1 /*-------------------------------------------------------------------------
2 *
3 * pqsignal.c
4 * reliable BSD-style signal(2) routine stolen from RWW who stole it
5 * from Stevens...
6 *
7 * Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
8 * Portions Copyright (c) 1994, Regents of the University of California
9 *
10 *
11 * IDENTIFICATION
12 * src/port/pqsignal.c
13 *
14 * We now assume that all Unix-oid systems have POSIX sigaction(2)
15 * with support for restartable signals (SA_RESTART). We used to also
16 * support BSD-style signal(2), but there really shouldn't be anything
17 * out there anymore that doesn't have the POSIX API.
18 *
19 * Windows, of course, is resolutely in a class by itself. In the backend,
20 * we don't use this file at all; src/backend/port/win32/signal.c provides
21 * pqsignal() for the backend environment. Frontend programs can use
22 * this version of pqsignal() if they wish, but beware that this does
23 * not provide restartable signals on Windows.
24 *
25 * ------------------------------------------------------------------------
26 */
27
28 #include "c.h"
29
30 #include <signal.h>
31
32 #if !defined(WIN32) || defined(FRONTEND)
33
34 /*
35 * Set up a signal handler, with SA_RESTART, for signal "signo"
36 *
37 * Returns the previous handler.
38 */
39 pqsigfunc
pqsignal(int signo,pqsigfunc func)40 pqsignal(int signo, pqsigfunc func)
41 {
42 #ifndef WIN32
43 struct sigaction act,
44 oact;
45
46 act.sa_handler = func;
47 sigemptyset(&act.sa_mask);
48 act.sa_flags = SA_RESTART;
49 #ifdef SA_NOCLDSTOP
50 if (signo == SIGCHLD)
51 act.sa_flags |= SA_NOCLDSTOP;
52 #endif
53 if (sigaction(signo, &act, &oact) < 0)
54 return SIG_ERR;
55 return oact.sa_handler;
56 #else /* WIN32 */
57 return signal(signo, func);
58 #endif
59 }
60
61 #endif /* !defined(WIN32) || defined(FRONTEND) */
62