minix/test/select/test14.c

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/*
* 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>
void pipehandler(int sig)
{
}
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[1]);
while(1) {
FD_ZERO(&fds_read);
FD_ZERO(&fds_exception);
FD_SET(pty_fds[0], &fds_read);
FD_SET(pty_fds[0], &fds_exception);
timeout.tv_sec = 5;
timeout.tv_usec = 0;
retval = select(pty_fds[0]+1, &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[0], &fds_exception)) {
printf("child: exception fd set. quitting.\n");
break;
}
if (FD_ISSET(pty_fds[0], &fds_read)) {
printf("child: read fd set. reading.\n");
if ((retval = read(pty_fds[0], data, sizeof(data))) < 0) {
perror("read");
fprintf(stderr, "child: couldn't read from pipe\n");
exit(-1);
}
if(retval == 0) {
fprintf(stderr, "child: eof on pipe\n");
break;
}
data[retval] = '\0';
printf("pid %d eipe 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[0]);
/* now enter a loop of read user input, and writing it to the pty */
while (1) {
FD_ZERO(&fds_write);
FD_SET(pty_fds[1], &fds_write);
printf("pid %d Waiting for pty ready to write...\n", getpid());
retval = select(pty_fds[1]+1, 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[1], &fds_write)) {
fprintf(stderr, "parent: write fd not set?! retrying\n");
continue;
}
retval = write(pty_fds[1], &data, 1024);
if (retval == -1) {
perror("write");
fprintf(stderr, "Error writing on pty\n");
exit(-1);
}
}
/* got exit from user */
close(pty_fds[1]); /* 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 pipes[2];
int retval;
int pid;
if(openpty(&pipes[0], &pipes[1], NULL, NULL, NULL) < 0) {
perror("openpty");
return 1;
}
sleep(50);
pid = fork();
if (pid == -1) {
fprintf(stderr, "Error forking\n");
exit(-1);
}
if (pid == 0) /* child proc */
do_child(pipes);
else
do_parent(pipes);
/* not reached */
return 0;
}