AutonomousSequence::AutonomousSequence(){
startPosition = leftBack;
puts("constructed without parameter");
DoSequence();
}
void DoSubshell(command_t command, int pipe_write, int pipe_read)
{
mode_t fd_mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH; // user: r/w, group: r, other: r
pid_t pid;
int status; // Return status of execute command
int new_fd_input; // input file descriptor
int new_fd_output; // output file descriptor
int fd_output = -1;
int fd_input = -1;
int is_fd_output = 0; // flag of fd_output
int is_fd_input = 0; // flag of fd_input
//printf("In Subshell\n");
//printf("Type: %d\n", command->type);
pid = fork();
if (pid == 0)
{
//printf("IN CHILD\n");
if (command->input != NULL) // I/O redirection has higher priority than pipe
{
fd_input = open(command->input, O_RDONLY, fd_mode);
is_fd_input = 1; // flag of fd_input
if (fd_input < 0)
{
switch (errno)
{
case ENOENT:
case ENOTDIR:
case EACCES:
error(1, 0, "%s", strerror(errno));
exit(-1);
break;
default:
error(1, 0, "some error happened in chdir");
exit(-1);
}
}
new_fd_input = dup2(fd_input, STDIN_FILENO); //STDIN_FILENO = 0;
if (new_fd_input != 0)
{
exit(-1);
}
close(fd_input);
}
else // No Input redirection, then check pipe input
{
if (pipe_read != -1)
{
new_fd_input = dup2(pipe_read, STDIN_FILENO); //STDIN_FILENO = 0;
if (new_fd_input != 0)
{
exit(-1);
}
close(pipe_read);
}
}
if (command->output != NULL) // I/O redirection has higher priority than pipe
{
fd_output = open(command->output, O_WRONLY|O_CREAT|O_TRUNC, fd_mode); // r/w, create if not exist, trunc to zero before write
is_fd_output = 1; // flag of fd_output
if (fd_output < 0)
{
switch (errno)
{
case ENOENT:
case ENOTDIR:
case EACCES:
error(1, 0, "%s", strerror(errno));
exit(-1);
break;
default:
error(1, 0, "some error happened in chdir");
exit(-1);
}
}
new_fd_output = dup2(fd_output, STDOUT_FILENO);
if (new_fd_output != 1)
{
exit(-1);
}
close(fd_output);
}
else // No output redirection, then check pipe output
{
if (pipe_write != -1)
{
new_fd_output = dup2(pipe_write, STDOUT_FILENO);
if (new_fd_output != 1)
{
exit(-1);
}
close(pipe_write);
}
}
DoSequence(command->u.subshell_command);
exit(0);
}
else if (pid > 0)
{
//printf("IN FATHER\n");
if (pipe_read != -1)
close(pipe_read); // Very important, must close the pipe fd!
if (pipe_write != -1)
close(pipe_write);
if (is_fd_input)
close(fd_input);
if (is_fd_output)
close(fd_output);
wait(&status);
command->status = status;
//printf("OUT FATHER\n");
}
else
{
error(1, 0, "%s", strerror(errno));
}
}
AutonomousSequence::AutonomousSequence(StartPosition startPosition){
this->startPosition = startPosition;
puts("constructed auto with config");
DoSequence();
}
