1/* Preemption of Hurd signals before POSIX.1 semantics take over.
2 Copyright (C) 1996-2024 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library 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 GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19#ifndef _HURD_SIGPREEMPT_H
20
21#define _HURD_SIGPREEMPT_H 1
22#define __need_size_t
23#include <stddef.h>
24#include <errno.h>
25#include <bits/types/error_t.h>
26#include <signal.h> /* For sighandler_t, SIG_ERR. */
27#include <bits/types/sigset_t.h>
28struct hurd_sigstate; /* <hurd/signal.h> */
29struct hurd_signal_detail; /* <hurd/signal.h> */
30
31struct hurd_signal_preemptor
32 {
33 /* These members select which signals this structure will apply to.
34 The rest of the structure is only consulted if these match. */
35 sigset_t signals; /* Signals preempted. */
36 unsigned long int first, last; /* Range of sigcode values preempted. */
37
38 /* This function will be called (with SS->lock held) to decide what to
39 do with the signal described. It may modify the codes of the signal
40 passed. If the return value is SIG_ERR, the next matching preemptor
41 is tried, or the normal handling is done for the signal (which may
42 have been changed by the preemptor function). Otherwise, the signal
43 is processed as if the return value were its handler setting. */
44 __sighandler_t (*preemptor) (struct hurd_signal_preemptor *preemptor,
45 struct hurd_sigstate *ss,
46 int *signo, struct hurd_signal_detail *detail);
47 /* If PREEMPTOR is null, act as if it returned HANDLER. */
48 __sighandler_t handler;
49
50 struct hurd_signal_preemptor *next; /* List structure. */
51 };
52
53/* The caller must initialize all members of *PREEMPTOR except `next'.
54 The preemptor is registered on the global list. */
55void hurd_preempt_signals (struct hurd_signal_preemptor *preemptor);
56
57/* Remove a preemptor registered with hurd_preempt_signals. */
58void hurd_unpreempt_signals (struct hurd_signal_preemptor *preemptor);
59
60
61/* Call *OPERATE and return its value. If a signal in SIGSET with a sigcode
62 in the range [FIRST,LAST] arrives during the call, catch it. If HANDLER
63 is a function, it handles the signal in the normal way (i.e. it should
64 longjmp unless it can restart the insn on return). If it is SIG_ERR,
65 hurd_catch_signal returns the sc_error value from the signal (or
66 EGRATUITOUS if that is zero).
67
68 The preemptor structure is passed to *OPERATE, which may modify its
69 sigcode range or functions at any time during which it is guaranteed no
70 signal in SIGSET will arrive. */
71
72error_t hurd_catch_signal (sigset_t sigset,
73 unsigned long int first, unsigned long int last,
74 error_t (*operate) (struct hurd_signal_preemptor *),
75 __sighandler_t handler);
76
77
78/* Convenience functions using `hurd_catch_signal'. */
79
80
81/* Like `memset', but catch faults in DEST. */
82error_t hurd_safe_memset (void *dest, int byte, size_t nbytes);
83
84/* Like `memcpy', but catch faults in SRC. */
85error_t hurd_safe_copyin (void *dest, const void *src, size_t nbytes);
86
87/* Like `memcpy', but catch faults in DEST. */
88error_t hurd_safe_copyout (void *dest, const void *src, size_t nbytes);
89
90/* Like `memmove', but catch faults in SRC or DEST.
91 If only one region is expected to fault, it is more efficient
92 to use `hurd_safe_copyin' or `hurd_safe_copyout' as appropriate. */
93error_t hurd_safe_memmove (void *dest, const void *src, size_t nbytes);
94
95
96#endif /* hurd/sigpreempt.h */
97

source code of glibc/hurd/hurd/sigpreempt.h