10 | the Free Software Foundation; either version 3 of the License, or |
| 11 | (at your option) any later version. |
| 12 | |
| 13 | This program is distributed in the hope that it will be useful, |
| 14 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 16 | GNU General Public License for more details. |
| 17 | |
| 18 | You should have received a copy of the GNU General Public License |
| 19 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ |
| 20 | |
| 21 | #include "defs.h" |
| 22 | #include "serial.h" |
| 23 | #include "event-loop.h" |
| 24 | |
| 25 | #include "gdb_assert.h" |
| 26 | #include "gdb_select.h" |
| 27 | #include "gdb_string.h" |
| 28 | #include "readline/readline.h" |
| 29 | |
| 30 | #include <windows.h> |
| 31 | |
| 32 | /* This event is signalled whenever an asynchronous SIGINT handler |
| 33 | needs to perform an action in the main thread. */ |
| 34 | static HANDLE sigint_event; |
| 35 | |
| 36 | /* When SIGINT_EVENT is signalled, gdb_select will call this |
| 37 | function. */ |
| 38 | struct async_signal_handler *sigint_handler; |
| 39 | |
| 40 | /* The strerror() function can return NULL for errno values that are |
| 41 | out of range. Provide a "safe" version that always returns a |
| 42 | printable string. |
| 43 | |
| 44 | The Windows runtime implementation of strerror never returns NULL, |
| 45 | but does return a useless string for anything above sys_nerr; |
| 46 | unfortunately this includes all socket-related error codes. |
| 47 | This replacement tries to find a system-provided error message. */ |
| 48 | |
| 49 | char * |
| 50 | safe_strerror (int errnum) |
| 51 | { |
| 52 | static char *buffer; |
| 53 | int len; |
| 54 | |
| 55 | if (errnum >= 0 && errnum < sys_nerr) |
| 56 | return strerror (errnum); |
| 57 | |
| 58 | if (buffer) |
| 59 | { |
| 60 | LocalFree (buffer); |
| 61 | buffer = NULL; |
| 62 | } |
| 63 | |
| 64 | if (FormatMessage (FORMAT_MESSAGE_ALLOCATE_BUFFER |
| 65 | | FORMAT_MESSAGE_FROM_SYSTEM, |
| 66 | NULL, errnum, |
| 67 | MAKELANGID (LANG_NEUTRAL, SUBLANG_DEFAULT), |
| 68 | (LPTSTR) &buffer, 0, NULL) == 0) |
| 69 | { |
| 70 | static char buf[32]; |
| 71 | xsnprintf (buf, sizeof buf, "(undocumented errno %d)", errnum); |
| 72 | return buf; |
| 73 | } |
| 74 | |
| 75 | /* Windows error messages end with a period and a CR-LF; strip that |
| 76 | out. */ |
| 77 | len = strlen (buffer); |
| 78 | if (len > 3 && strcmp (buffer + len - 3, ".\r\n") == 0) |
| 79 | buffer[len - 3] = '\0'; |
| 80 | |
| 81 | return buffer; |
| 82 | } |
| 83 | |
| 84 | /* Wrapper for select. On Windows systems, where the select interface |
| 85 | only works for sockets, this uses the GDB serial abstraction to |
| 86 | handle sockets, consoles, pipes, and serial ports. |
| 87 | |
| 88 | The arguments to this function are the same as the traditional |
| 89 | arguments to select on POSIX platforms. */ |
| 90 | |
| 91 | int |
| 92 | gdb_select (int n, fd_set *readfds, fd_set *writefds, fd_set *exceptfds, |
| 93 | struct timeval *timeout) |
| 94 | { |
| 95 | static HANDLE never_handle; |
| 96 | HANDLE handles[MAXIMUM_WAIT_OBJECTS]; |
| 97 | HANDLE h; |
| 98 | DWORD event; |
| 99 | DWORD num_handles; |
| 100 | /* SCBS contains serial control objects corresponding to file |
| 101 | descriptors in READFDS and WRITEFDS. */ |
| 102 | struct serial *scbs[MAXIMUM_WAIT_OBJECTS]; |
| 103 | /* The number of valid entries in SCBS. */ |
| 104 | size_t num_scbs; |
| 105 | int fd; |
| 106 | int num_ready; |
| 107 | size_t indx; |
| 108 | |
| 109 | num_ready = 0; |
| 110 | num_handles = 0; |
| 111 | num_scbs = 0; |
| 112 | for (fd = 0; fd < n; ++fd) |
| 113 | { |
| 114 | HANDLE read = NULL, except = NULL; |
| 115 | struct serial *scb; |
| 116 | |
| 117 | /* There is no support yet for WRITEFDS. At present, this isn't |
| 118 | used by GDB -- but we do not want to silently ignore WRITEFDS |
| 119 | if something starts using it. */ |
| 120 | gdb_assert (!writefds || !FD_ISSET (fd, writefds)); |
| 121 | |
| 122 | if ((!readfds || !FD_ISSET (fd, readfds)) |
| 123 | && (!exceptfds || !FD_ISSET (fd, exceptfds))) |
| 124 | continue; |
| 125 | |
| 126 | scb = serial_for_fd (fd); |
| 127 | if (scb) |
| 128 | { |
| 129 | serial_wait_handle (scb, &read, &except); |
| 130 | scbs[num_scbs++] = scb; |
| 131 | } |
| 132 | |
| 133 | if (read == NULL) |
| 134 | read = (HANDLE) _get_osfhandle (fd); |
| 135 | if (except == NULL) |
| 136 | { |
| 137 | if (!never_handle) |
| 138 | never_handle = CreateEvent (0, FALSE, FALSE, 0); |
| 139 | |
| 140 | except = never_handle; |
| 141 | } |
| 142 | |
| 143 | if (readfds && FD_ISSET (fd, readfds)) |
| 144 | { |
| 145 | gdb_assert (num_handles < MAXIMUM_WAIT_OBJECTS); |
| 146 | handles[num_handles++] = read; |
| 147 | } |
| 148 | |
| 149 | if (exceptfds && FD_ISSET (fd, exceptfds)) |
| 150 | { |
| 151 | gdb_assert (num_handles < MAXIMUM_WAIT_OBJECTS); |
| 152 | handles[num_handles++] = except; |
| 153 | } |
| 154 | } |
| 155 | |
| 156 | gdb_assert (num_handles < MAXIMUM_WAIT_OBJECTS); |
| 157 | handles[num_handles++] = sigint_event; |
| 158 | |
| 159 | event = WaitForMultipleObjects (num_handles, |
| 160 | handles, |
| 161 | FALSE, |
| 162 | timeout |
| 163 | ? (timeout->tv_sec * 1000 |
| 164 | + timeout->tv_usec / 1000) |
| 165 | : INFINITE); |
| 166 | /* EVENT can only be a value in the WAIT_ABANDONED_0 range if the |
| 167 | HANDLES included an abandoned mutex. Since GDB doesn't use |
| 168 | mutexes, that should never occur. */ |
| 169 | gdb_assert (!(WAIT_ABANDONED_0 <= event |
| 170 | && event < WAIT_ABANDONED_0 + num_handles)); |
| 171 | /* We no longer need the helper threads to check for activity. */ |
| 172 | for (indx = 0; indx < num_scbs; ++indx) |
| 173 | serial_done_wait_handle (scbs[indx]); |
| 174 | if (event == WAIT_FAILED) |
| 175 | return -1; |
| 176 | if (event == WAIT_TIMEOUT) |
| 177 | return 0; |
| 178 | /* Run through the READFDS, clearing bits corresponding to descriptors |
| 179 | for which input is unavailable. */ |
| 180 | h = handles[event - WAIT_OBJECT_0]; |
| 181 | for (fd = 0, indx = 0; fd < n; ++fd) |
| 182 | { |
| 183 | HANDLE fd_h; |
| 184 | |
| 185 | if ((!readfds || !FD_ISSET (fd, readfds)) |
| 186 | && (!exceptfds || !FD_ISSET (fd, exceptfds))) |
| 187 | continue; |
| 188 | |
| 189 | if (readfds && FD_ISSET (fd, readfds)) |
| 190 | { |
| 191 | fd_h = handles[indx++]; |
| 192 | /* This handle might be ready, even though it wasn't the handle |
| 193 | returned by WaitForMultipleObjects. */ |
| 194 | if (fd_h != h && WaitForSingleObject (fd_h, 0) != WAIT_OBJECT_0) |
| 195 | FD_CLR (fd, readfds); |
| 196 | else |
| 197 | num_ready++; |
| 198 | } |
| 199 | |
| 200 | if (exceptfds && FD_ISSET (fd, exceptfds)) |
| 201 | { |
| 202 | fd_h = handles[indx++]; |
| 203 | /* This handle might be ready, even though it wasn't the handle |
| 204 | returned by WaitForMultipleObjects. */ |
| 205 | if (fd_h != h && WaitForSingleObject (fd_h, 0) != WAIT_OBJECT_0) |
| 206 | FD_CLR (fd, exceptfds); |
| 207 | else |
| 208 | num_ready++; |
| 209 | } |
| 210 | } |
| 211 | |
| 212 | /* With multi-threaded SIGINT handling, there is a race between the |
| 213 | readline signal handler and GDB. It may still be in |
| 214 | rl_prep_terminal in another thread. Do not return until it is |
| 215 | done; we can check the state here because we never longjmp from |
| 216 | signal handlers on Windows. */ |
| 217 | while (RL_ISSTATE (RL_STATE_SIGHANDLER)) |
| 218 | Sleep (1); |
| 219 | |
| 220 | if (h == sigint_event |
| 221 | || WaitForSingleObject (sigint_event, 0) == WAIT_OBJECT_0) |
| 222 | { |
| 223 | if (sigint_handler != NULL) |
| 224 | call_async_signal_handler (sigint_handler); |
| 225 | |
| 226 | if (num_ready == 0) |
| 227 | { |
| 228 | errno = EINTR; |
| 229 | return -1; |
| 230 | } |
| 231 | } |
| 232 | |
| 233 | return num_ready; |
| 234 | } |
| 235 | |
| 236 | /* Wrapper for the body of signal handlers. On Windows systems, a |
| 237 | SIGINT handler runs in its own thread. We can't longjmp from |
| 238 | there, and we shouldn't even prompt the user. Delay HANDLER |
| 239 | until the main thread is next in gdb_select. */ |
| 240 | |
| 241 | void |
| 242 | gdb_call_async_signal_handler (struct async_signal_handler *handler, |
| 243 | int immediate_p) |
| 244 | { |
| 245 | if (immediate_p) |
| 246 | sigint_handler = handler; |
| 247 | else |
| 248 | { |
| 249 | mark_async_signal_handler (handler); |
| 250 | sigint_handler = NULL; |
| 251 | } |
| 252 | SetEvent (sigint_event); |
| 253 | } |
| 254 | |
| 255 | void |
| 256 | _initialize_mingw_hdep (void) |
| 257 | { |
| 258 | sigint_event = CreateEvent (0, FALSE, FALSE, 0); |
| 259 | } |