nommu: fix SYSV SHM for NOMMU
[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
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                                 "       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 if (shp->mlock_user)
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 sfd->file->f_op->get_unmapped_area(sfd->file, addr, len,
294                                                 pgoff, flags);
295 }
296
297 static const struct file_operations shm_file_operations = {
298         .mmap           = shm_mmap,
299         .fsync          = shm_fsync,
300         .release        = shm_release,
301 #ifndef CONFIG_MMU
302         .get_unmapped_area      = shm_get_unmapped_area,
303 #endif
304 };
305
306 static const struct file_operations shm_file_operations_huge = {
307         .mmap           = shm_mmap,
308         .fsync          = shm_fsync,
309         .release        = shm_release,
310         .get_unmapped_area      = shm_get_unmapped_area,
311 };
312
313 int is_file_shm_hugepages(struct file *file)
314 {
315         return file->f_op == &shm_file_operations_huge;
316 }
317
318 static const struct vm_operations_struct shm_vm_ops = {
319         .open   = shm_open,     /* callback for a new vm-area open */
320         .close  = shm_close,    /* callback for when the vm-area is released */
321         .fault  = shm_fault,
322 #if defined(CONFIG_NUMA)
323         .set_policy = shm_set_policy,
324         .get_policy = shm_get_policy,
325 #endif
326 };
327
328 /**
329  * newseg - Create a new shared memory segment
330  * @ns: namespace
331  * @params: ptr to the structure that contains key, size and shmflg
332  *
333  * Called with shm_ids.rw_mutex held as a writer.
334  */
335
336 static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
337 {
338         key_t key = params->key;
339         int shmflg = params->flg;
340         size_t size = params->u.size;
341         int error;
342         struct shmid_kernel *shp;
343         int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
344         struct file * file;
345         char name[13];
346         int id;
347         int acctflag = 0;
348
349         if (size < SHMMIN || size > ns->shm_ctlmax)
350                 return -EINVAL;
351
352         if (ns->shm_tot + numpages > ns->shm_ctlall)
353                 return -ENOSPC;
354
355         shp = ipc_rcu_alloc(sizeof(*shp));
356         if (!shp)
357                 return -ENOMEM;
358
359         shp->shm_perm.key = key;
360         shp->shm_perm.mode = (shmflg & S_IRWXUGO);
361         shp->mlock_user = NULL;
362
363         shp->shm_perm.security = NULL;
364         error = security_shm_alloc(shp);
365         if (error) {
366                 ipc_rcu_putref(shp);
367                 return error;
368         }
369
370         sprintf (name, "SYSV%08x", key);
371         if (shmflg & SHM_HUGETLB) {
372                 /* hugetlb_file_setup applies strict accounting */
373                 if (shmflg & SHM_NORESERVE)
374                         acctflag = VM_NORESERVE;
375                 file = hugetlb_file_setup(name, size, acctflag,
376                                         &shp->mlock_user, HUGETLB_SHMFS_INODE);
377         } else {
378                 /*
379                  * Do not allow no accounting for OVERCOMMIT_NEVER, even
380                  * if it's asked for.
381                  */
382                 if  ((shmflg & SHM_NORESERVE) &&
383                                 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
384                         acctflag = VM_NORESERVE;
385                 file = shmem_file_setup(name, size, acctflag);
386         }
387         error = PTR_ERR(file);
388         if (IS_ERR(file))
389                 goto no_file;
390
391         id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
392         if (id < 0) {
393                 error = id;
394                 goto no_id;
395         }
396
397         shp->shm_cprid = task_tgid_vnr(current);
398         shp->shm_lprid = 0;
399         shp->shm_atim = shp->shm_dtim = 0;
400         shp->shm_ctim = get_seconds();
401         shp->shm_segsz = size;
402         shp->shm_nattch = 0;
403         shp->shm_file = file;
404         /*
405          * shmid gets reported as "inode#" in /proc/pid/maps.
406          * proc-ps tools use this. Changing this will break them.
407          */
408         file->f_dentry->d_inode->i_ino = shp->shm_perm.id;
409
410         ns->shm_tot += numpages;
411         error = shp->shm_perm.id;
412         shm_unlock(shp);
413         return error;
414
415 no_id:
416         if (is_file_hugepages(file) && shp->mlock_user)
417                 user_shm_unlock(size, shp->mlock_user);
418         fput(file);
419 no_file:
420         security_shm_free(shp);
421         ipc_rcu_putref(shp);
422         return error;
423 }
424
425 /*
426  * Called with shm_ids.rw_mutex and ipcp locked.
427  */
428 static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)
429 {
430         struct shmid_kernel *shp;
431
432         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
433         return security_shm_associate(shp, shmflg);
434 }
435
436 /*
437  * Called with shm_ids.rw_mutex and ipcp locked.
438  */
439 static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
440                                 struct ipc_params *params)
441 {
442         struct shmid_kernel *shp;
443
444         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
445         if (shp->shm_segsz < params->u.size)
446                 return -EINVAL;
447
448         return 0;
449 }
450
451 SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg)
452 {
453         struct ipc_namespace *ns;
454         struct ipc_ops shm_ops;
455         struct ipc_params shm_params;
456
457         ns = current->nsproxy->ipc_ns;
458
459         shm_ops.getnew = newseg;
460         shm_ops.associate = shm_security;
461         shm_ops.more_checks = shm_more_checks;
462
463         shm_params.key = key;
464         shm_params.flg = shmflg;
465         shm_params.u.size = size;
466
467         return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
468 }
469
470 static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
471 {
472         switch(version) {
473         case IPC_64:
474                 return copy_to_user(buf, in, sizeof(*in));
475         case IPC_OLD:
476             {
477                 struct shmid_ds out;
478
479                 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
480                 out.shm_segsz   = in->shm_segsz;
481                 out.shm_atime   = in->shm_atime;
482                 out.shm_dtime   = in->shm_dtime;
483                 out.shm_ctime   = in->shm_ctime;
484                 out.shm_cpid    = in->shm_cpid;
485                 out.shm_lpid    = in->shm_lpid;
486                 out.shm_nattch  = in->shm_nattch;
487
488                 return copy_to_user(buf, &out, sizeof(out));
489             }
490         default:
491                 return -EINVAL;
492         }
493 }
494
495 static inline unsigned long
496 copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version)
497 {
498         switch(version) {
499         case IPC_64:
500                 if (copy_from_user(out, buf, sizeof(*out)))
501                         return -EFAULT;
502                 return 0;
503         case IPC_OLD:
504             {
505                 struct shmid_ds tbuf_old;
506
507                 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
508                         return -EFAULT;
509
510                 out->shm_perm.uid       = tbuf_old.shm_perm.uid;
511                 out->shm_perm.gid       = tbuf_old.shm_perm.gid;
512                 out->shm_perm.mode      = tbuf_old.shm_perm.mode;
513
514                 return 0;
515             }
516         default:
517                 return -EINVAL;
518         }
519 }
520
521 static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
522 {
523         switch(version) {
524         case IPC_64:
525                 return copy_to_user(buf, in, sizeof(*in));
526         case IPC_OLD:
527             {
528                 struct shminfo out;
529
530                 if(in->shmmax > INT_MAX)
531                         out.shmmax = INT_MAX;
532                 else
533                         out.shmmax = (int)in->shmmax;
534
535                 out.shmmin      = in->shmmin;
536                 out.shmmni      = in->shmmni;
537                 out.shmseg      = in->shmseg;
538                 out.shmall      = in->shmall; 
539
540                 return copy_to_user(buf, &out, sizeof(out));
541             }
542         default:
543                 return -EINVAL;
544         }
545 }
546
547 /*
548  * Called with shm_ids.rw_mutex held as a reader
549  */
550 static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
551                 unsigned long *swp)
552 {
553         int next_id;
554         int total, in_use;
555
556         *rss = 0;
557         *swp = 0;
558
559         in_use = shm_ids(ns).in_use;
560
561         for (total = 0, next_id = 0; total < in_use; next_id++) {
562                 struct kern_ipc_perm *ipc;
563                 struct shmid_kernel *shp;
564                 struct inode *inode;
565
566                 ipc = idr_find(&shm_ids(ns).ipcs_idr, next_id);
567                 if (ipc == NULL)
568                         continue;
569                 shp = container_of(ipc, struct shmid_kernel, shm_perm);
570
571                 inode = shp->shm_file->f_path.dentry->d_inode;
572
573                 if (is_file_hugepages(shp->shm_file)) {
574                         struct address_space *mapping = inode->i_mapping;
575                         struct hstate *h = hstate_file(shp->shm_file);
576                         *rss += pages_per_huge_page(h) * mapping->nrpages;
577                 } else {
578 #ifdef CONFIG_SHMEM
579                         struct shmem_inode_info *info = SHMEM_I(inode);
580                         spin_lock(&info->lock);
581                         *rss += inode->i_mapping->nrpages;
582                         *swp += info->swapped;
583                         spin_unlock(&info->lock);
584 #else
585                         *rss += inode->i_mapping->nrpages;
586 #endif
587                 }
588
589                 total++;
590         }
591 }
592
593 /*
594  * This function handles some shmctl commands which require the rw_mutex
595  * to be held in write mode.
596  * NOTE: no locks must be held, the rw_mutex is taken inside this function.
597  */
598 static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
599                        struct shmid_ds __user *buf, int version)
600 {
601         struct kern_ipc_perm *ipcp;
602         struct shmid64_ds shmid64;
603         struct shmid_kernel *shp;
604         int err;
605
606         if (cmd == IPC_SET) {
607                 if (copy_shmid_from_user(&shmid64, buf, version))
608                         return -EFAULT;
609         }
610
611         ipcp = ipcctl_pre_down(&shm_ids(ns), shmid, cmd, &shmid64.shm_perm, 0);
612         if (IS_ERR(ipcp))
613                 return PTR_ERR(ipcp);
614
615         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
616
617         err = security_shm_shmctl(shp, cmd);
618         if (err)
619                 goto out_unlock;
620         switch (cmd) {
621         case IPC_RMID:
622                 do_shm_rmid(ns, ipcp);
623                 goto out_up;
624         case IPC_SET:
625                 ipc_update_perm(&shmid64.shm_perm, ipcp);
626                 shp->shm_ctim = get_seconds();
627                 break;
628         default:
629                 err = -EINVAL;
630         }
631 out_unlock:
632         shm_unlock(shp);
633 out_up:
634         up_write(&shm_ids(ns).rw_mutex);
635         return err;
636 }
637
638 SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
639 {
640         struct shmid_kernel *shp;
641         int err, version;
642         struct ipc_namespace *ns;
643
644         if (cmd < 0 || shmid < 0) {
645                 err = -EINVAL;
646                 goto out;
647         }
648
649         version = ipc_parse_version(&cmd);
650         ns = current->nsproxy->ipc_ns;
651
652         switch (cmd) { /* replace with proc interface ? */
653         case IPC_INFO:
654         {
655                 struct shminfo64 shminfo;
656
657                 err = security_shm_shmctl(NULL, cmd);
658                 if (err)
659                         return err;
660
661                 memset(&shminfo, 0, sizeof(shminfo));
662                 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
663                 shminfo.shmmax = ns->shm_ctlmax;
664                 shminfo.shmall = ns->shm_ctlall;
665
666                 shminfo.shmmin = SHMMIN;
667                 if(copy_shminfo_to_user (buf, &shminfo, version))
668                         return -EFAULT;
669
670                 down_read(&shm_ids(ns).rw_mutex);
671                 err = ipc_get_maxid(&shm_ids(ns));
672                 up_read(&shm_ids(ns).rw_mutex);
673
674                 if(err<0)
675                         err = 0;
676                 goto out;
677         }
678         case SHM_INFO:
679         {
680                 struct shm_info shm_info;
681
682                 err = security_shm_shmctl(NULL, cmd);
683                 if (err)
684                         return err;
685
686                 memset(&shm_info, 0, sizeof(shm_info));
687                 down_read(&shm_ids(ns).rw_mutex);
688                 shm_info.used_ids = shm_ids(ns).in_use;
689                 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
690                 shm_info.shm_tot = ns->shm_tot;
691                 shm_info.swap_attempts = 0;
692                 shm_info.swap_successes = 0;
693                 err = ipc_get_maxid(&shm_ids(ns));
694                 up_read(&shm_ids(ns).rw_mutex);
695                 if (copy_to_user(buf, &shm_info, sizeof(shm_info))) {
696                         err = -EFAULT;
697                         goto out;
698                 }
699
700                 err = err < 0 ? 0 : err;
701                 goto out;
702         }
703         case SHM_STAT:
704         case IPC_STAT:
705         {
706                 struct shmid64_ds tbuf;
707                 int result;
708
709                 if (cmd == SHM_STAT) {
710                         shp = shm_lock(ns, shmid);
711                         if (IS_ERR(shp)) {
712                                 err = PTR_ERR(shp);
713                                 goto out;
714                         }
715                         result = shp->shm_perm.id;
716                 } else {
717                         shp = shm_lock_check(ns, shmid);
718                         if (IS_ERR(shp)) {
719                                 err = PTR_ERR(shp);
720                                 goto out;
721                         }
722                         result = 0;
723                 }
724                 err = -EACCES;
725                 if (ipcperms (&shp->shm_perm, S_IRUGO))
726                         goto out_unlock;
727                 err = security_shm_shmctl(shp, cmd);
728                 if (err)
729                         goto out_unlock;
730                 memset(&tbuf, 0, sizeof(tbuf));
731                 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
732                 tbuf.shm_segsz  = shp->shm_segsz;
733                 tbuf.shm_atime  = shp->shm_atim;
734                 tbuf.shm_dtime  = shp->shm_dtim;
735                 tbuf.shm_ctime  = shp->shm_ctim;
736                 tbuf.shm_cpid   = shp->shm_cprid;
737                 tbuf.shm_lpid   = shp->shm_lprid;
738                 tbuf.shm_nattch = shp->shm_nattch;
739                 shm_unlock(shp);
740                 if(copy_shmid_to_user (buf, &tbuf, version))
741                         err = -EFAULT;
742                 else
743                         err = result;
744                 goto out;
745         }
746         case SHM_LOCK:
747         case SHM_UNLOCK:
748         {
749                 struct file *uninitialized_var(shm_file);
750
751                 lru_add_drain_all();  /* drain pagevecs to lru lists */
752
753                 shp = shm_lock_check(ns, shmid);
754                 if (IS_ERR(shp)) {
755                         err = PTR_ERR(shp);
756                         goto out;
757                 }
758
759                 audit_ipc_obj(&(shp->shm_perm));
760
761                 if (!capable(CAP_IPC_LOCK)) {
762                         uid_t euid = current_euid();
763                         err = -EPERM;
764                         if (euid != shp->shm_perm.uid &&
765                             euid != shp->shm_perm.cuid)
766                                 goto out_unlock;
767                         if (cmd == SHM_LOCK &&
768                             !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur)
769                                 goto out_unlock;
770                 }
771
772                 err = security_shm_shmctl(shp, cmd);
773                 if (err)
774                         goto out_unlock;
775                 
776                 if(cmd==SHM_LOCK) {
777                         struct user_struct *user = current_user();
778                         if (!is_file_hugepages(shp->shm_file)) {
779                                 err = shmem_lock(shp->shm_file, 1, user);
780                                 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)){
781                                         shp->shm_perm.mode |= SHM_LOCKED;
782                                         shp->mlock_user = user;
783                                 }
784                         }
785                 } else if (!is_file_hugepages(shp->shm_file)) {
786                         shmem_lock(shp->shm_file, 0, shp->mlock_user);
787                         shp->shm_perm.mode &= ~SHM_LOCKED;
788                         shp->mlock_user = NULL;
789                 }
790                 shm_unlock(shp);
791                 goto out;
792         }
793         case IPC_RMID:
794         case IPC_SET:
795                 err = shmctl_down(ns, shmid, cmd, buf, version);
796                 return err;
797         default:
798                 return -EINVAL;
799         }
800
801 out_unlock:
802         shm_unlock(shp);
803 out:
804         return err;
805 }
806
807 /*
808  * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
809  *
810  * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
811  * "raddr" thing points to kernel space, and there has to be a wrapper around
812  * this.
813  */
814 long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
815 {
816         struct shmid_kernel *shp;
817         unsigned long addr;
818         unsigned long size;
819         struct file * file;
820         int    err;
821         unsigned long flags;
822         unsigned long prot;
823         int acc_mode;
824         unsigned long user_addr;
825         struct ipc_namespace *ns;
826         struct shm_file_data *sfd;
827         struct path path;
828         fmode_t f_mode;
829
830         err = -EINVAL;
831         if (shmid < 0)
832                 goto out;
833         else if ((addr = (ulong)shmaddr)) {
834                 if (addr & (SHMLBA-1)) {
835                         if (shmflg & SHM_RND)
836                                 addr &= ~(SHMLBA-1);       /* round down */
837                         else
838 #ifndef __ARCH_FORCE_SHMLBA
839                                 if (addr & ~PAGE_MASK)
840 #endif
841                                         goto out;
842                 }
843                 flags = MAP_SHARED | MAP_FIXED;
844         } else {
845                 if ((shmflg & SHM_REMAP))
846                         goto out;
847
848                 flags = MAP_SHARED;
849         }
850
851         if (shmflg & SHM_RDONLY) {
852                 prot = PROT_READ;
853                 acc_mode = S_IRUGO;
854                 f_mode = FMODE_READ;
855         } else {
856                 prot = PROT_READ | PROT_WRITE;
857                 acc_mode = S_IRUGO | S_IWUGO;
858                 f_mode = FMODE_READ | FMODE_WRITE;
859         }
860         if (shmflg & SHM_EXEC) {
861                 prot |= PROT_EXEC;
862                 acc_mode |= S_IXUGO;
863         }
864
865         /*
866          * We cannot rely on the fs check since SYSV IPC does have an
867          * additional creator id...
868          */
869         ns = current->nsproxy->ipc_ns;
870         shp = shm_lock_check(ns, shmid);
871         if (IS_ERR(shp)) {
872                 err = PTR_ERR(shp);
873                 goto out;
874         }
875
876         err = -EACCES;
877         if (ipcperms(&shp->shm_perm, acc_mode))
878                 goto out_unlock;
879
880         err = security_shm_shmat(shp, shmaddr, shmflg);
881         if (err)
882                 goto out_unlock;
883
884         path = shp->shm_file->f_path;
885         path_get(&path);
886         shp->shm_nattch++;
887         size = i_size_read(path.dentry->d_inode);
888         shm_unlock(shp);
889
890         err = -ENOMEM;
891         sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
892         if (!sfd)
893                 goto out_put_dentry;
894
895         file = alloc_file(&path, f_mode,
896                           is_file_hugepages(shp->shm_file) ?
897                                 &shm_file_operations_huge :
898                                 &shm_file_operations);
899         if (!file)
900                 goto out_free;
901
902         file->private_data = sfd;
903         file->f_mapping = shp->shm_file->f_mapping;
904         sfd->id = shp->shm_perm.id;
905         sfd->ns = get_ipc_ns(ns);
906         sfd->file = shp->shm_file;
907         sfd->vm_ops = NULL;
908
909         down_write(&current->mm->mmap_sem);
910         if (addr && !(shmflg & SHM_REMAP)) {
911                 err = -EINVAL;
912                 if (find_vma_intersection(current->mm, addr, addr + size))
913                         goto invalid;
914                 /*
915                  * If shm segment goes below stack, make sure there is some
916                  * space left for the stack to grow (at least 4 pages).
917                  */
918                 if (addr < current->mm->start_stack &&
919                     addr > current->mm->start_stack - size - PAGE_SIZE * 5)
920                         goto invalid;
921         }
922                 
923         user_addr = do_mmap (file, addr, size, prot, flags, 0);
924         *raddr = user_addr;
925         err = 0;
926         if (IS_ERR_VALUE(user_addr))
927                 err = (long)user_addr;
928 invalid:
929         up_write(&current->mm->mmap_sem);
930
931         fput(file);
932
933 out_nattch:
934         down_write(&shm_ids(ns).rw_mutex);
935         shp = shm_lock(ns, shmid);
936         BUG_ON(IS_ERR(shp));
937         shp->shm_nattch--;
938         if(shp->shm_nattch == 0 &&
939            shp->shm_perm.mode & SHM_DEST)
940                 shm_destroy(ns, shp);
941         else
942                 shm_unlock(shp);
943         up_write(&shm_ids(ns).rw_mutex);
944
945 out:
946         return err;
947
948 out_unlock:
949         shm_unlock(shp);
950         goto out;
951
952 out_free:
953         kfree(sfd);
954 out_put_dentry:
955         path_put(&path);
956         goto out_nattch;
957 }
958
959 SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg)
960 {
961         unsigned long ret;
962         long err;
963
964         err = do_shmat(shmid, shmaddr, shmflg, &ret);
965         if (err)
966                 return err;
967         force_successful_syscall_return();
968         return (long)ret;
969 }
970
971 /*
972  * detach and kill segment if marked destroyed.
973  * The work is done in shm_close.
974  */
975 SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
976 {
977         struct mm_struct *mm = current->mm;
978         struct vm_area_struct *vma;
979         unsigned long addr = (unsigned long)shmaddr;
980         int retval = -EINVAL;
981 #ifdef CONFIG_MMU
982         loff_t size = 0;
983         struct vm_area_struct *next;
984 #endif
985
986         if (addr & ~PAGE_MASK)
987                 return retval;
988
989         down_write(&mm->mmap_sem);
990
991         /*
992          * This function tries to be smart and unmap shm segments that
993          * were modified by partial mlock or munmap calls:
994          * - It first determines the size of the shm segment that should be
995          *   unmapped: It searches for a vma that is backed by shm and that
996          *   started at address shmaddr. It records it's size and then unmaps
997          *   it.
998          * - Then it unmaps all shm vmas that started at shmaddr and that
999          *   are within the initially determined size.
1000          * Errors from do_munmap are ignored: the function only fails if
1001          * it's called with invalid parameters or if it's called to unmap
1002          * a part of a vma. Both calls in this function are for full vmas,
1003          * the parameters are directly copied from the vma itself and always
1004          * valid - therefore do_munmap cannot fail. (famous last words?)
1005          */
1006         /*
1007          * If it had been mremap()'d, the starting address would not
1008          * match the usual checks anyway. So assume all vma's are
1009          * above the starting address given.
1010          */
1011         vma = find_vma(mm, addr);
1012
1013 #ifdef CONFIG_MMU
1014         while (vma) {
1015                 next = vma->vm_next;
1016
1017                 /*
1018                  * Check if the starting address would match, i.e. it's
1019                  * a fragment created by mprotect() and/or munmap(), or it
1020                  * otherwise it starts at this address with no hassles.
1021                  */
1022                 if ((vma->vm_ops == &shm_vm_ops) &&
1023                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1024
1025
1026                         size = vma->vm_file->f_path.dentry->d_inode->i_size;
1027                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1028                         /*
1029                          * We discovered the size of the shm segment, so
1030                          * break out of here and fall through to the next
1031                          * loop that uses the size information to stop
1032                          * searching for matching vma's.
1033                          */
1034                         retval = 0;
1035                         vma = next;
1036                         break;
1037                 }
1038                 vma = next;
1039         }
1040
1041         /*
1042          * We need look no further than the maximum address a fragment
1043          * could possibly have landed at. Also cast things to loff_t to
1044          * prevent overflows and make comparisions vs. equal-width types.
1045          */
1046         size = PAGE_ALIGN(size);
1047         while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1048                 next = vma->vm_next;
1049
1050                 /* finding a matching vma now does not alter retval */
1051                 if ((vma->vm_ops == &shm_vm_ops) &&
1052                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1053
1054                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1055                 vma = next;
1056         }
1057
1058 #else /* CONFIG_MMU */
1059         /* under NOMMU conditions, the exact address to be destroyed must be
1060          * given */
1061         retval = -EINVAL;
1062         if (vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) {
1063                 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1064                 retval = 0;
1065         }
1066
1067 #endif
1068
1069         up_write(&mm->mmap_sem);
1070         return retval;
1071 }
1072
1073 #ifdef CONFIG_PROC_FS
1074 static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1075 {
1076         struct shmid_kernel *shp = it;
1077
1078 #if BITS_PER_LONG <= 32
1079 #define SIZE_SPEC "%10lu"
1080 #else
1081 #define SIZE_SPEC "%21lu"
1082 #endif
1083
1084         return seq_printf(s,
1085                           "%10d %10d  %4o " SIZE_SPEC " %5u %5u  "
1086                           "%5lu %5u %5u %5u %5u %10lu %10lu %10lu\n",
1087                           shp->shm_perm.key,
1088                           shp->shm_perm.id,
1089                           shp->shm_perm.mode,
1090                           shp->shm_segsz,
1091                           shp->shm_cprid,
1092                           shp->shm_lprid,
1093                           shp->shm_nattch,
1094                           shp->shm_perm.uid,
1095                           shp->shm_perm.gid,
1096                           shp->shm_perm.cuid,
1097                           shp->shm_perm.cgid,
1098                           shp->shm_atim,
1099                           shp->shm_dtim,
1100                           shp->shm_ctim);
1101 }
1102 #endif