[linh]

/* THE CODE BELOW CAUSES A RUN TIME ERROR */
system ("ifconfig eth1 \"$ETH1\" netmask 255.255.255.0");

==================================
root:~# ./test-small-network-sh-2
aaaaa
No address associated with name
ifconfig: `--help' gives usage information.
==================================

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

/*******************************************/

int main()
{
FILE *f, *panic_file, *fopen();
FILE *file_pointer;

file_pointer = popen("ifconfig eth0 up", "r");
file_pointer = popen("echo -e \"aaaaa\"", "w");

f = popen ("ETH0=DHCP", "r");
f = popen ("ETH1=10.0.1.1", "r");
f = popen ("NETMASK=", "r");
f = popen ("BROADCAST=", "r");
f = popen ("GATEWAY=127.0.0.1", "r");

f = popen ("source /etc/yellowbox/network-config", "r");

panic_file = fopen ("/proc/sys/kernel/panic", "w");
putc ('5', panic_file);

f = popen ("ifconfig lo 127.0.0.1", "r");
f = popen ("ifconfig eth0 up", "r");

/* THE CODE BELOW CAUSES A RUN TIME ERROR */
system ("ifconfig eth1 \"$ETH1\" netmask 255.255.255.0");

pclose (f);
pclose (file_pointer);
fclose (panic_file);
}

[dwise1_aol]

Looks like it's the old shell game again.

When you open a new shell and create shell variables, those variables only exist within that shell's environment. When you close the shell, they go away. It's somewhat like creating local variables within a C function; they only exist within that function and cease to exist when you exit the function.

popen opens a new shell, as does system. You'll need to find a more persistent way to make those variable values available to your shell commands.

[Scorpions4ever]

Instead of using system() to shell out commands, why not look at the source code for ifconfig and grab the relevant lines to set your IP address.

A redhat distro comes with sources. If you don't have the CDs, you can try downloading the sources from the websites.

http://www.redhat.com/download/mirror.html
ftp://ftp.debian.org/debian/dists/woody/main/source/