diff options
Diffstat (limited to 'appl/alphabet/fs/walk.b')
| -rw-r--r-- | appl/alphabet/fs/walk.b | 242 |
1 files changed, 242 insertions, 0 deletions
diff --git a/appl/alphabet/fs/walk.b b/appl/alphabet/fs/walk.b new file mode 100644 index 00000000..d99d0e9f --- /dev/null +++ b/appl/alphabet/fs/walk.b @@ -0,0 +1,242 @@ +implement Walk, Fsmodule; +include "sys.m"; + sys: Sys; +include "readdir.m"; + readdir: Readdir; +include "draw.m"; +include "sh.m"; +include "alphabet/reports.m"; + reports: Reports; + Report, quit, report: import reports; +include "alphabet/fs.m"; + fs: Fs; + Value: import fs; + Fschan, Fsdata, Entrychan, Entry, + Gatechan, Gatequery, Nilentry, Option, + Next, Down, Skip, Quit: import Fs; + +Walk: module {}; + +Loopcheck: adt { + a: array of list of ref Sys->Dir; + + new: fn(): ref Loopcheck; + enter: fn(l: self ref Loopcheck, d: ref Sys->Dir): int; + leave: fn(l: self ref Loopcheck, d: ref Sys->Dir); +}; + +types(): string +{ + return "xs-bs"; +} + +badmod(p: string) +{ + sys->fprint(sys->fildes(2), "fs: walk: cannot load %s: %r\n", p); + raise "fail:bad module"; +} + +init() +{ + sys = load Sys Sys->PATH; + fs = load Fs Fs->PATH; + if(fs == nil) + badmod(Fs->PATH); + fs->init(); + reports = load Reports Reports->PATH; + if(reports == nil) + badmod(Reports->PATH); + readdir = load Readdir Readdir->PATH; + if(readdir == nil) + badmod(Readdir->PATH); +} + +run(nil: ref Draw->Context, report: ref Report, + nil: list of Option, args: list of ref Value): ref Value +{ + path := (hd args).s().i; + (ok, d) := sys->stat(path); + if(ok== -1){ + sys->fprint(sys->fildes(2), "fs: walk: cannot stat %q: %r\n", path); + return nil; + } + if((d.mode & Sys->DMDIR) == 0){ + # XXX could produce an fs containing just the single file. + # would have to split the path though. + sys->fprint(sys->fildes(2), "fs: walk: %q is not a directory\n", path); + return nil; + } + sync := chan of int; + c := chan of (Fsdata, chan of int); + spawn fswalkproc(sync, path, c, Sys->ATOMICIO, report.start("walk")); + <-sync; + return ref Value.Vx(c); +} + +# XXX need to avoid loops in the filesystem... +fswalkproc(sync: chan of int, path: string, c: Fschan, blocksize: int, errorc: chan of string) +{ + sys->pctl(Sys->FORKNS, nil); + sync <-= 1; + # XXX could allow a single root file? + if(sys->chdir(path) == -1){ + report(errorc, sys->sprint("cannot cd to %q: %r", path)); + fs->sendnulldir(c); + quit(errorc); + } + (ok, d) := sys->stat("."); + if(ok == -1){ + report(errorc, sys->sprint("cannot stat %q: %r", path)); + fs->sendnulldir(c); + quit(errorc); + } + d.name = path; + reply := chan of int; + c <-= ((ref d, nil), reply); + if(<-reply == Down){ + loopcheck := Loopcheck.new(); + loopcheck.enter(ref d); + if(path[len path - 1] != '/') + path[len path] = '/'; + fswalkdir(path, c, blocksize, loopcheck, errorc); + c <-= ((nil, nil), reply); + <-reply; + } + quit(errorc); +} + +fswalkdir(path: string, c: Fschan, blocksize: int, loopcheck: ref Loopcheck, errorc: chan of string) +{ + reply := chan of int; + (a, n) := readdir->init(".", Readdir->NAME|Readdir->COMPACT); + if(n == -1){ + report(errorc, sys->sprint("cannot readdir %q: %r", path)); + return; + } + for(i := 0; i < n; i++) + if(a[i].mode & Sys->DMDIR) + if(loopcheck.enter(a[i]) == 0) + a[i].dtype = ~0; +directory: + for(i = 0; i < n; i++){ + if(a[i].mode & Sys->DMDIR){ + d := a[i]; + if(d.dtype == ~0){ + report(errorc, sys->sprint("filesystem loop at %#q", path + d.name)); + continue; + } + if(sys->chdir("./" + d.name) == -1){ + report(errorc, sys->sprint("cannot cd to %#q: %r", path + a[i].name)); + continue; + } + c <-= ((d, nil), reply); + case <-reply { + Quit => + quit(errorc); + Down => + fswalkdir(path + a[i].name + "/", c, blocksize, loopcheck, errorc); + c <-= ((nil, nil), reply); + if(<-reply == Quit) + quit(errorc); + Skip => + sys->chdir(".."); + i++; + break directory; + Next => + break; + } + if(sys->chdir("..") == -1) # XXX what should we do if this fails? + report(errorc, sys->sprint("failed to cd .. from %#q: %r\n", path + a[i].name)); + + } else { + if(fswalkfile(path, a[i], c, blocksize, errorc) == Skip) + break directory; + } + } + for(i = n - 1; i >= 0; i--) + if(a[i].mode & Sys->DMDIR && a[i].dtype != ~0) + loopcheck.leave(a[i]); +} + +fswalkfile(path: string, d: ref Sys->Dir, c: Fschan, blocksize: int, errorc: chan of string): int +{ + reply := chan of int; + fd := sys->open(d.name, Sys->OREAD); + if(fd == nil){ + report(errorc, sys->sprint("cannot open %q: %r", path+d.name)); + return Next; + } + c <-= ((d, nil), reply); + case <-reply { + Quit => + quit(errorc); + Skip => + return Skip; + Next => + return Next; + Down => + break; + } + length := d.length; + for(n := big 0; n < length; ){ + nr := blocksize; + if(n + big blocksize > length) + nr = int (length - n); + buf := array[nr] of byte; + nr = sys->read(fd, buf, nr); + if(nr <= 0){ + if(nr < 0) + report(errorc, sys->sprint("error reading %q: %r", path + d.name)); + else + report(errorc, sys->sprint("%q is shorter than expected (%bd/%bd)", + path + d.name, n, length)); + break; + }else if(nr < len buf) + buf = buf[0:nr]; + c <-= ((nil, buf), reply); + case <-reply { + Quit => + quit(errorc); + Skip => + return Next; + } + n += big nr; + } + c <-= ((nil, nil), reply); + if(<-reply == Quit) + quit(errorc); + return Next; +} + +HASHSIZE: con 32; + +issamedir(d0, d1: ref Sys->Dir): int +{ + (q0, q1) := (d0.qid, d1.qid); + return q0.path == q1.path && + q0.qtype == q1.qtype && + d0.dtype == d1.dtype && + d0.dev == d1.dev; +} + +Loopcheck.new(): ref Loopcheck +{ + return ref Loopcheck(array[HASHSIZE] of list of ref Sys->Dir); +} + +# XXX we're assuming no-one modifies the values in d behind our back... +Loopcheck.enter(l: self ref Loopcheck, d: ref Sys->Dir): int +{ + slot := int d.qid.path & (HASHSIZE-1); + for(ll := l.a[slot]; ll != nil; ll = tl ll) + if(issamedir(d, hd ll)) + return 0; + l.a[slot] = d :: l.a[slot]; + return 1; +} + +Loopcheck.leave(l: self ref Loopcheck, d: ref Sys->Dir) +{ + slot := int d.qid.path & (HASHSIZE-1); + l.a[slot] = tl l.a[slot]; +} |