Line data    Source code

       1              : /*-------------------------------------------------------------------------
       2              :  *
       3              :  * legacy-pqsignal.c
       4              :  *    reliable BSD-style signal(2) routine stolen from RWW who stole it
       5              :  *    from Stevens...
       6              :  *
       7              :  * Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
       8              :  * Portions Copyright (c) 1994, Regents of the University of California
       9              :  *
      10              :  *
      11              :  * IDENTIFICATION
      12              :  *    src/interfaces/libpq/legacy-pqsignal.c
      13              :  *
      14              :  *-------------------------------------------------------------------------
      15              :  */
      16              : #include "postgres_fe.h"
      17              : 
      18              : #include <signal.h>
      19              : 
      20              : 
      21              : /*
      22              :  * This version of pqsignal() exists only because pre-9.3 releases
      23              :  * of libpq exported pqsignal(), and some old client programs still
      24              :  * depend on that.  (Since 9.3, clients are supposed to get it from
      25              :  * libpgport instead.)
      26              :  *
      27              :  * Because it is only intended for backwards compatibility, we freeze it
      28              :  * with the semantics it had in 9.2; in particular, this has different
      29              :  * behavior for SIGALRM than the version in src/port/pqsignal.c.
      30              :  *
      31              :  * libpq itself does not use this, nor does anything else in our code.
      32              :  *
      33              :  * src/include/port.h #define's pqsignal as pqsignal_fe or pqsignal_be,
      34              :  * but here we want to export just plain "pqsignal".  We can't rely on
      35              :  * port.h's extern declaration either.  (The point of those #define's
      36              :  * is to ensure that no in-tree code accidentally calls this version.)
      37              :  */
      38              : #undef pqsignal
      39              : 
      40              : typedef void (*pqsigfunc_legacy) (int postgres_signal_arg);
      41              : extern pqsigfunc_legacy pqsignal(int signo, pqsigfunc_legacy func);
      42              : 
      43              : pqsigfunc_legacy
      44            0 : pqsignal(int signo, pqsigfunc_legacy func)
      45              : {
      46              : #ifndef WIN32
      47              :     struct sigaction act,
      48              :                 oact;
      49              : 
      50            0 :     act.sa_handler = func;
      51            0 :     sigemptyset(&act.sa_mask);
      52            0 :     act.sa_flags = 0;
      53            0 :     if (signo != SIGALRM)
      54            0 :         act.sa_flags |= SA_RESTART;
      55              : #ifdef SA_NOCLDSTOP
      56            0 :     if (signo == SIGCHLD)
      57            0 :         act.sa_flags |= SA_NOCLDSTOP;
      58              : #endif
      59            0 :     if (sigaction(signo, &act, &oact) < 0)
      60            0 :         return SIG_ERR;
      61            0 :     return oact.sa_handler;
      62              : #else                           /* WIN32 */
      63              :     return signal(signo, func);
      64              : #endif
      65              : }