1 #include <u.h>
2 #include <libc.h>
3 #include <bio.h>
4 #include <libsec.h>
5 
6 #include "iso9660.h"
7 
8 /*
9  * Add the requisite path tables to the CD image.
10  * They get put on the end once everything else is done.
11  * We use the path table itself as a queue in the breadth-first
12  * traversal of the tree.
13  *
14  * The only problem with this is that the path table does not
15  * store the lengths of the directories.  So we keep an explicit
16  * map in an array in memory.
17  */
18 
19 enum {
20 	Big,
21 	Little
22 };
23 
24 static void
25 Crdpath(Cdimg *cd, Cpath *p)
26 {
27 	p->namelen = Cgetc(cd);
28 	if(p->namelen == 0) {
29 		Crseek(cd, (Croffset(cd)+Blocksize-1)/Blocksize * Blocksize);
30 		p->namelen = Cgetc(cd);
31 		assert(p->namelen != 0);
32 	}
33 
34 	p->xlen = Cgetc(cd);
35 	assert(p->xlen == 0);	/* sanity, might not be true if we start using the extended fields */
36 
37 	Cread(cd, p->dloc, 4);
38 	Cread(cd, p->parent, 2);
39 	p->name[0] = '\0';
40 	Crseek(cd, Croffset(cd)+p->namelen+p->xlen+(p->namelen&1));	/* skip name, ext data */
41 }
42 
43 static void
44 writepath(Cdimg *cd, Cdir *c, int parent, int size)
45 {
46 /*
47 	DO NOT UNCOMMENT THIS CODE.
48 	This commented-out code is here only so that no one comes
49 	along and adds it later.
50 
51 	The ISO 9660 spec is silent about whether path table entries
52 	need to be padded so that they never cross block boundaries.
53 	It would be reasonable to assume that they are like every other
54 	data structure in the bloody spec; this code pads them out.
55 
56 	Empirically, though, they're NOT padded.  Windows NT and
57 	derivatives are the only known current operating systems
58 	that actually read these things.
59 
60 	int l;
61 
62 	l = 1+1+4+2+c->namelen;
63 	if(Cwoffset(cd)/Blocksize != (Cwoffset(cd)+l)/Blocksize)
64 		Cpadblock(cd);
65 */
66 	Cputc(cd, c->namelen);
67 	Cputc(cd, 0);
68 	Cwrite(cd, c->dloc + (size==Little ? 0 : 4), 4);
69 	(size==Little ? Cputnl : Cputnm)(cd, parent, 2);
70 	Cwrite(cd, c->name, c->namelen);
71 	if(c->namelen & 1)
72 		Cputc(cd, 0);
73 }
74 
75 static ulong*
76 addlength(ulong *a, ulong x, int n)
77 {
78 	if(n%128==0)
79 		a = erealloc(a, (n+128)*sizeof a[0]);
80 	a[n] = x;
81 	return a;
82 }
83 
84 static ulong
85 writepathtable(Cdimg *cd, ulong vdblock, int size)
86 {
87 	int rp, wp;
88 	uchar buf[Blocksize];
89 	ulong bk, end, i, *len, n, rdoff, start;
90 	Cdir *c;
91 	Cpath p;
92 
93 	Creadblock(cd, buf, vdblock, Blocksize);
94 	c = (Cdir*)(buf+offsetof(Cvoldesc, rootdir[0]));
95 
96 	rp = 0;
97 	wp = 0;
98 	len = nil;
99 	start = cd->nextblock*Blocksize;
100 	Cwseek(cd, start);
101 	Crseek(cd, start);
102 	writepath(cd, c, 1, size);
103 	len = addlength(len, little(c->dlen, 4), wp);
104 	wp++;
105 
106 	while(rp < wp) {
107 		Crdpath(cd, &p);
108 		n = (len[rp]+Blocksize-1)/Blocksize;
109 		rp++;
110 		bk = (size==Big ? big : little)(p.dloc, 4);
111 		rdoff = Croffset(cd);
112 		for(i=0; i<n; i++) {
113 			Creadblock(cd, buf, bk+i, Blocksize);
114 			c = (Cdir*)buf;
115 			if(i != 0 && c->namelen == 1 && c->name[0] == '\0')	/* hit another directory; stop */
116 				break;
117 			while(c->len && c->namelen && (uchar*)c+c->len < buf+Blocksize) {
118 				if((c->flags & 0x02) && (c->namelen > 1 || c->name[0] > '\001')) {	/* directory */
119 					writepath(cd, c, rp, size);
120 					len = addlength(len, little(c->dlen, 4), wp);
121 					wp++;
122 				}
123 				c = (Cdir*)((uchar*)c+c->len);
124 			}
125 		}
126 		Crseek(cd, rdoff);
127 	}
128 	end = Cwoffset(cd);
129 	Cpadblock(cd);
130 	return end-start;
131 }
132 
133 
134 static void
135 writepathtablepair(Cdimg *cd, ulong vdblock)
136 {
137 	ulong bloc, lloc, sz, sz2;
138 
139 	lloc = cd->nextblock;
140 	sz = writepathtable(cd, vdblock, Little);
141 	bloc = cd->nextblock;
142 	sz2 = writepathtable(cd, vdblock, Big);
143 	assert(sz == sz2);
144 	setpathtable(cd, vdblock, sz, lloc, bloc);
145 }
146 
147 void
148 writepathtables(Cdimg *cd)
149 {
150 	cd->pathblock = cd->nextblock;
151 
152 	writepathtablepair(cd, cd->iso9660pvd);
153 	if(cd->flags & CDjoliet)
154 		writepathtablepair(cd, cd->jolietsvd);
155 }