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1 // goredo -- djb's redo implementation on pure Go
2 // Copyright (C) 2020-2024 Sergey Matveev <stargrave@stargrave.org>
3 //
4 // This program is free software: you can redistribute it and/or modify
5 // it under the terms of the GNU General Public License as published by
6 // the Free Software Foundation, version 3 of the License.
7 //
8 // This program is distributed in the hope that it will be useful,
9 // but WITHOUT ANY WARRANTY; without even the implied warranty of
10 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
11 // GNU General Public License for more details.
12 //
13 // You should have received a copy of the GNU General Public License
14 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
15
16 // Targets runner
17
18 package main
19
20 import (
21         "bufio"
22         "crypto/rand"
23         "encoding/hex"
24         "errors"
25         "flag"
26         "fmt"
27         "io"
28         "io/fs"
29         "log"
30         "os"
31         "os/exec"
32         "path"
33         "strconv"
34         "strings"
35         "sync"
36         "syscall"
37         "time"
38
39         "go.cypherpunks.ru/recfile"
40         "go.cypherpunks.ru/tai64n/v2"
41         "golang.org/x/sys/unix"
42 )
43
44 const (
45         EnvDepFd        = "REDO_DEP_FD"
46         EnvDirPrefix    = "REDO_DIRPREFIX"
47         EnvDepCwd       = "REDO_DEP_CWD"
48         EnvBuildUUID    = "REDO_BUILD_UUID"
49         EnvStderrPrefix = "REDO_STDERR_PREFIX"
50         EnvTrace        = "REDO_TRACE"
51         EnvStderrKeep   = "REDO_LOGS"
52         EnvStderrSilent = "REDO_SILENT"
53         EnvNoSync       = "REDO_NO_SYNC"
54         EnvStopIfMod    = "REDO_STOP_IF_MODIFIED"
55
56         RedoDir      = ".redo"
57         LockSuffix   = ".lock"
58         DepSuffix    = ".dep"
59         TmpPrefix    = ".redo."
60         LogSuffix    = ".log"
61         LogRecSuffix = ".log-rec"
62 )
63
64 var (
65         NoSync       = false
66         StderrKeep   = false
67         StderrSilent = false
68         StderrPrefix string
69         StopIfMod    = false
70         Jobs         sync.WaitGroup
71
72         flagTrace          *bool
73         flagTraceAll       *bool
74         flagStderrKeep     *bool
75         flagStderrSilent   *bool
76         flagForcedIfchange *bool
77
78         TracedAll bool
79
80         RunningProcs  = map[int]*os.Process{}
81         RunningProcsM sync.Mutex
82
83         Err1WasTouched = errors.New("$1 was explicitly touched")
84 )
85
86 func init() {
87         cmdName := CmdName()
88         if !(cmdName == CmdNameRedo || cmdName == CmdNameRedoIfchange) {
89                 return
90         }
91         flagTrace = flag.Bool("x", false, "trace (sh -x) current targets")
92         flagTraceAll = flag.Bool("xx", false,
93                 fmt.Sprintf("trace (sh -x) all targets (%s=1)", EnvTrace))
94         flagStderrKeep = flag.Bool("k", false,
95                 fmt.Sprintf("keep job's stderr (%s=1)", EnvStderrKeep))
96         flagStderrSilent = flag.Bool("s", false,
97                 fmt.Sprintf("silent, do not print job's stderr (%s=1)", EnvStderrSilent))
98         flagForcedIfchange = flag.Bool("f", false, "forced redo-ifchange")
99 }
100
101 type RunError struct {
102         Tgt      *Tgt
103         DoFile   string
104         Started  *time.Time
105         Finished *time.Time
106         Err      error
107 }
108
109 func (e *RunError) Name() string {
110         var name string
111         if e.DoFile == "" {
112                 name = e.Tgt.rel
113         } else {
114                 name = fmt.Sprintf("%s (%s)", e.Tgt, e.DoFile)
115         }
116         if e.Finished == nil {
117                 return name
118         }
119         return fmt.Sprintf("%s (%.3fs)", name, e.Finished.Sub(*e.Started).Seconds())
120 }
121
122 func (e RunError) Error() string {
123         return fmt.Sprintf("%s: %s", e.Name(), e.Err)
124 }
125
126 func mkdirs(pth string) error {
127         if FileExists(pth) {
128                 return nil
129         }
130         return os.MkdirAll(pth, os.FileMode(0777))
131 }
132
133 func isModified(dep *Dep, tgt *Tgt) (
134         modified bool, ourInode *Inode, hshPrev Hash, err error,
135 ) {
136         if dep == nil {
137                 return
138         }
139         for _, ifchange := range dep.ifchanges {
140                 if ifchange.tgt.a != tgt.a {
141                         continue
142                 }
143                 ourInode, err = inodeFromFileByPath(tgt.a)
144                 if err != nil {
145                         if os.IsNotExist(err) {
146                                 err = nil
147                                 return
148                         }
149                         err = ErrLine(err)
150                         return
151                 }
152                 hshPrev = ifchange.Hash()
153                 modified = !ourInode.Equals(ifchange.Inode())
154                 break
155         }
156         return
157 }
158
159 func syncDir(dir string) error {
160         fd, err := os.Open(dir)
161         if err != nil {
162                 return err
163         }
164         err = fd.Sync()
165         fd.Close()
166         return err
167 }
168
169 func runScript(tgt *Tgt, errs chan error, forced, traced bool) error {
170         tgtH, tgtT := pathSplit(tgt.a)
171         redoDir := path.Join(tgtH, RedoDir)
172         if err := mkdirs(redoDir); err != nil {
173                 return TgtError{tgt, ErrLine(err)}
174         }
175
176         shCtx := fmt.Sprintf("sh: %s: cwd:%s", tgt, tgtH)
177         jsToken := jsAcquire(shCtx)
178         jsNeedsRelease := true
179         defer func() {
180                 if jsNeedsRelease {
181                         jsRelease(shCtx, jsToken)
182                 }
183         }()
184
185         // Acquire lock
186         fdLock, err := os.OpenFile(
187                 path.Join(redoDir, tgtT+LockSuffix),
188                 os.O_WRONLY|os.O_TRUNC|os.O_CREATE,
189                 os.FileMode(0666),
190         )
191         if err != nil {
192                 return TgtError{tgt, ErrLine(err)}
193         }
194         flock := unix.Flock_t{
195                 Type:   unix.F_WRLCK,
196                 Whence: io.SeekStart,
197         }
198         lockRelease := func() {
199                 tracef(CLock, "LOCK_UN: %s", fdLock.Name())
200                 flock.Type = unix.F_UNLCK
201                 if err := unix.FcntlFlock(fdLock.Fd(), unix.F_SETLK, &flock); err != nil {
202                         log.Fatalln(err, fdLock.Name())
203                 }
204                 fdLock.Close()
205         }
206         tracef(CLock, "LOCK_NB: %s", fdLock.Name())
207
208         // Waiting for job completion, already taken by someone else
209         if err = unix.FcntlFlock(fdLock.Fd(), unix.F_SETLK, &flock); err != nil {
210                 if uintptr(err.(syscall.Errno)) != uintptr(unix.EAGAIN) {
211                         fdLock.Close()
212                         return TgtError{tgt, ErrLine(err)}
213                 }
214                 Jobs.Add(1)
215                 if err = unix.FcntlFlock(fdLock.Fd(), unix.F_GETLK, &flock); err != nil {
216                         log.Fatalln(err, fdLock.Name())
217                 }
218                 tracef(CDebug, "waiting: %s (pid=%d)", tgt, flock.Pid)
219                 if FdStatus != nil {
220                         if _, err = FdStatus.Write([]byte{StatusWait}); err != nil {
221                                 log.Fatal(err)
222                         }
223                 }
224                 go func() {
225                         defer Jobs.Done()
226                         tracef(CLock, "LOCK_EX: %s", fdLock.Name())
227                 LockAgain:
228                         if err := unix.FcntlFlock(fdLock.Fd(), unix.F_SETLKW, &flock); err != nil {
229                                 if errors.Is(err, unix.EDEADLK) {
230                                         time.Sleep(10 * time.Millisecond)
231                                         goto LockAgain
232                                 }
233                                 log.Fatalln(err, fdLock.Name())
234                         }
235                         lockRelease()
236                         tracef(CDebug, "waiting done: %s", tgt)
237                         if FdStatus != nil {
238                                 if _, err = FdStatus.Write([]byte{StatusWaited}); err != nil {
239                                         log.Fatal(err)
240                                 }
241                         }
242                         build, err := depBuildRead(tgt.dep)
243                         if err == nil {
244                                 if build != BuildUUID {
245                                         err = errors.New("was not built: build differs")
246                                 }
247                         } else {
248                                 if errors.Is(err, fs.ErrNotExist) {
249                                         err = errors.New("was not built: no .dep")
250                                 }
251                         }
252                         if err != nil {
253                                 err = TgtError{tgt, err}
254                         }
255                         errs <- err
256                 }()
257                 return nil
258         }
259
260         // It scans the whole .dep file while searching for the single target,
261         // but that one is always located at the very end
262         dep, err := depRead(tgt)
263         if err != nil {
264                 if errors.Is(err, fs.ErrNotExist) {
265                         err = nil
266                 } else {
267                         lockRelease()
268                         return TgtError{tgt, ErrLine(err)}
269                 }
270         }
271
272         // Check if it was already built in parallel
273         if !forced && dep != nil && dep.build == BuildUUID {
274                 lockRelease()
275                 errs <- nil
276                 return nil
277         }
278
279         // Check if target is not modified externally
280         modified, inodePrev, hshPrev, err := isModified(dep, tgt)
281         if err != nil {
282                 lockRelease()
283                 return TgtError{tgt, ErrLine(err)}
284         }
285         if modified {
286                 lockRelease()
287                 if StopIfMod {
288                         return fmt.Errorf("%s externally modified", tgt)
289                 }
290                 Jobs.Add(1)
291                 tracef(CWarn, "%s externally modified: not redoing", tgt)
292                 go func() {
293                         errs <- nil
294                         Jobs.Done()
295                 }()
296                 return nil
297         }
298         dep = nil
299
300         // Start preparing .dep
301         fdDep, err := tempfile(redoDir, tgtT+DepSuffix)
302         if err != nil {
303                 lockRelease()
304                 return TgtError{tgt, ErrLine(err)}
305         }
306         fdDepOpened := true
307         fdDepExists := true
308         fdDepW := bufio.NewWriter(fdDep)
309         cleanup := func() {
310                 lockRelease()
311                 if fdDepOpened {
312                         fdDep.Close()
313                 }
314                 if fdDepExists {
315                         os.Remove(fdDep.Name())
316                 }
317         }
318         if err = depBuildWrite(fdDepW, BuildUUID); err != nil {
319                 cleanup()
320                 return TgtError{tgt, ErrLine(err)}
321         }
322
323         var cwd string
324         var dirPrefix string
325         var doFile *Tgt
326         var doFileT string
327         basename := tgtT
328         runErr := RunError{Tgt: tgt}
329         // Determine basename and DIRPREFIX
330         {
331                 doFileRelPath, upLevels, err := findDo(fdDepW, fdDep.Name(), tgtH, tgtT)
332                 if err != nil {
333                         cleanup()
334                         return TgtError{tgt, ErrLine(err)}
335                 }
336                 if doFileRelPath == "" {
337                         cleanup()
338                         return TgtError{tgt, errors.New("no .do found")}
339                 }
340                 ents := strings.Split(tgtH, "/")
341                 ents = ents[len(ents)-upLevels:]
342                 dirPrefix = path.Join(ents...)
343                 ups := make([]string, 0, upLevels+2)
344                 ups = append(ups, tgtH)
345                 for i := 0; i < upLevels; i++ {
346                         ups = append(ups, "..")
347                 }
348                 ups = append(ups, doFileRelPath)
349                 cwd = path.Clean(path.Join(ups[:len(ups)-1]...))
350                 doFile = NewTgt(path.Join(ups...))
351                 doFileT = path.Base(doFile.a)
352                 if strings.HasPrefix(doFileT, "default.") {
353                         basename = basename[:len(basename)-(len(doFileT)-len("default.")-len(".do"))-1]
354                         runErr.DoFile = doFile.rel
355                 }
356         }
357
358         if err = depWrite(fdDepW, fdDep.Name(), tgtH, doFile, ""); err != nil {
359                 cleanup()
360                 return TgtError{tgt, ErrLine(err)}
361         }
362         if err = fdDepW.Flush(); err != nil {
363                 cleanup()
364                 return TgtError{tgt, ErrLine(err)}
365         }
366         fdDep.Close()
367         fdDepOpened = false
368         tracef(CWait, "%s", runErr.Name())
369
370         // Prepare command line
371         var cmdName string
372         var args []string
373         if err = unix.Access(doFile.rel, unix.X_OK); err == nil {
374                 cmdName = doFile.a
375                 args = make([]string, 0, 3)
376         } else {
377                 cmdName = "/bin/sh"
378                 if traced || TracedAll {
379                         args = append(args, "-ex")
380                 } else {
381                         args = append(args, "-e")
382                 }
383                 args = append(args, doFileT)
384         }
385
386         // Temporary file for stdout
387         fdStdout, err := tempfile(tgtH, tgtT)
388         if err != nil {
389                 cleanup()
390                 return TgtError{tgt, ErrLine(err)}
391         }
392         fdStdout.Close()
393         tmpPath := fdStdout.Name() + ".3" // and for $3
394         tmpPathRel := mustRel(cwd, tmpPath)
395         args = append(
396                 args,
397                 path.Join(dirPrefix, tgtT),
398                 path.Join(dirPrefix, basename),
399                 tmpPathRel,
400         )
401         shCtx = fmt.Sprintf(
402                 "sh: %s: %s %s cwd:%s dirprefix:%s",
403                 tgt, cmdName, args, cwd, dirPrefix,
404         )
405
406         cmd := exec.Command(cmdName, args...)
407         cmd.Dir = cwd
408         // cmd.Stdin reads from /dev/null by default
409         cmd.Env = append(os.Environ(), fmt.Sprintf("%s=%d", EnvLevel, Level+1))
410         cmd.Env = append(cmd.Env, fmt.Sprintf("%s=%s", EnvDirPrefix, dirPrefix))
411         cmd.Env = append(cmd.Env, fmt.Sprintf("%s=%s", EnvBuildUUID, BuildUUID))
412
413         childStderrPrefixRaw := make([]byte, 8)
414         if _, err = io.ReadFull(rand.Reader, childStderrPrefixRaw); err != nil {
415                 panic(err)
416         }
417         childStderrPrefix := hex.EncodeToString(childStderrPrefixRaw)
418         cmd.Env = append(cmd.Env, fmt.Sprintf(
419                 "%s=%s", EnvStderrPrefix, childStderrPrefix,
420         ))
421
422         fdNum := 0
423         cmd.ExtraFiles = append(cmd.ExtraFiles, FdOODTgts)
424         cmd.Env = append(cmd.Env, fmt.Sprintf("%s=%d", EnvOODTgtsFd, 3+fdNum))
425         fdNum++
426         cmd.ExtraFiles = append(cmd.ExtraFiles, FdOODTgtsLock)
427         cmd.Env = append(cmd.Env, fmt.Sprintf("%s=%d", EnvOODTgtsLockFd, 3+fdNum))
428         fdNum++
429
430         if FdStatus == nil {
431                 cmd.Env = append(cmd.Env, fmt.Sprintf("%s=NO", EnvStatusFd))
432         } else {
433                 cmd.ExtraFiles = append(cmd.ExtraFiles, FdStatus)
434                 cmd.Env = append(cmd.Env, fmt.Sprintf("%s=%d", EnvStatusFd, 3+fdNum))
435                 fdNum++
436         }
437
438         // Preparing stderr
439         var fdStderr *os.File
440         if StderrKeep {
441                 fdStderr, err = os.OpenFile(
442                         path.Join(redoDir, tgtT+LogSuffix),
443                         os.O_WRONLY|os.O_CREATE|os.O_TRUNC,
444                         os.FileMode(0666),
445                 )
446                 if err != nil {
447                         cleanup()
448                         return TgtError{tgt, ErrLine(err)}
449                 }
450         }
451         tracef(CDebug, "%s", shCtx)
452
453         jsNeedsRelease = false
454         Jobs.Add(1)
455         go func() {
456                 if JSR == nil {
457                         // infinite jobs
458                         cmd.Env = append(cmd.Env, fmt.Sprintf("%s=NO", EnvJobs))
459                 } else {
460                         cmd.ExtraFiles = append(cmd.ExtraFiles, JSR)
461                         cmd.ExtraFiles = append(cmd.ExtraFiles, JSW)
462                         makeFlags := fmt.Sprintf(
463                                 "%s %s%d,%d", MakeFlags, MakeJSArg, 3+fdNum+0, 3+fdNum+1,
464                         )
465                         makeFlags = strings.Trim(makeFlags, " ")
466                         cmd.Env = append(cmd.Env, fmt.Sprintf("%s=%s", MakeFlagsName, makeFlags))
467                         fdNum += 2
468                         cmd.Env = append(cmd.Env, fmt.Sprintf("%s=%d", EnvJSToken, jsToken))
469                 }
470
471                 if FdStatus != nil {
472                         if _, err = FdStatus.Write([]byte{StatusRun}); err != nil {
473                                 log.Fatal(err)
474                         }
475                 }
476
477                 defer jsRelease(shCtx, jsToken)
478
479                 var finished time.Time
480                 var exitErr *exec.ExitError
481                 started := time.Now()
482                 runErr.Started = &started
483                 fdStdout, err = os.OpenFile(fdStdout.Name(), os.O_RDWR, os.FileMode(0666))
484                 if err != nil {
485                         if fdStderr != nil {
486                                 fdStderr.Close()
487                         }
488                         runErr.Err = err
489                         errs <- runErr
490                         return
491                 }
492                 cmd.Stdout = fdStdout
493                 fdDep, err = os.OpenFile(fdDep.Name(), os.O_WRONLY|os.O_APPEND, os.FileMode(0666))
494                 if err != nil {
495                         if fdStderr != nil {
496                                 fdStderr.Close()
497                         }
498                         fdStdout.Close()
499                         runErr.Err = err
500                         errs <- runErr
501                         return
502                 }
503                 fdDepOpened = true
504                 fdDepW.Reset(fdDep)
505                 cmd.ExtraFiles = append(cmd.ExtraFiles, fdDep)
506                 cmd.Env = append(cmd.Env, fmt.Sprintf("%s=%d", EnvDepFd, 3+fdNum))
507                 fdNum++
508                 cmd.Env = append(cmd.Env, fmt.Sprintf("%s=%s", EnvDepCwd, cwd))
509
510                 defer func() {
511                         if fdDepOpened {
512                                 fdDep.Close()
513                         }
514                         fdStdout.Close()
515                         if fdStderr != nil {
516                                 fdStderr.Close()
517                                 logRecPath := path.Join(redoDir, tgtT+LogRecSuffix)
518                                 if fdStderr, err = os.OpenFile(
519                                         logRecPath,
520                                         os.O_WRONLY|os.O_CREATE|os.O_TRUNC,
521                                         os.FileMode(0666),
522                                 ); err == nil {
523                                         fields := []recfile.Field{
524                                                 {Name: "Build", Value: BuildUUID.String()},
525                                                 {Name: "PPID", Value: strconv.Itoa(os.Getpid())},
526                                                 {Name: "Cwd", Value: cwd},
527                                         }
528                                         if cmd.Process != nil {
529                                                 fields = append(fields, recfile.Field{
530                                                         Name: "PID", Value: strconv.Itoa(cmd.Process.Pid),
531                                                 })
532                                         }
533                                         ts := new(tai64n.TAI64N)
534                                         ts.FromTime(started)
535                                         fields = append(fields,
536                                                 recfile.Field{Name: "Started", Value: tai64n.Encode(ts[:])},
537                                         )
538                                         ts.FromTime(finished)
539                                         fields = append(fields,
540                                                 recfile.Field{Name: "Finished", Value: tai64n.Encode(ts[:])})
541                                         fields = append(fields, recfile.Field{
542                                                 Name:  "Duration",
543                                                 Value: strconv.FormatInt(finished.Sub(started).Nanoseconds(), 10),
544                                         })
545                                         fields = append(fields, recfile.Field{Name: "Cmd", Value: cmdName})
546                                         for _, arg := range args {
547                                                 fields = append(fields, recfile.Field{Name: "Arg", Value: arg})
548                                         }
549                                         for _, env := range cmd.Env {
550                                                 fields = append(fields, recfile.Field{Name: "Env", Value: env})
551                                         }
552                                         if exitErr != nil {
553                                                 fields = append(fields, recfile.Field{
554                                                         Name:  "ExitCode",
555                                                         Value: strconv.Itoa(exitErr.ProcessState.ExitCode()),
556                                                 })
557                                         }
558
559                                         w := bufio.NewWriter(fdStderr)
560                                         if !fdDepExists {
561                                                 var ifchanges []string
562                                                 ifchanges, err = depReadOnlyIfchanges(tgt.dep)
563                                                 if err != nil {
564                                                         err = ErrLine(err)
565                                                         goto Err
566                                                 }
567                                                 for _, ifchange := range ifchanges {
568                                                         fields = append(fields, recfile.Field{
569                                                                 Name:  "Ifchange",
570                                                                 Value: ifchange,
571                                                         })
572                                                 }
573                                         }
574                                         _, err = recfile.NewWriter(w).WriteFields(fields...)
575                                         if err != nil {
576                                                 err = ErrLine(err)
577                                                 goto Err
578                                         }
579                                         err = ErrLine(w.Flush())
580                                 Err:
581                                         if err != nil {
582                                                 log.Print(err)
583                                                 os.Remove(logRecPath)
584                                         }
585                                         fdStderr.Close()
586                                 } else {
587                                         log.Println("can not open", logRecPath, ":", err)
588                                 }
589                         }
590                         lockRelease()
591                         if fdDepExists {
592                                 os.Remove(fdDep.Name())
593                         }
594                         os.Remove(fdStdout.Name())
595                         os.Remove(tmpPath)
596                         if FdStatus != nil {
597                                 if _, err = FdStatus.Write([]byte{StatusDone}); err != nil {
598                                         log.Fatal(err)
599                                 }
600                         }
601                         Jobs.Done()
602                 }()
603                 stderr, err := cmd.StderrPipe()
604                 if err != nil {
605                         runErr.Err = err
606                         errs <- runErr
607                         return
608                 }
609                 started = time.Now()
610                 err = cmd.Start()
611                 if err != nil {
612                         runErr.Err = err
613                         errs <- runErr
614                         return
615                 }
616                 RunningProcsM.Lock()
617                 RunningProcs[cmd.Process.Pid] = cmd.Process
618                 RunningProcsM.Unlock()
619                 pid := fmt.Sprintf("[%d]", cmd.Process.Pid)
620                 tracef(CDebug, "%s runs %s", tgt, pid)
621
622                 stderrTerm := make(chan struct{})
623                 go func() {
624                         scanner := bufio.NewScanner(stderr)
625                         var line string
626                         ts := new(tai64n.TAI64N)
627                         for scanner.Scan() {
628                                 line = scanner.Text()
629                                 if strings.HasPrefix(line, childStderrPrefix) {
630                                         line = line[len(childStderrPrefix):]
631                                         if StderrPrefix == "" {
632                                                 withPrependedTgt(line)
633                                         } else {
634                                                 stderrWrite(StderrPrefix + line + "\n")
635                                         }
636                                         continue
637                                 }
638                                 if fdStderr != nil {
639                                         ts.FromTime(time.Now())
640                                         fmt.Fprintln(fdStderr, tai64n.Encode(ts[:]), line)
641                                 }
642                                 if StderrSilent {
643                                         continue
644                                 }
645                                 if MyPID != 0 {
646                                         line = pid + " " + line
647                                 }
648                                 if StderrPrefix == "" {
649                                         withPrependedTgt("[" + tgt.rel + "]" + line)
650                                 } else {
651                                         stderrWrite(StderrPrefix + "[" + tgt.rel + "]" + line + "\n")
652                                 }
653                         }
654                         close(stderrTerm)
655                 }()
656
657                 // Wait for job completion
658                 <-stderrTerm
659                 err = cmd.Wait()
660                 RunningProcsM.Lock()
661                 delete(RunningProcs, cmd.Process.Pid)
662                 RunningProcsM.Unlock()
663                 finished = time.Now()
664                 runErr.Finished = &finished
665                 if err != nil {
666                         exitErr = err.(*exec.ExitError)
667                         runErr.Err = err
668                         errs <- runErr
669                         return
670                 }
671
672                 // Was $1 touched?
673                 if inode, err := inodeFromFileByPath(tgt.a); err == nil {
674                         if inodePrev == nil {
675                                 runErr.Err = Err1WasTouched
676                                 errs <- runErr
677                                 return
678                         }
679                         if !inode.Equals(inodePrev) {
680                                 runErr.Err = Err1WasTouched
681                                 errs <- runErr
682                                 return
683                         }
684                 }
685
686                 // Does it produce both stdout and tmp?
687                 fiStdout, err := os.Stat(fdStdout.Name())
688                 if err != nil {
689                         runErr.Err = ErrLine(err)
690                         errs <- runErr
691                         return
692                 }
693                 tmpExists := false
694                 _, err = os.Stat(tmpPath)
695                 if err == nil {
696                         if fiStdout.Size() > 0 {
697                                 runErr.Err = errors.New("created both tmp and stdout")
698                                 errs <- runErr
699                                 return
700                         }
701                         tmpExists = true
702                 } else if !errors.Is(err, fs.ErrNotExist) {
703                         runErr.Err = ErrLine(err)
704                         errs <- runErr
705                         return
706                 }
707
708                 // Determine what file we must process at last
709                 var fd *os.File
710                 var chmod fs.FileMode
711                 if tmpExists {
712                         fd, err = os.Open(tmpPath)
713                         if err != nil {
714                                 err = ErrLine(err)
715                                 goto Finish
716                         }
717                         defer fd.Close()
718                         if fi, rerr := fd.Stat(); rerr == nil {
719                                 chmod = fi.Mode()
720                         } else {
721                                 err = ErrLine(rerr)
722                                 goto Finish
723                         }
724                 } else if fiStdout.Size() > 0 {
725                         fd = fdStdout
726                 }
727
728                 // Do we need to ifcreate it, or ifchange with renaming?
729                 if fd == nil {
730                         os.Remove(tgt.a)
731                         err = ifcreate(fdDepW, fdDep.Name(), tgtT)
732                         if err != nil {
733                                 err = ErrLine(err)
734                                 goto Finish
735                         }
736                 } else {
737                         var hsh Hash
738                         if hshPrev != "" {
739                                 _, err = fd.Seek(0, io.SeekStart)
740                                 if err != nil {
741                                         err = ErrLine(err)
742                                         goto Finish
743                                 }
744                                 hsh, err = fileHash(fd)
745                                 if err != nil {
746                                         err = ErrLine(err)
747                                         goto Finish
748                                 }
749                                 if hsh == hshPrev {
750                                         tracef(CDebug, "%s has same hash, not renaming", tgt)
751                                         err = ErrLine(os.Remove(fd.Name()))
752                                         if err != nil {
753                                                 goto Finish
754                                         }
755                                         if chmod != 0 {
756                                                 err = ErrLine(os.Chmod(tgt.a, chmod))
757                                                 if err != nil {
758                                                         goto Finish
759                                                 }
760                                         }
761                                         err = ErrLine(os.Chtimes(tgt.a, finished, finished))
762                                         if err != nil {
763                                                 goto Finish
764                                         }
765                                         if !NoSync {
766                                                 err = ErrLine(syncDir(tgtH))
767                                                 if err != nil {
768                                                         goto Finish
769                                                 }
770                                         }
771                                         err = ErrLine(depWrite(fdDepW, fdDep.Name(), tgtH, tgt, hsh))
772                                         if err != nil {
773                                                 goto Finish
774                                         }
775                                         goto RecCommit
776                                 }
777                         }
778                         if !NoSync {
779                                 err = ErrLine(fd.Sync())
780                                 if err != nil {
781                                         goto Finish
782                                 }
783                         }
784                         err = ErrLine(os.Rename(fd.Name(), tgt.a))
785                         if err != nil {
786                                 goto Finish
787                         }
788                         if !NoSync {
789                                 err = ErrLine(syncDir(tgtH))
790                                 if err != nil {
791                                         goto Finish
792                                 }
793                         }
794                         err = ErrLine(depWrite(fdDepW, fdDep.Name(), tgtH, tgt, hsh))
795                         if err != nil {
796                                 goto Finish
797                         }
798                 }
799
800         RecCommit:
801                 // Commit .dep
802                 err = ErrLine(fdDepW.Flush())
803                 if err != nil {
804                         goto Finish
805                 }
806                 if !NoSync {
807                         err = ErrLine(fdDep.Sync())
808                         if err != nil {
809                                 goto Finish
810                         }
811                 }
812                 err = ErrLine(os.Rename(fdDep.Name(), tgt.dep))
813                 if err != nil {
814                         goto Finish
815                 }
816                 fdDepExists = false
817                 if !NoSync {
818                         err = ErrLine(syncDir(redoDir))
819                         if err != nil {
820                                 goto Finish
821                         }
822                 }
823                 fdDep.Close()
824                 fdDepOpened = false
825
826                 // Post-commit .dep sanitizing
827                 dep, err = depRead(tgt)
828                 if err == nil {
829                         ifchangeSeen := make(map[string]struct{}, len(dep.ifchanges))
830                         for _, ifchange := range dep.ifchanges {
831                                 ifchangeSeen[ifchange.tgt.a] = struct{}{}
832                         }
833                         for _, ifcreate := range dep.ifcreates {
834                                 if _, exists := ifchangeSeen[ifcreate.a]; exists {
835                                         tracef(CWarn, "simultaneous ifcreate and ifchange records: %s", tgt)
836                                 }
837                         }
838                 } else if errors.Is(err, fs.ErrNotExist) {
839                         err = nil
840                 } else {
841                         err = ErrLine(err)
842                         goto Finish
843                 }
844
845         Finish:
846                 runErr.Err = err
847                 errs <- runErr
848         }()
849         return nil
850 }
851
852 func isOkRun(err error) bool {
853         if err == nil {
854                 return true
855         }
856         var runErr RunError
857         if errors.As(err, &runErr) && runErr.Err == nil {
858                 tracef(CRedo, "%s", runErr.Name())
859                 return true
860         }
861         tracef(CErr, "%s", err)
862         return false
863 }