Subversion Repositories planix.SVN

/*
 * 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->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->inuse; p++)
                if (strcmp(p->name, name) == 0) {
                        werrstr("partition name already in use");
                        return -1;
                }
        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
addparts(char *buf)
{
        char *f[4], *p, *q;

        /*
         * Use partitions passed from boot program,
         * e.g.
         *      sdC0part=dos 63 123123/plan9 123123 456456
         * This happens before /boot sets hostname so the
         * partitions will have the null-string for user.
         */
        for(p = buf; p != nil; p = q){
                if(q = strchr(p, '/'))
                        *q++ = '\0';
                if(tokenize(p, f, nelem(f)) >= 3 &&
                    addpart(f[0], strtoull(f[1], 0, 0), strtoull(f[2], 0, 0)) < 0)
                        fprint(2, "%s: addpart %s: %r\n", argv0, f[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(n == off){
                        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;
}

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] [-p 9parts] "
                "[-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, *parts;
        Dir *dir;

        quotefmtinstall();
        time0 = time(0);
        parts = nil;

        ARGBEGIN{
        case 'D':
                chatty9p++;
                break;
        case 'd':
                sdname = EARGF(usage());
                break;
        case 'm':
                mtpt = EARGF(usage());
                break;
        case 'p':
                parts = 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;

        /*
         * hack for booting from usb: add 9load partitions.
         */
        if(parts != nil)
                addparts(parts);

        postmountsrv(&fs, srvname, mtpt, MBEFORE);
        exits(nil);
}