/*

stupid-ftpd.c

------------

Main program. Bind/Listen/Accept routines.

*/

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <ctype.h>

#include <errno.h>

#include <signal.h>

#ifdef __CYGWIN__

#include <winsock2.h>

#else

#include <unistd.h>

#include <sys/socket.h>

#include <netinet/in.h>

#include <netdb.h>

#define INVALID_SOCKET -1

#endif

#include <sys/wait.h>

#include <time.h>

#include <sys/time.h>

#include "stupid-ftpd.h"

#include "ftpdconfig.h"

#include "ftpcommand.h"

#include "servercommand.h"

#include "ftperror.h"

#include "ls.h"

#define REACTION_TIME 1L

child_t *pchild[HARD_USERLIMIT];

int server_socket=0;

int serverstop=0;

int reinit=1;

/* prototypes */

void init_login(void);

void check_timeouts(void);

void cleanchild(int);

void listener_loop(void);

void startserver(void);

int process_banned(int,char *);

void do_changeroot(void);

void do_writepidfile(void);

int process_banned(int sock,char *host) {

int n;

char buffer[128];

for (n=0;n<bancount;n++)

if (list_match(host,banlist[n])) {

#ifdef DEBUG

fprintf(stderr,"Ban hit '%s'\n",host);

#endif

if (banmessage[0]!=0) {

sprintf(buffer,"540 %s\r\n",banmessage);

write(sock,buffer,strlen(buffer));

}

close(sock);

return 1;

}

return 0;

}

void init_login(void) {

int nr,sock,sock_size;

char buffer[128];

struct sockaddr_in sa;

struct hostent *hp;

unsigned char *i;

sock_size=sizeof(sa);

if ((sock=accept(server_socket,(struct sockaddr *)&sa,&sock_size))<0) {

if (!daemonmode)

printf("Error: accept failed.\n");

return;

}

for (nr=0;nr<maxusers;nr++)

if (!pchild[nr]->sock) break;

if (nr>=maxusers) {

if (!daemonmode) {

printf("Info: Server is full.\n");

out_prompt();

}

sprintf(buffer,"530 Server is busy, sorry.\r\n");

write(sock,buffer,strlen(buffer));

close(sock);

return;

}

i=(unsigned char *)&sa.sin_addr;

pchild[nr]->userip[0]=*i++;

pchild[nr]->userip[1]=*i++;

pchild[nr]->userip[2]=*i++;

pchild[nr]->userip[3]=*i++;

sprintf(buffer,"%d.%d.%d.%d",

pchild[nr]->userip[0],pchild[nr]->userip[1],

pchild[nr]->userip[2],pchild[nr]->userip[3]);

if (process_banned(sock,buffer)) return;

hp=gethostbyaddr((char *)&sa.sin_addr,sizeof(long int),AF_INET);

if (hp!=NULL) {

strncpy(pchild[nr]->url,hp->h_name,sizeof(pchild[nr]->url)-1);

*(pchild[nr]->url+strlen(hp->h_name))=0;

} else strcpy(pchild[nr]->url,"unknown");

if (process_banned(sock,pchild[nr]->url)) return;

pchild[nr]->sock=sock;

pchild[nr]->idletime=time(NULL);

strcpy(pchild[nr]->reldir,"/");

strcpy(pchild[nr]->rootdir,"???*???"); /* better */

pchild[nr]->state=USR_USER;

pchild[nr]->resume=0;

pchild[nr]->pasvsock=0;

pchild[nr]->pid=0;

pchild[nr]->dataport=0;

pchild[nr]->perm=PERM_NONE;

if (!daemonmode) {

printf("User %d, connected (IP: %d.%d.%d.%d).\n",nr+1,

pchild[nr]->userip[0],

pchild[nr]->userip[1],

pchild[nr]->userip[2],

pchild[nr]->userip[3]);

out_prompt();

}

user_return(nr,RET_220);

}

void check_timeouts(void)

{

int n;

time_t t;

/* check the timeouts of all 3 phases */

t=time(NULL);

for (n=0;n<maxusers;n++) {

if (pchild[n]->sock) {

switch (pchild[n]->state) {

case USR_ONLINE:

if (pchild[n]->pid==0 || waitpid(pchild[n]->pid,NULL,WNOHANG)<0) {

pchild[n]->pid=0;

if (t-pchild[n]->idletime>=idletimeout) {

handle_timeout(n);

}

} else pchild[n]->idletime=t;

break;

case USR_USER:

case USR_PASS:

if (t-pchild[n]->idletime>=logintimeout) handle_timeout(n);

break;

default: /* better */

handle_suspects(n);

break;

}

}

}

}

void cleanchild(int nr) {

#ifdef WAIT_DEBUG

pid_t proc;

fprintf(stderr,"\nEntered in cleanchild\n");

while ((proc=wait3(NULL, WNOHANG, NULL)) > 0);

fprintf(stderr,"\nLeft cleanchild\n");

#else

while (wait3(NULL, WNOHANG, NULL) > 0);

#endif

#ifdef __SVR4

sigset(SIGCHLD,cleanchild);

#else

signal(SIGCHLD,cleanchild);

#endif

}

void listener_loop(void)

{

int i,n,addr;

unsigned int sock_size;

fd_set fds;

struct timeval tv;

char cmd[1024];

struct sockaddr_in sa;

#ifdef __CYGWIN__

WORD verreq;

WSADATA wsadata;

#endif

/* catch broken pipe ! */

#ifdef __SVR4

sigignore(SIGPIPE);

sigset(SIGCHLD,cleanchild);

#else

signal(SIGPIPE,SIG_IGN);

signal(SIGCHLD,cleanchild);

#endif

/*

myip=getmyip();

if (myip==NULL) {

printf("Determining localhost-IP failed.\n");

exit(1);

}

#ifdef DEBUG

printf("My IP is: %d.%d.%d.%d\n",

myip[0],myip[1],myip[2],myip[3]);

#endif

*/

/* server init */

#ifdef __CYGWIN__

verreq=MAKEWORD(1,1);

i=WSAStartup(verreq,&wsadata);

if (i!=0) {

printf("Error: winsock-lib couldn't be initialized.");

}

#endif

if (!daemonmode)

printf("Starting server ... ");

if ((server_socket=socket(PF_INET,SOCK_STREAM,0))==INVALID_SOCKET) {

#ifdef __CYGWIN__

i=WSAGetLastError();

#else

i=errno;

#endif

printf("Error: could not create server socket (%d).\n",i);

exit(1);

}

i=1;

if (setsockopt(server_socket,SOL_SOCKET,SO_REUSEADDR,(void *)&i,sizeof(i))<0)

printf("setsockopt failed.\n");

sock_size=sizeof(struct sockaddr_in);

memset(&sa,0,sock_size);

sa.sin_family=PF_INET;

sa.sin_port=htons(serverport);

addr=INADDR_ANY;

memcpy(&sa.sin_addr.s_addr,&addr,sizeof(int));

if (bind(server_socket,(struct sockaddr *)&sa,sock_size)<0) {

printf("Error: bind failed.\n");

printf(" port %i already in use ?\n",serverport);

exit(1);

}

if (listen(server_socket,5)<0) {

printf("Error: listen failed.\n");

exit(1);

}

if (!daemonmode) {

printf("OK\n\n");

out_prompt();

}

#ifdef DEBUG

printf("Listening ...\n");

#endif

serverstop=0;

while (!serverstop) {

FD_ZERO(&fds);

if (!daemonmode) FD_SET(1,&fds);

FD_SET(server_socket,&fds);

for (i=0;i<maxusers;i++)

if (pchild[i]->sock)

FD_SET(pchild[i]->sock,&fds);

/* memset(&tv,0,sizeof(struct timeval)); */

tv.tv_sec=REACTION_TIME;tv.tv_usec=0L;

n=select(32+maxusers*4,&fds,NULL,NULL,&tv);

if (n<0) {

if (errno==EINTR) continue;

if (

#ifdef __CYGWIN__

1) {

i=WSAGetLastError();

#else

!daemonmode) {

i=errno;

#endif

fprintf(stderr,"*** Fehler: select (ret: %d,errno=%d).\n",n,i);

}

exit(1);

}

if (!daemonmode)

if (FD_ISSET(1,&fds)) {

i=read(1,cmd,sizeof(cmd));

if (i<1) continue;

cmd[i-1]=0;

execcmd(cmd);

if (serverstop) break;

out_prompt();

}

if (FD_ISSET(server_socket,&fds)) init_login();

for (i=0;i<maxusers;i++) {

if (pchild[i]->sock) {

if (FD_ISSET(pchild[i]->sock,&fds))

serve_child(i);

}

}

check_timeouts();

}

close(server_socket);

#ifdef __CYGWIN__

WSACleanup();

#endif

if (!daemonmode)

printf("Server stopped.\n");

}

void startserver(void)

{

int n;

if (logfile) fprintf(logfile,"Server restarted.\n");

for (n=0;n<maxusers;n++) {

pchild[n]=(child_t *)malloc(sizeof(child_t));

pchild[n]->sock=0;

}

listener_loop();

}

void do_writepidfile() {

/* PID-file processing */

if ( fpid != NULL ) {

fprintf(fpid,"%d\n",(int)getpid());

fflush(fpid);

fclose(fpid);

}

}

void do_changeroot() {

if (realchangeroot) {

if (getuid()!=0) {

realchangeroot=0;

if (!daemonmode) printf("Chroot only works with root privileges.\n");

return;

}

chdir(serverroot);

chroot(serverroot);

}

}

int main(int argc,char **argv)

{

int n;

for (n=0;n<HARD_USERLIMIT;n++)

pchild[n]=(child_t *)NULL;

for (n=0;n<LOGININFO_COUNT;n++)

logininfo[n]=(logininfo_t *)NULL;

parsecmdline(argc,argv);

while (reinit) {

reinit=0;

preinit();

if (readini()<0) exit(1);

if (!checkconf()) exit(1);

do_writepidfile();

do_changeroot();

if (daemonmode) {

if (fork()==0) startserver();

exit(0); /* better be sure */

} else startserver();

for (n=0;n<maxusers;n++)

if (pchild[n]) {

free(pchild[n]);

pchild[n]=(child_t *)NULL;

}

for (n=0;n<logininfocount;n++)

if (logininfo[n]) {

free(logininfo[n]);

logininfo[n]=(logininfo_t *)NULL;

}

}

exit(0);

}