Mercurial > hg > CbC > CbC_xv6
annotate src/sysfile.cbc @ 113:ef44d384ad9d
rollback rev 52
| author | anatofuz <anatofuz@cr.ie.u-ryukyu.ac.jp> |
|---|---|
| date | Mon, 02 Dec 2019 11:17:04 +0900 |
| parents | 7d0ec88cdd22 |
| children | 8c12438a9827 |
| rev | line source |
|---|---|
| 0 | 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 | |
|
92
bc5bcfd2f6d6
rename CbCFile to CbCSysFile
anatofuz <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
91
diff
changeset
|
17 #define __ncode __code |
|
bc5bcfd2f6d6
rename CbCFile to CbCSysFile
anatofuz <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
91
diff
changeset
|
18 |
| 0 | 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 | |
| 113 | 79 __ncode cbc_read(__code (*next)(int ret)){ |
| 24 | 80 struct file *f; |
| 81 int n; | |
| 82 char *p; | |
| 113 | 83 |
| 24 | 84 if(argfd(0, 0, &f) < 0 || argint(2, &n) < 0 || argptr(1, &p, n) < 0) { |
| 113 | 85 goto next(-1); |
| 24 | 86 } |
| 113 | 87 goto cbc_fileread(f, p, n, next); |
| 88 | 88 } |
| 89 | |
| 0 | 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. | |
|
92
bc5bcfd2f6d6
rename CbCFile to CbCSysFile
anatofuz <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
91
diff
changeset
|
319 dp->nlink++; // for ".." |
|
bc5bcfd2f6d6
rename CbCFile to CbCSysFile
anatofuz <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
91
diff
changeset
|
320 iupdate(dp); |
| 0 | 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 } |