t32vfs.c - plan9port - [fork] Plan 9 from user space
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t32vfs.c (3930B)
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1 /*
2 * Vax 32V Unix filesystem (same as pre-FFS Berkeley)
3 */
4 #include <u.h>
5 #include <libc.h>
6 #include <auth.h>
7 #include <fcall.h>
8 #include "tapefs.h"
9
10 /*
11 * v32 disk inode
12 */
13 #define VNADDR 13
14 #define VFMT 0160000
15 #define VIFREG 0100000
16 #define VIFDIR 0040000
17 #define VIFCHR 0120000
18 #define VIFBLK 0160000
19 #define VMODE 0777
20 #define VSUPERB 1
21 #define VROOT 2 /* root inode */
22 #define VNAMELEN 14
23 #define MAXBLSIZE 1024
24 int BLSIZE;
25 #define LINOPB (BLSIZE/sizeof(struct v32dinode))
26 #define LNINDIR (BLSIZE/4)
27 #define MAXLNINDIR (MAXBLSIZE/4)
28
29 struct v32dinode {
30 unsigned char flags[2];
31 unsigned char nlinks[2];
32 unsigned char uid[2];
33 unsigned char gid[2];
34 unsigned char size[4];
35 unsigned char addr[40];
36 unsigned char atime[4];
37 unsigned char mtime[4];
38 unsigned char ctime[4];
39 };
40
41 struct v32dir {
42 uchar ino[2];
43 char name[VNAMELEN];
44 };
45
46 int tapefile;
47 Fileinf iget(int ino);
48 long bmap(Ram *r, long bno);
49 void getblk(Ram *r, long bno, char *buf);
50
51 void
52 populate(char *name)
53 {
54 Fileinf f;
55
56 BLSIZE = 512; /* 32v */
57 if(blocksize){
58 /* 1024 for 4.1BSD */
59 if(blocksize != 512 && blocksize != 1024)
60 error("bad block size");
61 BLSIZE = blocksize;
62 }
63 replete = 0;
64 tapefile = open(name, OREAD);
65 if (tapefile<0)
66 error("Can't open argument file");
67 f = iget(VROOT);
68 ram->perm = f.mode;
69 ram->mtime = f.mdate;
70 ram->addr = f.addr;
71 ram->data = f.data;
72 ram->ndata = f.size;
73 }
74
75 void
76 popdir(Ram *r)
77 {
78 int i, ino;
79 char *cp;
80 struct v32dir *dp;
81 Fileinf f;
82 char name[VNAMELEN+1];
83
84 cp = 0;
85 for (i=0; i<r->ndata; i+=sizeof(struct v32dir)) {
86 if (i%BLSIZE==0)
87 cp = doread(r, i, BLSIZE);
88 dp = (struct v32dir *)(cp+i%BLSIZE);
89 ino = g2byte(dp->ino);
90 if (strcmp(dp->name, ".")==0 || strcmp(dp->name, "..")==0)
91 continue;
92 if (ino==0)
93 continue;
94 f = iget(ino);
95 strncpy(name, dp->name, VNAMELEN);
96 name[VNAMELEN] = '\0';
97 f.name = name;
98 popfile(r, f);
99 }
100 r->replete = 1;
101 }
102
103 void
104 dotrunc(Ram *r)
105 {
106 USED(r);
107 }
108
109 void
110 docreate(Ram *r)
111 {
112 USED(r);
113 }
114
115 char *
116 doread(Ram *r, vlong off, long cnt)
117 {
118 static char buf[Maxbuf+MAXBLSIZE];
119 int bno, i;
120
121 bno = off/BLSIZE;
122 off -= bno*BLSIZE;
123 if (cnt>Maxbuf)
124 error("count too large");
125 if (off)
126 cnt += off;
127 i = 0;
128 while (cnt>0) {
129 getblk(r, bno, &buf[i*BLSIZE]);
130 cnt -= BLSIZE;
131 bno++;
132 i++;
133 }
134 return buf;
135 }
136
137 void
138 dowrite(Ram *r, char *buf, long off, long cnt)
139 {
140 USED(r); USED(buf); USED(off); USED(cnt);
141 }
142
143 int
144 dopermw(Ram *r)
145 {
146 USED(r);
147 return 0;
148 }
149
150 /*
151 * fetch an i-node
152 * -- no sanity check for now
153 * -- magic inode-to-disk-block stuff here
154 */
155
156 Fileinf
157 iget(int ino)
158 {
159 char buf[MAXBLSIZE];
160 struct v32dinode *dp;
161 long flags, i;
162 Fileinf f;
163
164 memset(&f, 0, sizeof f);
165 seek(tapefile, BLSIZE*((ino-1)/LINOPB + VSUPERB + 1), 0);
166 if (read(tapefile, buf, BLSIZE) != BLSIZE)
167 error("Can't read inode");
168 dp = ((struct v32dinode *)buf) + ((ino-1)%LINOPB);
169 flags = g2byte(dp->flags);
170 f.size = g4byte(dp->size);
171 if ((flags&VFMT)==VIFCHR || (flags&VFMT)==VIFBLK)
172 f.size = 0;
173 f.data = emalloc(VNADDR*sizeof(long));
174 for (i = 0; i < VNADDR; i++)
175 ((long*)f.data)[i] = g3byte(dp->addr+3*i);
176 f.mode = flags & VMODE;
177 if ((flags&VFMT)==VIFDIR)
178 f.mode |= DMDIR;
179 f.uid = g2byte(dp->uid);
180 f.gid = g2byte(dp->gid);
181 f.mdate = g4byte(dp->mtime);
182 return f;
183 }
184
185 void
186 getblk(Ram *r, long bno, char *buf)
187 {
188 long dbno;
189
190 if ((dbno = bmap(r, bno)) == 0) {
191 memset(buf, 0, BLSIZE);
192 return;
193 }
194 seek(tapefile, dbno*BLSIZE, 0);
195 if (read(tapefile, buf, BLSIZE) != BLSIZE)
196 error("bad read");
197 }
198
199 /*
200 * logical to physical block
201 * only singly-indirect files for now
202 */
203
204 long
205 bmap(Ram *r, long bno)
206 {
207 unsigned char indbuf[LNINDIR][sizeof(long)];
208
209 if (bno < VNADDR-3)
210 return ((long*)r->data)[bno];
211 if (bno < VNADDR*LNINDIR) {
212 seek(tapefile, ((long *)r->data)[(bno-(VNADDR-3))/LNINDIR]*BLSIZE, 0);
213 if (read(tapefile, (char *)indbuf, BLSIZE) != BLSIZE)
214 return 0;
215 return ((indbuf[bno%LNINDIR][1]<<8) + indbuf[bno%LNINDIR][0]);
216 }
217 return 0;
218 }