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execute(args, sin, sout, serr)
char **args;
int sin, sout, serr;
{
int pid, status;
/*
* Get a child process.
*/
if ((pid = fork()) < 0) {
perror("fork");
exit(1);
}
/*
* The child executes the code inside the if.
*/
if (pid == 0) {
/*
* For each of standard input, output,
* and error output, set the child's
* to the passed-down file descriptor.
* Note that we can't just close 0, 1,
* and 2 since we might need them.
*/
if (sin != 0) {
close(0);
dup(sin); /* will give us fd #0 */
}
if (sout != 1) {
close(1);
dup(sout); /* will give us fd #1 */
}
if (serr != 2) {
close(2);
dup(serr); /* will give us fd #2 */
}
execvp(*args, args);
perror(*args);
exit(1);
}
/*
* The parent executes the wait.
*/
while (wait(&status) != pid)
/* empty loop */;
}
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