tv6fs.c - plan9port - [fork] Plan 9 from user space
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tv6fs.c (4016B)
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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 }