Commit | Line | Data |
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b991bc2d JSP |
1 | /* |
2 | * Copyright (c) 1994 Jan-Simon Pendry | |
3 | * Copyright (c) 1994 | |
4 | * The Regents of the University of California. All rights reserved. | |
5 | * | |
6 | * This code is derived from software contributed to Berkeley by | |
7 | * Jan-Simon Pendry. | |
8 | * | |
9 | * %sccs.include.redist.c% | |
10 | * | |
692a90df | 11 | * @(#)union_subr.c 1.9 (Berkeley) %G% |
b991bc2d JSP |
12 | */ |
13 | ||
14 | #include <sys/param.h> | |
15 | #include <sys/systm.h> | |
16 | #include <sys/time.h> | |
17 | #include <sys/kernel.h> | |
18 | #include <sys/vnode.h> | |
19 | #include <sys/namei.h> | |
20 | #include <sys/malloc.h> | |
81be6ee0 | 21 | #include <sys/file.h> |
3b293975 | 22 | #include <sys/filedesc.h> |
b991bc2d JSP |
23 | #include "union.h" /*<miscfs/union/union.h>*/ |
24 | ||
79f80c71 JSP |
25 | #ifdef DIAGNOSTIC |
26 | #include <sys/proc.h> | |
27 | #endif | |
28 | ||
b991bc2d JSP |
29 | static struct union_node *unhead; |
30 | static int unvplock; | |
31 | ||
32 | int | |
33 | union_init() | |
34 | { | |
35 | ||
36 | unhead = 0; | |
37 | unvplock = 0; | |
38 | } | |
39 | ||
40 | /* | |
41 | * allocate a union_node/vnode pair. the vnode is | |
01dac67e JSP |
42 | * referenced and locked. the new vnode is returned |
43 | * via (vpp). (mp) is the mountpoint of the union filesystem, | |
44 | * (dvp) is the parent directory where the upper layer object | |
45 | * should exist (but doesn't) and (cnp) is the componentname | |
46 | * information which is partially copied to allow the upper | |
47 | * layer object to be created at a later time. (uppervp) | |
48 | * and (lowervp) reference the upper and lower layer objects | |
49 | * being mapped. either, but not both, can be nil. | |
3b293975 JSP |
50 | * the reference is either maintained in the new union_node |
51 | * object which is allocated, or they are vrele'd. | |
b991bc2d JSP |
52 | * |
53 | * all union_nodes are maintained on a singly-linked | |
54 | * list. new nodes are only allocated when they cannot | |
55 | * be found on this list. entries on the list are | |
56 | * removed when the vfs reclaim entry is called. | |
57 | * | |
58 | * a single lock is kept for the entire list. this is | |
59 | * needed because the getnewvnode() function can block | |
60 | * waiting for a vnode to become free, in which case there | |
61 | * may be more than one process trying to get the same | |
62 | * vnode. this lock is only taken if we are going to | |
63 | * call getnewvnode, since the kernel itself is single-threaded. | |
64 | * | |
65 | * if an entry is found on the list, then call vget() to | |
66 | * take a reference. this is done because there may be | |
67 | * zero references to it and so it needs to removed from | |
68 | * the vnode free list. | |
69 | */ | |
70 | int | |
79f80c71 | 71 | union_allocvp(vpp, mp, undvp, dvp, cnp, uppervp, lowervp) |
b991bc2d JSP |
72 | struct vnode **vpp; |
73 | struct mount *mp; | |
79f80c71 | 74 | struct vnode *undvp; |
b991bc2d JSP |
75 | struct vnode *dvp; /* may be null */ |
76 | struct componentname *cnp; /* may be null */ | |
77 | struct vnode *uppervp; /* may be null */ | |
78 | struct vnode *lowervp; /* may be null */ | |
79 | { | |
80 | int error; | |
81 | struct union_node *un; | |
82 | struct union_node **pp; | |
01dac67e JSP |
83 | struct vnode *xlowervp = 0; |
84 | ||
85 | if (uppervp == 0 && lowervp == 0) | |
86 | panic("union: unidentifiable allocation"); | |
87 | ||
88 | if (uppervp && lowervp && (uppervp->v_type != lowervp->v_type)) { | |
89 | xlowervp = lowervp; | |
90 | lowervp = 0; | |
91 | } | |
b991bc2d JSP |
92 | |
93 | loop: | |
94 | for (un = unhead; un != 0; un = un->un_next) { | |
95 | if ((un->un_lowervp == lowervp || | |
96 | un->un_lowervp == 0) && | |
97 | (un->un_uppervp == uppervp || | |
98 | un->un_uppervp == 0) && | |
99 | (UNIONTOV(un)->v_mount == mp)) { | |
79f80c71 | 100 | if (vget(UNIONTOV(un), 0)) |
b991bc2d | 101 | goto loop; |
79f80c71 JSP |
102 | if (UNIONTOV(un) != undvp) |
103 | VOP_LOCK(UNIONTOV(un)); | |
ed5969c8 JSP |
104 | |
105 | /* | |
106 | * Save information about the upper layer. | |
107 | */ | |
79f80c71 JSP |
108 | if (uppervp != un->un_uppervp) { |
109 | if (un->un_uppervp) | |
110 | vrele(un->un_uppervp); | |
111 | un->un_uppervp = uppervp; | |
3b293975 JSP |
112 | } else if (uppervp) { |
113 | vrele(uppervp); | |
79f80c71 | 114 | } |
ed5969c8 JSP |
115 | |
116 | /* | |
117 | * Save information about the lower layer. | |
118 | * This needs to keep track of pathname | |
119 | * and directory information which union_vn_create | |
120 | * might need. | |
121 | */ | |
79f80c71 | 122 | if (lowervp != un->un_lowervp) { |
ed5969c8 | 123 | if (un->un_lowervp) { |
79f80c71 | 124 | vrele(un->un_lowervp); |
ed5969c8 JSP |
125 | free(un->un_path, M_TEMP); |
126 | vrele(un->un_dirvp); | |
127 | } | |
79f80c71 | 128 | un->un_lowervp = lowervp; |
ed5969c8 JSP |
129 | if (cnp && (lowervp != NULLVP) && |
130 | (lowervp->v_type == VREG)) { | |
131 | un->un_hash = cnp->cn_hash; | |
132 | un->un_path = malloc(cnp->cn_namelen+1, | |
133 | M_TEMP, M_WAITOK); | |
134 | bcopy(cnp->cn_nameptr, un->un_path, | |
135 | cnp->cn_namelen); | |
136 | un->un_path[cnp->cn_namelen] = '\0'; | |
137 | VREF(dvp); | |
138 | un->un_dirvp = dvp; | |
139 | } | |
3b293975 JSP |
140 | } else if (lowervp) { |
141 | vrele(lowervp); | |
79f80c71 JSP |
142 | } |
143 | *vpp = UNIONTOV(un); | |
b991bc2d JSP |
144 | return (0); |
145 | } | |
146 | } | |
147 | ||
148 | /* | |
149 | * otherwise lock the vp list while we call getnewvnode | |
150 | * since that can block. | |
151 | */ | |
152 | if (unvplock & UN_LOCKED) { | |
153 | unvplock |= UN_WANT; | |
154 | sleep((caddr_t) &unvplock, PINOD); | |
155 | goto loop; | |
156 | } | |
157 | unvplock |= UN_LOCKED; | |
158 | ||
159 | error = getnewvnode(VT_UNION, mp, union_vnodeop_p, vpp); | |
160 | if (error) | |
161 | goto out; | |
162 | ||
163 | MALLOC((*vpp)->v_data, void *, sizeof(struct union_node), | |
164 | M_TEMP, M_WAITOK); | |
165 | ||
01dac67e JSP |
166 | if (uppervp) |
167 | (*vpp)->v_type = uppervp->v_type; | |
168 | else | |
169 | (*vpp)->v_type = lowervp->v_type; | |
b991bc2d | 170 | un = VTOUNION(*vpp); |
79f80c71 | 171 | un->un_vnode = *vpp; |
b991bc2d | 172 | un->un_next = 0; |
b991bc2d JSP |
173 | un->un_uppervp = uppervp; |
174 | un->un_lowervp = lowervp; | |
15a86f7e | 175 | un->un_openl = 0; |
b991bc2d | 176 | un->un_flags = 0; |
ed5969c8 JSP |
177 | if (cnp && (lowervp != NULLVP) && (lowervp->v_type == VREG)) { |
178 | un->un_hash = cnp->cn_hash; | |
b991bc2d JSP |
179 | un->un_path = malloc(cnp->cn_namelen+1, M_TEMP, M_WAITOK); |
180 | bcopy(cnp->cn_nameptr, un->un_path, cnp->cn_namelen); | |
181 | un->un_path[cnp->cn_namelen] = '\0'; | |
01dac67e JSP |
182 | VREF(dvp); |
183 | un->un_dirvp = dvp; | |
b991bc2d | 184 | } else { |
ed5969c8 | 185 | un->un_hash = 0; |
b991bc2d | 186 | un->un_path = 0; |
01dac67e | 187 | un->un_dirvp = 0; |
b991bc2d JSP |
188 | } |
189 | ||
b991bc2d JSP |
190 | /* add to union vnode list */ |
191 | for (pp = &unhead; *pp; pp = &(*pp)->un_next) | |
192 | continue; | |
193 | *pp = un; | |
194 | ||
79f80c71 JSP |
195 | un->un_flags |= UN_LOCKED; |
196 | ||
197 | #ifdef DIAGNOSTIC | |
198 | un->un_pid = curproc->p_pid; | |
199 | #endif | |
01dac67e JSP |
200 | |
201 | if (xlowervp) | |
202 | vrele(xlowervp); | |
203 | ||
b991bc2d JSP |
204 | out: |
205 | unvplock &= ~UN_LOCKED; | |
206 | ||
207 | if (unvplock & UN_WANT) { | |
208 | unvplock &= ~UN_WANT; | |
209 | wakeup((caddr_t) &unvplock); | |
210 | } | |
211 | ||
b991bc2d JSP |
212 | return (error); |
213 | } | |
214 | ||
215 | int | |
216 | union_freevp(vp) | |
217 | struct vnode *vp; | |
218 | { | |
219 | struct union_node **unpp; | |
220 | struct union_node *un = VTOUNION(vp); | |
221 | ||
222 | for (unpp = &unhead; *unpp != 0; unpp = &(*unpp)->un_next) { | |
223 | if (*unpp == un) { | |
224 | *unpp = un->un_next; | |
225 | break; | |
226 | } | |
227 | } | |
228 | ||
b991bc2d JSP |
229 | FREE(vp->v_data, M_TEMP); |
230 | vp->v_data = 0; | |
231 | return (0); | |
232 | } | |
81be6ee0 JSP |
233 | |
234 | /* | |
235 | * copyfile. copy the vnode (fvp) to the vnode (tvp) | |
236 | * using a sequence of reads and writes. both (fvp) | |
237 | * and (tvp) are locked on entry and exit. | |
238 | */ | |
239 | int | |
240 | union_copyfile(p, cred, fvp, tvp) | |
241 | struct proc *p; | |
242 | struct ucred *cred; | |
243 | struct vnode *fvp; | |
244 | struct vnode *tvp; | |
245 | { | |
246 | char *buf; | |
247 | struct uio uio; | |
248 | struct iovec iov; | |
249 | int error = 0; | |
250 | ||
251 | /* | |
252 | * strategy: | |
253 | * allocate a buffer of size MAXBSIZE. | |
254 | * loop doing reads and writes, keeping track | |
255 | * of the current uio offset. | |
256 | * give up at the first sign of trouble. | |
257 | */ | |
258 | ||
259 | uio.uio_procp = p; | |
260 | uio.uio_segflg = UIO_SYSSPACE; | |
261 | uio.uio_offset = 0; | |
262 | ||
263 | VOP_UNLOCK(fvp); /* XXX */ | |
264 | LEASE_CHECK(fvp, p, cred, LEASE_READ); | |
265 | VOP_LOCK(fvp); /* XXX */ | |
266 | VOP_UNLOCK(tvp); /* XXX */ | |
267 | LEASE_CHECK(tvp, p, cred, LEASE_WRITE); | |
268 | VOP_LOCK(tvp); /* XXX */ | |
269 | ||
270 | buf = malloc(MAXBSIZE, M_TEMP, M_WAITOK); | |
271 | ||
272 | /* ugly loop follows... */ | |
273 | do { | |
274 | off_t offset = uio.uio_offset; | |
275 | ||
276 | uio.uio_iov = &iov; | |
277 | uio.uio_iovcnt = 1; | |
278 | iov.iov_base = buf; | |
279 | iov.iov_len = MAXBSIZE; | |
280 | uio.uio_resid = iov.iov_len; | |
281 | uio.uio_rw = UIO_READ; | |
282 | error = VOP_READ(fvp, &uio, 0, cred); | |
283 | ||
284 | if (error == 0) { | |
285 | uio.uio_iov = &iov; | |
286 | uio.uio_iovcnt = 1; | |
287 | iov.iov_base = buf; | |
288 | iov.iov_len = MAXBSIZE - uio.uio_resid; | |
289 | uio.uio_offset = offset; | |
290 | uio.uio_rw = UIO_WRITE; | |
291 | uio.uio_resid = iov.iov_len; | |
292 | ||
293 | if (uio.uio_resid == 0) | |
294 | break; | |
295 | ||
296 | do { | |
297 | error = VOP_WRITE(tvp, &uio, 0, cred); | |
298 | } while ((uio.uio_resid > 0) && (error == 0)); | |
299 | } | |
300 | ||
301 | } while (error == 0); | |
302 | ||
303 | free(buf, M_TEMP); | |
304 | return (error); | |
305 | } | |
306 | ||
3b293975 JSP |
307 | /* |
308 | * Create a shadow directory in the upper layer. | |
309 | * The new vnode is returned locked. | |
310 | * | |
311 | * (um) points to the union mount structure for access to the | |
312 | * the mounting process's credentials. | |
313 | * (dvp) is the directory in which to create the shadow directory. | |
314 | * it is unlocked on entry and exit. | |
315 | * (cnp) is the componentname to be created. | |
316 | * (vpp) is the returned newly created shadow directory, which | |
317 | * is returned locked. | |
318 | */ | |
319 | int | |
320 | union_mkshadow(um, dvp, cnp, vpp) | |
321 | struct union_mount *um; | |
322 | struct vnode *dvp; | |
323 | struct componentname *cnp; | |
324 | struct vnode **vpp; | |
325 | { | |
326 | int error; | |
327 | struct vattr va; | |
328 | struct proc *p = cnp->cn_proc; | |
329 | struct componentname cn; | |
330 | ||
331 | /* | |
332 | * policy: when creating the shadow directory in the | |
692a90df JSP |
333 | * upper layer, create it owned by the user who did |
334 | * the mount, group from parent directory, and mode | |
335 | * 777 modified by umask (ie mostly identical to the | |
336 | * mkdir syscall). (jsp, kb) | |
3b293975 JSP |
337 | */ |
338 | ||
339 | /* | |
340 | * A new componentname structure must be faked up because | |
341 | * there is no way to know where the upper level cnp came | |
342 | * from or what it is being used for. This must duplicate | |
343 | * some of the work done by NDINIT, some of the work done | |
344 | * by namei, some of the work done by lookup and some of | |
345 | * the work done by VOP_LOOKUP when given a CREATE flag. | |
346 | * Conclusion: Horrible. | |
347 | * | |
348 | * The pathname buffer will be FREEed by VOP_MKDIR. | |
349 | */ | |
350 | cn.cn_pnbuf = malloc(cnp->cn_namelen+1, M_NAMEI, M_WAITOK); | |
ed5969c8 JSP |
351 | bcopy(cnp->cn_nameptr, cn.cn_pnbuf, cnp->cn_namelen); |
352 | cn.cn_pnbuf[cnp->cn_namelen] = '\0'; | |
3b293975 JSP |
353 | |
354 | cn.cn_nameiop = CREATE; | |
355 | cn.cn_flags = (LOCKPARENT|HASBUF|SAVENAME|ISLASTCN); | |
356 | cn.cn_proc = cnp->cn_proc; | |
692a90df | 357 | cn.cn_cred = um->um_cred; |
3b293975 JSP |
358 | cn.cn_nameptr = cn.cn_pnbuf; |
359 | cn.cn_namelen = cnp->cn_namelen; | |
360 | cn.cn_hash = cnp->cn_hash; | |
361 | cn.cn_consume = cnp->cn_consume; | |
362 | ||
ed5969c8 | 363 | VREF(dvp); |
3b293975 JSP |
364 | if (error = relookup(dvp, vpp, &cn)) |
365 | return (error); | |
ed5969c8 | 366 | vrele(dvp); |
3b293975 JSP |
367 | |
368 | if (*vpp) { | |
369 | VOP_ABORTOP(dvp, &cn); | |
370 | VOP_UNLOCK(dvp); | |
371 | vrele(*vpp); | |
372 | *vpp = NULLVP; | |
373 | return (EEXIST); | |
374 | } | |
375 | ||
376 | VATTR_NULL(&va); | |
377 | va.va_type = VDIR; | |
692a90df | 378 | va.va_mode = um->um_cmode; |
3b293975 JSP |
379 | |
380 | /* LEASE_CHECK: dvp is locked */ | |
381 | LEASE_CHECK(dvp, p, p->p_ucred, LEASE_WRITE); | |
382 | ||
383 | VREF(dvp); | |
384 | error = VOP_MKDIR(dvp, vpp, &cn, &va); | |
385 | return (error); | |
386 | } | |
387 | ||
81be6ee0 JSP |
388 | /* |
389 | * union_vn_create: creates and opens a new shadow file | |
390 | * on the upper union layer. this function is similar | |
391 | * in spirit to calling vn_open but it avoids calling namei(). | |
392 | * the problem with calling namei is that a) it locks too many | |
393 | * things, and b) it doesn't start at the "right" directory, | |
394 | * whereas relookup is told where to start. | |
395 | */ | |
396 | int | |
3b293975 | 397 | union_vn_create(vpp, un, p) |
81be6ee0 JSP |
398 | struct vnode **vpp; |
399 | struct union_node *un; | |
81be6ee0 JSP |
400 | struct proc *p; |
401 | { | |
402 | struct vnode *vp; | |
403 | struct ucred *cred = p->p_ucred; | |
404 | struct vattr vat; | |
405 | struct vattr *vap = &vat; | |
406 | int fmode = FFLAGS(O_WRONLY|O_CREAT|O_TRUNC|O_EXCL); | |
407 | int error; | |
ed5969c8 | 408 | int cmode = UN_FILEMODE & ~p->p_fd->fd_cmask; |
81be6ee0 JSP |
409 | char *cp; |
410 | struct componentname cn; | |
411 | ||
412 | *vpp = NULLVP; | |
413 | ||
692a90df JSP |
414 | /* |
415 | * Build a new componentname structure (for the same | |
416 | * reasons outlines in union_mkshadow). | |
417 | * The difference here is that the file is owned by | |
418 | * the current user, rather than by the person who | |
419 | * did the mount, since the current user needs to be | |
420 | * able to write the file (that's why it is being | |
421 | * copied in the first place). | |
422 | */ | |
81be6ee0 JSP |
423 | cn.cn_namelen = strlen(un->un_path); |
424 | cn.cn_pnbuf = (caddr_t) malloc(cn.cn_namelen, M_NAMEI, M_WAITOK); | |
425 | bcopy(un->un_path, cn.cn_pnbuf, cn.cn_namelen+1); | |
426 | cn.cn_nameiop = CREATE; | |
427 | cn.cn_flags = (LOCKLEAF|LOCKPARENT|HASBUF|SAVENAME|ISLASTCN); | |
428 | cn.cn_proc = p; | |
429 | cn.cn_cred = p->p_ucred; | |
430 | cn.cn_nameptr = cn.cn_pnbuf; | |
ed5969c8 | 431 | cn.cn_hash = un->un_hash; |
81be6ee0 JSP |
432 | cn.cn_consume = 0; |
433 | ||
ed5969c8 | 434 | VREF(un->un_dirvp); |
81be6ee0 JSP |
435 | if (error = relookup(un->un_dirvp, &vp, &cn)) |
436 | return (error); | |
ed5969c8 JSP |
437 | vrele(un->un_dirvp); |
438 | ||
81be6ee0 | 439 | if (vp == NULLVP) { |
692a90df JSP |
440 | /* |
441 | * Good - there was no race to create the file | |
442 | * so go ahead and create it. The permissions | |
443 | * on the file will be 0666 modified by the | |
444 | * current user's umask. Access to the file, while | |
445 | * it is unioned, will require access to the top *and* | |
446 | * bottom files. Access when not unioned will simply | |
447 | * require access to the top-level file. | |
448 | * TODO: confirm choice of access permissions. | |
449 | */ | |
81be6ee0 JSP |
450 | VATTR_NULL(vap); |
451 | vap->va_type = VREG; | |
452 | vap->va_mode = cmode; | |
453 | LEASE_CHECK(un->un_dirvp, p, cred, LEASE_WRITE); | |
454 | if (error = VOP_CREATE(un->un_dirvp, &vp, | |
455 | &cn, vap)) | |
456 | return (error); | |
457 | } else { | |
458 | VOP_ABORTOP(un->un_dirvp, &cn); | |
459 | if (un->un_dirvp == vp) | |
460 | vrele(un->un_dirvp); | |
461 | else | |
462 | vput(vp); | |
463 | error = EEXIST; | |
464 | goto bad; | |
465 | } | |
466 | ||
467 | if (vp->v_type != VREG) { | |
468 | error = EOPNOTSUPP; | |
469 | goto bad; | |
470 | } | |
471 | ||
472 | VOP_UNLOCK(vp); /* XXX */ | |
473 | LEASE_CHECK(vp, p, cred, LEASE_WRITE); | |
474 | VOP_LOCK(vp); /* XXX */ | |
475 | VATTR_NULL(vap); | |
476 | vap->va_size = 0; | |
477 | if (error = VOP_SETATTR(vp, vap, cred, p)) | |
478 | goto bad; | |
479 | ||
480 | if (error = VOP_OPEN(vp, fmode, cred, p)) | |
481 | goto bad; | |
482 | ||
483 | vp->v_writecount++; | |
484 | *vpp = vp; | |
485 | return (0); | |
486 | bad: | |
487 | vput(vp); | |
488 | return (error); | |
489 | } | |
ed5969c8 JSP |
490 | |
491 | int | |
15a86f7e | 492 | union_vn_close(vp, fmode, cred, p) |
ed5969c8 JSP |
493 | struct vnode *vp; |
494 | int fmode; | |
15a86f7e JSP |
495 | struct ucred *cred; |
496 | struct proc *p; | |
ed5969c8 JSP |
497 | { |
498 | if (fmode & FWRITE) | |
499 | --vp->v_writecount; | |
500 | return (VOP_CLOSE(vp, fmode)); | |
501 | } | |
502 | ||
503 | void | |
504 | union_removed_upper(un) | |
505 | struct union_node *un; | |
506 | { | |
507 | vrele(un->un_uppervp); | |
508 | un->un_uppervp = NULLVP; | |
509 | } | |
15a86f7e JSP |
510 | |
511 | struct vnode * | |
512 | union_lowervp(vp) | |
513 | struct vnode *vp; | |
514 | { | |
515 | struct union_node *un = VTOUNION(vp); | |
516 | ||
517 | if (un->un_lowervp && (vp->v_type == un->un_lowervp->v_type)) { | |
518 | if (vget(un->un_lowervp, 0)) | |
519 | return (NULLVP); | |
520 | } | |
521 | ||
522 | return (un->un_lowervp); | |
523 | } |