summary refs log tree commit diff
path: root/redo.c
blob: 8edf65717da2017f2f09db4367431264979c6fdd (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
/* An implementation of the redo build system
   in portable C with zero dependencies

   http://cr.yp.to/redo.html
   http://homepage.ntlworld.com/jonathan.deboynepollard/FGA/introduction-to-redo.html
   https://github.com/apenwarr/redo/blob/master/README.md
   http://news.dieweltistgarnichtso.net/bin/redo-sh.html

   To the extent possible under law,
   Christian Neukirchen <chneukirchen@gmail.com>
   has waived all copyright and related or neighboring rights to this work.

   http://creativecommons.org/publicdomain/zero/1.0/
*/

/*
##% cc -g -Os -Wall -Wextra -Wwrite-strings -o $STEM $FILE
*/

/*
current bugs:
  dependency-loop: unlimited recursion
    need locks

todo:
  test job server properly
*/

#include <sys/param.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>

#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
#include <poll.h>
#include <stdarg.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

// ---------------------------------------------------------------------------
// from musl/src/crypt/crypt_sha256.c

/* public domain sha256 implementation based on fips180-3 */

struct sha256 {
	uint64_t len;	 /* processed message length */
	uint32_t h[8];	 /* hash state */
	uint8_t buf[64]; /* message block buffer */
};

static uint32_t ror(uint32_t n, int k) { return (n >> k) | (n << (32-k)); }
#define Ch(x,y,z)  (z ^ (x & (y ^ z)))
#define Maj(x,y,z) ((x & y) | (z & (x | y)))
#define S0(x)	   (ror(x,2) ^ ror(x,13) ^ ror(x,22))
#define S1(x)	   (ror(x,6) ^ ror(x,11) ^ ror(x,25))
#define R0(x)	   (ror(x,7) ^ ror(x,18) ^ (x>>3))
#define R1(x)	   (ror(x,17) ^ ror(x,19) ^ (x>>10))

static const uint32_t K[64] = {
0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
};

static void processblock(struct sha256 *s, const uint8_t *buf)
{
	uint32_t W[64], t1, t2, a, b, c, d, e, f, g, h;
	int i;

	for (i = 0; i < 16; i++) {
		W[i] = (uint32_t)buf[4*i]<<24;
		W[i] |= (uint32_t)buf[4*i+1]<<16;
		W[i] |= (uint32_t)buf[4*i+2]<<8;
		W[i] |= buf[4*i+3];
	}
	for (; i < 64; i++)
		W[i] = R1(W[i-2]) + W[i-7] + R0(W[i-15]) + W[i-16];
	a = s->h[0];
	b = s->h[1];
	c = s->h[2];
	d = s->h[3];
	e = s->h[4];
	f = s->h[5];
	g = s->h[6];
	h = s->h[7];
	for (i = 0; i < 64; i++) {
		t1 = h + S1(e) + Ch(e,f,g) + K[i] + W[i];
		t2 = S0(a) + Maj(a,b,c);
		h = g;
		g = f;
		f = e;
		e = d + t1;
		d = c;
		c = b;
		b = a;
		a = t1 + t2;
	}
	s->h[0] += a;
	s->h[1] += b;
	s->h[2] += c;
	s->h[3] += d;
	s->h[4] += e;
	s->h[5] += f;
	s->h[6] += g;
	s->h[7] += h;
}

static void pad(struct sha256 *s)
{
	unsigned r = s->len % 64;

	s->buf[r++] = 0x80;
	if (r > 56) {
		memset(s->buf + r, 0, 64 - r);
		r = 0;
		processblock(s, s->buf);
	}
	memset(s->buf + r, 0, 56 - r);
	s->len *= 8;
	s->buf[56] = s->len >> 56;
	s->buf[57] = s->len >> 48;
	s->buf[58] = s->len >> 40;
	s->buf[59] = s->len >> 32;
	s->buf[60] = s->len >> 24;
	s->buf[61] = s->len >> 16;
	s->buf[62] = s->len >> 8;
	s->buf[63] = s->len;
	processblock(s, s->buf);
}

static void sha256_init(struct sha256 *s)
{
	s->len = 0;
	s->h[0] = 0x6a09e667;
	s->h[1] = 0xbb67ae85;
	s->h[2] = 0x3c6ef372;
	s->h[3] = 0xa54ff53a;
	s->h[4] = 0x510e527f;
	s->h[5] = 0x9b05688c;
	s->h[6] = 0x1f83d9ab;
	s->h[7] = 0x5be0cd19;
}

static void sha256_sum(struct sha256 *s, uint8_t *md)
{
	int i;

	pad(s);
	for (i = 0; i < 8; i++) {
		md[4*i] = s->h[i] >> 24;
		md[4*i+1] = s->h[i] >> 16;
		md[4*i+2] = s->h[i] >> 8;
		md[4*i+3] = s->h[i];
	}
}

static void sha256_update(struct sha256 *s, const void *m, unsigned long len)
{
	const uint8_t *p = m;
	unsigned r = s->len % 64;

	s->len += len;
	if (r) {
		if (len < 64 - r) {
			memcpy(s->buf + r, p, len);
			return;
		}
		memcpy(s->buf + r, p, 64 - r);
		len -= 64 - r;
		p += 64 - r;
		processblock(s, s->buf);
	}
	for (; len >= 64; len -= 64, p += 64)
		processblock(s, p);
	memcpy(s->buf, p, len);
}

// ----------------------------------------------------------------------

int dir_fd = -1;
int dep_fd = -1;
int poolwr_fd = -1;
int poolrd_fd = -1;
int level = -1;
int implicit_jobs = 1;
int kflag, jflag, xflag, fflag, sflag;

static void
redo_ifcreate(char *target)
{
	dprintf(dep_fd, "-%s\n", target);
}

static char *
check_dofile(const char *fmt, ...)
{
	static char dofile[PATH_MAX];

	va_list ap;
	va_start(ap, fmt);
	vsnprintf(dofile, sizeof dofile, fmt, ap);
	va_end(ap);

	if (access (dofile, F_OK) == 0) {
		return dofile;
	} else {
		redo_ifcreate(dofile);
		return 0;
	}
}

/*
dir/base.a.b
       will look for dir/base.a.b.do,
       dir/default.a.b.do, dir/default.b.do, dir/default.do,
       default.a.b.do, default.b.do, and default.do.

this function assumes no / in target
*/
static char *
find_dofile(char *target)
{
	char updir[PATH_MAX];
	char *u = updir;
	char *dofile, *s;
	struct stat st, ost;

	dofile = check_dofile("./%s.do", target);
	if (dofile)
		return dofile;

	*u++ = '.';
	*u++ = '/';
	*u = 0;

	st.st_dev = ost.st_dev = st.st_ino = ost.st_ino = 0;
	
	while (1) {
		ost = st;

		if (stat(updir, &st) < 0)
			return 0;
		if (ost.st_dev == st.st_dev && ost.st_ino == st.st_ino)
			break;	// reached root dir, .. = .

		s = target;
		while (*s) {
			if (*s++ == '.') {
				dofile = check_dofile("%sdefault.%s.do", updir, s);
				if (dofile)
					return dofile;
			}
		}

		dofile = check_dofile("%sdefault.do", updir);
		if (dofile)
			return dofile;

		*u++ = '.';
		*u++ = '.';
		*u++ = '/';
		*u = 0;
	}

	return 0;
}

static int
envfd(const char *name)
{
	long fd;

	char *s = getenv(name);
	if (!s)
		return -1;
	
	fd = strtol(s, 0, 10);
	if (fd < 0 || fd > 255)
		fd = -1;
	
	return fd;
}

static void
setenvfd(const char *name, int i)
{
	char buf[16];
	snprintf(buf, sizeof buf, "%d", i);
	setenv(name, buf, 1);
}

static char *
hashfile(int fd)
{
	static char hex[16] = "0123456789abcdef";
	static char asciihash[65];

	struct sha256 ctx;
	off_t off = 0;
	char buf[4096];
	char *a;
	unsigned char hash[32];
	int i;
	ssize_t r;

	sha256_init(&ctx);

	while ((r = pread(fd, buf, sizeof buf, off)) > 0) {
		sha256_update(&ctx, buf, r);
		off += r;
	}
	
	sha256_sum(&ctx, hash);
	
	for (i = 0, a = asciihash; i < 32; i++) {
		*a++ = hex[hash[i] / 16];
		*a++ = hex[hash[i] % 16];
	}
	*a = 0;

	return asciihash;
}

static char *
datefile(int fd)
{
	static char hexdate[17];
	struct stat st;

	fstat(fd, &st);
	snprintf(hexdate, sizeof hexdate, "%016" PRIx64, st.st_ctime);

	return hexdate;
}

static char *
targetchdir(char *target) {
	char *base = strrchr(target, '/');
	if (base) {
		int fd;
		*base = 0;
		fd = openat(dir_fd, target, O_RDONLY | O_DIRECTORY);
		if (fd < 0) {
			perror("openat dir");
			exit(111);
		}
		*base = '/';
		if (fchdir(fd) < 0) {
			perror("chdir");
			exit(111);
		}
		close(fd);
		return base+1;
	} else {
		fchdir(dir_fd);
		return target;
	}
}

static char *
targetdep(char *target) {
	static char buf[PATH_MAX];
	snprintf(buf, sizeof buf, ".dep.%s", target);
	return buf;
}

static char *
targetlock(char *target) {
	static char buf[PATH_MAX];
	snprintf(buf, sizeof buf, ".lock.%s", target);
	return buf;
}

static int
sourcefile(char *target)
{
	target = targetchdir(target);
	return access(target, F_OK) == 0 && access(targetdep(target), F_OK) != 0;
}

static int
check_deps(char *target)
{
	char *depfile;
	FILE *f;
	int ok = 1;
	int fd;

	target = targetchdir(target);

	if (access(target, F_OK) != 0)
		return 0;

	depfile = targetdep(target);
	f = fopen(depfile, "r");
	if (!f)
		return 0;

	while (ok && !feof(f)) {
		char line[4096];
		char *hash = line + 1;
		char *timestamp = line + 1 + 64 + 1;
		char *filename = line + 1 + 64 + 1 + 16 + 1;

		if (fgets(line, sizeof line, f)) {
			line[strlen(line)-1] = 0; // strip \n
			switch (line[0]) {
			case '-':  // must not exist 
				if (access(line+1, F_OK) == 0)
					ok = 0;
				break;
			case '=':  // compare hash
				fd = open(filename, O_RDONLY);
				if (fd < 0) {
					ok = 0;
				} else {
					if (strncmp(timestamp, datefile(fd), 16) != 0 &&
					    strncmp(hash, hashfile(fd), 64) != 0)
						ok = 0;
					close(fd);
				}
				// hash is good, recurse into dependencies
				if (ok && strcmp(target, filename) != 0 &&
				    !sourcefile(filename))
					ok = check_deps(filename);
				break;
			case '!':  // always rebuild
			default:  // dep file broken, lets recreate it
				ok = 0;
			}
		} else {
			if (!feof(f)) {
				ok = 0;
				break;
			}
		}
	}

	fclose(f);

	return ok;
}

void
vacate(int implicit) {
	if (implicit)
		implicit_jobs++;
	else
		write(poolwr_fd, "\0", 1);
}

struct job {
	struct job *next;
	pid_t pid;
	char *target, *temp_depfile, *temp_target;
	int implicit;
};
struct job *jobhead;

static void
insert_job(struct job *job)
{
	job->next = jobhead;
	jobhead = job;
}

static void
remove_job(struct job *job)
{
	if (jobhead == job)
		jobhead = jobhead->next;
	else {
		struct job *j = jobhead;
		while (j->next != job)
			j = j->next;
		j->next = j->next->next;
	}
}

static struct job *
find_job(pid_t pid)
{
	struct job *j;

	for (j = jobhead; j; j = j->next) {
		if (j->pid == pid)
			return j;
	}

	return 0;
}

static int
write_dep(int dep_fd, char *file) {
	int fd = open(file, O_RDONLY);
	if (fd < 0)
		return 0;
	dprintf(dep_fd, "=%s %s %s\n", hashfile(fd), datefile(fd), file);
	close(fd);
	return 0;
}

int
new_waitjob(int fd, int implicit)
{
	pid_t pid;

	pid = fork();
	if (pid < 0) {
		perror("fork");
		vacate(implicit);
		exit(-1);
	} else if (pid == 0) { // child
		lockf(fd, F_LOCK, 0);
		close(fd);
		exit(0);
	} else {
		struct job *job = malloc (sizeof *job);
		if (!job)
			exit(-1);
		job->target = 0;
		job->pid = pid;
		job->implicit = implicit;

		insert_job(job);
	}

	return 0;
}

static void
run_script(char *target, int implicit)
{
	char temp_depfile[] = ".depend.XXXXXX";
	char temp_target_base[] = ".target.XXXXXX";
	char temp_target[PATH_MAX], rel_target[PATH_MAX], cwd[PATH_MAX];
	char *orig_target = target;
	int old_dep_fd = dep_fd;
	int target_fd;
	char *dofile, *dirprefix;
	pid_t pid;

	target = targetchdir(target);

	int fd = open(targetlock(target), O_WRONLY | O_TRUNC | O_CREAT, 0666);
	if (lockf(fd, F_TLOCK, 0) < 0) {
		if (errno == EAGAIN) {
			fprintf(stderr, "redo: %s already building, waiting.\n",
			    orig_target);
			new_waitjob(fd, implicit);
			return;
		} else {
			perror("lockf");
			exit(111);
		}
	}

	dep_fd = mkstemp(temp_depfile);

	target_fd = mkstemp(temp_target_base);

	dofile = find_dofile(target);
	if (!dofile) {
		fprintf(stderr, "no dofile for %s.\n", target);
		exit(1);
	}

	fprintf(stderr, "redo%*.*s %s # %s\n", level*2, level*2, " ", orig_target, dofile);
	write_dep(dep_fd, dofile);

	// .do files are called from the directory they reside in, we need to
	// prefix the arguments with the path from the dofile to the target
	getcwd(cwd, sizeof cwd);
	dirprefix = strchr(cwd, '\0');
	dofile += 2;  // find_dofile starts with ./ always
	while (strncmp(dofile, "../", 3) == 0) {
		chdir("..");
		dofile += 3;
		while (*--dirprefix != '/')
			;
	}
	if (*dirprefix)
		dirprefix++;

	snprintf(temp_target, sizeof temp_target,
	    "%s%s%s", dirprefix, "/"+(*dirprefix ? 0 : 1), temp_target_base);
	snprintf(rel_target, sizeof rel_target,
	    "%s%s%s", dirprefix, "/"+(*dirprefix ? 0 : 1), target);

	pid = fork();
	if (pid < 0) {
		perror("fork");
		vacate(implicit);
		exit(-1);
	} else if (pid == 0) { // child
/*
djb-style default.o.do:
   $1	   foo.o
   $2	   foo
   $3	   whatever.tmp

   $1	   all
   $2	   all (!!)
   $3	   whatever.tmp
*/
		int i;

		char *basename = strdup(rel_target);
		if (strchr(basename, '.')) {
			for (i = strlen(basename)-1; i && basename[i] != '.'; i--)
				basename[i] = 0;
			basename[i--] = 0;
		}

		if (old_dep_fd > 0)
			close(old_dep_fd);
		setenvfd("REDO_DEP_FD", dep_fd);
		setenvfd("REDO_LEVEL", level + 1);
		if (sflag > 0)
			dup2(target_fd, 1);
		else
			close(target_fd);

		if (access (dofile, X_OK) != 0)  // run -x files with /bin/sh
			execl("/bin/sh", "/bin/sh", xflag > 0 ? "-ex" : "-e",
			    dofile, rel_target, basename, temp_target, (char *) 0);
		else
			execl(dofile,
			    dofile, rel_target, basename, temp_target, (char *) 0);
		vacate(implicit);
		exit(-1);
	} else {
		struct job *job = malloc (sizeof *job);
		if (!job)
			exit(-1);

		close(target_fd);
		close(dep_fd);
		dep_fd = old_dep_fd;

		job->pid = pid;
		job->target = orig_target;
		job->temp_depfile = strdup(temp_depfile);
		job->temp_target = strdup(temp_target_base);
		job->implicit = implicit;

		insert_job(job);
	}
}

static int
try_procure()
{
	if (implicit_jobs > 0) {
		implicit_jobs--;
		return 1;
	} else {
		struct pollfd p;

		if (poolrd_fd < 0)
			return 0;

		p.fd = poolrd_fd;
		p.events = POLLIN;

		if (poll(&p, 1, 0) > 0 && p.revents & POLLIN) {
			char buf[1];
			return read(poolrd_fd, &buf, 1) > 0;
		}
		return 0;
	}
}

static int
procure()
{
	if (implicit_jobs > 0) {
		implicit_jobs--;
		return 1;
	} else {
		char buf[1];
		return read(poolrd_fd, &buf, 1) > 0;
	}
}

void
create_pool()
{
	poolrd_fd = envfd("REDO_RD_FD");
	poolwr_fd = envfd("REDO_WR_FD");
	if (poolrd_fd < 0 || poolwr_fd < 0) {
		int jobs = envfd("JOBS");
		if (jobs > 1) {
			int i, fds[2];
			pipe(fds);
			poolrd_fd = fds[0];
			poolwr_fd = fds[1];
			
			for (i = 0; i < jobs-1; i++)
				vacate(0);

			setenvfd("REDO_RD_FD", poolrd_fd);
			setenvfd("REDO_WR_FD", poolwr_fd);
		} else {
			poolrd_fd = -1;
			poolwr_fd = -1;
		}
	}
}

static void
redo_ifchange(int targetc, char *targetv[])
{
	pid_t pid;
	int status;
	struct job *job;

	int targeti = 0;

	// XXX
	char skip[targetc];

	create_pool();

	// check all targets whether needing rebuild
	for (targeti = 0; targeti < targetc; targeti++)
		skip[targeti] = fflag > 0 ? 0 : check_deps(targetv[targeti]);
	
	targeti = 0;
	while (1) {
		int procured = 0;
		if (targeti < targetc) {
			char *target = targetv[targeti];

			if (skip[targeti] || sourcefile(target)) {
				targeti++;
				continue;
			}

			if (try_procure()) {
				procured = 1;
				targeti++;
				run_script(target, implicit_jobs >= 0);
			}
		}

		pid = waitpid(-1, &status, procured ? WNOHANG : 0);

		if (pid == 0)
			continue;  // nohang

		if (pid < 0) {
			if (errno == ECHILD && targeti < targetc)
				continue;   // no child yet???
			else
				break;	 // no child left
		}

		if (WIFEXITED(status))
			status = WEXITSTATUS(status);

		job = find_job(pid);
		
		if (!job) {
			exit(-1);
		}
		remove_job(job);

		if (job->target) {
			if (status > 0) {
				remove(job->temp_depfile);
				remove(job->temp_target);
			} else {
				struct stat st;
				char *target = targetchdir(job->target);
				char *depfile = targetdep(target);

				if (stat(job->temp_target, &st) == 0 &&
				    st.st_size > 0) {
					int dfd;

					rename(job->temp_target, target);
					dfd = open(job->temp_depfile,
					    O_WRONLY | O_APPEND);
					write_dep(dfd, target);
					close(dfd);
				} else {
					remove(job->temp_target);
				}

				rename(job->temp_depfile, depfile);
				remove(targetlock(target));
			}
		}

		vacate(job->implicit);
		
		if (kflag < 0 && status > 0) {
			printf("failed with status %d\n", status);
			exit(status);
		}
	}
}

static void
record_deps(int targetc, char *targetv[])
{
	int targeti = 0;
	int fd;

	dep_fd = envfd("REDO_DEP_FD");
	if (dep_fd < 0)
		return;

	for (targeti = 0; targeti < targetc; targeti++) {
		fd = open(targetv[targeti], O_RDONLY);
		if (fd < 0)
			continue;
		// here, we write out the unmodified target name!
		write_dep(dep_fd, targetv[targeti]);
		close(fd);
	}
}

int
main(int argc, char *argv[])
{
	char *program;
	int opt, i;

	dep_fd = envfd("REDO_DEP_FD");

	level = envfd("REDO_LEVEL");
	if (level < 0)
		level = 0;

	fflag = envfd("REDO_FORCE");
	kflag = envfd("REDO_KEEP_GOING");
	xflag = envfd("REDO_TRACE");
	sflag = envfd("REDO_STDOUT");

	if ((program = strrchr(argv[0], '/')))
		program++;
	else
		program = argv[0];

	while ((opt = getopt(argc, argv, "+kxfsj:C:")) != -1) {
		switch (opt) {
		case 'k':
			kflag = 1;
			setenvfd("REDO_KEEP_GOING", 1);
			break;
		case 'x':
			xflag = 1;
			setenvfd("REDO_TRACE", 1);
			break;
		case 'f':
			fflag = 1;
			setenvfd("REDO_FORCE", 1);
			break;
		case 's':
			sflag = 1;
			setenvfd("REDO_STDOUT", 1);
			break;
		case 'j':
			setenv("JOBS", optarg, 1);
			break;
		case 'C':
			if (chdir(optarg) < 0) {
				perror("chdir");
				exit(-1);
			}
			break;
		default:
			fprintf(stderr, "usage: %s [-kfsx] [-jN] [-Cdir] [TARGETS...]\n", program);
			exit(1);
		}
	}
	argc -= optind;
	argv += optind;

	if (argc == 0) {
		argc = 1;
		argv[0] = (char *) "all";   // XXX safe?
	}

	dir_fd = open(".", O_RDONLY | O_DIRECTORY | O_CLOEXEC);
	if (dir_fd < 0) {
		perror("dir open");
		exit(-1);
	}

	if (strcmp(program, "redo") == 0) {
		fflag = 1;
		redo_ifchange(argc, argv);
		procure();
	} else if (strcmp(program, "redo-ifchange") == 0) {
		redo_ifchange(argc, argv);
		record_deps(argc, argv);
		procure();
	} else if (strcmp(program, "redo-ifcreate") == 0) {
		for (i = 0; i < argc; i++)
			redo_ifcreate(argv[i]);
	} else if (strcmp(program, "redo-always") == 0) {
		dprintf(dep_fd, "!\n");
	} else if (strcmp(program, "redo-hash") == 0) {
		for (i = 0; i < argc; i++)
			write_dep(1, argv[i]);
	} else {
		fprintf(stderr, "not implemented %s\n", program);
		exit(-1);
	}

	return 0;
}