1 | /* Implementation of sigwait function from POSIX.1c. |
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2 | Copyright (C) 1996, 1997, 1999, 2000 Free Software Foundation, Inc. |
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3 | This file is part of the GNU C Library. |
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4 | Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996. |
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5 | |
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6 | The GNU C Library is free software; you can redistribute it and/or |
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7 | modify it under the terms of the GNU Lesser General Public |
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8 | License as published by the Free Software Foundation; either |
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9 | version 2.1 of the License, or (at your option) any later version. |
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10 | |
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11 | The GNU C Library is distributed in the hope that it will be useful, |
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12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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14 | Lesser General Public License for more details. |
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15 | |
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16 | You should have received a copy of the GNU Lesser General Public |
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17 | License along with the GNU C Library; if not, write to the Free |
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18 | Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
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19 | 02111-1307 USA. */ |
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20 | |
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21 | #include <errno.h> |
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22 | #include <signal.h> |
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23 | #include <stddef.h> /* For NULL. */ |
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24 | |
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25 | #include <machine/weakalias.h> |
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26 | |
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27 | /* This is our dummy signal handler we use here. */ |
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28 | static void ignore_signal (int sig); |
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29 | |
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30 | /* Place where to remember which signal we got. Please note that this |
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31 | implementation cannot be used for the threaded libc. The |
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32 | libpthread must provide an own version. */ |
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33 | static int was_sig; |
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34 | |
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35 | |
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36 | int |
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37 | __sigwait (const sigset_t *set, int *sig) |
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38 | { |
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39 | sigset_t tmp_mask; |
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40 | struct sigaction saved[NSIG]; |
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41 | struct sigaction action; |
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42 | int save_errno; |
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43 | int this; |
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44 | |
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45 | /* Prepare set. */ |
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46 | sigfillset (&tmp_mask); |
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47 | |
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48 | /* Unblock all signals in the SET and register our nice handler. */ |
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49 | action.sa_handler = ignore_signal; |
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50 | action.sa_flags = 0; |
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51 | sigfillset (&action.sa_mask); /* Block all signals for handler. */ |
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52 | |
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53 | /* Make sure we recognize error conditions by setting WAS_SIG to a |
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54 | value which does not describe a legal signal number. */ |
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55 | was_sig = -1; |
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56 | |
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57 | for (this = 1; this < NSIG; ++this) |
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58 | if (sigismember (set, this)) |
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59 | { |
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60 | /* Unblock this signal. */ |
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61 | sigdelset (&tmp_mask, this); |
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62 | |
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63 | /* Register temporary action handler. */ |
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64 | if (__sigaction (this, &action, &saved[this]) != 0) |
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65 | goto restore_handler; |
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66 | } |
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67 | |
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68 | /* Now we can wait for signals. */ |
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69 | __sigsuspend (&tmp_mask); |
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70 | |
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71 | restore_handler: |
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72 | save_errno = errno; |
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73 | |
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74 | while (--this >= 1) |
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75 | if (sigismember (set, this)) |
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76 | /* We ignore errors here since we must restore all handlers. */ |
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77 | __sigaction (this, &saved[this], NULL); |
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78 | |
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79 | errno = (save_errno); |
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80 | |
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81 | /* Store the result and return. */ |
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82 | *sig = was_sig; |
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83 | return was_sig == -1 ? -1 : 0; |
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84 | } |
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85 | weak_alias (__sigwait, sigwait) |
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86 | |
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87 | |
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88 | static void |
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89 | ignore_signal (int sig) |
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90 | { |
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91 | /* Remember the signal. */ |
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92 | was_sig = sig; |
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93 | } |
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