Redirecting STDOUT to STDIN of a child process
Hello, I'm trying to implement a basic shell in c, and so far i have the basic functions and command line input working great, and the & works find, however I'm trying to get pipes to work, my problem is that I'm getting a SIGPIPE when using the pipes
here is a code snip it:
Code:
/* Fork the process to allow program being executed a new PID and
* Protect the integrity of the shell process.
*/
pid = fork();
pipe(data_pipe);
switch (pid)
{
case -1: /* fork failed. */
perror("fork");
return 0;
case 0: /* inside child process. */
close(STDIN_FILENO);
dup2(data_pipe[1],STDIN_FILENO);
close(data_pipe[0]);
//close(data_pipe[1]); // may or may not need to do this...
/* creat a new command struct so we dont over write parent
* processes shared memory
*/
struct command_t command2;
int lcv = 0;
/* Initalize the command structure and allocate into memory */
command2.name = (char*)malloc(MAX_ARG_LEN);
command2.argc = 0;
command2.opv = (char*)malloc(MAX_ARG_LEN);
for(lcv=0; lcv<MAX_ARGS;lcv++)
{ command2.argv[lcv] = (char*)malloc(MAX_ARG_LEN);
}
strcat(command->opv,"\n"); // hack job to make parsing work
exeCommand(pathv,&command2,&command->opv);
default: /* inside parent process. */
close(STDOUT_FILENO);
dup2(data_pipe[1],STDOUT_FILENO);
close(data_pipe[0]);
//close(data_pipe[1]); // may or may not be needed.
execvp(command->name,command->argv);
}
I've been working on this for days because from what i can tell it should be working fine... but I'm kinda new to some of these things so I'm sure I'm missing it. heck i might be doing this entirely wrong for all i know :), i didn't want to post here cuz well i wanted to figure it out on my own but after a couple of days i'm starting get sleepy. if all the coded is needed i can post that too...
any help anyone can offer would be much appreciated.
