/* Includes */
#include <unistd.h> /* Symbolic Constants */
#include <sys/types.h> /* Primitive System Data Types */
#include <errno.h> /* Errors */
#include <stdio.h> /* Input/Output */
#include <stdlib.h> /* General Utilities */
#include <pthread.h> /* POSIX Threads */
#include <string.h> /* String handling */
#include <signal.h>
#include <sys/mman.h>
#include <semaphore.h> /* Semaphore */
#include <limits.h>
#include <stdint.h>
/* Global Variables */
sem_t* semaphore;
pid_t otherPid;
sigset_t sigSet;
pthread_t tid1;
char file[100];
FILE* fptr;
void childProcess()
{
int value;
//get semaphore value
sem_getvalue(semaphore, &value);
printf("Detailed search file count is %d.\n", value);
fprintf(fptr, "_Detailed search file count is %d._\n", value);
printf("Detailed search is grabbing the file. \n");
fprintf(fptr, "_Detailed search is grabbing the file._ \n");
sem_wait(semaphore);
sem_getvalue(semaphore, &value);
printf("Detailed search file count is %d.\n", value);
fprintf(fptr, "_Detailed search file count is %d._\n", value);
//START CRITICAL REGION
printf("Starting to do a detailed search...\n");
fprintf(fptr,"_Starting to do a detailed search..._\n");
for(int i =0; i < 60; ++i){
printf(".\n");
fprintf(fptr, ".\n");
sleep(1);
}
//END CRITICAL REGION
sem_post(semaphore);
//Exit child process
printf("Exit detailed search\n");
fprintf(fptr, "_Exit detailed search_\n");
_exit(0);
}
void* checkHungChild(void*a)
{
int* status = a;
//check if child process is waiting long
printf("Checking if detailed search is doing O.K.....\n");
fprintf(fptr, "_Checking if detailed search is doing O.K....._\n");
sleep(10);
//check if there is a lock on the semaphore
if(sem_trywait(semaphore) != 0){
printf("detailed search appears to be taking a while...\n");
fprintf(fptr, "_detailed search appears to be taking a while..._\n");
*status = 1;
}
else{
printf("detailed search appears to be running fine...\n");
fprintf(fptr, "_detailed search appears to be running fine..._\n");
*status = 0;
}
return NULL;
}
void parentProcess()
{
//Detect hung Child Process and kill it after a timeout
sleep(2);
//check if child process is running
if(getpgid(otherPid) >= 0){
printf("detailed search is running...\n");
fprintf(fptr,"_detailed search is running..._\n");
}
int value;
sem_getvalue(semaphore, &value);
printf("The fast search has a total of %d files related to your input.\n", value);
fprintf(fptr, "_The fast search has a total of %d files related to your input._\n", value);
//check if there is a lock on the semaphore
if(sem_trywait(semaphore) != 0){
pthread_t tid1;
int status = 0;
printf("Detecting if detailed search's hung or running to long to find your file....\n");
fprintf(fptr, "_Detecting if detailed search's hung or running to long to find your file...._\n");
//check if child process is running a long time
if(pthread_create(&tid1, NULL, checkHungChild, &status))
{
printf("ERROR creating timer thread\n");
fprintf(fptr,"_ERROR creating timer thread_\n");
_exit(1);
}
if(pthread_join(tid1,NULL)){
printf("\n ERROR joining timer thread.\n");
fprintf(fptr,"\n_ERROR joining timer thread._\n");
_exit(1);
}
if(status ==1){
//Kill child process
printf("Stopping detailed search on your computer with ID of %d.\n", value);
fprintf(fptr, "_Stopping detailed search on your computer with ID of %d._\n", value);
kill(otherPid, SIGTERM);
printf("detailed search ended.\n");
fprintf(fptr, "_detailed search ended._\n");
//Prove that the child process is killed
printf("Checking if detailed search has been terminated\n");
fprintf(fptr,"_Checking if detailed search has been terminated_\n");
sleep(5);
kill(otherPid,SIGUSR2);
sleep(1);
printf("Confirmed detailed search is done.\n");
fprintf(fptr,"_Confirmed detailed search is done._\n");
printf("Started a fast search.\n");
fprintf(fptr, "_Started a fast search._\n");
//Try to get semaphore
sem_getvalue(semaphore, &value);
printf("Your fast search finds %d file(s).\n", value);
fprintf(fptr, "_Your fast search finds %d file(s)._\n", value);
if(sem_trywait(semaphore) != 0)
{
if(value == 0)
{
sem_post(semaphore);
printf("Cleaned up and finally got the file.\n");
fprintf(fptr,"_Cleaned up and finally got the file._\n");
sem_getvalue(semaphore, &value);
printf("The fast search got %d file related to your input.\n", value);
fprintf(fptr,"_The fast search got %d file related to your input._\n", value);
}
else{
printf("Finally got the file.\n");
fprintf(fptr,"_Finally got the file._\n");
}
//check if the found file is corrupt
//if so, delete the file
printf("Your file is %s.\n", file);
fprintf(fptr,"_Your file is %s._\n", file);
if(strcmp(file, "file2") == 0){
printf("file is corrupted. Deleting file\n");
fprintf(fptr,"_file is corrupted. Deleting file_\n");
sem_destroy(semaphore);
}
}
printf("Exit fast search.\n");
fprintf(fptr, "_Exit fast search._\n");
_exit(0);
}
}
}
//Utility Methods
void signalHandeler1(int signum){
printf("Caught Signal: %d\n", signum);
fprintf(fptr,"_Caught Signal: %d_\n", signum);
printf(" Exit detailed search Process\n");
fprintf(fptr,"_Exit detailed search Process_\n");
sem_post(semaphore);
_exit(0);
}
void signalHandeler2(int signum){
printf("Singal still alive\n");
fprintf(fptr,"_Singal still alive_\n");
}
int main(int argc, char* argv[])
{
fptr = fopen("deadlockoutput.txt", "w+");
pid_t pid;
//ask for user input and make sure input is not empty
//and its a real file (file1 does not exist)
do{
printf("Please input a real file: ");
scanf(" %s", file);
fprintf(fptr,"_Please input a real file: %s_", file);
}while(file==NULL || strcmp(file, "file1") == 0 );
//create shared semaphore
semaphore = (sem_t*)mmap(0,sizeof(sem_t), PROT_READ|
PROT_WRITE,MAP_SHARED|
MAP_ANONYMOUS, -1, 0);
fprintf(fptr, "## Deadlock Program Log File\n\n");
if(sem_init(semaphore,1,1) != 0){
printf("failed to create semaphore.\n");
fprintf(fptr, "_failed to create semaphore._\n");
exit(EXIT_FAILURE);
}
//use fork()
setvbuf(stdout, NULL,_IOLBF,0); //so redirect works
pid = fork();
if (pid == -1)
{
// Error: If fork() returns -1 then an error happened (for example, number of processes reached the limit).
fprintf(stderr,"Can't fork, error %d\n", errno);
fprintf(fptr,"_Can't fork, error %d_\n", errno);
exit(EXIT_FAILURE);
}
printf("Searching your computer for file!\n");
fprintf(fptr,"_Searching your computer for file!_\n");
// OK: If fork() returns non zero then the parent process is running else child process is running
if (pid == 0)
{
printf("fork() returned 0 to run a fast level search\n");
fprintf(fptr,"_fork() returned 0 to run a fast level search_\n");
// Run Producer Process logic as a Child Process
otherPid = getppid();
childProcess();
}
else
{
printf("fork() returned non zero number to run a detailed search\n");
fprintf(fptr,"_fork() returned non zero number to run a detailed search_\n");
// Run Consumer Process logic as a Parent Process
otherPid = pid;
parentProcess();
}
fclose(fptr);
//Cleanup
sem_destroy(semaphore);
// Return OK
return 0;
}
This program used Semaphore for search a file and avoid the deadlock situation. I need to print out the console output result. However, there is a txt but there are no words inside. Please help. The problem that I followed the step for input and output but there is no result inside of the txt file. This is from the assignment: Print the necessary process data using fprintf to show a log of activities: which processes are running, what resource they are trying to access, whether the resource is available, and whether the process is starved.
