d20cc25c5bdfb0cc7143584150f394f1f4b49901
[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/mutex.h>
39 #include <linux/nsproxy.h>
40 #include <linux/mount.h>
41
42 #include <asm/uaccess.h>
43
44 #include "util.h"
45
46 struct shm_file_data {
47         int id;
48         struct ipc_namespace *ns;
49         struct file *file;
50         const struct vm_operations_struct *vm_ops;
51 };
52
53 #define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data))
54
55 static const struct file_operations shm_file_operations;
56 static struct vm_operations_struct shm_vm_ops;
57
58 static struct ipc_ids init_shm_ids;
59
60 #define shm_ids(ns)     (*((ns)->ids[IPC_SHM_IDS]))
61
62 #define shm_lock(ns, id)                \
63         ((struct shmid_kernel*)ipc_lock(&shm_ids(ns),id))
64 #define shm_unlock(shp)                 \
65         ipc_unlock(&(shp)->shm_perm)
66 #define shm_get(ns, id)                 \
67         ((struct shmid_kernel*)ipc_get(&shm_ids(ns),id))
68 #define shm_buildid(ns, id, seq)        \
69         ipc_buildid(&shm_ids(ns), id, seq)
70
71 static int newseg(struct ipc_namespace *, struct ipc_params *);
72 static void shm_open(struct vm_area_struct *vma);
73 static void shm_close(struct vm_area_struct *vma);
74 static void shm_destroy (struct ipc_namespace *ns, struct shmid_kernel *shp);
75 #ifdef CONFIG_PROC_FS
76 static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
77 #endif
78
79 static void __shm_init_ns(struct ipc_namespace *ns, struct ipc_ids *ids)
80 {
81         ns->ids[IPC_SHM_IDS] = ids;
82         ns->shm_ctlmax = SHMMAX;
83         ns->shm_ctlall = SHMALL;
84         ns->shm_ctlmni = SHMMNI;
85         ns->shm_tot = 0;
86         ipc_init_ids(ids);
87 }
88
89 static void do_shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *shp)
90 {
91         if (shp->shm_nattch){
92                 shp->shm_perm.mode |= SHM_DEST;
93                 /* Do not find it any more */
94                 shp->shm_perm.key = IPC_PRIVATE;
95                 shm_unlock(shp);
96         } else
97                 shm_destroy(ns, shp);
98 }
99
100 int shm_init_ns(struct ipc_namespace *ns)
101 {
102         struct ipc_ids *ids;
103
104         ids = kmalloc(sizeof(struct ipc_ids), GFP_KERNEL);
105         if (ids == NULL)
106                 return -ENOMEM;
107
108         __shm_init_ns(ns, ids);
109         return 0;
110 }
111
112 void shm_exit_ns(struct ipc_namespace *ns)
113 {
114         struct shmid_kernel *shp;
115         int next_id;
116         int total, in_use;
117
118         mutex_lock(&shm_ids(ns).mutex);
119
120         in_use = shm_ids(ns).in_use;
121
122         for (total = 0, next_id = 0; total < in_use; next_id++) {
123                 shp = idr_find(&shm_ids(ns).ipcs_idr, next_id);
124                 if (shp == NULL)
125                         continue;
126                 ipc_lock_by_ptr(&shp->shm_perm);
127                 do_shm_rmid(ns, shp);
128                 total++;
129         }
130         mutex_unlock(&shm_ids(ns).mutex);
131
132         kfree(ns->ids[IPC_SHM_IDS]);
133         ns->ids[IPC_SHM_IDS] = NULL;
134 }
135
136 void __init shm_init (void)
137 {
138         __shm_init_ns(&init_ipc_ns, &init_shm_ids);
139         ipc_init_proc_interface("sysvipc/shm",
140                                 "       key      shmid perms       size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime\n",
141                                 IPC_SHM_IDS, sysvipc_shm_proc_show);
142 }
143
144 static inline int shm_checkid(struct ipc_namespace *ns,
145                 struct shmid_kernel *s, int id)
146 {
147         if (ipc_checkid(&shm_ids(ns), &s->shm_perm, id))
148                 return -EIDRM;
149         return 0;
150 }
151
152 static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
153 {
154         ipc_rmid(&shm_ids(ns), &s->shm_perm);
155 }
156
157 static inline int shm_addid(struct ipc_namespace *ns, struct shmid_kernel *shp)
158 {
159         return ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
160 }
161
162
163
164 /* This is called by fork, once for every shm attach. */
165 static void shm_open(struct vm_area_struct *vma)
166 {
167         struct file *file = vma->vm_file;
168         struct shm_file_data *sfd = shm_file_data(file);
169         struct shmid_kernel *shp;
170
171         shp = shm_lock(sfd->ns, sfd->id);
172         BUG_ON(!shp);
173         shp->shm_atim = get_seconds();
174         shp->shm_lprid = task_tgid_vnr(current);
175         shp->shm_nattch++;
176         shm_unlock(shp);
177 }
178
179 /*
180  * shm_destroy - free the struct shmid_kernel
181  *
182  * @shp: struct to free
183  *
184  * It has to be called with shp and shm_ids.mutex locked,
185  * but returns with shp unlocked and freed.
186  */
187 static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
188 {
189         ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
190         shm_rmid(ns, shp);
191         shm_unlock(shp);
192         if (!is_file_hugepages(shp->shm_file))
193                 shmem_lock(shp->shm_file, 0, shp->mlock_user);
194         else
195                 user_shm_unlock(shp->shm_file->f_path.dentry->d_inode->i_size,
196                                                 shp->mlock_user);
197         fput (shp->shm_file);
198         security_shm_free(shp);
199         ipc_rcu_putref(shp);
200 }
201
202 /*
203  * remove the attach descriptor vma.
204  * free memory for segment if it is marked destroyed.
205  * The descriptor has already been removed from the current->mm->mmap list
206  * and will later be kfree()d.
207  */
208 static void shm_close(struct vm_area_struct *vma)
209 {
210         struct file * file = vma->vm_file;
211         struct shm_file_data *sfd = shm_file_data(file);
212         struct shmid_kernel *shp;
213         struct ipc_namespace *ns = sfd->ns;
214
215         mutex_lock(&shm_ids(ns).mutex);
216         /* remove from the list of attaches of the shm segment */
217         shp = shm_lock(ns, sfd->id);
218         BUG_ON(!shp);
219         shp->shm_lprid = task_tgid_vnr(current);
220         shp->shm_dtim = get_seconds();
221         shp->shm_nattch--;
222         if(shp->shm_nattch == 0 &&
223            shp->shm_perm.mode & SHM_DEST)
224                 shm_destroy(ns, shp);
225         else
226                 shm_unlock(shp);
227         mutex_unlock(&shm_ids(ns).mutex);
228 }
229
230 static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
231 {
232         struct file *file = vma->vm_file;
233         struct shm_file_data *sfd = shm_file_data(file);
234
235         return sfd->vm_ops->fault(vma, vmf);
236 }
237
238 #ifdef CONFIG_NUMA
239 static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
240 {
241         struct file *file = vma->vm_file;
242         struct shm_file_data *sfd = shm_file_data(file);
243         int err = 0;
244         if (sfd->vm_ops->set_policy)
245                 err = sfd->vm_ops->set_policy(vma, new);
246         return err;
247 }
248
249 static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
250                                         unsigned long addr)
251 {
252         struct file *file = vma->vm_file;
253         struct shm_file_data *sfd = shm_file_data(file);
254         struct mempolicy *pol = NULL;
255
256         if (sfd->vm_ops->get_policy)
257                 pol = sfd->vm_ops->get_policy(vma, addr);
258         else if (vma->vm_policy)
259                 pol = vma->vm_policy;
260         else
261                 pol = current->mempolicy;
262         return pol;
263 }
264 #endif
265
266 static int shm_mmap(struct file * file, struct vm_area_struct * vma)
267 {
268         struct shm_file_data *sfd = shm_file_data(file);
269         int ret;
270
271         ret = sfd->file->f_op->mmap(sfd->file, vma);
272         if (ret != 0)
273                 return ret;
274         sfd->vm_ops = vma->vm_ops;
275 #ifdef CONFIG_MMU
276         BUG_ON(!sfd->vm_ops->fault);
277 #endif
278         vma->vm_ops = &shm_vm_ops;
279         shm_open(vma);
280
281         return ret;
282 }
283
284 static int shm_release(struct inode *ino, struct file *file)
285 {
286         struct shm_file_data *sfd = shm_file_data(file);
287
288         put_ipc_ns(sfd->ns);
289         shm_file_data(file) = NULL;
290         kfree(sfd);
291         return 0;
292 }
293
294 static int shm_fsync(struct file *file, struct dentry *dentry, int datasync)
295 {
296         int (*fsync) (struct file *, struct dentry *, int datasync);
297         struct shm_file_data *sfd = shm_file_data(file);
298         int ret = -EINVAL;
299
300         fsync = sfd->file->f_op->fsync;
301         if (fsync)
302                 ret = fsync(sfd->file, sfd->file->f_path.dentry, datasync);
303         return ret;
304 }
305
306 static unsigned long shm_get_unmapped_area(struct file *file,
307         unsigned long addr, unsigned long len, unsigned long pgoff,
308         unsigned long flags)
309 {
310         struct shm_file_data *sfd = shm_file_data(file);
311         return get_unmapped_area(sfd->file, addr, len, pgoff, flags);
312 }
313
314 int is_file_shm_hugepages(struct file *file)
315 {
316         int ret = 0;
317
318         if (file->f_op == &shm_file_operations) {
319                 struct shm_file_data *sfd;
320                 sfd = shm_file_data(file);
321                 ret = is_file_hugepages(sfd->file);
322         }
323         return ret;
324 }
325
326 static const struct file_operations shm_file_operations = {
327         .mmap           = shm_mmap,
328         .fsync          = shm_fsync,
329         .release        = shm_release,
330         .get_unmapped_area      = shm_get_unmapped_area,
331 };
332
333 static struct vm_operations_struct shm_vm_ops = {
334         .open   = shm_open,     /* callback for a new vm-area open */
335         .close  = shm_close,    /* callback for when the vm-area is released */
336         .fault  = shm_fault,
337 #if defined(CONFIG_NUMA)
338         .set_policy = shm_set_policy,
339         .get_policy = shm_get_policy,
340 #endif
341 };
342
343 static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
344 {
345         key_t key = params->key;
346         int shmflg = params->flg;
347         size_t size = params->u.size;
348         int error;
349         struct shmid_kernel *shp;
350         int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
351         struct file * file;
352         char name[13];
353         int id;
354
355         if (size < SHMMIN || size > ns->shm_ctlmax)
356                 return -EINVAL;
357
358         if (ns->shm_tot + numpages > ns->shm_ctlall)
359                 return -ENOSPC;
360
361         shp = ipc_rcu_alloc(sizeof(*shp));
362         if (!shp)
363                 return -ENOMEM;
364
365         shp->shm_perm.key = key;
366         shp->shm_perm.mode = (shmflg & S_IRWXUGO);
367         shp->mlock_user = NULL;
368
369         shp->shm_perm.security = NULL;
370         error = security_shm_alloc(shp);
371         if (error) {
372                 ipc_rcu_putref(shp);
373                 return error;
374         }
375
376         sprintf (name, "SYSV%08x", key);
377         if (shmflg & SHM_HUGETLB) {
378                 /* hugetlb_file_setup takes care of mlock user accounting */
379                 file = hugetlb_file_setup(name, size);
380                 shp->mlock_user = current->user;
381         } else {
382                 int acctflag = VM_ACCOUNT;
383                 /*
384                  * Do not allow no accounting for OVERCOMMIT_NEVER, even
385                  * if it's asked for.
386                  */
387                 if  ((shmflg & SHM_NORESERVE) &&
388                                 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
389                         acctflag = 0;
390                 file = shmem_file_setup(name, size, acctflag);
391         }
392         error = PTR_ERR(file);
393         if (IS_ERR(file))
394                 goto no_file;
395
396         error = -ENOSPC;
397         id = shm_addid(ns, shp);
398         if(id == -1) 
399                 goto no_id;
400
401         shp->shm_cprid = task_tgid_vnr(current);
402         shp->shm_lprid = 0;
403         shp->shm_atim = shp->shm_dtim = 0;
404         shp->shm_ctim = get_seconds();
405         shp->shm_segsz = size;
406         shp->shm_nattch = 0;
407         shp->shm_perm.id = shm_buildid(ns, id, shp->shm_perm.seq);
408         shp->shm_file = file;
409         /*
410          * shmid gets reported as "inode#" in /proc/pid/maps.
411          * proc-ps tools use this. Changing this will break them.
412          */
413         file->f_dentry->d_inode->i_ino = shp->shm_perm.id;
414
415         ns->shm_tot += numpages;
416         error = shp->shm_perm.id;
417         shm_unlock(shp);
418         return error;
419
420 no_id:
421         fput(file);
422 no_file:
423         security_shm_free(shp);
424         ipc_rcu_putref(shp);
425         return error;
426 }
427
428 static inline int shm_security(void *shp, int shmflg)
429 {
430         return security_shm_associate((struct shmid_kernel *) shp, shmflg);
431 }
432
433 static inline int shm_more_checks(void *shp, struct ipc_params *params)
434 {
435         if (((struct shmid_kernel *)shp)->shm_segsz < params->u.size)
436                 return -EINVAL;
437
438         return 0;
439 }
440
441 asmlinkage long sys_shmget (key_t key, size_t size, int shmflg)
442 {
443         struct ipc_namespace *ns;
444         struct ipc_ops shm_ops;
445         struct ipc_params shm_params;
446
447         ns = current->nsproxy->ipc_ns;
448
449         shm_ops.getnew = newseg;
450         shm_ops.associate = shm_security;
451         shm_ops.more_checks = shm_more_checks;
452
453         shm_params.key = key;
454         shm_params.flg = shmflg;
455         shm_params.u.size = size;
456
457         return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
458 }
459
460 static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
461 {
462         switch(version) {
463         case IPC_64:
464                 return copy_to_user(buf, in, sizeof(*in));
465         case IPC_OLD:
466             {
467                 struct shmid_ds out;
468
469                 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
470                 out.shm_segsz   = in->shm_segsz;
471                 out.shm_atime   = in->shm_atime;
472                 out.shm_dtime   = in->shm_dtime;
473                 out.shm_ctime   = in->shm_ctime;
474                 out.shm_cpid    = in->shm_cpid;
475                 out.shm_lpid    = in->shm_lpid;
476                 out.shm_nattch  = in->shm_nattch;
477
478                 return copy_to_user(buf, &out, sizeof(out));
479             }
480         default:
481                 return -EINVAL;
482         }
483 }
484
485 struct shm_setbuf {
486         uid_t   uid;
487         gid_t   gid;
488         mode_t  mode;
489 };      
490
491 static inline unsigned long copy_shmid_from_user(struct shm_setbuf *out, void __user *buf, int version)
492 {
493         switch(version) {
494         case IPC_64:
495             {
496                 struct shmid64_ds tbuf;
497
498                 if (copy_from_user(&tbuf, buf, sizeof(tbuf)))
499                         return -EFAULT;
500
501                 out->uid        = tbuf.shm_perm.uid;
502                 out->gid        = tbuf.shm_perm.gid;
503                 out->mode       = tbuf.shm_perm.mode;
504
505                 return 0;
506             }
507         case IPC_OLD:
508             {
509                 struct shmid_ds tbuf_old;
510
511                 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
512                         return -EFAULT;
513
514                 out->uid        = tbuf_old.shm_perm.uid;
515                 out->gid        = tbuf_old.shm_perm.gid;
516                 out->mode       = tbuf_old.shm_perm.mode;
517
518                 return 0;
519             }
520         default:
521                 return -EINVAL;
522         }
523 }
524
525 static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
526 {
527         switch(version) {
528         case IPC_64:
529                 return copy_to_user(buf, in, sizeof(*in));
530         case IPC_OLD:
531             {
532                 struct shminfo out;
533
534                 if(in->shmmax > INT_MAX)
535                         out.shmmax = INT_MAX;
536                 else
537                         out.shmmax = (int)in->shmmax;
538
539                 out.shmmin      = in->shmmin;
540                 out.shmmni      = in->shmmni;
541                 out.shmseg      = in->shmseg;
542                 out.shmall      = in->shmall; 
543
544                 return copy_to_user(buf, &out, sizeof(out));
545             }
546         default:
547                 return -EINVAL;
548         }
549 }
550
551 static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
552                 unsigned long *swp)
553 {
554         int next_id;
555         int total, in_use;
556
557         *rss = 0;
558         *swp = 0;
559
560         in_use = shm_ids(ns).in_use;
561
562         for (total = 0, next_id = 0; total < in_use; next_id++) {
563                 struct shmid_kernel *shp;
564                 struct inode *inode;
565
566                 shp = shm_get(ns, next_id);
567                 if (shp == NULL)
568                         continue;
569
570                 inode = shp->shm_file->f_path.dentry->d_inode;
571
572                 if (is_file_hugepages(shp->shm_file)) {
573                         struct address_space *mapping = inode->i_mapping;
574                         *rss += (HPAGE_SIZE/PAGE_SIZE)*mapping->nrpages;
575                 } else {
576                         struct shmem_inode_info *info = SHMEM_I(inode);
577                         spin_lock(&info->lock);
578                         *rss += inode->i_mapping->nrpages;
579                         *swp += info->swapped;
580                         spin_unlock(&info->lock);
581                 }
582
583                 total++;
584         }
585 }
586
587 asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
588 {
589         struct shm_setbuf setbuf;
590         struct shmid_kernel *shp;
591         int err, version;
592         struct ipc_namespace *ns;
593
594         if (cmd < 0 || shmid < 0) {
595                 err = -EINVAL;
596                 goto out;
597         }
598
599         version = ipc_parse_version(&cmd);
600         ns = current->nsproxy->ipc_ns;
601
602         switch (cmd) { /* replace with proc interface ? */
603         case IPC_INFO:
604         {
605                 struct shminfo64 shminfo;
606
607                 err = security_shm_shmctl(NULL, cmd);
608                 if (err)
609                         return err;
610
611                 memset(&shminfo,0,sizeof(shminfo));
612                 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
613                 shminfo.shmmax = ns->shm_ctlmax;
614                 shminfo.shmall = ns->shm_ctlall;
615
616                 shminfo.shmmin = SHMMIN;
617                 if(copy_shminfo_to_user (buf, &shminfo, version))
618                         return -EFAULT;
619                 /* reading a integer is always atomic */
620                 err = ipc_get_maxid(&shm_ids(ns));
621                 if(err<0)
622                         err = 0;
623                 goto out;
624         }
625         case SHM_INFO:
626         {
627                 struct shm_info shm_info;
628
629                 err = security_shm_shmctl(NULL, cmd);
630                 if (err)
631                         return err;
632
633                 memset(&shm_info,0,sizeof(shm_info));
634                 mutex_lock(&shm_ids(ns).mutex);
635                 shm_info.used_ids = shm_ids(ns).in_use;
636                 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
637                 shm_info.shm_tot = ns->shm_tot;
638                 shm_info.swap_attempts = 0;
639                 shm_info.swap_successes = 0;
640                 err = ipc_get_maxid(&shm_ids(ns));
641                 mutex_unlock(&shm_ids(ns).mutex);
642                 if(copy_to_user (buf, &shm_info, sizeof(shm_info))) {
643                         err = -EFAULT;
644                         goto out;
645                 }
646
647                 err = err < 0 ? 0 : err;
648                 goto out;
649         }
650         case SHM_STAT:
651         case IPC_STAT:
652         {
653                 struct shmid64_ds tbuf;
654                 int result;
655                 memset(&tbuf, 0, sizeof(tbuf));
656                 shp = shm_lock(ns, shmid);
657                 if(shp==NULL) {
658                         err = -EINVAL;
659                         goto out;
660                 } else if (cmd == SHM_STAT) {
661                         result = shp->shm_perm.id;
662                 } else {
663                         err = shm_checkid(ns, shp,shmid);
664                         if(err)
665                                 goto out_unlock;
666                         result = 0;
667                 }
668                 err=-EACCES;
669                 if (ipcperms (&shp->shm_perm, S_IRUGO))
670                         goto out_unlock;
671                 err = security_shm_shmctl(shp, cmd);
672                 if (err)
673                         goto out_unlock;
674                 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
675                 tbuf.shm_segsz  = shp->shm_segsz;
676                 tbuf.shm_atime  = shp->shm_atim;
677                 tbuf.shm_dtime  = shp->shm_dtim;
678                 tbuf.shm_ctime  = shp->shm_ctim;
679                 tbuf.shm_cpid   = shp->shm_cprid;
680                 tbuf.shm_lpid   = shp->shm_lprid;
681                 tbuf.shm_nattch = shp->shm_nattch;
682                 shm_unlock(shp);
683                 if(copy_shmid_to_user (buf, &tbuf, version))
684                         err = -EFAULT;
685                 else
686                         err = result;
687                 goto out;
688         }
689         case SHM_LOCK:
690         case SHM_UNLOCK:
691         {
692                 shp = shm_lock(ns, shmid);
693                 if(shp==NULL) {
694                         err = -EINVAL;
695                         goto out;
696                 }
697                 err = shm_checkid(ns, shp,shmid);
698                 if(err)
699                         goto out_unlock;
700
701                 err = audit_ipc_obj(&(shp->shm_perm));
702                 if (err)
703                         goto out_unlock;
704
705                 if (!capable(CAP_IPC_LOCK)) {
706                         err = -EPERM;
707                         if (current->euid != shp->shm_perm.uid &&
708                             current->euid != shp->shm_perm.cuid)
709                                 goto out_unlock;
710                         if (cmd == SHM_LOCK &&
711                             !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur)
712                                 goto out_unlock;
713                 }
714
715                 err = security_shm_shmctl(shp, cmd);
716                 if (err)
717                         goto out_unlock;
718                 
719                 if(cmd==SHM_LOCK) {
720                         struct user_struct * user = current->user;
721                         if (!is_file_hugepages(shp->shm_file)) {
722                                 err = shmem_lock(shp->shm_file, 1, user);
723                                 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)){
724                                         shp->shm_perm.mode |= SHM_LOCKED;
725                                         shp->mlock_user = user;
726                                 }
727                         }
728                 } else if (!is_file_hugepages(shp->shm_file)) {
729                         shmem_lock(shp->shm_file, 0, shp->mlock_user);
730                         shp->shm_perm.mode &= ~SHM_LOCKED;
731                         shp->mlock_user = NULL;
732                 }
733                 shm_unlock(shp);
734                 goto out;
735         }
736         case IPC_RMID:
737         {
738                 /*
739                  *      We cannot simply remove the file. The SVID states
740                  *      that the block remains until the last person
741                  *      detaches from it, then is deleted. A shmat() on
742                  *      an RMID segment is legal in older Linux and if 
743                  *      we change it apps break...
744                  *
745                  *      Instead we set a destroyed flag, and then blow
746                  *      the name away when the usage hits zero.
747                  */
748                 mutex_lock(&shm_ids(ns).mutex);
749                 shp = shm_lock(ns, shmid);
750                 err = -EINVAL;
751                 if (shp == NULL) 
752                         goto out_up;
753                 err = shm_checkid(ns, shp, shmid);
754                 if(err)
755                         goto out_unlock_up;
756
757                 err = audit_ipc_obj(&(shp->shm_perm));
758                 if (err)
759                         goto out_unlock_up;
760
761                 if (current->euid != shp->shm_perm.uid &&
762                     current->euid != shp->shm_perm.cuid && 
763                     !capable(CAP_SYS_ADMIN)) {
764                         err=-EPERM;
765                         goto out_unlock_up;
766                 }
767
768                 err = security_shm_shmctl(shp, cmd);
769                 if (err)
770                         goto out_unlock_up;
771
772                 do_shm_rmid(ns, shp);
773                 mutex_unlock(&shm_ids(ns).mutex);
774                 goto out;
775         }
776
777         case IPC_SET:
778         {
779                 if (copy_shmid_from_user (&setbuf, buf, version)) {
780                         err = -EFAULT;
781                         goto out;
782                 }
783                 mutex_lock(&shm_ids(ns).mutex);
784                 shp = shm_lock(ns, shmid);
785                 err=-EINVAL;
786                 if(shp==NULL)
787                         goto out_up;
788                 err = shm_checkid(ns, shp,shmid);
789                 if(err)
790                         goto out_unlock_up;
791                 err = audit_ipc_obj(&(shp->shm_perm));
792                 if (err)
793                         goto out_unlock_up;
794                 err = audit_ipc_set_perm(0, setbuf.uid, setbuf.gid, setbuf.mode);
795                 if (err)
796                         goto out_unlock_up;
797                 err=-EPERM;
798                 if (current->euid != shp->shm_perm.uid &&
799                     current->euid != shp->shm_perm.cuid && 
800                     !capable(CAP_SYS_ADMIN)) {
801                         goto out_unlock_up;
802                 }
803
804                 err = security_shm_shmctl(shp, cmd);
805                 if (err)
806                         goto out_unlock_up;
807                 
808                 shp->shm_perm.uid = setbuf.uid;
809                 shp->shm_perm.gid = setbuf.gid;
810                 shp->shm_perm.mode = (shp->shm_perm.mode & ~S_IRWXUGO)
811                         | (setbuf.mode & S_IRWXUGO);
812                 shp->shm_ctim = get_seconds();
813                 break;
814         }
815
816         default:
817                 err = -EINVAL;
818                 goto out;
819         }
820
821         err = 0;
822 out_unlock_up:
823         shm_unlock(shp);
824 out_up:
825         mutex_unlock(&shm_ids(ns).mutex);
826         goto out;
827 out_unlock:
828         shm_unlock(shp);
829 out:
830         return err;
831 }
832
833 /*
834  * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
835  *
836  * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
837  * "raddr" thing points to kernel space, and there has to be a wrapper around
838  * this.
839  */
840 long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
841 {
842         struct shmid_kernel *shp;
843         unsigned long addr;
844         unsigned long size;
845         struct file * file;
846         int    err;
847         unsigned long flags;
848         unsigned long prot;
849         int acc_mode;
850         unsigned long user_addr;
851         struct ipc_namespace *ns;
852         struct shm_file_data *sfd;
853         struct path path;
854         mode_t f_mode;
855
856         err = -EINVAL;
857         if (shmid < 0)
858                 goto out;
859         else if ((addr = (ulong)shmaddr)) {
860                 if (addr & (SHMLBA-1)) {
861                         if (shmflg & SHM_RND)
862                                 addr &= ~(SHMLBA-1);       /* round down */
863                         else
864 #ifndef __ARCH_FORCE_SHMLBA
865                                 if (addr & ~PAGE_MASK)
866 #endif
867                                         goto out;
868                 }
869                 flags = MAP_SHARED | MAP_FIXED;
870         } else {
871                 if ((shmflg & SHM_REMAP))
872                         goto out;
873
874                 flags = MAP_SHARED;
875         }
876
877         if (shmflg & SHM_RDONLY) {
878                 prot = PROT_READ;
879                 acc_mode = S_IRUGO;
880                 f_mode = FMODE_READ;
881         } else {
882                 prot = PROT_READ | PROT_WRITE;
883                 acc_mode = S_IRUGO | S_IWUGO;
884                 f_mode = FMODE_READ | FMODE_WRITE;
885         }
886         if (shmflg & SHM_EXEC) {
887                 prot |= PROT_EXEC;
888                 acc_mode |= S_IXUGO;
889         }
890
891         /*
892          * We cannot rely on the fs check since SYSV IPC does have an
893          * additional creator id...
894          */
895         ns = current->nsproxy->ipc_ns;
896         shp = shm_lock(ns, shmid);
897         if(shp == NULL)
898                 goto out;
899
900         err = shm_checkid(ns, shp,shmid);
901         if (err)
902                 goto out_unlock;
903
904         err = -EACCES;
905         if (ipcperms(&shp->shm_perm, acc_mode))
906                 goto out_unlock;
907
908         err = security_shm_shmat(shp, shmaddr, shmflg);
909         if (err)
910                 goto out_unlock;
911
912         path.dentry = dget(shp->shm_file->f_path.dentry);
913         path.mnt    = shp->shm_file->f_path.mnt;
914         shp->shm_nattch++;
915         size = i_size_read(path.dentry->d_inode);
916         shm_unlock(shp);
917
918         err = -ENOMEM;
919         sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
920         if (!sfd)
921                 goto out_put_dentry;
922
923         err = -ENOMEM;
924
925         file = alloc_file(path.mnt, path.dentry, f_mode, &shm_file_operations);
926         if (!file)
927                 goto out_free;
928
929         file->private_data = sfd;
930         file->f_mapping = shp->shm_file->f_mapping;
931         sfd->id = shp->shm_perm.id;
932         sfd->ns = get_ipc_ns(ns);
933         sfd->file = shp->shm_file;
934         sfd->vm_ops = NULL;
935
936         down_write(&current->mm->mmap_sem);
937         if (addr && !(shmflg & SHM_REMAP)) {
938                 err = -EINVAL;
939                 if (find_vma_intersection(current->mm, addr, addr + size))
940                         goto invalid;
941                 /*
942                  * If shm segment goes below stack, make sure there is some
943                  * space left for the stack to grow (at least 4 pages).
944                  */
945                 if (addr < current->mm->start_stack &&
946                     addr > current->mm->start_stack - size - PAGE_SIZE * 5)
947                         goto invalid;
948         }
949                 
950         user_addr = do_mmap (file, addr, size, prot, flags, 0);
951         *raddr = user_addr;
952         err = 0;
953         if (IS_ERR_VALUE(user_addr))
954                 err = (long)user_addr;
955 invalid:
956         up_write(&current->mm->mmap_sem);
957
958         fput(file);
959
960 out_nattch:
961         mutex_lock(&shm_ids(ns).mutex);
962         shp = shm_lock(ns, shmid);
963         BUG_ON(!shp);
964         shp->shm_nattch--;
965         if(shp->shm_nattch == 0 &&
966            shp->shm_perm.mode & SHM_DEST)
967                 shm_destroy(ns, shp);
968         else
969                 shm_unlock(shp);
970         mutex_unlock(&shm_ids(ns).mutex);
971
972 out:
973         return err;
974
975 out_unlock:
976         shm_unlock(shp);
977         goto out;
978
979 out_free:
980         kfree(sfd);
981 out_put_dentry:
982         dput(path.dentry);
983         goto out_nattch;
984 }
985
986 asmlinkage long sys_shmat(int shmid, char __user *shmaddr, int shmflg)
987 {
988         unsigned long ret;
989         long err;
990
991         err = do_shmat(shmid, shmaddr, shmflg, &ret);
992         if (err)
993                 return err;
994         force_successful_syscall_return();
995         return (long)ret;
996 }
997
998 /*
999  * detach and kill segment if marked destroyed.
1000  * The work is done in shm_close.
1001  */
1002 asmlinkage long sys_shmdt(char __user *shmaddr)
1003 {
1004         struct mm_struct *mm = current->mm;
1005         struct vm_area_struct *vma, *next;
1006         unsigned long addr = (unsigned long)shmaddr;
1007         loff_t size = 0;
1008         int retval = -EINVAL;
1009
1010         if (addr & ~PAGE_MASK)
1011                 return retval;
1012
1013         down_write(&mm->mmap_sem);
1014
1015         /*
1016          * This function tries to be smart and unmap shm segments that
1017          * were modified by partial mlock or munmap calls:
1018          * - It first determines the size of the shm segment that should be
1019          *   unmapped: It searches for a vma that is backed by shm and that
1020          *   started at address shmaddr. It records it's size and then unmaps
1021          *   it.
1022          * - Then it unmaps all shm vmas that started at shmaddr and that
1023          *   are within the initially determined size.
1024          * Errors from do_munmap are ignored: the function only fails if
1025          * it's called with invalid parameters or if it's called to unmap
1026          * a part of a vma. Both calls in this function are for full vmas,
1027          * the parameters are directly copied from the vma itself and always
1028          * valid - therefore do_munmap cannot fail. (famous last words?)
1029          */
1030         /*
1031          * If it had been mremap()'d, the starting address would not
1032          * match the usual checks anyway. So assume all vma's are
1033          * above the starting address given.
1034          */
1035         vma = find_vma(mm, addr);
1036
1037         while (vma) {
1038                 next = vma->vm_next;
1039
1040                 /*
1041                  * Check if the starting address would match, i.e. it's
1042                  * a fragment created by mprotect() and/or munmap(), or it
1043                  * otherwise it starts at this address with no hassles.
1044                  */
1045                 if ((vma->vm_ops == &shm_vm_ops) &&
1046                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1047
1048
1049                         size = vma->vm_file->f_path.dentry->d_inode->i_size;
1050                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1051                         /*
1052                          * We discovered the size of the shm segment, so
1053                          * break out of here and fall through to the next
1054                          * loop that uses the size information to stop
1055                          * searching for matching vma's.
1056                          */
1057                         retval = 0;
1058                         vma = next;
1059                         break;
1060                 }
1061                 vma = next;
1062         }
1063
1064         /*
1065          * We need look no further than the maximum address a fragment
1066          * could possibly have landed at. Also cast things to loff_t to
1067          * prevent overflows and make comparisions vs. equal-width types.
1068          */
1069         size = PAGE_ALIGN(size);
1070         while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1071                 next = vma->vm_next;
1072
1073                 /* finding a matching vma now does not alter retval */
1074                 if ((vma->vm_ops == &shm_vm_ops) &&
1075                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1076
1077                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1078                 vma = next;
1079         }
1080
1081         up_write(&mm->mmap_sem);
1082         return retval;
1083 }
1084
1085 #ifdef CONFIG_PROC_FS
1086 static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1087 {
1088         struct shmid_kernel *shp = it;
1089         char *format;
1090
1091 #define SMALL_STRING "%10d %10d  %4o %10u %5u %5u  %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1092 #define BIG_STRING   "%10d %10d  %4o %21u %5u %5u  %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1093
1094         if (sizeof(size_t) <= sizeof(int))
1095                 format = SMALL_STRING;
1096         else
1097                 format = BIG_STRING;
1098         return seq_printf(s, format,
1099                           shp->shm_perm.key,
1100                           shp->shm_perm.id,
1101                           shp->shm_perm.mode,
1102                           shp->shm_segsz,
1103                           shp->shm_cprid,
1104                           shp->shm_lprid,
1105                           shp->shm_nattch,
1106                           shp->shm_perm.uid,
1107                           shp->shm_perm.gid,
1108                           shp->shm_perm.cuid,
1109                           shp->shm_perm.cgid,
1110                           shp->shm_atim,
1111                           shp->shm_dtim,
1112                           shp->shm_ctim);
1113 }
1114 #endif