Files
unisa_lab_reti_2013_2014/6.process_and_signal/file_communication.c

154 lines
3.5 KiB
C

#include <unistd.h>
#include <stdio.h>
#include <sys/stat.h>
#include <dirent.h>
#include <fcntl.h>
#include <ctype.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/wait.h>
void sigusr1action (int signal){
fprintf(stdout,"Parent:Ricevuto SIGUSR1\n");
}
void sigusr1caction (int signal){
fprintf(stdout,"Child:Ricevuto SIGUSR1\n");
int fd;
fd = open ("share_file", O_RDWR | O_APPEND);
if (fd < 0){
fprintf(stderr,"Child: Error reading file - Errno%d\n",errno);
kill(getpid(),SIGKILL);
}
char a [100];
char b [100];
char op;
lseek(fd,0,SEEK_SET);
char data[2];
data[1]=0;
char input[100]="";
for (read(fd,data,1);data[0]!='\n';read(fd,data,1)){
strcat(input,data);
}
sscanf(input,"%s%*c%s%*c%c",a,b,&op);
int a_data, b_data,calcolo;
char calcolo_s[100];
a_data= atoi(a);
b_data = atoi(b);
if (op=='+'){
calcolo = a_data + b_data;
}else{
if (op=='-'){
calcolo = a_data - b_data;
}else{
if (op=='*'){
calcolo = a_data * b_data;
}else{
calcolo = a_data / b_data;
}
}
}
sprintf(calcolo_s,"%d",calcolo);
write (fd,calcolo_s,strlen(calcolo_s));
kill(getppid(),SIGUSR1);
}
int main (int index, char** in_data){
if (index < 4 || index > 4) {
fprintf(stderr,"Parametri command line non validi\n");
exit(-1);
}
int duplicate;
duplicate = fork();
if (duplicate < 0)
exit(-1);
if (duplicate == 0){
//child
struct sigaction sigusr1cstructure;
sigusr1cstructure.sa_handler = sigusr1caction;
sigusr1cstructure.sa_flags = 0;
sigaction (SIGUSR1, &sigusr1cstructure, NULL);
pause();
fprintf(stdout,"Child:Process %d terminated\n",getpid());
}else{
// parent
int fd;
fd = open ("share_file", O_CREAT | O_WRONLY | O_EXCL,00700);
if (fd < 0){
fprintf(stderr,"Parent:Share_file already exists\n");
fd = open ("share_file", O_WRONLY | O_TRUNC);
if (fd < 0){
fprintf(stderr,"Parent:Error writing to file - Err no%d\n",errno);
char cmd [100] = "kill -P ";
char pid [10];
sprintf (pid,"%d",getpid());
strcat(cmd,pid);
system(cmd);
}
}
write (fd,*(in_data+1),strlen(*(in_data+1)));
write (fd," ",1);
write (fd,*(in_data+2),strlen(*(in_data+2)));
write (fd," ",1);
write (fd,*(in_data+3),strlen(*(in_data+3)));
write (fd,"\n",1);
close(fd);
struct sigaction sigusr1structure;
sigusr1structure.sa_handler = sigusr1action;
sigusr1structure.sa_flags = 0;
sigaction (SIGUSR1, &sigusr1structure, NULL);
int status;
int pid;
kill (duplicate,SIGUSR1);
for (pid = waitpid(-1,&status,0);pid > 0;pid = waitpid(-1,&status,0)){
fprintf(stdout,"Parent:Child %d terminated\n",pid);
}
fprintf(stdout,"Parent:Process %d terminated\n",getpid());
}
return 0;
}