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1 | /* | |
2 | * linux/ipc/shm.c | |
3 | * Copyright (C) 1992, 1993 Krishna Balasubramanian | |
4 | * Many improvements/fixes by Bruno Haible. | |
5 | * Replaced `struct shm_desc' by `struct vm_area_struct', July 1994. | |
6 | * Fixed the shm swap deallocation (shm_unuse()), August 1998 Andrea Arcangeli. | |
7 | * | |
8 | * /proc/sysvipc/shm support (c) 1999 Dragos Acostachioaie <dragos@iname.com> | |
9 | * BIGMEM support, Andrea Arcangeli <andrea@suse.de> | |
10 | * SMP thread shm, Jean-Luc Boyard <jean-luc.boyard@siemens.fr> | |
11 | * HIGHMEM support, Ingo Molnar <mingo@redhat.com> | |
12 | * Make shmmax, shmall, shmmni sysctl'able, Christoph Rohland <cr@sap.com> | |
13 | * Shared /dev/zero support, Kanoj Sarcar <kanoj@sgi.com> | |
14 | * Move the mm functionality over to mm/shmem.c, Christoph Rohland <cr@sap.com> | |
15 | * | |
16 | * support for audit of ipc object properties and permission changes | |
17 | * Dustin Kirkland <dustin.kirkland@us.ibm.com> | |
18 | * | |
19 | * namespaces support | |
20 | * OpenVZ, SWsoft Inc. | |
21 | * Pavel Emelianov <xemul@openvz.org> | |
22 | */ | |
23 | ||
24 | #include <linux/slab.h> | |
25 | #include <linux/mm.h> | |
26 | #include <linux/hugetlb.h> | |
27 | #include <linux/shm.h> | |
28 | #include <linux/init.h> | |
29 | #include <linux/file.h> | |
30 | #include <linux/mman.h> | |
31 | #include <linux/shmem_fs.h> | |
32 | #include <linux/security.h> | |
33 | #include <linux/syscalls.h> | |
34 | #include <linux/audit.h> | |
35 | #include <linux/capability.h> | |
36 | #include <linux/ptrace.h> | |
37 | #include <linux/seq_file.h> | |
38 | #include <linux/mutex.h> | |
39 | #include <linux/nsproxy.h> | |
40 | #include <linux/mount.h> | |
41 | ||
42 | #include <asm/uaccess.h> | |
43 | ||
44 | #include "util.h" | |
45 | ||
46 | struct shm_file_data { | |
47 | int id; | |
48 | struct ipc_namespace *ns; | |
49 | struct file *file; | |
50 | const struct vm_operations_struct *vm_ops; | |
51 | }; | |
52 | ||
53 | #define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data)) | |
54 | ||
55 | static const struct file_operations shm_file_operations; | |
56 | static struct vm_operations_struct shm_vm_ops; | |
57 | ||
58 | static struct ipc_ids init_shm_ids; | |
59 | ||
60 | #define shm_ids(ns) (*((ns)->ids[IPC_SHM_IDS])) | |
61 | ||
62 | #define shm_lock(ns, id) \ | |
63 | ((struct shmid_kernel*)ipc_lock(&shm_ids(ns),id)) | |
64 | #define shm_unlock(shp) \ | |
65 | ipc_unlock(&(shp)->shm_perm) | |
66 | #define shm_get(ns, id) \ | |
67 | ((struct shmid_kernel*)ipc_get(&shm_ids(ns),id)) | |
68 | #define shm_buildid(ns, id, seq) \ | |
69 | ipc_buildid(&shm_ids(ns), id, seq) | |
70 | ||
71 | static int newseg(struct ipc_namespace *, struct ipc_params *); | |
72 | static void shm_open(struct vm_area_struct *vma); | |
73 | static void shm_close(struct vm_area_struct *vma); | |
74 | static void shm_destroy (struct ipc_namespace *ns, struct shmid_kernel *shp); | |
75 | #ifdef CONFIG_PROC_FS | |
76 | static int sysvipc_shm_proc_show(struct seq_file *s, void *it); | |
77 | #endif | |
78 | ||
79 | static void __shm_init_ns(struct ipc_namespace *ns, struct ipc_ids *ids) | |
80 | { | |
81 | ns->ids[IPC_SHM_IDS] = ids; | |
82 | ns->shm_ctlmax = SHMMAX; | |
83 | ns->shm_ctlall = SHMALL; | |
84 | ns->shm_ctlmni = SHMMNI; | |
85 | ns->shm_tot = 0; | |
86 | ipc_init_ids(ids); | |
87 | } | |
88 | ||
89 | static void do_shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *shp) | |
90 | { | |
91 | if (shp->shm_nattch){ | |
92 | shp->shm_perm.mode |= SHM_DEST; | |
93 | /* Do not find it any more */ | |
94 | shp->shm_perm.key = IPC_PRIVATE; | |
95 | shm_unlock(shp); | |
96 | } else | |
97 | shm_destroy(ns, shp); | |
98 | } | |
99 | ||
100 | int shm_init_ns(struct ipc_namespace *ns) | |
101 | { | |
102 | struct ipc_ids *ids; | |
103 | ||
104 | ids = kmalloc(sizeof(struct ipc_ids), GFP_KERNEL); | |
105 | if (ids == NULL) | |
106 | return -ENOMEM; | |
107 | ||
108 | __shm_init_ns(ns, ids); | |
109 | return 0; | |
110 | } | |
111 | ||
112 | void shm_exit_ns(struct ipc_namespace *ns) | |
113 | { | |
114 | struct shmid_kernel *shp; | |
115 | int next_id; | |
116 | int total, in_use; | |
117 | ||
118 | mutex_lock(&shm_ids(ns).mutex); | |
119 | ||
120 | in_use = shm_ids(ns).in_use; | |
121 | ||
122 | for (total = 0, next_id = 0; total < in_use; next_id++) { | |
123 | shp = idr_find(&shm_ids(ns).ipcs_idr, next_id); | |
124 | if (shp == NULL) | |
125 | continue; | |
126 | ipc_lock_by_ptr(&shp->shm_perm); | |
127 | do_shm_rmid(ns, shp); | |
128 | total++; | |
129 | } | |
130 | mutex_unlock(&shm_ids(ns).mutex); | |
131 | ||
132 | kfree(ns->ids[IPC_SHM_IDS]); | |
133 | ns->ids[IPC_SHM_IDS] = NULL; | |
134 | } | |
135 | ||
136 | void __init shm_init (void) | |
137 | { | |
138 | __shm_init_ns(&init_ipc_ns, &init_shm_ids); | |
139 | ipc_init_proc_interface("sysvipc/shm", | |
140 | " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime\n", | |
141 | IPC_SHM_IDS, sysvipc_shm_proc_show); | |
142 | } | |
143 | ||
144 | static inline int shm_checkid(struct ipc_namespace *ns, | |
145 | struct shmid_kernel *s, int id) | |
146 | { | |
147 | if (ipc_checkid(&shm_ids(ns), &s->shm_perm, id)) | |
148 | return -EIDRM; | |
149 | return 0; | |
150 | } | |
151 | ||
152 | static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s) | |
153 | { | |
154 | ipc_rmid(&shm_ids(ns), &s->shm_perm); | |
155 | } | |
156 | ||
157 | static inline int shm_addid(struct ipc_namespace *ns, struct shmid_kernel *shp) | |
158 | { | |
159 | return ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni); | |
160 | } | |
161 | ||
162 | ||
163 | ||
164 | /* This is called by fork, once for every shm attach. */ | |
165 | static void shm_open(struct vm_area_struct *vma) | |
166 | { | |
167 | struct file *file = vma->vm_file; | |
168 | struct shm_file_data *sfd = shm_file_data(file); | |
169 | struct shmid_kernel *shp; | |
170 | ||
171 | shp = shm_lock(sfd->ns, sfd->id); | |
172 | BUG_ON(!shp); | |
173 | shp->shm_atim = get_seconds(); | |
174 | shp->shm_lprid = task_tgid_vnr(current); | |
175 | shp->shm_nattch++; | |
176 | shm_unlock(shp); | |
177 | } | |
178 | ||
179 | /* | |
180 | * shm_destroy - free the struct shmid_kernel | |
181 | * | |
182 | * @shp: struct to free | |
183 | * | |
184 | * It has to be called with shp and shm_ids.mutex locked, | |
185 | * but returns with shp unlocked and freed. | |
186 | */ | |
187 | static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp) | |
188 | { | |
189 | ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
190 | shm_rmid(ns, shp); | |
191 | shm_unlock(shp); | |
192 | if (!is_file_hugepages(shp->shm_file)) | |
193 | shmem_lock(shp->shm_file, 0, shp->mlock_user); | |
194 | else | |
195 | user_shm_unlock(shp->shm_file->f_path.dentry->d_inode->i_size, | |
196 | shp->mlock_user); | |
197 | fput (shp->shm_file); | |
198 | security_shm_free(shp); | |
199 | ipc_rcu_putref(shp); | |
200 | } | |
201 | ||
202 | /* | |
203 | * remove the attach descriptor vma. | |
204 | * free memory for segment if it is marked destroyed. | |
205 | * The descriptor has already been removed from the current->mm->mmap list | |
206 | * and will later be kfree()d. | |
207 | */ | |
208 | static void shm_close(struct vm_area_struct *vma) | |
209 | { | |
210 | struct file * file = vma->vm_file; | |
211 | struct shm_file_data *sfd = shm_file_data(file); | |
212 | struct shmid_kernel *shp; | |
213 | struct ipc_namespace *ns = sfd->ns; | |
214 | ||
215 | mutex_lock(&shm_ids(ns).mutex); | |
216 | /* remove from the list of attaches of the shm segment */ | |
217 | shp = shm_lock(ns, sfd->id); | |
218 | BUG_ON(!shp); | |
219 | shp->shm_lprid = task_tgid_vnr(current); | |
220 | shp->shm_dtim = get_seconds(); | |
221 | shp->shm_nattch--; | |
222 | if(shp->shm_nattch == 0 && | |
223 | shp->shm_perm.mode & SHM_DEST) | |
224 | shm_destroy(ns, shp); | |
225 | else | |
226 | shm_unlock(shp); | |
227 | mutex_unlock(&shm_ids(ns).mutex); | |
228 | } | |
229 | ||
230 | static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf) | |
231 | { | |
232 | struct file *file = vma->vm_file; | |
233 | struct shm_file_data *sfd = shm_file_data(file); | |
234 | ||
235 | return sfd->vm_ops->fault(vma, vmf); | |
236 | } | |
237 | ||
238 | #ifdef CONFIG_NUMA | |
239 | static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new) | |
240 | { | |
241 | struct file *file = vma->vm_file; | |
242 | struct shm_file_data *sfd = shm_file_data(file); | |
243 | int err = 0; | |
244 | if (sfd->vm_ops->set_policy) | |
245 | err = sfd->vm_ops->set_policy(vma, new); | |
246 | return err; | |
247 | } | |
248 | ||
249 | static struct mempolicy *shm_get_policy(struct vm_area_struct *vma, | |
250 | unsigned long addr) | |
251 | { | |
252 | struct file *file = vma->vm_file; | |
253 | struct shm_file_data *sfd = shm_file_data(file); | |
254 | struct mempolicy *pol = NULL; | |
255 | ||
256 | if (sfd->vm_ops->get_policy) | |
257 | pol = sfd->vm_ops->get_policy(vma, addr); | |
258 | else if (vma->vm_policy) | |
259 | pol = vma->vm_policy; | |
260 | else | |
261 | pol = current->mempolicy; | |
262 | return pol; | |
263 | } | |
264 | #endif | |
265 | ||
266 | static int shm_mmap(struct file * file, struct vm_area_struct * vma) | |
267 | { | |
268 | struct shm_file_data *sfd = shm_file_data(file); | |
269 | int ret; | |
270 | ||
271 | ret = sfd->file->f_op->mmap(sfd->file, vma); | |
272 | if (ret != 0) | |
273 | return ret; | |
274 | sfd->vm_ops = vma->vm_ops; | |
275 | #ifdef CONFIG_MMU | |
276 | BUG_ON(!sfd->vm_ops->fault); | |
277 | #endif | |
278 | vma->vm_ops = &shm_vm_ops; | |
279 | shm_open(vma); | |
280 | ||
281 | return ret; | |
282 | } | |
283 | ||
284 | static int shm_release(struct inode *ino, struct file *file) | |
285 | { | |
286 | struct shm_file_data *sfd = shm_file_data(file); | |
287 | ||
288 | put_ipc_ns(sfd->ns); | |
289 | shm_file_data(file) = NULL; | |
290 | kfree(sfd); | |
291 | return 0; | |
292 | } | |
293 | ||
294 | static int shm_fsync(struct file *file, struct dentry *dentry, int datasync) | |
295 | { | |
296 | int (*fsync) (struct file *, struct dentry *, int datasync); | |
297 | struct shm_file_data *sfd = shm_file_data(file); | |
298 | int ret = -EINVAL; | |
299 | ||
300 | fsync = sfd->file->f_op->fsync; | |
301 | if (fsync) | |
302 | ret = fsync(sfd->file, sfd->file->f_path.dentry, datasync); | |
303 | return ret; | |
304 | } | |
305 | ||
306 | static unsigned long shm_get_unmapped_area(struct file *file, | |
307 | unsigned long addr, unsigned long len, unsigned long pgoff, | |
308 | unsigned long flags) | |
309 | { | |
310 | struct shm_file_data *sfd = shm_file_data(file); | |
311 | return get_unmapped_area(sfd->file, addr, len, pgoff, flags); | |
312 | } | |
313 | ||
314 | int is_file_shm_hugepages(struct file *file) | |
315 | { | |
316 | int ret = 0; | |
317 | ||
318 | if (file->f_op == &shm_file_operations) { | |
319 | struct shm_file_data *sfd; | |
320 | sfd = shm_file_data(file); | |
321 | ret = is_file_hugepages(sfd->file); | |
322 | } | |
323 | return ret; | |
324 | } | |
325 | ||
326 | static const struct file_operations shm_file_operations = { | |
327 | .mmap = shm_mmap, | |
328 | .fsync = shm_fsync, | |
329 | .release = shm_release, | |
330 | .get_unmapped_area = shm_get_unmapped_area, | |
331 | }; | |
332 | ||
333 | static struct vm_operations_struct shm_vm_ops = { | |
334 | .open = shm_open, /* callback for a new vm-area open */ | |
335 | .close = shm_close, /* callback for when the vm-area is released */ | |
336 | .fault = shm_fault, | |
337 | #if defined(CONFIG_NUMA) | |
338 | .set_policy = shm_set_policy, | |
339 | .get_policy = shm_get_policy, | |
340 | #endif | |
341 | }; | |
342 | ||
343 | static int newseg(struct ipc_namespace *ns, struct ipc_params *params) | |
344 | { | |
345 | key_t key = params->key; | |
346 | int shmflg = params->flg; | |
347 | size_t size = params->u.size; | |
348 | int error; | |
349 | struct shmid_kernel *shp; | |
350 | int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT; | |
351 | struct file * file; | |
352 | char name[13]; | |
353 | int id; | |
354 | ||
355 | if (size < SHMMIN || size > ns->shm_ctlmax) | |
356 | return -EINVAL; | |
357 | ||
358 | if (ns->shm_tot + numpages > ns->shm_ctlall) | |
359 | return -ENOSPC; | |
360 | ||
361 | shp = ipc_rcu_alloc(sizeof(*shp)); | |
362 | if (!shp) | |
363 | return -ENOMEM; | |
364 | ||
365 | shp->shm_perm.key = key; | |
366 | shp->shm_perm.mode = (shmflg & S_IRWXUGO); | |
367 | shp->mlock_user = NULL; | |
368 | ||
369 | shp->shm_perm.security = NULL; | |
370 | error = security_shm_alloc(shp); | |
371 | if (error) { | |
372 | ipc_rcu_putref(shp); | |
373 | return error; | |
374 | } | |
375 | ||
376 | sprintf (name, "SYSV%08x", key); | |
377 | if (shmflg & SHM_HUGETLB) { | |
378 | /* hugetlb_file_setup takes care of mlock user accounting */ | |
379 | file = hugetlb_file_setup(name, size); | |
380 | shp->mlock_user = current->user; | |
381 | } else { | |
382 | int acctflag = VM_ACCOUNT; | |
383 | /* | |
384 | * Do not allow no accounting for OVERCOMMIT_NEVER, even | |
385 | * if it's asked for. | |
386 | */ | |
387 | if ((shmflg & SHM_NORESERVE) && | |
388 | sysctl_overcommit_memory != OVERCOMMIT_NEVER) | |
389 | acctflag = 0; | |
390 | file = shmem_file_setup(name, size, acctflag); | |
391 | } | |
392 | error = PTR_ERR(file); | |
393 | if (IS_ERR(file)) | |
394 | goto no_file; | |
395 | ||
396 | error = -ENOSPC; | |
397 | id = shm_addid(ns, shp); | |
398 | if(id == -1) | |
399 | goto no_id; | |
400 | ||
401 | shp->shm_cprid = task_tgid_vnr(current); | |
402 | shp->shm_lprid = 0; | |
403 | shp->shm_atim = shp->shm_dtim = 0; | |
404 | shp->shm_ctim = get_seconds(); | |
405 | shp->shm_segsz = size; | |
406 | shp->shm_nattch = 0; | |
407 | shp->shm_perm.id = shm_buildid(ns, id, shp->shm_perm.seq); | |
408 | shp->shm_file = file; | |
409 | /* | |
410 | * shmid gets reported as "inode#" in /proc/pid/maps. | |
411 | * proc-ps tools use this. Changing this will break them. | |
412 | */ | |
413 | file->f_dentry->d_inode->i_ino = shp->shm_perm.id; | |
414 | ||
415 | ns->shm_tot += numpages; | |
416 | error = shp->shm_perm.id; | |
417 | shm_unlock(shp); | |
418 | return error; | |
419 | ||
420 | no_id: | |
421 | fput(file); | |
422 | no_file: | |
423 | security_shm_free(shp); | |
424 | ipc_rcu_putref(shp); | |
425 | return error; | |
426 | } | |
427 | ||
428 | static inline int shm_security(void *shp, int shmflg) | |
429 | { | |
430 | return security_shm_associate((struct shmid_kernel *) shp, shmflg); | |
431 | } | |
432 | ||
433 | static inline int shm_more_checks(void *shp, struct ipc_params *params) | |
434 | { | |
435 | if (((struct shmid_kernel *)shp)->shm_segsz < params->u.size) | |
436 | return -EINVAL; | |
437 | ||
438 | return 0; | |
439 | } | |
440 | ||
441 | asmlinkage long sys_shmget (key_t key, size_t size, int shmflg) | |
442 | { | |
443 | struct ipc_namespace *ns; | |
444 | struct ipc_ops shm_ops; | |
445 | struct ipc_params shm_params; | |
446 | ||
447 | ns = current->nsproxy->ipc_ns; | |
448 | ||
449 | shm_ops.getnew = newseg; | |
450 | shm_ops.associate = shm_security; | |
451 | shm_ops.more_checks = shm_more_checks; | |
452 | ||
453 | shm_params.key = key; | |
454 | shm_params.flg = shmflg; | |
455 | shm_params.u.size = size; | |
456 | ||
457 | return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params); | |
458 | } | |
459 | ||
460 | static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version) | |
461 | { | |
462 | switch(version) { | |
463 | case IPC_64: | |
464 | return copy_to_user(buf, in, sizeof(*in)); | |
465 | case IPC_OLD: | |
466 | { | |
467 | struct shmid_ds out; | |
468 | ||
469 | ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm); | |
470 | out.shm_segsz = in->shm_segsz; | |
471 | out.shm_atime = in->shm_atime; | |
472 | out.shm_dtime = in->shm_dtime; | |
473 | out.shm_ctime = in->shm_ctime; | |
474 | out.shm_cpid = in->shm_cpid; | |
475 | out.shm_lpid = in->shm_lpid; | |
476 | out.shm_nattch = in->shm_nattch; | |
477 | ||
478 | return copy_to_user(buf, &out, sizeof(out)); | |
479 | } | |
480 | default: | |
481 | return -EINVAL; | |
482 | } | |
483 | } | |
484 | ||
485 | struct shm_setbuf { | |
486 | uid_t uid; | |
487 | gid_t gid; | |
488 | mode_t mode; | |
489 | }; | |
490 | ||
491 | static inline unsigned long copy_shmid_from_user(struct shm_setbuf *out, void __user *buf, int version) | |
492 | { | |
493 | switch(version) { | |
494 | case IPC_64: | |
495 | { | |
496 | struct shmid64_ds tbuf; | |
497 | ||
498 | if (copy_from_user(&tbuf, buf, sizeof(tbuf))) | |
499 | return -EFAULT; | |
500 | ||
501 | out->uid = tbuf.shm_perm.uid; | |
502 | out->gid = tbuf.shm_perm.gid; | |
503 | out->mode = tbuf.shm_perm.mode; | |
504 | ||
505 | return 0; | |
506 | } | |
507 | case IPC_OLD: | |
508 | { | |
509 | struct shmid_ds tbuf_old; | |
510 | ||
511 | if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old))) | |
512 | return -EFAULT; | |
513 | ||
514 | out->uid = tbuf_old.shm_perm.uid; | |
515 | out->gid = tbuf_old.shm_perm.gid; | |
516 | out->mode = tbuf_old.shm_perm.mode; | |
517 | ||
518 | return 0; | |
519 | } | |
520 | default: | |
521 | return -EINVAL; | |
522 | } | |
523 | } | |
524 | ||
525 | static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version) | |
526 | { | |
527 | switch(version) { | |
528 | case IPC_64: | |
529 | return copy_to_user(buf, in, sizeof(*in)); | |
530 | case IPC_OLD: | |
531 | { | |
532 | struct shminfo out; | |
533 | ||
534 | if(in->shmmax > INT_MAX) | |
535 | out.shmmax = INT_MAX; | |
536 | else | |
537 | out.shmmax = (int)in->shmmax; | |
538 | ||
539 | out.shmmin = in->shmmin; | |
540 | out.shmmni = in->shmmni; | |
541 | out.shmseg = in->shmseg; | |
542 | out.shmall = in->shmall; | |
543 | ||
544 | return copy_to_user(buf, &out, sizeof(out)); | |
545 | } | |
546 | default: | |
547 | return -EINVAL; | |
548 | } | |
549 | } | |
550 | ||
551 | static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss, | |
552 | unsigned long *swp) | |
553 | { | |
554 | int next_id; | |
555 | int total, in_use; | |
556 | ||
557 | *rss = 0; | |
558 | *swp = 0; | |
559 | ||
560 | in_use = shm_ids(ns).in_use; | |
561 | ||
562 | for (total = 0, next_id = 0; total < in_use; next_id++) { | |
563 | struct shmid_kernel *shp; | |
564 | struct inode *inode; | |
565 | ||
566 | shp = shm_get(ns, next_id); | |
567 | if (shp == NULL) | |
568 | continue; | |
569 | ||
570 | inode = shp->shm_file->f_path.dentry->d_inode; | |
571 | ||
572 | if (is_file_hugepages(shp->shm_file)) { | |
573 | struct address_space *mapping = inode->i_mapping; | |
574 | *rss += (HPAGE_SIZE/PAGE_SIZE)*mapping->nrpages; | |
575 | } else { | |
576 | struct shmem_inode_info *info = SHMEM_I(inode); | |
577 | spin_lock(&info->lock); | |
578 | *rss += inode->i_mapping->nrpages; | |
579 | *swp += info->swapped; | |
580 | spin_unlock(&info->lock); | |
581 | } | |
582 | ||
583 | total++; | |
584 | } | |
585 | } | |
586 | ||
587 | asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf) | |
588 | { | |
589 | struct shm_setbuf setbuf; | |
590 | struct shmid_kernel *shp; | |
591 | int err, version; | |
592 | struct ipc_namespace *ns; | |
593 | ||
594 | if (cmd < 0 || shmid < 0) { | |
595 | err = -EINVAL; | |
596 | goto out; | |
597 | } | |
598 | ||
599 | version = ipc_parse_version(&cmd); | |
600 | ns = current->nsproxy->ipc_ns; | |
601 | ||
602 | switch (cmd) { /* replace with proc interface ? */ | |
603 | case IPC_INFO: | |
604 | { | |
605 | struct shminfo64 shminfo; | |
606 | ||
607 | err = security_shm_shmctl(NULL, cmd); | |
608 | if (err) | |
609 | return err; | |
610 | ||
611 | memset(&shminfo,0,sizeof(shminfo)); | |
612 | shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni; | |
613 | shminfo.shmmax = ns->shm_ctlmax; | |
614 | shminfo.shmall = ns->shm_ctlall; | |
615 | ||
616 | shminfo.shmmin = SHMMIN; | |
617 | if(copy_shminfo_to_user (buf, &shminfo, version)) | |
618 | return -EFAULT; | |
619 | /* reading a integer is always atomic */ | |
620 | err = ipc_get_maxid(&shm_ids(ns)); | |
621 | if(err<0) | |
622 | err = 0; | |
623 | goto out; | |
624 | } | |
625 | case SHM_INFO: | |
626 | { | |
627 | struct shm_info shm_info; | |
628 | ||
629 | err = security_shm_shmctl(NULL, cmd); | |
630 | if (err) | |
631 | return err; | |
632 | ||
633 | memset(&shm_info,0,sizeof(shm_info)); | |
634 | mutex_lock(&shm_ids(ns).mutex); | |
635 | shm_info.used_ids = shm_ids(ns).in_use; | |
636 | shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp); | |
637 | shm_info.shm_tot = ns->shm_tot; | |
638 | shm_info.swap_attempts = 0; | |
639 | shm_info.swap_successes = 0; | |
640 | err = ipc_get_maxid(&shm_ids(ns)); | |
641 | mutex_unlock(&shm_ids(ns).mutex); | |
642 | if(copy_to_user (buf, &shm_info, sizeof(shm_info))) { | |
643 | err = -EFAULT; | |
644 | goto out; | |
645 | } | |
646 | ||
647 | err = err < 0 ? 0 : err; | |
648 | goto out; | |
649 | } | |
650 | case SHM_STAT: | |
651 | case IPC_STAT: | |
652 | { | |
653 | struct shmid64_ds tbuf; | |
654 | int result; | |
655 | memset(&tbuf, 0, sizeof(tbuf)); | |
656 | shp = shm_lock(ns, shmid); | |
657 | if(shp==NULL) { | |
658 | err = -EINVAL; | |
659 | goto out; | |
660 | } else if (cmd == SHM_STAT) { | |
661 | result = shp->shm_perm.id; | |
662 | } else { | |
663 | err = shm_checkid(ns, shp,shmid); | |
664 | if(err) | |
665 | goto out_unlock; | |
666 | result = 0; | |
667 | } | |
668 | err=-EACCES; | |
669 | if (ipcperms (&shp->shm_perm, S_IRUGO)) | |
670 | goto out_unlock; | |
671 | err = security_shm_shmctl(shp, cmd); | |
672 | if (err) | |
673 | goto out_unlock; | |
674 | kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm); | |
675 | tbuf.shm_segsz = shp->shm_segsz; | |
676 | tbuf.shm_atime = shp->shm_atim; | |
677 | tbuf.shm_dtime = shp->shm_dtim; | |
678 | tbuf.shm_ctime = shp->shm_ctim; | |
679 | tbuf.shm_cpid = shp->shm_cprid; | |
680 | tbuf.shm_lpid = shp->shm_lprid; | |
681 | tbuf.shm_nattch = shp->shm_nattch; | |
682 | shm_unlock(shp); | |
683 | if(copy_shmid_to_user (buf, &tbuf, version)) | |
684 | err = -EFAULT; | |
685 | else | |
686 | err = result; | |
687 | goto out; | |
688 | } | |
689 | case SHM_LOCK: | |
690 | case SHM_UNLOCK: | |
691 | { | |
692 | shp = shm_lock(ns, shmid); | |
693 | if(shp==NULL) { | |
694 | err = -EINVAL; | |
695 | goto out; | |
696 | } | |
697 | err = shm_checkid(ns, shp,shmid); | |
698 | if(err) | |
699 | goto out_unlock; | |
700 | ||
701 | err = audit_ipc_obj(&(shp->shm_perm)); | |
702 | if (err) | |
703 | goto out_unlock; | |
704 | ||
705 | if (!capable(CAP_IPC_LOCK)) { | |
706 | err = -EPERM; | |
707 | if (current->euid != shp->shm_perm.uid && | |
708 | current->euid != shp->shm_perm.cuid) | |
709 | goto out_unlock; | |
710 | if (cmd == SHM_LOCK && | |
711 | !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur) | |
712 | goto out_unlock; | |
713 | } | |
714 | ||
715 | err = security_shm_shmctl(shp, cmd); | |
716 | if (err) | |
717 | goto out_unlock; | |
718 | ||
719 | if(cmd==SHM_LOCK) { | |
720 | struct user_struct * user = current->user; | |
721 | if (!is_file_hugepages(shp->shm_file)) { | |
722 | err = shmem_lock(shp->shm_file, 1, user); | |
723 | if (!err && !(shp->shm_perm.mode & SHM_LOCKED)){ | |
724 | shp->shm_perm.mode |= SHM_LOCKED; | |
725 | shp->mlock_user = user; | |
726 | } | |
727 | } | |
728 | } else if (!is_file_hugepages(shp->shm_file)) { | |
729 | shmem_lock(shp->shm_file, 0, shp->mlock_user); | |
730 | shp->shm_perm.mode &= ~SHM_LOCKED; | |
731 | shp->mlock_user = NULL; | |
732 | } | |
733 | shm_unlock(shp); | |
734 | goto out; | |
735 | } | |
736 | case IPC_RMID: | |
737 | { | |
738 | /* | |
739 | * We cannot simply remove the file. The SVID states | |
740 | * that the block remains until the last person | |
741 | * detaches from it, then is deleted. A shmat() on | |
742 | * an RMID segment is legal in older Linux and if | |
743 | * we change it apps break... | |
744 | * | |
745 | * Instead we set a destroyed flag, and then blow | |
746 | * the name away when the usage hits zero. | |
747 | */ | |
748 | mutex_lock(&shm_ids(ns).mutex); | |
749 | shp = shm_lock(ns, shmid); | |
750 | err = -EINVAL; | |
751 | if (shp == NULL) | |
752 | goto out_up; | |
753 | err = shm_checkid(ns, shp, shmid); | |
754 | if(err) | |
755 | goto out_unlock_up; | |
756 | ||
757 | err = audit_ipc_obj(&(shp->shm_perm)); | |
758 | if (err) | |
759 | goto out_unlock_up; | |
760 | ||
761 | if (current->euid != shp->shm_perm.uid && | |
762 | current->euid != shp->shm_perm.cuid && | |
763 | !capable(CAP_SYS_ADMIN)) { | |
764 | err=-EPERM; | |
765 | goto out_unlock_up; | |
766 | } | |
767 | ||
768 | err = security_shm_shmctl(shp, cmd); | |
769 | if (err) | |
770 | goto out_unlock_up; | |
771 | ||
772 | do_shm_rmid(ns, shp); | |
773 | mutex_unlock(&shm_ids(ns).mutex); | |
774 | goto out; | |
775 | } | |
776 | ||
777 | case IPC_SET: | |
778 | { | |
779 | if (copy_shmid_from_user (&setbuf, buf, version)) { | |
780 | err = -EFAULT; | |
781 | goto out; | |
782 | } | |
783 | mutex_lock(&shm_ids(ns).mutex); | |
784 | shp = shm_lock(ns, shmid); | |
785 | err=-EINVAL; | |
786 | if(shp==NULL) | |
787 | goto out_up; | |
788 | err = shm_checkid(ns, shp,shmid); | |
789 | if(err) | |
790 | goto out_unlock_up; | |
791 | err = audit_ipc_obj(&(shp->shm_perm)); | |
792 | if (err) | |
793 | goto out_unlock_up; | |
794 | err = audit_ipc_set_perm(0, setbuf.uid, setbuf.gid, setbuf.mode); | |
795 | if (err) | |
796 | goto out_unlock_up; | |
797 | err=-EPERM; | |
798 | if (current->euid != shp->shm_perm.uid && | |
799 | current->euid != shp->shm_perm.cuid && | |
800 | !capable(CAP_SYS_ADMIN)) { | |
801 | goto out_unlock_up; | |
802 | } | |
803 | ||
804 | err = security_shm_shmctl(shp, cmd); | |
805 | if (err) | |
806 | goto out_unlock_up; | |
807 | ||
808 | shp->shm_perm.uid = setbuf.uid; | |
809 | shp->shm_perm.gid = setbuf.gid; | |
810 | shp->shm_perm.mode = (shp->shm_perm.mode & ~S_IRWXUGO) | |
811 | | (setbuf.mode & S_IRWXUGO); | |
812 | shp->shm_ctim = get_seconds(); | |
813 | break; | |
814 | } | |
815 | ||
816 | default: | |
817 | err = -EINVAL; | |
818 | goto out; | |
819 | } | |
820 | ||
821 | err = 0; | |
822 | out_unlock_up: | |
823 | shm_unlock(shp); | |
824 | out_up: | |
825 | mutex_unlock(&shm_ids(ns).mutex); | |
826 | goto out; | |
827 | out_unlock: | |
828 | shm_unlock(shp); | |
829 | out: | |
830 | return err; | |
831 | } | |
832 | ||
833 | /* | |
834 | * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists. | |
835 | * | |
836 | * NOTE! Despite the name, this is NOT a direct system call entrypoint. The | |
837 | * "raddr" thing points to kernel space, and there has to be a wrapper around | |
838 | * this. | |
839 | */ | |
840 | long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr) | |
841 | { | |
842 | struct shmid_kernel *shp; | |
843 | unsigned long addr; | |
844 | unsigned long size; | |
845 | struct file * file; | |
846 | int err; | |
847 | unsigned long flags; | |
848 | unsigned long prot; | |
849 | int acc_mode; | |
850 | unsigned long user_addr; | |
851 | struct ipc_namespace *ns; | |
852 | struct shm_file_data *sfd; | |
853 | struct path path; | |
854 | mode_t f_mode; | |
855 | ||
856 | err = -EINVAL; | |
857 | if (shmid < 0) | |
858 | goto out; | |
859 | else if ((addr = (ulong)shmaddr)) { | |
860 | if (addr & (SHMLBA-1)) { | |
861 | if (shmflg & SHM_RND) | |
862 | addr &= ~(SHMLBA-1); /* round down */ | |
863 | else | |
864 | #ifndef __ARCH_FORCE_SHMLBA | |
865 | if (addr & ~PAGE_MASK) | |
866 | #endif | |
867 | goto out; | |
868 | } | |
869 | flags = MAP_SHARED | MAP_FIXED; | |
870 | } else { | |
871 | if ((shmflg & SHM_REMAP)) | |
872 | goto out; | |
873 | ||
874 | flags = MAP_SHARED; | |
875 | } | |
876 | ||
877 | if (shmflg & SHM_RDONLY) { | |
878 | prot = PROT_READ; | |
879 | acc_mode = S_IRUGO; | |
880 | f_mode = FMODE_READ; | |
881 | } else { | |
882 | prot = PROT_READ | PROT_WRITE; | |
883 | acc_mode = S_IRUGO | S_IWUGO; | |
884 | f_mode = FMODE_READ | FMODE_WRITE; | |
885 | } | |
886 | if (shmflg & SHM_EXEC) { | |
887 | prot |= PROT_EXEC; | |
888 | acc_mode |= S_IXUGO; | |
889 | } | |
890 | ||
891 | /* | |
892 | * We cannot rely on the fs check since SYSV IPC does have an | |
893 | * additional creator id... | |
894 | */ | |
895 | ns = current->nsproxy->ipc_ns; | |
896 | shp = shm_lock(ns, shmid); | |
897 | if(shp == NULL) | |
898 | goto out; | |
899 | ||
900 | err = shm_checkid(ns, shp,shmid); | |
901 | if (err) | |
902 | goto out_unlock; | |
903 | ||
904 | err = -EACCES; | |
905 | if (ipcperms(&shp->shm_perm, acc_mode)) | |
906 | goto out_unlock; | |
907 | ||
908 | err = security_shm_shmat(shp, shmaddr, shmflg); | |
909 | if (err) | |
910 | goto out_unlock; | |
911 | ||
912 | path.dentry = dget(shp->shm_file->f_path.dentry); | |
913 | path.mnt = shp->shm_file->f_path.mnt; | |
914 | shp->shm_nattch++; | |
915 | size = i_size_read(path.dentry->d_inode); | |
916 | shm_unlock(shp); | |
917 | ||
918 | err = -ENOMEM; | |
919 | sfd = kzalloc(sizeof(*sfd), GFP_KERNEL); | |
920 | if (!sfd) | |
921 | goto out_put_dentry; | |
922 | ||
923 | err = -ENOMEM; | |
924 | ||
925 | file = alloc_file(path.mnt, path.dentry, f_mode, &shm_file_operations); | |
926 | if (!file) | |
927 | goto out_free; | |
928 | ||
929 | file->private_data = sfd; | |
930 | file->f_mapping = shp->shm_file->f_mapping; | |
931 | sfd->id = shp->shm_perm.id; | |
932 | sfd->ns = get_ipc_ns(ns); | |
933 | sfd->file = shp->shm_file; | |
934 | sfd->vm_ops = NULL; | |
935 | ||
936 | down_write(¤t->mm->mmap_sem); | |
937 | if (addr && !(shmflg & SHM_REMAP)) { | |
938 | err = -EINVAL; | |
939 | if (find_vma_intersection(current->mm, addr, addr + size)) | |
940 | goto invalid; | |
941 | /* | |
942 | * If shm segment goes below stack, make sure there is some | |
943 | * space left for the stack to grow (at least 4 pages). | |
944 | */ | |
945 | if (addr < current->mm->start_stack && | |
946 | addr > current->mm->start_stack - size - PAGE_SIZE * 5) | |
947 | goto invalid; | |
948 | } | |
949 | ||
950 | user_addr = do_mmap (file, addr, size, prot, flags, 0); | |
951 | *raddr = user_addr; | |
952 | err = 0; | |
953 | if (IS_ERR_VALUE(user_addr)) | |
954 | err = (long)user_addr; | |
955 | invalid: | |
956 | up_write(¤t->mm->mmap_sem); | |
957 | ||
958 | fput(file); | |
959 | ||
960 | out_nattch: | |
961 | mutex_lock(&shm_ids(ns).mutex); | |
962 | shp = shm_lock(ns, shmid); | |
963 | BUG_ON(!shp); | |
964 | shp->shm_nattch--; | |
965 | if(shp->shm_nattch == 0 && | |
966 | shp->shm_perm.mode & SHM_DEST) | |
967 | shm_destroy(ns, shp); | |
968 | else | |
969 | shm_unlock(shp); | |
970 | mutex_unlock(&shm_ids(ns).mutex); | |
971 | ||
972 | out: | |
973 | return err; | |
974 | ||
975 | out_unlock: | |
976 | shm_unlock(shp); | |
977 | goto out; | |
978 | ||
979 | out_free: | |
980 | kfree(sfd); | |
981 | out_put_dentry: | |
982 | dput(path.dentry); | |
983 | goto out_nattch; | |
984 | } | |
985 | ||
986 | asmlinkage long sys_shmat(int shmid, char __user *shmaddr, int shmflg) | |
987 | { | |
988 | unsigned long ret; | |
989 | long err; | |
990 | ||
991 | err = do_shmat(shmid, shmaddr, shmflg, &ret); | |
992 | if (err) | |
993 | return err; | |
994 | force_successful_syscall_return(); | |
995 | return (long)ret; | |
996 | } | |
997 | ||
998 | /* | |
999 | * detach and kill segment if marked destroyed. | |
1000 | * The work is done in shm_close. | |
1001 | */ | |
1002 | asmlinkage long sys_shmdt(char __user *shmaddr) | |
1003 | { | |
1004 | struct mm_struct *mm = current->mm; | |
1005 | struct vm_area_struct *vma, *next; | |
1006 | unsigned long addr = (unsigned long)shmaddr; | |
1007 | loff_t size = 0; | |
1008 | int retval = -EINVAL; | |
1009 | ||
1010 | if (addr & ~PAGE_MASK) | |
1011 | return retval; | |
1012 | ||
1013 | down_write(&mm->mmap_sem); | |
1014 | ||
1015 | /* | |
1016 | * This function tries to be smart and unmap shm segments that | |
1017 | * were modified by partial mlock or munmap calls: | |
1018 | * - It first determines the size of the shm segment that should be | |
1019 | * unmapped: It searches for a vma that is backed by shm and that | |
1020 | * started at address shmaddr. It records it's size and then unmaps | |
1021 | * it. | |
1022 | * - Then it unmaps all shm vmas that started at shmaddr and that | |
1023 | * are within the initially determined size. | |
1024 | * Errors from do_munmap are ignored: the function only fails if | |
1025 | * it's called with invalid parameters or if it's called to unmap | |
1026 | * a part of a vma. Both calls in this function are for full vmas, | |
1027 | * the parameters are directly copied from the vma itself and always | |
1028 | * valid - therefore do_munmap cannot fail. (famous last words?) | |
1029 | */ | |
1030 | /* | |
1031 | * If it had been mremap()'d, the starting address would not | |
1032 | * match the usual checks anyway. So assume all vma's are | |
1033 | * above the starting address given. | |
1034 | */ | |
1035 | vma = find_vma(mm, addr); | |
1036 | ||
1037 | while (vma) { | |
1038 | next = vma->vm_next; | |
1039 | ||
1040 | /* | |
1041 | * Check if the starting address would match, i.e. it's | |
1042 | * a fragment created by mprotect() and/or munmap(), or it | |
1043 | * otherwise it starts at this address with no hassles. | |
1044 | */ | |
1045 | if ((vma->vm_ops == &shm_vm_ops) && | |
1046 | (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) { | |
1047 | ||
1048 | ||
1049 | size = vma->vm_file->f_path.dentry->d_inode->i_size; | |
1050 | do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start); | |
1051 | /* | |
1052 | * We discovered the size of the shm segment, so | |
1053 | * break out of here and fall through to the next | |
1054 | * loop that uses the size information to stop | |
1055 | * searching for matching vma's. | |
1056 | */ | |
1057 | retval = 0; | |
1058 | vma = next; | |
1059 | break; | |
1060 | } | |
1061 | vma = next; | |
1062 | } | |
1063 | ||
1064 | /* | |
1065 | * We need look no further than the maximum address a fragment | |
1066 | * could possibly have landed at. Also cast things to loff_t to | |
1067 | * prevent overflows and make comparisions vs. equal-width types. | |
1068 | */ | |
1069 | size = PAGE_ALIGN(size); | |
1070 | while (vma && (loff_t)(vma->vm_end - addr) <= size) { | |
1071 | next = vma->vm_next; | |
1072 | ||
1073 | /* finding a matching vma now does not alter retval */ | |
1074 | if ((vma->vm_ops == &shm_vm_ops) && | |
1075 | (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) | |
1076 | ||
1077 | do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start); | |
1078 | vma = next; | |
1079 | } | |
1080 | ||
1081 | up_write(&mm->mmap_sem); | |
1082 | return retval; | |
1083 | } | |
1084 | ||
1085 | #ifdef CONFIG_PROC_FS | |
1086 | static int sysvipc_shm_proc_show(struct seq_file *s, void *it) | |
1087 | { | |
1088 | struct shmid_kernel *shp = it; | |
1089 | char *format; | |
1090 | ||
1091 | #define SMALL_STRING "%10d %10d %4o %10u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n" | |
1092 | #define BIG_STRING "%10d %10d %4o %21u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n" | |
1093 | ||
1094 | if (sizeof(size_t) <= sizeof(int)) | |
1095 | format = SMALL_STRING; | |
1096 | else | |
1097 | format = BIG_STRING; | |
1098 | return seq_printf(s, format, | |
1099 | shp->shm_perm.key, | |
1100 | shp->shm_perm.id, | |
1101 | shp->shm_perm.mode, | |
1102 | shp->shm_segsz, | |
1103 | shp->shm_cprid, | |
1104 | shp->shm_lprid, | |
1105 | shp->shm_nattch, | |
1106 | shp->shm_perm.uid, | |
1107 | shp->shm_perm.gid, | |
1108 | shp->shm_perm.cuid, | |
1109 | shp->shm_perm.cgid, | |
1110 | shp->shm_atim, | |
1111 | shp->shm_dtim, | |
1112 | shp->shm_ctim); | |
1113 | } | |
1114 | #endif |