Mercurial > hg > Members > menikon > CbC_xv6
annotate src/sysfile.cbc @ 323:f0b337cb6024 default tip
use goto err->panic
| author | anatofuz <anatofuz@cr.ie.u-ryukyu.ac.jp> |
|---|---|
| date | Sat, 08 Feb 2020 20:37:42 +0900 |
| parents | 8c12438a9827 |
| children |
| 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 | |
| 174 | 17 //data_gear "inode.h" |
| 18 | |
|
92
bc5bcfd2f6d6
rename CbCFile to CbCSysFile
anatofuz <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
91
diff
changeset
|
19 #define __ncode __code |
|
bc5bcfd2f6d6
rename CbCFile to CbCSysFile
anatofuz <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
91
diff
changeset
|
20 |
| 0 | 21 // Fetch the nth word-sized system call argument as a file descriptor |
| 22 // and return both the descriptor and the corresponding struct file. | |
| 23 static int argfd(int n, int *pfd, struct file **pf) | |
| 24 { | |
| 25 int fd; | |
| 26 struct file *f; | |
| 27 | |
| 28 if(argint(n, &fd) < 0) { | |
| 29 return -1; | |
| 30 } | |
| 31 | |
| 32 if(fd < 0 || fd >= NOFILE || (f=proc->ofile[fd]) == 0) { | |
| 33 return -1; | |
| 34 } | |
| 35 | |
| 36 if(pfd) { | |
| 37 *pfd = fd; | |
| 38 } | |
| 39 | |
| 40 if(pf) { | |
| 41 *pf = f; | |
| 42 } | |
| 43 | |
| 44 return 0; | |
| 45 } | |
| 46 | |
| 47 // Allocate a file descriptor for the given file. | |
| 48 // Takes over file reference from caller on success. | |
| 49 static int fdalloc(struct file *f) | |
| 50 { | |
| 51 int fd; | |
| 52 | |
| 53 for(fd = 0; fd < NOFILE; fd++){ | |
| 54 if(proc->ofile[fd] == 0){ | |
| 55 proc->ofile[fd] = f; | |
| 56 return fd; | |
| 57 } | |
| 58 } | |
| 59 | |
| 60 return -1; | |
| 61 } | |
| 62 | |
| 63 int sys_dup(void) | |
| 64 { | |
| 65 struct file *f; | |
| 66 int fd; | |
| 67 | |
| 68 if(argfd(0, 0, &f) < 0) { | |
| 69 return -1; | |
| 70 } | |
| 71 | |
| 72 if((fd=fdalloc(f)) < 0) { | |
| 73 return -1; | |
| 74 } | |
| 75 | |
| 76 filedup(f); | |
| 77 | |
| 78 return fd; | |
| 79 } | |
| 80 | |
| 113 | 81 __ncode cbc_read(__code (*next)(int ret)){ |
| 24 | 82 struct file *f; |
| 83 int n; | |
| 84 char *p; | |
| 113 | 85 |
| 24 | 86 if(argfd(0, 0, &f) < 0 || argint(2, &n) < 0 || argptr(1, &p, n) < 0) { |
| 113 | 87 goto next(-1); |
| 24 | 88 } |
| 113 | 89 goto cbc_fileread(f, p, n, next); |
| 88 | 90 } |
| 91 | |
| 0 | 92 int sys_read(void) |
| 93 { | |
| 94 struct file *f; | |
| 95 int n; | |
| 96 char *p; | |
| 97 | |
| 98 if(argfd(0, 0, &f) < 0 || argint(2, &n) < 0 || argptr(1, &p, n) < 0) { | |
| 99 return -1; | |
| 100 } | |
| 101 | |
| 102 return fileread(f, p, n); | |
| 103 } | |
| 104 | |
| 105 int sys_write(void) | |
| 106 { | |
| 107 struct file *f; | |
| 108 int n; | |
| 109 char *p; | |
| 110 | |
| 111 if(argfd(0, 0, &f) < 0 || argint(2, &n) < 0 || argptr(1, &p, n) < 0) { | |
| 112 return -1; | |
| 113 } | |
| 114 | |
| 115 return filewrite(f, p, n); | |
| 116 } | |
| 117 | |
| 118 int sys_close(void) | |
| 119 { | |
| 120 int fd; | |
| 121 struct file *f; | |
| 122 | |
| 123 if(argfd(0, &fd, &f) < 0) { | |
| 124 return -1; | |
| 125 } | |
| 126 | |
| 127 proc->ofile[fd] = 0; | |
| 128 fileclose(f); | |
| 129 | |
| 130 return 0; | |
| 131 } | |
| 132 | |
| 133 int sys_fstat(void) | |
| 134 { | |
| 135 struct file *f; | |
| 136 struct stat *st; | |
| 137 | |
| 138 if(argfd(0, 0, &f) < 0 || argptr(1, (void*)&st, sizeof(*st)) < 0) { | |
| 139 return -1; | |
| 140 } | |
| 141 | |
| 142 return filestat(f, st); | |
| 143 } | |
| 144 | |
| 145 // Create the path new as a link to the same inode as old. | |
| 146 int sys_link(void) | |
| 147 { | |
| 148 char name[DIRSIZ], *new, *old; | |
| 149 struct inode *dp, *ip; | |
| 150 | |
| 151 if(argstr(0, &old) < 0 || argstr(1, &new) < 0) { | |
| 152 return -1; | |
| 153 } | |
| 154 | |
| 155 if((ip = namei(old)) == 0) { | |
| 156 return -1; | |
| 157 } | |
| 158 | |
| 159 begin_trans(); | |
| 160 | |
| 161 ilock(ip); | |
| 162 | |
| 163 if(ip->type == T_DIR){ | |
| 164 iunlockput(ip); | |
| 165 commit_trans(); | |
| 166 return -1; | |
| 167 } | |
| 168 | |
| 169 ip->nlink++; | |
| 170 iupdate(ip); | |
| 171 iunlock(ip); | |
| 172 | |
| 173 if((dp = nameiparent(new, name)) == 0) { | |
| 174 goto bad; | |
| 175 } | |
| 176 | |
| 177 ilock(dp); | |
| 178 | |
| 179 if(dp->dev != ip->dev || dirlink(dp, name, ip->inum) < 0){ | |
| 180 iunlockput(dp); | |
| 181 goto bad; | |
| 182 } | |
| 183 | |
| 184 iunlockput(dp); | |
| 185 iput(ip); | |
| 186 | |
| 187 commit_trans(); | |
| 188 | |
| 189 return 0; | |
| 190 | |
| 191 bad: | |
| 192 ilock(ip); | |
| 193 ip->nlink--; | |
| 194 iupdate(ip); | |
| 195 iunlockput(ip); | |
| 196 commit_trans(); | |
| 197 return -1; | |
| 198 } | |
| 199 | |
| 200 // Is the directory dp empty except for "." and ".." ? | |
| 201 static int isdirempty(struct inode *dp) | |
| 202 { | |
| 203 int off; | |
| 204 struct dirent de; | |
| 205 | |
| 206 for(off=2*sizeof(de); off<dp->size; off+=sizeof(de)){ | |
| 207 if(readi(dp, (char*)&de, off, sizeof(de)) != sizeof(de)) { | |
| 208 panic("isdirempty: readi"); | |
| 209 } | |
| 210 | |
| 211 if(de.inum != 0) { | |
| 212 return 0; | |
| 213 } | |
| 214 } | |
| 215 return 1; | |
| 216 } | |
| 217 | |
| 218 //PAGEBREAK! | |
| 219 int sys_unlink(void) | |
| 220 { | |
| 221 struct inode *ip, *dp; | |
| 222 struct dirent de; | |
| 223 char name[DIRSIZ], *path; | |
| 224 uint off; | |
| 225 | |
| 226 if(argstr(0, &path) < 0) { | |
| 227 return -1; | |
| 228 } | |
| 229 | |
| 230 if((dp = nameiparent(path, name)) == 0) { | |
| 231 return -1; | |
| 232 } | |
| 233 | |
| 234 begin_trans(); | |
| 235 | |
| 236 ilock(dp); | |
| 237 | |
| 238 // Cannot unlink "." or "..". | |
| 239 if(namecmp(name, ".") == 0 || namecmp(name, "..") == 0) { | |
| 240 goto bad; | |
| 241 } | |
| 242 | |
| 243 if((ip = dirlookup(dp, name, &off)) == 0) { | |
| 244 goto bad; | |
| 245 } | |
| 246 | |
| 247 ilock(ip); | |
| 248 | |
| 249 if(ip->nlink < 1) { | |
| 250 panic("unlink: nlink < 1"); | |
| 251 } | |
| 252 | |
| 253 if(ip->type == T_DIR && !isdirempty(ip)){ | |
| 254 iunlockput(ip); | |
| 255 goto bad; | |
| 256 } | |
| 257 | |
| 258 memset(&de, 0, sizeof(de)); | |
| 259 | |
| 260 if(writei(dp, (char*)&de, off, sizeof(de)) != sizeof(de)) { | |
| 261 panic("unlink: writei"); | |
| 262 } | |
| 263 | |
| 264 if(ip->type == T_DIR){ | |
| 265 dp->nlink--; | |
| 266 iupdate(dp); | |
| 267 } | |
| 268 | |
| 269 iunlockput(dp); | |
| 270 | |
| 271 ip->nlink--; | |
| 272 iupdate(ip); | |
| 273 iunlockput(ip); | |
| 274 | |
| 275 commit_trans(); | |
| 276 | |
| 277 return 0; | |
| 278 | |
| 279 bad: | |
| 280 iunlockput(dp); | |
| 281 commit_trans(); | |
| 282 return -1; | |
| 283 } | |
| 284 | |
| 285 static struct inode* create(char *path, short type, short major, short minor) | |
| 286 { | |
| 287 uint off; | |
| 288 struct inode *ip, *dp; | |
| 289 char name[DIRSIZ]; | |
| 290 | |
| 291 if((dp = nameiparent(path, name)) == 0) { | |
| 292 return 0; | |
| 293 } | |
| 294 | |
| 295 ilock(dp); | |
| 296 | |
| 297 if((ip = dirlookup(dp, name, &off)) != 0){ | |
| 298 iunlockput(dp); | |
| 299 ilock(ip); | |
| 300 | |
| 301 if(type == T_FILE && ip->type == T_FILE) { | |
| 302 return ip; | |
| 303 } | |
| 304 | |
| 305 iunlockput(ip); | |
| 306 | |
| 307 return 0; | |
| 308 } | |
| 309 | |
| 310 if((ip = ialloc(dp->dev, type)) == 0) { | |
| 311 panic("create: ialloc"); | |
| 312 } | |
| 313 | |
| 314 ilock(ip); | |
| 315 ip->major = major; | |
| 316 ip->minor = minor; | |
| 317 ip->nlink = 1; | |
| 318 iupdate(ip); | |
| 319 | |
| 320 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
|
321 dp->nlink++; // for ".." |
|
bc5bcfd2f6d6
rename CbCFile to CbCSysFile
anatofuz <anatofuz@cr.ie.u-ryukyu.ac.jp>
parents:
91
diff
changeset
|
322 iupdate(dp); |
| 0 | 323 |
| 324 // No ip->nlink++ for ".": avoid cyclic ref count. | |
| 325 if(dirlink(ip, ".", ip->inum) < 0 || dirlink(ip, "..", dp->inum) < 0) { | |
| 326 panic("create dots"); | |
| 327 } | |
| 328 } | |
| 329 | |
| 330 if(dirlink(dp, name, ip->inum) < 0) { | |
| 331 panic("create: dirlink"); | |
| 332 } | |
| 333 | |
| 334 iunlockput(dp); | |
| 335 | |
| 336 return ip; | |
| 337 } | |
| 338 | |
| 339 int sys_open(void) | |
| 340 { | |
| 341 char *path; | |
| 342 int fd, omode; | |
| 343 struct file *f; | |
| 344 struct inode *ip; | |
| 345 | |
| 346 if(argstr(0, &path) < 0 || argint(1, &omode) < 0) { | |
| 347 return -1; | |
| 348 } | |
| 349 | |
| 350 if(omode & O_CREATE){ | |
| 351 begin_trans(); | |
| 352 ip = create(path, T_FILE, 0, 0); | |
| 353 commit_trans(); | |
| 354 | |
| 355 if(ip == 0) { | |
| 356 return -1; | |
| 357 } | |
| 358 | |
| 359 } else { | |
| 360 if((ip = namei(path)) == 0) { | |
| 361 return -1; | |
| 362 } | |
| 363 | |
| 364 ilock(ip); | |
| 365 | |
| 366 if(ip->type == T_DIR && omode != O_RDONLY){ | |
| 367 iunlockput(ip); | |
| 368 return -1; | |
| 369 } | |
| 370 } | |
| 371 | |
| 372 if((f = filealloc()) == 0 || (fd = fdalloc(f)) < 0){ | |
| 373 if(f) { | |
| 374 fileclose(f); | |
| 375 } | |
| 376 | |
| 377 iunlockput(ip); | |
| 378 return -1; | |
| 379 } | |
| 380 | |
| 381 iunlock(ip); | |
| 382 | |
| 383 f->type = FD_INODE; | |
| 384 f->ip = ip; | |
| 385 f->off = 0; | |
| 386 f->readable = !(omode & O_WRONLY); | |
| 387 f->writable = (omode & O_WRONLY) || (omode & O_RDWR); | |
| 388 | |
| 389 return fd; | |
| 390 } | |
| 391 | |
| 392 int sys_mkdir(void) | |
| 393 { | |
| 394 char *path; | |
| 395 struct inode *ip; | |
| 396 | |
| 397 begin_trans(); | |
| 398 | |
| 399 if(argstr(0, &path) < 0 || (ip = create(path, T_DIR, 0, 0)) == 0){ | |
| 400 commit_trans(); | |
| 401 return -1; | |
| 402 } | |
| 403 | |
| 404 iunlockput(ip); | |
| 405 commit_trans(); | |
| 406 | |
| 407 return 0; | |
| 408 } | |
| 409 | |
| 410 int sys_mknod(void) | |
| 411 { | |
| 412 struct inode *ip; | |
| 413 char *path; | |
| 414 int len; | |
| 415 int major, minor; | |
| 416 | |
| 417 begin_trans(); | |
| 418 | |
| 419 if((len=argstr(0, &path)) < 0 || | |
| 420 argint(1, &major) < 0 || argint(2, &minor) < 0 || | |
| 421 (ip = create(path, T_DEV, major, minor)) == 0){ | |
| 422 | |
| 423 commit_trans(); | |
| 424 return -1; | |
| 425 } | |
| 426 | |
| 427 iunlockput(ip); | |
| 428 commit_trans(); | |
| 429 | |
| 430 return 0; | |
| 431 } | |
| 432 | |
| 433 int sys_chdir(void) | |
| 434 { | |
| 435 char *path; | |
| 436 struct inode *ip; | |
| 437 | |
| 438 if(argstr(0, &path) < 0 || (ip = namei(path)) == 0) { | |
| 439 return -1; | |
| 440 } | |
| 441 | |
| 442 ilock(ip); | |
| 443 | |
| 444 if(ip->type != T_DIR){ | |
| 445 iunlockput(ip); | |
| 446 return -1; | |
| 447 } | |
| 448 | |
| 449 iunlock(ip); | |
| 450 | |
| 451 iput(proc->cwd); | |
| 452 proc->cwd = ip; | |
| 453 | |
| 454 return 0; | |
| 455 } | |
| 456 | |
| 457 int sys_exec(void) | |
| 458 { | |
| 459 char *path, *argv[MAXARG]; | |
| 460 int i; | |
| 461 uint uargv, uarg; | |
| 462 | |
| 463 if(argstr(0, &path) < 0 || argint(1, (int*)&uargv) < 0){ | |
| 464 return -1; | |
| 465 } | |
| 466 | |
| 467 memset(argv, 0, sizeof(argv)); | |
| 468 | |
| 469 for(i=0;; i++){ | |
| 470 if(i >= NELEM(argv)) { | |
| 471 return -1; | |
| 472 } | |
| 473 | |
| 474 if(fetchint(uargv+4*i, (int*)&uarg) < 0) { | |
| 475 return -1; | |
| 476 } | |
| 477 | |
| 478 if(uarg == 0){ | |
| 479 argv[i] = 0; | |
| 480 break; | |
| 481 } | |
| 482 | |
| 483 if(fetchstr(uarg, &argv[i]) < 0) { | |
| 484 return -1; | |
| 485 } | |
| 486 } | |
| 487 | |
| 488 return exec(path, argv); | |
| 489 } | |
| 490 | |
| 491 int sys_pipe(void) | |
| 492 { | |
| 493 int *fd; | |
| 494 struct file *rf, *wf; | |
| 495 int fd0, fd1; | |
| 496 | |
| 497 if(argptr(0, (void*)&fd, 2*sizeof(fd[0])) < 0) { | |
| 498 return -1; | |
| 499 } | |
| 500 | |
| 501 if(pipealloc(&rf, &wf) < 0) { | |
| 502 return -1; | |
| 503 } | |
| 504 | |
| 505 fd0 = -1; | |
| 506 | |
| 507 if((fd0 = fdalloc(rf)) < 0 || (fd1 = fdalloc(wf)) < 0){ | |
| 508 if(fd0 >= 0) { | |
| 509 proc->ofile[fd0] = 0; | |
| 510 } | |
| 511 | |
| 512 fileclose(rf); | |
| 513 fileclose(wf); | |
| 514 | |
| 515 return -1; | |
| 516 } | |
| 517 | |
| 518 fd[0] = fd0; | |
| 519 fd[1] = fd1; | |
| 520 | |
| 521 return 0; | |
| 522 } |