TB10.1 Example Applications: examples/PIPS/posixsignals/sigtermSignal/src/sigtermSignal.c Source File

00001 // sigtermSignal.c
+00002 //
+00003 // Copyright (c) 2010 Nokia Corporation and/or its subsidiary(-ies).
+00004 // All rights reserved.
+00005 // This component and the accompanying materials are made available
+00006 // under the terms of "Eclipse Public License v1.0"
+00007 // which accompanies this distribution, and is available
+00008 // at the URL "http://www.eclipse.org/legal/epl-v10.html".
+00009 //
+00010 // Initial Contributors:
+00011 // Nokia Corporation - initial contribution.
+00012 //
+00013 // Contributors:
+00014 //
+00015 // Description: The source code file for sigtermSignal.
+00016 //
+00017 
+00018 #include <stdio.h>
+00019 #include <stdlib.h>
+00020 #include <unistd.h>
+00021 #include <sys/types.h>
+00022 #include <signal.h>
+00023 #include <e32def.h>
+00024 #include <time.h>
+00025 
+00026 
+00027 FILE *gfp = NULL;
+00028 char *testfile = "C:\\testfile.txt";
+00029 
+00033 void PressKey()
+00034     {
+00035     int ch;
+00036     printf("Press 'e'+Enter to exit\n");
+00037     while((ch=getchar())!= 'e')
+00038         {
+00039         if(ch == '\n')
+00040             continue;
+00041         else
+00042             printf("wrong option selected, please try again!!!\n");
+00043         }
+00044     }
+00051 void SIGTERM_handler(int signum)
+00052     {
+00053     if(signum == SIGTERM)
+00054         {
+00055         if(gfp != NULL)
+00056             {
+00057             printf("Received the SIGTERM signal from the raiseSignal process\n");
+00058             fclose(gfp);
+00059             remove(testfile);
+00060             gfp = NULL;
+00061             printf("The open file descriptor was closed\n");
+00062             PressKey();
+00063             exit (0);
+00064             }
+00065         }
+00066     }
+00067 
+00077 int main()
+00078     {
+00079     char input[11];   
+00080     int count = 0,num;
+00081     int ch,ret;
+00082     pid_t usrProcsID;
+00083     const int delay = 4;                                    //Time delay of 4 sec provided.
+00084     const int size = 50;                                    //No.of characters allowed in the filename.
+00085     const int index = 3;                                    //No.of elements in the array.
+00086     
+00087     char *usrProcess = "Z:\\sys\\bin\\raisesignal.exe";    //Filename of process used for raising SIGTERM signal.
+00088     char **argv = (char**)malloc(index*sizeof(char*));      //Variable holding values to be passed on to the raiseSignal process. 
+00089     argv[0] = (char*)malloc(size*sizeof(char));
+00090     argv[1] = (char*)malloc(index*sizeof(char));
+00091     argv[2] = NULL;
+00092 
+00093     
+00094     strcpy(argv[0], "z:\\sys\\bin\\raisesignal.exe");       //argv[0] holding name of the child process.
+00095     sprintf(argv[1],"%d",getpid());                         //argv[1] holding parent pid.
+00096 
+00097     printf("*****************************************************************************************\n");
+00098     printf("* Welcome to the demonstration of a graceful process termination using a SIGTERM signal *\n");
+00099     printf("*****************************************************************************************\n");
+00100     
+00101     printf("* This example shows how a SIGTERM signal can be used to gracefully terminate a process.\n");
+00102     printf("* The example first creates a process called sigtermSignal, assigns a custom handler\nfor the SIGTERM signal, opens a file and gets names from the user to be written in to it.\n");
+00103     printf("* It then simultaneously spawns a raiseSignal process and starts reading from the file.\n");
+00104     printf("* The raiseSignal process sends a SIGTERM signal to the sigtermSignal process.\n");
+00105     printf("* On receiving the SIGTERM signal, the sigtermSignal process closes all the \nopen file descriptors and prepares to exit.\n");
+00106     
+00107     printf("\nPress the Enter key to continue\n");
+00108     getchar();
+00109 
+00110     signal(SIGTERM, SIGTERM_handler);
+00111     printf("************ In the sigtermSignal process ************\n");
+00112     printf("Enter the number of names you want to enter (e.g. 8) :\n");
+00113     scanf("%d", &count);
+00114     gfp=fopen(testfile, "w+");   //Opening the file for read and write.
+00115     if(gfp != NULL)
+00116         {
+00117         printf("File open sucessful\n");
+00118         }
+00119     else
+00120         {
+00121         printf("File open failed\n");
+00122         }
+00123     for(num=1; num<=count; num++)
+00124         {
+00125         printf("Name (%d)=", num);
+00126         scanf("%s", input);
+00127         fprintf(gfp, "%s\n", input);
+00128         }
+00129     
+00130     printf("Press the Enter key to spawn the raiseSignal process\n");
+00131     getchar();
+00132     getchar();
+00133     //Spawning raiseSignal process to accept user input.
+00134     ret = posix_spawn(&usrProcsID,usrProcess,NULL,NULL,argv,(char**)NULL);
+00135     if(ret != 0)     
+00136         {         
+00137         printf("\n*** failure posix_spawn ***\n");        
+00138         return EXIT_FAILURE;     
+00139         }
+00140      rewind(gfp);
+00141      printf("Starting to read from the file\n");
+00142      for(num=1; num<=count; num++)
+00143          {
+00144          sleep (delay);       
+00145          printf("Name (%d)=", num);
+00146          while((ch=(fgetc(gfp))) != '\n')
+00147                   {
+00148                   putchar(ch);
+00149                   }
+00150          printf("\n");
+00151          
+00152          }
+00153     if(!fclose(gfp))
+00154         {
+00155         remove(testfile);
+00156         gfp = NULL;
+00157         printf("File closed successfully\n");
+00158         }
+00159     else
+00160         {
+00161         printf("File close failed\n");
+00162         }
+00163   
+00164     PressKey();
+00165     return EXIT_SUCCESS;
+00166     }
+