ref: 1a12079c7124c8ceb79a4644715d21bdf5328314
dir: /c9/c9.c/
/*
* This is 9p client and server implementation which aims to be
* correct, small and secure. It's the lowest level implementation.
* It doesn't have much comments, mostly because it doesn't make
* any sense to copy-paste protocol documentation, which
* you can read at http://man.cat-v.org/plan_9/5/, see 'intro'.
*/
#include <string.h>
#include <stdint.h>
#include "c9.h"
enum
{
Svver = 1<<0,
};
#define safestrlen(s) (s == NULL ? 0 : (uint32_t)strlen(s))
#define maxread(c) (c->msize-4-4-1-2)
#define maxwrite(c) maxread(c)
static void
w08(uint8_t **p, uint8_t x)
{
(*p)[0] = x;
*p += 1;
}
static void
w16(uint8_t **p, uint16_t x)
{
(*p)[0] = x;
(*p)[1] = x>>8;
*p += 2;
}
static void
w32(uint8_t **p, uint32_t x)
{
(*p)[0] = x;
(*p)[1] = x>>8;
(*p)[2] = x>>16;
(*p)[3] = x>>24;
*p += 4;
}
static void
w64(uint8_t **p, uint64_t x)
{
(*p)[0] = x;
(*p)[1] = x>>8;
(*p)[2] = x>>16;
(*p)[3] = x>>24;
(*p)[4] = x>>32;
(*p)[5] = x>>40;
(*p)[6] = x>>48;
(*p)[7] = x>>56;
*p += 8;
}
static void
wcs(uint8_t **p, const char *s, int len)
{
w16(p, len);
if(s != NULL){
memmove(*p, s, len);
*p += len;
}
}
static uint8_t
r08(uint8_t **p)
{
*p += 1;
return (*p)[-1];
}
static uint16_t
r16(uint8_t **p)
{
*p += 2;
return (uint16_t)(*p)[-2]<<0 | (uint16_t)(*p)[-1]<<8;
}
static uint32_t
r32(uint8_t **p)
{
return r16(p) | (uint32_t)r16(p)<<16;
}
static uint64_t
r64(uint8_t **p)
{
return r32(p) | (uint64_t)r32(p)<<32;
}
#ifndef C9_NO_CLIENT
static C9error
newtag(C9ctx *c, C9ttype type, C9tag *tag)
{
uint32_t i;
if(type == Tversion){
*tag = 0xffff;
return 0;
}
if(c->lowfreetag < C9maxtags){
uint32_t d = c->lowfreetag / C9tagsbits, m = c->lowfreetag % C9tagsbits;
if((c->tags[d] & 1<<m) != 0){
c->tags[d] &= ~(1<<m);
*tag = c->lowfreetag++;
return 0;
}
}
for(i = 0; i < (int)sizeof(c->tags)/sizeof(c->tags[0]); i++){
uint32_t x, j;
if((x = c->tags[i]) == 0)
continue;
for(j = 0; j < C9tagsbits; j++){
if((x & (1<<j)) != 0){
c->tags[i] &= ~(1<<j);
*tag = i*C9tagsbits + j;
c->lowfreetag = *tag + 1;
return 0;
}
}
}
c->error("newtag: no free tags");
return C9Etag;
}
static int
freetag(C9ctx *c, C9tag tag)
{
if(tag != 0xffff){
uint32_t d = tag / C9tagsbits, m = tag % C9tagsbits;
if(tag >= C9maxtags){
c->error("freetag: invalid tag");
return -1;
}
if((c->tags[d] & 1<<m) != 0){
c->error("freetag: double free");
return -1;
}
if(c->lowfreetag > tag)
c->lowfreetag = tag;
c->tags[d] |= 1<<m;
}
return 0;
}
static uint8_t *
T(C9ctx *c, uint32_t size, C9ttype type, C9tag *tag, C9error *err)
{
uint8_t *p = NULL;
if(size > c->msize-4-1-2){
c->error("T: invalid size");
*err = C9Esize;
}else if((*err = newtag(c, type, tag)) == 0){
size += 4+1+2;
if((p = c->begin(c, size)) == NULL){
c->error("T: no buffer");
freetag(c, *tag);
*err = C9Ebuf;
}else{
*err = 0;
w32(&p, size);
w08(&p, type);
w16(&p, *tag);
}
}
return p;
}
C9error
c9version(C9ctx *c, C9tag *tag, uint32_t msize)
{
uint8_t *b;
C9error err;
if(msize < C9minmsize){
c->error("c9version: msize too small");
return C9Einit;
}
memset(c->tags, 0xff, sizeof(c->tags));
memset(c->flush, 0xff, sizeof(c->flush));
c->lowfreetag = 0;
c->msize = msize;
if((b = T(c, 4+2+6, Tversion, tag, &err)) != NULL){
w32(&b, msize);
wcs(&b, "9P2000", 6);
err = c->end(c);
}
return err;
}
C9error
c9auth(C9ctx *c, C9tag *tag, C9fid afid, const char *uname, const char *aname)
{
uint8_t *b;
uint32_t ulen = safestrlen(uname), alen = safestrlen(aname);
C9error err;
if(ulen > C9maxstr || alen > C9maxstr){
c->error("c9auth: string too long");
return C9Estr;
}
if((b = T(c, 4+2+ulen+2+alen, Tauth, tag, &err)) != NULL){
w32(&b, afid);
wcs(&b, uname, ulen);
wcs(&b, aname, alen);
err = c->end(c);
}
return err;
}
C9error
c9flush(C9ctx *c, C9tag *tag, C9tag oldtag)
{
uint8_t *b;
C9error err;
int i;
for(i = 0; i < C9maxflush && c->flush[i] != (uint32_t)~0; i++);
if(i == C9maxflush){
c->error("c9flush: no free flush slots");
return C9Eflush;
}
if((b = T(c, 2, Tflush, tag, &err)) != NULL){
w16(&b, oldtag);
err = c->end(c);
if(err == 0)
c->flush[i] = (uint32_t)oldtag<<16 | *tag;
}
return err;
}
C9error
c9attach(C9ctx *c, C9tag *tag, C9fid fid, C9fid afid, const char *uname, const char *aname)
{
uint32_t ulen = safestrlen(uname), alen = safestrlen(aname);
uint8_t *b;
C9error err;
if(ulen > C9maxstr || alen > C9maxstr){
c->error("c9attach: string too long");
return C9Estr;
}
if((b = T(c, 4+4+2+ulen+2+alen, Tattach, tag, &err)) != NULL){
w32(&b, fid);
w32(&b, afid);
wcs(&b, uname, ulen);
wcs(&b, aname, alen);
err = c->end(c);
}
return err;
}
C9error
c9walk(C9ctx *c, C9tag *tag, C9fid fid, C9fid newfid, const char *path[])
{
uint32_t i, j, sz;
uint32_t len[C9maxpathel];
uint8_t *b;
C9error err;
for(sz = i = 0; i < (int)sizeof(len)/sizeof(len[0]) && path[i] != NULL; i++){
len[i] = safestrlen(path[i]);
if(len[i] == 0 || len[i] > C9maxstr){
c->error("c9walk: path element too long");
return C9Epath;
}
sz += 2 + len[i];
}
if(path[i] != NULL || i == 0){
c->error("c9walk: invalid elements !(0 < %d <= %d)", i, C9maxpathel);
return C9Epath;
}
if((b = T(c, 4+4+2+sz, Twalk, tag, &err)) != NULL){
w32(&b, fid);
w32(&b, newfid);
w16(&b, i);
for(j = 0; j < i; j++)
wcs(&b, path[j], len[j]);
err = c->end(c);
}
return err;
}
C9error
c9open(C9ctx *c, C9tag *tag, C9fid fid, C9mode mode)
{
uint8_t *b;
C9error err;
if((b = T(c, 4+1, Topen, tag, &err)) != NULL){
w32(&b, fid);
w08(&b, mode);
err = c->end(c);
}
return err;
}
C9error
c9create(C9ctx *c, C9tag *tag, C9fid fid, const char *name, uint32_t perm, C9mode mode)
{
uint32_t nlen = strlen(name);
uint8_t *b;
C9error err;
if(nlen == 0 || nlen > C9maxstr){
c->error("c9create: invalid name");
return C9Epath;
}
if((b = T(c, 4+2+nlen+4+1, Tcreate, tag, &err)) != NULL){
w32(&b, fid);
wcs(&b, name, nlen);
w32(&b, perm);
w08(&b, mode);
err = c->end(c);
}
return err;
}
C9error
c9read(C9ctx *c, C9tag *tag, C9fid fid, uint64_t offset, uint32_t count)
{
uint8_t *b;
C9error err;
if((b = T(c, 4+8+4, Tread, tag, &err)) != NULL){
w32(&b, fid);
w64(&b, offset);
w32(&b, count);
err = c->end(c);
}
return err;
}
C9error
c9write(C9ctx *c, C9tag *tag, C9fid fid, uint64_t offset, const void *in, uint32_t count)
{
uint8_t *b;
C9error err;
if((b = T(c, 4+8+4+count, Twrite, tag, &err)) != NULL){
w32(&b, fid);
w64(&b, offset);
w32(&b, count);
memmove(b, in, count);
err = c->end(c);
}
return err;
}
C9error
c9wrstr(C9ctx *c, C9tag *tag, C9fid fid, const char *s)
{
return c9write(c, tag, fid, 0, s, strlen(s));
}
C9error
c9clunk(C9ctx *c, C9tag *tag, C9fid fid)
{
uint8_t *b;
C9error err;
if((b = T(c, 4, Tclunk, tag, &err)) != NULL){
w32(&b, fid);
err = c->end(c);
}
return err;
}
C9error
c9remove(C9ctx *c, C9tag *tag, C9fid fid)
{
uint8_t *b;
C9error err;
if((b = T(c, 4, Tremove, tag, &err)) != NULL){
w32(&b, fid);
err = c->end(c);
}
return err;
}
C9error
c9stat(C9ctx *c, C9tag *tag, C9fid fid)
{
uint8_t *b;
C9error err;
if((b = T(c, 4, Tstat, tag, &err)) != NULL){
w32(&b, fid);
err = c->end(c);
}
return err;
}
C9error
c9wstat(C9ctx *c, C9tag *tag, C9fid fid, const C9stat *s)
{
uint32_t nlen = safestrlen(s->name), ulen = safestrlen(s->uid), glen = safestrlen(s->gid);
uint32_t unusedsz = 2+4+13, statsz = unusedsz+4+4+4+8+2+nlen+2+ulen+2+glen+2;
uint8_t *b;
C9error err;
if(nlen == 0 || nlen > C9maxstr){
c->error("c9wstat: invalid name");
return C9Epath;
}
if(ulen > C9maxstr || glen > C9maxstr){
c->error("c9wstat: string too long");
return C9Estr;
}
if((b = T(c, 4+2+2+statsz, Twstat, tag, &err)) != NULL){
w32(&b, fid);
w16(&b, statsz+2);
w16(&b, statsz);
memset(b, 0xff, unusedsz); /* leave type(2), dev(4) and qid(13) unchanged */
b += unusedsz;
w32(&b, s->mode);
w32(&b, s->atime);
w32(&b, s->mtime);
w64(&b, s->size);
wcs(&b, s->name, nlen);
wcs(&b, s->uid, ulen);
wcs(&b, s->gid, glen);
wcs(&b, NULL, 0); /* muid unchanged */
err = c->end(c);
}
return err;
}
C9error
c9proc(C9ctx *c)
{
uint32_t i, sz, cnt, msize;
uint8_t *b;
int err;
C9r r;
err = -1;
if((b = c->read(c, 4, &err)) == NULL){
if(err != 0)
c->error("c9proc: short read");
return err == 0 ? 0 : C9Epkt;
}
sz = r32(&b);
if(sz < 7 || sz > c->msize){
c->error("c9proc: invalid packet size !(7 <= %u <= %u)", sz, c->msize);
return C9Epkt;
}
sz -= 4;
err = -1;
if((b = c->read(c, sz, &err)) == NULL){
if(err != 0)
c->error("c9proc: short read");
return err == 0 ? 0 : C9Epkt;
}
r.type = r08(&b);
r.tag = r16(&b);
if(r.type != Rversion){
if(r.tag >= C9maxtags){
c->error("c9proc: invalid tag 0x%x", r.tag);
return C9Epkt;
}
if(freetag(c, r.tag) != 0)
return C9Etag;
}
sz -= 3;
r.numqid = 0;
switch(r.type){
case Rread:
if(sz < 4 || (cnt = r32(&b)) > sz-4)
goto error;
r.read.data = b;
r.read.size = cnt;
c->r(c, &r);
break;
case Rwrite:
if(sz < 4 || (cnt = r32(&b)) > c->msize)
goto error;
r.write.size = cnt;
c->r(c, &r);
break;
case Rwalk:
if(sz < 2+13 || (cnt = r16(&b))*13 > sz-2)
goto error;
if(cnt > C9maxpathel){
c->error("c9proc: Rwalk !(%d <= %d)", cnt, C9maxpathel);
return C9Epath;
}
for(i = 0; i < cnt; i++){
r.qid[i].type = r08(&b);
r.qid[i].version = r32(&b);
r.qid[i].path = r64(&b);
}
r.numqid = cnt;
c->r(c, &r);
break;
case Rstat:
b += 2; sz -= 2;
if((err = c9parsedir(c, &r.stat, &b, &sz)) != 0){
c->error("c9proc");
return err;
}
r.numqid = 1;
c->r(c, &r);
break;
case Rflush:
for(i = 0; i < C9maxflush; i++){
if((c->flush[i] & 0xffff) == r.tag){
freetag(c, c->flush[i]>>16);
c->flush[i] = 0xffffffff;
break;
}
}
/* fallthrough */
case Rclunk:
case Rremove:
case Rwstat:
c->r(c, &r);
break;
case Ropen:
case Rcreate:
if(sz < 17)
goto error;
r.qid[0].type = r08(&b);
r.qid[0].version = r32(&b);
r.qid[0].path = r64(&b);
r.iounit = r32(&b);
r.numqid = 1;
c->r(c, &r);
break;
case Rerror:
if(sz < 2 || (cnt = r16(&b)) > sz-2)
goto error;
r.error = memmove(b-1, b, cnt);
r.error[cnt] = 0;
c->r(c, &r);
break;
case Rauth:
case Rattach:
if(sz < 13)
goto error;
r.qid[0].type = r08(&b);
r.qid[0].version = r32(&b);
r.qid[0].path = r64(&b);
r.numqid = 1;
c->r(c, &r);
break;
case Rversion:
if(sz < 4+2 || (msize = r32(&b)) < C9minmsize || (cnt = r16(&b)) > sz-4-2)
goto error;
if(cnt < 6 || memcmp(b, "9P2000", 6) != 0){
c->error("invalid version");
return C9Ever;
}
if(msize < c->msize)
c->msize = msize;
c->r(c, &r);
break;
default:
goto error;
}
return 0;
error:
c->error("c9proc: invalid packet (type=%d)", r.type);
return C9Epkt;
}
#endif /* C9_NO_CLIENT */
C9error
c9parsedir(C9ctx *c, C9stat *stat, uint8_t **t, uint32_t *size)
{
uint8_t *b;
uint32_t cnt, sz;
if(*size < 49 || (sz = r16(t)) < 47 || *size < 2+sz)
goto error;
*size -= 2+sz;
*t += 6; /* skip type(2) and dev(4) */
stat->qid.type = r08(t);
stat->qid.version = r32(t);
stat->qid.path = r64(t);
stat->mode = r32(t);
stat->atime = r32(t);
stat->mtime = r32(t);
stat->size = r64(t);
sz -= 39;
if((cnt = r16(t)) > sz-2)
goto error;
stat->name = (char*)*t; b = *t = *t+cnt; sz -= 2+cnt;
if(sz < 2 || (cnt = r16(t)) > sz-2)
goto error;
stat->uid = (char*)*t; *b = 0; b = *t = *t+cnt; sz -= 2+cnt;
if(sz < 2 || (cnt = r16(t)) > sz-2)
goto error;
stat->gid = (char*)*t; *b = 0; b = *t = *t+cnt; sz -= 2+cnt;
if(sz < 2 || (cnt = r16(t)) > sz-2)
goto error;
stat->muid = memmove(*t-1, *t, cnt); *b = stat->muid[cnt] = 0; *t = *t+cnt; sz -= 2+cnt;
*t += sz;
return 0;
error:
c->error("c9parsedir: invalid size");
return C9Epkt;
}
#ifndef C9_NO_SERVER
static uint8_t *
R(C9ctx *c, uint32_t size, C9rtype type, C9tag tag, C9error *err)
{
uint8_t *p = NULL;
if(size > c->msize-4-1-2){
c->error("R: invalid size");
*err = C9Esize;
}else{
size += 4+1+2;
if((p = c->begin(c, size)) == NULL){
c->error("R: no buffer");
*err = C9Ebuf;
}else{
*err = 0;
w32(&p, size);
w08(&p, type);
w16(&p, tag);
}
}
return p;
}
C9error
s9version(C9ctx *c)
{
uint8_t *b;
C9error err;
if((b = R(c, 4+2+6, Rversion, 0xffff, &err)) != NULL){
w32(&b, c->msize);
wcs(&b, "9P2000", 6);
err = c->end(c);
};
return err;
}
C9error
s9auth(C9ctx *c, C9tag tag, const C9qid *aqid)
{
uint8_t *b;
C9error err;
if((b = R(c, 13, Rauth, tag, &err)) != NULL){
w08(&b, aqid->type);
w32(&b, aqid->version);
w64(&b, aqid->path);
err = c->end(c);
}
return err;
}
C9error
s9error(C9ctx *c, C9tag tag, const char *ename)
{
uint32_t len = safestrlen(ename);
uint8_t *b;
C9error err;
if(len > C9maxstr){
c->error("s9error: invalid ename");
return C9Estr;
}
if((b = R(c, 2+len, Rerror, tag, &err)) != NULL){
wcs(&b, ename, len);
err = c->end(c);
}
return err;
}
C9error
s9attach(C9ctx *c, C9tag tag, const C9qid *qid)
{
uint8_t *b;
C9error err;
if((b = R(c, 13, Rattach, tag, &err)) != NULL){
w08(&b, qid->type);
w32(&b, qid->version);
w64(&b, qid->path);
err = c->end(c);
}
return err;
}
C9error
s9flush(C9ctx *c, C9tag tag)
{
uint8_t *b;
C9error err;
if((b = R(c, 0, Rflush, tag, &err)) != NULL)
err = c->end(c);
return err;
}
C9error
s9walk(C9ctx *c, C9tag tag, C9qid *qids[])
{
uint32_t i, n;
uint8_t *b;
C9error err;
for(n = 0; n < C9maxpathel && qids[n] != NULL; n++);
if(n > C9maxpathel){
c->error("s9walk: invalid elements !(0 <= %d <= %d)", n, C9maxpathel);
return C9Epath;
}
if((b = R(c, 2+n*13, Rwalk, tag, &err)) != NULL){
w16(&b, n);
for(i = 0; i < n; i++){
w08(&b, qids[i]->type);
w32(&b, qids[i]->version);
w64(&b, qids[i]->path);
}
err = c->end(c);
}
return err;
}
C9error
s9open(C9ctx *c, C9tag tag, const C9qid *qid, uint32_t iounit)
{
uint8_t *b;
C9error err;
if((b = R(c, 13+4, Ropen, tag, &err)) != NULL){
w08(&b, qid->type);
w32(&b, qid->version);
w64(&b, qid->path);
w32(&b, iounit);
err = c->end(c);
}
return err;
}
C9error
s9create(C9ctx *c, C9tag tag, const C9qid *qid, uint32_t iounit)
{
uint8_t *b;
C9error err;
if((b = R(c, 13+4, Rcreate, tag, &err)) != NULL){
w08(&b, qid->type);
w32(&b, qid->version);
w64(&b, qid->path);
w32(&b, iounit);
err = c->end(c);
}
return err;
}
C9error
s9read(C9ctx *c, C9tag tag, const void *data, uint32_t size)
{
uint8_t *b;
C9error err;
if((b = R(c, 4+size, Rread, tag, &err)) != NULL){
w32(&b, size);
memmove(b, data, size);
err = c->end(c);
}
return err;
}
C9error
s9write(C9ctx *c, C9tag tag, uint32_t size)
{
uint8_t *b;
C9error err;
if((b = R(c, 4, Rwrite, tag, &err)) != NULL){
w32(&b, size);
err = c->end(c);
}
return err;
}
C9error
s9readdir(C9ctx *c, C9tag tag, C9stat *st[], int *num, uint64_t *offset, uint32_t size)
{
uint8_t *b;
const C9stat *s;
uint32_t nlen, ulen, glen, mulen, m, n;
C9error err;
int i;
if(size > c->msize-4-1-2)
size = c->msize-4-1-2;
m = 0;
for(i = 0; i < *num; i++){
s = st[i];
nlen = safestrlen(s->name);
ulen = safestrlen(s->uid);
glen = safestrlen(s->gid);
mulen = safestrlen(s->muid);
if(nlen == 0 || nlen > C9maxstr){
c->error("s9readdir: invalid name");
return C9Epath;
}
if(ulen > C9maxstr || glen > C9maxstr || mulen > C9maxstr){
c->error("s9readdir: string too long");
return C9Estr;
}
n = 2 + 2+4+13+4+4+4+8+2+nlen+2+ulen+2+glen+2+mulen;
if(4+m+n > size)
break;
m += n;
}
if((b = R(c, 4+m, Rread, tag, &err)) != NULL){
*num = i;
w32(&b, m);
for(i = 0; i < *num; i++){
s = st[i];
nlen = safestrlen(s->name);
ulen = safestrlen(s->uid);
glen = safestrlen(s->gid);
mulen = safestrlen(s->muid);
w16(&b, 2+4+13+4+4+4+8+2+nlen+2+ulen+2+glen+2+mulen);
w16(&b, 0xffff); /* type */
w32(&b, 0xffffffff); /* dev */
w08(&b, s->qid.type);
w32(&b, s->qid.version);
w64(&b, s->qid.path);
w32(&b, s->mode);
w32(&b, s->atime);
w32(&b, s->mtime);
w64(&b, s->size);
wcs(&b, s->name, nlen);
wcs(&b, s->uid, ulen);
wcs(&b, s->gid, glen);
wcs(&b, s->muid, mulen);
}
err = c->end(c);
if(err == 0)
*offset += m;
}
return err;
}
C9error
s9clunk(C9ctx *c, C9tag tag)
{
uint8_t *b;
C9error err;
if((b = R(c, 0, Rclunk, tag, &err)) != NULL)
err = c->end(c);
return err;
}
C9error
s9remove(C9ctx *c, C9tag tag)
{
uint8_t *b;
C9error err;
if((b = R(c, 0, Rremove, tag, &err)) != NULL)
err = c->end(c);
return err;
}
C9error
s9stat(C9ctx *c, C9tag tag, const C9stat *s)
{
uint32_t nlen = safestrlen(s->name), ulen = safestrlen(s->uid);
uint32_t glen = safestrlen(s->gid), mulen = safestrlen(s->name);
uint32_t statsz = 2+4+13+4+4+4+8+2+nlen+2+ulen+2+glen+2+mulen;
uint8_t *b;
C9error err;
if(nlen == 0 || nlen > C9maxstr){
c->error("s9stat: invalid name");
return C9Epath;
}
if(ulen > C9maxstr || glen > C9maxstr || mulen > C9maxstr){
c->error("s9stat: string too long");
return C9Estr;
}
if((b = R(c, 2+2+statsz, Rstat, tag, &err)) != NULL){
w16(&b, statsz+2);
w16(&b, statsz);
w16(&b, 0xffff); /* type */
w32(&b, 0xffffffff); /* dev */
w08(&b, s->qid.type);
w32(&b, s->qid.version);
w64(&b, s->qid.path);
w32(&b, s->mode);
w32(&b, s->atime);
w32(&b, s->mtime);
w64(&b, s->size);
wcs(&b, s->name, nlen);
wcs(&b, s->uid, ulen);
wcs(&b, s->gid, glen);
wcs(&b, s->muid, mulen);
err = c->end(c);
}
return err;
}
C9error
s9wstat(C9ctx *c, C9tag tag)
{
uint8_t *b;
C9error err;
if((b = R(c, 0, Rwstat, tag, &err)) != NULL)
err = c->end(c);
return err;
}
C9error
s9proc(C9ctx *c)
{
uint32_t i, sz, cnt, n, msize;
int readerr;
uint8_t *b;
C9error err;
C9t t;
readerr = -1;
if((b = c->read(c, 4, &readerr)) == NULL){
if(readerr != 0)
c->error("s9proc: short read");
return readerr == 0 ? 0 : C9Epkt;
}
sz = r32(&b);
if(sz < 7 || sz > c->msize){
c->error("s9proc: invalid packet size !(7 <= %u <= %u)", sz, c->msize);
return C9Epkt;
}
sz -= 4;
readerr = -1;
if((b = c->read(c, sz, &readerr)) == NULL){
if(readerr != 0)
c->error("s9proc: short read");
return readerr == 0 ? 0 : C9Epkt;
}
t.type = r08(&b);
t.tag = r16(&b);
sz -= 3;
if((c->svflags & Svver) == 0 && t.type != Tversion){
c->error("s9proc: expected Tversion, got %d", t.type);
return C9Epkt;
}
switch(t.type){
case Tread:
if(sz < 4+8+4)
goto error;
t.fid = r32(&b);
t.read.offset = r64(&b);
t.read.size = r32(&b);
if(t.read.size > maxread(c))
t.read.size = maxread(c);
c->t(c, &t);
break;
case Twrite:
if(sz < 4+8+4)
goto error;
t.fid = r32(&b);
t.write.offset = r64(&b);
if((t.write.size = r32(&b)) < sz-4-8-4)
goto error;
if(t.write.size > maxwrite(c))
t.write.size = maxwrite(c);
t.write.data = b;
c->t(c, &t);
break;
case Tclunk:
case Tstat:
case Tremove:
if(sz < 4)
goto error;
t.fid = r32(&b);
c->t(c, &t);
break;
case Twalk:
if(sz < 4+4+2)
goto error;
t.fid = r32(&b);
t.walk.newfid = r32(&b);
if((n = r16(&b)) > 16){
c->error("s9proc: Twalk !(%d <= 16)", n);
return C9Epath;
}
sz -= 4+4+2;
if(n > 0){
for(i = 0; i < n; i++){
if(sz < 2 || (cnt = r16(&b)) > sz-2)
goto error;
if(cnt < 1){
c->error("s9proc: Twalk invalid element [%d]", i);
return C9Epath;
}
b[-2] = 0;
t.walk.wname[i] = (char*)b;
b += cnt;
sz -= 2 + cnt;
}
memmove(t.walk.wname[i-1]-1, t.walk.wname[i-1], (char*)b - t.walk.wname[i-1]);
t.walk.wname[i-1]--;
b[-1] = 0;
}else
i = 0;
t.walk.wname[i] = NULL;
c->t(c, &t);
break;
case Topen:
if(sz < 4+1)
goto error;
t.fid = r32(&b);
t.open.mode = r08(&b);
c->t(c, &t);
break;
case Twstat:
if(sz < 4+2)
goto error;
t.fid = r32(&b);
if((cnt = r16(&b)) > sz-4)
goto error;
if((err = c9parsedir(c, &t.wstat, &b, &cnt)) != 0){
c->error("s9proc");
return err;
}
c->t(c, &t);
break;
case Tcreate:
if(sz < 4+2+4+1)
goto error;
t.fid = r32(&b);
if((cnt = r16(&b)) < 1 || cnt > sz-4-2-4-1)
goto error;
t.create.name = (char*)b;
b += cnt;
t.create.perm = r32(&b);
t.create.mode = r08(&b);
t.create.name[cnt] = 0;
c->t(c, &t);
break;
case Tflush:
if(sz < 2)
goto error;
t.flush.oldtag = r16(&b);
c->t(c, &t);
break;
case Tversion:
if(sz < 4+2 || (msize = r32(&b)) < C9minmsize || (cnt = r16(&b)) > sz-4-2)
goto error;
if(cnt < 6 || memcmp(b, "9P2000", 6) != 0){
if((b = R(c, 4+2+7, Rversion, 0xffff, &err)) != NULL){
w32(&b, 0);
wcs(&b, "unknown", 7);
err = c->end(c);
c->error("s9proc: invalid version");
}
return C9Ever;
}
if(msize < c->msize)
c->msize = msize;
c->svflags |= Svver;
c->t(c, &t);
break;
case Tattach:
if(sz < 4+4+2+2)
goto error;
t.fid = r32(&b);
t.attach.afid = r32(&b);
cnt = r16(&b);
sz -= 4+4+2;
if(cnt+2 > sz)
goto error;
t.attach.uname = (char*)b;
b += cnt;
cnt = r16(&b);
b[-2] = 0;
sz -= cnt+2;
if(cnt > sz)
goto error;
memmove(b-1, b, cnt);
t.attach.aname = (char*)b-1;
t.attach.aname[cnt] = 0;
c->t(c, &t);
break;
case Tauth:
if(sz < 4+2+2)
goto error;
t.auth.afid = r32(&b);
cnt = r16(&b);
sz -= 4+2;
if(cnt+2 > sz)
goto error;
t.auth.uname = (char*)b;
b += cnt;
cnt = r16(&b);
b[-2] = 0;
sz -= cnt+2;
if(cnt > sz)
goto error;
memmove(b-1, b, cnt);
t.auth.aname = (char*)b-1;
t.auth.aname[cnt] = 0;
c->t(c, &t);
break;
default:
goto error;
}
return 0;
error:
c->error("s9proc: invalid packet (type=%d)", t.type);
return C9Epkt;
}
#endif /* C9_NO_SERVER */