ref: d39d1a5303541539f61488317b220c1eb724d7d3
dir: /sys/src/cmd/disk/partfs.c/
/*
* partfs - serve an underlying file, with devsd-style partitions
*/
#include <u.h>
#include <libc.h>
#include <auth.h>
#include <fcall.h>
#include <thread.h>
#include <9p.h>
typedef struct Part Part;
struct Part
{
int inuse;
int vers;
ulong mode;
char *name;
vlong offset; /* in sectors */
vlong length; /* in sectors */
};
enum
{
Qroot = 0,
Qdir,
Qctl,
Qpart,
};
int fd = -1, ctlfd = -1;
int rdonly;
ulong ctlmode = 0666;
ulong time0;
vlong nsect, sectsize;
char *inquiry = "partfs hard drive";
char *sdname = "sdXX";
Part tab[64];
char*
ctlstring(void)
{
Part *p;
Fmt fmt;
fmtstrinit(&fmt);
fmtprint(&fmt, "inquiry %s\n", inquiry);
fmtprint(&fmt, "geometry %lld %lld\n", nsect, sectsize);
for (p = tab; p < tab + nelem(tab); p++)
if (p->inuse)
fmtprint(&fmt, "part %s %lld %lld\n",
p->name, p->offset, p->offset + p->length);
return fmtstrflush(&fmt);
}
int
addpart(char *name, vlong start, vlong end)
{
Part *p;
if(start < 0 || start > end || end > nsect){
werrstr("bad partition boundaries");
return -1;
}
if (strcmp(name, "ctl") == 0 || strcmp(name, "data") == 0) {
werrstr("partition name already in use");
return -1;
}
for (p = tab; p < tab + nelem(tab); p++)
if (p->inuse && strcmp(p->name, name) == 0) {
/* adding identical partition is no-op */
if(p->offset == start && p->length == end - start)
return 0;
werrstr("partition name already in use");
return -1;
}
for (p = tab; p < tab + nelem(tab); p++)
if (!p->inuse)
break;
if(p == tab + nelem(tab)){
werrstr("no free partition slots");
return -1;
}
p->inuse = 1;
free(p->name);
p->name = estrdup9p(name);
p->offset = start;
p->length = end - start;
p->mode = ctlmode;
p->vers++;
return 0;
}
int
delpart(char *s)
{
Part *p;
for (p = tab; p < tab + nelem(tab); p++)
if(p->inuse && strcmp(p->name, s) == 0)
break;
if(p == tab + nelem(tab)){
werrstr("partition not found");
return -1;
}
p->inuse = 0;
free(p->name);
p->name = nil;
return 0;
}
static void
ctlwrite0(Req *r, char *msg, Cmdbuf *cb)
{
vlong start, end;
Part *p;
r->ofcall.count = r->ifcall.count;
if(cb->nf < 1){
respond(r, "empty control message");
return;
}
if(strcmp(cb->f[0], "part") == 0){
if(cb->nf != 4){
respondcmderror(r, cb, "part takes 3 args");
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");
return;
}
}
else if(strcmp(cb->f[0], "delpart") == 0){
if(cb->nf != 2){
respondcmderror(r, cb, "delpart takes 1 arg");
return;
}
if(delpart(cb->f[1]) < 0){
respondcmderror(r, cb, "%r");
return;
}
}
else if(strcmp(cb->f[0], "inquiry") == 0){
if(cb->nf != 2){
respondcmderror(r, cb, "inquiry takes 1 arg");
return;
}
free(inquiry);
inquiry = estrdup9p(cb->f[1]);
}
else if(strcmp(cb->f[0], "geometry") == 0){
if(cb->nf != 3){
respondcmderror(r, cb, "geometry takes 2 args");
return;
}
nsect = strtoll(cb->f[1], 0, 0);
sectsize = strtoll(cb->f[2], 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(p = tab; p < tab + nelem(tab); p++)
if(p->inuse && p->offset + p->length > nsect){
p->inuse = 0;
free(p->name);
p->name = nil;
}
} else
/* pass through to underlying ctl file, if any */
if (write(ctlfd, msg, r->ifcall.count) != r->ifcall.count) {
respondcmderror(r, cb, "%r");
return;
}
respond(r, nil);
}
void
ctlwrite(Req *r)
{
char *msg;
Cmdbuf *cb;
r->ofcall.count = r->ifcall.count;
msg = emalloc9p(r->ifcall.count+1);
memmove(msg, r->ifcall.data, r->ifcall.count);
msg[r->ifcall.count] = '\0';
cb = parsecmd(r->ifcall.data, r->ifcall.count);
ctlwrite0(r, msg, cb);
free(cb);
free(msg);
}
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("partfs");
d->gid = estrdup9p("partfs");
d->muid = estrdup9p("");
return 0;
}
return -1;
}
int
dirgen(int off, Dir *d, void*)
{
int n;
Part *p;
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(p = tab; p < tab + nelem(tab); p++, n++){
if(!p->inuse)
continue;
if(off-- == 0){
d->name = estrdup9p(p->name);
d->length = p->length*sectsize;
d->mode = p->mode;
d->qid.path = Qpart + p - tab;
d->qid.vers = p->vers;
goto Have;
}
}
return -1;
Have:
d->uid = estrdup9p("partfs");
d->gid = estrdup9p("partfs");
d->muid = estrdup9p("");
return 0;
}
void*
evommem(void *a, void *b, ulong n)
{
return memmove(b, a, n);
}
int
rdwrpart(Req *r)
{
int q;
long count, tot;
vlong offset;
uchar *dat;
Part *p;
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)
dat = (uchar*)r->ofcall.data;
else
dat = (uchar*)r->ifcall.data;
/* pass i/o through to underlying file */
seek(fd, offset, 0);
if (r->ifcall.type == Twrite) {
tot = write(fd, dat, count);
if (tot != count) {
respond(r, "%r");
return -1;
}
} else {
tot = read(fd, dat, count);
if (tot < 0) {
respond(r, "%r");
return -1;
}
}
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);
break;
case Qdir:
dirread9p(r, dirgen, nil);
break;
case Qctl:
s = ctlstring();
readstr(r, s);
free(s);
break;
default:
rdwrpart(r);
return;
}
respond(r, nil);
}
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;
case Qctl:
d->name = estrdup9p("ctl");
d->mode = 0666;
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("partfs");
d->gid = estrdup9p("partfs");
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)
{
Part *p;
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(p = tab; p < tab + nelem(tab); p++)
if(p->inuse && strcmp(p->name, name) == 0){
fid->qid.path = p - tab + Qpart;
fid->qid.vers = p->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: %s [-Dr] [-d sdname] [-m mtpt] [-s srvname] diskimage\n",
argv0);
fprint(2, "\tdefault mtpt is /dev\n");
exits("usage");
}
void
main(int argc, char **argv)
{
int isdir;
char *file, *cname;
Dir *dir;
quotefmtinstall();
time0 = time(0);
ARGBEGIN{
case 'D':
chatty9p++;
break;
case 'd':
sdname = EARGF(usage());
break;
case 'm':
mtpt = EARGF(usage());
break;
case 'r':
rdonly = 1;
break;
case 's':
srvname = EARGF(usage());
break;
default:
usage();
}ARGEND
if(argc != 1)
usage();
file = argv[0];
dir = dirstat(file);
if(!dir)
sysfatal("%s: %r", file);
isdir = (dir->mode & DMDIR) != 0;
free(dir);
if (isdir) {
cname = smprint("%s/ctl", file);
if ((ctlfd = open(cname, ORDWR)) < 0)
sysfatal("open %s: %r", cname);
file = smprint("%s/data", file);
}
if((fd = open(file, rdonly? OREAD: ORDWR)) < 0)
sysfatal("open %s: %r", file);
sectsize = 512; /* conventional */
dir = dirfstat(fd);
if (dir)
nsect = dir->length / sectsize;
free(dir);
inquiry = estrdup9p(inquiry);
tab[0].inuse = 1;
tab[0].name = estrdup9p("data");
tab[0].mode = 0666;
tab[0].length = nsect;
postmountsrv(&fs, srvname, mtpt, MBEFORE);
exits(nil);
}