src/backend/libpq/pqsignal.c

   1 /*-------------------------------------------------------------------------
   2  *
   3  * pqsignal.c
   4  *        Backend signal(2) support (see also src/port/pqsignal.c)
   5  *
   6  * Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
   7  * Portions Copyright (c) 1994, Regents of the University of California
   8  *
   9  *
  10  * IDENTIFICATION
  11  *        src/backend/libpq/pqsignal.c
  12  *
  13  * ------------------------------------------------------------------------
  14  */
  15
  16 #include "postgres.h"
  17
  18 #include "libpq/pqsignal.h"
  19
  20
  21 /* Global variables */
  22 sigset_t        UnBlockSig,
  23                         BlockSig,
  24                         StartupBlockSig;
  25
  26
  27 /*
  28  * Initialize BlockSig, UnBlockSig, and StartupBlockSig.
  29  *
  30  * BlockSig is the set of signals to block when we are trying to block
  31  * signals.  This includes all signals we normally expect to get, but NOT
  32  * signals that should never be turned off.
  33  *
  34  * StartupBlockSig is the set of signals to block during startup packet
  35  * collection; it's essentially BlockSig minus SIGTERM, SIGQUIT, SIGALRM.
  36  *
  37  * UnBlockSig is the set of signals to block when we don't want to block
  38  * signals.
  39  */
  40 void
  41 pqinitmask(void)
  42 {
  43         sigemptyset(&UnBlockSig);
  44
  45         /* Note: InitializeLatchSupport() modifies UnBlockSig. */
  46
  47         /* First set all signals, then clear some. */
  48         sigfillset(&BlockSig);
  49         sigfillset(&StartupBlockSig);
  50
  51         /*
  52          * Unmark those signals that should never be blocked. Some of these signal
  53          * names don't exist on all platforms.  Most do, but might as well ifdef
  54          * them all for consistency...
  55          */
  56 #ifdef SIGTRAP
  57         sigdelset(&BlockSig, SIGTRAP);
  58         sigdelset(&StartupBlockSig, SIGTRAP);
  59 #endif
  60 #ifdef SIGABRT
  61         sigdelset(&BlockSig, SIGABRT);
  62         sigdelset(&StartupBlockSig, SIGABRT);
  63 #endif
  64 #ifdef SIGILL
  65         sigdelset(&BlockSig, SIGILL);
  66         sigdelset(&StartupBlockSig, SIGILL);
  67 #endif
  68 #ifdef SIGFPE
  69         sigdelset(&BlockSig, SIGFPE);
  70         sigdelset(&StartupBlockSig, SIGFPE);
  71 #endif
  72 #ifdef SIGSEGV
  73         sigdelset(&BlockSig, SIGSEGV);
  74         sigdelset(&StartupBlockSig, SIGSEGV);
  75 #endif
  76 #ifdef SIGBUS
  77         sigdelset(&BlockSig, SIGBUS);
  78         sigdelset(&StartupBlockSig, SIGBUS);
  79 #endif
  80 #ifdef SIGSYS
  81         sigdelset(&BlockSig, SIGSYS);
  82         sigdelset(&StartupBlockSig, SIGSYS);
  83 #endif
  84 #ifdef SIGCONT
  85         sigdelset(&BlockSig, SIGCONT);
  86         sigdelset(&StartupBlockSig, SIGCONT);
  87 #endif
  88
  89 /* Signals unique to startup */
  90 #ifdef SIGQUIT
  91         sigdelset(&StartupBlockSig, SIGQUIT);
  92 #endif
  93 #ifdef SIGTERM
  94         sigdelset(&StartupBlockSig, SIGTERM);
  95 #endif
  96 #ifdef SIGALRM
  97         sigdelset(&StartupBlockSig, SIGALRM);
  98 #endif
  99 }