1    	/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
2    	/*                                                                           */
3    	/*                  This file is part of the program and library             */
4    	/*         SCIP --- Solving Constraint Integer Programs                      */
5    	/*                                                                           */
6    	/*  Copyright (c) 2002-2023 Zuse Institute Berlin (ZIB)                      */
7    	/*                                                                           */
8    	/*  Licensed under the Apache License, Version 2.0 (the "License");          */
9    	/*  you may not use this file except in compliance with the License.         */
10   	/*  You may obtain a copy of the License at                                  */
11   	/*                                                                           */
12   	/*      http://www.apache.org/licenses/LICENSE-2.0                           */
13   	/*                                                                           */
14   	/*  Unless required by applicable law or agreed to in writing, software      */
15   	/*  distributed under the License is distributed on an "AS IS" BASIS,        */
16   	/*  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. */
17   	/*  See the License for the specific language governing permissions and      */
18   	/*  limitations under the License.                                           */
19   	/*                                                                           */
20   	/*  You should have received a copy of the Apache-2.0 license                */
21   	/*  along with SCIP; see the file LICENSE. If not visit scipopt.org.         */
22   	/*                                                                           */
23   	/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
24   	
25   	/**@file   interrupt.c
26   	 * @ingroup OTHER_CFILES
27   	 * @brief  methods and datastructures for catching the user CTRL-C interrupt
28   	 * @author Tobias Achterberg
29   	 */
30   	
31   	/*---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8----+----9----+----0----+----1----+----2*/
32   	
33   	#include <assert.h>
34   	#include <sys/types.h>
35   	#include <stdlib.h>
36   	#include <signal.h>
37   	
38   	#include "scip/def.h"
39   	#include "scip/pub_message.h"
40   	#include "blockmemshell/memory.h"
41   	#include "scip/interrupt.h"
42   	
43   	
44   	static volatile
45   	int                      ninterrupts = 0;    /**< static variable counting the number of CTRL-C interrupts */
46   	static volatile
47   	int                      nterms = 0;         /**< static variable counting the number of times that the process received a SIGTERM signal */
48   	
49   	
50   	#ifdef SCIP_NO_SIGACTION
51   	typedef void (*SigHdlr)(int);
52   	
53   	/** CTRL-C interrupt data */
54   	struct SCIP_Interrupt
55   	{
56   	   SigHdlr               oldsighdlr;         /**< old CTRL-C interrupt handler */
57   	   int                   nuses;              /**< number of times, the interrupt is captured */
58   	};
59   	
60   	#else
61   	
62   	/** CTRL-C interrupt data */
63   	struct SCIP_Interrupt
64   	{
65   	   struct sigaction      oldsigaction;       /**< old CTRL-C interrupt handler */
66   	   int                   nuses;              /**< number of times, the interrupt is captured */
67   	};
68   	#endif
69   	
70   	/** interrupt handler for CTRL-C interrupts */
71   	static
72   	void interruptHandler(
73   	   int                   signum              /**< interrupt signal number */
74   	   )
75   	{
76   	   SCIP_UNUSED(signum);
77   	
78   	   ninterrupts++;
79   	   if( ninterrupts >= 5 )
80   	   {
81   	      printf("pressed CTRL-C %d times. forcing termination.\n", ninterrupts);
82   	      exit(1);
83   	   }
84   	   else
85   	   {
86   	      printf("pressed CTRL-C %d times (5 times for forcing termination)\n", ninterrupts);
87   	   }
88   	}
89   	
90   	/** creates a CTRL-C interrupt data */
91   	SCIP_RETCODE SCIPinterruptCreate(
92   	   SCIP_INTERRUPT**      interrupt           /**< pointer to store the CTRL-C interrupt data */
93   	   )
94   	{
95   	   assert(interrupt != NULL);
96   	
97   	   SCIP_ALLOC( BMSallocMemory(interrupt) );
98   	   (*interrupt)->nuses = 0;
99   	
100  	   return SCIP_OKAY;
101  	}
102  	
103  	/** frees a CTRL-C interrupt data */
104  	void SCIPinterruptFree(
105  	   SCIP_INTERRUPT**      interrupt           /**< pointer to the CTRL-C interrupt data */
106  	   )
107  	{
108  	   assert(interrupt != NULL);
109  	
110  	   BMSfreeMemory(interrupt);
111  	}
112  	
113  	/** captures the CTRL-C interrupt to call the SCIP's own interrupt handler */
114  	void SCIPinterruptCapture(
115  	   SCIP_INTERRUPT*       interrupt           /**< CTRL-C interrupt data */
116  	   )
117  	{
118  	   assert(interrupt != NULL);
119  	   assert(interrupt->nuses >= 0);
120  	
121  	   if( interrupt->nuses == 0 )
122  	   {
123  	#ifdef SCIP_NO_SIGACTION
124  	      interrupt->oldsighdlr = signal(SIGINT, interruptHandler);
125  	#else
126  	      struct sigaction newaction;
127  	
128  	      /* initialize new signal action */
129  	      newaction.sa_handler = interruptHandler;
130  	      newaction.sa_flags = 0;
131  	      (void)sigemptyset(&newaction.sa_mask);
132  	
133  	      /* set new signal action, and remember old one */
134  	      (void)sigaction(SIGINT, &newaction, &interrupt->oldsigaction);
135  	#endif
136  	
137  	      ninterrupts = 0;
138  	      nterms = 0;
139  	   }
140  	   interrupt->nuses++;
141  	}
142  	
143  	/** releases the CTRL-C interrupt and restores the old interrupt handler */
144  	void SCIPinterruptRelease(
145  	   SCIP_INTERRUPT*       interrupt           /**< CTRL-C interrupt data */
146  	   )
147  	{
148  	   assert(interrupt != NULL);
149  	   assert(interrupt->nuses >= 1);
150  	
151  	   interrupt->nuses--;
152  	   if( interrupt->nuses == 0 )
153  	   {
154  	#ifdef SCIP_NO_SIGACTION
155  	      (void)signal(SIGINT, interrupt->oldsighdlr);
156  	#else
157  	      (void)sigaction(SIGINT, &interrupt->oldsigaction, NULL);
158  	#endif
159  	   }
160  	}
161  	
162  	/** returns whether the user interrupted by pressing CTRL-C */
163  	SCIP_Bool SCIPinterrupted(
164  	   void
165  	   )
166  	{
167  	   return (ninterrupts > 0);
168  	}
169  	
170  	/** returns whether a process termination signal was received */
171  	SCIP_Bool SCIPterminated(
172  	   void
173  	   )
174  	{
175  	   return (nterms > 0);
176  	}
177  	
178  	/** sends a termination signal to all SCIP processes so that they try to terminate as soon as possible
179  	 *
180  	 *  @note For terminating a specific SCIP process use SCIPinterruptSolve().
181  	 */
182  	void SCIPtryTerminate(
183  	   void
184  	   )
185  	{
186  	   nterms++;
187  	}
188  	
189  	/** resets the number of interrupts to 0 */
190  	void SCIPresetInterrupted(
191  	   void
192  	   )
193  	{
194  	   ninterrupts = 0;
195  	   nterms = 0;
196  	}
197  	
198