ref: b548687a8ed1d0a159c9d3f3f921d93bbb56908e
dir: /appl/cmd/zip/zipfs.b/
# zipfs design
#
# at startup we read the entire central directory,
# set up a styxservers nametree and serve from that.
# bit 62 of the qid denotes the directory bit.
#
# if a file is not compressed and -p was set, we read directly through
# the zipfile's fd (no crc protection).
# otherwise, on first read of a file, we open a fd for that file.
# sequential or higher-than-current offset reads reuse the fd.
# random reads to before the current offset reopen the file and
# seek to the desired location by reading & discarding data.
implement Zipfs;
include "sys.m";
sys: Sys;
sprint: import sys;
include "draw.m";
include "arg.m";
include "bufio.m";
bufio: Bufio;
Iobuf: import bufio;
include "string.m";
str: String;
include "daytime.m";
daytime: Daytime;
include "styx.m";
styx: Styx;
Tmsg, Rmsg: import Styx;
include "styxservers.m";
styxservers: Styxservers;
Styxserver, Fid, Navigator, Navop: import styxservers;
nametree: Nametree;
Tree: import nametree;
include "tables.m";
tables: Tables;
Table, Strhash: import tables;
include "zip.m";
zip: Zip;
Fhdr, CDFhdr, Endofcdir: import zip;
Zipfs: module {
init: fn(nil: ref Draw->Context, args: list of string);
};
# directories for styx nametree
Zdir: adt {
name: string;
qid: big;
pqid: big;
};
# opened file from zip archive
Zfile: adt {
fid: int;
fd: ref Sys->FD;
off: big;
cdf: ref CDFhdr;
f: ref Fhdr;
};
Qiddir: con big 1<<62;
zipfd: ref Sys->FD;
srv: ref Styxserver;
files: array of ref Fhdr;
zdirs: ref Strhash[ref Zdir]; # indexed by full path without trailing slash
rootzdir: ref Zdir;
dirgen: int;
cdirfhdrs: array of ref CDFhdr;
zfiles: ref Table[ref Zfile]; # indexed by fid
Dflag: int;
dflag: int;
pflag: int;
now: int;
init(nil: ref Draw->Context, args: list of string)
{
sys = load Sys Sys->PATH;
arg := load Arg Arg->PATH;
bufio = load Bufio Bufio->PATH;
str = load String String->PATH;
daytime = load Daytime Daytime->PATH;
styx = load Styx Styx->PATH;
styx->init();
styxservers = load Styxservers Styxservers->PATH;
styxservers->init(styx);
nametree = load Nametree Nametree->PATH;
nametree->init();
tables = load Tables Tables->PATH;
zip = load Zip Zip->PATH;
zip->init();
# for zip library
sys->pctl(Sys->NEWPGRP|Sys->FORKNS, nil);
if(sys->bind("#s", "/chan", Sys->MREPL) < 0)
fail(sprint("bind /chan: %r"));
arg->init(args);
arg->setusage(arg->progname()+" [-Ddp] zipfile");
while((c := arg->opt()) != 0)
case c {
'D' => styxservers->traceset(Dflag++);
'd' => zip->dflag = dflag++;
'p' => pflag++;
* => arg->usage();
}
args = arg->argv();
if(len args != 1)
arg->usage();
zdirs = zdirs.new(101, nil);
zipfd = sys->open(hd args, Sys->OREAD);
if(zipfd == nil)
fail(sprint("open: %r"));
err: string;
(nil, cdirfhdrs, err) = zip->open(zipfd);
if(err != nil)
fail("parsing zip: "+err);
now = daytime->now();
(tree, treeop) := nametree->start();
rzd := rootzdir = ref Zdir (".", big 0|Qiddir, big 0|Qiddir);
tree.create(rzd.pqid, dir(rzd.name, rzd.qid, now, big 0));
for(i := 0; i < len cdirfhdrs; i++) {
f := cdirfhdrs[i];
fs := f.filename;
(path, name) := str->splitstrr(fs, "/");
zd := ensuredir(tree, path);
if(fs == nil || fs[len fs-1] == '/')
continue;
qid := big (i+1);
tree.create(zd.qid, dir(name, qid, f.mtime, f.uncomprsize));
}
zdirs = nil;
zfiles = zfiles.new(31, nil);
msgc: chan of ref Tmsg;
(msgc, srv) = Styxserver.new(sys->fildes(0), Navigator.new(treeop), big 0|Qiddir);
spawn styxsrv(msgc);
}
# inefficient
# called with empty string (denoting the root directory), or path with trailing slash
ensuredir(tree: ref Tree, s: string): ref Zdir
{
if(s == nil)
return rootzdir;
s = s[:len s-1];
zd := zdirs.find(s);
if(zd != nil)
return zd;
(ppath, name) := str->splitstrr(s, "/");
pzd := ensuredir(tree, ppath);
zd = ref Zdir (name, big ++dirgen|Qiddir, pzd.qid);
tree.create(pzd.qid, dir(zd.name, zd.qid, now, big 0));
zdirs.add(s, zd);
return zd;
}
dir(name: string, qid: big, mtime: int, length: big): Sys->Dir
{
d := sys->zerodir;
d.name = name;
d.uid = "zip";
d.gid = "zip";
d.qid.path = qid;
if((qid & Qiddir) != big 0) {
d.qid.qtype = Sys->QTDIR;
d.mode = Sys->DMDIR|8r555;
} else {
d.qid.qtype = Sys->QTFILE;
d.mode = 8r444;
}
d.mtime = d.atime = mtime;
d.length = length;
return d;
}
styxsrv(msgc: chan of ref Tmsg)
{
done:
for(;;) alt {
mm := <-msgc =>
if(mm == nil)
break done;
pick m := mm {
Readerror =>
warn("read error: "+m.error);
break done;
}
dostyx(mm);
}
killgrp(sys->pctl(0, nil));
}
openzfile(fid: int, qid: big): (ref Zfile, string)
{
cdf := cdirfhdrs[int qid-1];
zf := ref Zfile (fid, nil, big 0, cdf, nil);
err: string;
if(pflag && cdf.comprmethod == zip->Mplain)
(zf.f, err) = zip->readfhdr(zipfd, cdf);
else
(zf.fd, nil, err) = zip->openfile(zipfd, cdf);
if(err != nil)
return (nil, err);
if(Dflag) warn("zipfs: "+cdf.filename);
zfiles.add(fid, zf);
return (zf, nil);
}
zfileseek(zf: ref Zfile, off: big): string
{
if(zf.off == off)
return nil;
if(off < zf.off) {
(fd, nil, err) := zip->openfile(zipfd, zf.cdf);
if(err != nil)
return err;
zf.fd = fd;
zf.off = big 0;
}
n := int (off-zf.off);
buf := array[Sys->ATOMICIO] of byte;
while(n > 0) {
nn := sys->read(zf.fd, buf, len buf);
if(nn < 0)
return sprint("seeking to requested offset: %r");
if(nn == 0)
break; # not there yet, but subsequent reads on zf.fd will/should return eof too
zf.off += big nn;
n -= nn;
}
return nil;
}
dostyx(mm: ref Tmsg)
{
pick m := mm {
Clunk or
Remove =>
f := srv.getfid(m.fid);
if(f != nil && f.isopen && (f.path & Qiddir) == big 0)
zfiles.del(m.fid);
srv.default(m);
Read =>
f := srv.getfid(m.fid);
if(f.qtype & Sys->QTDIR)
return srv.default(m);
zf := zfiles.find(m.fid);
if(zf == nil) {
err: string;
(zf, err) = openzfile(m.fid, f.path);
if(err != nil)
return replyerror(m, err);
}
if(zf.f == nil) {
err := zfileseek(zf, m.offset);
if(err != nil)
return replyerror(m, err);
n := sys->read(zf.fd, buf := array[m.count] of byte, len buf);
if(n < 0)
return replyerror(m, sprint("%r"));
zf.off += big n;
srv.reply(ref Rmsg.Read(m.tag, buf[:n]));
} else {
n := zip->pread(zipfd, zf.f, buf := array[m.count] of byte, len buf, m.offset);
if(n < 0)
return replyerror(m, sprint("%r"));
srv.reply(ref Rmsg.Read(m.tag, buf[:n]));
}
* =>
srv.default(mm);
}
}
replyerror(m: ref Tmsg, s: string)
{
srv.reply(ref Rmsg.Error(m.tag, s));
}
killgrp(pid: int)
{
sys->fprint(sys->open(sprint("/prog/%d/ctl", pid), Sys->OWRITE), "killgrp");
}
warn(s: string)
{
sys->fprint(sys->fildes(2), "%s\n", s);
}
say(s: string)
{
if(dflag)
warn(s);
}
fail(s: string)
{
warn(s);
raise "fail:"+s;
}