summaryrefslogtreecommitdiff
path: root/signal/sigvec.c
blob: 1c73fb6318d2fedaa507a588a16e8f6320fbc44f (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
/* ABI compatibility for obsolete sigvec function from 4.2BSD.
   Copyright (C) 1991-2016 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <http://www.gnu.org/licenses/>.  */

#include <shlib-compat.h>

#if SHLIB_COMPAT (libc, GLIBC_2_0, GLIBC_2_21)

# include <signal.h>
# include <errno.h>
# include <stddef.h>


/* These are the struct sigvec and SV_* bit definitions that
   used to be in <signal.h>.  The whole interface now exists
   solely for ABI compatibility, so it can just be here.  */
struct sigvec
  {
    __sighandler_t sv_handler;	/* Signal handler.  */
    int sv_mask;		/* Mask of signals to be blocked.  */

    int sv_flags;		/* Flags (see below).  */
  };
# define SV_ONSTACK	(1 << 0)/* Take the signal on the signal stack.  */
# define SV_INTERRUPT	(1 << 1)/* Do not restart system calls.  */
# define SV_RESETHAND	(1 << 2)/* Reset handler to SIG_DFL on receipt.  */


/* Include macros to convert between `sigset_t' and old-style mask. */
# include <sigset-cvt-mask.h>

# ifndef SA_RESETHAND
/* When sigaction lacks the extension bit for it,
   we use a wrapper handler to support SV_RESETHAND.  */
struct sigvec_wrapper_data
{
  __sighandler_t sw_handler;
  unsigned int sw_mask;
};

static void sigvec_wrapper_handler (int sig) __THROW;

static struct sigvec_wrapper_data sigvec_wrapper_data[NSIG];
# endif


/* If VEC is non-NULL, set the handler for SIG to the `sv_handler' member
   of VEC.  The signals in `sv_mask' will be blocked while the handler runs.
   If the SV_RESETHAND bit is set in `sv_flags', the handler for SIG will be
   reset to SIG_DFL before `sv_handler' is entered.  If OVEC is non-NULL,
   it is filled in with the old information for SIG.  */
int
__sigvec (int sig,
          const struct sigvec *vec,
          struct sigvec *ovec)
{
  struct sigaction old;

# ifndef SA_RESETHAND
  if (vec == NULL || !(vec->sv_flags & SV_RESETHAND))
# endif
    {
      struct sigaction new, *n;

      if (vec == NULL)
	n = NULL;
      else
	{
	  __sighandler_t handler;
	  unsigned int mask;
	  unsigned int sv_flags;
	  unsigned int sa_flags;

	  handler = vec->sv_handler;
	  mask = vec->sv_mask;
	  sv_flags = vec->sv_flags;
	  sa_flags = 0;
	  if (sv_flags & SV_ONSTACK)
	    {
# ifdef SA_ONSTACK
	      sa_flags |= SA_ONSTACK;
# else
	      __set_errno (ENOSYS);
	      return -1;
# endif
	    }
# ifdef SA_RESTART
	  if (!(sv_flags & SV_INTERRUPT))
	    sa_flags |= SA_RESTART;
# endif
# ifdef SA_RESETHAND
	  if (sv_flags & SV_RESETHAND)
	    sa_flags |= SA_RESETHAND;
# endif
	  n = &new;
	  new.sa_handler = handler;
	  if (sigset_set_old_mask (&new.sa_mask, mask) < 0)
	    return -1;
	  new.sa_flags = sa_flags;
	}

      if (__sigaction (sig, n, &old) < 0)
	return -1;
    }
# ifndef SA_RESETHAND
  else
    {
      __sighandler_t handler;
      unsigned int mask;
      struct sigvec_wrapper_data *data;
      struct sigaction wrapper;

      handler = vec->sv_handler;
      mask = (unsigned int)vec->sv_mask;
      data = &sigvec_wrapper_data[sig];
      wrapper.sa_handler = sigvec_wrapper_handler;
      /* FIXME: should we set wrapper.sa_mask, wrapper.sa_flags??  */
      data->sw_handler = handler;
      data->sw_mask = mask;

      if (__sigaction (sig, &wrapper, &old) < 0)
	return -1;
    }
# endif

  if (ovec != NULL)
    {
      __sighandler_t handler;
      unsigned int sv_flags;
      unsigned int sa_flags;
      unsigned int mask;

      handler = old.sa_handler;
      sv_flags = 0;
      sa_flags = old.sa_flags;
# ifndef SA_RESETHAND
      if (handler == sigvec_wrapper_handler)
	{
	  handler = sigvec_wrapper_data[sig].sw_handler;
	  /* should we use data->sw_mask?? */
	  sv_flags |= SV_RESETHAND;
	}
# else
     if (sa_flags & SA_RESETHAND)
	sv_flags |= SV_RESETHAND;
# endif
      mask = sigset_get_old_mask (&old.sa_mask);
# ifdef SA_ONSTACK
     if (sa_flags & SA_ONSTACK)
	sv_flags |= SV_ONSTACK;
# endif
# ifdef SA_RESTART
     if (!(sa_flags & SA_RESTART))
# endif
	sv_flags |= SV_INTERRUPT;
      ovec->sv_handler = handler;
      ovec->sv_mask = (int)mask;
      ovec->sv_flags = (int)sv_flags;
    }

  return 0;
}

compat_symbol (libc, __sigvec, sigvec, GLIBC_2_0);

# ifndef SA_RESETHAND
static void
sigvec_wrapper_handler (int sig)
{
  struct sigvec_wrapper_data *data;
  struct sigaction act;
  int save;
  __sighandler_t handler;

  data = &sigvec_wrapper_data[sig];
  act.sa_handler = SIG_DFL;
  act.sa_flags = 0;
  sigset_set_old_mask (&act.sa_mask, data->sw_mask);
  handler = data->sw_handler;
  save = errno;
  (void) __sigaction (sig, &act, (struct sigaction *) NULL);
  __set_errno (save);

  (*handler) (sig);
}
# endif  /* No SA_RESETHAND.  */

#endif  /* SHLIB_COMPAT */