1 /* ABI compatibility for obsolete sigvec function from 4.2BSD.
2 Copyright (C) 1991-2023 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 #include <shlib-compat.h>
20
21 #if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_21)
22
23 # include <signal.h>
24 # include <errno.h>
25 # include <stddef.h>
26
27
28 /* These are the struct sigvec and SV_* bit definitions that
29 used to be in <signal.h>. The whole interface now exists
30 solely for ABI compatibility, so it can just be here. */
31 struct sigvec
32 {
33 __sighandler_t sv_handler; /* Signal handler. */
34 int sv_mask; /* Mask of signals to be blocked. */
35
36 int sv_flags; /* Flags (see below). */
37 };
38 # define SV_ONSTACK (1 << 0)/* Take the signal on the signal stack. */
39 # define SV_INTERRUPT (1 << 1)/* Do not restart system calls. */
40 # define SV_RESETHAND (1 << 2)/* Reset handler to SIG_DFL on receipt. */
41
42
43 /* Include macros to convert between `sigset_t' and old-style mask. */
44 # include <sigset-cvt-mask.h>
45
46 # ifndef SA_RESETHAND
47 /* When sigaction lacks the extension bit for it,
48 we use a wrapper handler to support SV_RESETHAND. */
49 struct sigvec_wrapper_data
50 {
51 __sighandler_t sw_handler;
52 unsigned int sw_mask;
53 };
54
55 static void sigvec_wrapper_handler (int sig) __THROW;
56
57 static struct sigvec_wrapper_data sigvec_wrapper_data[NSIG];
58 # endif
59
60
61 /* If VEC is non-NULL, set the handler for SIG to the `sv_handler' member
62 of VEC. The signals in `sv_mask' will be blocked while the handler runs.
63 If the SV_RESETHAND bit is set in `sv_flags', the handler for SIG will be
64 reset to SIG_DFL before `sv_handler' is entered. If OVEC is non-NULL,
65 it is filled in with the old information for SIG. */
66 int
67 __sigvec (int sig,
68 const struct sigvec *vec,
69 struct sigvec *ovec)
70 {
71 struct sigaction old;
72
73 # ifndef SA_RESETHAND
74 if (vec == NULL || !(vec->sv_flags & SV_RESETHAND))
75 # endif
76 {
77 struct sigaction new, *n;
78
79 if (vec == NULL)
80 n = NULL;
81 else
82 {
83 __sighandler_t handler;
84 unsigned int mask;
85 unsigned int sv_flags;
86 unsigned int sa_flags;
87
88 handler = vec->sv_handler;
89 mask = vec->sv_mask;
90 sv_flags = vec->sv_flags;
91 sa_flags = 0;
92 if (sv_flags & SV_ONSTACK)
93 {
94 # ifdef SA_ONSTACK
95 sa_flags |= SA_ONSTACK;
96 # else
97 __set_errno (ENOSYS);
98 return -1;
99 # endif
100 }
101 # ifdef SA_RESTART
102 if (!(sv_flags & SV_INTERRUPT))
103 sa_flags |= SA_RESTART;
104 # endif
105 # ifdef SA_RESETHAND
106 if (sv_flags & SV_RESETHAND)
107 sa_flags |= SA_RESETHAND;
108 # endif
109 n = &new;
110 new.sa_handler = handler;
111 if (sigset_set_old_mask (&new.sa_mask, mask) < 0)
112 return -1;
113 new.sa_flags = sa_flags;
114 }
115
116 if (__sigaction (sig, n, &old) < 0)
117 return -1;
118 }
119 # ifndef SA_RESETHAND
120 else
121 {
122 __sighandler_t handler;
123 unsigned int mask;
124 struct sigvec_wrapper_data *data;
125 struct sigaction wrapper;
126
127 handler = vec->sv_handler;
128 mask = (unsigned int)vec->sv_mask;
129 data = &sigvec_wrapper_data[sig];
130 wrapper.sa_handler = sigvec_wrapper_handler;
131 /* FIXME: should we set wrapper.sa_mask, wrapper.sa_flags?? */
132 data->sw_handler = handler;
133 data->sw_mask = mask;
134
135 if (__sigaction (sig, &wrapper, &old) < 0)
136 return -1;
137 }
138 # endif
139
140 if (ovec != NULL)
141 {
142 __sighandler_t handler;
143 unsigned int sv_flags;
144 unsigned int sa_flags;
145 unsigned int mask;
146
147 handler = old.sa_handler;
148 sv_flags = 0;
149 sa_flags = old.sa_flags;
150 # ifndef SA_RESETHAND
151 if (handler == sigvec_wrapper_handler)
152 {
153 handler = sigvec_wrapper_data[sig].sw_handler;
154 /* should we use data->sw_mask?? */
155 sv_flags |= SV_RESETHAND;
156 }
157 # else
158 if (sa_flags & SA_RESETHAND)
159 sv_flags |= SV_RESETHAND;
160 # endif
161 mask = sigset_get_old_mask (&old.sa_mask);
162 # ifdef SA_ONSTACK
163 if (sa_flags & SA_ONSTACK)
164 sv_flags |= SV_ONSTACK;
165 # endif
166 # ifdef SA_RESTART
167 if (!(sa_flags & SA_RESTART))
168 # endif
169 sv_flags |= SV_INTERRUPT;
170 ovec->sv_handler = handler;
171 ovec->sv_mask = (int)mask;
172 ovec->sv_flags = (int)sv_flags;
173 }
174
175 return 0;
176 }
177
178 compat_symbol (libc, __sigvec, sigvec, GLIBC_2_0);
179
180 # ifndef SA_RESETHAND
181 static void
182 sigvec_wrapper_handler (int sig)
183 {
184 struct sigvec_wrapper_data *data;
185 struct sigaction act;
186 int save;
187 __sighandler_t handler;
188
189 data = &sigvec_wrapper_data[sig];
190 act.sa_handler = SIG_DFL;
191 act.sa_flags = 0;
192 sigset_set_old_mask (&act.sa_mask, data->sw_mask);
193 handler = data->sw_handler;
194 save = errno;
195 (void) __sigaction (sig, &act, (struct sigaction *) NULL);
196 __set_errno (save);
197
198 (*handler) (sig);
199 }
200 # endif /* No SA_RESETHAND. */
201
202 #endif /* SHLIB_COMPAT */