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[linux-3.10.git] / ipc / shm.c
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  * Better ipc lock (kern_ipc_perm.lock) handling
24  * Davidlohr Bueso <davidlohr.bueso@hp.com>, June 2013.
25  */
26
27 #include <linux/slab.h>
28 #include <linux/mm.h>
29 #include <linux/hugetlb.h>
30 #include <linux/shm.h>
31 #include <linux/init.h>
32 #include <linux/file.h>
33 #include <linux/mman.h>
34 #include <linux/shmem_fs.h>
35 #include <linux/security.h>
36 #include <linux/syscalls.h>
37 #include <linux/audit.h>
38 #include <linux/capability.h>
39 #include <linux/ptrace.h>
40 #include <linux/seq_file.h>
41 #include <linux/rwsem.h>
42 #include <linux/nsproxy.h>
43 #include <linux/mount.h>
44 #include <linux/ipc_namespace.h>
45
46 #include <asm/uaccess.h>
47
48 #include "util.h"
49
50 struct shm_file_data {
51         int id;
52         struct ipc_namespace *ns;
53         struct file *file;
54         const struct vm_operations_struct *vm_ops;
55 };
56
57 #define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data))
58
59 static const struct file_operations shm_file_operations;
60 static const struct vm_operations_struct shm_vm_ops;
61
62 #define shm_ids(ns)     ((ns)->ids[IPC_SHM_IDS])
63
64 #define shm_unlock(shp)                 \
65         ipc_unlock(&(shp)->shm_perm)
66
67 static int newseg(struct ipc_namespace *, struct ipc_params *);
68 static void shm_open(struct vm_area_struct *vma);
69 static void shm_close(struct vm_area_struct *vma);
70 static void shm_destroy (struct ipc_namespace *ns, struct shmid_kernel *shp);
71 #ifdef CONFIG_PROC_FS
72 static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
73 #endif
74
75 void shm_init_ns(struct ipc_namespace *ns)
76 {
77         ns->shm_ctlmax = SHMMAX;
78         ns->shm_ctlall = SHMALL;
79         ns->shm_ctlmni = SHMMNI;
80         ns->shm_rmid_forced = 0;
81         ns->shm_tot = 0;
82         ipc_init_ids(&shm_ids(ns));
83 }
84
85 /*
86  * Called with shm_ids.rwsem (writer) and the shp structure locked.
87  * Only shm_ids.rwsem remains locked on exit.
88  */
89 static void do_shm_rmid(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
90 {
91         struct shmid_kernel *shp;
92         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
93
94         if (shp->shm_nattch){
95                 shp->shm_perm.mode |= SHM_DEST;
96                 /* Do not find it any more */
97                 shp->shm_perm.key = IPC_PRIVATE;
98                 shm_unlock(shp);
99         } else
100                 shm_destroy(ns, shp);
101 }
102
103 #ifdef CONFIG_IPC_NS
104 void shm_exit_ns(struct ipc_namespace *ns)
105 {
106         free_ipcs(ns, &shm_ids(ns), do_shm_rmid);
107         idr_destroy(&ns->ids[IPC_SHM_IDS].ipcs_idr);
108 }
109 #endif
110
111 static int __init ipc_ns_init(void)
112 {
113         shm_init_ns(&init_ipc_ns);
114         return 0;
115 }
116
117 pure_initcall(ipc_ns_init);
118
119 void __init shm_init (void)
120 {
121         ipc_init_proc_interface("sysvipc/shm",
122 #if BITS_PER_LONG <= 32
123                                 "       key      shmid perms       size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime        rss       swap\n",
124 #else
125                                 "       key      shmid perms                  size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime                   rss                  swap\n",
126 #endif
127                                 IPC_SHM_IDS, sysvipc_shm_proc_show);
128 }
129
130 static inline struct shmid_kernel *shm_obtain_object(struct ipc_namespace *ns, int id)
131 {
132         struct kern_ipc_perm *ipcp = ipc_obtain_object(&shm_ids(ns), id);
133
134         if (IS_ERR(ipcp))
135                 return ERR_CAST(ipcp);
136
137         return container_of(ipcp, struct shmid_kernel, shm_perm);
138 }
139
140 static inline struct shmid_kernel *shm_obtain_object_check(struct ipc_namespace *ns, int id)
141 {
142         struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&shm_ids(ns), id);
143
144         if (IS_ERR(ipcp))
145                 return ERR_CAST(ipcp);
146
147         return container_of(ipcp, struct shmid_kernel, shm_perm);
148 }
149
150 /*
151  * shm_lock_(check_) routines are called in the paths where the rwsem
152  * is not necessarily held.
153  */
154 static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
155 {
156         struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id);
157
158         if (IS_ERR(ipcp))
159                 return (struct shmid_kernel *)ipcp;
160
161         return container_of(ipcp, struct shmid_kernel, shm_perm);
162 }
163
164 static inline void shm_lock_by_ptr(struct shmid_kernel *ipcp)
165 {
166         rcu_read_lock();
167         ipc_lock_object(&ipcp->shm_perm);
168 }
169
170 static void shm_rcu_free(struct rcu_head *head)
171 {
172         struct ipc_rcu *p = container_of(head, struct ipc_rcu, rcu);
173         struct shmid_kernel *shp = ipc_rcu_to_struct(p);
174
175         security_shm_free(shp);
176         ipc_rcu_free(head);
177 }
178
179 static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
180 {
181         ipc_rmid(&shm_ids(ns), &s->shm_perm);
182 }
183
184
185 /* This is called by fork, once for every shm attach. */
186 static void shm_open(struct vm_area_struct *vma)
187 {
188         struct file *file = vma->vm_file;
189         struct shm_file_data *sfd = shm_file_data(file);
190         struct shmid_kernel *shp;
191
192         shp = shm_lock(sfd->ns, sfd->id);
193         BUG_ON(IS_ERR(shp));
194         shp->shm_atim = get_seconds();
195         shp->shm_lprid = task_tgid_vnr(current);
196         shp->shm_nattch++;
197         shm_unlock(shp);
198 }
199
200 /*
201  * shm_destroy - free the struct shmid_kernel
202  *
203  * @ns: namespace
204  * @shp: struct to free
205  *
206  * It has to be called with shp and shm_ids.rwsem (writer) locked,
207  * but returns with shp unlocked and freed.
208  */
209 static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
210 {
211         struct file *shm_file;
212
213         shm_file = shp->shm_file;
214         shp->shm_file = NULL;
215         ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
216         shm_rmid(ns, shp);
217         shm_unlock(shp);
218         if (!is_file_hugepages(shm_file))
219                 shmem_lock(shm_file, 0, shp->mlock_user);
220         else if (shp->mlock_user)
221                 user_shm_unlock(file_inode(shm_file)->i_size, shp->mlock_user);
222         fput(shm_file);
223         ipc_rcu_putref(shp, shm_rcu_free);
224 }
225
226 /*
227  * shm_may_destroy - identifies whether shm segment should be destroyed now
228  *
229  * Returns true if and only if there are no active users of the segment and
230  * one of the following is true:
231  *
232  * 1) shmctl(id, IPC_RMID, NULL) was called for this shp
233  *
234  * 2) sysctl kernel.shm_rmid_forced is set to 1.
235  */
236 static bool shm_may_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
237 {
238         return (shp->shm_nattch == 0) &&
239                (ns->shm_rmid_forced ||
240                 (shp->shm_perm.mode & SHM_DEST));
241 }
242
243 /*
244  * remove the attach descriptor vma.
245  * free memory for segment if it is marked destroyed.
246  * The descriptor has already been removed from the current->mm->mmap list
247  * and will later be kfree()d.
248  */
249 static void shm_close(struct vm_area_struct *vma)
250 {
251         struct file * file = vma->vm_file;
252         struct shm_file_data *sfd = shm_file_data(file);
253         struct shmid_kernel *shp;
254         struct ipc_namespace *ns = sfd->ns;
255
256         down_write(&shm_ids(ns).rwsem);
257         /* remove from the list of attaches of the shm segment */
258         shp = shm_lock(ns, sfd->id);
259         BUG_ON(IS_ERR(shp));
260         shp->shm_lprid = task_tgid_vnr(current);
261         shp->shm_dtim = get_seconds();
262         shp->shm_nattch--;
263         if (shm_may_destroy(ns, shp))
264                 shm_destroy(ns, shp);
265         else
266                 shm_unlock(shp);
267         up_write(&shm_ids(ns).rwsem);
268 }
269
270 /* Called with ns->shm_ids(ns).rwsem locked */
271 static int shm_try_destroy_current(int id, void *p, void *data)
272 {
273         struct ipc_namespace *ns = data;
274         struct kern_ipc_perm *ipcp = p;
275         struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
276
277         if (shp->shm_creator != current)
278                 return 0;
279
280         /*
281          * Mark it as orphaned to destroy the segment when
282          * kernel.shm_rmid_forced is changed.
283          * It is noop if the following shm_may_destroy() returns true.
284          */
285         shp->shm_creator = NULL;
286
287         /*
288          * Don't even try to destroy it.  If shm_rmid_forced=0 and IPC_RMID
289          * is not set, it shouldn't be deleted here.
290          */
291         if (!ns->shm_rmid_forced)
292                 return 0;
293
294         if (shm_may_destroy(ns, shp)) {
295                 shm_lock_by_ptr(shp);
296                 shm_destroy(ns, shp);
297         }
298         return 0;
299 }
300
301 /* Called with ns->shm_ids(ns).rwsem locked */
302 static int shm_try_destroy_orphaned(int id, void *p, void *data)
303 {
304         struct ipc_namespace *ns = data;
305         struct kern_ipc_perm *ipcp = p;
306         struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
307
308         /*
309          * We want to destroy segments without users and with already
310          * exit'ed originating process.
311          *
312          * As shp->* are changed under rwsem, it's safe to skip shp locking.
313          */
314         if (shp->shm_creator != NULL)
315                 return 0;
316
317         if (shm_may_destroy(ns, shp)) {
318                 shm_lock_by_ptr(shp);
319                 shm_destroy(ns, shp);
320         }
321         return 0;
322 }
323
324 void shm_destroy_orphaned(struct ipc_namespace *ns)
325 {
326         down_write(&shm_ids(ns).rwsem);
327         if (shm_ids(ns).in_use)
328                 idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_orphaned, ns);
329         up_write(&shm_ids(ns).rwsem);
330 }
331
332
333 void exit_shm(struct task_struct *task)
334 {
335         struct ipc_namespace *ns = task->nsproxy->ipc_ns;
336
337         if (shm_ids(ns).in_use == 0)
338                 return;
339
340         /* Destroy all already created segments, but not mapped yet */
341         down_write(&shm_ids(ns).rwsem);
342         if (shm_ids(ns).in_use)
343                 idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_current, ns);
344         up_write(&shm_ids(ns).rwsem);
345 }
346
347 static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
348 {
349         struct file *file = vma->vm_file;
350         struct shm_file_data *sfd = shm_file_data(file);
351
352         return sfd->vm_ops->fault(vma, vmf);
353 }
354
355 #ifdef CONFIG_NUMA
356 static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
357 {
358         struct file *file = vma->vm_file;
359         struct shm_file_data *sfd = shm_file_data(file);
360         int err = 0;
361         if (sfd->vm_ops->set_policy)
362                 err = sfd->vm_ops->set_policy(vma, new);
363         return err;
364 }
365
366 static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
367                                         unsigned long addr)
368 {
369         struct file *file = vma->vm_file;
370         struct shm_file_data *sfd = shm_file_data(file);
371         struct mempolicy *pol = NULL;
372
373         if (sfd->vm_ops->get_policy)
374                 pol = sfd->vm_ops->get_policy(vma, addr);
375         else if (vma->vm_policy)
376                 pol = vma->vm_policy;
377
378         return pol;
379 }
380 #endif
381
382 static int shm_mmap(struct file * file, struct vm_area_struct * vma)
383 {
384         struct shm_file_data *sfd = shm_file_data(file);
385         int ret;
386
387         ret = sfd->file->f_op->mmap(sfd->file, vma);
388         if (ret != 0)
389                 return ret;
390         sfd->vm_ops = vma->vm_ops;
391 #ifdef CONFIG_MMU
392         BUG_ON(!sfd->vm_ops->fault);
393 #endif
394         vma->vm_ops = &shm_vm_ops;
395         shm_open(vma);
396
397         return ret;
398 }
399
400 static int shm_release(struct inode *ino, struct file *file)
401 {
402         struct shm_file_data *sfd = shm_file_data(file);
403
404         put_ipc_ns(sfd->ns);
405         shm_file_data(file) = NULL;
406         kfree(sfd);
407         return 0;
408 }
409
410 static int shm_fsync(struct file *file, loff_t start, loff_t end, int datasync)
411 {
412         struct shm_file_data *sfd = shm_file_data(file);
413
414         if (!sfd->file->f_op->fsync)
415                 return -EINVAL;
416         return sfd->file->f_op->fsync(sfd->file, start, end, datasync);
417 }
418
419 static long shm_fallocate(struct file *file, int mode, loff_t offset,
420                           loff_t len)
421 {
422         struct shm_file_data *sfd = shm_file_data(file);
423
424         if (!sfd->file->f_op->fallocate)
425                 return -EOPNOTSUPP;
426         return sfd->file->f_op->fallocate(file, mode, offset, len);
427 }
428
429 static unsigned long shm_get_unmapped_area(struct file *file,
430         unsigned long addr, unsigned long len, unsigned long pgoff,
431         unsigned long flags)
432 {
433         struct shm_file_data *sfd = shm_file_data(file);
434         return sfd->file->f_op->get_unmapped_area(sfd->file, addr, len,
435                                                 pgoff, flags);
436 }
437
438 static const struct file_operations shm_file_operations = {
439         .mmap           = shm_mmap,
440         .fsync          = shm_fsync,
441         .release        = shm_release,
442 #ifndef CONFIG_MMU
443         .get_unmapped_area      = shm_get_unmapped_area,
444 #endif
445         .llseek         = noop_llseek,
446         .fallocate      = shm_fallocate,
447 };
448
449 static const struct file_operations shm_file_operations_huge = {
450         .mmap           = shm_mmap,
451         .fsync          = shm_fsync,
452         .release        = shm_release,
453         .get_unmapped_area      = shm_get_unmapped_area,
454         .llseek         = noop_llseek,
455         .fallocate      = shm_fallocate,
456 };
457
458 int is_file_shm_hugepages(struct file *file)
459 {
460         return file->f_op == &shm_file_operations_huge;
461 }
462
463 static const struct vm_operations_struct shm_vm_ops = {
464         .open   = shm_open,     /* callback for a new vm-area open */
465         .close  = shm_close,    /* callback for when the vm-area is released */
466         .fault  = shm_fault,
467 #if defined(CONFIG_NUMA)
468         .set_policy = shm_set_policy,
469         .get_policy = shm_get_policy,
470 #endif
471 };
472
473 /**
474  * newseg - Create a new shared memory segment
475  * @ns: namespace
476  * @params: ptr to the structure that contains key, size and shmflg
477  *
478  * Called with shm_ids.rwsem held as a writer.
479  */
480
481 static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
482 {
483         key_t key = params->key;
484         int shmflg = params->flg;
485         size_t size = params->u.size;
486         int error;
487         struct shmid_kernel *shp;
488         size_t numpages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
489         struct file * file;
490         char name[13];
491         int id;
492         vm_flags_t acctflag = 0;
493
494         if (size < SHMMIN || size > ns->shm_ctlmax)
495                 return -EINVAL;
496
497         if (ns->shm_tot + numpages > ns->shm_ctlall)
498                 return -ENOSPC;
499
500         shp = ipc_rcu_alloc(sizeof(*shp));
501         if (!shp)
502                 return -ENOMEM;
503
504         shp->shm_perm.key = key;
505         shp->shm_perm.mode = (shmflg & S_IRWXUGO);
506         shp->mlock_user = NULL;
507
508         shp->shm_perm.security = NULL;
509         error = security_shm_alloc(shp);
510         if (error) {
511                 ipc_rcu_putref(shp, ipc_rcu_free);
512                 return error;
513         }
514
515         sprintf (name, "SYSV%08x", key);
516         if (shmflg & SHM_HUGETLB) {
517                 struct hstate *hs = hstate_sizelog((shmflg >> SHM_HUGE_SHIFT)
518                                                 & SHM_HUGE_MASK);
519                 size_t hugesize;
520
521                 if (!hs) {
522                         error = -EINVAL;
523                         goto no_file;
524                 }
525                 hugesize = ALIGN(size, huge_page_size(hs));
526
527                 /* hugetlb_file_setup applies strict accounting */
528                 if (shmflg & SHM_NORESERVE)
529                         acctflag = VM_NORESERVE;
530                 file = hugetlb_file_setup(name, hugesize, acctflag,
531                                   &shp->mlock_user, HUGETLB_SHMFS_INODE,
532                                 (shmflg >> SHM_HUGE_SHIFT) & SHM_HUGE_MASK);
533         } else {
534                 /*
535                  * Do not allow no accounting for OVERCOMMIT_NEVER, even
536                  * if it's asked for.
537                  */
538                 if  ((shmflg & SHM_NORESERVE) &&
539                                 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
540                         acctflag = VM_NORESERVE;
541                 file = shmem_file_setup(name, size, acctflag);
542         }
543         error = PTR_ERR(file);
544         if (IS_ERR(file))
545                 goto no_file;
546
547         id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
548         if (id < 0) {
549                 error = id;
550                 goto no_id;
551         }
552
553         shp->shm_cprid = task_tgid_vnr(current);
554         shp->shm_lprid = 0;
555         shp->shm_atim = shp->shm_dtim = 0;
556         shp->shm_ctim = get_seconds();
557         shp->shm_segsz = size;
558         shp->shm_nattch = 0;
559         shp->shm_file = file;
560         shp->shm_creator = current;
561
562         /*
563          * shmid gets reported as "inode#" in /proc/pid/maps.
564          * proc-ps tools use this. Changing this will break them.
565          */
566         file_inode(file)->i_ino = shp->shm_perm.id;
567
568         ns->shm_tot += numpages;
569         error = shp->shm_perm.id;
570
571         ipc_unlock_object(&shp->shm_perm);
572         rcu_read_unlock();
573         return error;
574
575 no_id:
576         if (is_file_hugepages(file) && shp->mlock_user)
577                 user_shm_unlock(size, shp->mlock_user);
578         fput(file);
579 no_file:
580         ipc_rcu_putref(shp, shm_rcu_free);
581         return error;
582 }
583
584 /*
585  * Called with shm_ids.rwsem and ipcp locked.
586  */
587 static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)
588 {
589         struct shmid_kernel *shp;
590
591         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
592         return security_shm_associate(shp, shmflg);
593 }
594
595 /*
596  * Called with shm_ids.rwsem and ipcp locked.
597  */
598 static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
599                                 struct ipc_params *params)
600 {
601         struct shmid_kernel *shp;
602
603         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
604         if (shp->shm_segsz < params->u.size)
605                 return -EINVAL;
606
607         return 0;
608 }
609
610 SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg)
611 {
612         struct ipc_namespace *ns;
613         struct ipc_ops shm_ops;
614         struct ipc_params shm_params;
615
616         ns = current->nsproxy->ipc_ns;
617
618         shm_ops.getnew = newseg;
619         shm_ops.associate = shm_security;
620         shm_ops.more_checks = shm_more_checks;
621
622         shm_params.key = key;
623         shm_params.flg = shmflg;
624         shm_params.u.size = size;
625
626         return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
627 }
628
629 static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
630 {
631         switch(version) {
632         case IPC_64:
633                 return copy_to_user(buf, in, sizeof(*in));
634         case IPC_OLD:
635             {
636                 struct shmid_ds out;
637
638                 memset(&out, 0, sizeof(out));
639                 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
640                 out.shm_segsz   = in->shm_segsz;
641                 out.shm_atime   = in->shm_atime;
642                 out.shm_dtime   = in->shm_dtime;
643                 out.shm_ctime   = in->shm_ctime;
644                 out.shm_cpid    = in->shm_cpid;
645                 out.shm_lpid    = in->shm_lpid;
646                 out.shm_nattch  = in->shm_nattch;
647
648                 return copy_to_user(buf, &out, sizeof(out));
649             }
650         default:
651                 return -EINVAL;
652         }
653 }
654
655 static inline unsigned long
656 copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version)
657 {
658         switch(version) {
659         case IPC_64:
660                 if (copy_from_user(out, buf, sizeof(*out)))
661                         return -EFAULT;
662                 return 0;
663         case IPC_OLD:
664             {
665                 struct shmid_ds tbuf_old;
666
667                 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
668                         return -EFAULT;
669
670                 out->shm_perm.uid       = tbuf_old.shm_perm.uid;
671                 out->shm_perm.gid       = tbuf_old.shm_perm.gid;
672                 out->shm_perm.mode      = tbuf_old.shm_perm.mode;
673
674                 return 0;
675             }
676         default:
677                 return -EINVAL;
678         }
679 }
680
681 static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
682 {
683         switch(version) {
684         case IPC_64:
685                 return copy_to_user(buf, in, sizeof(*in));
686         case IPC_OLD:
687             {
688                 struct shminfo out;
689
690                 if(in->shmmax > INT_MAX)
691                         out.shmmax = INT_MAX;
692                 else
693                         out.shmmax = (int)in->shmmax;
694
695                 out.shmmin      = in->shmmin;
696                 out.shmmni      = in->shmmni;
697                 out.shmseg      = in->shmseg;
698                 out.shmall      = in->shmall; 
699
700                 return copy_to_user(buf, &out, sizeof(out));
701             }
702         default:
703                 return -EINVAL;
704         }
705 }
706
707 /*
708  * Calculate and add used RSS and swap pages of a shm.
709  * Called with shm_ids.rwsem held as a reader
710  */
711 static void shm_add_rss_swap(struct shmid_kernel *shp,
712         unsigned long *rss_add, unsigned long *swp_add)
713 {
714         struct inode *inode;
715
716         inode = file_inode(shp->shm_file);
717
718         if (is_file_hugepages(shp->shm_file)) {
719                 struct address_space *mapping = inode->i_mapping;
720                 struct hstate *h = hstate_file(shp->shm_file);
721                 *rss_add += pages_per_huge_page(h) * mapping->nrpages;
722         } else {
723 #ifdef CONFIG_SHMEM
724                 struct shmem_inode_info *info = SHMEM_I(inode);
725                 spin_lock(&info->lock);
726                 *rss_add += inode->i_mapping->nrpages;
727                 *swp_add += info->swapped;
728                 spin_unlock(&info->lock);
729 #else
730                 *rss_add += inode->i_mapping->nrpages;
731 #endif
732         }
733 }
734
735 /*
736  * Called with shm_ids.rwsem held as a reader
737  */
738 static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
739                 unsigned long *swp)
740 {
741         int next_id;
742         int total, in_use;
743
744         *rss = 0;
745         *swp = 0;
746
747         in_use = shm_ids(ns).in_use;
748
749         for (total = 0, next_id = 0; total < in_use; next_id++) {
750                 struct kern_ipc_perm *ipc;
751                 struct shmid_kernel *shp;
752
753                 ipc = idr_find(&shm_ids(ns).ipcs_idr, next_id);
754                 if (ipc == NULL)
755                         continue;
756                 shp = container_of(ipc, struct shmid_kernel, shm_perm);
757
758                 shm_add_rss_swap(shp, rss, swp);
759
760                 total++;
761         }
762 }
763
764 /*
765  * This function handles some shmctl commands which require the rwsem
766  * to be held in write mode.
767  * NOTE: no locks must be held, the rwsem is taken inside this function.
768  */
769 static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
770                        struct shmid_ds __user *buf, int version)
771 {
772         struct kern_ipc_perm *ipcp;
773         struct shmid64_ds shmid64;
774         struct shmid_kernel *shp;
775         int err;
776
777         if (cmd == IPC_SET) {
778                 if (copy_shmid_from_user(&shmid64, buf, version))
779                         return -EFAULT;
780         }
781
782         down_write(&shm_ids(ns).rwsem);
783         rcu_read_lock();
784
785         ipcp = ipcctl_pre_down_nolock(ns, &shm_ids(ns), shmid, cmd,
786                                       &shmid64.shm_perm, 0);
787         if (IS_ERR(ipcp)) {
788                 err = PTR_ERR(ipcp);
789                 goto out_unlock1;
790         }
791
792         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
793
794         err = security_shm_shmctl(shp, cmd);
795         if (err)
796                 goto out_unlock1;
797
798         switch (cmd) {
799         case IPC_RMID:
800                 ipc_lock_object(&shp->shm_perm);
801                 /* do_shm_rmid unlocks the ipc object and rcu */
802                 do_shm_rmid(ns, ipcp);
803                 goto out_up;
804         case IPC_SET:
805                 ipc_lock_object(&shp->shm_perm);
806                 err = ipc_update_perm(&shmid64.shm_perm, ipcp);
807                 if (err)
808                         goto out_unlock0;
809                 shp->shm_ctim = get_seconds();
810                 break;
811         default:
812                 err = -EINVAL;
813                 goto out_unlock1;
814         }
815
816 out_unlock0:
817         ipc_unlock_object(&shp->shm_perm);
818 out_unlock1:
819         rcu_read_unlock();
820 out_up:
821         up_write(&shm_ids(ns).rwsem);
822         return err;
823 }
824
825 static int shmctl_nolock(struct ipc_namespace *ns, int shmid,
826                          int cmd, int version, void __user *buf)
827 {
828         int err;
829         struct shmid_kernel *shp;
830
831         /* preliminary security checks for *_INFO */
832         if (cmd == IPC_INFO || cmd == SHM_INFO) {
833                 err = security_shm_shmctl(NULL, cmd);
834                 if (err)
835                         return err;
836         }
837
838         switch (cmd) {
839         case IPC_INFO:
840         {
841                 struct shminfo64 shminfo;
842
843                 memset(&shminfo, 0, sizeof(shminfo));
844                 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
845                 shminfo.shmmax = ns->shm_ctlmax;
846                 shminfo.shmall = ns->shm_ctlall;
847
848                 shminfo.shmmin = SHMMIN;
849                 if(copy_shminfo_to_user (buf, &shminfo, version))
850                         return -EFAULT;
851
852                 down_read(&shm_ids(ns).rwsem);
853                 err = ipc_get_maxid(&shm_ids(ns));
854                 up_read(&shm_ids(ns).rwsem);
855
856                 if(err<0)
857                         err = 0;
858                 goto out;
859         }
860         case SHM_INFO:
861         {
862                 struct shm_info shm_info;
863
864                 memset(&shm_info, 0, sizeof(shm_info));
865                 down_read(&shm_ids(ns).rwsem);
866                 shm_info.used_ids = shm_ids(ns).in_use;
867                 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
868                 shm_info.shm_tot = ns->shm_tot;
869                 shm_info.swap_attempts = 0;
870                 shm_info.swap_successes = 0;
871                 err = ipc_get_maxid(&shm_ids(ns));
872                 up_read(&shm_ids(ns).rwsem);
873                 if (copy_to_user(buf, &shm_info, sizeof(shm_info))) {
874                         err = -EFAULT;
875                         goto out;
876                 }
877
878                 err = err < 0 ? 0 : err;
879                 goto out;
880         }
881         case SHM_STAT:
882         case IPC_STAT:
883         {
884                 struct shmid64_ds tbuf;
885                 int result;
886
887                 rcu_read_lock();
888                 if (cmd == SHM_STAT) {
889                         shp = shm_obtain_object(ns, shmid);
890                         if (IS_ERR(shp)) {
891                                 err = PTR_ERR(shp);
892                                 goto out_unlock;
893                         }
894                         result = shp->shm_perm.id;
895                 } else {
896                         shp = shm_obtain_object_check(ns, shmid);
897                         if (IS_ERR(shp)) {
898                                 err = PTR_ERR(shp);
899                                 goto out_unlock;
900                         }
901                         result = 0;
902                 }
903
904                 err = -EACCES;
905                 if (ipcperms(ns, &shp->shm_perm, S_IRUGO))
906                         goto out_unlock;
907
908                 err = security_shm_shmctl(shp, cmd);
909                 if (err)
910                         goto out_unlock;
911
912                 memset(&tbuf, 0, sizeof(tbuf));
913                 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
914                 tbuf.shm_segsz  = shp->shm_segsz;
915                 tbuf.shm_atime  = shp->shm_atim;
916                 tbuf.shm_dtime  = shp->shm_dtim;
917                 tbuf.shm_ctime  = shp->shm_ctim;
918                 tbuf.shm_cpid   = shp->shm_cprid;
919                 tbuf.shm_lpid   = shp->shm_lprid;
920                 tbuf.shm_nattch = shp->shm_nattch;
921                 rcu_read_unlock();
922
923                 if (copy_shmid_to_user(buf, &tbuf, version))
924                         err = -EFAULT;
925                 else
926                         err = result;
927                 goto out;
928         }
929         default:
930                 return -EINVAL;
931         }
932
933 out_unlock:
934         rcu_read_unlock();
935 out:
936         return err;
937 }
938
939 SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
940 {
941         struct shmid_kernel *shp;
942         int err, version;
943         struct ipc_namespace *ns;
944
945         if (cmd < 0 || shmid < 0)
946                 return -EINVAL;
947
948         version = ipc_parse_version(&cmd);
949         ns = current->nsproxy->ipc_ns;
950
951         switch (cmd) {
952         case IPC_INFO:
953         case SHM_INFO:
954         case SHM_STAT:
955         case IPC_STAT:
956                 return shmctl_nolock(ns, shmid, cmd, version, buf);
957         case IPC_RMID:
958         case IPC_SET:
959                 return shmctl_down(ns, shmid, cmd, buf, version);
960         case SHM_LOCK:
961         case SHM_UNLOCK:
962         {
963                 struct file *shm_file;
964
965                 rcu_read_lock();
966                 shp = shm_obtain_object_check(ns, shmid);
967                 if (IS_ERR(shp)) {
968                         err = PTR_ERR(shp);
969                         goto out_unlock1;
970                 }
971
972                 audit_ipc_obj(&(shp->shm_perm));
973                 err = security_shm_shmctl(shp, cmd);
974                 if (err)
975                         goto out_unlock1;
976
977                 ipc_lock_object(&shp->shm_perm);
978                 if (!ns_capable(ns->user_ns, CAP_IPC_LOCK)) {
979                         kuid_t euid = current_euid();
980                         if (!uid_eq(euid, shp->shm_perm.uid) &&
981                             !uid_eq(euid, shp->shm_perm.cuid)) {
982                                 err = -EPERM;
983                                 goto out_unlock0;
984                         }
985                         if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK)) {
986                                 err = -EPERM;
987                                 goto out_unlock0;
988                         }
989                 }
990
991                 shm_file = shp->shm_file;
992
993                 /* check if shm_destroy() is tearing down shp */
994                 if (shm_file == NULL) {
995                         err = -EIDRM;
996                         goto out_unlock0;
997                 }
998
999                 if (is_file_hugepages(shm_file))
1000                         goto out_unlock0;
1001
1002                 if (cmd == SHM_LOCK) {
1003                         struct user_struct *user = current_user();
1004                         err = shmem_lock(shm_file, 1, user);
1005                         if (!err && !(shp->shm_perm.mode & SHM_LOCKED)) {
1006                                 shp->shm_perm.mode |= SHM_LOCKED;
1007                                 shp->mlock_user = user;
1008                         }
1009                         goto out_unlock0;
1010                 }
1011
1012                 /* SHM_UNLOCK */
1013                 if (!(shp->shm_perm.mode & SHM_LOCKED))
1014                         goto out_unlock0;
1015                 shmem_lock(shm_file, 0, shp->mlock_user);
1016                 shp->shm_perm.mode &= ~SHM_LOCKED;
1017                 shp->mlock_user = NULL;
1018                 get_file(shm_file);
1019                 ipc_unlock_object(&shp->shm_perm);
1020                 rcu_read_unlock();
1021                 shmem_unlock_mapping(shm_file->f_mapping);
1022
1023                 fput(shm_file);
1024                 return err;
1025         }
1026         default:
1027                 return -EINVAL;
1028         }
1029
1030 out_unlock0:
1031         ipc_unlock_object(&shp->shm_perm);
1032 out_unlock1:
1033         rcu_read_unlock();
1034         return err;
1035 }
1036
1037 /*
1038  * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
1039  *
1040  * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
1041  * "raddr" thing points to kernel space, and there has to be a wrapper around
1042  * this.
1043  */
1044 long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr,
1045               unsigned long shmlba)
1046 {
1047         struct shmid_kernel *shp;
1048         unsigned long addr;
1049         unsigned long size;
1050         struct file * file;
1051         int    err;
1052         unsigned long flags;
1053         unsigned long prot;
1054         int acc_mode;
1055         struct ipc_namespace *ns;
1056         struct shm_file_data *sfd;
1057         struct path path;
1058         fmode_t f_mode;
1059         unsigned long populate = 0;
1060
1061         err = -EINVAL;
1062         if (shmid < 0)
1063                 goto out;
1064         else if ((addr = (ulong)shmaddr)) {
1065                 if (addr & (shmlba - 1)) {
1066                         if (shmflg & SHM_RND)
1067                                 addr &= ~(shmlba - 1);     /* round down */
1068                         else
1069 #ifndef __ARCH_FORCE_SHMLBA
1070                                 if (addr & ~PAGE_MASK)
1071 #endif
1072                                         goto out;
1073                 }
1074                 flags = MAP_SHARED | MAP_FIXED;
1075         } else {
1076                 if ((shmflg & SHM_REMAP))
1077                         goto out;
1078
1079                 flags = MAP_SHARED;
1080         }
1081
1082         if (shmflg & SHM_RDONLY) {
1083                 prot = PROT_READ;
1084                 acc_mode = S_IRUGO;
1085                 f_mode = FMODE_READ;
1086         } else {
1087                 prot = PROT_READ | PROT_WRITE;
1088                 acc_mode = S_IRUGO | S_IWUGO;
1089                 f_mode = FMODE_READ | FMODE_WRITE;
1090         }
1091         if (shmflg & SHM_EXEC) {
1092                 prot |= PROT_EXEC;
1093                 acc_mode |= S_IXUGO;
1094         }
1095
1096         /*
1097          * We cannot rely on the fs check since SYSV IPC does have an
1098          * additional creator id...
1099          */
1100         ns = current->nsproxy->ipc_ns;
1101         rcu_read_lock();
1102         shp = shm_obtain_object_check(ns, shmid);
1103         if (IS_ERR(shp)) {
1104                 err = PTR_ERR(shp);
1105                 goto out_unlock;
1106         }
1107
1108         err = -EACCES;
1109         if (ipcperms(ns, &shp->shm_perm, acc_mode))
1110                 goto out_unlock;
1111
1112         err = security_shm_shmat(shp, shmaddr, shmflg);
1113         if (err)
1114                 goto out_unlock;
1115
1116         ipc_lock_object(&shp->shm_perm);
1117
1118         /* check if shm_destroy() is tearing down shp */
1119         if (shp->shm_file == NULL) {
1120                 ipc_unlock_object(&shp->shm_perm);
1121                 err = -EIDRM;
1122                 goto out_unlock;
1123         }
1124
1125         path = shp->shm_file->f_path;
1126         path_get(&path);
1127         shp->shm_nattch++;
1128         size = i_size_read(path.dentry->d_inode);
1129         ipc_unlock_object(&shp->shm_perm);
1130         rcu_read_unlock();
1131
1132         err = -ENOMEM;
1133         sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
1134         if (!sfd) {
1135                 path_put(&path);
1136                 goto out_nattch;
1137         }
1138
1139         file = alloc_file(&path, f_mode,
1140                           is_file_hugepages(shp->shm_file) ?
1141                                 &shm_file_operations_huge :
1142                                 &shm_file_operations);
1143         err = PTR_ERR(file);
1144         if (IS_ERR(file)) {
1145                 kfree(sfd);
1146                 path_put(&path);
1147                 goto out_nattch;
1148         }
1149
1150         file->private_data = sfd;
1151         file->f_mapping = shp->shm_file->f_mapping;
1152         sfd->id = shp->shm_perm.id;
1153         sfd->ns = get_ipc_ns(ns);
1154         sfd->file = shp->shm_file;
1155         sfd->vm_ops = NULL;
1156
1157         err = security_mmap_file(file, prot, flags);
1158         if (err)
1159                 goto out_fput;
1160
1161         down_write(&current->mm->mmap_sem);
1162         if (addr && !(shmflg & SHM_REMAP)) {
1163                 err = -EINVAL;
1164                 if (find_vma_intersection(current->mm, addr, addr + size))
1165                         goto invalid;
1166                 /*
1167                  * If shm segment goes below stack, make sure there is some
1168                  * space left for the stack to grow (at least 4 pages).
1169                  */
1170                 if (addr < current->mm->start_stack &&
1171                     addr > current->mm->start_stack - size - PAGE_SIZE * 5)
1172                         goto invalid;
1173         }
1174
1175         addr = do_mmap_pgoff(file, addr, size, prot, flags, 0, &populate);
1176         *raddr = addr;
1177         err = 0;
1178         if (IS_ERR_VALUE(addr))
1179                 err = (long)addr;
1180 invalid:
1181         up_write(&current->mm->mmap_sem);
1182         if (populate)
1183                 mm_populate(addr, populate);
1184
1185 out_fput:
1186         fput(file);
1187
1188 out_nattch:
1189         down_write(&shm_ids(ns).rwsem);
1190         shp = shm_lock(ns, shmid);
1191         BUG_ON(IS_ERR(shp));
1192         shp->shm_nattch--;
1193         if (shm_may_destroy(ns, shp))
1194                 shm_destroy(ns, shp);
1195         else
1196                 shm_unlock(shp);
1197         up_write(&shm_ids(ns).rwsem);
1198         return err;
1199
1200 out_unlock:
1201         rcu_read_unlock();
1202 out:
1203         return err;
1204 }
1205
1206 SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg)
1207 {
1208         unsigned long ret;
1209         long err;
1210
1211         err = do_shmat(shmid, shmaddr, shmflg, &ret, SHMLBA);
1212         if (err)
1213                 return err;
1214         force_successful_syscall_return();
1215         return (long)ret;
1216 }
1217
1218 /*
1219  * detach and kill segment if marked destroyed.
1220  * The work is done in shm_close.
1221  */
1222 SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
1223 {
1224         struct mm_struct *mm = current->mm;
1225         struct vm_area_struct *vma;
1226         unsigned long addr = (unsigned long)shmaddr;
1227         int retval = -EINVAL;
1228 #ifdef CONFIG_MMU
1229         loff_t size = 0;
1230         struct vm_area_struct *next;
1231 #endif
1232
1233         if (addr & ~PAGE_MASK)
1234                 return retval;
1235
1236         down_write(&mm->mmap_sem);
1237
1238         /*
1239          * This function tries to be smart and unmap shm segments that
1240          * were modified by partial mlock or munmap calls:
1241          * - It first determines the size of the shm segment that should be
1242          *   unmapped: It searches for a vma that is backed by shm and that
1243          *   started at address shmaddr. It records it's size and then unmaps
1244          *   it.
1245          * - Then it unmaps all shm vmas that started at shmaddr and that
1246          *   are within the initially determined size.
1247          * Errors from do_munmap are ignored: the function only fails if
1248          * it's called with invalid parameters or if it's called to unmap
1249          * a part of a vma. Both calls in this function are for full vmas,
1250          * the parameters are directly copied from the vma itself and always
1251          * valid - therefore do_munmap cannot fail. (famous last words?)
1252          */
1253         /*
1254          * If it had been mremap()'d, the starting address would not
1255          * match the usual checks anyway. So assume all vma's are
1256          * above the starting address given.
1257          */
1258         vma = find_vma(mm, addr);
1259
1260 #ifdef CONFIG_MMU
1261         while (vma) {
1262                 next = vma->vm_next;
1263
1264                 /*
1265                  * Check if the starting address would match, i.e. it's
1266                  * a fragment created by mprotect() and/or munmap(), or it
1267                  * otherwise it starts at this address with no hassles.
1268                  */
1269                 if ((vma->vm_ops == &shm_vm_ops) &&
1270                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1271
1272
1273                         size = file_inode(vma->vm_file)->i_size;
1274                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1275                         /*
1276                          * We discovered the size of the shm segment, so
1277                          * break out of here and fall through to the next
1278                          * loop that uses the size information to stop
1279                          * searching for matching vma's.
1280                          */
1281                         retval = 0;
1282                         vma = next;
1283                         break;
1284                 }
1285                 vma = next;
1286         }
1287
1288         /*
1289          * We need look no further than the maximum address a fragment
1290          * could possibly have landed at. Also cast things to loff_t to
1291          * prevent overflows and make comparisons vs. equal-width types.
1292          */
1293         size = PAGE_ALIGN(size);
1294         while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1295                 next = vma->vm_next;
1296
1297                 /* finding a matching vma now does not alter retval */
1298                 if ((vma->vm_ops == &shm_vm_ops) &&
1299                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1300
1301                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1302                 vma = next;
1303         }
1304
1305 #else /* CONFIG_MMU */
1306         /* under NOMMU conditions, the exact address to be destroyed must be
1307          * given */
1308         if (vma && vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) {
1309                 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1310                 retval = 0;
1311         }
1312
1313 #endif
1314
1315         up_write(&mm->mmap_sem);
1316         return retval;
1317 }
1318
1319 #ifdef CONFIG_PROC_FS
1320 static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1321 {
1322         struct user_namespace *user_ns = seq_user_ns(s);
1323         struct shmid_kernel *shp = it;
1324         unsigned long rss = 0, swp = 0;
1325
1326         shm_add_rss_swap(shp, &rss, &swp);
1327
1328 #if BITS_PER_LONG <= 32
1329 #define SIZE_SPEC "%10lu"
1330 #else
1331 #define SIZE_SPEC "%21lu"
1332 #endif
1333
1334         return seq_printf(s,
1335                           "%10d %10d  %4o " SIZE_SPEC " %5u %5u  "
1336                           "%5lu %5u %5u %5u %5u %10lu %10lu %10lu "
1337                           SIZE_SPEC " " SIZE_SPEC "\n",
1338                           shp->shm_perm.key,
1339                           shp->shm_perm.id,
1340                           shp->shm_perm.mode,
1341                           shp->shm_segsz,
1342                           shp->shm_cprid,
1343                           shp->shm_lprid,
1344                           shp->shm_nattch,
1345                           from_kuid_munged(user_ns, shp->shm_perm.uid),
1346                           from_kgid_munged(user_ns, shp->shm_perm.gid),
1347                           from_kuid_munged(user_ns, shp->shm_perm.cuid),
1348                           from_kgid_munged(user_ns, shp->shm_perm.cgid),
1349                           shp->shm_atim,
1350                           shp->shm_dtim,
1351                           shp->shm_ctim,
1352                           rss * PAGE_SIZE,
1353                           swp * PAGE_SIZE);
1354 }
1355 #endif