| /*********************************************************** |
| Copyright 1991-1995 by Stichting Mathematisch Centrum, Amsterdam, |
| The Netherlands. |
| |
| All Rights Reserved |
| |
| Permission to use, copy, modify, and distribute this software and its |
| documentation for any purpose and without fee is hereby granted, |
| provided that the above copyright notice appear in all copies and that |
| both that copyright notice and this permission notice appear in |
| supporting documentation, and that the names of Stichting Mathematisch |
| Centrum or CWI or Corporation for National Research Initiatives or |
| CNRI not be used in advertising or publicity pertaining to |
| distribution of the software without specific, written prior |
| permission. |
| |
| While CWI is the initial source for this software, a modified version |
| is made available by the Corporation for National Research Initiatives |
| (CNRI) at the Internet address ftp://ftp.python.org. |
| |
| STICHTING MATHEMATISCH CENTRUM AND CNRI DISCLAIM ALL WARRANTIES WITH |
| REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF |
| MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH |
| CENTRUM OR CNRI BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL |
| DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR |
| PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER |
| TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR |
| PERFORMANCE OF THIS SOFTWARE. |
| |
| ******************************************************************/ |
| |
| /* Signal module -- many thanks to Lance Ellinghaus */ |
| |
| /* XXX Signals should be recorded per thread, now we have thread state. */ |
| |
| #include "Python.h" |
| #include "intrcheck.h" |
| |
| #ifdef MS_WIN32 |
| #include <process.h> |
| #endif |
| |
| #ifdef HAVE_UNISTD_H |
| #include <unistd.h> |
| #endif |
| |
| #include <signal.h> |
| |
| #ifndef SIG_ERR |
| #define SIG_ERR ((RETSIGTYPE (*)())-1) |
| #endif |
| |
| #if defined(PYOS_OS2) |
| #define NSIG 12 |
| #include <process.h> |
| #endif |
| |
| #ifndef NSIG |
| #ifdef _SIGMAX |
| #define NSIG (_SIGMAX + 1) /* For QNX */ |
| #else |
| #define NSIG (SIGMAX + 1) /* for djgpp */ |
| #endif |
| #endif |
| |
| |
| |
| /* |
| NOTES ON THE INTERACTION BETWEEN SIGNALS AND THREADS |
| |
| When threads are supported, we want the following semantics: |
| |
| - only the main thread can set a signal handler |
| - any thread can get a signal handler |
| - signals are only delivered to the main thread |
| |
| I.e. we don't support "synchronous signals" like SIGFPE (catching |
| this doesn't make much sense in Python anyway) nor do we support |
| signals as a means of inter-thread communication, since not all |
| thread implementations support that (at least our thread library |
| doesn't). |
| |
| We still have the problem that in some implementations signals |
| generated by the keyboard (e.g. SIGINT) are delivered to all |
| threads (e.g. SGI), while in others (e.g. Solaris) such signals are |
| delivered to one random thread (an intermediate possibility would |
| be to deliver it to the main thread -- POSIX?). For now, we have |
| a working implementation that works in all three cases -- the |
| handler ignores signals if getpid() isn't the same as in the main |
| thread. XXX This is a hack. |
| |
| */ |
| |
| #ifdef WITH_THREAD |
| #include <sys/types.h> /* For pid_t */ |
| #include "pythread.h" |
| static long main_thread; |
| static pid_t main_pid; |
| #endif |
| |
| static struct { |
| int tripped; |
| PyObject *func; |
| } Handlers[NSIG]; |
| |
| static int is_tripped = 0; /* Speed up sigcheck() when none tripped */ |
| |
| static PyObject *DefaultHandler; |
| static PyObject *IgnoreHandler; |
| static PyObject *IntHandler; |
| |
| static RETSIGTYPE (*old_siginthandler)() = SIG_DFL; |
| |
| |
| |
| static PyObject * |
| signal_default_int_handler(self, arg) |
| PyObject *self; |
| PyObject *arg; |
| { |
| PyErr_SetNone(PyExc_KeyboardInterrupt); |
| return NULL; |
| } |
| |
| static char default_int_handler_doc[] = |
| "default_int_handler(...)\n\ |
| \n\ |
| The default handler for SIGINT instated by Python.\n\ |
| It raises KeyboardInterrupt."; |
| |
| |
| static RETSIGTYPE |
| signal_handler(sig_num) |
| int sig_num; |
| { |
| #ifdef WITH_THREAD |
| /* See NOTES section above */ |
| if (getpid() == main_pid) { |
| #endif |
| is_tripped++; |
| Handlers[sig_num].tripped = 1; |
| Py_AddPendingCall( |
| (int (*) Py_PROTO((ANY *)))PyErr_CheckSignals, NULL); |
| #ifdef WITH_THREAD |
| } |
| #endif |
| #ifdef SIGCHLD |
| if (sig_num == SIGCHLD) { |
| /* To avoid infinite recursion, this signal remains |
| reset until explicit re-instated. |
| Don't clear the 'func' field as it is our pointer |
| to the Python handler... */ |
| return; |
| } |
| #endif |
| #ifdef HAVE_SIGINTERRUPT |
| siginterrupt(sig_num, 1); |
| #endif |
| (void)signal(sig_num, &signal_handler); |
| } |
| |
| |
| |
| #ifdef HAVE_ALARM |
| static PyObject * |
| signal_alarm(self, args) |
| PyObject *self; /* Not used */ |
| PyObject *args; |
| { |
| int t; |
| if (!PyArg_Parse(args, "i", &t)) |
| return NULL; |
| /* alarm() returns the number of seconds remaining */ |
| return PyInt_FromLong(alarm(t)); |
| } |
| |
| static char alarm_doc[] = |
| "alarm(seconds)\n\ |
| \n\ |
| Arrange for SIGALRM to arrive after the given number of seconds."; |
| #endif |
| |
| #ifdef HAVE_PAUSE |
| static PyObject * |
| signal_pause(self, args) |
| PyObject *self; /* Not used */ |
| PyObject *args; |
| { |
| if (!PyArg_NoArgs(args)) |
| return NULL; |
| |
| Py_BEGIN_ALLOW_THREADS |
| (void)pause(); |
| Py_END_ALLOW_THREADS |
| /* make sure that any exceptions that got raised are propagated |
| * back into Python |
| */ |
| if (PyErr_CheckSignals()) |
| return NULL; |
| |
| Py_INCREF(Py_None); |
| return Py_None; |
| } |
| static char pause_doc[] = |
| "pause()\n\ |
| \n\ |
| Wait until a signal arrives."; |
| |
| #endif |
| |
| |
| static PyObject * |
| signal_signal(self, args) |
| PyObject *self; /* Not used */ |
| PyObject *args; |
| { |
| PyObject *obj; |
| int sig_num; |
| PyObject *old_handler; |
| RETSIGTYPE (*func)(); |
| if (!PyArg_Parse(args, "(iO)", &sig_num, &obj)) |
| return NULL; |
| #ifdef WITH_THREAD |
| if (get_thread_ident() != main_thread) { |
| PyErr_SetString(PyExc_ValueError, |
| "signal only works in main thread"); |
| return NULL; |
| } |
| #endif |
| if (sig_num < 1 || sig_num >= NSIG) { |
| PyErr_SetString(PyExc_ValueError, |
| "signal number out of range"); |
| return NULL; |
| } |
| if (obj == IgnoreHandler) |
| func = SIG_IGN; |
| else if (obj == DefaultHandler) |
| func = SIG_DFL; |
| else if (!PyCallable_Check(obj)) { |
| PyErr_SetString(PyExc_TypeError, |
| "signal handler must be signal.SIG_IGN, signal.SIG_DFL, or a callable object"); |
| return NULL; |
| } |
| else |
| func = signal_handler; |
| #ifdef HAVE_SIGINTERRUPT |
| siginterrupt(sig_num, 1); |
| #endif |
| if (signal(sig_num, func) == SIG_ERR) { |
| PyErr_SetFromErrno(PyExc_RuntimeError); |
| return NULL; |
| } |
| old_handler = Handlers[sig_num].func; |
| Handlers[sig_num].tripped = 0; |
| Py_INCREF(obj); |
| Handlers[sig_num].func = obj; |
| return old_handler; |
| } |
| |
| static char signal_doc[] = |
| "signal(sig, action) -> action\n\ |
| \n\ |
| Set the action for the given signal. The action can be SIG_DFL,\n\ |
| SIG_IGN, or a callable Python object. The previous action is\n\ |
| returned. See getsignal() for possible return values.\n\ |
| \n\ |
| *** IMPORTANT NOTICE ***\n\ |
| A signal handler function is called with two arguments:\n\ |
| the first is the signal number, the second is the interrupted stack frame."; |
| |
| |
| static PyObject * |
| signal_getsignal(self, args) |
| PyObject *self; /* Not used */ |
| PyObject *args; |
| { |
| int sig_num; |
| PyObject *old_handler; |
| if (!PyArg_Parse(args, "i", &sig_num)) |
| return NULL; |
| if (sig_num < 1 || sig_num >= NSIG) { |
| PyErr_SetString(PyExc_ValueError, |
| "signal number out of range"); |
| return NULL; |
| } |
| old_handler = Handlers[sig_num].func; |
| Py_INCREF(old_handler); |
| return old_handler; |
| } |
| |
| static char getsignal_doc[] = |
| "getsignal(sig) -> action\n\ |
| \n\ |
| Return the current action for the given signal. The return value can be:\n\ |
| SIG_IGN -- if the signal is being ignored\n\ |
| SIG_DFL -- if the default action for the signal is in effect\n\ |
| None -- if an unknown handler is in effect\n\ |
| anything else -- the callable Python object used as a handler\n\ |
| "; |
| |
| |
| /* List of functions defined in the module */ |
| static PyMethodDef signal_methods[] = { |
| #ifdef HAVE_ALARM |
| {"alarm", signal_alarm, 0, alarm_doc}, |
| #endif |
| {"signal", signal_signal, 0, signal_doc}, |
| {"getsignal", signal_getsignal, 0, getsignal_doc}, |
| #ifdef HAVE_PAUSE |
| {"pause", signal_pause, 0, pause_doc}, |
| #endif |
| {"default_int_handler", signal_default_int_handler, 0, |
| default_int_handler_doc}, |
| {NULL, NULL} /* sentinel */ |
| }; |
| |
| |
| |
| static char module_doc[] = |
| "This module provides mechanisms to use signal handlers in Python.\n\ |
| \n\ |
| Functions:\n\ |
| \n\ |
| alarm() -- cause SIGALRM after a specified time [Unix only]\n\ |
| signal() -- set the action for a given signal\n\ |
| getsignal() -- get the signal action for a given signal\n\ |
| pause() -- wait until a signal arrives [Unix only]\n\ |
| default_int_handler() -- default SIGINT handler\n\ |
| \n\ |
| Constants:\n\ |
| \n\ |
| SIG_DFL -- used to refer to the system default handler\n\ |
| SIG_IGN -- used to ignore the signal\n\ |
| NSIG -- number of defined signals\n\ |
| \n\ |
| SIGINT, SIGTERM, etc. -- signal numbers\n\ |
| \n\ |
| *** IMPORTANT NOTICE ***\n\ |
| A signal handler function is called with two arguments:\n\ |
| the first is the signal number, the second is the interrupted stack frame."; |
| |
| void |
| initsignal() |
| { |
| PyObject *m, *d, *x; |
| int i; |
| |
| #ifdef WITH_THREAD |
| main_thread = get_thread_ident(); |
| main_pid = getpid(); |
| #endif |
| |
| /* Create the module and add the functions */ |
| m = Py_InitModule3("signal", signal_methods, module_doc); |
| |
| /* Add some symbolic constants to the module */ |
| d = PyModule_GetDict(m); |
| |
| x = DefaultHandler = PyInt_FromLong((long)SIG_DFL); |
| if (!x || PyDict_SetItemString(d, "SIG_DFL", x) < 0) |
| goto finally; |
| |
| x = IgnoreHandler = PyInt_FromLong((long)SIG_IGN); |
| if (!x || PyDict_SetItemString(d, "SIG_IGN", x) < 0) |
| goto finally; |
| |
| x = PyInt_FromLong((long)NSIG); |
| if (!x || PyDict_SetItemString(d, "NSIG", x) < 0) |
| goto finally; |
| Py_DECREF(x); |
| |
| x = IntHandler = PyDict_GetItemString(d, "default_int_handler"); |
| if (!x) |
| goto finally; |
| Py_INCREF(IntHandler); |
| |
| Handlers[0].tripped = 0; |
| for (i = 1; i < NSIG; i++) { |
| RETSIGTYPE (*t)(); |
| #ifdef HAVE_SIGACTION |
| struct sigaction act; |
| sigaction(i, 0, &act); |
| t = act.sa_handler; |
| #else |
| t = signal(i, SIG_IGN); |
| signal(i, t); |
| #endif |
| Handlers[i].tripped = 0; |
| if (t == SIG_DFL) |
| Handlers[i].func = DefaultHandler; |
| else if (t == SIG_IGN) |
| Handlers[i].func = IgnoreHandler; |
| else |
| Handlers[i].func = Py_None; /* None of our business */ |
| Py_INCREF(Handlers[i].func); |
| } |
| if (Handlers[SIGINT].func == DefaultHandler) { |
| /* Install default int handler */ |
| Py_INCREF(IntHandler); |
| Py_DECREF(Handlers[SIGINT].func); |
| Handlers[SIGINT].func = IntHandler; |
| old_siginthandler = signal(SIGINT, &signal_handler); |
| } |
| |
| #ifdef SIGHUP |
| x = PyInt_FromLong(SIGHUP); |
| PyDict_SetItemString(d, "SIGHUP", x); |
| Py_XDECREF(x); |
| #endif |
| #ifdef SIGINT |
| x = PyInt_FromLong(SIGINT); |
| PyDict_SetItemString(d, "SIGINT", x); |
| Py_XDECREF(x); |
| #endif |
| #ifdef SIGQUIT |
| x = PyInt_FromLong(SIGQUIT); |
| PyDict_SetItemString(d, "SIGQUIT", x); |
| Py_XDECREF(x); |
| #endif |
| #ifdef SIGILL |
| x = PyInt_FromLong(SIGILL); |
| PyDict_SetItemString(d, "SIGILL", x); |
| Py_XDECREF(x); |
| #endif |
| #ifdef SIGTRAP |
| x = PyInt_FromLong(SIGTRAP); |
| PyDict_SetItemString(d, "SIGTRAP", x); |
| Py_XDECREF(x); |
| #endif |
| #ifdef SIGIOT |
| x = PyInt_FromLong(SIGIOT); |
| PyDict_SetItemString(d, "SIGIOT", x); |
| Py_XDECREF(x); |
| #endif |
| #ifdef SIGABRT |
| x = PyInt_FromLong(SIGABRT); |
| PyDict_SetItemString(d, "SIGABRT", x); |
| Py_XDECREF(x); |
| #endif |
| #ifdef SIGEMT |
| x = PyInt_FromLong(SIGEMT); |
| PyDict_SetItemString(d, "SIGEMT", x); |
| Py_XDECREF(x); |
| #endif |
| #ifdef SIGFPE |
| x = PyInt_FromLong(SIGFPE); |
| PyDict_SetItemString(d, "SIGFPE", x); |
| Py_XDECREF(x); |
| #endif |
| #ifdef SIGKILL |
| x = PyInt_FromLong(SIGKILL); |
| PyDict_SetItemString(d, "SIGKILL", x); |
| Py_XDECREF(x); |
| #endif |
| #ifdef SIGBUS |
| x = PyInt_FromLong(SIGBUS); |
| PyDict_SetItemString(d, "SIGBUS", x); |
| Py_XDECREF(x); |
| #endif |
| #ifdef SIGSEGV |
| x = PyInt_FromLong(SIGSEGV); |
| PyDict_SetItemString(d, "SIGSEGV", x); |
| Py_XDECREF(x); |
| #endif |
| #ifdef SIGSYS |
| x = PyInt_FromLong(SIGSYS); |
| PyDict_SetItemString(d, "SIGSYS", x); |
| Py_XDECREF(x); |
| #endif |
| #ifdef SIGPIPE |
| x = PyInt_FromLong(SIGPIPE); |
| PyDict_SetItemString(d, "SIGPIPE", x); |
| Py_XDECREF(x); |
| #endif |
| #ifdef SIGALRM |
| x = PyInt_FromLong(SIGALRM); |
| PyDict_SetItemString(d, "SIGALRM", x); |
| Py_XDECREF(x); |
| #endif |
| #ifdef SIGTERM |
| x = PyInt_FromLong(SIGTERM); |
| PyDict_SetItemString(d, "SIGTERM", x); |
| Py_XDECREF(x); |
| #endif |
| #ifdef SIGUSR1 |
| x = PyInt_FromLong(SIGUSR1); |
| PyDict_SetItemString(d, "SIGUSR1", x); |
| Py_XDECREF(x); |
| #endif |
| #ifdef SIGUSR2 |
| x = PyInt_FromLong(SIGUSR2); |
| PyDict_SetItemString(d, "SIGUSR2", x); |
| Py_XDECREF(x); |
| #endif |
| #ifdef SIGCLD |
| x = PyInt_FromLong(SIGCLD); |
| PyDict_SetItemString(d, "SIGCLD", x); |
| Py_XDECREF(x); |
| #endif |
| #ifdef SIGCHLD |
| x = PyInt_FromLong(SIGCHLD); |
| PyDict_SetItemString(d, "SIGCHLD", x); |
| Py_XDECREF(x); |
| #endif |
| #ifdef SIGPWR |
| x = PyInt_FromLong(SIGPWR); |
| PyDict_SetItemString(d, "SIGPWR", x); |
| Py_XDECREF(x); |
| #endif |
| #ifdef SIGIO |
| x = PyInt_FromLong(SIGIO); |
| PyDict_SetItemString(d, "SIGIO", x); |
| Py_XDECREF(x); |
| #endif |
| #ifdef SIGURG |
| x = PyInt_FromLong(SIGURG); |
| PyDict_SetItemString(d, "SIGURG", x); |
| Py_XDECREF(x); |
| #endif |
| #ifdef SIGWINCH |
| x = PyInt_FromLong(SIGWINCH); |
| PyDict_SetItemString(d, "SIGWINCH", x); |
| Py_XDECREF(x); |
| #endif |
| #ifdef SIGPOLL |
| x = PyInt_FromLong(SIGPOLL); |
| PyDict_SetItemString(d, "SIGPOLL", x); |
| Py_XDECREF(x); |
| #endif |
| #ifdef SIGSTOP |
| x = PyInt_FromLong(SIGSTOP); |
| PyDict_SetItemString(d, "SIGSTOP", x); |
| Py_XDECREF(x); |
| #endif |
| #ifdef SIGTSTP |
| x = PyInt_FromLong(SIGTSTP); |
| PyDict_SetItemString(d, "SIGTSTP", x); |
| Py_XDECREF(x); |
| #endif |
| #ifdef SIGCONT |
| x = PyInt_FromLong(SIGCONT); |
| PyDict_SetItemString(d, "SIGCONT", x); |
| Py_XDECREF(x); |
| #endif |
| #ifdef SIGTTIN |
| x = PyInt_FromLong(SIGTTIN); |
| PyDict_SetItemString(d, "SIGTTIN", x); |
| Py_XDECREF(x); |
| #endif |
| #ifdef SIGTTOU |
| x = PyInt_FromLong(SIGTTOU); |
| PyDict_SetItemString(d, "SIGTTOU", x); |
| Py_XDECREF(x); |
| #endif |
| #ifdef SIGVTALRM |
| x = PyInt_FromLong(SIGVTALRM); |
| PyDict_SetItemString(d, "SIGVTALRM", x); |
| Py_XDECREF(x); |
| #endif |
| #ifdef SIGPROF |
| x = PyInt_FromLong(SIGPROF); |
| PyDict_SetItemString(d, "SIGPROF", x); |
| Py_XDECREF(x); |
| #endif |
| #ifdef SIGXCPU |
| x = PyInt_FromLong(SIGXCPU); |
| PyDict_SetItemString(d, "SIGXCPU", x); |
| Py_XDECREF(x); |
| #endif |
| #ifdef SIGXFSZ |
| x = PyInt_FromLong(SIGXFSZ); |
| PyDict_SetItemString(d, "SIGXFSZ", x); |
| Py_XDECREF(x); |
| #endif |
| if (!PyErr_Occurred()) |
| return; |
| |
| /* Check for errors */ |
| finally: |
| return; |
| } |
| |
| static void |
| finisignal() |
| { |
| int i; |
| PyObject *func; |
| |
| signal(SIGINT, old_siginthandler); |
| old_siginthandler = SIG_DFL; |
| |
| for (i = 1; i < NSIG; i++) { |
| func = Handlers[i].func; |
| Handlers[i].tripped = 0; |
| Handlers[i].func = NULL; |
| if (i != SIGINT && func != NULL && func != Py_None && |
| func != DefaultHandler && func != IgnoreHandler) |
| signal(i, SIG_DFL); |
| Py_XDECREF(func); |
| } |
| |
| Py_XDECREF(IntHandler); |
| IntHandler = NULL; |
| Py_XDECREF(DefaultHandler); |
| DefaultHandler = NULL; |
| Py_XDECREF(IgnoreHandler); |
| IgnoreHandler = NULL; |
| } |
| |
| |
| |
| /* Declared in pyerrors.h */ |
| int |
| PyErr_CheckSignals() |
| { |
| int i; |
| PyObject *f; |
| |
| if (!is_tripped) |
| return 0; |
| #ifdef WITH_THREAD |
| if (get_thread_ident() != main_thread) |
| return 0; |
| #endif |
| if (!(f = PyEval_GetFrame())) |
| f = Py_None; |
| |
| for (i = 1; i < NSIG; i++) { |
| if (Handlers[i].tripped) { |
| PyObject *result = NULL; |
| PyObject *arglist = Py_BuildValue("(iO)", i, f); |
| Handlers[i].tripped = 0; |
| |
| if (arglist) { |
| result = PyEval_CallObject(Handlers[i].func, |
| arglist); |
| Py_DECREF(arglist); |
| } |
| if (!result) |
| return -1; |
| |
| Py_DECREF(result); |
| } |
| } |
| is_tripped = 0; |
| return 0; |
| } |
| |
| |
| /* Replacements for intrcheck.c functionality |
| * Declared in pyerrors.h |
| */ |
| void |
| PyErr_SetInterrupt() |
| { |
| is_tripped++; |
| Handlers[SIGINT].tripped = 1; |
| Py_AddPendingCall((int (*) Py_PROTO((ANY *)))PyErr_CheckSignals, NULL); |
| } |
| |
| void |
| PyOS_InitInterrupts() |
| { |
| initsignal(); |
| _PyImport_FixupExtension("signal", "signal"); |
| } |
| |
| void |
| PyOS_FiniInterrupts() |
| { |
| finisignal(); |
| } |
| |
| int |
| PyOS_InterruptOccurred() |
| { |
| if (Handlers[SIGINT].tripped) { |
| #ifdef WITH_THREAD |
| if (get_thread_ident() != main_thread) |
| return 0; |
| #endif |
| Handlers[SIGINT].tripped = 0; |
| return 1; |
| } |
| return 0; |
| } |
| |
| void |
| PyOS_AfterFork() |
| { |
| #ifdef WITH_THREAD |
| main_thread = get_thread_ident(); |
| main_pid = getpid(); |
| #endif |
| } |