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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/rwsem.h> |
39 | #include <linux/nsproxy.h> |
40 | #include <linux/mount.h> |
41 | #include <linux/ipc_namespace.h> |
42 | |
43 | #include <asm/uaccess.h> |
44 | |
45 | #include "util.h" |
46 | |
47 | struct shm_file_data { |
48 | int id; |
49 | struct ipc_namespace *ns; |
50 | struct file *file; |
51 | const struct vm_operations_struct *vm_ops; |
52 | }; |
53 | |
54 | #define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data)) |
55 | |
56 | static const struct file_operations shm_file_operations; |
57 | static const struct vm_operations_struct shm_vm_ops; |
58 | |
59 | #define shm_ids(ns) ((ns)->ids[IPC_SHM_IDS]) |
60 | |
61 | #define shm_unlock(shp) \ |
62 | ipc_unlock(&(shp)->shm_perm) |
63 | |
64 | static int newseg(struct ipc_namespace *, struct ipc_params *); |
65 | static void shm_open(struct vm_area_struct *vma); |
66 | static void shm_close(struct vm_area_struct *vma); |
67 | static void shm_destroy (struct ipc_namespace *ns, struct shmid_kernel *shp); |
68 | #ifdef CONFIG_PROC_FS |
69 | static int sysvipc_shm_proc_show(struct seq_file *s, void *it); |
70 | #endif |
71 | |
72 | void shm_init_ns(struct ipc_namespace *ns) |
73 | { |
74 | ns->shm_ctlmax = SHMMAX; |
75 | ns->shm_ctlall = SHMALL; |
76 | ns->shm_ctlmni = SHMMNI; |
77 | ns->shm_tot = 0; |
78 | ipc_init_ids(&shm_ids(ns)); |
79 | } |
80 | |
81 | /* |
82 | * Called with shm_ids.rw_mutex (writer) and the shp structure locked. |
83 | * Only shm_ids.rw_mutex remains locked on exit. |
84 | */ |
85 | static void do_shm_rmid(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp) |
86 | { |
87 | struct shmid_kernel *shp; |
88 | shp = container_of(ipcp, struct shmid_kernel, shm_perm); |
89 | |
90 | if (shp->shm_nattch){ |
91 | shp->shm_perm.mode |= SHM_DEST; |
92 | /* Do not find it any more */ |
93 | shp->shm_perm.key = IPC_PRIVATE; |
94 | shm_unlock(shp); |
95 | } else |
96 | shm_destroy(ns, shp); |
97 | } |
98 | |
99 | #ifdef CONFIG_IPC_NS |
100 | void shm_exit_ns(struct ipc_namespace *ns) |
101 | { |
102 | free_ipcs(ns, &shm_ids(ns), do_shm_rmid); |
103 | idr_destroy(&ns->ids[IPC_SHM_IDS].ipcs_idr); |
104 | } |
105 | #endif |
106 | |
107 | void __init shm_init (void) |
108 | { |
109 | shm_init_ns(&init_ipc_ns); |
110 | ipc_init_proc_interface("sysvipc/shm", |
111 | #if BITS_PER_LONG <= 32 |
112 | " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n", |
113 | #else |
114 | " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime rss swap\n", |
115 | #endif |
116 | IPC_SHM_IDS, sysvipc_shm_proc_show); |
117 | } |
118 | |
119 | /* |
120 | * shm_lock_(check_) routines are called in the paths where the rw_mutex |
121 | * is not necessarily held. |
122 | */ |
123 | static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id) |
124 | { |
125 | struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id); |
126 | |
127 | if (IS_ERR(ipcp)) |
128 | return (struct shmid_kernel *)ipcp; |
129 | |
130 | return container_of(ipcp, struct shmid_kernel, shm_perm); |
131 | } |
132 | |
133 | static inline struct shmid_kernel *shm_lock_check(struct ipc_namespace *ns, |
134 | int id) |
135 | { |
136 | struct kern_ipc_perm *ipcp = ipc_lock_check(&shm_ids(ns), id); |
137 | |
138 | if (IS_ERR(ipcp)) |
139 | return (struct shmid_kernel *)ipcp; |
140 | |
141 | return container_of(ipcp, struct shmid_kernel, shm_perm); |
142 | } |
143 | |
144 | static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s) |
145 | { |
146 | ipc_rmid(&shm_ids(ns), &s->shm_perm); |
147 | } |
148 | |
149 | |
150 | /* This is called by fork, once for every shm attach. */ |
151 | static void shm_open(struct vm_area_struct *vma) |
152 | { |
153 | struct file *file = vma->vm_file; |
154 | struct shm_file_data *sfd = shm_file_data(file); |
155 | struct shmid_kernel *shp; |
156 | |
157 | shp = shm_lock(sfd->ns, sfd->id); |
158 | BUG_ON(IS_ERR(shp)); |
159 | shp->shm_atim = get_seconds(); |
160 | shp->shm_lprid = task_tgid_vnr(current); |
161 | shp->shm_nattch++; |
162 | shm_unlock(shp); |
163 | } |
164 | |
165 | /* |
166 | * shm_destroy - free the struct shmid_kernel |
167 | * |
168 | * @ns: namespace |
169 | * @shp: struct to free |
170 | * |
171 | * It has to be called with shp and shm_ids.rw_mutex (writer) locked, |
172 | * but returns with shp unlocked and freed. |
173 | */ |
174 | static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp) |
175 | { |
176 | ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT; |
177 | shm_rmid(ns, shp); |
178 | shm_unlock(shp); |
179 | if (!is_file_hugepages(shp->shm_file)) |
180 | shmem_lock(shp->shm_file, 0, shp->mlock_user); |
181 | else if (shp->mlock_user) |
182 | user_shm_unlock(shp->shm_file->f_path.dentry->d_inode->i_size, |
183 | shp->mlock_user); |
184 | fput (shp->shm_file); |
185 | security_shm_free(shp); |
186 | ipc_rcu_putref(shp); |
187 | } |
188 | |
189 | /* |
190 | * remove the attach descriptor vma. |
191 | * free memory for segment if it is marked destroyed. |
192 | * The descriptor has already been removed from the current->mm->mmap list |
193 | * and will later be kfree()d. |
194 | */ |
195 | static void shm_close(struct vm_area_struct *vma) |
196 | { |
197 | struct file * file = vma->vm_file; |
198 | struct shm_file_data *sfd = shm_file_data(file); |
199 | struct shmid_kernel *shp; |
200 | struct ipc_namespace *ns = sfd->ns; |
201 | |
202 | down_write(&shm_ids(ns).rw_mutex); |
203 | /* remove from the list of attaches of the shm segment */ |
204 | shp = shm_lock(ns, sfd->id); |
205 | BUG_ON(IS_ERR(shp)); |
206 | shp->shm_lprid = task_tgid_vnr(current); |
207 | shp->shm_dtim = get_seconds(); |
208 | shp->shm_nattch--; |
209 | if(shp->shm_nattch == 0 && |
210 | shp->shm_perm.mode & SHM_DEST) |
211 | shm_destroy(ns, shp); |
212 | else |
213 | shm_unlock(shp); |
214 | up_write(&shm_ids(ns).rw_mutex); |
215 | } |
216 | |
217 | static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
218 | { |
219 | struct file *file = vma->vm_file; |
220 | struct shm_file_data *sfd = shm_file_data(file); |
221 | |
222 | return sfd->vm_ops->fault(vma, vmf); |
223 | } |
224 | |
225 | #ifdef CONFIG_NUMA |
226 | static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new) |
227 | { |
228 | struct file *file = vma->vm_file; |
229 | struct shm_file_data *sfd = shm_file_data(file); |
230 | int err = 0; |
231 | if (sfd->vm_ops->set_policy) |
232 | err = sfd->vm_ops->set_policy(vma, new); |
233 | return err; |
234 | } |
235 | |
236 | static struct mempolicy *shm_get_policy(struct vm_area_struct *vma, |
237 | unsigned long addr) |
238 | { |
239 | struct file *file = vma->vm_file; |
240 | struct shm_file_data *sfd = shm_file_data(file); |
241 | struct mempolicy *pol = NULL; |
242 | |
243 | if (sfd->vm_ops->get_policy) |
244 | pol = sfd->vm_ops->get_policy(vma, addr); |
245 | else if (vma->vm_policy) |
246 | pol = vma->vm_policy; |
247 | |
248 | return pol; |
249 | } |
250 | #endif |
251 | |
252 | static int shm_mmap(struct file * file, struct vm_area_struct * vma) |
253 | { |
254 | struct shm_file_data *sfd = shm_file_data(file); |
255 | int ret; |
256 | |
257 | ret = sfd->file->f_op->mmap(sfd->file, vma); |
258 | if (ret != 0) |
259 | return ret; |
260 | sfd->vm_ops = vma->vm_ops; |
261 | #ifdef CONFIG_MMU |
262 | BUG_ON(!sfd->vm_ops->fault); |
263 | #endif |
264 | vma->vm_ops = &shm_vm_ops; |
265 | shm_open(vma); |
266 | |
267 | return ret; |
268 | } |
269 | |
270 | static int shm_release(struct inode *ino, struct file *file) |
271 | { |
272 | struct shm_file_data *sfd = shm_file_data(file); |
273 | |
274 | put_ipc_ns(sfd->ns); |
275 | shm_file_data(file) = NULL; |
276 | kfree(sfd); |
277 | return 0; |
278 | } |
279 | |
280 | static int shm_fsync(struct file *file, int datasync) |
281 | { |
282 | struct shm_file_data *sfd = shm_file_data(file); |
283 | |
284 | if (!sfd->file->f_op->fsync) |
285 | return -EINVAL; |
286 | return sfd->file->f_op->fsync(sfd->file, datasync); |
287 | } |
288 | |
289 | static unsigned long shm_get_unmapped_area(struct file *file, |
290 | unsigned long addr, unsigned long len, unsigned long pgoff, |
291 | unsigned long flags) |
292 | { |
293 | struct shm_file_data *sfd = shm_file_data(file); |
294 | return sfd->file->f_op->get_unmapped_area(sfd->file, addr, len, |
295 | pgoff, flags); |
296 | } |
297 | |
298 | static const struct file_operations shm_file_operations = { |
299 | .mmap = shm_mmap, |
300 | .fsync = shm_fsync, |
301 | .release = shm_release, |
302 | #ifndef CONFIG_MMU |
303 | .get_unmapped_area = shm_get_unmapped_area, |
304 | #endif |
305 | .llseek = noop_llseek, |
306 | }; |
307 | |
308 | static const struct file_operations shm_file_operations_huge = { |
309 | .mmap = shm_mmap, |
310 | .fsync = shm_fsync, |
311 | .release = shm_release, |
312 | .get_unmapped_area = shm_get_unmapped_area, |
313 | .llseek = noop_llseek, |
314 | }; |
315 | |
316 | int is_file_shm_hugepages(struct file *file) |
317 | { |
318 | return file->f_op == &shm_file_operations_huge; |
319 | } |
320 | |
321 | static const struct vm_operations_struct shm_vm_ops = { |
322 | .open = shm_open, /* callback for a new vm-area open */ |
323 | .close = shm_close, /* callback for when the vm-area is released */ |
324 | .fault = shm_fault, |
325 | #if defined(CONFIG_NUMA) |
326 | .set_policy = shm_set_policy, |
327 | .get_policy = shm_get_policy, |
328 | #endif |
329 | }; |
330 | |
331 | /** |
332 | * newseg - Create a new shared memory segment |
333 | * @ns: namespace |
334 | * @params: ptr to the structure that contains key, size and shmflg |
335 | * |
336 | * Called with shm_ids.rw_mutex held as a writer. |
337 | */ |
338 | |
339 | static int newseg(struct ipc_namespace *ns, struct ipc_params *params) |
340 | { |
341 | key_t key = params->key; |
342 | int shmflg = params->flg; |
343 | size_t size = params->u.size; |
344 | int error; |
345 | struct shmid_kernel *shp; |
346 | int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT; |
347 | struct file * file; |
348 | char name[13]; |
349 | int id; |
350 | int acctflag = 0; |
351 | |
352 | if (size < SHMMIN || size > ns->shm_ctlmax) |
353 | return -EINVAL; |
354 | |
355 | if (ns->shm_tot + numpages > ns->shm_ctlall) |
356 | return -ENOSPC; |
357 | |
358 | shp = ipc_rcu_alloc(sizeof(*shp)); |
359 | if (!shp) |
360 | return -ENOMEM; |
361 | |
362 | shp->shm_perm.key = key; |
363 | shp->shm_perm.mode = (shmflg & S_IRWXUGO); |
364 | shp->mlock_user = NULL; |
365 | |
366 | shp->shm_perm.security = NULL; |
367 | error = security_shm_alloc(shp); |
368 | if (error) { |
369 | ipc_rcu_putref(shp); |
370 | return error; |
371 | } |
372 | |
373 | sprintf (name, "SYSV%08x", key); |
374 | if (shmflg & SHM_HUGETLB) { |
375 | /* hugetlb_file_setup applies strict accounting */ |
376 | if (shmflg & SHM_NORESERVE) |
377 | acctflag = VM_NORESERVE; |
378 | file = hugetlb_file_setup(name, size, acctflag, |
379 | &shp->mlock_user, HUGETLB_SHMFS_INODE); |
380 | } else { |
381 | /* |
382 | * Do not allow no accounting for OVERCOMMIT_NEVER, even |
383 | * if it's asked for. |
384 | */ |
385 | if ((shmflg & SHM_NORESERVE) && |
386 | sysctl_overcommit_memory != OVERCOMMIT_NEVER) |
387 | acctflag = VM_NORESERVE; |
388 | file = shmem_file_setup(name, size, acctflag); |
389 | } |
390 | error = PTR_ERR(file); |
391 | if (IS_ERR(file)) |
392 | goto no_file; |
393 | |
394 | id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni); |
395 | if (id < 0) { |
396 | error = id; |
397 | goto no_id; |
398 | } |
399 | |
400 | shp->shm_cprid = task_tgid_vnr(current); |
401 | shp->shm_lprid = 0; |
402 | shp->shm_atim = shp->shm_dtim = 0; |
403 | shp->shm_ctim = get_seconds(); |
404 | shp->shm_segsz = size; |
405 | shp->shm_nattch = 0; |
406 | shp->shm_file = file; |
407 | /* |
408 | * shmid gets reported as "inode#" in /proc/pid/maps. |
409 | * proc-ps tools use this. Changing this will break them. |
410 | */ |
411 | file->f_dentry->d_inode->i_ino = shp->shm_perm.id; |
412 | |
413 | ns->shm_tot += numpages; |
414 | error = shp->shm_perm.id; |
415 | shm_unlock(shp); |
416 | return error; |
417 | |
418 | no_id: |
419 | if (is_file_hugepages(file) && shp->mlock_user) |
420 | user_shm_unlock(size, shp->mlock_user); |
421 | fput(file); |
422 | no_file: |
423 | security_shm_free(shp); |
424 | ipc_rcu_putref(shp); |
425 | return error; |
426 | } |
427 | |
428 | /* |
429 | * Called with shm_ids.rw_mutex and ipcp locked. |
430 | */ |
431 | static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg) |
432 | { |
433 | struct shmid_kernel *shp; |
434 | |
435 | shp = container_of(ipcp, struct shmid_kernel, shm_perm); |
436 | return security_shm_associate(shp, shmflg); |
437 | } |
438 | |
439 | /* |
440 | * Called with shm_ids.rw_mutex and ipcp locked. |
441 | */ |
442 | static inline int shm_more_checks(struct kern_ipc_perm *ipcp, |
443 | struct ipc_params *params) |
444 | { |
445 | struct shmid_kernel *shp; |
446 | |
447 | shp = container_of(ipcp, struct shmid_kernel, shm_perm); |
448 | if (shp->shm_segsz < params->u.size) |
449 | return -EINVAL; |
450 | |
451 | return 0; |
452 | } |
453 | |
454 | SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg) |
455 | { |
456 | struct ipc_namespace *ns; |
457 | struct ipc_ops shm_ops; |
458 | struct ipc_params shm_params; |
459 | |
460 | ns = current->nsproxy->ipc_ns; |
461 | |
462 | shm_ops.getnew = newseg; |
463 | shm_ops.associate = shm_security; |
464 | shm_ops.more_checks = shm_more_checks; |
465 | |
466 | shm_params.key = key; |
467 | shm_params.flg = shmflg; |
468 | shm_params.u.size = size; |
469 | |
470 | return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params); |
471 | } |
472 | |
473 | static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version) |
474 | { |
475 | switch(version) { |
476 | case IPC_64: |
477 | return copy_to_user(buf, in, sizeof(*in)); |
478 | case IPC_OLD: |
479 | { |
480 | struct shmid_ds out; |
481 | |
482 | memset(&out, 0, sizeof(out)); |
483 | ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm); |
484 | out.shm_segsz = in->shm_segsz; |
485 | out.shm_atime = in->shm_atime; |
486 | out.shm_dtime = in->shm_dtime; |
487 | out.shm_ctime = in->shm_ctime; |
488 | out.shm_cpid = in->shm_cpid; |
489 | out.shm_lpid = in->shm_lpid; |
490 | out.shm_nattch = in->shm_nattch; |
491 | |
492 | return copy_to_user(buf, &out, sizeof(out)); |
493 | } |
494 | default: |
495 | return -EINVAL; |
496 | } |
497 | } |
498 | |
499 | static inline unsigned long |
500 | copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version) |
501 | { |
502 | switch(version) { |
503 | case IPC_64: |
504 | if (copy_from_user(out, buf, sizeof(*out))) |
505 | return -EFAULT; |
506 | return 0; |
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->shm_perm.uid = tbuf_old.shm_perm.uid; |
515 | out->shm_perm.gid = tbuf_old.shm_perm.gid; |
516 | out->shm_perm.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 | /* |
552 | * Calculate and add used RSS and swap pages of a shm. |
553 | * Called with shm_ids.rw_mutex held as a reader |
554 | */ |
555 | static void shm_add_rss_swap(struct shmid_kernel *shp, |
556 | unsigned long *rss_add, unsigned long *swp_add) |
557 | { |
558 | struct inode *inode; |
559 | |
560 | inode = shp->shm_file->f_path.dentry->d_inode; |
561 | |
562 | if (is_file_hugepages(shp->shm_file)) { |
563 | struct address_space *mapping = inode->i_mapping; |
564 | struct hstate *h = hstate_file(shp->shm_file); |
565 | *rss_add += pages_per_huge_page(h) * mapping->nrpages; |
566 | } else { |
567 | #ifdef CONFIG_SHMEM |
568 | struct shmem_inode_info *info = SHMEM_I(inode); |
569 | spin_lock(&info->lock); |
570 | *rss_add += inode->i_mapping->nrpages; |
571 | *swp_add += info->swapped; |
572 | spin_unlock(&info->lock); |
573 | #else |
574 | *rss_add += inode->i_mapping->nrpages; |
575 | #endif |
576 | } |
577 | } |
578 | |
579 | /* |
580 | * Called with shm_ids.rw_mutex held as a reader |
581 | */ |
582 | static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss, |
583 | unsigned long *swp) |
584 | { |
585 | int next_id; |
586 | int total, in_use; |
587 | |
588 | *rss = 0; |
589 | *swp = 0; |
590 | |
591 | in_use = shm_ids(ns).in_use; |
592 | |
593 | for (total = 0, next_id = 0; total < in_use; next_id++) { |
594 | struct kern_ipc_perm *ipc; |
595 | struct shmid_kernel *shp; |
596 | |
597 | ipc = idr_find(&shm_ids(ns).ipcs_idr, next_id); |
598 | if (ipc == NULL) |
599 | continue; |
600 | shp = container_of(ipc, struct shmid_kernel, shm_perm); |
601 | |
602 | shm_add_rss_swap(shp, rss, swp); |
603 | |
604 | total++; |
605 | } |
606 | } |
607 | |
608 | /* |
609 | * This function handles some shmctl commands which require the rw_mutex |
610 | * to be held in write mode. |
611 | * NOTE: no locks must be held, the rw_mutex is taken inside this function. |
612 | */ |
613 | static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd, |
614 | struct shmid_ds __user *buf, int version) |
615 | { |
616 | struct kern_ipc_perm *ipcp; |
617 | struct shmid64_ds shmid64; |
618 | struct shmid_kernel *shp; |
619 | int err; |
620 | |
621 | if (cmd == IPC_SET) { |
622 | if (copy_shmid_from_user(&shmid64, buf, version)) |
623 | return -EFAULT; |
624 | } |
625 | |
626 | ipcp = ipcctl_pre_down(&shm_ids(ns), shmid, cmd, &shmid64.shm_perm, 0); |
627 | if (IS_ERR(ipcp)) |
628 | return PTR_ERR(ipcp); |
629 | |
630 | shp = container_of(ipcp, struct shmid_kernel, shm_perm); |
631 | |
632 | err = security_shm_shmctl(shp, cmd); |
633 | if (err) |
634 | goto out_unlock; |
635 | switch (cmd) { |
636 | case IPC_RMID: |
637 | do_shm_rmid(ns, ipcp); |
638 | goto out_up; |
639 | case IPC_SET: |
640 | ipc_update_perm(&shmid64.shm_perm, ipcp); |
641 | shp->shm_ctim = get_seconds(); |
642 | break; |
643 | default: |
644 | err = -EINVAL; |
645 | } |
646 | out_unlock: |
647 | shm_unlock(shp); |
648 | out_up: |
649 | up_write(&shm_ids(ns).rw_mutex); |
650 | return err; |
651 | } |
652 | |
653 | SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf) |
654 | { |
655 | struct shmid_kernel *shp; |
656 | int err, version; |
657 | struct ipc_namespace *ns; |
658 | |
659 | if (cmd < 0 || shmid < 0) { |
660 | err = -EINVAL; |
661 | goto out; |
662 | } |
663 | |
664 | version = ipc_parse_version(&cmd); |
665 | ns = current->nsproxy->ipc_ns; |
666 | |
667 | switch (cmd) { /* replace with proc interface ? */ |
668 | case IPC_INFO: |
669 | { |
670 | struct shminfo64 shminfo; |
671 | |
672 | err = security_shm_shmctl(NULL, cmd); |
673 | if (err) |
674 | return err; |
675 | |
676 | memset(&shminfo, 0, sizeof(shminfo)); |
677 | shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni; |
678 | shminfo.shmmax = ns->shm_ctlmax; |
679 | shminfo.shmall = ns->shm_ctlall; |
680 | |
681 | shminfo.shmmin = SHMMIN; |
682 | if(copy_shminfo_to_user (buf, &shminfo, version)) |
683 | return -EFAULT; |
684 | |
685 | down_read(&shm_ids(ns).rw_mutex); |
686 | err = ipc_get_maxid(&shm_ids(ns)); |
687 | up_read(&shm_ids(ns).rw_mutex); |
688 | |
689 | if(err<0) |
690 | err = 0; |
691 | goto out; |
692 | } |
693 | case SHM_INFO: |
694 | { |
695 | struct shm_info shm_info; |
696 | |
697 | err = security_shm_shmctl(NULL, cmd); |
698 | if (err) |
699 | return err; |
700 | |
701 | memset(&shm_info, 0, sizeof(shm_info)); |
702 | down_read(&shm_ids(ns).rw_mutex); |
703 | shm_info.used_ids = shm_ids(ns).in_use; |
704 | shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp); |
705 | shm_info.shm_tot = ns->shm_tot; |
706 | shm_info.swap_attempts = 0; |
707 | shm_info.swap_successes = 0; |
708 | err = ipc_get_maxid(&shm_ids(ns)); |
709 | up_read(&shm_ids(ns).rw_mutex); |
710 | if (copy_to_user(buf, &shm_info, sizeof(shm_info))) { |
711 | err = -EFAULT; |
712 | goto out; |
713 | } |
714 | |
715 | err = err < 0 ? 0 : err; |
716 | goto out; |
717 | } |
718 | case SHM_STAT: |
719 | case IPC_STAT: |
720 | { |
721 | struct shmid64_ds tbuf; |
722 | int result; |
723 | |
724 | if (cmd == SHM_STAT) { |
725 | shp = shm_lock(ns, shmid); |
726 | if (IS_ERR(shp)) { |
727 | err = PTR_ERR(shp); |
728 | goto out; |
729 | } |
730 | result = shp->shm_perm.id; |
731 | } else { |
732 | shp = shm_lock_check(ns, shmid); |
733 | if (IS_ERR(shp)) { |
734 | err = PTR_ERR(shp); |
735 | goto out; |
736 | } |
737 | result = 0; |
738 | } |
739 | err = -EACCES; |
740 | if (ipcperms (&shp->shm_perm, S_IRUGO)) |
741 | goto out_unlock; |
742 | err = security_shm_shmctl(shp, cmd); |
743 | if (err) |
744 | goto out_unlock; |
745 | memset(&tbuf, 0, sizeof(tbuf)); |
746 | kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm); |
747 | tbuf.shm_segsz = shp->shm_segsz; |
748 | tbuf.shm_atime = shp->shm_atim; |
749 | tbuf.shm_dtime = shp->shm_dtim; |
750 | tbuf.shm_ctime = shp->shm_ctim; |
751 | tbuf.shm_cpid = shp->shm_cprid; |
752 | tbuf.shm_lpid = shp->shm_lprid; |
753 | tbuf.shm_nattch = shp->shm_nattch; |
754 | shm_unlock(shp); |
755 | if(copy_shmid_to_user (buf, &tbuf, version)) |
756 | err = -EFAULT; |
757 | else |
758 | err = result; |
759 | goto out; |
760 | } |
761 | case SHM_LOCK: |
762 | case SHM_UNLOCK: |
763 | { |
764 | struct file *uninitialized_var(shm_file); |
765 | |
766 | lru_add_drain_all(); /* drain pagevecs to lru lists */ |
767 | |
768 | shp = shm_lock_check(ns, shmid); |
769 | if (IS_ERR(shp)) { |
770 | err = PTR_ERR(shp); |
771 | goto out; |
772 | } |
773 | |
774 | audit_ipc_obj(&(shp->shm_perm)); |
775 | |
776 | if (!capable(CAP_IPC_LOCK)) { |
777 | uid_t euid = current_euid(); |
778 | err = -EPERM; |
779 | if (euid != shp->shm_perm.uid && |
780 | euid != shp->shm_perm.cuid) |
781 | goto out_unlock; |
782 | if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK)) |
783 | goto out_unlock; |
784 | } |
785 | |
786 | err = security_shm_shmctl(shp, cmd); |
787 | if (err) |
788 | goto out_unlock; |
789 | |
790 | if(cmd==SHM_LOCK) { |
791 | struct user_struct *user = current_user(); |
792 | if (!is_file_hugepages(shp->shm_file)) { |
793 | err = shmem_lock(shp->shm_file, 1, user); |
794 | if (!err && !(shp->shm_perm.mode & SHM_LOCKED)){ |
795 | shp->shm_perm.mode |= SHM_LOCKED; |
796 | shp->mlock_user = user; |
797 | } |
798 | } |
799 | } else if (!is_file_hugepages(shp->shm_file)) { |
800 | shmem_lock(shp->shm_file, 0, shp->mlock_user); |
801 | shp->shm_perm.mode &= ~SHM_LOCKED; |
802 | shp->mlock_user = NULL; |
803 | } |
804 | shm_unlock(shp); |
805 | goto out; |
806 | } |
807 | case IPC_RMID: |
808 | case IPC_SET: |
809 | err = shmctl_down(ns, shmid, cmd, buf, version); |
810 | return err; |
811 | default: |
812 | return -EINVAL; |
813 | } |
814 | |
815 | out_unlock: |
816 | shm_unlock(shp); |
817 | out: |
818 | return err; |
819 | } |
820 | |
821 | /* |
822 | * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists. |
823 | * |
824 | * NOTE! Despite the name, this is NOT a direct system call entrypoint. The |
825 | * "raddr" thing points to kernel space, and there has to be a wrapper around |
826 | * this. |
827 | */ |
828 | long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr) |
829 | { |
830 | struct shmid_kernel *shp; |
831 | unsigned long addr; |
832 | unsigned long size; |
833 | struct file * file; |
834 | int err; |
835 | unsigned long flags; |
836 | unsigned long prot; |
837 | int acc_mode; |
838 | unsigned long user_addr; |
839 | struct ipc_namespace *ns; |
840 | struct shm_file_data *sfd; |
841 | struct path path; |
842 | fmode_t f_mode; |
843 | |
844 | err = -EINVAL; |
845 | if (shmid < 0) |
846 | goto out; |
847 | else if ((addr = (ulong)shmaddr)) { |
848 | if (addr & (SHMLBA-1)) { |
849 | if (shmflg & SHM_RND) |
850 | addr &= ~(SHMLBA-1); /* round down */ |
851 | else |
852 | #ifndef __ARCH_FORCE_SHMLBA |
853 | if (addr & ~PAGE_MASK) |
854 | #endif |
855 | goto out; |
856 | } |
857 | flags = MAP_SHARED | MAP_FIXED; |
858 | } else { |
859 | if ((shmflg & SHM_REMAP)) |
860 | goto out; |
861 | |
862 | flags = MAP_SHARED; |
863 | } |
864 | |
865 | if (shmflg & SHM_RDONLY) { |
866 | prot = PROT_READ; |
867 | acc_mode = S_IRUGO; |
868 | f_mode = FMODE_READ; |
869 | } else { |
870 | prot = PROT_READ | PROT_WRITE; |
871 | acc_mode = S_IRUGO | S_IWUGO; |
872 | f_mode = FMODE_READ | FMODE_WRITE; |
873 | } |
874 | if (shmflg & SHM_EXEC) { |
875 | prot |= PROT_EXEC; |
876 | acc_mode |= S_IXUGO; |
877 | } |
878 | |
879 | /* |
880 | * We cannot rely on the fs check since SYSV IPC does have an |
881 | * additional creator id... |
882 | */ |
883 | ns = current->nsproxy->ipc_ns; |
884 | shp = shm_lock_check(ns, shmid); |
885 | if (IS_ERR(shp)) { |
886 | err = PTR_ERR(shp); |
887 | goto out; |
888 | } |
889 | |
890 | err = -EACCES; |
891 | if (ipcperms(&shp->shm_perm, acc_mode)) |
892 | goto out_unlock; |
893 | |
894 | err = security_shm_shmat(shp, shmaddr, shmflg); |
895 | if (err) |
896 | goto out_unlock; |
897 | |
898 | path = shp->shm_file->f_path; |
899 | path_get(&path); |
900 | shp->shm_nattch++; |
901 | size = i_size_read(path.dentry->d_inode); |
902 | shm_unlock(shp); |
903 | |
904 | err = -ENOMEM; |
905 | sfd = kzalloc(sizeof(*sfd), GFP_KERNEL); |
906 | if (!sfd) |
907 | goto out_put_dentry; |
908 | |
909 | file = alloc_file(&path, f_mode, |
910 | is_file_hugepages(shp->shm_file) ? |
911 | &shm_file_operations_huge : |
912 | &shm_file_operations); |
913 | if (!file) |
914 | goto out_free; |
915 | |
916 | file->private_data = sfd; |
917 | file->f_mapping = shp->shm_file->f_mapping; |
918 | sfd->id = shp->shm_perm.id; |
919 | sfd->ns = get_ipc_ns(ns); |
920 | sfd->file = shp->shm_file; |
921 | sfd->vm_ops = NULL; |
922 | |
923 | down_write(¤t->mm->mmap_sem); |
924 | if (addr && !(shmflg & SHM_REMAP)) { |
925 | err = -EINVAL; |
926 | if (find_vma_intersection(current->mm, addr, addr + size)) |
927 | goto invalid; |
928 | /* |
929 | * If shm segment goes below stack, make sure there is some |
930 | * space left for the stack to grow (at least 4 pages). |
931 | */ |
932 | if (addr < current->mm->start_stack && |
933 | addr > current->mm->start_stack - size - PAGE_SIZE * 5) |
934 | goto invalid; |
935 | } |
936 | |
937 | user_addr = do_mmap (file, addr, size, prot, flags, 0); |
938 | *raddr = user_addr; |
939 | err = 0; |
940 | if (IS_ERR_VALUE(user_addr)) |
941 | err = (long)user_addr; |
942 | invalid: |
943 | up_write(¤t->mm->mmap_sem); |
944 | |
945 | fput(file); |
946 | |
947 | out_nattch: |
948 | down_write(&shm_ids(ns).rw_mutex); |
949 | shp = shm_lock(ns, shmid); |
950 | BUG_ON(IS_ERR(shp)); |
951 | shp->shm_nattch--; |
952 | if(shp->shm_nattch == 0 && |
953 | shp->shm_perm.mode & SHM_DEST) |
954 | shm_destroy(ns, shp); |
955 | else |
956 | shm_unlock(shp); |
957 | up_write(&shm_ids(ns).rw_mutex); |
958 | |
959 | out: |
960 | return err; |
961 | |
962 | out_unlock: |
963 | shm_unlock(shp); |
964 | goto out; |
965 | |
966 | out_free: |
967 | kfree(sfd); |
968 | out_put_dentry: |
969 | path_put(&path); |
970 | goto out_nattch; |
971 | } |
972 | |
973 | SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg) |
974 | { |
975 | unsigned long ret; |
976 | long err; |
977 | |
978 | err = do_shmat(shmid, shmaddr, shmflg, &ret); |
979 | if (err) |
980 | return err; |
981 | force_successful_syscall_return(); |
982 | return (long)ret; |
983 | } |
984 | |
985 | /* |
986 | * detach and kill segment if marked destroyed. |
987 | * The work is done in shm_close. |
988 | */ |
989 | SYSCALL_DEFINE1(shmdt, char __user *, shmaddr) |
990 | { |
991 | struct mm_struct *mm = current->mm; |
992 | struct vm_area_struct *vma; |
993 | unsigned long addr = (unsigned long)shmaddr; |
994 | int retval = -EINVAL; |
995 | #ifdef CONFIG_MMU |
996 | loff_t size = 0; |
997 | struct vm_area_struct *next; |
998 | #endif |
999 | |
1000 | if (addr & ~PAGE_MASK) |
1001 | return retval; |
1002 | |
1003 | down_write(&mm->mmap_sem); |
1004 | |
1005 | /* |
1006 | * This function tries to be smart and unmap shm segments that |
1007 | * were modified by partial mlock or munmap calls: |
1008 | * - It first determines the size of the shm segment that should be |
1009 | * unmapped: It searches for a vma that is backed by shm and that |
1010 | * started at address shmaddr. It records it's size and then unmaps |
1011 | * it. |
1012 | * - Then it unmaps all shm vmas that started at shmaddr and that |
1013 | * are within the initially determined size. |
1014 | * Errors from do_munmap are ignored: the function only fails if |
1015 | * it's called with invalid parameters or if it's called to unmap |
1016 | * a part of a vma. Both calls in this function are for full vmas, |
1017 | * the parameters are directly copied from the vma itself and always |
1018 | * valid - therefore do_munmap cannot fail. (famous last words?) |
1019 | */ |
1020 | /* |
1021 | * If it had been mremap()'d, the starting address would not |
1022 | * match the usual checks anyway. So assume all vma's are |
1023 | * above the starting address given. |
1024 | */ |
1025 | vma = find_vma(mm, addr); |
1026 | |
1027 | #ifdef CONFIG_MMU |
1028 | while (vma) { |
1029 | next = vma->vm_next; |
1030 | |
1031 | /* |
1032 | * Check if the starting address would match, i.e. it's |
1033 | * a fragment created by mprotect() and/or munmap(), or it |
1034 | * otherwise it starts at this address with no hassles. |
1035 | */ |
1036 | if ((vma->vm_ops == &shm_vm_ops) && |
1037 | (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) { |
1038 | |
1039 | |
1040 | size = vma->vm_file->f_path.dentry->d_inode->i_size; |
1041 | do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start); |
1042 | /* |
1043 | * We discovered the size of the shm segment, so |
1044 | * break out of here and fall through to the next |
1045 | * loop that uses the size information to stop |
1046 | * searching for matching vma's. |
1047 | */ |
1048 | retval = 0; |
1049 | vma = next; |
1050 | break; |
1051 | } |
1052 | vma = next; |
1053 | } |
1054 | |
1055 | /* |
1056 | * We need look no further than the maximum address a fragment |
1057 | * could possibly have landed at. Also cast things to loff_t to |
1058 | * prevent overflows and make comparisions vs. equal-width types. |
1059 | */ |
1060 | size = PAGE_ALIGN(size); |
1061 | while (vma && (loff_t)(vma->vm_end - addr) <= size) { |
1062 | next = vma->vm_next; |
1063 | |
1064 | /* finding a matching vma now does not alter retval */ |
1065 | if ((vma->vm_ops == &shm_vm_ops) && |
1066 | (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) |
1067 | |
1068 | do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start); |
1069 | vma = next; |
1070 | } |
1071 | |
1072 | #else /* CONFIG_MMU */ |
1073 | /* under NOMMU conditions, the exact address to be destroyed must be |
1074 | * given */ |
1075 | retval = -EINVAL; |
1076 | if (vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) { |
1077 | do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start); |
1078 | retval = 0; |
1079 | } |
1080 | |
1081 | #endif |
1082 | |
1083 | up_write(&mm->mmap_sem); |
1084 | return retval; |
1085 | } |
1086 | |
1087 | #ifdef CONFIG_PROC_FS |
1088 | static int sysvipc_shm_proc_show(struct seq_file *s, void *it) |
1089 | { |
1090 | struct shmid_kernel *shp = it; |
1091 | unsigned long rss = 0, swp = 0; |
1092 | |
1093 | shm_add_rss_swap(shp, &rss, &swp); |
1094 | |
1095 | #if BITS_PER_LONG <= 32 |
1096 | #define SIZE_SPEC "%10lu" |
1097 | #else |
1098 | #define SIZE_SPEC "%21lu" |
1099 | #endif |
1100 | |
1101 | return seq_printf(s, |
1102 | "%10d %10d %4o " SIZE_SPEC " %5u %5u " |
1103 | "%5lu %5u %5u %5u %5u %10lu %10lu %10lu " |
1104 | SIZE_SPEC " " SIZE_SPEC "\n", |
1105 | shp->shm_perm.key, |
1106 | shp->shm_perm.id, |
1107 | shp->shm_perm.mode, |
1108 | shp->shm_segsz, |
1109 | shp->shm_cprid, |
1110 | shp->shm_lprid, |
1111 | shp->shm_nattch, |
1112 | shp->shm_perm.uid, |
1113 | shp->shm_perm.gid, |
1114 | shp->shm_perm.cuid, |
1115 | shp->shm_perm.cgid, |
1116 | shp->shm_atim, |
1117 | shp->shm_dtim, |
1118 | shp->shm_ctim, |
1119 | rss * PAGE_SIZE, |
1120 | swp * PAGE_SIZE); |
1121 | } |
1122 | #endif |
1123 |
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