ref: 19d6a98038953b27f539e1fd2187b7cfec9b108d
dir: /sys/src/cmd/exportfs/exportfs.c/
/*
* exportfs - Export a plan 9 name space across a network
*/
#include <u.h>
#include <libc.h>
#include <auth.h>
#include <fcall.h>
#include <libsec.h>
#define Extern
#include "exportfs.h"
#define QIDPATH ((1LL<<48)-1)
vlong newqid = 0;
enum {
Encnone,
Encssl,
Enctls,
};
void (*fcalls[])(Fsrpc*) =
{
[Tversion] Xversion,
[Tauth] Xauth,
[Tflush] Xflush,
[Tattach] Xattach,
[Twalk] Xwalk,
[Topen] slave,
[Tcreate] Xcreate,
[Tclunk] Xclunk,
[Tread] slave,
[Twrite] slave,
[Tremove] Xremove,
[Tstat] Xstat,
[Twstat] Xwstat,
};
/* accounting and debugging counters */
int filecnt;
int freecnt;
int qidcnt;
int qfreecnt;
int ncollision;
int srvfd = -1;
int nonone = 1;
char *filterp;
char *ealgs = "rc4_256 sha1";
char *aanfilter = "/bin/aan";
int encproto = Encnone;
int readonly;
static void mksecret(char *, uchar *);
static char *anstring = "tcp!*!0";
char *netdir = "", *local = "", *remote = "";
void filter(int, char *, char *);
void
usage(void)
{
fprint(2, "usage: %s [-adnsR] [-f dbgfile] [-m msize] [-r root] "
"[-S srvfile] [-e 'crypt hash'] [-P exclusion-file] "
"[-A announce-string] [-B address]\n", argv0);
fatal("usage");
}
static void
noteconn(int fd)
{
NetConnInfo *nci;
nci = getnetconninfo(nil, fd);
if(nci == nil)
return;
netdir = estrdup(nci->dir);
local = estrdup(nci->lsys);
remote = estrdup(nci->rsys);
freenetconninfo(nci);
}
void
main(int argc, char **argv)
{
char buf[ERRMAX], ebuf[ERRMAX], initial[4], *ini, *srvfdfile;
char *dbfile, *srv, *na, *nsfile, *keyspec;
int doauth, n, fd;
AuthInfo *ai;
Fsrpc *r;
dbfile = "/tmp/exportdb";
srv = nil;
srvfd = -1;
srvfdfile = nil;
na = nil;
nsfile = nil;
keyspec = "";
doauth = 0;
ai = nil;
ARGBEGIN{
case 'a':
doauth = 1;
break;
case 'd':
dbg++;
break;
case 'e':
ealgs = EARGF(usage());
if(*ealgs == 0 || strcmp(ealgs, "clear") == 0)
ealgs = nil;
break;
case 'f':
dbfile = EARGF(usage());
break;
case 'k':
keyspec = EARGF(usage());
break;
case 'm':
messagesize = strtoul(EARGF(usage()), nil, 0);
break;
case 'n':
nonone = 0;
break;
case 'r':
srv = EARGF(usage());
break;
case 's':
srv = "/";
break;
case 'A':
anstring = EARGF(usage());
break;
case 'B':
na = EARGF(usage());
break;
case 'F':
/* accepted but ignored, for backwards compatibility */
break;
case 'N':
nsfile = EARGF(usage());
break;
case 'P':
patternfile = EARGF(usage());
break;
case 'R':
readonly = 1;
break;
case 'S':
if(srvfdfile != nil)
usage();
srvfdfile = EARGF(usage());
break;
default:
usage();
}ARGEND
USED(argc, argv);
if(na == nil && doauth){
/*
* We use p9any so we don't have to visit this code again, with the
* cost that this code is incompatible with the old world, which
* requires p9sk2. (The two differ in who talks first, so compatibility
* is awkward.)
*/
ai = auth_proxy(0, auth_getkey, "proto=p9any role=server %s", keyspec);
if(ai == nil)
fatal("auth_proxy: %r");
if(nonone && strcmp(ai->cuid, "none") == 0)
fatal("exportfs by none disallowed");
if(auth_chuid(ai, nsfile) < 0)
fatal("auth_chuid: %r");
putenv("service", "exportfs");
}
if(srvfdfile != nil){
if((srvfd = open(srvfdfile, ORDWR)) < 0)
fatal("open %s: %r", srvfdfile);
}
if(na != nil){
if(srv == nil)
fatal("-B requires -s");
local = "me";
remote = na;
if((fd = dial(netmkaddr(na, 0, "importfs"), 0, 0, 0)) < 0)
fatal("can't dial %s: %r", na);
ai = auth_proxy(fd, auth_getkey, "proto=p9any role=client %s", keyspec);
if(ai == nil)
fatal("%r: %s", na);
dup(fd, 0);
dup(fd, 1);
close(fd);
}
exclusions();
if(dbg) {
n = create(dbfile, OWRITE|OTRUNC, 0666);
dup(n, DFD);
close(n);
}
if(srvfd >= 0 && srv != nil){
fprint(2, "exportfs: -S cannot be used with -r or -s\n");
usage();
}
DEBUG(DFD, "exportfs: started\n");
rfork(RFNOTEG|RFREND);
if(messagesize == 0){
messagesize = iounit(0);
if(messagesize == 0)
messagesize = 8192+IOHDRSZ;
}
fhash = emallocz(sizeof(Fid*)*FHASHSIZE);
fmtinstall('F', fcallfmt);
/*
* Get tree to serve from network connection,
* check we can get there and ack the connection
*/
if(srvfd != -1) {
/* do nothing */
}
else if(srv != nil) {
if(chdir(srv) < 0) {
ebuf[0] = '\0';
errstr(ebuf, sizeof ebuf);
r = getsbuf();
r->work.tag = NOTAG;
r->work.fid = NOFID;
r->work.type = Rerror;
r->work.ename = ebuf;
n = convS2M(&r->work, r->buf, messagesize);
write(0, r->buf, n);
DEBUG(DFD, "chdir(\"%s\"): %s\n", srv, ebuf);
exits(ebuf);
}
DEBUG(DFD, "invoked as server for %s", srv);
strncpy(buf, srv, sizeof buf);
}
else {
noteconn(0);
buf[0] = 0;
n = read(0, buf, sizeof(buf)-1);
if(n < 0) {
errstr(buf, sizeof buf);
fprint(0, "read(0): %s\n", buf);
DEBUG(DFD, "read(0): %s\n", buf);
exits(buf);
}
buf[n] = 0;
if(chdir(buf) < 0) {
errstr(ebuf, sizeof ebuf);
fprint(0, "chdir(%d:\"%s\"): %s\n", n, buf, ebuf);
DEBUG(DFD, "chdir(%d:\"%s\"): %s\n", n, buf, ebuf);
exits(ebuf);
}
}
DEBUG(DFD, "\niniting root\n");
initroot();
DEBUG(DFD, "exportfs: %s\n", buf);
if(srv == nil && srvfd == -1 && write(0, "OK", 2) != 2)
fatal("open ack write");
ini = initial;
n = readn(0, initial, sizeof(initial));
if(n == 0)
fatal(nil); /* port scan or spurious open/close on exported /srv file (unmount) */
if(n < sizeof(initial))
fatal("can't read initial string: %r");
if(memcmp(ini, "impo", 4) == 0) {
char buf[128], *p, *args[3];
ini = nil;
p = buf;
for(;;){
if((n = read(0, p, 1)) < 0)
fatal("can't read impo arguments: %r");
if(n == 0)
fatal("connection closed while reading arguments");
if(*p == '\n')
*p = '\0';
if(*p++ == '\0')
break;
if(p >= buf + sizeof(buf))
fatal("import parameters too long");
}
if(tokenize(buf, args, nelem(args)) != 2)
fatal("impo arguments invalid: impo%s...", buf);
if(strcmp(args[0], "aan") == 0)
filterp = aanfilter;
else if(strcmp(args[0], "nofilter") != 0)
fatal("import filter argument unsupported: %s", args[0]);
if(strcmp(args[1], "ssl") == 0)
encproto = Encssl;
else if(strcmp(args[1], "tls") == 0)
encproto = Enctls;
else if(strcmp(args[1], "clear") != 0)
fatal("import encryption proto unsupported: %s", args[1]);
if(encproto == Enctls)
fatal("%s: tls has not yet been implemented", argv[0]);
}
if(encproto != Encnone && ealgs != nil && ai != nil) {
uchar key[16], digest[SHA1dlen];
char fromclientsecret[21];
char fromserversecret[21];
int i;
if(ai->nsecret < 8)
fatal("secret too small for ssl");
memmove(key+4, ai->secret, 8);
/* exchange random numbers */
srand(truerand());
for(i = 0; i < 4; i++)
key[i+12] = rand();
if(ini != nil)
fatal("Protocol botch: old import");
if(readn(0, key, 4) != 4)
fatal("can't read key part; %r");
if(write(0, key+12, 4) != 4)
fatal("can't write key part; %r");
/* scramble into two secrets */
sha1(key, sizeof(key), digest, nil);
mksecret(fromclientsecret, digest);
mksecret(fromserversecret, digest+10);
if(filterp != nil)
filter(0, filterp, na);
switch(encproto) {
case Encssl:
fd = pushssl(0, ealgs, fromserversecret, fromclientsecret, nil);
if(fd < 0)
fatal("can't establish ssl connection: %r");
if(fd != 0){
dup(fd, 0);
close(fd);
}
break;
case Enctls:
default:
fatal("Unsupported encryption protocol");
}
}
else if(filterp != nil) {
if(ini != nil)
fatal("Protocol botch: don't know how to deal with this");
filter(0, filterp, na);
}
dup(0, 1);
if(ai != nil)
auth_freeAI(ai);
if(ini != nil){
r = getsbuf();
memmove(r->buf, ini, BIT32SZ);
n = GBIT32(r->buf);
if(n <= BIT32SZ || n > messagesize)
fatal("bad length in 9P2000 message header");
n -= BIT32SZ;
if(readn(0, r->buf+BIT32SZ, n) != n)
fatal(nil);
n += BIT32SZ;
goto Message;
}
/*
* Start serving file requests from the network
*/
for(;;) {
r = getsbuf();
n = read9pmsg(0, r->buf, messagesize);
if(n <= 0)
fatal(nil);
Message:
if(convM2S(r->buf, n, &r->work) != n)
fatal("convM2S format error");
DEBUG(DFD, "%F\n", &r->work);
(fcalls[r->work.type])(r);
}
}
void
reply(Fcall *r, Fcall *t, char *err)
{
uchar *data;
int n;
t->tag = r->tag;
t->fid = r->fid;
if(err != nil) {
t->type = Rerror;
t->ename = err;
}
else
t->type = r->type + 1;
DEBUG(DFD, "\t%F\n", t);
data = malloc(messagesize); /* not mallocz; no need to clear */
if(data == nil)
fatal(Enomem);
n = convS2M(t, data, messagesize);
if(write(0, data, n) != n){
/* not fatal, might have got a note due to flush */
fprint(2, "exportfs: short write in reply: %r\n");
}
free(data);
}
Fid *
getfid(int nr)
{
Fid *f;
for(f = fidhash(nr); f != nil; f = f->next)
if(f->nr == nr)
return f;
return nil;
}
int
freefid(int nr)
{
Fid *f, **l;
char buf[128];
l = &fidhash(nr);
for(f = *l; f != nil; f = f->next) {
if(f->nr == nr) {
if(f->mid) {
snprint(buf, sizeof(buf), "/mnt/exportfs/%d", f->mid);
unmount(0, buf);
psmap[f->mid] = 0;
}
if(f->f != nil) {
freefile(f->f);
f->f = nil;
}
if(f->dir != nil){
free(f->dir);
f->dir = nil;
}
*l = f->next;
f->next = fidfree;
fidfree = f;
return 1;
}
l = &f->next;
}
return 0;
}
Fid *
newfid(int nr)
{
Fid *new, **l;
int i;
l = &fidhash(nr);
for(new = *l; new != nil; new = new->next)
if(new->nr == nr)
return nil;
if(fidfree == nil) {
fidfree = emallocz(sizeof(Fid) * Fidchunk);
for(i = 0; i < Fidchunk-1; i++)
fidfree[i].next = &fidfree[i+1];
fidfree[Fidchunk-1].next = nil;
}
new = fidfree;
fidfree = new->next;
memset(new, 0, sizeof(Fid));
new->next = *l;
*l = new;
new->nr = nr;
new->fid = -1;
new->mid = 0;
return new;
}
static struct {
Lock;
Fsrpc *free;
/* statistics */
int nalloc;
int nfree;
} sbufalloc;
Fsrpc *
getsbuf(void)
{
Fsrpc *w;
lock(&sbufalloc);
w = sbufalloc.free;
if(w != nil){
sbufalloc.free = w->next;
w->next = nil;
sbufalloc.nfree--;
unlock(&sbufalloc);
} else {
sbufalloc.nalloc++;
unlock(&sbufalloc);
w = emallocz(sizeof(*w) + messagesize);
}
w->flushtag = NOTAG;
return w;
}
void
putsbuf(Fsrpc *w)
{
w->flushtag = NOTAG;
lock(&sbufalloc);
w->next = sbufalloc.free;
sbufalloc.free = w;
sbufalloc.nfree++;
unlock(&sbufalloc);
}
void
freefile(File *f)
{
File *parent, *child;
while(--f->ref == 0){
freecnt++;
DEBUG(DFD, "free %s\n", f->name);
/* delete from parent */
parent = f->parent;
if(parent->child == f)
parent->child = f->childlist;
else{
for(child = parent->child; child->childlist != f; child = child->childlist) {
if(child->childlist == nil)
fatal("bad child list");
}
child->childlist = f->childlist;
}
freeqid(f->qidt);
free(f->name);
free(f);
f = parent;
}
}
File *
file(File *parent, char *name)
{
Dir *dir;
char *path;
File *f;
DEBUG(DFD, "\tfile: 0x%p %s name %s\n", parent, parent->name, name);
path = makepath(parent, name);
if(patternfile != nil && excludefile(path)){
free(path);
return nil;
}
dir = dirstat(path);
free(path);
if(dir == nil)
return nil;
for(f = parent->child; f != nil; f = f->childlist)
if(strcmp(name, f->name) == 0)
break;
if(f == nil){
f = emallocz(sizeof(File));
f->name = estrdup(name);
f->parent = parent;
f->childlist = parent->child;
parent->child = f;
parent->ref++;
f->ref = 0;
filecnt++;
}
f->ref++;
f->qid.type = dir->qid.type;
f->qid.vers = dir->qid.vers;
f->qidt = uniqueqid(dir);
f->qid.path = f->qidt->uniqpath;
f->inval = 0;
free(dir);
return f;
}
void
initroot(void)
{
Dir *dir;
root = emallocz(sizeof(File));
root->name = estrdup(".");
dir = dirstat(root->name);
if(dir == nil)
fatal("root stat");
root->ref = 1;
root->qid.vers = dir->qid.vers;
root->qidt = uniqueqid(dir);
root->qid.path = root->qidt->uniqpath;
root->qid.type = QTDIR;
free(dir);
psmpt = emallocz(sizeof(File));
psmpt->name = estrdup("/");
dir = dirstat(psmpt->name);
if(dir == nil)
return;
psmpt->ref = 1;
psmpt->qid.vers = dir->qid.vers;
psmpt->qidt = uniqueqid(dir);
psmpt->qid.path = psmpt->qidt->uniqpath;
free(dir);
psmpt = file(psmpt, "mnt");
if(psmpt == nil)
return;
psmpt = file(psmpt, "exportfs");
}
char*
makepath(File *p, char *name)
{
int i, n;
char *c, *s, *path, *seg[256];
seg[0] = name;
n = strlen(name)+2;
for(i = 1; i < 256 && p; i++, p = p->parent){
seg[i] = p->name;
n += strlen(p->name)+1;
}
path = emallocz(n);
s = path;
while(i--) {
for(c = seg[i]; *c; c++)
*s++ = *c;
*s++ = '/';
}
while(s[-1] == '/')
s--;
*s = '\0';
return path;
}
int
qidhash(vlong path)
{
int h, n;
h = 0;
for(n=0; n<64; n+=Nqidbits){
h ^= path;
path >>= Nqidbits;
}
return h & (Nqidtab-1);
}
void
freeqid(Qidtab *q)
{
ulong h;
Qidtab *l;
if(--q->ref)
return;
qfreecnt++;
h = qidhash(q->path);
if(qidtab[h] == q)
qidtab[h] = q->next;
else{
for(l=qidtab[h]; l->next!=q; l=l->next)
if(l->next == nil)
fatal("bad qid list");
l->next = q->next;
}
free(q);
}
Qidtab*
qidlookup(Dir *d)
{
ulong h;
Qidtab *q;
h = qidhash(d->qid.path);
for(q=qidtab[h]; q!=nil; q=q->next)
if(q->type==d->type && q->dev==d->dev && q->path==d->qid.path)
return q;
return nil;
}
int
qidexists(vlong path)
{
int h;
Qidtab *q;
for(h=0; h<Nqidtab; h++)
for(q=qidtab[h]; q!=nil; q=q->next)
if(q->uniqpath == path)
return 1;
return 0;
}
Qidtab*
uniqueqid(Dir *d)
{
ulong h;
vlong path;
Qidtab *q;
q = qidlookup(d);
if(q != nil){
q->ref++;
return q;
}
path = d->qid.path;
while(qidexists(path)){
DEBUG(DFD, "collision on %s\n", d->name);
/* collision: find a new one */
ncollision++;
path &= QIDPATH;
++newqid;
if(newqid >= (1<<16)){
DEBUG(DFD, "collision wraparound\n");
newqid = 1;
}
path |= newqid<<48;
DEBUG(DFD, "assign qid %.16llux\n", path);
}
qidcnt++;
q = emallocz(sizeof(Qidtab));
q->ref = 1;
q->type = d->type;
q->dev = d->dev;
q->path = d->qid.path;
q->uniqpath = path;
h = qidhash(d->qid.path);
q->next = qidtab[h];
qidtab[h] = q;
return q;
}
void
fatal(char *s, ...)
{
char buf[ERRMAX];
va_list arg;
Proc *m;
if(s != nil) {
va_start(arg, s);
vsnprint(buf, ERRMAX, s, arg);
va_end(arg);
}
/* Clear away the slave children */
for(m = Proclist; m != nil; m = m->next)
postnote(PNPROC, m->pid, "kill");
if(s != nil) {
DEBUG(DFD, "%s\n", buf);
sysfatal("%s", buf); /* caution: buf could contain '%' */
} else
exits(nil);
}
void*
emallocz(uint n)
{
void *p;
p = mallocz(n, 1);
if(p == nil)
fatal(Enomem);
setmalloctag(p, getcallerpc(&n));
return p;
}
char*
estrdup(char *s)
{
char *t;
t = strdup(s);
if(t == nil)
fatal(Enomem);
setmalloctag(t, getcallerpc(&s));
return t;
}
void
filter(int fd, char *cmd, char *host)
{
char addr[128], buf[256], *s, *file, *argv[16];
int lfd, p[2], len, argc;
if(host == nil){
/* Get a free port and post it to the client. */
if (announce(anstring, addr) < 0)
fatal("filter: Cannot announce %s: %r", anstring);
snprint(buf, sizeof(buf), "%s/local", addr);
if ((lfd = open(buf, OREAD)) < 0)
fatal("filter: Cannot open %s: %r", buf);
if ((len = read(lfd, buf, sizeof buf - 1)) < 0)
fatal("filter: Cannot read %s: %r", buf);
close(lfd);
buf[len] = '\0';
if ((s = strchr(buf, '\n')) != nil)
len = s - buf;
if (write(fd, buf, len) != len)
fatal("filter: cannot write port; %r");
} else {
/* Read address string from connection */
if ((len = read(fd, buf, sizeof buf - 1)) < 0)
sysfatal("filter: cannot write port; %r");
buf[len] = '\0';
if ((s = strrchr(buf, '!')) == nil)
sysfatal("filter: illegally formatted port %s", buf);
strecpy(addr, addr+sizeof(addr), netmkaddr(host, "tcp", s+1));
strecpy(strrchr(addr, '!'), addr+sizeof(addr), s);
}
DEBUG(DFD, "filter: %s\n", addr);
snprint(buf, sizeof(buf), "%s", cmd);
argc = tokenize(buf, argv, nelem(argv)-3);
if (argc == 0)
sysfatal("filter: empty command");
if(host != nil)
argv[argc++] = "-c";
argv[argc++] = addr;
argv[argc] = nil;
file = argv[0];
if((s = strrchr(argv[0], '/')) != nil)
argv[0] = s+1;
if(pipe(p) < 0)
sysfatal("pipe: %r");
switch(rfork(RFNOWAIT|RFPROC|RFMEM|RFFDG|RFREND)) {
case -1:
fatal("filter: rfork; %r\n");
case 0:
close(fd);
if (dup(p[0], 1) < 0)
fatal("filter: Cannot dup to 1; %r");
if (dup(p[0], 0) < 0)
fatal("filter: Cannot dup to 0; %r");
close(p[0]);
close(p[1]);
exec(file, argv);
fatal("filter: exec; %r");
default:
dup(p[1], fd);
close(p[0]);
close(p[1]);
}
}
static void
mksecret(char *t, uchar *f)
{
sprint(t, "%2.2ux%2.2ux%2.2ux%2.2ux%2.2ux%2.2ux%2.2ux%2.2ux%2.2ux%2.2ux",
f[0], f[1], f[2], f[3], f[4], f[5], f[6], f[7], f[8], f[9]);
}