#include <u.h>#include <libc.h>#include <bio.h>#include <auth.h> /* * called by listen as rexexec rexexec net dir ... */voidmain(int argc, char **argv){	char buf[8192];	int n, nn;	AuthInfo *ai; 	ARGBEGIN{	}ARGEND; 	ai = auth_proxy(0, auth_getkey, "proto=p9any role=server");	if(ai == nil)		sysfatal("auth_proxy: %r");	if(strcmp(ai->cuid, "none") == 0)		sysfatal("rexexec by none disallowed");	if(auth_chuid(ai, nil) < 0)		sysfatal("auth_chuid: %r"); 	n = 0;	do {		nn = read(0, buf+n, 1);		if(nn <= 0)			sysfatal("can't read command");		n += nn;		if(n == sizeof buf)			buf[n-1] = '\0';	} while (buf[n-1] != '\0'); 	putenv("service", "rx");	execl("/bin/rc", "rc", "-lc", buf, nil);	sysfatal("can't exec rc");}