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author | Jeroen Demeyer <J.Demeyer@UGent.be> | 2019-05-10 01:28:57 (GMT) |
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committer | Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com> | 2019-05-10 01:28:56 (GMT) |
commit | d237b3f0f61990c972b84c45eb4fe137db51a6a7 (patch) | |
tree | 68f1220b79ca14dcfa10b648b9f2b0ba446bce4e /Modules | |
parent | d267ac20c309e37d85a986b4417aa8ab4d05dabc (diff) | |
download | cpython-d237b3f0f61990c972b84c45eb4fe137db51a6a7.zip cpython-d237b3f0f61990c972b84c45eb4fe137db51a6a7.tar.gz cpython-d237b3f0f61990c972b84c45eb4fe137db51a6a7.tar.bz2 |
bpo-36601: clarify signal handler comment and remove unnecessary pid check. (GH-12784)
https://bugs.python.org/issue36601
Diffstat (limited to 'Modules')
-rw-r--r-- | Modules/signalmodule.c | 25 |
1 files changed, 10 insertions, 15 deletions
diff --git a/Modules/signalmodule.c b/Modules/signalmodule.c index 8c5a0d0..43a4da1 100644 --- a/Modules/signalmodule.c +++ b/Modules/signalmodule.c @@ -73,11 +73,12 @@ class sigset_t_converter(CConverter): /* NOTES ON THE INTERACTION BETWEEN SIGNALS AND THREADS - When threads are supported, we want the following semantics: + We want the following semantics: - only the main thread can set a signal handler + - only the main thread runs the signal handler + - signals can be delivered to any thread - 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 @@ -88,17 +89,17 @@ class sigset_t_converter(CConverter): 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. + delivered to one random thread. On Linux, signals are delivered to + the main thread (unless the main thread is blocking the signal, for + example because it's already handling the same signal). Since we + allow signals to be delivered to any thread, this works fine. The + only oddity is that the thread executing the Python signal handler + may not be the thread that received the signal. */ #include <sys/types.h> /* For pid_t */ #include "pythread.h" static unsigned long main_thread; -static pid_t main_pid; static PyInterpreterState *main_interp; static volatile struct { @@ -326,11 +327,7 @@ signal_handler(int sig_num) { int save_errno = errno; - /* See NOTES section above */ - if (getpid() == main_pid) - { - trip_signal(sig_num); - } + trip_signal(sig_num); #ifndef HAVE_SIGACTION #ifdef SIGCHLD @@ -1328,7 +1325,6 @@ PyInit__signal(void) int i; main_thread = PyThread_get_thread_ident(); - main_pid = getpid(); main_interp = _PyInterpreterState_Get(); /* Create the module and add the functions */ @@ -1739,7 +1735,6 @@ _PySignal_AfterFork(void) * the interpreter had an opportunity to call the handlers. issue9535. */ _clear_pending_signals(); main_thread = PyThread_get_thread_ident(); - main_pid = getpid(); main_interp = _PyInterpreterState_Get(); } |