StdLib/LibC/Signal/Signal.c

   1 /** @file
   2   Implementation of the signal and raise functions as declared in <signal.h>.
   3
   4   Copyright (c) 2010, Intel Corporation. All rights reserved.<BR>
   5   This program and the accompanying materials are licensed and made available under
   6   the terms and conditions of the BSD License that accompanies this distribution.
   7   The full text of the license may be found at
   8   http://opensource.org/licenses/bsd-license.php.
   9
  10   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  11   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
  12
  13 **/
  14 #include <Uefi.h>
  15 #include <Library/UefiLib.h>
  16
  17 #include  <LibConfig.h>
  18 #include  <errno.h>
  19 #include  <signal.h>
  20 #include  <MainData.h>
  21
  22 /** The signal function associates a "signal handler" with a signal number.
  23
  24     The signal function chooses one of three ways in which receipt of the
  25     signal number, sig, is to be subsequently handled. If the value of func
  26     is SIG_DFL, default handling for that signal will occur. If the value of
  27     func is SIG_IGN, the signal will be ignored.  Otherwise, func shall point
  28     to a function to be called when that signal occurs. An invocation of such a
  29     function because of a signal, or (recursively) of any further functions
  30     called by that invocation (other than functions in the standard library),
  31     is called a signal handler.
  32
  33     At program startup, the equivalent of signal(sig, SIG_IGN); may be executed
  34     for some signals selected in an implementation-defined manner; the
  35     equivalent of signal(sig, SIG_DFL); is executed for all other signals
  36     defined by the implementation.
  37
  38     @return   If the request can be honored, the signal function returns the
  39               value of func for the most recent successful call to signal for
  40               the specified signal sig. Otherwise, a value of SIG_ERR is
  41               returned and a positive value is stored in errno.
  42  */
  43 __sighandler_t *
  44 signal(int sig, __sighandler_t *func)
  45 {
  46   __sighandler_t *OldHandler;
  47
  48   if (sig < 0 || sig >= SIG_LAST) {
  49     errno = EINVAL;
  50     return SIG_ERR;
  51   }
  52   OldHandler = gMD->sigarray[sig];
  53   gMD->sigarray[sig] = func;
  54
  55   return OldHandler;
  56 }
  57
  58 static
  59 void
  60 _defaultSignalHandler( int sig )
  61 {
  62   Print(L"\nCaught signal %d.\n", sig);
  63 }
  64
  65 /** Send a signal.
  66
  67     The raise function carries out the actions described for signal, above,
  68     for the signal sig.
  69
  70     If a signal handler is called, the raise function shall not return until
  71     after the signal handler does.
  72
  73     @return   The raise function returns zero if successful,
  74               nonzero if unsuccessful.
  75 **/
  76 int
  77 raise( int sig)
  78 {
  79   __sighandler_t *Handler;
  80
  81   if (sig < 0 || sig >= SIG_LAST) {
  82     return EINVAL;
  83   }
  84   Handler = gMD->sigarray[sig];
  85
  86   if(Handler == SIG_DFL) {
  87     _defaultSignalHandler( sig );
  88   }
  89   else if( Handler != SIG_IGN) {
  90     Handler( sig );
  91   }
  92   return 0;
  93 }