ref: c3ba64f6935322f09b6de5c2285544fd471c605d
dir: /sys/src/cmd/aux/disksim.c/
#include <u.h>
#include <libc.h>
#include <auth.h>
#include <fcall.h>
#include <thread.h>
#include <9p.h>
typedef struct Part Part;
typedef struct Trip Trip;
typedef struct Dbl Dbl;
typedef struct Ind Ind;
/*
* with 8192-byte blocks and 4-byte pointers,
* double-indirect gets us 34 GB.
* triple-indirect gets us 70,368 GB.
*/
enum
{
LOGBLKSZ = 13,
BLKSZ = 1<<LOGBLKSZ, /* 8192 */
NPTR = BLKSZ/sizeof(void*),
};
static uchar zero[BLKSZ];
struct Trip
{
Dbl *dbl[NPTR];
};
struct Dbl
{
Ind *ind[NPTR];
};
struct Ind
{
uchar *blk[NPTR];
};
Trip trip;
struct Part
{
int inuse;
int vers;
ulong mode;
char *name;
vlong offset; /* in sectors */
vlong length; /* in sectors */
};
enum
{
Qroot = 0,
Qdir,
Qctl,
Qpart,
};
Part tab[64];
int fd = -1;
char *sdname = "sdXX";
ulong ctlmode = 0666;
char *inquiry = "aux/disksim hard drive";
vlong nsect, sectsize, c, h, s;
ulong time0;
int rdonly;
char*
ctlstring(void)
{
int i;
Fmt fmt;
fmtstrinit(&fmt);
fmtprint(&fmt, "inquiry %s\n", inquiry);
fmtprint(&fmt, "geometry %lld %lld %lld %lld %lld\n", nsect, sectsize, c, h, s);
for(i=0; i<nelem(tab); i++)
if(tab[i].inuse)
fmtprint(&fmt, "part %s %lld %lld\n", tab[i].name, tab[i].offset, tab[i].length);
return fmtstrflush(&fmt);
}
int
addpart(char *name, vlong start, vlong end)
{
int i;
if(start < 0 || start > end || end > nsect){
werrstr("bad partition boundaries");
return -1;
}
for(i=0; i<nelem(tab); i++)
if(tab[i].inuse == 0)
break;
if(i == nelem(tab)){
werrstr("no free partition slots");
return -1;
}
free(tab[i].name);
tab[i].inuse = 1;
tab[i].name = estrdup9p(name);
tab[i].offset = start;
tab[i].length = end - start;
tab[i].mode = ctlmode;
tab[i].vers++;
return 0;
}
int
delpart(char *s)
{
int i;
for(i=0; i<nelem(tab); i++)
if(tab[i].inuse && strcmp(tab[i].name, s) == 0)
break;
if(i==nelem(tab)){
werrstr("partition not found");
return -1;
}
tab[i].inuse = 0;
free(tab[i].name);
tab[i].name = 0;
return 0;
}
void
ctlwrite(Req *r)
{
int i;
Cmdbuf *cb;
vlong start, end;
r->ofcall.count = r->ifcall.count;
cb = parsecmd(r->ifcall.data, r->ifcall.count);
if(cb->nf < 1){
respond(r, "empty control message");
free(cb);
return;
}
if(strcmp(cb->f[0], "part") == 0){
if(cb->nf != 4){
respondcmderror(r, cb, "part takes 3 args");
free(cb);
return;
}
start = strtoll(cb->f[2], 0, 0);
end = strtoll(cb->f[3], 0, 0);
if(addpart(cb->f[1], start, end) < 0){
respondcmderror(r, cb, "%r");
free(cb);
return;
}
}
else if(strcmp(cb->f[0], "delpart") == 0){
if(cb->nf != 2){
respondcmderror(r, cb, "delpart takes 1 arg");
free(cb);
return;
}
if(delpart(cb->f[1]) < 0){
respondcmderror(r, cb, "%r");
free(cb);
return;
}
}
else if(strcmp(cb->f[0], "inquiry") == 0){
if(cb->nf != 2){
respondcmderror(r, cb, "inquiry takes 1 arg");
free(cb);
return;
}
free(inquiry);
inquiry = estrdup9p(cb->f[1]);
}
else if(strcmp(cb->f[0], "geometry") == 0){
if(cb->nf != 6){
respondcmderror(r, cb, "geometry takes 5 args");
free(cb);
return;
}
nsect = strtoll(cb->f[1], 0, 0);
sectsize = strtoll(cb->f[2], 0, 0);
c = strtoll(cb->f[3], 0, 0);
h = strtoll(cb->f[4], 0, 0);
s = strtoll(cb->f[5], 0, 0);
if(tab[0].inuse && strcmp(tab[0].name, "data") == 0 && tab[0].vers == 0){
tab[0].offset = 0;
tab[0].length = nsect;
}
for(i=0; i<nelem(tab); i++){
if(tab[i].inuse && tab[i].offset+tab[i].length > nsect){
tab[i].inuse = 0;
free(tab[i].name);
tab[i].name = 0;
}
}
}
else{
respondcmderror(r, cb, "unknown control message");
free(cb);
return;
}
free(cb);
respond(r, nil);
}
void*
allocblk(vlong addr)
{
uchar *op;
static uchar *p;
static ulong n;
if(n == 0){
p = malloc(4*1024*1024);
if(p == 0)
sysfatal("out of memory");
n = 4*1024*1024;
}
op = p;
p += BLKSZ;
n -= BLKSZ;
memset(op, 0, BLKSZ);
if(fd != -1 && addr != -1)
pread(fd, op, BLKSZ, addr);
return op;
}
uchar*
getblock(vlong addr, int alloc)
{
Dbl *p2;
Ind *p1;
uchar *p0;
uint i0, i1, i2;
vlong oaddr;
if(fd >= 0)
alloc = 1;
addr >>= LOGBLKSZ;
oaddr = addr<<LOGBLKSZ;
i0 = addr % NPTR;
addr /= NPTR;
i1 = addr % NPTR;
addr /= NPTR;
i2 = addr % NPTR;
addr /= NPTR;
assert(addr == 0);
if((p2 = trip.dbl[i2]) == 0){
if(!alloc)
return zero;
trip.dbl[i2] = p2 = allocblk(-1);
}
if((p1 = p2->ind[i1]) == 0){
if(!alloc)
return zero;
p2->ind[i1] = p1 = allocblk(-1);
}
if((p0 = p1->blk[i0]) == 0){
if(!alloc)
return zero;
p1->blk[i0] = p0 = allocblk(oaddr);
}
return p0;
}
void
dirty(vlong addr, uchar *buf)
{
vlong oaddr;
if(fd == -1 || rdonly)
return;
oaddr = addr&~((vlong)BLKSZ-1);
if(pwrite(fd, buf, BLKSZ, oaddr) != BLKSZ)
sysfatal("write: %r");
}
int
rootgen(int off, Dir *d, void*)
{
memset(d, 0, sizeof *d);
d->atime = time0;
d->mtime = time0;
if(off == 0){
d->name = estrdup9p(sdname);
d->mode = DMDIR|0777;
d->qid.path = Qdir;
d->qid.type = QTDIR;
d->uid = estrdup9p("disksim");
d->gid = estrdup9p("disksim");
d->muid = estrdup9p("");
return 0;
}
return -1;
}
int
dirgen(int off, Dir *d, void*)
{
int n, j;
memset(d, 0, sizeof *d);
d->atime = time0;
d->mtime = time0;
if(off == 0){
d->name = estrdup9p("ctl");
d->mode = ctlmode;
d->qid.path = Qctl;
goto Have;
}
off--;
n = 0;
for(j=0; j<nelem(tab); j++){
if(tab[j].inuse==0)
continue;
if(n == off){
d->name = estrdup9p(tab[j].name);
d->length = tab[j].length*sectsize;
d->mode = tab[j].mode;
d->qid.path = Qpart+j;
d->qid.vers = tab[j].vers;
goto Have;
}
n++;
}
return -1;
Have:
d->uid = estrdup9p("disksim");
d->gid = estrdup9p("disksim");
d->muid = estrdup9p("");
return 0;
}
void*
evommem(void *a, void *b, usize n)
{
return memmove(b, a, n);
}
int
isnonzero(void *v, usize n)
{
uchar *a, *ea;
a = v;
ea = a+n;
for(; a<ea; a++)
if(*a)
return 1;
return 0;
}
int
rdwrpart(Req *r)
{
int q, nonzero;
Part *p;
vlong offset;
long count, tot, n, o;
uchar *blk, *dat;
void *(*move)(void*, void*, usize);
q = r->fid->qid.path-Qpart;
if(q < 0 || q > nelem(tab) || !tab[q].inuse || tab[q].vers != r->fid->qid.vers){
respond(r, "unknown partition");
return -1;
}
p = &tab[q];
offset = r->ifcall.offset;
count = r->ifcall.count;
if(offset < 0){
respond(r, "negative offset");
return -1;
}
if(count < 0){
respond(r, "negative count");
return -1;
}
if(offset > p->length*sectsize){
respond(r, "offset past end of partition");
return -1;
}
if(offset+count > p->length*sectsize)
count = p->length*sectsize - offset;
offset += p->offset*sectsize;
if(r->ifcall.type == Tread)
move = memmove;
else
move = evommem;
tot = 0;
nonzero = 1;
if(r->ifcall.type == Tread)
dat = (uchar*)r->ofcall.data;
else{
dat = (uchar*)r->ifcall.data;
nonzero = isnonzero(dat, r->ifcall.count);
}
o = offset & (BLKSZ-1);
/* left fringe block */
if(o && count){
blk = getblock(offset, r->ifcall.type==Twrite && nonzero);
n = BLKSZ - o;
if(n > count)
n = count;
if(r->ifcall.type != Twrite || blk != zero)
(*move)(dat, blk+o, n);
if(r->ifcall.type == Twrite)
dirty(offset, blk);
tot += n;
}
/* full and right fringe blocks */
while(tot < count){
blk = getblock(offset+tot, r->ifcall.type==Twrite && nonzero);
n = BLKSZ;
if(n > count-tot)
n = count-tot;
if(r->ifcall.type != Twrite || blk != zero)
(*move)(dat+tot, blk, n);
if(r->ifcall.type == Twrite)
dirty(offset+tot, blk);
tot += n;
}
r->ofcall.count = tot;
respond(r, nil);
return 0;
}
void
fsread(Req *r)
{
char *s;
switch((int)r->fid->qid.path){
case Qroot:
dirread9p(r, rootgen, nil);
respond(r, nil);
break;
case Qdir:
dirread9p(r, dirgen, nil);
respond(r, nil);
break;
case Qctl:
s = ctlstring();
readstr(r, s);
free(s);
respond(r, nil);
break;
default:
rdwrpart(r);
break;
}
}
void
fswrite(Req *r)
{
switch((int)r->fid->qid.path){
case Qroot:
case Qdir:
respond(r, "write to a directory?");
break;
case Qctl:
ctlwrite(r);
break;
default:
rdwrpart(r);
break;
}
}
void
fsopen(Req *r)
{
if(r->ifcall.mode&ORCLOSE)
respond(r, "cannot open ORCLOSE");
switch((int)r->fid->qid.path){
case Qroot:
case Qdir:
if(r->ifcall.mode != OREAD){
respond(r, "bad mode for directory open");
return;
}
}
respond(r, nil);
}
void
fsstat(Req *r)
{
int q;
Dir *d;
Part *p;
d = &r->d;
memset(d, 0, sizeof *d);
d->qid = r->fid->qid;
d->atime = d->mtime = time0;
q = r->fid->qid.path;
switch(q){
case Qroot:
d->name = estrdup9p("/");
d->mode = DMDIR|0777;
break;
case Qdir:
d->name = estrdup9p(sdname);
d->mode = DMDIR|0777;
break;
default:
q -= Qpart;
if(q < 0 || q > nelem(tab) || tab[q].inuse==0 || r->fid->qid.vers != tab[q].vers){
respond(r, "partition no longer exists");
return;
}
p = &tab[q];
d->name = estrdup9p(p->name);
d->length = p->length * sectsize;
d->mode = p->mode;
break;
}
d->uid = estrdup9p("disksim");
d->gid = estrdup9p("disksim");
d->muid = estrdup9p("");
respond(r, nil);
}
void
fsattach(Req *r)
{
char *spec;
spec = r->ifcall.aname;
if(spec && spec[0]){
respond(r, "invalid attach specifier");
return;
}
r->ofcall.qid = (Qid){Qroot, 0, QTDIR};
r->fid->qid = r->ofcall.qid;
respond(r, nil);
}
char*
fswalk1(Fid *fid, char *name, Qid *qid)
{
int i;
switch((int)fid->qid.path){
case Qroot:
if(strcmp(name, sdname) == 0){
fid->qid.path = Qdir;
fid->qid.type = QTDIR;
*qid = fid->qid;
return nil;
}
break;
case Qdir:
if(strcmp(name, "ctl") == 0){
fid->qid.path = Qctl;
fid->qid.vers = 0;
fid->qid.type = 0;
*qid = fid->qid;
return nil;
}
for(i=0; i<nelem(tab); i++){
if(tab[i].inuse && strcmp(tab[i].name, name) == 0){
fid->qid.path = i+Qpart;
fid->qid.vers = tab[i].vers;
fid->qid.type = 0;
*qid = fid->qid;
return nil;
}
}
break;
}
return "file not found";
}
Srv fs = {
.attach= fsattach,
.open= fsopen,
.read= fsread,
.write= fswrite,
.stat= fsstat,
.walk1= fswalk1,
};
char *mtpt = "/dev";
char *srvname;
void
usage(void)
{
fprint(2, "usage: aux/disksim [-D] [-f file] [-s srvname] [-m mtpt] [sdXX]\n");
fprint(2, "\tdefault mtpt is /dev\n");
exits("usage");
}
void
main(int argc, char **argv)
{
char *file;
file = nil;
quotefmtinstall();
time0 = time(0);
ARGBEGIN{
case 'D':
chatty9p++;
break;
case 'f':
file = EARGF(usage());
break;
case 'r':
rdonly = 1;
break;
case 's':
srvname = EARGF(usage());
break;
case 'm':
mtpt = EARGF(usage());
break;
default:
usage();
}ARGEND
if(argc > 1)
usage();
if(argc == 1)
sdname = argv[0];
if(file){
if((fd = open(file, rdonly ? OREAD : ORDWR)) < 0)
sysfatal("open %s: %r", file);
}
inquiry = estrdup9p(inquiry);
tab[0].name = estrdup9p("data");
tab[0].inuse = 1;
tab[0].mode = 0666;
postmountsrv(&fs, srvname, mtpt, MBEFORE);
exits(nil);
}