ref: 8726990cf563f72d91e1cb8335510d5a1d38ec02
dir: /sys/src/cmd/lnfs.c/
#include <u.h>
#include <libc.h>
#include <bio.h>
#include <auth.h>
#include <fcall.h>
#include <String.h>
#include <libsec.h>
enum
{
OPERM = 0x3, /* mask of all permission types in open mode */
Maxsize = 512*1024*1024,
Maxfdata = 8192,
NAMELEN = 28,
};
typedef struct Fid Fid;
struct Fid
{
short busy;
int fid;
Fid *next;
char *user;
String *path; /* complete path */
int fd; /* set on open or create */
Qid qid; /* set on open or create */
int attach; /* this is an attach fd */
ulong diroff; /* directory offset */
Dir *dir; /* directory entries */
int ndir; /* number of directory entries */
};
Fid *fids;
int mfd[2];
char *user;
uchar mdata[IOHDRSZ+Maxfdata];
uchar rdata[Maxfdata]; /* buffer for data in reply */
uchar statbuf[STATMAX];
Fcall thdr;
Fcall rhdr;
int messagesize = sizeof mdata;
int readonly;
char *srvname;
int debug;
Fid * newfid(int);
void io(void);
void *erealloc(void*, ulong);
void *emalloc(ulong);
char *estrdup(char*);
void usage(void);
void fidqid(Fid*, Qid*);
char* short2long(char*);
char* long2short(char*, int);
void readnames(void);
void post(char*, int);
char *rflush(Fid*), *rversion(Fid*), *rauth(Fid*),
*rattach(Fid*), *rwalk(Fid*),
*ropen(Fid*), *rcreate(Fid*),
*rread(Fid*), *rwrite(Fid*), *rclunk(Fid*),
*rremove(Fid*), *rstat(Fid*), *rwstat(Fid*);
char *(*fcalls[])(Fid*) = {
[Tversion] rversion,
[Tflush] rflush,
[Tauth] rauth,
[Tattach] rattach,
[Twalk] rwalk,
[Topen] ropen,
[Tcreate] rcreate,
[Tread] rread,
[Twrite] rwrite,
[Tclunk] rclunk,
[Tremove] rremove,
[Tstat] rstat,
[Twstat] rwstat,
};
char Eperm[] = "permission denied";
char Enotdir[] = "not a directory";
char Enoauth[] = "lnfs: authentication not required";
char Enotexist[] = "file does not exist";
char Einuse[] = "file in use";
char Eexist[] = "file exists";
char Eisdir[] = "file is a directory";
char Enotowner[] = "not owner";
char Eisopen[] = "file already open for I/O";
char Excl[] = "exclusive use file already open";
char Ename[] = "illegal name";
char Eversion[] = "unknown 9P version";
void
usage(void)
{
fprint(2, "usage: %s [-r] [-s srvname] mountpoint\n", argv0);
exits("usage");
}
void
notifyf(void *a, char *s)
{
USED(a);
if(strncmp(s, "interrupt", 9) == 0)
noted(NCONT);
noted(NDFLT);
}
void
main(int argc, char *argv[])
{
char *defmnt;
int p[2];
Dir *d;
ARGBEGIN{
case 'r':
readonly = 1;
break;
case 'd':
debug = 1;
break;
case 's':
srvname = ARGF();
if(srvname == nil)
usage();
break;
default:
usage();
}ARGEND
if(argc < 1)
usage();
defmnt = argv[0];
d = dirstat(defmnt);
if(d == nil || !(d->qid.type & QTDIR))
sysfatal("mountpoint must be an accessible directory");
free(d);
if(pipe(p) < 0)
sysfatal("pipe failed");
mfd[0] = p[0];
mfd[1] = p[0];
user = getuser();
notify(notifyf);
if(srvname != nil)
post(srvname, p[1]);
if(debug)
fmtinstall('F', fcallfmt);
switch(rfork(RFFDG|RFPROC|RFNAMEG|RFNOTEG)){
case -1:
sysfatal("fork: %r");
case 0:
close(p[1]);
chdir(defmnt);
io();
break;
default:
close(p[0]); /* don't deadlock if child fails */
if(mount(p[1], -1, defmnt, MREPL|MCREATE, "") < 0)
sysfatal("mount failed: %r");
}
exits(0);
}
void
post(char *srvname, int pfd)
{
char name[128];
int fd;
snprint(name, sizeof name, "#s/%s", srvname);
fd = create(name, OWRITE, 0666);
if(fd < 0)
sysfatal("create of %s failed: %r", srvname);
sprint(name, "%d", pfd);
if(write(fd, name, strlen(name)) < 0)
sysfatal("writing %s: %r", srvname);
}
char*
rversion(Fid*)
{
Fid *f;
for(f = fids; f; f = f->next)
if(f->busy)
rclunk(f);
if(thdr.msize > sizeof mdata)
rhdr.msize = sizeof mdata;
else
rhdr.msize = thdr.msize;
messagesize = rhdr.msize;
if(strncmp(thdr.version, "9P2000", 6) != 0)
return Eversion;
rhdr.version = "9P2000";
return nil;
}
char*
rauth(Fid*)
{
return Enoauth;
}
char*
rflush(Fid *f)
{
USED(f);
return nil;
}
char*
rattach(Fid *f)
{
/* no authentication! */
f->busy = 1;
if(thdr.uname[0])
f->user = estrdup(thdr.uname);
else
f->user = "none";
if(strcmp(user, "none") == 0)
user = f->user;
if(f->path)
s_free(f->path);
f->path = s_copy(".");
fidqid(f, &rhdr.qid);
f->attach = 1;
return nil;
}
char*
clone(Fid *f, Fid **nf)
{
if(f->fd >= 0)
return Eisopen;
*nf = newfid(thdr.newfid);
(*nf)->busy = 1;
if((*nf)->path)
s_free((*nf)->path);
(*nf)->path = s_clone(f->path);
(*nf)->fd = -1;
(*nf)->user = f->user;
(*nf)->attach = 0;
return nil;
}
char*
rwalk(Fid *f)
{
char *name;
Fid *nf;
char *err;
int i;
String *npath;
Dir *d;
char *cp;
Qid qid;
err = nil;
nf = nil;
rhdr.nwqid = 0;
if(rhdr.newfid != rhdr.fid){
err = clone(f, &nf);
if(err)
return err;
f = nf; /* walk the new fid */
}
readnames();
npath = s_clone(f->path);
if(thdr.nwname > 0){
for(i=0; i<thdr.nwname && i<MAXWELEM; i++){
name = long2short(thdr.wname[i], 0);
if(strcmp(name, ".") == 0){
;
} else if(strcmp(name, "..") == 0){
cp = strrchr(s_to_c(npath), '/');
if(cp != nil){
*cp = 0;
npath->ptr = cp;
}
} else {
s_append(npath, "/");
s_append(npath, name);
}
d = dirstat(s_to_c(npath));
if(d == nil)
break;
rhdr.nwqid++;
qid = d->qid;
rhdr.wqid[i] = qid;
free(d);
}
if(i==0 && err == nil)
err = Enotexist;
}
/* if there was an error and we cloned, get rid of the new fid */
if(nf != nil && (err!=nil || rhdr.nwqid<thdr.nwname)){
f->busy = 0;
s_free(npath);
}
/* update the fid after a successful walk */
if(rhdr.nwqid == thdr.nwname){
s_free(f->path);
f->path = npath;
}
return err;
}
static char*
passerror(void)
{
static char err[256];
rerrstr(err, sizeof err);
return err;
}
char*
ropen(Fid *f)
{
if(readonly && (thdr.mode & 3))
return Eperm;
if(f->fd >= 0)
return Eisopen;
f->fd = open(s_to_c(f->path), thdr.mode);
if(f->fd < 0)
return passerror();
fidqid(f, &rhdr.qid);
f->qid = rhdr.qid;
rhdr.iounit = messagesize-IOHDRSZ;
return nil;
}
char*
rcreate(Fid *f)
{
char *name;
if(readonly)
return Eperm;
readnames();
name = long2short(thdr.name, 1);
if(f->fd >= 0)
return Eisopen;
s_append(f->path, "/");
s_append(f->path, name);
f->fd = create(s_to_c(f->path), thdr.mode, thdr.perm);
if(f->fd < 0)
return passerror();
fidqid(f, &rhdr.qid);
f->qid = rhdr.qid;
rhdr.iounit = messagesize-IOHDRSZ;
return nil;
}
char*
rreaddir(Fid *f)
{
int i;
int n;
/* reread the directory */
if(thdr.offset == 0){
if(f->dir)
free(f->dir);
f->dir = nil;
if(f->diroff != 0)
seek(f->fd, 0, 0);
f->ndir = dirreadall(f->fd, &f->dir);
f->diroff = 0;
if(f->ndir < 0)
return passerror();
readnames();
for(i = 0; i < f->ndir; i++)
f->dir[i].name = short2long(f->dir[i].name);
}
/* copy in as many directory entries as possible */
for(n = 0; f->diroff < f->ndir; n += i){
i = convD2M(&f->dir[f->diroff], rdata+n, thdr.count - n);
if(i <= BIT16SZ)
break;
f->diroff++;
}
rhdr.data = (char*)rdata;
rhdr.count = n;
return nil;
}
char*
rread(Fid *f)
{
long n;
if(f->fd < 0)
return Enotexist;
if(thdr.count > messagesize-IOHDRSZ)
thdr.count = messagesize-IOHDRSZ;
if(f->qid.type & QTDIR)
return rreaddir(f);
n = pread(f->fd, rdata, thdr.count, thdr.offset);
if(n < 0)
return passerror();
rhdr.data = (char*)rdata;
rhdr.count = n;
return nil;
}
char*
rwrite(Fid *f)
{
long n;
if(readonly || (f->qid.type & QTDIR))
return Eperm;
if(f->fd < 0)
return Enotexist;
if(thdr.count > messagesize-IOHDRSZ) /* shouldn't happen, anyway */
thdr.count = messagesize-IOHDRSZ;
n = pwrite(f->fd, thdr.data, thdr.count, thdr.offset);
if(n < 0)
return passerror();
rhdr.count = n;
return nil;
}
char*
rclunk(Fid *f)
{
f->busy = 0;
close(f->fd);
f->fd = -1;
f->path = s_reset(f->path);
if(f->attach){
free(f->user);
f->user = nil;
}
f->attach = 0;
if(f->dir != nil){
free(f->dir);
f->dir = nil;
}
f->diroff = f->ndir = 0;
return nil;
}
char*
rremove(Fid *f)
{
if(remove(s_to_c(f->path)) < 0)
return passerror();
return nil;
}
char*
rstat(Fid *f)
{
int n;
Dir *d;
d = dirstat(s_to_c(f->path));
if(d == nil)
return passerror();
d->name = short2long(d->name);
n = convD2M(d, statbuf, sizeof statbuf);
free(d);
if(n <= BIT16SZ)
return passerror();
rhdr.nstat = n;
rhdr.stat = statbuf;
return nil;
}
char*
rwstat(Fid *f)
{
int n;
Dir d;
if(readonly)
return Eperm;
convM2D(thdr.stat, thdr.nstat, &d, (char*)rdata);
d.name = long2short(d.name, 1);
n = dirwstat(s_to_c(f->path), &d);
if(n < 0)
return passerror();
return nil;
}
Fid *
newfid(int fid)
{
Fid *f, *ff;
ff = 0;
for(f = fids; f; f = f->next)
if(f->fid == fid)
return f;
else if(!ff && !f->busy)
ff = f;
if(ff){
ff->fid = fid;
return ff;
}
f = emalloc(sizeof *f);
f->path = s_reset(f->path);
f->fd = -1;
f->fid = fid;
f->next = fids;
fids = f;
return f;
}
void
io(void)
{
char *err;
int n, pid;
pid = getpid();
for(;;){
/*
* reading from a pipe or a network device
* will give an error after a few eof reads.
* however, we cannot tell the difference
* between a zero-length read and an interrupt
* on the processes writing to us,
* so we wait for the error.
*/
n = read9pmsg(mfd[0], mdata, messagesize);
if(n < 0)
sysfatal("mount read");
if(n == 0)
continue;
if(convM2S(mdata, n, &thdr) == 0)
continue;
if(debug)
fprint(2, "%s %d:<-%F\n", argv0, pid, &thdr);
if(!fcalls[thdr.type])
err = "bad fcall type";
else
err = (*fcalls[thdr.type])(newfid(thdr.fid));
if(err){
rhdr.type = Rerror;
rhdr.ename = err;
}else{
rhdr.type = thdr.type + 1;
rhdr.fid = thdr.fid;
}
rhdr.tag = thdr.tag;
if(debug)
fprint(2, "%s %d:->%F\n", argv0, pid, &rhdr);/**/
n = convS2M(&rhdr, mdata, messagesize);
if(n == 0)
sysfatal("convS2M error on write");
if(write(mfd[1], mdata, n) != n)
sysfatal("mount write");
}
}
void *
emalloc(ulong n)
{
void *p;
p = malloc(n);
if(!p)
sysfatal("out of memory");
memset(p, 0, n);
return p;
}
void *
erealloc(void *p, ulong n)
{
p = realloc(p, n);
if(!p)
sysfatal("out of memory");
return p;
}
char *
estrdup(char *q)
{
char *p;
int n;
n = strlen(q)+1;
p = malloc(n);
if(!p)
sysfatal("out of memory");
memmove(p, q, n);
return p;
}
void
fidqid(Fid *f, Qid *q)
{
Dir *d;
d = dirstat(s_to_c(f->path));
if(d == nil)
*q = (Qid){0, 0, QTFILE};
else {
*q = d->qid;
free(d);
}
}
/*
* table of name translations
*
* the file ./.longnames contains all the known long names.
* the short name is the first NAMELEN-1 bytes of the base64
* encoding of the MD5 hash of the longname.
*/
typedef struct Name Name;
struct Name
{
Name *next;
char shortname[NAMELEN];
char *longname;
};
Dir *dbstat; /* last stat of the name file */
char *namefile = "./.longnames";
char *namebuf;
Name *names;
Name*
newname(char *longname, int writeflag)
{
Name *np;
int n;
uchar digest[MD5dlen];
int fd;
/* chain in new name */
n = strlen(longname);
np = emalloc(sizeof(*np)+n+1);
np->longname = (char*)&np[1];
strcpy(np->longname, longname);
md5((uchar*)longname, n, digest, nil);
enc32(np->shortname, sizeof(np->shortname), digest, MD5dlen);
np->next = names;
names = np;
/* don't change namefile if we're read only */
if(!writeflag)
return np;
/* add to namefile */
fd = open(namefile, OWRITE);
if(fd >= 0){
seek(fd, 0, 2);
fprint(fd, "%s\n", longname);
close(fd);
}
return np;
}
void
freenames(void)
{
Name *np, *next;
for(np = names; np != nil; np = next){
next = np->next;
free(np);
}
names = nil;
}
/*
* reread the file if the qid.path has changed.
*
* read any new entries if length has changed.
*/
void
readnames(void)
{
Dir *d;
int fd;
vlong offset;
Biobuf *b;
char *p;
d = dirstat(namefile);
if(d == nil){
if(readonly)
return;
/* create file if it doesn't exist */
fd = create(namefile, OREAD, DMAPPEND|0666);
if(fd < 0)
return;
if(dbstat != nil)
free(dbstat);
dbstat = nil;
close(fd);
return;
}
/* up to date? */
offset = 0;
if(dbstat != nil){
if(d->qid.path == dbstat->qid.path){
if(d->length <= dbstat->length){
free(d);
return;
}
offset = dbstat->length;
} else {
freenames();
}
free(dbstat);
dbstat = nil;
}
/* read file */
b = Bopen(namefile, OREAD);
if(b == nil){
free(d);
return;
}
Bseek(b, offset, 0);
while((p = Brdline(b, '\n')) != nil){
p[Blinelen(b)-1] = 0;
newname(p, 0);
}
Bterm(b);
dbstat = d;
}
/*
* look up a long name, if it doesn't exist in the
* file, add an entry to the file if the writeflag is
* non-zero. Return a pointer to the short name.
*/
char*
long2short(char *longname, int writeflag)
{
Name *np;
if(strlen(longname) < NAMELEN-1 && strpbrk(longname, " ")==nil)
return longname;
for(np = names; np != nil; np = np->next)
if(strcmp(longname, np->longname) == 0)
return np->shortname;
if(!writeflag)
return longname;
np = newname(longname, !readonly);
return np->shortname;
}
/*
* look up a short name, if it doesn't exist, return the
* longname.
*/
char*
short2long(char *shortname)
{
Name *np;
for(np = names; np != nil; np = np->next)
if(strcmp(shortname, np->shortname) == 0)
return np->longname;
return shortname;
}