/*

* (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.

* See the copyright notice in the ACK home directory, in the file "Copyright".

*/

/* $Header$ */

#if defined(_POSIX_SOURCE)

#include <sys/types.h>

#endif

#include <stdlib.h>

#include <signal.h>

extern pid_t _fork(void);

extern pid_t _wait(int *);

extern void _exit(int);

extern void _execve(const char *path, const char ** argv, const char ** envp);

extern int _close(int);

#define FAIL 127

extern const char ***_penviron;

static const char *exec_tab[] = {

"sh", /* argv[0] */

"-c", /* argument to the shell */

NULL, /* to be filled with user command */

NULL /* terminating NULL */

};

int

system(const char *str)

{

int pid, exitstatus, waitval;

int i;

if ((pid = _fork()) < 0) return str ? -1 : 0;

if (pid == 0) {

for (i = 3; i <= 20; i++)

_close(i);

if (!str) str = "cd ."; /* just testing for a shell */

exec_tab[2] = str; /* fill in command */

_execve("/bin/sh", exec_tab, *_penviron);

/* get here if execve fails ... */

_exit(FAIL); /* see manual page */

}

while ((waitval = _wait(&exitstatus)) != pid) {

if (waitval == -1) break;

}

if (waitval == -1) {

/* no child ??? or maybe interrupted ??? */

exitstatus = -1;

}

if (!str) {

if (exitstatus == FAIL << 8) /* execve() failed */

exitstatus = 0;

else exitstatus = 1; /* /bin/sh exists */

}

return exitstatus;

}