diff options
Diffstat (limited to 'appl/cmd/gettar.b')
| -rw-r--r-- | appl/cmd/gettar.b | 248 |
1 files changed, 248 insertions, 0 deletions
diff --git a/appl/cmd/gettar.b b/appl/cmd/gettar.b new file mode 100644 index 00000000..4429ab24 --- /dev/null +++ b/appl/cmd/gettar.b @@ -0,0 +1,248 @@ +implement Gettar; + +include "sys.m"; + sys: Sys; + print, sprint, fprint: import sys; + stdin, stderr: ref sys->FD; + +include "draw.m"; + +include "arg.m"; + +TBLOCK: con 512; # tar logical blocksize + +Header: adt{ + name: string; + size: int; + mode: int; + mtime: int; + skip: int; +}; + +Gettar: module +{ + init: fn(nil: ref Draw->Context, nil: list of string); +}; + +error(mess: string) +{ + fprint(stderr,"gettar: %s\n",mess); + raise "fail:error"; +} + +verbose := 0; +NBLOCK: con 20; # traditional blocking factor for efficient read +tarbuf := array[NBLOCK*TBLOCK] of byte; # static buffer +nblock := NBLOCK; # how many blocks of data are in tarbuf +recno := NBLOCK; # how many blocks in tarbuf have been consumed + +getblock(): array of byte +{ + if(recno>=nblock){ + i := sys->read(stdin,tarbuf,TBLOCK*NBLOCK); + if(i==0) + return nil; + if(i<0) + error(sys->sprint("read error: %r")); + if(i%TBLOCK!=0) + error("blocksize error"); + nblock = i/TBLOCK; + recno = 0; + } + recno++; + return tarbuf[(recno-1)*TBLOCK:recno*TBLOCK]; +} + + +octal(b:array of byte): int +{ + sum := 0; + for(i:=0; i<len b; i++){ + bi := int b[i]; + if(bi==' ') continue; + if(bi==0) break; + sum = 8*sum + bi-'0'; + } + return sum; +} + +nullterm(b:array of byte): string +{ + for(i:=0; i<len b; i++) + if(b[i]==byte 0) break; + return string b[0:i]; +} + +getdir(): ref Header +{ + dblock := getblock(); + if(len dblock==0) + return nil; + if(dblock[0]==byte 0) + return nil; + + name := nullterm(dblock[0:100]); + if(int dblock[345]!=0) + name = nullterm(dblock[345:500])+"/"+name; + if(!absolute){ + if(name[0] == '#') + name = "./"+name; + else if(name[0] == '/') + name = "."+name; + } + + magic := string(dblock[257:262]); + if(magic[0]!=0 && magic!="ustar") + error("bad magic "+name); + chksum := octal(dblock[148:156]); + for(ci:=148; ci<156; ci++) + dblock[ci] = byte ' '; + for(i:=0; i<TBLOCK; i++) + chksum -= int dblock[i]; + if(chksum!=0) + error("directory checksum error "+name); + + skip := 1; + size := 0; + mode := 0; + mtime := 0; + case int dblock[156]{ + '0' or '7' or 0 => + skip = 0; + size = octal(dblock[124:136]); + mode = 8r777 & octal(dblock[100: 108]); + mtime = octal(dblock[136:148]); + '1' => + fprint(stderr,"gettar: skipping link %s -> %s\n",name,string(dblock[157:257])); + '2' or 's' => + fprint(stderr,"gettar: skipping symlink %s\n",name); + '3' or '4' or '6' => + fprint(stderr,"gettar: skipping special file %s\n",name); + '5' => + if(name[(len name)-1]=='/') + checkdir(name+"."); + else + checkdir(name+"/."); + * => + error(sprint("unrecognized typeflag %d for %s",int dblock[156],name)); + } + return ref Header(name, size, mode, mtime, skip); +} + +keep := 0; +absolute := 0; + +init(nil: ref Draw->Context, args: list of string) +{ + sys = load Sys Sys->PATH; + stdin = sys->fildes(0); + stderr = sys->fildes(2); + ofile: ref sys->FD; + + arg := load Arg Arg->PATH; + arg->init(args); + arg->setusage("gettar [-kTRv] [file ...]"); + while((o := arg->opt()) != 0) + case o { + 'k' => keep = 1; + 'v' => verbose = 1; + 'R' => absolute = 1; + * => arg->usage(); + } + args = arg->argv(); + arg = nil; + + while((file := getdir())!=nil){ + if(!file.skip){ + if((args == nil || matched(file.name, args)) && !(keep && exists(file.name))){ + if(verbose) + sys->fprint(stderr, "%s\n", file.name); + checkdir(file.name); + ofile = sys->create(file.name, Sys->OWRITE, 8r666); + if(ofile==nil){ + fprint(stderr, "gettar: cannot create %s: %r\n",file.name); + file.skip = 1; + } + }else + file.skip = 1; + } + bytes := file.size; + blocks := (bytes+TBLOCK-1)/TBLOCK; + if(file.skip){ + for(; blocks>0; blocks--) + getblock(); + continue; + } + + for(; blocks>0; blocks--){ + buf := getblock(); + nwrite := bytes; + if(nwrite>TBLOCK) + nwrite = TBLOCK; + if(sys->write(ofile,buf,nwrite)!=nwrite) + error(sprint("write error for %s: %r",file.name)); + bytes -= nwrite; + } + ofile = nil; + stat := sys->nulldir; + stat.mode = file.mode; + stat.mtime = file.mtime; + rc := sys->wstat(file.name,stat); + if(rc<0){ + # try just the mode + stat.mtime = ~0; + rc = sys->wstat(file.name, stat); + if(rc < 0) + fprint(stderr,"gettar: cannot set mode/mtime %s %#o %ud: %r\n",file.name, file.mode, file.mtime); + } + } +} + +checkdir(name: string) +{ + (nc,compl) := sys->tokenize(name,"/"); + path := ""; + while(compl!=nil){ + comp := hd compl; + if(comp=="..") + error(".. pathnames forbidden"); + if(nc>1){ + if(path=="") + path = comp; + else + path += "/"+comp; + (rc,stat) := sys->stat(path); + if(rc<0){ + fd := sys->create(path,Sys->OREAD,Sys->DMDIR+8r777); + if(fd==nil) + error(sprint("cannot mkdir %s: %r",path)); + fd = nil; + }else if(stat.mode&Sys->DMDIR==0) + error(sprint("found non-directory at %s",path)); + } + nc--; compl = tl compl; + } +} + +exists(path: string): int +{ + return sys->stat(path).t0 >= 0; +} + +matched(n: string, names: list of string): int +{ + for(; names != nil; names = tl names){ + p := hd names; + if(prefix(p, n)) + return 1; + } + return 0; +} + +prefix(p: string, s: string): int +{ + l := len p; + if(l > len s) + return 0; + return p == s[0:l] && (l == len s || s[l] == '/'); +} |