summaryrefslogtreecommitdiff
path: root/bootstrap/bmake/arch.c
blob: c2f840b2bc1b178e861440fd7612b4db3a194736 (plain)
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
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
/*	$NetBSD: arch.c,v 1.1.1.1 2004/03/11 13:04:01 grant Exp $	*/

/*
 * Copyright (c) 1988, 1989, 1990, 1993
 *	The Regents of the University of California.  All rights reserved.
 * Copyright (c) 1989 by Berkeley Softworks
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Adam de Boor.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifdef MAKE_BOOTSTRAP
static char rcsid[] = "$NetBSD: arch.c,v 1.1.1.1 2004/03/11 13:04:01 grant Exp $";
#else
#include <sys/cdefs.h>
#ifndef lint
#if 0
static char sccsid[] = "@(#)arch.c	8.2 (Berkeley) 1/2/94";
#else
__RCSID("$NetBSD: arch.c,v 1.1.1.1 2004/03/11 13:04:01 grant Exp $");
#endif
#endif /* not lint */
#endif

#if !defined(MAKE_BOOTSTRAP) && !defined(lint)
__IDSTRING(rcs_id,"$Id: arch.c,v 1.1.1.1 2004/03/11 13:04:01 grant Exp $");
#endif

/*-
 * arch.c --
 *	Functions to manipulate libraries, archives and their members.
 *
 *	Once again, cacheing/hashing comes into play in the manipulation
 * of archives. The first time an archive is referenced, all of its members'
 * headers are read and hashed and the archive closed again. All hashed
 * archives are kept on a list which is searched each time an archive member
 * is referenced.
 *
 * The interface to this module is:
 *	Arch_ParseArchive   	Given an archive specification, return a list
 *	    	  	    	of GNode's, one for each member in the spec.
 *	    	  	    	FAILURE is returned if the specification is
 *	    	  	    	invalid for some reason.
 *
 *	Arch_Touch	    	Alter the modification time of the archive
 *	    	  	    	member described by the given node to be
 *	    	  	    	the current time.
 *
 *	Arch_TouchLib	    	Update the modification time of the library
 *	    	  	    	described by the given node. This is special
 *	    	  	    	because it also updates the modification time
 *	    	  	    	of the library's table of contents.
 *
 *	Arch_MTime	    	Find the modification time of a member of
 *	    	  	    	an archive *in the archive*. The time is also
 *	    	  	    	placed in the member's GNode. Returns the
 *	    	  	    	modification time.
 *
 *	Arch_MemTime	    	Find the modification time of a member of
 *	    	  	    	an archive. Called when the member doesn't
 *	    	  	    	already exist. Looks in the archive for the
 *	    	  	    	modification time. Returns the modification
 *	    	  	    	time.
 *
 *	Arch_FindLib	    	Search for a library along a path. The
 *	    	  	    	library name in the GNode should be in
 *	    	  	    	-l<name> format.
 *
 *	Arch_LibOODate	    	Special function to decide if a library node
 *	    	  	    	is out-of-date.
 *
 *	Arch_Init 	    	Initialize this module.
 *
 *	Arch_End 	    	Cleanup this module.
 */

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#include    <sys/types.h>
#include    <sys/stat.h>
#include    <sys/time.h>
#include    <sys/param.h>
#include    <ctype.h>
#ifdef HAVE_AR_H
#include    <ar.h>
#endif
#ifdef HAVE_RANLIB_H
#include    <ranlib.h>
#endif
#ifdef HAVE_UTIME_H
#include    <utime.h>
#endif
#include    <stdio.h>
#include    <stdlib.h>
#include    <fcntl.h>
#include    "make.h"
#include    "hash.h"
#include    "dir.h"

#ifdef TARGET_MACHINE
#undef MACHINE
#define MACHINE TARGET_MACHINE
#endif
#ifdef TARGET_MACHINE_ARCH
#undef MACHINE_ARCH
#define MACHINE_ARCH TARGET_MACHINE_ARCH
#endif

static Lst	  archives;   /* Lst of archives we've already examined */

typedef struct Arch {
    char	  *name;      /* Name of archive */
    Hash_Table	  members;    /* All the members of the archive described
			       * by <name, struct ar_hdr *> key/value pairs */
    char	  *fnametab;  /* Extended name table strings */
    size_t	  fnamesize;  /* Size of the string table */
} Arch;

static int ArchFindArchive __P((ClientData, ClientData));
#ifdef CLEANUP
static void ArchFree __P((ClientData));
#endif
static struct ar_hdr *ArchStatMember __P((char *, char *, Boolean));
static FILE *ArchFindMember __P((char *, char *, struct ar_hdr *, char *));
#if defined(__svr4__) || defined(__SVR4) || defined(__ELF__)
#define SVR4ARCHIVES
static int ArchSVR4Entry __P((Arch *, char *, size_t, FILE *));
#endif


#if defined(_AIX)
# define AR_NAME _ar_name.ar_name
# define AR_FMAG _ar_name.ar_fmag
# define SARMAG  SAIAMAG
# define ARMAG   AIAMAG
# define ARFMAG  AIAFMAG
#endif
#ifndef  AR_NAME
# define AR_NAME ar_name
#endif
#ifndef  AR_DATE
# define AR_DATE ar_date
#endif
#ifndef  AR_SIZE
# define AR_SIZE ar_size
#endif
#ifndef  AR_FMAG
# define AR_FMAG ar_fmag
#endif

#define AR_MAX_NAME_LEN	    (sizeof(arh.AR_NAME)-1)

#ifdef CLEANUP
/*-
 *-----------------------------------------------------------------------
 * ArchFree --
 *	Free memory used by an archive
 *
 * Results:
 *	None.
 *
 * Side Effects:
 *	None.
 *
 *-----------------------------------------------------------------------
 */
static void
ArchFree(ap)
    ClientData ap;
{
    Arch *a = (Arch *) ap;
    Hash_Search	  search;
    Hash_Entry	  *entry;

    /* Free memory from hash entries */
    for (entry = Hash_EnumFirst(&a->members, &search);
	 entry != (Hash_Entry *)NULL;
	 entry = Hash_EnumNext(&search))
	free((Address) Hash_GetValue (entry));

    free(a->name);
    if (a->fnametab)
	free(a->fnametab);
    Hash_DeleteTable(&a->members);
    free((Address) a);
}
#endif


/*-
 *-----------------------------------------------------------------------
 * Arch_ParseArchive --
 *	Parse the archive specification in the given line and find/create
 *	the nodes for the specified archive members, placing their nodes
 *	on the given list.
 *
 * Results:
 *	SUCCESS if it was a valid specification. The linePtr is updated
 *	to point to the first non-space after the archive spec. The
 *	nodes for the members are placed on the given list.
 *
 * Side Effects:
 *	Some nodes may be created. The given list is extended.
 *
 *-----------------------------------------------------------------------
 */
ReturnStatus
Arch_ParseArchive (linePtr, nodeLst, ctxt)
    char	    **linePtr;      /* Pointer to start of specification */
    Lst	    	    nodeLst;   	    /* Lst on which to place the nodes */
    GNode   	    *ctxt;  	    /* Context in which to expand variables */
{
    register char   *cp;	    /* Pointer into line */
    GNode	    *gn;     	    /* New node */
    char	    *libName;  	    /* Library-part of specification */
    char	    *memName;  	    /* Member-part of specification */
    char	    *nameBuf;	    /* temporary place for node name */
    char	    saveChar;  	    /* Ending delimiter of member-name */
    Boolean 	    subLibName;	    /* TRUE if libName should have/had
				     * variable substitution performed on it */

    libName = *linePtr;

    subLibName = FALSE;

    for (cp = libName; *cp != '(' && *cp != '\0'; cp++) {
	if (*cp == '$') {
	    /*
	     * Variable spec, so call the Var module to parse the puppy
	     * so we can safely advance beyond it...
	     */
	    int 	length;
	    Boolean	freeIt;
	    char	*result;

	    result=Var_Parse(cp, ctxt, TRUE, &length, &freeIt);
	    if (result == var_Error) {
		return(FAILURE);
	    } else {
		subLibName = TRUE;
	    }

	    if (freeIt) {
		free(result);
	    }
	    cp += length-1;
	}
    }

    *cp++ = '\0';
    if (subLibName) {
	libName = Var_Subst(NULL, libName, ctxt, TRUE);
    }


    for (;;) {
	/*
	 * First skip to the start of the member's name, mark that
	 * place and skip to the end of it (either white-space or
	 * a close paren).
	 */
	Boolean	doSubst = FALSE; /* TRUE if need to substitute in memName */

	while (*cp != '\0' && *cp != ')' && isspace ((unsigned char)*cp)) {
	    cp++;
	}
	memName = cp;
	while (*cp != '\0' && *cp != ')' && !isspace ((unsigned char)*cp)) {
	    if (*cp == '$') {
		/*
		 * Variable spec, so call the Var module to parse the puppy
		 * so we can safely advance beyond it...
		 */
		int 	length;
		Boolean	freeIt;
		char	*result;

		result=Var_Parse(cp, ctxt, TRUE, &length, &freeIt);
		if (result == var_Error) {
		    return(FAILURE);
		} else {
		    doSubst = TRUE;
		}

		if (freeIt) {
		    free(result);
		}
		cp += length;
	    } else {
		cp++;
	    }
	}

	/*
	 * If the specification ends without a closing parenthesis,
	 * chances are there's something wrong (like a missing backslash),
	 * so it's better to return failure than allow such things to happen
	 */
	if (*cp == '\0') {
	    printf("No closing parenthesis in archive specification\n");
	    return (FAILURE);
	}

	/*
	 * If we didn't move anywhere, we must be done
	 */
	if (cp == memName) {
	    break;
	}

	saveChar = *cp;
	*cp = '\0';

	/*
	 * XXX: This should be taken care of intelligently by
	 * SuffExpandChildren, both for the archive and the member portions.
	 */
	/*
	 * If member contains variables, try and substitute for them.
	 * This will slow down archive specs with dynamic sources, of course,
	 * since we'll be (non-)substituting them three times, but them's
	 * the breaks -- we need to do this since SuffExpandChildren calls
	 * us, otherwise we could assume the thing would be taken care of
	 * later.
	 */
	if (doSubst) {
	    char    *buf;
	    char    *sacrifice;
	    char    *oldMemName = memName;
	    size_t   sz;

	    memName = Var_Subst(NULL, memName, ctxt, TRUE);

	    /*
	     * Now form an archive spec and recurse to deal with nested
	     * variables and multi-word variable values.... The results
	     * are just placed at the end of the nodeLst we're returning.
	     */
	    sz = strlen(memName)+strlen(libName)+3;
	    buf = sacrifice = emalloc(sz);

	    snprintf(buf, sz, "%s(%s)", libName, memName);

	    if (strchr(memName, '$') && strcmp(memName, oldMemName) == 0) {
		/*
		 * Must contain dynamic sources, so we can't deal with it now.
		 * Just create an ARCHV node for the thing and let
		 * SuffExpandChildren handle it...
		 */
		gn = Targ_FindNode(buf, TARG_CREATE);

		if (gn == NILGNODE) {
		    free(buf);
		    return(FAILURE);
		} else {
		    gn->type |= OP_ARCHV;
		    (void)Lst_AtEnd(nodeLst, (ClientData)gn);
		}
	    } else if (Arch_ParseArchive(&sacrifice, nodeLst, ctxt)!=SUCCESS) {
		/*
		 * Error in nested call -- free buffer and return FAILURE
		 * ourselves.
		 */
		free(buf);
		return(FAILURE);
	    }
	    /*
	     * Free buffer and continue with our work.
	     */
	    free(buf);
	} else if (Dir_HasWildcards(memName)) {
	    Lst	  members = Lst_Init(FALSE);
	    char  *member;
	    size_t sz = MAXPATHLEN, nsz;
	    nameBuf = emalloc(sz);

	    Dir_Expand(memName, dirSearchPath, members);
	    while (!Lst_IsEmpty(members)) {
		member = (char *)Lst_DeQueue(members);
		nsz = strlen(libName) + strlen(member) + 3;
		if (sz > nsz)
		    nameBuf = erealloc(nameBuf, sz = nsz * 2);

		snprintf(nameBuf, sz, "%s(%s)", libName, member);
		free(member);
		gn = Targ_FindNode (nameBuf, TARG_CREATE);
		if (gn == NILGNODE) {
		    free(nameBuf);
		    return (FAILURE);
		} else {
		    /*
		     * We've found the node, but have to make sure the rest of
		     * the world knows it's an archive member, without having
		     * to constantly check for parentheses, so we type the
		     * thing with the OP_ARCHV bit before we place it on the
		     * end of the provided list.
		     */
		    gn->type |= OP_ARCHV;
		    (void) Lst_AtEnd (nodeLst, (ClientData)gn);
		}
	    }
	    Lst_Destroy(members, NOFREE);
	    free(nameBuf);
	} else {
	    size_t	sz = strlen(libName) + strlen(memName) + 3;
	    nameBuf = emalloc(sz);
	    snprintf(nameBuf, sz, "%s(%s)", libName, memName);
	    gn = Targ_FindNode (nameBuf, TARG_CREATE);
	    free(nameBuf);
	    if (gn == NILGNODE) {
		return (FAILURE);
	    } else {
		/*
		 * We've found the node, but have to make sure the rest of the
		 * world knows it's an archive member, without having to
		 * constantly check for parentheses, so we type the thing with
		 * the OP_ARCHV bit before we place it on the end of the
		 * provided list.
		 */
		gn->type |= OP_ARCHV;
		(void) Lst_AtEnd (nodeLst, (ClientData)gn);
	    }
	}
	if (doSubst) {
	    free(memName);
	}

	*cp = saveChar;
    }

    /*
     * If substituted libName, free it now, since we need it no longer.
     */
    if (subLibName) {
	free(libName);
    }

    /*
     * We promised the pointer would be set up at the next non-space, so
     * we must advance cp there before setting *linePtr... (note that on
     * entrance to the loop, cp is guaranteed to point at a ')')
     */
    do {
	cp++;
    } while (*cp != '\0' && isspace ((unsigned char)*cp));

    *linePtr = cp;
    return (SUCCESS);
}

/*-
 *-----------------------------------------------------------------------
 * ArchFindArchive --
 *	See if the given archive is the one we are looking for. Called
 *	From ArchStatMember and ArchFindMember via Lst_Find.
 *
 * Results:
 *	0 if it is, non-zero if it isn't.
 *
 * Side Effects:
 *	None.
 *
 *-----------------------------------------------------------------------
 */
static int
ArchFindArchive (ar, archName)
    ClientData	  ar;	      	  /* Current list element */
    ClientData	  archName;  	  /* Name we want */
{
    return (strcmp ((char *) archName, ((Arch *) ar)->name));
}

/*-
 *-----------------------------------------------------------------------
 * ArchStatMember --
 *	Locate a member of an archive, given the path of the archive and
 *	the path of the desired member.
 *
 * Results:
 *	A pointer to the current struct ar_hdr structure for the member. Note
 *	That no position is returned, so this is not useful for touching
 *	archive members. This is mostly because we have no assurances that
 *	The archive will remain constant after we read all the headers, so
 *	there's not much point in remembering the position...
 *
 * Side Effects:
 *
 *-----------------------------------------------------------------------
 */
static struct ar_hdr *
ArchStatMember (archive, member, hash)
    char	  *archive;   /* Path to the archive */
    char	  *member;    /* Name of member. If it is a path, only the
			       * last component is used. */
    Boolean	  hash;	      /* TRUE if archive should be hashed if not
    			       * already so. */
{
    FILE *	  arch;	      /* Stream to archive */
    int		  size;       /* Size of archive member */
    char	  *cp;	      /* Useful character pointer */
    char	  magic[SARMAG];
    LstNode	  ln;	      /* Lst member containing archive descriptor */
    Arch	  *ar;	      /* Archive descriptor */
    Hash_Entry	  *he;	      /* Entry containing member's description */
    struct ar_hdr arh;        /* archive-member header for reading archive */
    char	  memName[MAXPATHLEN+1];
    	    	    	    /* Current member name while hashing. */

    /*
     * Because of space constraints and similar things, files are archived
     * using their final path components, not the entire thing, so we need
     * to point 'member' to the final component, if there is one, to make
     * the comparisons easier...
     */
    cp = strrchr (member, '/');
    if (cp != (char *) NULL) {
	member = cp + 1;
    }

    ln = Lst_Find (archives, (ClientData) archive, ArchFindArchive);
    if (ln != NILLNODE) {
	ar = (Arch *) Lst_Datum (ln);

	he = Hash_FindEntry (&ar->members, member);

	if (he != (Hash_Entry *) NULL) {
	    return ((struct ar_hdr *) Hash_GetValue (he));
	} else {
	    /* Try truncated name */
	    char copy[AR_MAX_NAME_LEN+1];
	    int len = strlen (member);

	    if (len > AR_MAX_NAME_LEN) {
		len = AR_MAX_NAME_LEN;
		strncpy(copy, member, AR_MAX_NAME_LEN);
		copy[AR_MAX_NAME_LEN] = '\0';
	    }
	    if ((he = Hash_FindEntry (&ar->members, copy)) != NULL)
		return ((struct ar_hdr *) Hash_GetValue (he));
	    return ((struct ar_hdr *) NULL);
	}
    }

    if (!hash) {
	/*
	 * Caller doesn't want the thing hashed, just use ArchFindMember
	 * to read the header for the member out and close down the stream
	 * again. Since the archive is not to be hashed, we assume there's
	 * no need to allocate extra room for the header we're returning,
	 * so just declare it static.
	 */
	 static struct ar_hdr	sarh;

	 arch = ArchFindMember(archive, member, &sarh, "r");

	 if (arch == (FILE *)NULL) {
	    return ((struct ar_hdr *)NULL);
	} else {
	    fclose(arch);
	    return (&sarh);
	}
    }

    /*
     * We don't have this archive on the list yet, so we want to find out
     * everything that's in it and cache it so we can get at it quickly.
     */
    arch = fopen (archive, "r");
    if (arch == (FILE *) NULL) {
	return ((struct ar_hdr *) NULL);
    }

    /*
     * We use the ARMAG string to make sure this is an archive we
     * can handle...
     */
    if ((fread (magic, SARMAG, 1, arch) != 1) ||
    	(strncmp (magic, ARMAG, SARMAG) != 0)) {
	    fclose (arch);
	    return ((struct ar_hdr *) NULL);
    }

    ar = (Arch *)emalloc (sizeof (Arch));
    ar->name = estrdup (archive);
    ar->fnametab = NULL;
    ar->fnamesize = 0;
    Hash_InitTable (&ar->members, -1);
    memName[AR_MAX_NAME_LEN] = '\0';

    while (fread ((char *)&arh, sizeof (struct ar_hdr), 1, arch) == 1) {
	if (strncmp ( arh.AR_FMAG, ARFMAG, sizeof (arh.AR_FMAG)) != 0) {
	    /*
	     * The header is bogus, so the archive is bad
	     * and there's no way we can recover...
	     */
	    goto badarch;
	} else {
	    /*
	     * We need to advance the stream's pointer to the start of the
	     * next header. Files are padded with newlines to an even-byte
	     * boundary, so we need to extract the size of the file from the
	     * 'size' field of the header and round it up during the seek.
	     */
	    arh.AR_SIZE[sizeof(arh.AR_SIZE)-1] = '\0';
	    size = (int) strtol(arh.AR_SIZE, NULL, 10);

	    (void) strncpy (memName, arh.AR_NAME, sizeof(arh.AR_NAME));
	    for (cp = &memName[AR_MAX_NAME_LEN]; *cp == ' '; cp--) {
		continue;
	    }
	    cp[1] = '\0';

#ifdef SVR4ARCHIVES
	    /*
	     * svr4 names are slash terminated. Also svr4 extended AR format.
	     */
	    if (memName[0] == '/') {
		/*
		 * svr4 magic mode; handle it
		 */
		switch (ArchSVR4Entry(ar, memName, size, arch)) {
		case -1:  /* Invalid data */
		    goto badarch;
		case 0:	  /* List of files entry */
		    continue;
		default:  /* Got the entry */
		    break;
		}
	    }
	    else {
		if (cp[0] == '/')
		    cp[0] = '\0';
	    }
#endif

#ifdef AR_EFMT1
	    /*
	     * BSD 4.4 extended AR format: #1/<namelen>, with name as the
	     * first <namelen> bytes of the file
	     */
	    if (strncmp(memName, AR_EFMT1, sizeof(AR_EFMT1) - 1) == 0 &&
		isdigit(memName[sizeof(AR_EFMT1) - 1])) {

		unsigned int elen = atoi(&memName[sizeof(AR_EFMT1)-1]);

		if (elen > MAXPATHLEN)
			goto badarch;
		if (fread (memName, elen, 1, arch) != 1)
			goto badarch;
		memName[elen] = '\0';
		fseek (arch, -elen, SEEK_CUR);
		if (DEBUG(ARCH) || DEBUG(MAKE)) {
		    printf("ArchStat: Extended format entry for %s\n", memName);
		}
	    }
#endif

	    he = Hash_CreateEntry (&ar->members, memName, (Boolean *)NULL);
	    Hash_SetValue (he, (ClientData)emalloc (sizeof (struct ar_hdr)));
	    memcpy ((Address)Hash_GetValue (he), (Address)&arh,
		sizeof (struct ar_hdr));
	}
	fseek (arch, (size + 1) & ~1, SEEK_CUR);
    }

    fclose (arch);

    (void) Lst_AtEnd (archives, (ClientData) ar);

    /*
     * Now that the archive has been read and cached, we can look into
     * the hash table to find the desired member's header.
     */
    he = Hash_FindEntry (&ar->members, member);

    if (he != (Hash_Entry *) NULL) {
	return ((struct ar_hdr *) Hash_GetValue (he));
    } else {
	return ((struct ar_hdr *) NULL);
    }

badarch:
    fclose (arch);
    Hash_DeleteTable (&ar->members);
    if (ar->fnametab)
	free(ar->fnametab);
    free ((Address)ar);
    return ((struct ar_hdr *) NULL);
}

#ifdef SVR4ARCHIVES
/*-
 *-----------------------------------------------------------------------
 * ArchSVR4Entry --
 *	Parse an SVR4 style entry that begins with a slash.
 *	If it is "//", then load the table of filenames
 *	If it is "/<offset>", then try to substitute the long file name
 *	from offset of a table previously read.
 *
 * Results:
 *	-1: Bad data in archive
 *	 0: A table was loaded from the file
 *	 1: Name was successfully substituted from table
 *	 2: Name was not successfully substituted from table
 *
 * Side Effects:
 *	If a table is read, the file pointer is moved to the next archive
 *	member
 *
 *-----------------------------------------------------------------------
 */
static int
ArchSVR4Entry(ar, name, size, arch)
	Arch *ar;
	char *name;
	size_t size;
	FILE *arch;
{
#define ARLONGNAMES1 "//"
#define ARLONGNAMES2 "/ARFILENAMES"
    size_t entry;
    char *ptr, *eptr;

    if (strncmp(name, ARLONGNAMES1, sizeof(ARLONGNAMES1) - 1) == 0 ||
	strncmp(name, ARLONGNAMES2, sizeof(ARLONGNAMES2) - 1) == 0) {

	if (ar->fnametab != NULL) {
	    if (DEBUG(ARCH)) {
		printf("Attempted to redefine an SVR4 name table\n");
	    }
	    return -1;
	}

	/*
	 * This is a table of archive names, so we build one for
	 * ourselves
	 */
	ar->fnametab = emalloc(size);
	ar->fnamesize = size;

	if (fread(ar->fnametab, size, 1, arch) != 1) {
	    if (DEBUG(ARCH)) {
		printf("Reading an SVR4 name table failed\n");
	    }
	    return -1;
	}
	eptr = ar->fnametab + size;
	for (entry = 0, ptr = ar->fnametab; ptr < eptr; ptr++)
	    switch (*ptr) {
	    case '/':
		entry++;
		*ptr = '\0';
		break;

	    case '\n':
		break;

	    default:
		break;
	    }
	if (DEBUG(ARCH)) {
	    printf("Found svr4 archive name table with %lu entries\n",
	            (u_long)entry);
	}
	return 0;
    }

    if (name[1] == ' ' || name[1] == '\0')
	return 2;

    entry = (size_t) strtol(&name[1], &eptr, 0);
    if ((*eptr != ' ' && *eptr != '\0') || eptr == &name[1]) {
	if (DEBUG(ARCH)) {
	    printf("Could not parse SVR4 name %s\n", name);
	}
	return 2;
    }
    if (entry >= ar->fnamesize) {
	if (DEBUG(ARCH)) {
	    printf("SVR4 entry offset %s is greater than %lu\n",
		   name, (u_long)ar->fnamesize);
	}
	return 2;
    }

    if (DEBUG(ARCH)) {
	printf("Replaced %s with %s\n", name, &ar->fnametab[entry]);
    }

    (void) strncpy(name, &ar->fnametab[entry], MAXPATHLEN);
    name[MAXPATHLEN] = '\0';
    return 1;
}
#endif


/*-
 *-----------------------------------------------------------------------
 * ArchFindMember --
 *	Locate a member of an archive, given the path of the archive and
 *	the path of the desired member. If the archive is to be modified,
 *	the mode should be "r+", if not, it should be "r".
 *
 * Results:
 *	An FILE *, opened for reading and writing, positioned at the
 *	start of the member's struct ar_hdr, or NULL if the member was
 *	nonexistent. The current struct ar_hdr for member.
 *
 * Side Effects:
 *	The passed struct ar_hdr structure is filled in.
 *
 *-----------------------------------------------------------------------
 */
static FILE *
ArchFindMember (archive, member, arhPtr, mode)
    char	  *archive;   /* Path to the archive */
    char	  *member;    /* Name of member. If it is a path, only the
			       * last component is used. */
    struct ar_hdr *arhPtr;    /* Pointer to header structure to be filled in */
    char	  *mode;      /* The mode for opening the stream */
{
    FILE *	  arch;	      /* Stream to archive */
    int		  size;       /* Size of archive member */
    char	  *cp;	      /* Useful character pointer */
    char	  magic[SARMAG];
    int		  len, tlen;

    arch = fopen (archive, mode);
    if (arch == (FILE *) NULL) {
	return ((FILE *) NULL);
    }

    /*
     * We use the ARMAG string to make sure this is an archive we
     * can handle...
     */
    if ((fread (magic, SARMAG, 1, arch) != 1) ||
    	(strncmp (magic, ARMAG, SARMAG) != 0)) {
	    fclose (arch);
	    return ((FILE *) NULL);
    }

    /*
     * Because of space constraints and similar things, files are archived
     * using their final path components, not the entire thing, so we need
     * to point 'member' to the final component, if there is one, to make
     * the comparisons easier...
     */
    cp = strrchr (member, '/');
    if (cp != (char *) NULL) {
	member = cp + 1;
    }
    len = tlen = strlen (member);
    if (len > sizeof (arhPtr->AR_NAME)) {
	tlen = sizeof (arhPtr->AR_NAME);
    }

    while (fread ((char *)arhPtr, sizeof (struct ar_hdr), 1, arch) == 1) {
	if (strncmp(arhPtr->AR_FMAG, ARFMAG, sizeof (arhPtr->AR_FMAG) ) != 0) {
	     /*
	      * The header is bogus, so the archive is bad
	      * and there's no way we can recover...
	      */
	     fclose (arch);
	     return ((FILE *) NULL);
	} else if (strncmp (member, arhPtr->AR_NAME, tlen) == 0) {
	    /*
	     * If the member's name doesn't take up the entire 'name' field,
	     * we have to be careful of matching prefixes. Names are space-
	     * padded to the right, so if the character in 'name' at the end
	     * of the matched string is anything but a space, this isn't the
	     * member we sought.
	     */
	    if (tlen != sizeof(arhPtr->AR_NAME) && arhPtr->AR_NAME[tlen] != ' '){
		goto skip;
	    } else {
		/*
		 * To make life easier, we reposition the file at the start
		 * of the header we just read before we return the stream.
		 * In a more general situation, it might be better to leave
		 * the file at the actual member, rather than its header, but
		 * not here...
		 */
		fseek (arch, -sizeof(struct ar_hdr), SEEK_CUR);
		return (arch);
	    }
	} else
#ifdef AR_EFMT1
		/*
		 * BSD 4.4 extended AR format: #1/<namelen>, with name as the
		 * first <namelen> bytes of the file
		 */
	    if (strncmp(arhPtr->AR_NAME, AR_EFMT1,
					sizeof(AR_EFMT1) - 1) == 0 &&
		isdigit(arhPtr->AR_NAME[sizeof(AR_EFMT1) - 1])) {

		unsigned int elen = atoi(&arhPtr->AR_NAME[sizeof(AR_EFMT1)-1]);
		char ename[MAXPATHLEN];

		if (elen > MAXPATHLEN) {
			fclose (arch);
			return NULL;
		}
		if (fread (ename, elen, 1, arch) != 1) {
			fclose (arch);
			return NULL;
		}
		ename[elen] = '\0';
		if (DEBUG(ARCH) || DEBUG(MAKE)) {
		    printf("ArchFind: Extended format entry for %s\n", ename);
		}
		if (strncmp(ename, member, len) == 0) {
			/* Found as extended name */
			fseek (arch, -sizeof(struct ar_hdr) - elen, SEEK_CUR);
			return (arch);
		}
		fseek (arch, -elen, SEEK_CUR);
		goto skip;
	} else
#endif
	{
skip:
	    /*
	     * This isn't the member we're after, so we need to advance the
	     * stream's pointer to the start of the next header. Files are
	     * padded with newlines to an even-byte boundary, so we need to
	     * extract the size of the file from the 'size' field of the
	     * header and round it up during the seek.
	     */
	    arhPtr->AR_SIZE[sizeof(arhPtr->AR_SIZE)-1] = '\0';
	    size = (int) strtol(arhPtr->AR_SIZE, NULL, 10);
	    fseek (arch, (size + 1) & ~1, SEEK_CUR);
	}
    }

    /*
     * We've looked everywhere, but the member is not to be found. Close the
     * archive and return NULL -- an error.
     */
    fclose (arch);
    return ((FILE *) NULL);
}

/*-
 *-----------------------------------------------------------------------
 * Arch_Touch --
 *	Touch a member of an archive.
 *
 * Results:
 *	The 'time' field of the member's header is updated.
 *
 * Side Effects:
 *	The modification time of the entire archive is also changed.
 *	For a library, this could necessitate the re-ranlib'ing of the
 *	whole thing.
 *
 *-----------------------------------------------------------------------
 */
void
Arch_Touch (gn)
    GNode	  *gn;	  /* Node of member to touch */
{
    FILE *	  arch;	  /* Stream open to archive, positioned properly */
    struct ar_hdr arh;	  /* Current header describing member */
    char *p1, *p2;

    arch = ArchFindMember(Var_Value (ARCHIVE, gn, &p1),
			  Var_Value (MEMBER, gn, &p2),
			  &arh, "r+");
    if (p1)
	free(p1);
    if (p2)
	free(p2);
    snprintf(arh.AR_DATE, sizeof(arh.AR_DATE), "%-12ld", (long) now);

    if (arch != (FILE *) NULL) {
	(void)fwrite ((char *)&arh, sizeof (struct ar_hdr), 1, arch);
	fclose (arch);
    }
}

/*-
 *-----------------------------------------------------------------------
 * Arch_TouchLib --
 *	Given a node which represents a library, touch the thing, making
 *	sure that the table of contents also is touched.
 *
 * Results:
 *	None.
 *
 * Side Effects:
 *	Both the modification time of the library and of the RANLIBMAG
 *	member are set to 'now'.
 *
 *-----------------------------------------------------------------------
 */
void
Arch_TouchLib (gn)
    GNode	    *gn;      	/* The node of the library to touch */
{
#ifdef RANLIBMAG
    FILE *	    arch;	/* Stream open to archive */
    struct ar_hdr   arh;      	/* Header describing table of contents */
    struct utimbuf  times;	/* Times for utime() call */

    arch = ArchFindMember (gn->path, RANLIBMAG, &arh, "r+");
    snprintf(arh.AR_DATE, sizeof(arh.AR_DATE), "%-12ld", (long) now);

    if (arch != (FILE *) NULL) {
	(void)fwrite ((char *)&arh, sizeof (struct ar_hdr), 1, arch);
	fclose (arch);

	times.actime = times.modtime = now;
	utime(gn->path, &times);
    }
#endif
}

/*-
 *-----------------------------------------------------------------------
 * Arch_MTime --
 *	Return the modification time of a member of an archive.
 *
 * Results:
 *	The modification time (seconds).
 *
 * Side Effects:
 *	The mtime field of the given node is filled in with the value
 *	returned by the function.
 *
 *-----------------------------------------------------------------------
 */
time_t
Arch_MTime (gn)
    GNode	  *gn;	      /* Node describing archive member */
{
    struct ar_hdr *arhPtr;    /* Header of desired member */
    time_t	  modTime;    /* Modification time as an integer */
    char *p1, *p2;

    arhPtr = ArchStatMember (Var_Value (ARCHIVE, gn, &p1),
			     Var_Value (MEMBER, gn, &p2),
			     TRUE);
    if (p1)
	free(p1);
    if (p2)
	free(p2);

    if (arhPtr != (struct ar_hdr *) NULL) {
	modTime = (time_t) strtol(arhPtr->AR_DATE, NULL, 10);
    } else {
	modTime = 0;
    }

    gn->mtime = modTime;
    return (modTime);
}

/*-
 *-----------------------------------------------------------------------
 * Arch_MemMTime --
 *	Given a non-existent archive member's node, get its modification
 *	time from its archived form, if it exists.
 *
 * Results:
 *	The modification time.
 *
 * Side Effects:
 *	The mtime field is filled in.
 *
 *-----------------------------------------------------------------------
 */
time_t
Arch_MemMTime (gn)
    GNode   	  *gn;
{
    LstNode 	  ln;
    GNode   	  *pgn;
    char    	  *nameStart,
		  *nameEnd;

    if (Lst_Open (gn->parents) != SUCCESS) {
	gn->mtime = 0;
	return (0);
    }
    while ((ln = Lst_Next (gn->parents)) != NILLNODE) {
	pgn = (GNode *) Lst_Datum (ln);

	if (pgn->type & OP_ARCHV) {
	    /*
	     * If the parent is an archive specification and is being made
	     * and its member's name matches the name of the node we were
	     * given, record the modification time of the parent in the
	     * child. We keep searching its parents in case some other
	     * parent requires this child to exist...
	     */
	    nameStart = strchr (pgn->name, '(') + 1;
	    nameEnd = strchr (nameStart, ')');

	    if ((pgn->flags & REMAKE) &&
		strncmp(nameStart, gn->name, nameEnd - nameStart) == 0) {
				     gn->mtime = Arch_MTime(pgn);
	    }
	} else if (pgn->flags & REMAKE) {
	    /*
	     * Something which isn't a library depends on the existence of
	     * this target, so it needs to exist.
	     */
	    gn->mtime = 0;
	    break;
	}
    }

    Lst_Close (gn->parents);

    return (gn->mtime);
}

/*-
 *-----------------------------------------------------------------------
 * Arch_FindLib --
 *	Search for a library along the given search path.
 *
 * Results:
 *	None.
 *
 * Side Effects:
 *	The node's 'path' field is set to the found path (including the
 *	actual file name, not -l...). If the system can handle the -L
 *	flag when linking (or we cannot find the library), we assume that
 *	the user has placed the .LIBRARIES variable in the final linking
 *	command (or the linker will know where to find it) and set the
 *	TARGET variable for this node to be the node's name. Otherwise,
 *	we set the TARGET variable to be the full path of the library,
 *	as returned by Dir_FindFile.
 *
 *-----------------------------------------------------------------------
 */
void
Arch_FindLib (gn, path)
    GNode	    *gn;	      /* Node of library to find */
    Lst	    	    path;	      /* Search path */
{
    char	    *libName;   /* file name for archive */
    size_t	     sz = strlen(gn->name) + 6 - 2;

    libName = (char *)emalloc(sz);
    snprintf(libName, sz, "lib%s.a", &gn->name[2]);

    gn->path = Dir_FindFile (libName, path);

    free (libName);

#ifdef LIBRARIES
    Var_Set (TARGET, gn->name, gn, 0);
#else
    Var_Set (TARGET, gn->path == (char *) NULL ? gn->name : gn->path, gn, 0);
#endif /* LIBRARIES */
}

/*-
 *-----------------------------------------------------------------------
 * Arch_LibOODate --
 *	Decide if a node with the OP_LIB attribute is out-of-date. Called
 *	from Make_OODate to make its life easier.
 *
 *	There are several ways for a library to be out-of-date that are
 *	not available to ordinary files. In addition, there are ways
 *	that are open to regular files that are not available to
 *	libraries. A library that is only used as a source is never
 *	considered out-of-date by itself. This does not preclude the
 *	library's modification time from making its parent be out-of-date.
 *	A library will be considered out-of-date for any of these reasons,
 *	given that it is a target on a dependency line somewhere:
 *	    Its modification time is less than that of one of its
 *	    	  sources (gn->mtime < gn->cmtime).
 *	    Its modification time is greater than the time at which the
 *	    	  make began (i.e. it's been modified in the course
 *	    	  of the make, probably by archiving).
 *	    The modification time of one of its sources is greater than
 *		  the one of its RANLIBMAG member (i.e. its table of contents
 *	    	  is out-of-date). We don't compare of the archive time
 *		  vs. TOC time because they can be too close. In my
 *		  opinion we should not bother with the TOC at all since
 *		  this is used by 'ar' rules that affect the data contents
 *		  of the archive, not by ranlib rules, which affect the
 *		  TOC.
 *
 * Results:
 *	TRUE if the library is out-of-date. FALSE otherwise.
 *
 * Side Effects:
 *	The library will be hashed if it hasn't been already.
 *
 *-----------------------------------------------------------------------
 */
Boolean
Arch_LibOODate (gn)
    GNode   	  *gn;  	/* The library's graph node */
{
    Boolean 	  oodate;

    if (gn->type & OP_PHONY) {
	oodate = TRUE;
    } else if (OP_NOP(gn->type) && Lst_IsEmpty(gn->children)) {
	oodate = FALSE;
    } else if ((gn->cmtime == 0) || (gn->mtime > now) ||
	       (gn->mtime < gn->cmtime)) {
	oodate = TRUE;
    } else {
#ifdef RANLIBMAG
	struct ar_hdr  	*arhPtr;    /* Header for __.SYMDEF */
	int 	  	modTimeTOC; /* The table-of-contents's mod time */

	arhPtr = ArchStatMember (gn->path, RANLIBMAG, FALSE);

	if (arhPtr != (struct ar_hdr *)NULL) {
	    modTimeTOC = (int) strtol(arhPtr->AR_DATE, NULL, 10);

	    if (DEBUG(ARCH) || DEBUG(MAKE)) {
		printf("%s modified %s...", RANLIBMAG, Targ_FmtTime(modTimeTOC));
	    }
	    oodate = (gn->cmtime > modTimeTOC);
	} else {
	    /*
	     * A library w/o a table of contents is out-of-date
	     */
	    if (DEBUG(ARCH) || DEBUG(MAKE)) {
		printf("No t.o.c....");
	    }
	    oodate = TRUE;
	}
#else
	oodate = FALSE;
#endif
    }
    return (oodate);
}

/*-
 *-----------------------------------------------------------------------
 * Arch_Init --
 *	Initialize things for this module.
 *
 * Results:
 *	None.
 *
 * Side Effects:
 *	The 'archives' list is initialized.
 *
 *-----------------------------------------------------------------------
 */
void
Arch_Init ()
{
    archives = Lst_Init (FALSE);
}



/*-
 *-----------------------------------------------------------------------
 * Arch_End --
 *	Cleanup things for this module.
 *
 * Results:
 *	None.
 *
 * Side Effects:
 *	The 'archives' list is freed
 *
 *-----------------------------------------------------------------------
 */
void
Arch_End ()
{
#ifdef CLEANUP
    Lst_Destroy(archives, ArchFree);
#endif
}

/*-
 *-----------------------------------------------------------------------
 * Arch_IsLib --
 *	Check if the node is a library
 *
 * Results:
 *	True or False.
 *
 * Side Effects:
 *	None.
 *
 *-----------------------------------------------------------------------
 */
int
Arch_IsLib(gn)
    GNode *gn;
{
    static const char armag[] = "!<arch>\n";
    char buf[sizeof(armag)-1];
    int fd;

    if ((fd = open(gn->path, O_RDONLY)) == -1)
	return FALSE;

    if (read(fd, buf, sizeof(buf)) != sizeof(buf)) {
	(void) close(fd);
	return FALSE;
    }

    (void) close(fd);

    return memcmp(buf, armag, sizeof(buf)) == 0;
}