source: trunk/minix/test/select/test14.c@ 22

/*
 * Test name: test14.c
 *
 * Objetive: The purpose of this test is to make sure that select works
 * with ptys.
 *
 * Adapted from test11.c (pipe test).
 * 
 * Ben Gras
 */
#include <time.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/asynchio.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/select.h>
#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#include <string.h>
#include <signal.h>
#include <libutil.h>
char name[100];
void pipehandler(int sig)
{
}
#define CHILDFD 1
#define PARENTFD 0
void do_child(int pty_fds[]) 
{
        /* reads from pipe and prints out the data */
        char data[2048];
        int retval;      
        fd_set fds_read;
        fd_set fds_exception;   
        struct timeval timeout;
        signal(SIGPIPE, pipehandler);
        signal(SIGUSR1, pipehandler);
        /* first, close the write part, since it is not needed */
        close(pty_fds[PARENTFD]);
        
        while(1) {
                FD_ZERO(&fds_read);
                FD_ZERO(&fds_exception);
                FD_SET(pty_fds[CHILDFD], &fds_read);
                FD_SET(pty_fds[CHILDFD], &fds_exception);
                timeout.tv_sec = 5;
                timeout.tv_usec = 0;
                retval = select(pty_fds[CHILDFD]+2,  &fds_read, NULL, &fds_exception, &timeout);
                if (retval == -1) {
                        perror("select");
                        fprintf(stderr, "child: Error in select\n");
                        continue;
                } else printf("child select: %d\n", retval);
                if (FD_ISSET(pty_fds[CHILDFD], &fds_exception)) {
                        printf("child: exception fd set. quitting.\n");
                        break;
                }
                if (FD_ISSET(pty_fds[CHILDFD], &fds_read)) {
                        printf("child: read fd set. reading.\n");
                        if ((retval = read(pty_fds[CHILDFD], data, sizeof(data))) < 0) {
                                perror("read");
                                fprintf(stderr, "child: couldn't read from pty\n");
                                exit(-1);
                        }
                        if(retval == 0) {
                                fprintf(stderr, "child: eof on pty\n");
                                break;
                        }
                        data[retval] = '\0';
                        printf("pid %d pty reads (%d): %s\n", getpid(), retval, data);
                } else printf("child: no fd set\n");
        }
        
        exit(0);
}
void do_parent(int pty_fds[]) 
{
        char data[1024];
        int retval;
        fd_set fds_write;
        signal(SIGPIPE, pipehandler);
        signal(SIGUSR1, pipehandler);
        /* first, close the read part of pty, since it is not needed */
        close(pty_fds[CHILDFD]);
        /* now enter a loop of read user input, and writing it to the pty */
        while (1) {
                FD_ZERO(&fds_write);
                FD_SET(pty_fds[PARENTFD], &fds_write);
                printf("pid %d Waiting for pty ready to write on %s...\n",
                        getpid(), name);
                retval = select(pty_fds[PARENTFD]+2, NULL, &fds_write, NULL, NULL);
                if (retval == -1) {
                        perror("select");
                        fprintf(stderr, "Parent: Error in select\n");
                        exit(-1);
                }               
                printf("Input data: ");
                if(!gets(data)) {
                        printf("parent: eof; exiting\n");
                        break;
                }
                if (!strcmp(data, "exit"))
                        break;
                if (!FD_ISSET(pty_fds[PARENTFD], &fds_write)) {
                        fprintf(stderr, "parent: write fd not set?! retrying\n");
                        continue;
                }
                retval = write(pty_fds[PARENTFD], data, 1024);
                if (retval == -1) {
                        perror("write");
                        fprintf(stderr, "Error writing on pty\n");
                        exit(-1);
                } else printf("wrote %d\n", retval);
        }
        /* got exit from user */
        close(pty_fds[PARENTFD]);       /* close pty, let child know we're done */
        wait(&retval);
        printf("Child exited with status: %d\n", retval);
        exit(0);
}
int main(int argc, char *argv[])
{
        int ptys[2];
        int retval;
        int pid;        
        if(openpty(&ptys[0], &ptys[1], name, NULL, NULL) < 0) {
                perror("openpty");
                return 1;
        }
        printf("Using %s\n", name);
        pid = fork();
        if (pid == -1) {
                fprintf(stderr, "Error forking\n");
                exit(-1);
        }
        if (pid == 0) /* child proc */
                do_child(ptys);
        else
                do_parent(ptys);
        /* not reached */
        return 0;
}