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comparison src/sysfile.cbc @ 52:214d21c891c7

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rename to cbc __ncode is not handled as interfaces
author kono
date Mon, 03 Jun 2019 18:12:44 +0900
parents src/sysfile.c@36bd61f5c847
children f38d8d39d617
comparison
equal deleted inserted replaced
51:fadfd62d6b14 52:214d21c891c7
1 //
2 // File-system system calls.
3 // Mostly argument checking, since we don't trust
4 // user code, and calls into file.c and fs.c.
5 //
6
7 #include "types.h"
8 #include "defs.h"
9 #include "param.h"
10 #include "stat.h"
11 #include "mmu.h"
12 #include "proc.h"
13 #include "fs.h"
14 #include "file.h"
15 #include "fcntl.h"
16
17 #define __ncode __code
18
19 // Fetch the nth word-sized system call argument as a file descriptor
20 // and return both the descriptor and the corresponding struct file.
21 static int argfd(int n, int *pfd, struct file **pf)
22 {
23 int fd;
24 struct file *f;
25
26 if(argint(n, &fd) < 0) {
27 return -1;
28 }
29
30 if(fd < 0 || fd >= NOFILE || (f=proc->ofile[fd]) == 0) {
31 return -1;
32 }
33
34 if(pfd) {
35 *pfd = fd;
36 }
37
38 if(pf) {
39 *pf = f;
40 }
41
42 return 0;
43 }
44
45 // Allocate a file descriptor for the given file.
46 // Takes over file reference from caller on success.
47 static int fdalloc(struct file *f)
48 {
49 int fd;
50
51 for(fd = 0; fd < NOFILE; fd++){
52 if(proc->ofile[fd] == 0){
53 proc->ofile[fd] = f;
54 return fd;
55 }
56 }
57
58 return -1;
59 }
60
61 int sys_dup(void)
62 {
63 struct file *f;
64 int fd;
65
66 if(argfd(0, 0, &f) < 0) {
67 return -1;
68 }
69
70 if((fd=fdalloc(f)) < 0) {
71 return -1;
72 }
73
74 filedup(f);
75
76 return fd;
77 }
78
79 __ncode cbc_read(__code (*next)(int ret)){
80 struct file *f;
81 int n;
82 char *p;
83
84 if(argfd(0, 0, &f) < 0 || argint(2, &n) < 0 || argptr(1, &p, n) < 0) {
85 goto next(-1);
86 }
87 goto cbc_fileread(f, p, n, next);
88 }
89
90 int sys_read(void)
91 {
92 struct file *f;
93 int n;
94 char *p;
95
96 if(argfd(0, 0, &f) < 0 || argint(2, &n) < 0 || argptr(1, &p, n) < 0) {
97 return -1;
98 }
99
100 return fileread(f, p, n);
101 }
102
103 int sys_write(void)
104 {
105 struct file *f;
106 int n;
107 char *p;
108
109 if(argfd(0, 0, &f) < 0 || argint(2, &n) < 0 || argptr(1, &p, n) < 0) {
110 return -1;
111 }
112
113 return filewrite(f, p, n);
114 }
115
116 int sys_close(void)
117 {
118 int fd;
119 struct file *f;
120
121 if(argfd(0, &fd, &f) < 0) {
122 return -1;
123 }
124
125 proc->ofile[fd] = 0;
126 fileclose(f);
127
128 return 0;
129 }
130
131 int sys_fstat(void)
132 {
133 struct file *f;
134 struct stat *st;
135
136 if(argfd(0, 0, &f) < 0 || argptr(1, (void*)&st, sizeof(*st)) < 0) {
137 return -1;
138 }
139
140 return filestat(f, st);
141 }
142
143 // Create the path new as a link to the same inode as old.
144 int sys_link(void)
145 {
146 char name[DIRSIZ], *new, *old;
147 struct inode *dp, *ip;
148
149 if(argstr(0, &old) < 0 || argstr(1, &new) < 0) {
150 return -1;
151 }
152
153 if((ip = namei(old)) == 0) {
154 return -1;
155 }
156
157 begin_trans();
158
159 ilock(ip);
160
161 if(ip->type == T_DIR){
162 iunlockput(ip);
163 commit_trans();
164 return -1;
165 }
166
167 ip->nlink++;
168 iupdate(ip);
169 iunlock(ip);
170
171 if((dp = nameiparent(new, name)) == 0) {
172 goto bad;
173 }
174
175 ilock(dp);
176
177 if(dp->dev != ip->dev || dirlink(dp, name, ip->inum) < 0){
178 iunlockput(dp);
179 goto bad;
180 }
181
182 iunlockput(dp);
183 iput(ip);
184
185 commit_trans();
186
187 return 0;
188
189 bad:
190 ilock(ip);
191 ip->nlink--;
192 iupdate(ip);
193 iunlockput(ip);
194 commit_trans();
195 return -1;
196 }
197
198 // Is the directory dp empty except for "." and ".." ?
199 static int isdirempty(struct inode *dp)
200 {
201 int off;
202 struct dirent de;
203
204 for(off=2*sizeof(de); off<dp->size; off+=sizeof(de)){
205 if(readi(dp, (char*)&de, off, sizeof(de)) != sizeof(de)) {
206 panic("isdirempty: readi");
207 }
208
209 if(de.inum != 0) {
210 return 0;
211 }
212 }
213 return 1;
214 }
215
216 //PAGEBREAK!
217 int sys_unlink(void)
218 {
219 struct inode *ip, *dp;
220 struct dirent de;
221 char name[DIRSIZ], *path;
222 uint off;
223
224 if(argstr(0, &path) < 0) {
225 return -1;
226 }
227
228 if((dp = nameiparent(path, name)) == 0) {
229 return -1;
230 }
231
232 begin_trans();
233
234 ilock(dp);
235
236 // Cannot unlink "." or "..".
237 if(namecmp(name, ".") == 0 || namecmp(name, "..") == 0) {
238 goto bad;
239 }
240
241 if((ip = dirlookup(dp, name, &off)) == 0) {
242 goto bad;
243 }
244
245 ilock(ip);
246
247 if(ip->nlink < 1) {
248 panic("unlink: nlink < 1");
249 }
250
251 if(ip->type == T_DIR && !isdirempty(ip)){
252 iunlockput(ip);
253 goto bad;
254 }
255
256 memset(&de, 0, sizeof(de));
257
258 if(writei(dp, (char*)&de, off, sizeof(de)) != sizeof(de)) {
259 panic("unlink: writei");
260 }
261
262 if(ip->type == T_DIR){
263 dp->nlink--;
264 iupdate(dp);
265 }
266
267 iunlockput(dp);
268
269 ip->nlink--;
270 iupdate(ip);
271 iunlockput(ip);
272
273 commit_trans();
274
275 return 0;
276
277 bad:
278 iunlockput(dp);
279 commit_trans();
280 return -1;
281 }
282
283 static struct inode* create(char *path, short type, short major, short minor)
284 {
285 uint off;
286 struct inode *ip, *dp;
287 char name[DIRSIZ];
288
289 if((dp = nameiparent(path, name)) == 0) {
290 return 0;
291 }
292
293 ilock(dp);
294
295 if((ip = dirlookup(dp, name, &off)) != 0){
296 iunlockput(dp);
297 ilock(ip);
298
299 if(type == T_FILE && ip->type == T_FILE) {
300 return ip;
301 }
302
303 iunlockput(ip);
304
305 return 0;
306 }
307
308 if((ip = ialloc(dp->dev, type)) == 0) {
309 panic("create: ialloc");
310 }
311
312 ilock(ip);
313 ip->major = major;
314 ip->minor = minor;
315 ip->nlink = 1;
316 iupdate(ip);
317
318 if(type == T_DIR){ // Create . and .. entries.
319 dp->nlink++; // for ".."
320 iupdate(dp);
321
322 // No ip->nlink++ for ".": avoid cyclic ref count.
323 if(dirlink(ip, ".", ip->inum) < 0 || dirlink(ip, "..", dp->inum) < 0) {
324 panic("create dots");
325 }
326 }
327
328 if(dirlink(dp, name, ip->inum) < 0) {
329 panic("create: dirlink");
330 }
331
332 iunlockput(dp);
333
334 return ip;
335 }
336
337 int sys_open(void)
338 {
339 char *path;
340 int fd, omode;
341 struct file *f;
342 struct inode *ip;
343
344 if(argstr(0, &path) < 0 || argint(1, &omode) < 0) {
345 return -1;
346 }
347
348 if(omode & O_CREATE){
349 begin_trans();
350 ip = create(path, T_FILE, 0, 0);
351 commit_trans();
352
353 if(ip == 0) {
354 return -1;
355 }
356
357 } else {
358 if((ip = namei(path)) == 0) {
359 return -1;
360 }
361
362 ilock(ip);
363
364 if(ip->type == T_DIR && omode != O_RDONLY){
365 iunlockput(ip);
366 return -1;
367 }
368 }
369
370 if((f = filealloc()) == 0 || (fd = fdalloc(f)) < 0){
371 if(f) {
372 fileclose(f);
373 }
374
375 iunlockput(ip);
376 return -1;
377 }
378
379 iunlock(ip);
380
381 f->type = FD_INODE;
382 f->ip = ip;
383 f->off = 0;
384 f->readable = !(omode & O_WRONLY);
385 f->writable = (omode & O_WRONLY) || (omode & O_RDWR);
386
387 return fd;
388 }
389
390 int sys_mkdir(void)
391 {
392 char *path;
393 struct inode *ip;
394
395 begin_trans();
396
397 if(argstr(0, &path) < 0 || (ip = create(path, T_DIR, 0, 0)) == 0){
398 commit_trans();
399 return -1;
400 }
401
402 iunlockput(ip);
403 commit_trans();
404
405 return 0;
406 }
407
408 int sys_mknod(void)
409 {
410 struct inode *ip;
411 char *path;
412 int len;
413 int major, minor;
414
415 begin_trans();
416
417 if((len=argstr(0, &path)) < 0 ||
418 argint(1, &major) < 0 || argint(2, &minor) < 0 ||
419 (ip = create(path, T_DEV, major, minor)) == 0){
420
421 commit_trans();
422 return -1;
423 }
424
425 iunlockput(ip);
426 commit_trans();
427
428 return 0;
429 }
430
431 int sys_chdir(void)
432 {
433 char *path;
434 struct inode *ip;
435
436 if(argstr(0, &path) < 0 || (ip = namei(path)) == 0) {
437 return -1;
438 }
439
440 ilock(ip);
441
442 if(ip->type != T_DIR){
443 iunlockput(ip);
444 return -1;
445 }
446
447 iunlock(ip);
448
449 iput(proc->cwd);
450 proc->cwd = ip;
451
452 return 0;
453 }
454
455 int sys_exec(void)
456 {
457 char *path, *argv[MAXARG];
458 int i;
459 uint uargv, uarg;
460
461 if(argstr(0, &path) < 0 || argint(1, (int*)&uargv) < 0){
462 return -1;
463 }
464
465 memset(argv, 0, sizeof(argv));
466
467 for(i=0;; i++){
468 if(i >= NELEM(argv)) {
469 return -1;
470 }
471
472 if(fetchint(uargv+4*i, (int*)&uarg) < 0) {
473 return -1;
474 }
475
476 if(uarg == 0){
477 argv[i] = 0;
478 break;
479 }
480
481 if(fetchstr(uarg, &argv[i]) < 0) {
482 return -1;
483 }
484 }
485
486 return exec(path, argv);
487 }
488
489 int sys_pipe(void)
490 {
491 int *fd;
492 struct file *rf, *wf;
493 int fd0, fd1;
494
495 if(argptr(0, (void*)&fd, 2*sizeof(fd[0])) < 0) {
496 return -1;
497 }
498
499 if(pipealloc(&rf, &wf) < 0) {
500 return -1;
501 }
502
503 fd0 = -1;
504
505 if((fd0 = fdalloc(rf)) < 0 || (fd1 = fdalloc(wf)) < 0){
506 if(fd0 >= 0) {
507 proc->ofile[fd0] = 0;
508 }
509
510 fileclose(rf);
511 fileclose(wf);
512
513 return -1;
514 }
515
516 fd[0] = fd0;
517 fd[1] = fd1;
518
519 return 0;
520 }