Mercurial > gnulib
annotate lib/fatal-signal.h @ 40237:b1386ce84ff5
fatal-signal: Add function that lists the fatal signals.
* lib/fatal-signal.h (get_fatal_signals): New declaration.
* lib/fatal-signal.c (get_fatal_signals): New function.
| author | Bruno Haible <bruno@clisp.org> |
|---|---|
| date | Sat, 16 Mar 2019 17:48:06 +0100 |
| parents | b06060465f09 |
| children | 3ac749aa0041 |
| rev | line source |
|---|---|
| 4770 | 1 /* Emergency actions in case of a fatal signal. |
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maint: Run 'make update-copyright'
Paul Eggert <eggert@cs.ucla.edu>
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2 Copyright (C) 2003-2004, 2009-2019 Free Software Foundation, Inc. |
| 4770 | 3 Written by Bruno Haible <bruno@clisp.org>, 2003. |
| 4 | |
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Change copyright notice from GPLv2+ to GPLv3+.
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5 This program is free software: you can redistribute it and/or modify |
| 4770 | 6 it under the terms of the GNU General Public License as published by |
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7 the Free Software Foundation; either version 3 of the License, or |
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8 (at your option) any later version. |
| 4770 | 9 |
| 10 This program is distributed in the hope that it will be useful, | |
| 11 but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
| 13 GNU General Public License for more details. | |
| 14 | |
| 15 You should have received a copy of the GNU General Public License | |
| 19190 | 16 along with this program. If not, see <https://www.gnu.org/licenses/>. */ |
| 4770 | 17 |
| 18 | |
| 19 #ifdef __cplusplus | |
| 20 extern "C" { | |
| 21 #endif | |
| 22 | |
| 23 | |
| 24 /* It is often useful to do some cleanup action when a usually fatal signal | |
| 25 terminates the process, like removing a temporary file or killing a | |
| 26 subprocess that may be stuck waiting for a device, pipe or network input. | |
| 27 Such signals are SIGHUP, SIGINT, SIGPIPE, SIGTERM, and possibly others. | |
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Signals whose handler is set to SIG_IGN are not fatal.
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28 The limitation of this facility is that it cannot work for SIGKILL. |
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29 |
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30 Signals with a SIG_IGN handler are considered to be non-fatal. The |
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31 functions in this file assume that when a SIG_IGN handler is installed |
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32 for a signal, it was installed before any functions in this file were |
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33 called and it stays so for the whole lifetime of the process. */ |
| 4770 | 34 |
| 35 /* Register a cleanup function to be executed when a catchable fatal signal | |
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36 occurs. |
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37 |
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38 Restrictions for the cleanup function: |
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39 - The cleanup function can do all kinds of system calls. |
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40 - It can also access application dependent memory locations and data |
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41 structures provided they are in a consistent state. One way to ensure |
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42 this is through block_fatal_signals()/unblock_fatal_signals(), see |
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43 below. Another - more tricky - way to ensure this is the careful use |
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44 of 'volatile'. |
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45 However, |
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46 - malloc() and similarly complex facilities are not safe to be called |
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47 because they are not guaranteed to be in a consistent state. |
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48 - Also, the cleanup function must not block the catchable fatal signals |
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49 and leave them blocked upon return. |
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50 |
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51 The cleanup function is executed asynchronously. It is unspecified |
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52 whether during its execution the catchable fatal signals are blocked |
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53 or not. */ |
| 4770 | 54 extern void at_fatal_signal (void (*function) (void)); |
| 55 | |
| 56 | |
| 57 /* Sometimes it is necessary to block the usually fatal signals while the | |
| 58 data structures being accessed by the cleanup action are being built or | |
| 59 reorganized. This is the case, for example, when a temporary file or | |
| 60 directory is created through mkstemp() or mkdtemp(), because these | |
| 61 functions create the temporary file or directory _before_ returning its | |
| 62 name to the application. */ | |
| 63 | |
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64 /* Temporarily delay the catchable fatal signals. |
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65 The signals will be blocked (= delayed) until the next call to |
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66 unblock_fatal_signals(). If the signals are already blocked, a further |
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67 call to block_fatal_signals() has no effect. */ |
| 4770 | 68 extern void block_fatal_signals (void); |
| 69 | |
| 70 /* Stop delaying the catchable fatal signals. */ | |
| 71 extern void unblock_fatal_signals (void); | |
| 72 | |
| 73 | |
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74 /* Return the list of signals that block_fatal_signals/unblock_fatal_signals |
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75 would block or unblock. |
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76 Fills signals[0..count-1] and returns count. */ |
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77 extern unsigned int get_fatal_signals (int signals[64]); |
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78 |
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79 |
| 4770 | 80 #ifdef __cplusplus |
| 81 } | |
| 82 #endif |