1 /*
2  * old (V6 and before) PDP-11 Unix filesystem
3  */
4 #include <u.h>
5 #include <libc.h>
6 #include <auth.h>
7 #include <fcall.h>
8 #include "tapefs.h"
9 
10 /*
11  * v6 disk inode
12  */
13 #define	V6NADDR	8
14 #define	V6FMT	0160000
15 #define	V6IFREG	0100000
16 #define	V6IFDIR	0140000
17 #define	V6IFCHR	0120000
18 #define	V6IFBLK	0160000
19 #define	V6MODE	0777
20 #define	V6LARGE	010000
21 #define	V6SUPERB	1
22 #define	V6ROOT		1	/* root inode */
23 #define	V6NAMELEN	14
24 #define	BLSIZE	512
25 #define	LINOPB	(BLSIZE/sizeof(struct v6dinode))
26 #define	LNINDIR	(BLSIZE/sizeof(unsigned short))
27 
28 struct v6dinode {
29 	unsigned char flags[2];
30 	unsigned char nlinks;
31 	unsigned char uid;
32 	unsigned char gid;
33 	unsigned char hisize;
34 	unsigned char losize[2];
35 	unsigned char addr[V6NADDR][2];
36 	unsigned char atime[4];	/* pdp-11 order */
37 	unsigned char mtime[4];	/* pdp-11 order */
38 };
39 
40 struct	v6dir {
41 	uchar	ino[2];
42 	char	name[V6NAMELEN];
43 };
44 
45 int	tapefile;
46 Fileinf	iget(int ino);
47 long	bmap(Ram *r, long bno);
48 void	getblk(Ram *r, long bno, char *buf);
49 
50 void
51 populate(char *name)
52 {
53 	Fileinf f;
54 
55 	replete = 0;
56 	tapefile = open(name, OREAD);
57 	if (tapefile<0)
58 		error("Can't open argument file");
59 	f = iget(V6ROOT);
60 	ram->perm = f.mode;
61 	ram->mtime = f.mdate;
62 	ram->addr = f.addr;
63 	ram->data = f.data;
64 	ram->ndata = f.size;
65 }
66 
67 void
68 popdir(Ram *r)
69 {
70 	int i, ino;
71 	char *cp;
72 	struct v6dir *dp;
73 	Fileinf f;
74 	char name[V6NAMELEN+1];
75 
76 	cp = 0;
77 	for (i=0; i<r->ndata; i+=sizeof(struct v6dir)) {
78 		if (i%BLSIZE==0)
79 			cp = doread(r, i, BLSIZE);
80 		dp = (struct v6dir *)(cp+i%BLSIZE);
81 		ino = dp->ino[0] + (dp->ino[1]<<8);
82 		if (strcmp(dp->name, ".")==0 || strcmp(dp->name, "..")==0)
83 			continue;
84 		if (ino==0)
85 			continue;
86 		f = iget(ino);
87 		strncpy(name, dp->name, V6NAMELEN);
88 		name[V6NAMELEN] = '\0';
89 		f.name = name;
90 		popfile(r, f);
91 	}
92 	r->replete = 1;
93 }
94 
95 void
96 dotrunc(Ram *r)
97 {
98 	USED(r);
99 }
100 
101 void
102 docreate(Ram *r)
103 {
104 	USED(r);
105 }
106 
107 char *
108 doread(Ram *r, vlong off, long cnt)
109 {
110 	static char buf[Maxbuf+BLSIZE];
111 	int bno, i;
112 
113 	bno = off/BLSIZE;
114 	off -= bno*BLSIZE;
115 	if (cnt>Maxbuf)
116 		error("count too large");
117 	if (off)
118 		cnt += off;
119 	i = 0;
120 	while (cnt>0) {
121 		getblk(r, bno, &buf[i*BLSIZE]);
122 		cnt -= BLSIZE;
123 		bno++;
124 		i++;
125 	}
126 	return buf;
127 }
128 
129 void
130 dowrite(Ram *r, char *buf, long off, long cnt)
131 {
132 	USED(r); USED(buf); USED(off); USED(cnt);
133 }
134 
135 int
136 dopermw(Ram *r)
137 {
138 	USED(r);
139 	return 0;
140 }
141 
142 /*
143  * fetch an i-node
144  * -- no sanity check for now
145  * -- magic inode-to-disk-block stuff here
146  */
147 
148 Fileinf
149 iget(int ino)
150 {
151 	char buf[BLSIZE];
152 	struct v6dinode *dp;
153 	long flags, i;
154 	Fileinf f;
155 
156 	memset(&f, 0, sizeof f);
157 	seek(tapefile, BLSIZE*((ino-1)/LINOPB + V6SUPERB + 1), 0);
158 	if (read(tapefile, buf, BLSIZE) != BLSIZE)
159 		error("Can't read inode");
160 	dp = ((struct v6dinode *)buf) + ((ino-1)%LINOPB);
161 	flags = (dp->flags[1]<<8) + dp->flags[0];
162 	f.size = (dp->hisize << 16) + (dp->losize[1]<<8) + dp->losize[0];
163 	if ((flags&V6FMT)==V6IFCHR || (flags&V6FMT)==V6IFBLK)
164 		f.size = 0;
165 	f.data = emalloc(V6NADDR*sizeof(ushort));
166 	for (i = 0; i < V6NADDR; i++)
167 		((ushort*)f.data)[i] = (dp->addr[i][1]<<8) + dp->addr[i][0];
168 	f.mode = flags & V6MODE;
169 	if ((flags&V6FMT)==V6IFDIR)
170 		f.mode |= DMDIR;
171 	f.uid = dp->uid;
172 	f.gid = dp->gid;
173 	f.mdate = (dp->mtime[2]<<0) + (dp->mtime[3]<<8)
174 	     +(dp->mtime[0]<<16) + (dp->mtime[1]<<24);
175 	return f;
176 }
177 
178 void
179 getblk(Ram *r, long bno, char *buf)
180 {
181 	long dbno;
182 
183 	if ((dbno = bmap(r, bno)) == 0) {
184 		memset(buf, 0, BLSIZE);
185 		return;
186 	}
187 	seek(tapefile, dbno*BLSIZE, 0);
188 	if (read(tapefile, buf, BLSIZE) != BLSIZE)
189 		error("bad read");
190 }
191 
192 /*
193  * logical to physical block
194  * only singly-indirect files for now
195  */
196 
197 long
198 bmap(Ram *r, long bno)
199 {
200 	unsigned char indbuf[LNINDIR][2];
201 
202 	if (r->ndata <= V6NADDR*BLSIZE) {	/* assume size predicts largeness of file */
203 		if (bno < V6NADDR)
204 			return ((ushort*)r->data)[bno];
205 		return 0;
206 	}
207 	if (bno < V6NADDR*LNINDIR) {
208 		seek(tapefile, ((ushort *)r->data)[bno/LNINDIR]*BLSIZE, 0);
209 		if (read(tapefile, (char *)indbuf, BLSIZE) != BLSIZE)
210 			return 0;
211 		return ((indbuf[bno%LNINDIR][1]<<8) + indbuf[bno%LNINDIR][0]);
212 	}
213 	return 0;
214 }