diff options
Diffstat (limited to 'man/2/styxservers-nametree')
| -rw-r--r-- | man/2/styxservers-nametree | 180 |
1 files changed, 180 insertions, 0 deletions
diff --git a/man/2/styxservers-nametree b/man/2/styxservers-nametree new file mode 100644 index 00000000..f64e519a --- /dev/null +++ b/man/2/styxservers-nametree @@ -0,0 +1,180 @@ +.TH STYXSERVERS-NAMETREE 2 +.SH NAME +Styxservers: nametree \- +hierarchical name storage for use with Styxservers. +.SH SYNOPSIS +.EX +include "sys.m"; +include "styx.m"; +include "styxservers.m"; +nametree := load Nametree Nametree->PATH; + Tree: import nametree; + +Tree: adt { + create: fn(t: self ref Tree, parentpath: big, d: Sys->Dir): string; + remove: fn(t: self ref Tree, path: big): string; + wstat: fn(t: self ref Tree, path: big, d: Sys->Dir); + quit: fn(t: self ref Tree); +}; +init: fn(); +start: fn(): (ref Tree, chan of ref Styxservers->Navop); +.EE +.SH DESCRIPTION +.B Nametree +provides the storage for a hierarchical namespace +to be used by +.IR styxservers (2). +After the module is loaded, the +.B init +function should be called to +initialise the module's internal variables. +.B Start +spawns a new +.B nametree +process; it returns a tuple, say +.RI ( tree ,\ c ), +where c is a channel that can be used to create +an instance of +.BR Styxservers->Navigator , +to access files inside +.BR nametree , +and +.I tree +is an adt that allows creation and removal of those files. +On failure, these functions return a string describing +the error. +.PP +Note that the full set of operations on +.B Nametree +(i.e. stat, walk, readdir, wstate, create and remove), +is only available in conjunction with +.BR Styxserver 's +.B Navigator +interface. +Files in the name space are ultimately identified by a 64-bit +.I path +value, which forms the path component of the file's Qid. +(See +.IR intro (5) +for a description of the system's interpretation of Qids.) +.PP +The +.B Tree +operations +are: +.TP 10 +.IB t .create(\fIparentpath\fP,\ \fId\fP) +Create a new file or directory. +.I D +gives the directory information that will be stored +for the file, including its own path value, +given by +.IB d .qid.path . +If the file referenced by +.I parentpath +does not exist, creation will not be allowed, +other than in the special case when +.IB d .qid.path +is equal to +.IR parentpath , +in which case it is assumed to be a root directory +and may be created. This potentially allows a single +.B Nametree +instance to hold many distinct directory hierarchies. +Note that no attempt is made to ensure that +.I parentpath +refers to a directory; the check is assumed to have +been made previously. +When a hierarchy is traversed, +.B Nametree +interprets the name +.RB ` .. ' +itself as `parent directory', and that name should not be created explicitly. +.TP +.IB t .remove(\fIpath\fP) +Remove the file referred to by +.IR path , +and all its descendants. +.TP +.IB t .wstat(\fIpath\fP,\ \fId\fP) +Change the directory information held on file +.IR path . +The Qid path itself cannot be changed by +.IR d . +.TP +.IB t .quit() +Shut down the +.B nametree +process. +.SH EXAMPLE +Here is a complete example that uses +.B Nametree +in conjunction with +.B Styxservers +in order to serve two files +.B data +and +.BR ctl " ..." +and do nothing with them: +.EX +implement Tst; +include "sys.m"; + sys: Sys; +include "draw.m"; +include "styx.m"; +include "styxservers.m"; + styxservers: Styxservers; + Styxserver, Navigator: import styxservers; + nametree: Nametree; + Tree: import nametree; + +Tst: module +{ + init: fn(nil: ref Draw->Context, argv: list of string); +}; + +Qroot, Qctl, Qdata: con big iota; # paths +init(nil: ref Draw->Context, args: list of string) +{ + sys = load Sys Sys->PATH; + styx := load Styx Styx->PATH; + styx->init(); + styxservers = load Styxservers Styxservers->PATH; + styxservers->init(styx); + nametree = load Nametree Nametree->PATH; + nametree->init(); + sys->pctl(Sys->FORKNS, nil); + (tree, treeop) := nametree->start(); + tree.create(Qroot, dir(".", 8r555|Sys->DMDIR, Qroot)); + tree.create(Qroot, dir("ctl", 8r666, Qctl)); + tree.create(Qroot, dir("data", 8r444, Qdata)); + (tchan, srv) := Styxserver.new(sys->fildes(0), + Navigator.new(treeop), Qroot); + while((gm := <-tchan) != nil) { + # normally a pick on gm would act on + # Tmsg.Read and Tmsg.Write at least + srv.default(gm); + } + tree.quit(); +} + +dir(name: string, perm: int, qid: big): Sys->Dir +{ + d := sys->zerodir; + d.name = name; + d.uid = "me"; + d.gid = "me"; + d.qid.path = qid; + if (perm & Sys->DMDIR) + d.qid.qtype = Sys->QTDIR; + else + d.qid.qtype = Sys->QTFILE; + d.mode = perm; + return d; +} +.EE +.SH SOURCE +.B /appl/lib/nametree.b +.SH SEE ALSO +.IR styxservers (2), +.IR intro (5) |