ref: fb7dd4b3a868cb8987049c95bb32e6425a73c8b9
dir: /emu/port/styx.c/
#include "dat.h"
#include "fns.h"
#include "error.h"
static
uchar*
gstring(uchar *p, uchar *ep, char **s)
{
uint n;
if(p+BIT16SZ > ep)
return nil;
n = GBIT16(p);
p += BIT16SZ - 1;
if(p+n+1 > ep)
return nil;
/* move it down, on top of count, to make room for '\0' */
memmove(p, p + 1, n);
p[n] = '\0';
*s = (char*)p;
p += n+1;
return p;
}
static
uchar*
gqid(uchar *p, uchar *ep, Qid *q)
{
if(p+QIDSZ > ep)
return nil;
q->type = GBIT8(p);
p += BIT8SZ;
q->vers = GBIT32(p);
p += BIT32SZ;
q->path = GBIT64(p);
p += BIT64SZ;
return p;
}
/*
* no syntactic checks.
* three causes for error:
* 1. message size field is incorrect
* 2. input buffer too short for its own data (counts too long, etc.)
* 3. too many names or qids
* gqid() and gstring() return nil if they would reach beyond buffer.
* main switch statement checks range and also can fall through
* to test at end of routine.
*/
uint
convM2S(uchar *ap, uint nap, Fcall *f)
{
uchar *p, *ep;
uint i, size;
p = ap;
ep = p + nap;
if(p+BIT32SZ+BIT8SZ+BIT16SZ > ep)
return 0;
size = GBIT32(p);
p += BIT32SZ;
if(size < BIT32SZ+BIT8SZ+BIT16SZ)
return 0;
f->type = GBIT8(p);
p += BIT8SZ;
f->tag = GBIT16(p);
p += BIT16SZ;
switch(f->type)
{
default:
return 0;
case Tversion:
if(p+BIT32SZ > ep)
return 0;
f->msize = GBIT32(p);
p += BIT32SZ;
p = gstring(p, ep, &f->version);
break;
case Tflush:
if(p+BIT16SZ > ep)
return 0;
f->oldtag = GBIT16(p);
p += BIT16SZ;
break;
case Tauth:
if(p+BIT32SZ > ep)
return 0;
f->afid = GBIT32(p);
p += BIT32SZ;
p = gstring(p, ep, &f->uname);
if(p == nil)
break;
p = gstring(p, ep, &f->aname);
if(p == nil)
break;
break;
case Tattach:
if(p+BIT32SZ > ep)
return 0;
f->fid = GBIT32(p);
p += BIT32SZ;
if(p+BIT32SZ > ep)
return 0;
f->afid = GBIT32(p);
p += BIT32SZ;
p = gstring(p, ep, &f->uname);
if(p == nil)
break;
p = gstring(p, ep, &f->aname);
if(p == nil)
break;
break;
case Twalk:
if(p+BIT32SZ+BIT32SZ+BIT16SZ > ep)
return 0;
f->fid = GBIT32(p);
p += BIT32SZ;
f->newfid = GBIT32(p);
p += BIT32SZ;
f->nwname = GBIT16(p);
p += BIT16SZ;
if(f->nwname > MAXWELEM)
return 0;
for(i=0; i<f->nwname; i++){
p = gstring(p, ep, &f->wname[i]);
if(p == nil)
break;
}
break;
case Topen:
if(p+BIT32SZ+BIT8SZ > ep)
return 0;
f->fid = GBIT32(p);
p += BIT32SZ;
f->mode = GBIT8(p);
p += BIT8SZ;
break;
case Tcreate:
if(p+BIT32SZ > ep)
return 0;
f->fid = GBIT32(p);
p += BIT32SZ;
p = gstring(p, ep, &f->name);
if(p == nil)
break;
if(p+BIT32SZ+BIT8SZ > ep)
return 0;
f->perm = GBIT32(p);
p += BIT32SZ;
f->mode = GBIT8(p);
p += BIT8SZ;
break;
case Tread:
if(p+BIT32SZ+BIT64SZ+BIT32SZ > ep)
return 0;
f->fid = GBIT32(p);
p += BIT32SZ;
f->offset = GBIT64(p);
p += BIT64SZ;
f->count = GBIT32(p);
p += BIT32SZ;
break;
case Twrite:
if(p+BIT32SZ+BIT64SZ+BIT32SZ > ep)
return 0;
f->fid = GBIT32(p);
p += BIT32SZ;
f->offset = GBIT64(p);
p += BIT64SZ;
f->count = GBIT32(p);
p += BIT32SZ;
if(p+f->count > ep)
return 0;
f->data = (char*)p;
p += f->count;
break;
case Tclunk:
case Tremove:
if(p+BIT32SZ > ep)
return 0;
f->fid = GBIT32(p);
p += BIT32SZ;
break;
case Tstat:
if(p+BIT32SZ > ep)
return 0;
f->fid = GBIT32(p);
p += BIT32SZ;
break;
case Twstat:
if(p+BIT32SZ+BIT16SZ > ep)
return 0;
f->fid = GBIT32(p);
p += BIT32SZ;
f->nstat = GBIT16(p);
p += BIT16SZ;
if(p+f->nstat > ep)
return 0;
f->stat = p;
p += f->nstat;
break;
/*
*/
case Rversion:
if(p+BIT32SZ > ep)
return 0;
f->msize = GBIT32(p);
p += BIT32SZ;
p = gstring(p, ep, &f->version);
break;
case Rerror:
p = gstring(p, ep, &f->ename);
break;
case Rflush:
break;
case Rauth:
p = gqid(p, ep, &f->aqid);
if(p == nil)
break;
break;
case Rattach:
p = gqid(p, ep, &f->qid);
if(p == nil)
break;
break;
case Rwalk:
if(p+BIT16SZ > ep)
return 0;
f->nwqid = GBIT16(p);
p += BIT16SZ;
if(f->nwqid > MAXWELEM)
return 0;
for(i=0; i<f->nwqid; i++){
p = gqid(p, ep, &f->wqid[i]);
if(p == nil)
break;
}
break;
case Ropen:
case Rcreate:
p = gqid(p, ep, &f->qid);
if(p == nil)
break;
if(p+BIT32SZ > ep)
return 0;
f->iounit = GBIT32(p);
p += BIT32SZ;
break;
case Rread:
if(p+BIT32SZ > ep)
return 0;
f->count = GBIT32(p);
p += BIT32SZ;
if(p+f->count > ep)
return 0;
f->data = (char*)p;
p += f->count;
break;
case Rwrite:
if(p+BIT32SZ > ep)
return 0;
f->count = GBIT32(p);
p += BIT32SZ;
break;
case Rclunk:
case Rremove:
break;
case Rstat:
if(p+BIT16SZ > ep)
return 0;
f->nstat = GBIT16(p);
p += BIT16SZ;
if(p+f->nstat > ep)
return 0;
f->stat = p;
p += f->nstat;
break;
case Rwstat:
break;
}
if(p==nil || p>ep)
return 0;
if(ap+size == p)
return size;
return 0;
}
static
uchar*
pstring(uchar *p, char *s)
{
uint n;
if(s == nil){
PBIT16(p, 0);
p += BIT16SZ;
return p;
}
n = strlen(s);
PBIT16(p, n);
p += BIT16SZ;
memmove(p, s, n);
p += n;
return p;
}
static
uchar*
pqid(uchar *p, Qid *q)
{
PBIT8(p, q->type);
p += BIT8SZ;
PBIT32(p, q->vers);
p += BIT32SZ;
PBIT64(p, q->path);
p += BIT64SZ;
return p;
}
static
uint
stringsz(char *s)
{
if(s == nil)
return BIT16SZ;
return BIT16SZ+strlen(s);
}
uint
sizeS2M(Fcall *f)
{
uint n;
int i;
n = 0;
n += BIT32SZ; /* size */
n += BIT8SZ; /* type */
n += BIT16SZ; /* tag */
switch(f->type)
{
default:
return 0;
case Tversion:
n += BIT32SZ;
n += stringsz(f->version);
break;
case Tflush:
n += BIT16SZ;
break;
case Tauth:
n += BIT32SZ;
n += stringsz(f->uname);
n += stringsz(f->aname);
break;
case Tattach:
n += BIT32SZ;
n += BIT32SZ;
n += stringsz(f->uname);
n += stringsz(f->aname);
break;
case Twalk:
n += BIT32SZ;
n += BIT32SZ;
n += BIT16SZ;
for(i=0; i<f->nwname; i++)
n += stringsz(f->wname[i]);
break;
case Topen:
n += BIT32SZ;
n += BIT8SZ;
break;
case Tcreate:
n += BIT32SZ;
n += stringsz(f->name);
n += BIT32SZ;
n += BIT8SZ;
break;
case Tread:
n += BIT32SZ;
n += BIT64SZ;
n += BIT32SZ;
break;
case Twrite:
n += BIT32SZ;
n += BIT64SZ;
n += BIT32SZ;
n += f->count;
break;
case Tclunk:
case Tremove:
n += BIT32SZ;
break;
case Tstat:
n += BIT32SZ;
break;
case Twstat:
n += BIT32SZ;
n += BIT16SZ;
n += f->nstat;
break;
/*
*/
case Rversion:
n += BIT32SZ;
n += stringsz(f->version);
break;
case Rerror:
n += stringsz(f->ename);
break;
case Rflush:
break;
case Rauth:
n += QIDSZ;
break;
case Rattach:
n += QIDSZ;
break;
case Rwalk:
n += BIT16SZ;
n += f->nwqid*QIDSZ;
break;
case Ropen:
case Rcreate:
n += QIDSZ;
n += BIT32SZ;
break;
case Rread:
n += BIT32SZ;
n += f->count;
break;
case Rwrite:
n += BIT32SZ;
break;
case Rclunk:
break;
case Rremove:
break;
case Rstat:
n += BIT16SZ;
n += f->nstat;
break;
case Rwstat:
break;
}
return n;
}
uint
convS2M(Fcall *f, uchar *ap, uint nap)
{
uchar *p;
uint i, size;
size = sizeS2M(f);
if(size == 0)
return 0;
if(size > nap)
return 0;
p = (uchar*)ap;
PBIT32(p, size);
p += BIT32SZ;
PBIT8(p, f->type);
p += BIT8SZ;
PBIT16(p, f->tag);
p += BIT16SZ;
switch(f->type)
{
default:
return 0;
case Tversion:
PBIT32(p, f->msize);
p += BIT32SZ;
p = pstring(p, f->version);
break;
case Tflush:
PBIT16(p, f->oldtag);
p += BIT16SZ;
break;
case Tauth:
PBIT32(p, f->afid);
p += BIT32SZ;
p = pstring(p, f->uname);
p = pstring(p, f->aname);
break;
case Tattach:
PBIT32(p, f->fid);
p += BIT32SZ;
PBIT32(p, f->afid);
p += BIT32SZ;
p = pstring(p, f->uname);
p = pstring(p, f->aname);
break;
case Twalk:
PBIT32(p, f->fid);
p += BIT32SZ;
PBIT32(p, f->newfid);
p += BIT32SZ;
PBIT16(p, f->nwname);
p += BIT16SZ;
if(f->nwname > MAXWELEM)
return 0;
for(i=0; i<f->nwname; i++)
p = pstring(p, f->wname[i]);
break;
case Topen:
PBIT32(p, f->fid);
p += BIT32SZ;
PBIT8(p, f->mode);
p += BIT8SZ;
break;
case Tcreate:
PBIT32(p, f->fid);
p += BIT32SZ;
p = pstring(p, f->name);
PBIT32(p, f->perm);
p += BIT32SZ;
PBIT8(p, f->mode);
p += BIT8SZ;
break;
case Tread:
PBIT32(p, f->fid);
p += BIT32SZ;
PBIT64(p, f->offset);
p += BIT64SZ;
PBIT32(p, f->count);
p += BIT32SZ;
break;
case Twrite:
PBIT32(p, f->fid);
p += BIT32SZ;
PBIT64(p, f->offset);
p += BIT64SZ;
PBIT32(p, f->count);
p += BIT32SZ;
memmove(p, f->data, f->count);
p += f->count;
break;
case Tclunk:
case Tremove:
PBIT32(p, f->fid);
p += BIT32SZ;
break;
case Tstat:
PBIT32(p, f->fid);
p += BIT32SZ;
break;
case Twstat:
PBIT32(p, f->fid);
p += BIT32SZ;
PBIT16(p, f->nstat);
p += BIT16SZ;
memmove(p, f->stat, f->nstat);
p += f->nstat;
break;
/*
*/
case Rversion:
PBIT32(p, f->msize);
p += BIT32SZ;
p = pstring(p, f->version);
break;
case Rerror:
p = pstring(p, f->ename);
break;
case Rflush:
break;
case Rauth:
p = pqid(p, &f->aqid);
break;
case Rattach:
p = pqid(p, &f->qid);
break;
case Rwalk:
PBIT16(p, f->nwqid);
p += BIT16SZ;
if(f->nwqid > MAXWELEM)
return 0;
for(i=0; i<f->nwqid; i++)
p = pqid(p, &f->wqid[i]);
break;
case Ropen:
case Rcreate:
p = pqid(p, &f->qid);
PBIT32(p, f->iounit);
p += BIT32SZ;
break;
case Rread:
PBIT32(p, f->count);
p += BIT32SZ;
memmove(p, f->data, f->count);
p += f->count;
break;
case Rwrite:
PBIT32(p, f->count);
p += BIT32SZ;
break;
case Rclunk:
break;
case Rremove:
break;
case Rstat:
PBIT16(p, f->nstat);
p += BIT16SZ;
memmove(p, f->stat, f->nstat);
p += f->nstat;
break;
case Rwstat:
break;
}
if(size != p-ap)
return 0;
return size;
}