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<title>/usr/web/sources/contrib/cinap_lenrek/tftpd.c - Plan 9 from Bell Labs</title>


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<a href="/plan9/">Plan 9 from Bell Labs</a>’s /usr/web/sources/contrib/cinap_lenrek/tftpd.c


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Copyright © 2009 Alcatel-Lucent. 
Distributed under the
<a href="/plan9/license.html">Lucent Public License version 1.02</a>.
 
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#include <u.h>
#include <libc.h>
#include <auth.h>
#include <bio.h>
#include <ip.h>
#include <ndb.h>

enum
{
Maxpath= 128,
Maxerr= 256,
};

int dbg;
int restricted;
void sendfile(int, char*, char*);
void recvfile(int, char*, char*);
void nak(int, int, char*);
void oack(int, char*, char*);
void ack(int, ushort);
void clrcon(void);
void setuser(void);
char* sunkernel(char*);
void remoteaddr(char*, char*, int);
void doserve(int);

char bigbuf[32768];
char raddr[64];

char *dir = "/lib/tftpd";
char *dirsl;
int dirsllen;
char flog[] = "ipboot";
char net[Maxpath];

enum
{
Tftp_READ = 1,
Tftp_WRITE = 2,
Tftp_DATA = 3,
Tftp_ACK = 4,
Tftp_ERROR = 5,
Tftp_OACK = 6,
Segsize = 512,
};

void
usage(void)
{
fprint(2, "usage: %s [-dr] [-h homedir] [-s svc] [-x netmtpt]\n",
argv0);
exits("usage");
}

int
getlist(char *buf, int nbuf, char **list, int nlist)
{
int s, c;
char *p;

p = nil;
c = 0;
s = 0;
while(nbuf-- > 0){
switch(s){
case 0:
p = buf;
s = 1;

case 1:
if(*buf == '\0'){
s = 0;
if(--nlist <= 0)
goto outout;
*list = p;
list++;
c++;
}
break;
}
buf++;
}
outout:
*list = nil;
return c;
}

void
main(int argc, char **argv)
{
char buf[64];
char adir[64], ldir[64];
int cfd, lcfd, dfd;
char *p, *svc = "69";

setnetmtpt(net, sizeof(net), nil);
ARGBEGIN{
case 'd':
dbg++;
break;
case 'h':
dir = ARGF();
break;
case 'r':
restricted = 1;
break;
case 's':
svc = EARGF(usage());
break;
case 'x':
p = ARGF();
if(p == nil)
usage();
setnetmtpt(net, sizeof(net), p);
break;
default:
usage();
}ARGEND

snprint(buf, sizeof buf, "%s/", dir);
dirsl = strdup(buf);
dirsllen = strlen(dirsl);

fmtinstall('E', eipfmt);
fmtinstall('I', eipfmt);

if(chdir(dir) < 0)
sysfatal("can't get to directory %s: %r", dir);

if(!dbg)
switch(rfork(RFNOTEG|RFPROC|RFFDG)) {
case -1:
sysfatal("fork: %r");
case 0:
break;
default:
exits(0);
}

snprint(buf, sizeof buf, "%s/udp!*!%s", net, svc);
cfd = announce(buf, adir);
if (cfd < 0)
sysfatal("announcing on %s: %r", buf);
syslog(dbg, flog, "tftpd started on %s dir %s", buf, adir);
setuser();
for(;;) {
lcfd = listen(adir, ldir);
if(lcfd < 0)
sysfatal("listening on %s: %r", adir);

switch(fork()) {
case -1:
sysfatal("fork: %r");
case 0:
dfd = accept(lcfd, ldir);
if(dfd < 0)
exits(0);
remoteaddr(ldir, raddr, sizeof(raddr));
syslog(0, flog, "tftp connection from %s dir %s",
raddr, ldir);
doserve(dfd);
exits("done");
break;
default:
close(lcfd);
continue;
}
}
}

void
doserve(int fd)
{
int dlen;
char *field[10];
char tmp[128];
int nfield;
char *name, *mode;
char **opt;
short op;
Dir *dir;

dlen = read(fd, bigbuf, sizeof(bigbuf));
if(dlen < 0)
sysfatal("listen read: %r");

op = (bigbuf[0]<<8) | bigbuf[1];
dlen -= 2;

nfield = getlist(bigbuf+2, dlen, field, sizeof(field)/sizeof(field[0]));
if(nfield < 2){
nak(fd, 0, "bad request");
close(fd);
syslog(dbg, flog, "bad request from %s", raddr);
return;
}
name = field[0];
mode = field[1];
if(op != Tftp_READ && op != Tftp_WRITE) {
nak(fd, 4, "Illegal TFTP operation");
close(fd);
syslog(dbg, flog, "bad request %d %s", op, raddr);
return;
}

/*
if(restricted){
if(*name == '#' ||
strncmp(name, "../", 3)==0 || strstr(name) ||
(*name == '/' && strncmp(name, dirsl, dirsllen)!=0)){
nak(fd, 4, "Permission denied");
close(fd);
syslog(dbg, flog, "bad request %d from %s file %s", op, raddr, name);
return;
}
}*/

name = sunkernel(name);
if(name == 0){
nak(fd, 0, "file not found");
close(fd);
syslog(dbg, flog, "file %s not found for %s", name, raddr);
return;
}

if((nfield>2) && ((nfield%2)==0)){
/* handle options */
nfield -= 2;
nfield /= 2;
opt = &field[2];
while(nfield-- > 0){
if(cistrcmp(opt[0], "tsize")==0){
if(op == Tftp_READ){
dir=dirstat(name);
if(dir != nil){
snprint(tmp, sizeof(tmp), "%lld", dir->length);
free(dir);
oack(fd, opt[0], tmp);
}
}
}
opt+=2;
}
}

if(op == Tftp_READ)
sendfile(fd, name, mode);
else
recvfile(fd, name, mode);
}

void
catcher(void *junk, char *msg)
{
USED(junk);

if(strncmp(msg, "exit", 4) == 0)
noted(NDFLT);
noted(NCONT);
}

void
sendfile(int fd, char *name, char *mode)
{
int file;
uchar buf[Segsize+4];
uchar ack[1024];
char errbuf[Maxerr];
int ackblock, block, ret;
int rexmit, n, al, txtry, rxl;
short op;

syslog(dbg, flog, "send file '%s' %s to %s", name, mode, raddr);
if(name == 0){
nak(fd, 0, "not in our database");
return;
}

notify(catcher);

file = open(name, OREAD);
if(file < 0) {
errstr(errbuf, sizeof errbuf);
nak(fd, 0, errbuf);
return;
}
block = 0;
rexmit = 0;
n = 0;
for(txtry = 0; txtry < 5;) {
if(rexmit == 0) {
block++;
buf[0] = 0;
buf[1] = Tftp_DATA;
buf[2] = block>>8;
buf[3] = block;
n = read(file, buf+4, Segsize);
if(n < 0) {
errstr(errbuf, sizeof errbuf);
nak(fd, 0, errbuf);
return;
}
txtry = 0;
}
else {
syslog(dbg, flog, "rexmit %d %s:%d to %s", 4+n, name, block, raddr);
txtry++;
}

ret = write(fd, buf, 4+n);
if(ret < 0)
sysfatal("tftpd: network write error: %r");

for(rxl = 0; rxl < 10; rxl++) {
rexmit = 0;
alarm(500);
al = read(fd, ack, sizeof(ack));
alarm(0);
if(al < 0) {
rexmit = 1;
break;
}
op = ack[0]<<8|ack[1];
if(op == Tftp_ERROR)
goto error;
ackblock = ack[2]<<8|ack[3];
if(ackblock == block)
break;
if(ackblock == 0xffff) {
rexmit = 1;
break;
}
}
if(ret != Segsize+4 && rexmit == 0)
break;
}
error:
close(fd);
close(file);
}

void
recvfile(int fd, char *name, char *mode)
{
ushort op, block, inblock;
uchar buf[Segsize+8];
char errbuf[Maxerr];
int n, ret, file;

syslog(dbg, flog, "receive file '%s' %s from %s", name, mode, raddr);

file = create(name, OWRITE, 0666);
if(file < 0) {
errstr(errbuf, sizeof errbuf);
nak(fd, 0, errbuf);
return;
}

block = 0;
ack(fd, block);
block++;

for(;;) {
alarm(15000);
n = read(fd, buf, sizeof(buf));
alarm(0);
if(n < 0)
goto error;
op = buf[0]<<8|buf[1];
if(op == Tftp_ERROR)
goto error;

n -= 4;
inblock = buf[2]<<8|buf[3];
if(op == Tftp_DATA) {
if(inblock == block) {
ret = write(file, buf, n);
if(ret < 0) {
errstr(errbuf, sizeof errbuf);
nak(fd, 0, errbuf);
goto error;
}
ack(fd, block);
block++;
}
ack(fd, 0xffff);
}
}
error:
close(file);
}

void
ack(int fd, ushort block)
{
uchar ack[4];
int n;

ack[0] = 0;
ack[1] = Tftp_ACK;
ack[2] = block>>8;
ack[3] = block;

n = write(fd, ack, 4);
if(n < 0)
sysfatal("network write: %r");
}

void
oack(int fd, char *option, char *value)
{
char buf[128];
int l1, l2, n;

buf[0] = 0;
buf[1] = Tftp_OACK;

l1=strlen(option);
l2=strlen(value);
n = 2 + l1+1 + l2+1;

if(n < sizeof(buf)){
memcpy(buf+2, option, l1+1);
memcpy(buf+2+l1+1, value, l2+1);
n = write(fd, buf, n);
if(n < 0)
sysfatal("write oack: %r");
}
}

void
nak(int fd, int code, char *msg)
{
char buf[128];
int n;

buf[0] = 0;
buf[1] = Tftp_ERROR;
buf[2] = 0;
buf[3] = code;
strcpy(buf+4, msg);
n = strlen(msg) + 4 + 1;
n = write(fd, buf, n);
if(n < 0)
sysfatal("write nak: %r");
}

void
setuser(void)
{
int fd;

fd = open("#c/user", OWRITE);
if(fd < 0 || write(fd, "none", strlen("none")) < 0)
sysfatal("can't become none: %r");
close(fd);
if(newns("none", nil) < 0)
sysfatal("can't build namespace: %r");
bind(dir, "/", MAFTER);
}

char*
lookup(char *sattr, char *sval, char *tattr, char *tval, int len)
{
static Ndb *db;
char *attrs[1];
Ndbtuple *t;

if(db == nil)
db = ndbopen(0);
if(db == nil)
return nil;

if(sattr == nil)
sattr = ipattr(sval);

attrs[0] = tattr;
t = ndbipinfo(db, sattr, sval, attrs, 1);
if(t == nil)
return nil;
strncpy(tval, t->val, len);
tval[len-1] = 0;
ndbfree(t);
return tval;
}

/*
* for sun kernel boots, replace the requested file name with
* a one from our database. If the database doesn't specify a file,
* don't answer.
*/
char*
sunkernel(char *name)
{
ulong addr;
uchar v4[IPv4addrlen];
uchar v6[IPaddrlen];
char buf[256];
char ipbuf[128];
char *suffix;

addr = strtoul(name, &suffix, 16);
if(suffix-name != 8 || (strcmp(suffix, "") != 0 && strcmp(suffix, ".SUN") != 0))
return name;

v4[0] = addr>>24;
v4[1] = addr>>16;
v4[2] = addr>>8;
v4[3] = addr;
v4tov6(v6, v4);
sprint(ipbuf, "%I", v6);
return lookup("ip", ipbuf, "bootf", buf, sizeof buf);
}

void
remoteaddr(char *dir, char *raddr, int len)
{
char buf[64];
int fd, n;

snprint(buf, sizeof(buf), "%s/remote", dir);
fd = open(buf, OREAD);
if(fd < 0){
snprint(raddr, sizeof(raddr), "unknown");
return;
}
n = read(fd, raddr, len-1);
close(fd);
if(n <= 0){
snprint(raddr, sizeof(raddr), "unknown");
return;
}
if(n > 0)
n--;
raddr[n] = 0;
}

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