313 lines
6.6 KiB
C
313 lines
6.6 KiB
C
/*
|
|
tcpd.c
|
|
*/
|
|
|
|
#include <sys/types.h>
|
|
#include <errno.h>
|
|
#include <fcntl.h>
|
|
#include <limits.h>
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include <unistd.h>
|
|
#include <signal.h>
|
|
#include <minix/config.h>
|
|
#include <minix/paths.h>
|
|
#include <sys/ioctl.h>
|
|
#include <sys/wait.h>
|
|
#include <net/hton.h>
|
|
#include <net/netlib.h>
|
|
#include <net/gen/in.h>
|
|
#include <net/gen/inet.h>
|
|
#include <netdb.h>
|
|
#include <net/gen/tcp.h>
|
|
#include <net/gen/tcp_io.h>
|
|
|
|
/* This program can be compiled to be paranoid, i.e. check incoming connection
|
|
* according to an access file, or to trust anyone. The much smaller "trust
|
|
* 'em" binary will call the paranoid version if the access file exists.
|
|
*/
|
|
|
|
static char *arg0, *service;
|
|
static unsigned nchildren;
|
|
|
|
static void report(const char *label)
|
|
{
|
|
int err= errno;
|
|
|
|
fprintf(stderr, "%s %s: %s: %s\n", arg0, service, label, strerror(err));
|
|
errno= err;
|
|
}
|
|
|
|
static void sigchld(int sig)
|
|
{
|
|
while (waitpid(-1, NULL, WNOHANG) > 0) {
|
|
if (nchildren > 0) nchildren--;
|
|
}
|
|
}
|
|
|
|
static void release(int *fd)
|
|
{
|
|
if (*fd != -1) {
|
|
close(*fd);
|
|
*fd= -1;
|
|
}
|
|
}
|
|
|
|
static void usage(void)
|
|
{
|
|
fprintf(stderr,
|
|
"Usage: %s [-d] [-m maxclients] service program [arg ...]\n",
|
|
arg0);
|
|
exit(1);
|
|
}
|
|
|
|
int main(int argc, char **argv)
|
|
{
|
|
tcpport_t port;
|
|
int last_failed = 0;
|
|
struct nwio_tcpcl tcplistenopt;
|
|
struct nwio_tcpconf tcpconf;
|
|
struct nwio_tcpopt tcpopt;
|
|
char *tcp_device;
|
|
struct servent *servent;
|
|
int tcp_fd, client_fd, r;
|
|
int pfd[2];
|
|
unsigned stall= 0;
|
|
struct sigaction sa;
|
|
sigset_t chldmask, chldunmask, oldmask;
|
|
char **progv;
|
|
|
|
#if !PARANOID
|
|
# define debug 0
|
|
# define max_children ((unsigned) -1)
|
|
arg0= argv[0];
|
|
|
|
/* Switch to the paranoid version of me if there are flags, or if
|
|
* there is an access file.
|
|
*/
|
|
if (argv[1][0] == '-' || access(_PATH_SERVACCES, F_OK) == 0) {
|
|
execv("/usr/bin/tcpdp", argv);
|
|
report("tcpdp");
|
|
exit(1);
|
|
}
|
|
if (argc < 3) usage();
|
|
service= argv[1];
|
|
progv= argv+2;
|
|
|
|
#else /* PARANOID */
|
|
int debug, i;
|
|
unsigned max_children;
|
|
|
|
arg0= argv[0];
|
|
debug= 0;
|
|
max_children= -1;
|
|
i= 1;
|
|
while (i < argc && argv[i][0] == '-') {
|
|
char *opt= argv[i++] + 1;
|
|
unsigned long m;
|
|
char *end;
|
|
|
|
if (*opt == '-' && opt[1] == 0) break; /* -- */
|
|
|
|
while (*opt != 0) switch (*opt++) {
|
|
case 'd':
|
|
debug= 1;
|
|
break;
|
|
case 'm':
|
|
if (*opt == 0) {
|
|
if (i == argc) usage();
|
|
opt= argv[i++];
|
|
}
|
|
m= strtoul(opt, &end, 10);
|
|
if (m <= 0 || m > UINT_MAX || *end != 0) usage();
|
|
max_children= m;
|
|
opt= "";
|
|
break;
|
|
default:
|
|
usage();
|
|
}
|
|
}
|
|
service= argv[i++];
|
|
progv= argv+i;
|
|
if (i >= argc) usage();
|
|
#endif
|
|
|
|
/* The interface to start the service on. */
|
|
if ((tcp_device= getenv("TCP_DEVICE")) == NULL) tcp_device= TCP_DEVICE;
|
|
|
|
/* Let SIGCHLD interrupt whatever I'm doing. */
|
|
sigemptyset(&chldmask);
|
|
sigaddset(&chldmask, SIGCHLD);
|
|
sigprocmask(SIG_BLOCK, &chldmask, &oldmask);
|
|
chldunmask= oldmask;
|
|
sigdelset(&chldunmask, SIGCHLD);
|
|
sigemptyset(&sa.sa_mask);
|
|
sa.sa_flags = 0;
|
|
sa.sa_handler = sigchld;
|
|
sigaction(SIGCHLD, &sa, NULL);
|
|
|
|
/* Open a socket to the service I'm to serve. */
|
|
if ((servent= getservbyname(service, "tcp")) == NULL) {
|
|
unsigned long p;
|
|
char *end;
|
|
|
|
p= strtoul(service, &end, 0);
|
|
if (p <= 0 || p > 0xFFFF || *end != 0) {
|
|
fprintf(stderr, "%s: %s: Unknown service\n",
|
|
arg0, service);
|
|
exit(1);
|
|
}
|
|
port= htons((tcpport_t) p);
|
|
} else {
|
|
port= servent->s_port;
|
|
|
|
if (debug)
|
|
{
|
|
fprintf(stderr, "%s %s: listening to port %u\n",
|
|
arg0, service, ntohs(port));
|
|
}
|
|
}
|
|
|
|
/* No client yet. */
|
|
client_fd= -1;
|
|
|
|
while (1) {
|
|
if ((tcp_fd= open(tcp_device, O_RDWR)) < 0) {
|
|
report(tcp_device);
|
|
#if 0
|
|
if (errno == ENOENT || errno == ENODEV
|
|
|| errno == ENXIO) {
|
|
exit(1);
|
|
}
|
|
#endif
|
|
last_failed = 1;
|
|
goto bad;
|
|
}
|
|
if(last_failed)
|
|
fprintf(stderr, "%s %s: %s: Ok\n",
|
|
arg0, service, tcp_device);
|
|
last_failed = 0;
|
|
|
|
tcpconf.nwtc_flags= NWTC_LP_SET | NWTC_UNSET_RA | NWTC_UNSET_RP;
|
|
tcpconf.nwtc_locport= port;
|
|
|
|
if (ioctl(tcp_fd, NWIOSTCPCONF, &tcpconf) < 0) {
|
|
report("Can't configure TCP channel");
|
|
exit(1);
|
|
}
|
|
|
|
tcpopt.nwto_flags= NWTO_DEL_RST;
|
|
|
|
if (ioctl(tcp_fd, NWIOSTCPOPT, &tcpopt) < 0) {
|
|
report("Can't set TCP options");
|
|
exit(1);
|
|
}
|
|
|
|
if (client_fd != -1) {
|
|
/* We have a client, so start a server for it. */
|
|
|
|
tcpopt.nwto_flags= 0;
|
|
(void) ioctl(client_fd, NWIOSTCPOPT, &tcpopt);
|
|
|
|
fflush(NULL);
|
|
|
|
/* Create a pipe to serve as an error indicator. */
|
|
if (pipe(pfd) < 0) {
|
|
report("pipe");
|
|
goto bad;
|
|
}
|
|
(void) fcntl(pfd[1], F_SETFD,
|
|
fcntl(pfd[1], F_GETFD) | FD_CLOEXEC);
|
|
|
|
/* Fork and exec. */
|
|
switch (fork()) {
|
|
case -1:
|
|
report("fork");
|
|
close(pfd[0]);
|
|
close(pfd[1]);
|
|
goto bad;
|
|
case 0:
|
|
close(tcp_fd);
|
|
close(pfd[0]);
|
|
#if PARANOID
|
|
/* Check if access to this service allowed. */
|
|
if (ioctl(client_fd, NWIOGTCPCONF, &tcpconf) == 0
|
|
&& tcpconf.nwtc_remaddr != tcpconf.nwtc_locaddr
|
|
&& !servxcheck(tcpconf.nwtc_remaddr, service, NULL)
|
|
) {
|
|
exit(1);
|
|
}
|
|
#endif
|
|
sigprocmask(SIG_SETMASK, &oldmask, NULL);
|
|
dup2(client_fd, 0);
|
|
dup2(client_fd, 1);
|
|
close(client_fd);
|
|
execvp(progv[0], progv);
|
|
report(progv[0]);
|
|
write(pfd[1], &errno, sizeof(errno));
|
|
exit(1);
|
|
default:
|
|
nchildren++;
|
|
release(&client_fd);
|
|
close(pfd[1]);
|
|
r= read(pfd[0], &errno, sizeof(errno));
|
|
close(pfd[0]);
|
|
if (r != 0) goto bad;
|
|
break;
|
|
}
|
|
}
|
|
|
|
while (nchildren >= max_children) {
|
|
/* Too many clients, wait for one to die off. */
|
|
sigsuspend(&chldunmask);
|
|
}
|
|
|
|
/* Wait for a new connection. */
|
|
sigprocmask(SIG_UNBLOCK, &chldmask, NULL);
|
|
|
|
tcplistenopt.nwtcl_flags= 0;
|
|
while (ioctl(tcp_fd, NWIOTCPLISTEN, &tcplistenopt) < 0) {
|
|
if (errno != EINTR) {
|
|
if (errno != EAGAIN || debug) {
|
|
report("Unable to listen");
|
|
}
|
|
goto bad;
|
|
}
|
|
}
|
|
sigprocmask(SIG_BLOCK, &chldmask, NULL);
|
|
|
|
/* We got a connection. */
|
|
client_fd= tcp_fd;
|
|
tcp_fd= -1;
|
|
|
|
if (debug && ioctl(client_fd, NWIOGTCPCONF, &tcpconf) == 0) {
|
|
fprintf(stderr, "%s %s: Connection from %s:%u\n",
|
|
arg0, service,
|
|
inet_ntoa(tcpconf.nwtc_remaddr),
|
|
ntohs(tcpconf.nwtc_remport));
|
|
}
|
|
/* All is well, no need to stall. */
|
|
stall= 0;
|
|
continue;
|
|
|
|
bad:
|
|
/* All is not well, release resources. */
|
|
release(&tcp_fd);
|
|
release(&client_fd);
|
|
|
|
/* Wait a bit if this happens more than once. */
|
|
if (stall != 0) {
|
|
if (debug) {
|
|
fprintf(stderr, "%s %s: stalling %u second%s\n",
|
|
arg0, service,
|
|
stall, stall == 1 ? "" : "s");
|
|
}
|
|
sleep(stall);
|
|
stall <<= 1;
|
|
} else {
|
|
stall= 1;
|
|
}
|
|
}
|
|
}
|