Running daemon through rsh
- by Max
I want to run program as daemon in remote machine in Unix. I have rsh connection and I want the program to be running after disconnection.
Suppose I have two programs: util.cpp and forker.cpp.
util.cpp is some utility, for our purpose let it be just infinite root.
util.cpp
int main() {
while (true) {};
return 0;
}
forker.cpp takes some program and run it in separe process through fork() and execve():
forker.cpp
#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <unistd.h>
int main(int argc, char** argv) {
if (argc != 2) {
printf("./a.out <program_to_fork>\n");
exit(1);
}
pid_t pid;
if ((pid = fork()) < 0) {
perror("fork error.");
exit(1);
} else if (!pid) {
// Child.
if (execve(argv[1], &(argv[1]), NULL) == -1) {
perror("execve error.");
exit(1);
}
} else {
// Parent: do nothing.
}
return 0;
}
If I run:
./forker util
forker is finished very quickly, and bash 'is not paused', and util is running as daemon.
But if I run:
scp forker remote_server://some_path/
scp program remote_server://some_path/
rsh remote_server 'cd /some_path; ./forker program'
then it is all the same (i.e. at the remote_sever forker is finishing quickly, util is running) but my bash in local machine is paused.
It is waiting for util stopping (I checked it. If util.cpp is returning than it is ok.), but I don't understand why?!
There are two questions:
1) Why is it paused when I run it through rsh?
I am sure that I chose some stupid way to run daemon. So
2) How to run some program as daemon in C/C++ in unix-like platforms.
Tnx!
