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6459ebe0 KM |
1 | /* subr_xxx.c 4.10 82/04/19 */ |
2 | ||
3 | /* merged into kernel: @(#)subr.c 2.2 4/8/82 */ | |
ae9e2121 BJ |
4 | |
5 | #include "../h/param.h" | |
6 | #include "../h/systm.h" | |
7 | #include "../h/conf.h" | |
8 | #include "../h/inode.h" | |
9 | #include "../h/dir.h" | |
10 | #include "../h/user.h" | |
11 | #include "../h/buf.h" | |
12 | #include "../h/proc.h" | |
6459ebe0 | 13 | #include "../h/fs.h" |
ae9e2121 BJ |
14 | |
15 | /* | |
16 | * Bmap defines the structure of file system storage | |
17 | * by returning the physical block number on a device given the | |
18 | * inode and the logical block number in a file. | |
19 | * When convenient, it also leaves the physical | |
20 | * block number of the next block of the file in rablock | |
21 | * for use in read-ahead. | |
22 | */ | |
6459ebe0 | 23 | /*VARARGS3*/ |
ae9e2121 | 24 | daddr_t |
6459ebe0 KM |
25 | bmap(ip, bn, rwflg, size) |
26 | register struct inode *ip; | |
27 | daddr_t bn; | |
28 | int rwflg; | |
29 | int size; /* supplied only when rwflg == B_WRITE */ | |
ae9e2121 | 30 | { |
6459ebe0 KM |
31 | register int i; |
32 | int osize, nsize; | |
ae9e2121 | 33 | struct buf *bp, *nbp; |
6459ebe0 | 34 | struct fs *fs; |
ae9e2121 | 35 | int j, sh; |
6459ebe0 | 36 | daddr_t nb, *bap, pref, blkpref(); |
ae9e2121 | 37 | |
6459ebe0 | 38 | if (bn < 0) { |
ae9e2121 | 39 | u.u_error = EFBIG; |
6459ebe0 | 40 | return ((daddr_t)0); |
ae9e2121 | 41 | } |
6459ebe0 | 42 | fs = ip->i_fs; |
ae9e2121 BJ |
43 | rablock = 0; |
44 | ||
45 | /* | |
6459ebe0 KM |
46 | * If the next write will extend the file into a new block, |
47 | * and the file is currently composed of a fragment | |
48 | * this fragment has to be extended to be a full block. | |
ae9e2121 | 49 | */ |
6459ebe0 KM |
50 | nb = lblkno(fs, ip->i_size); |
51 | if (rwflg == B_WRITE && nb < NDADDR && nb < bn) { | |
52 | osize = blksize(fs, ip, nb); | |
53 | if (osize < fs->fs_bsize && osize > 0) { | |
54 | bp = realloccg(ip, ip->i_db[nb], | |
55 | nb == 0 ? 0 : ip->i_db[nb - 1] + fs->fs_frag, | |
56 | osize, fs->fs_bsize); | |
57 | ip->i_size = (nb + 1) * fs->fs_bsize; | |
58 | ip->i_db[nb] = dbtofsb(fs, bp->b_blkno); | |
59 | ip->i_flag |= IUPD|ICHG; | |
60 | bdwrite(bp); | |
61 | } | |
62 | } | |
63 | /* | |
64 | * The first NDADDR blocks are direct blocks | |
65 | */ | |
66 | if (bn < NDADDR) { | |
ae9e2121 | 67 | i = bn; |
6459ebe0 KM |
68 | nb = ip->i_db[i]; |
69 | if (rwflg == B_READ) { | |
70 | if (nb == 0) | |
71 | return ((daddr_t)-1); | |
72 | goto gotit; | |
73 | } | |
74 | if (nb == 0 || ip->i_size < (i + 1) * fs->fs_bsize) { | |
75 | if (nb != 0) { | |
76 | /* consider need to reallocate a frag */ | |
77 | osize = fragroundup(fs, blkoff(fs, ip->i_size)); | |
78 | nsize = fragroundup(fs, size); | |
79 | if (nsize <= osize) | |
80 | goto gotit; | |
81 | bp = realloccg(ip, nb, i == 0 ? | |
82 | 0 : ip->i_db[i - 1] + fs->fs_frag, | |
83 | osize, nsize); | |
84 | } else { | |
85 | if (ip->i_size < (i + 1) * fs->fs_bsize) | |
86 | nsize = fragroundup(fs, size); | |
87 | else | |
88 | nsize = fs->fs_bsize; | |
89 | bp = alloc(ip, i > 0 ? | |
90 | ip->i_db[i - 1] + fs->fs_frag : 0, | |
91 | nsize); | |
92 | } | |
93 | if (bp == NULL) | |
94 | return ((daddr_t)-1); | |
95 | nb = dbtofsb(fs, bp->b_blkno); | |
c0bb1685 BJ |
96 | if ((ip->i_mode&IFMT) == IFDIR) |
97 | /* | |
98 | * Write directory blocks synchronously | |
99 | * so they never appear with garbage in | |
100 | * them on the disk. | |
101 | */ | |
102 | bwrite(bp); | |
103 | else | |
104 | bdwrite(bp); | |
6459ebe0 | 105 | ip->i_db[i] = nb; |
ae9e2121 BJ |
106 | ip->i_flag |= IUPD|ICHG; |
107 | } | |
6459ebe0 KM |
108 | gotit: |
109 | if (i < NDADDR - 1) | |
110 | rablock = ip->i_db[i+1]; | |
111 | return (nb); | |
ae9e2121 BJ |
112 | } |
113 | ||
114 | /* | |
6459ebe0 | 115 | * Determine how many levels of indirection. |
ae9e2121 | 116 | */ |
6459ebe0 KM |
117 | sh = 1; |
118 | bn -= NDADDR; | |
119 | for (j = NIADDR; j>0; j--) { | |
120 | sh *= NINDIR(fs); | |
121 | if (bn < sh) | |
ae9e2121 | 122 | break; |
6459ebe0 | 123 | bn -= sh; |
ae9e2121 | 124 | } |
6459ebe0 | 125 | if (j == 0) { |
ae9e2121 | 126 | u.u_error = EFBIG; |
6459ebe0 | 127 | return ((daddr_t)0); |
ae9e2121 BJ |
128 | } |
129 | ||
130 | /* | |
c0bb1685 | 131 | * fetch the first indirect block |
ae9e2121 | 132 | */ |
6459ebe0 KM |
133 | nb = ip->i_ib[NIADDR - j]; |
134 | if (nb == 0) { | |
135 | if (rwflg==B_READ || | |
136 | (bp = alloc(ip, (daddr_t)0, fs->fs_bsize)) == NULL) | |
137 | return ((daddr_t)-1); | |
138 | nb = dbtofsb(fs, bp->b_blkno); | |
c0bb1685 BJ |
139 | /* |
140 | * Write synchronously so that indirect blocks | |
141 | * never point at garbage. | |
142 | */ | |
143 | bwrite(bp); | |
6459ebe0 | 144 | ip->i_ib[NIADDR - j] = nb; |
ae9e2121 BJ |
145 | ip->i_flag |= IUPD|ICHG; |
146 | } | |
147 | ||
148 | /* | |
149 | * fetch through the indirect blocks | |
150 | */ | |
6459ebe0 KM |
151 | for (; j <= NIADDR; j++) { |
152 | bp = bread(ip->i_dev, fsbtodb(fs, nb), fs->fs_bsize); | |
153 | if (bp->b_flags & B_ERROR) { | |
ae9e2121 | 154 | brelse(bp); |
6459ebe0 | 155 | return ((daddr_t)0); |
ae9e2121 BJ |
156 | } |
157 | bap = bp->b_un.b_daddr; | |
6459ebe0 KM |
158 | sh /= NINDIR(fs); |
159 | i = (bn / sh) % NINDIR(fs); | |
ae9e2121 | 160 | nb = bap[i]; |
6459ebe0 KM |
161 | if (nb == 0) { |
162 | if (rwflg==B_READ) { | |
163 | brelse(bp); | |
164 | return ((daddr_t)-1); | |
165 | } | |
166 | if (i % (fs->fs_fsize / sizeof(daddr_t)) == 0 || | |
167 | bap[i - 1] == 0) | |
168 | pref = blkpref(ip->i_fs); | |
169 | else | |
170 | pref = bap[i - 1] + fs->fs_frag; | |
171 | nbp = alloc(ip, pref, fs->fs_bsize); | |
172 | if (nbp == NULL) { | |
ae9e2121 | 173 | brelse(bp); |
6459ebe0 | 174 | return ((daddr_t)-1); |
ae9e2121 | 175 | } |
6459ebe0 KM |
176 | nb = dbtofsb(fs, nbp->b_blkno); |
177 | if (j < NIADDR || (ip->i_mode&IFMT) == IFDIR) | |
c0bb1685 BJ |
178 | /* |
179 | * Write synchronously so indirect blocks | |
180 | * never point at garbage and blocks | |
181 | * in directories never contain garbage. | |
182 | */ | |
183 | bwrite(nbp); | |
184 | else | |
185 | bdwrite(nbp); | |
ae9e2121 BJ |
186 | bap[i] = nb; |
187 | bdwrite(bp); | |
188 | } else | |
189 | brelse(bp); | |
190 | } | |
191 | ||
192 | /* | |
193 | * calculate read-ahead. | |
194 | */ | |
6459ebe0 | 195 | if (i < NINDIR(fs) - 1) |
ae9e2121 | 196 | rablock = bap[i+1]; |
6459ebe0 | 197 | return (nb); |
ae9e2121 BJ |
198 | } |
199 | ||
200 | /* | |
201 | * Pass back c to the user at his location u_base; | |
202 | * update u_base, u_count, and u_offset. Return -1 | |
203 | * on the last character of the user's read. | |
204 | * u_base is in the user address space unless u_segflg is set. | |
205 | */ | |
206 | passc(c) | |
207 | register c; | |
208 | { | |
209 | register id; | |
210 | ||
6459ebe0 | 211 | if ((id = u.u_segflg) == 1) |
ae9e2121 BJ |
212 | *u.u_base = c; |
213 | else | |
6459ebe0 | 214 | if (id?suibyte(u.u_base, c):subyte(u.u_base, c) < 0) { |
ae9e2121 | 215 | u.u_error = EFAULT; |
6459ebe0 | 216 | return (-1); |
ae9e2121 BJ |
217 | } |
218 | u.u_count--; | |
219 | u.u_offset++; | |
220 | u.u_base++; | |
6459ebe0 | 221 | return (u.u_count == 0? -1: 0); |
ae9e2121 BJ |
222 | } |
223 | ||
3d14758e | 224 | #include "ct.h" |
2752c877 | 225 | #if NCT > 0 |
ae9e2121 BJ |
226 | /* |
227 | * Pick up and return the next character from the user's | |
228 | * write call at location u_base; | |
229 | * update u_base, u_count, and u_offset. Return -1 | |
230 | * when u_count is exhausted. u_base is in the user's | |
231 | * address space unless u_segflg is set. | |
232 | */ | |
ae9e2121 BJ |
233 | cpass() |
234 | { | |
235 | register c, id; | |
236 | ||
6459ebe0 KM |
237 | if (u.u_count == 0) |
238 | return (-1); | |
239 | if ((id = u.u_segflg) == 1) | |
ae9e2121 BJ |
240 | c = *u.u_base; |
241 | else | |
6459ebe0 | 242 | if ((c = id==0?fubyte(u.u_base):fuibyte(u.u_base)) < 0) { |
ae9e2121 | 243 | u.u_error = EFAULT; |
6459ebe0 | 244 | return (-1); |
ae9e2121 BJ |
245 | } |
246 | u.u_count--; | |
247 | u.u_offset++; | |
248 | u.u_base++; | |
6459ebe0 | 249 | return (c&0377); |
ae9e2121 | 250 | } |
2752c877 | 251 | #endif |
ae9e2121 BJ |
252 | |
253 | /* | |
254 | * Routine which sets a user error; placed in | |
255 | * illegal entries in the bdevsw and cdevsw tables. | |
256 | */ | |
257 | nodev() | |
258 | { | |
259 | ||
260 | u.u_error = ENODEV; | |
261 | } | |
262 | ||
263 | /* | |
264 | * Null routine; placed in insignificant entries | |
265 | * in the bdevsw and cdevsw tables. | |
266 | */ | |
267 | nulldev() | |
268 | { | |
269 | ||
270 | } | |
271 | ||
272 | imin(a, b) | |
273 | { | |
274 | ||
275 | return (a < b ? a : b); | |
276 | } | |
277 | ||
278 | imax(a, b) | |
279 | { | |
280 | ||
281 | return (a > b ? a : b); | |
282 | } | |
283 | ||
6459ebe0 KM |
284 | unsigned |
285 | min(a, b) | |
286 | unsigned int a, b; | |
287 | { | |
288 | ||
289 | return (a < b ? a : b); | |
290 | } | |
291 | ||
292 | unsigned | |
293 | max(a, b) | |
294 | unsigned int a, b; | |
295 | { | |
296 | ||
297 | return (a > b ? a : b); | |
298 | } | |
299 | ||
ae9e2121 BJ |
300 | struct proc * |
301 | pfind(pid) | |
302 | int pid; | |
303 | { | |
304 | register struct proc *p; | |
305 | ||
306 | for (p = &proc[pidhash[PIDHASH(pid)]]; p != &proc[0]; p = &proc[p->p_idhash]) | |
307 | if (p->p_pid == pid) | |
308 | return (p); | |
309 | return ((struct proc *)0); | |
310 | } |