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Mingw suseconds_t and sigaction fixes.
Added typedef for suseconds_t for systems without this defined. Added signal/sigaction from gnulib because mingw is missing these.
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,44 @@ | ||
| /* Convenience declarations when working with <signal.h>. | ||
| Copyright (C) 2008-2011 Free Software Foundation, Inc. | ||
| 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/>. */ | ||
|
|
||
| #ifndef _GL_SIG_HANDLER_H | ||
| #define _GL_SIG_HANDLER_H | ||
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| #include <signal.h> | ||
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|
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| /* Convenience type when working with signal handlers. */ | ||
| typedef void (*sa_handler_t) (int); | ||
|
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| /* Return the handler of a signal, as a sa_handler_t value regardless | ||
| of its true type. The resulting function can be compared to | ||
| special values like SIG_IGN but it is not portable to call it. */ | ||
| static inline sa_handler_t | ||
| get_handler (struct sigaction const *a) | ||
| { | ||
| #ifdef SA_SIGINFO | ||
| /* POSIX says that special values like SIG_IGN can only occur when | ||
| action.sa_flags does not contain SA_SIGINFO. But in Linux 2.4, | ||
| for example, sa_sigaction and sa_handler are aliases and a signal | ||
| is ignored if sa_sigaction (after casting) equals SIG_IGN. So | ||
| use (and cast) sa_sigaction in that case. */ | ||
| if (a->sa_flags & SA_SIGINFO) | ||
| return (sa_handler_t) a->sa_sigaction; | ||
| #endif | ||
| return a->sa_handler; | ||
| } | ||
|
|
||
| #endif /* _GL_SIG_HANDLER_H */ |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,204 @@ | ||
| /* POSIX compatible signal blocking. | ||
| Copyright (C) 2008-2011 Free Software Foundation, Inc. | ||
| Written by Eric Blake <[email protected]>, 2008. | ||
| 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/>. */ | ||
|
|
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| #include <config.h> | ||
|
|
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| /* Specification. */ | ||
| #include <signal.h> | ||
|
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| #include <errno.h> | ||
| #include <stdint.h> | ||
| #include <stdlib.h> | ||
|
|
||
| /* This implementation of sigaction is tailored to Woe32 behavior: | ||
| signal() has SysV semantics (ie. the handler is uninstalled before | ||
| it is invoked). This is an inherent data race if an asynchronous | ||
| signal is sent twice in a row before we can reinstall our handler, | ||
| but there's nothing we can do about it. Meanwhile, sigprocmask() | ||
| is not present, and while we can use the gnulib replacement to | ||
| provide critical sections, it too suffers from potential data races | ||
| in the face of an ill-timed asynchronous signal. And we compound | ||
| the situation by reading static storage in a signal handler, which | ||
| POSIX warns is not generically async-signal-safe. Oh well. | ||
| Additionally: | ||
| - We don't implement SA_NOCLDSTOP or SA_NOCLDWAIT, because SIGCHLD | ||
| is not defined. | ||
| - We don't implement SA_ONSTACK, because sigaltstack() is not present. | ||
| - We ignore SA_RESTART, because blocking Win32 calls are not interrupted | ||
| anyway when an asynchronous signal occurs, and the MSVCRT runtime | ||
| never sets errno to EINTR. | ||
| - We don't implement SA_SIGINFO because it is impossible to do so | ||
| portably. | ||
| POSIX states that an application should not mix signal() and | ||
| sigaction(). We support the use of signal() within the gnulib | ||
| sigprocmask() substitute, but all other application code linked | ||
| with this module should stick with only sigaction(). */ | ||
|
|
||
| /* Check some of our assumptions. */ | ||
| #if defined SIGCHLD || defined HAVE_SIGALTSTACK || defined HAVE_SIGINTERRUPT | ||
| # error "Revisit the assumptions made in the sigaction module" | ||
| #endif | ||
|
|
||
| /* Out-of-range substitutes make a good fallback for uncatchable | ||
| signals. */ | ||
| #ifndef SIGKILL | ||
| # define SIGKILL (-1) | ||
| #endif | ||
| #ifndef SIGSTOP | ||
| # define SIGSTOP (-1) | ||
| #endif | ||
|
|
||
| /* On native Windows, as of 2008, the signal SIGABRT_COMPAT is an alias | ||
| for the signal SIGABRT. Only one signal handler is stored for both | ||
| SIGABRT and SIGABRT_COMPAT. SIGABRT_COMPAT is not a signal of its own. */ | ||
| #if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__ | ||
| # undef SIGABRT_COMPAT | ||
| # define SIGABRT_COMPAT 6 | ||
| #endif | ||
|
|
||
| /* A signal handler. */ | ||
| typedef void (*handler_t) (int signal); | ||
|
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| /* Set of current actions. If sa_handler for an entry is NULL, then | ||
| that signal is not currently handled by the sigaction handler. */ | ||
| static struct sigaction volatile action_array[NSIG] /* = 0 */; | ||
|
|
||
| /* Signal handler that is installed for signals. */ | ||
| static void | ||
| sigaction_handler (int sig) | ||
| { | ||
| handler_t handler; | ||
| sigset_t mask; | ||
| sigset_t oldmask; | ||
| int saved_errno = errno; | ||
| if (sig < 0 || NSIG <= sig || !action_array[sig].sa_handler) | ||
| { | ||
| /* Unexpected situation; be careful to avoid recursive abort. */ | ||
| if (sig == SIGABRT) | ||
| signal (SIGABRT, SIG_DFL); | ||
| abort (); | ||
| } | ||
|
|
||
| /* Reinstall the signal handler when required; otherwise update the | ||
| bookkeeping so that the user's handler may call sigaction and get | ||
| accurate results. We know the signal isn't currently blocked, or | ||
| we wouldn't be in its handler, therefore we know that we are not | ||
| interrupting a sigaction() call. There is a race where any | ||
| asynchronous instance of the same signal occurring before we | ||
| reinstall the handler will trigger the default handler; oh | ||
| well. */ | ||
| handler = action_array[sig].sa_handler; | ||
| if ((action_array[sig].sa_flags & SA_RESETHAND) == 0) | ||
| signal (sig, sigaction_handler); | ||
| else | ||
| action_array[sig].sa_handler = NULL; | ||
|
|
||
| /* Block appropriate signals. */ | ||
| mask = action_array[sig].sa_mask; | ||
| if ((action_array[sig].sa_flags & SA_NODEFER) == 0) | ||
| sigaddset (&mask, sig); | ||
| sigprocmask (SIG_BLOCK, &mask, &oldmask); | ||
|
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||
| /* Invoke the user's handler, then restore prior mask. */ | ||
| errno = saved_errno; | ||
| handler (sig); | ||
| saved_errno = errno; | ||
| sigprocmask (SIG_SETMASK, &oldmask, NULL); | ||
| errno = saved_errno; | ||
| } | ||
|
|
||
| /* Change and/or query the action that will be taken on delivery of | ||
| signal SIG. If not NULL, ACT describes the new behavior. If not | ||
| NULL, OACT is set to the prior behavior. Return 0 on success, or | ||
| set errno and return -1 on failure. */ | ||
| int | ||
| sigaction (int sig, const struct sigaction *restrict act, | ||
| struct sigaction *restrict oact) | ||
| { | ||
| sigset_t mask; | ||
| sigset_t oldmask; | ||
| int saved_errno; | ||
|
|
||
| if (sig < 0 || NSIG <= sig || sig == SIGKILL || sig == SIGSTOP | ||
| || (act && act->sa_handler == SIG_ERR)) | ||
| { | ||
| errno = EINVAL; | ||
| return -1; | ||
| } | ||
|
|
||
| #ifdef SIGABRT_COMPAT | ||
| if (sig == SIGABRT_COMPAT) | ||
| sig = SIGABRT; | ||
| #endif | ||
|
|
||
| /* POSIX requires sigaction() to be async-signal-safe. In other | ||
| words, if an asynchronous signal can occur while we are anywhere | ||
| inside this function, the user's handler could then call | ||
| sigaction() recursively and expect consistent results. We meet | ||
| this rule by using sigprocmask to block all signals before | ||
| modifying any data structure that could be read from a signal | ||
| handler; this works since we know that the gnulib sigprocmask | ||
| replacement does not try to use sigaction() from its handler. */ | ||
| if (!act && !oact) | ||
| return 0; | ||
| sigfillset (&mask); | ||
| sigprocmask (SIG_BLOCK, &mask, &oldmask); | ||
| if (oact) | ||
| { | ||
| if (action_array[sig].sa_handler) | ||
| *oact = action_array[sig]; | ||
| else | ||
| { | ||
| /* Safe to change the handler at will here, since all | ||
| signals are currently blocked. */ | ||
| oact->sa_handler = signal (sig, SIG_DFL); | ||
| if (oact->sa_handler == SIG_ERR) | ||
| goto failure; | ||
| signal (sig, oact->sa_handler); | ||
| oact->sa_flags = SA_RESETHAND | SA_NODEFER; | ||
| sigemptyset (&oact->sa_mask); | ||
| } | ||
| } | ||
|
|
||
| if (act) | ||
| { | ||
| /* Safe to install the handler before updating action_array, | ||
| since all signals are currently blocked. */ | ||
| if (act->sa_handler == SIG_DFL || act->sa_handler == SIG_IGN) | ||
| { | ||
| if (signal (sig, act->sa_handler) == SIG_ERR) | ||
| goto failure; | ||
| action_array[sig].sa_handler = NULL; | ||
| } | ||
| else | ||
| { | ||
| if (signal (sig, sigaction_handler) == SIG_ERR) | ||
| goto failure; | ||
| action_array[sig] = *act; | ||
| } | ||
| } | ||
| sigprocmask (SIG_SETMASK, &oldmask, NULL); | ||
| return 0; | ||
|
|
||
| failure: | ||
| saved_errno = errno; | ||
| sigprocmask (SIG_SETMASK, &oldmask, NULL); | ||
| errno = saved_errno; | ||
| return -1; | ||
| } |
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