Merge branch 'master' into next
[linux-2.6.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
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 #include <linux/ima.h>
43
44 #include <asm/uaccess.h>
45
46 #include "util.h"
47
48 struct shm_file_data {
49         int id;
50         struct ipc_namespace *ns;
51         struct file *file;
52         const struct vm_operations_struct *vm_ops;
53 };
54
55 #define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data))
56
57 static const struct file_operations shm_file_operations;
58 static struct vm_operations_struct shm_vm_ops;
59
60 #define shm_ids(ns)     ((ns)->ids[IPC_SHM_IDS])
61
62 #define shm_unlock(shp)                 \
63         ipc_unlock(&(shp)->shm_perm)
64
65 static int newseg(struct ipc_namespace *, struct ipc_params *);
66 static void shm_open(struct vm_area_struct *vma);
67 static void shm_close(struct vm_area_struct *vma);
68 static void shm_destroy (struct ipc_namespace *ns, struct shmid_kernel *shp);
69 #ifdef CONFIG_PROC_FS
70 static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
71 #endif
72
73 void shm_init_ns(struct ipc_namespace *ns)
74 {
75         ns->shm_ctlmax = SHMMAX;
76         ns->shm_ctlall = SHMALL;
77         ns->shm_ctlmni = SHMMNI;
78         ns->shm_tot = 0;
79         ipc_init_ids(&shm_ids(ns));
80 }
81
82 /*
83  * Called with shm_ids.rw_mutex (writer) and the shp structure locked.
84  * Only shm_ids.rw_mutex remains locked on exit.
85  */
86 static void do_shm_rmid(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
87 {
88         struct shmid_kernel *shp;
89         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
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 #ifdef CONFIG_IPC_NS
101 void shm_exit_ns(struct ipc_namespace *ns)
102 {
103         free_ipcs(ns, &shm_ids(ns), do_shm_rmid);
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                                 "       key      shmid perms       size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime\n",
112                                 IPC_SHM_IDS, sysvipc_shm_proc_show);
113 }
114
115 /*
116  * shm_lock_(check_) routines are called in the paths where the rw_mutex
117  * is not necessarily held.
118  */
119 static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
120 {
121         struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id);
122
123         if (IS_ERR(ipcp))
124                 return (struct shmid_kernel *)ipcp;
125
126         return container_of(ipcp, struct shmid_kernel, shm_perm);
127 }
128
129 static inline struct shmid_kernel *shm_lock_check(struct ipc_namespace *ns,
130                                                 int id)
131 {
132         struct kern_ipc_perm *ipcp = ipc_lock_check(&shm_ids(ns), id);
133
134         if (IS_ERR(ipcp))
135                 return (struct shmid_kernel *)ipcp;
136
137         return container_of(ipcp, struct shmid_kernel, shm_perm);
138 }
139
140 static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
141 {
142         ipc_rmid(&shm_ids(ns), &s->shm_perm);
143 }
144
145
146 /* This is called by fork, once for every shm attach. */
147 static void shm_open(struct vm_area_struct *vma)
148 {
149         struct file *file = vma->vm_file;
150         struct shm_file_data *sfd = shm_file_data(file);
151         struct shmid_kernel *shp;
152
153         shp = shm_lock(sfd->ns, sfd->id);
154         BUG_ON(IS_ERR(shp));
155         shp->shm_atim = get_seconds();
156         shp->shm_lprid = task_tgid_vnr(current);
157         shp->shm_nattch++;
158         shm_unlock(shp);
159 }
160
161 /*
162  * shm_destroy - free the struct shmid_kernel
163  *
164  * @ns: namespace
165  * @shp: struct to free
166  *
167  * It has to be called with shp and shm_ids.rw_mutex (writer) locked,
168  * but returns with shp unlocked and freed.
169  */
170 static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
171 {
172         ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
173         shm_rmid(ns, shp);
174         shm_unlock(shp);
175         if (!is_file_hugepages(shp->shm_file))
176                 shmem_lock(shp->shm_file, 0, shp->mlock_user);
177         else
178                 user_shm_unlock(shp->shm_file->f_path.dentry->d_inode->i_size,
179                                                 shp->mlock_user);
180         fput (shp->shm_file);
181         security_shm_free(shp);
182         ipc_rcu_putref(shp);
183 }
184
185 /*
186  * remove the attach descriptor vma.
187  * free memory for segment if it is marked destroyed.
188  * The descriptor has already been removed from the current->mm->mmap list
189  * and will later be kfree()d.
190  */
191 static void shm_close(struct vm_area_struct *vma)
192 {
193         struct file * file = vma->vm_file;
194         struct shm_file_data *sfd = shm_file_data(file);
195         struct shmid_kernel *shp;
196         struct ipc_namespace *ns = sfd->ns;
197
198         down_write(&shm_ids(ns).rw_mutex);
199         /* remove from the list of attaches of the shm segment */
200         shp = shm_lock(ns, sfd->id);
201         BUG_ON(IS_ERR(shp));
202         shp->shm_lprid = task_tgid_vnr(current);
203         shp->shm_dtim = get_seconds();
204         shp->shm_nattch--;
205         if(shp->shm_nattch == 0 &&
206            shp->shm_perm.mode & SHM_DEST)
207                 shm_destroy(ns, shp);
208         else
209                 shm_unlock(shp);
210         up_write(&shm_ids(ns).rw_mutex);
211 }
212
213 static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
214 {
215         struct file *file = vma->vm_file;
216         struct shm_file_data *sfd = shm_file_data(file);
217
218         return sfd->vm_ops->fault(vma, vmf);
219 }
220
221 #ifdef CONFIG_NUMA
222 static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
223 {
224         struct file *file = vma->vm_file;
225         struct shm_file_data *sfd = shm_file_data(file);
226         int err = 0;
227         if (sfd->vm_ops->set_policy)
228                 err = sfd->vm_ops->set_policy(vma, new);
229         return err;
230 }
231
232 static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
233                                         unsigned long addr)
234 {
235         struct file *file = vma->vm_file;
236         struct shm_file_data *sfd = shm_file_data(file);
237         struct mempolicy *pol = NULL;
238
239         if (sfd->vm_ops->get_policy)
240                 pol = sfd->vm_ops->get_policy(vma, addr);
241         else if (vma->vm_policy)
242                 pol = vma->vm_policy;
243
244         return pol;
245 }
246 #endif
247
248 static int shm_mmap(struct file * file, struct vm_area_struct * vma)
249 {
250         struct shm_file_data *sfd = shm_file_data(file);
251         int ret;
252
253         ret = sfd->file->f_op->mmap(sfd->file, vma);
254         if (ret != 0)
255                 return ret;
256         sfd->vm_ops = vma->vm_ops;
257 #ifdef CONFIG_MMU
258         BUG_ON(!sfd->vm_ops->fault);
259 #endif
260         vma->vm_ops = &shm_vm_ops;
261         shm_open(vma);
262
263         return ret;
264 }
265
266 static int shm_release(struct inode *ino, struct file *file)
267 {
268         struct shm_file_data *sfd = shm_file_data(file);
269
270         put_ipc_ns(sfd->ns);
271         shm_file_data(file) = NULL;
272         kfree(sfd);
273         return 0;
274 }
275
276 static int shm_fsync(struct file *file, struct dentry *dentry, int datasync)
277 {
278         int (*fsync) (struct file *, struct dentry *, int datasync);
279         struct shm_file_data *sfd = shm_file_data(file);
280         int ret = -EINVAL;
281
282         fsync = sfd->file->f_op->fsync;
283         if (fsync)
284                 ret = fsync(sfd->file, sfd->file->f_path.dentry, datasync);
285         return ret;
286 }
287
288 static unsigned long shm_get_unmapped_area(struct file *file,
289         unsigned long addr, unsigned long len, unsigned long pgoff,
290         unsigned long flags)
291 {
292         struct shm_file_data *sfd = shm_file_data(file);
293         return get_unmapped_area(sfd->file, addr, len, pgoff, flags);
294 }
295
296 int is_file_shm_hugepages(struct file *file)
297 {
298         int ret = 0;
299
300         if (file->f_op == &shm_file_operations) {
301                 struct shm_file_data *sfd;
302                 sfd = shm_file_data(file);
303                 ret = is_file_hugepages(sfd->file);
304         }
305         return ret;
306 }
307
308 static const struct file_operations shm_file_operations = {
309         .mmap           = shm_mmap,
310         .fsync          = shm_fsync,
311         .release        = shm_release,
312         .get_unmapped_area      = shm_get_unmapped_area,
313 };
314
315 static struct vm_operations_struct shm_vm_ops = {
316         .open   = shm_open,     /* callback for a new vm-area open */
317         .close  = shm_close,    /* callback for when the vm-area is released */
318         .fault  = shm_fault,
319 #if defined(CONFIG_NUMA)
320         .set_policy = shm_set_policy,
321         .get_policy = shm_get_policy,
322 #endif
323 };
324
325 /**
326  * newseg - Create a new shared memory segment
327  * @ns: namespace
328  * @params: ptr to the structure that contains key, size and shmflg
329  *
330  * Called with shm_ids.rw_mutex held as a writer.
331  */
332
333 static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
334 {
335         key_t key = params->key;
336         int shmflg = params->flg;
337         size_t size = params->u.size;
338         int error;
339         struct shmid_kernel *shp;
340         int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
341         struct file * file;
342         char name[13];
343         int id;
344         int acctflag = 0;
345
346         if (size < SHMMIN || size > ns->shm_ctlmax)
347                 return -EINVAL;
348
349         if (ns->shm_tot + numpages > ns->shm_ctlall)
350                 return -ENOSPC;
351
352         shp = ipc_rcu_alloc(sizeof(*shp));
353         if (!shp)
354                 return -ENOMEM;
355
356         shp->shm_perm.key = key;
357         shp->shm_perm.mode = (shmflg & S_IRWXUGO);
358         shp->mlock_user = NULL;
359
360         shp->shm_perm.security = NULL;
361         error = security_shm_alloc(shp);
362         if (error) {
363                 ipc_rcu_putref(shp);
364                 return error;
365         }
366
367         sprintf (name, "SYSV%08x", key);
368         if (shmflg & SHM_HUGETLB) {
369                 /* hugetlb_file_setup applies strict accounting */
370                 if (shmflg & SHM_NORESERVE)
371                         acctflag = VM_NORESERVE;
372                 file = hugetlb_file_setup(name, size, acctflag);
373                 shp->mlock_user = current_user();
374         } else {
375                 /*
376                  * Do not allow no accounting for OVERCOMMIT_NEVER, even
377                  * if it's asked for.
378                  */
379                 if  ((shmflg & SHM_NORESERVE) &&
380                                 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
381                         acctflag = VM_NORESERVE;
382                 file = shmem_file_setup(name, size, acctflag);
383         }
384         error = PTR_ERR(file);
385         if (IS_ERR(file))
386                 goto no_file;
387         ima_shm_check(file);
388
389         id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
390         if (id < 0) {
391                 error = id;
392                 goto no_id;
393         }
394
395         shp->shm_cprid = task_tgid_vnr(current);
396         shp->shm_lprid = 0;
397         shp->shm_atim = shp->shm_dtim = 0;
398         shp->shm_ctim = get_seconds();
399         shp->shm_segsz = size;
400         shp->shm_nattch = 0;
401         shp->shm_file = file;
402         /*
403          * shmid gets reported as "inode#" in /proc/pid/maps.
404          * proc-ps tools use this. Changing this will break them.
405          */
406         file->f_dentry->d_inode->i_ino = shp->shm_perm.id;
407
408         ns->shm_tot += numpages;
409         error = shp->shm_perm.id;
410         shm_unlock(shp);
411         return error;
412
413 no_id:
414         fput(file);
415 no_file:
416         security_shm_free(shp);
417         ipc_rcu_putref(shp);
418         return error;
419 }
420
421 /*
422  * Called with shm_ids.rw_mutex and ipcp locked.
423  */
424 static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)
425 {
426         struct shmid_kernel *shp;
427
428         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
429         return security_shm_associate(shp, shmflg);
430 }
431
432 /*
433  * Called with shm_ids.rw_mutex and ipcp locked.
434  */
435 static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
436                                 struct ipc_params *params)
437 {
438         struct shmid_kernel *shp;
439
440         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
441         if (shp->shm_segsz < params->u.size)
442                 return -EINVAL;
443
444         return 0;
445 }
446
447 SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg)
448 {
449         struct ipc_namespace *ns;
450         struct ipc_ops shm_ops;
451         struct ipc_params shm_params;
452
453         ns = current->nsproxy->ipc_ns;
454
455         shm_ops.getnew = newseg;
456         shm_ops.associate = shm_security;
457         shm_ops.more_checks = shm_more_checks;
458
459         shm_params.key = key;
460         shm_params.flg = shmflg;
461         shm_params.u.size = size;
462
463         return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
464 }
465
466 static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
467 {
468         switch(version) {
469         case IPC_64:
470                 return copy_to_user(buf, in, sizeof(*in));
471         case IPC_OLD:
472             {
473                 struct shmid_ds out;
474
475                 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
476                 out.shm_segsz   = in->shm_segsz;
477                 out.shm_atime   = in->shm_atime;
478                 out.shm_dtime   = in->shm_dtime;
479                 out.shm_ctime   = in->shm_ctime;
480                 out.shm_cpid    = in->shm_cpid;
481                 out.shm_lpid    = in->shm_lpid;
482                 out.shm_nattch  = in->shm_nattch;
483
484                 return copy_to_user(buf, &out, sizeof(out));
485             }
486         default:
487                 return -EINVAL;
488         }
489 }
490
491 static inline unsigned long
492 copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version)
493 {
494         switch(version) {
495         case IPC_64:
496                 if (copy_from_user(out, buf, sizeof(*out)))
497                         return -EFAULT;
498                 return 0;
499         case IPC_OLD:
500             {
501                 struct shmid_ds tbuf_old;
502
503                 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
504                         return -EFAULT;
505
506                 out->shm_perm.uid       = tbuf_old.shm_perm.uid;
507                 out->shm_perm.gid       = tbuf_old.shm_perm.gid;
508                 out->shm_perm.mode      = tbuf_old.shm_perm.mode;
509
510                 return 0;
511             }
512         default:
513                 return -EINVAL;
514         }
515 }
516
517 static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
518 {
519         switch(version) {
520         case IPC_64:
521                 return copy_to_user(buf, in, sizeof(*in));
522         case IPC_OLD:
523             {
524                 struct shminfo out;
525
526                 if(in->shmmax > INT_MAX)
527                         out.shmmax = INT_MAX;
528                 else
529                         out.shmmax = (int)in->shmmax;
530
531                 out.shmmin      = in->shmmin;
532                 out.shmmni      = in->shmmni;
533                 out.shmseg      = in->shmseg;
534                 out.shmall      = in->shmall; 
535
536                 return copy_to_user(buf, &out, sizeof(out));
537             }
538         default:
539                 return -EINVAL;
540         }
541 }
542
543 /*
544  * Called with shm_ids.rw_mutex held as a reader
545  */
546 static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
547                 unsigned long *swp)
548 {
549         int next_id;
550         int total, in_use;
551
552         *rss = 0;
553         *swp = 0;
554
555         in_use = shm_ids(ns).in_use;
556
557         for (total = 0, next_id = 0; total < in_use; next_id++) {
558                 struct shmid_kernel *shp;
559                 struct inode *inode;
560
561                 shp = idr_find(&shm_ids(ns).ipcs_idr, next_id);
562                 if (shp == NULL)
563                         continue;
564
565                 inode = shp->shm_file->f_path.dentry->d_inode;
566
567                 if (is_file_hugepages(shp->shm_file)) {
568                         struct address_space *mapping = inode->i_mapping;
569                         struct hstate *h = hstate_file(shp->shm_file);
570                         *rss += pages_per_huge_page(h) * mapping->nrpages;
571                 } else {
572 #ifdef CONFIG_SHMEM
573                         struct shmem_inode_info *info = SHMEM_I(inode);
574                         spin_lock(&info->lock);
575                         *rss += inode->i_mapping->nrpages;
576                         *swp += info->swapped;
577                         spin_unlock(&info->lock);
578 #else
579                         *rss += inode->i_mapping->nrpages;
580 #endif
581                 }
582
583                 total++;
584         }
585 }
586
587 /*
588  * This function handles some shmctl commands which require the rw_mutex
589  * to be held in write mode.
590  * NOTE: no locks must be held, the rw_mutex is taken inside this function.
591  */
592 static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
593                        struct shmid_ds __user *buf, int version)
594 {
595         struct kern_ipc_perm *ipcp;
596         struct shmid64_ds shmid64;
597         struct shmid_kernel *shp;
598         int err;
599
600         if (cmd == IPC_SET) {
601                 if (copy_shmid_from_user(&shmid64, buf, version))
602                         return -EFAULT;
603         }
604
605         ipcp = ipcctl_pre_down(&shm_ids(ns), shmid, cmd, &shmid64.shm_perm, 0);
606         if (IS_ERR(ipcp))
607                 return PTR_ERR(ipcp);
608
609         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
610
611         err = security_shm_shmctl(shp, cmd);
612         if (err)
613                 goto out_unlock;
614         switch (cmd) {
615         case IPC_RMID:
616                 do_shm_rmid(ns, ipcp);
617                 goto out_up;
618         case IPC_SET:
619                 ipc_update_perm(&shmid64.shm_perm, ipcp);
620                 shp->shm_ctim = get_seconds();
621                 break;
622         default:
623                 err = -EINVAL;
624         }
625 out_unlock:
626         shm_unlock(shp);
627 out_up:
628         up_write(&shm_ids(ns).rw_mutex);
629         return err;
630 }
631
632 SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
633 {
634         struct shmid_kernel *shp;
635         int err, version;
636         struct ipc_namespace *ns;
637
638         if (cmd < 0 || shmid < 0) {
639                 err = -EINVAL;
640                 goto out;
641         }
642
643         version = ipc_parse_version(&cmd);
644         ns = current->nsproxy->ipc_ns;
645
646         switch (cmd) { /* replace with proc interface ? */
647         case IPC_INFO:
648         {
649                 struct shminfo64 shminfo;
650
651                 err = security_shm_shmctl(NULL, cmd);
652                 if (err)
653                         return err;
654
655                 memset(&shminfo, 0, sizeof(shminfo));
656                 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
657                 shminfo.shmmax = ns->shm_ctlmax;
658                 shminfo.shmall = ns->shm_ctlall;
659
660                 shminfo.shmmin = SHMMIN;
661                 if(copy_shminfo_to_user (buf, &shminfo, version))
662                         return -EFAULT;
663
664                 down_read(&shm_ids(ns).rw_mutex);
665                 err = ipc_get_maxid(&shm_ids(ns));
666                 up_read(&shm_ids(ns).rw_mutex);
667
668                 if(err<0)
669                         err = 0;
670                 goto out;
671         }
672         case SHM_INFO:
673         {
674                 struct shm_info shm_info;
675
676                 err = security_shm_shmctl(NULL, cmd);
677                 if (err)
678                         return err;
679
680                 memset(&shm_info, 0, sizeof(shm_info));
681                 down_read(&shm_ids(ns).rw_mutex);
682                 shm_info.used_ids = shm_ids(ns).in_use;
683                 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
684                 shm_info.shm_tot = ns->shm_tot;
685                 shm_info.swap_attempts = 0;
686                 shm_info.swap_successes = 0;
687                 err = ipc_get_maxid(&shm_ids(ns));
688                 up_read(&shm_ids(ns).rw_mutex);
689                 if (copy_to_user(buf, &shm_info, sizeof(shm_info))) {
690                         err = -EFAULT;
691                         goto out;
692                 }
693
694                 err = err < 0 ? 0 : err;
695                 goto out;
696         }
697         case SHM_STAT:
698         case IPC_STAT:
699         {
700                 struct shmid64_ds tbuf;
701                 int result;
702
703                 if (cmd == SHM_STAT) {
704                         shp = shm_lock(ns, shmid);
705                         if (IS_ERR(shp)) {
706                                 err = PTR_ERR(shp);
707                                 goto out;
708                         }
709                         result = shp->shm_perm.id;
710                 } else {
711                         shp = shm_lock_check(ns, shmid);
712                         if (IS_ERR(shp)) {
713                                 err = PTR_ERR(shp);
714                                 goto out;
715                         }
716                         result = 0;
717                 }
718                 err = -EACCES;
719                 if (ipcperms (&shp->shm_perm, S_IRUGO))
720                         goto out_unlock;
721                 err = security_shm_shmctl(shp, cmd);
722                 if (err)
723                         goto out_unlock;
724                 memset(&tbuf, 0, sizeof(tbuf));
725                 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
726                 tbuf.shm_segsz  = shp->shm_segsz;
727                 tbuf.shm_atime  = shp->shm_atim;
728                 tbuf.shm_dtime  = shp->shm_dtim;
729                 tbuf.shm_ctime  = shp->shm_ctim;
730                 tbuf.shm_cpid   = shp->shm_cprid;
731                 tbuf.shm_lpid   = shp->shm_lprid;
732                 tbuf.shm_nattch = shp->shm_nattch;
733                 shm_unlock(shp);
734                 if(copy_shmid_to_user (buf, &tbuf, version))
735                         err = -EFAULT;
736                 else
737                         err = result;
738                 goto out;
739         }
740         case SHM_LOCK:
741         case SHM_UNLOCK:
742         {
743                 struct file *uninitialized_var(shm_file);
744
745                 lru_add_drain_all();  /* drain pagevecs to lru lists */
746
747                 shp = shm_lock_check(ns, shmid);
748                 if (IS_ERR(shp)) {
749                         err = PTR_ERR(shp);
750                         goto out;
751                 }
752
753                 audit_ipc_obj(&(shp->shm_perm));
754
755                 if (!capable(CAP_IPC_LOCK)) {
756                         uid_t euid = current_euid();
757                         err = -EPERM;
758                         if (euid != shp->shm_perm.uid &&
759                             euid != shp->shm_perm.cuid)
760                                 goto out_unlock;
761                         if (cmd == SHM_LOCK &&
762                             !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur)
763                                 goto out_unlock;
764                 }
765
766                 err = security_shm_shmctl(shp, cmd);
767                 if (err)
768                         goto out_unlock;
769                 
770                 if(cmd==SHM_LOCK) {
771                         struct user_struct *user = current_user();
772                         if (!is_file_hugepages(shp->shm_file)) {
773                                 err = shmem_lock(shp->shm_file, 1, user);
774                                 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)){
775                                         shp->shm_perm.mode |= SHM_LOCKED;
776                                         shp->mlock_user = user;
777                                 }
778                         }
779                 } else if (!is_file_hugepages(shp->shm_file)) {
780                         shmem_lock(shp->shm_file, 0, shp->mlock_user);
781                         shp->shm_perm.mode &= ~SHM_LOCKED;
782                         shp->mlock_user = NULL;
783                 }
784                 shm_unlock(shp);
785                 goto out;
786         }
787         case IPC_RMID:
788         case IPC_SET:
789                 err = shmctl_down(ns, shmid, cmd, buf, version);
790                 return err;
791         default:
792                 return -EINVAL;
793         }
794
795 out_unlock:
796         shm_unlock(shp);
797 out:
798         return err;
799 }
800
801 /*
802  * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
803  *
804  * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
805  * "raddr" thing points to kernel space, and there has to be a wrapper around
806  * this.
807  */
808 long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
809 {
810         struct shmid_kernel *shp;
811         unsigned long addr;
812         unsigned long size;
813         struct file * file;
814         int    err;
815         unsigned long flags;
816         unsigned long prot;
817         int acc_mode;
818         unsigned long user_addr;
819         struct ipc_namespace *ns;
820         struct shm_file_data *sfd;
821         struct path path;
822         fmode_t f_mode;
823
824         err = -EINVAL;
825         if (shmid < 0)
826                 goto out;
827         else if ((addr = (ulong)shmaddr)) {
828                 if (addr & (SHMLBA-1)) {
829                         if (shmflg & SHM_RND)
830                                 addr &= ~(SHMLBA-1);       /* round down */
831                         else
832 #ifndef __ARCH_FORCE_SHMLBA
833                                 if (addr & ~PAGE_MASK)
834 #endif
835                                         goto out;
836                 }
837                 flags = MAP_SHARED | MAP_FIXED;
838         } else {
839                 if ((shmflg & SHM_REMAP))
840                         goto out;
841
842                 flags = MAP_SHARED;
843         }
844
845         if (shmflg & SHM_RDONLY) {
846                 prot = PROT_READ;
847                 acc_mode = S_IRUGO;
848                 f_mode = FMODE_READ;
849         } else {
850                 prot = PROT_READ | PROT_WRITE;
851                 acc_mode = S_IRUGO | S_IWUGO;
852                 f_mode = FMODE_READ | FMODE_WRITE;
853         }
854         if (shmflg & SHM_EXEC) {
855                 prot |= PROT_EXEC;
856                 acc_mode |= S_IXUGO;
857         }
858
859         /*
860          * We cannot rely on the fs check since SYSV IPC does have an
861          * additional creator id...
862          */
863         ns = current->nsproxy->ipc_ns;
864         shp = shm_lock_check(ns, shmid);
865         if (IS_ERR(shp)) {
866                 err = PTR_ERR(shp);
867                 goto out;
868         }
869
870         err = -EACCES;
871         if (ipcperms(&shp->shm_perm, acc_mode))
872                 goto out_unlock;
873
874         err = security_shm_shmat(shp, shmaddr, shmflg);
875         if (err)
876                 goto out_unlock;
877
878         path.dentry = dget(shp->shm_file->f_path.dentry);
879         path.mnt    = shp->shm_file->f_path.mnt;
880         shp->shm_nattch++;
881         size = i_size_read(path.dentry->d_inode);
882         shm_unlock(shp);
883
884         err = -ENOMEM;
885         sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
886         if (!sfd)
887                 goto out_put_dentry;
888
889         file = alloc_file(path.mnt, path.dentry, f_mode, &shm_file_operations);
890         if (!file)
891                 goto out_free;
892         ima_shm_check(file);
893
894         file->private_data = sfd;
895         file->f_mapping = shp->shm_file->f_mapping;
896         sfd->id = shp->shm_perm.id;
897         sfd->ns = get_ipc_ns(ns);
898         sfd->file = shp->shm_file;
899         sfd->vm_ops = NULL;
900
901         down_write(&current->mm->mmap_sem);
902         if (addr && !(shmflg & SHM_REMAP)) {
903                 err = -EINVAL;
904                 if (find_vma_intersection(current->mm, addr, addr + size))
905                         goto invalid;
906                 /*
907                  * If shm segment goes below stack, make sure there is some
908                  * space left for the stack to grow (at least 4 pages).
909                  */
910                 if (addr < current->mm->start_stack &&
911                     addr > current->mm->start_stack - size - PAGE_SIZE * 5)
912                         goto invalid;
913         }
914                 
915         user_addr = do_mmap (file, addr, size, prot, flags, 0);
916         *raddr = user_addr;
917         err = 0;
918         if (IS_ERR_VALUE(user_addr))
919                 err = (long)user_addr;
920 invalid:
921         up_write(&current->mm->mmap_sem);
922
923         fput(file);
924
925 out_nattch:
926         down_write(&shm_ids(ns).rw_mutex);
927         shp = shm_lock(ns, shmid);
928         BUG_ON(IS_ERR(shp));
929         shp->shm_nattch--;
930         if(shp->shm_nattch == 0 &&
931            shp->shm_perm.mode & SHM_DEST)
932                 shm_destroy(ns, shp);
933         else
934                 shm_unlock(shp);
935         up_write(&shm_ids(ns).rw_mutex);
936
937 out:
938         return err;
939
940 out_unlock:
941         shm_unlock(shp);
942         goto out;
943
944 out_free:
945         kfree(sfd);
946 out_put_dentry:
947         dput(path.dentry);
948         goto out_nattch;
949 }
950
951 SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg)
952 {
953         unsigned long ret;
954         long err;
955
956         err = do_shmat(shmid, shmaddr, shmflg, &ret);
957         if (err)
958                 return err;
959         force_successful_syscall_return();
960         return (long)ret;
961 }
962
963 /*
964  * detach and kill segment if marked destroyed.
965  * The work is done in shm_close.
966  */
967 SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
968 {
969         struct mm_struct *mm = current->mm;
970         struct vm_area_struct *vma, *next;
971         unsigned long addr = (unsigned long)shmaddr;
972         loff_t size = 0;
973         int retval = -EINVAL;
974
975         if (addr & ~PAGE_MASK)
976                 return retval;
977
978         down_write(&mm->mmap_sem);
979
980         /*
981          * This function tries to be smart and unmap shm segments that
982          * were modified by partial mlock or munmap calls:
983          * - It first determines the size of the shm segment that should be
984          *   unmapped: It searches for a vma that is backed by shm and that
985          *   started at address shmaddr. It records it's size and then unmaps
986          *   it.
987          * - Then it unmaps all shm vmas that started at shmaddr and that
988          *   are within the initially determined size.
989          * Errors from do_munmap are ignored: the function only fails if
990          * it's called with invalid parameters or if it's called to unmap
991          * a part of a vma. Both calls in this function are for full vmas,
992          * the parameters are directly copied from the vma itself and always
993          * valid - therefore do_munmap cannot fail. (famous last words?)
994          */
995         /*
996          * If it had been mremap()'d, the starting address would not
997          * match the usual checks anyway. So assume all vma's are
998          * above the starting address given.
999          */
1000         vma = find_vma(mm, addr);
1001
1002 #ifdef CONFIG_MMU
1003         while (vma) {
1004                 next = vma->vm_next;
1005
1006                 /*
1007                  * Check if the starting address would match, i.e. it's
1008                  * a fragment created by mprotect() and/or munmap(), or it
1009                  * otherwise it starts at this address with no hassles.
1010                  */
1011                 if ((vma->vm_ops == &shm_vm_ops) &&
1012                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1013
1014
1015                         size = vma->vm_file->f_path.dentry->d_inode->i_size;
1016                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1017                         /*
1018                          * We discovered the size of the shm segment, so
1019                          * break out of here and fall through to the next
1020                          * loop that uses the size information to stop
1021                          * searching for matching vma's.
1022                          */
1023                         retval = 0;
1024                         vma = next;
1025                         break;
1026                 }
1027                 vma = next;
1028         }
1029
1030         /*
1031          * We need look no further than the maximum address a fragment
1032          * could possibly have landed at. Also cast things to loff_t to
1033          * prevent overflows and make comparisions vs. equal-width types.
1034          */
1035         size = PAGE_ALIGN(size);
1036         while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1037                 next = vma->vm_next;
1038
1039                 /* finding a matching vma now does not alter retval */
1040                 if ((vma->vm_ops == &shm_vm_ops) &&
1041                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1042
1043                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1044                 vma = next;
1045         }
1046
1047 #else /* CONFIG_MMU */
1048         /* under NOMMU conditions, the exact address to be destroyed must be
1049          * given */
1050         retval = -EINVAL;
1051         if (vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) {
1052                 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1053                 retval = 0;
1054         }
1055
1056 #endif
1057
1058         up_write(&mm->mmap_sem);
1059         return retval;
1060 }
1061
1062 #ifdef CONFIG_PROC_FS
1063 static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1064 {
1065         struct shmid_kernel *shp = it;
1066
1067 #if BITS_PER_LONG <= 32
1068 #define SIZE_SPEC "%10lu"
1069 #else
1070 #define SIZE_SPEC "%21lu"
1071 #endif
1072
1073         return seq_printf(s,
1074                           "%10d %10d  %4o " SIZE_SPEC " %5u %5u  "
1075                           "%5lu %5u %5u %5u %5u %10lu %10lu %10lu\n",
1076                           shp->shm_perm.key,
1077                           shp->shm_perm.id,
1078                           shp->shm_perm.mode,
1079                           shp->shm_segsz,
1080                           shp->shm_cprid,
1081                           shp->shm_lprid,
1082                           shp->shm_nattch,
1083                           shp->shm_perm.uid,
1084                           shp->shm_perm.gid,
1085                           shp->shm_perm.cuid,
1086                           shp->shm_perm.cgid,
1087                           shp->shm_atim,
1088                           shp->shm_dtim,
1089                           shp->shm_ctim);
1090 }
1091 #endif