I am wondering how I can pass a file descriptor through the execve()
command and then access it on the other side. I know that I can use dup2
to redirect the file-descriptor but I cannot do that. I am required to actually pass the file descriptor to the child and use it in the child.
What I have done so far:
Parent makes pipe
+ args like the following:
int pfd[2];
if(pipe(pfd) == -1)
exitWithError("PIPE FAILED", 1);
char *args_1[] = {"reader", argv[1], (char*) pfd, (char *) 0};
Then the child calls execve
after fork()
like the following:
close(pfd[1]);
execve("./reader", args_1, NULL);
Then, in the reader program I try to access pipe descriptor that was passed:
int main(int argc, char* argv[]){
...
write(argv[2][1], buf, read_test);
argv[2]
should be referencing the pipe descriptor, then the argv[1]
should go to the write end of the pipe. I am almost positive that I need to do some type-casting differently here, but everything I try doesn't quite work out.
NOTE: I have a working version of this program using dup2
to redirect to stdin
and stdout
for the children, but I have to actually pass the pipe descriptor to a child as per instructions of the project.
Any help is appreciated.