ipc/shm.c: make 2 functions static
[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 *ns, key_t key,
72                 int shmflg, size_t size);
73 static void shm_open(struct vm_area_struct *vma);
74 static void shm_close(struct vm_area_struct *vma);
75 static void shm_destroy (struct ipc_namespace *ns, struct shmid_kernel *shp);
76 #ifdef CONFIG_PROC_FS
77 static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
78 #endif
79
80 static void __shm_init_ns(struct ipc_namespace *ns, struct ipc_ids *ids)
81 {
82         ns->ids[IPC_SHM_IDS] = ids;
83         ns->shm_ctlmax = SHMMAX;
84         ns->shm_ctlall = SHMALL;
85         ns->shm_ctlmni = SHMMNI;
86         ns->shm_tot = 0;
87         ipc_init_ids(ids, 1);
88 }
89
90 static void do_shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *shp)
91 {
92         if (shp->shm_nattch){
93                 shp->shm_perm.mode |= SHM_DEST;
94                 /* Do not find it any more */
95                 shp->shm_perm.key = IPC_PRIVATE;
96                 shm_unlock(shp);
97         } else
98                 shm_destroy(ns, shp);
99 }
100
101 int shm_init_ns(struct ipc_namespace *ns)
102 {
103         struct ipc_ids *ids;
104
105         ids = kmalloc(sizeof(struct ipc_ids), GFP_KERNEL);
106         if (ids == NULL)
107                 return -ENOMEM;
108
109         __shm_init_ns(ns, ids);
110         return 0;
111 }
112
113 void shm_exit_ns(struct ipc_namespace *ns)
114 {
115         int i;
116         struct shmid_kernel *shp;
117
118         mutex_lock(&shm_ids(ns).mutex);
119         for (i = 0; i <= shm_ids(ns).max_id; i++) {
120                 shp = shm_lock(ns, i);
121                 if (shp == NULL)
122                         continue;
123
124                 do_shm_rmid(ns, shp);
125         }
126         mutex_unlock(&shm_ids(ns).mutex);
127
128         ipc_fini_ids(ns->ids[IPC_SHM_IDS]);
129         kfree(ns->ids[IPC_SHM_IDS]);
130         ns->ids[IPC_SHM_IDS] = NULL;
131 }
132
133 void __init shm_init (void)
134 {
135         __shm_init_ns(&init_ipc_ns, &init_shm_ids);
136         ipc_init_proc_interface("sysvipc/shm",
137                                 "       key      shmid perms       size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime\n",
138                                 IPC_SHM_IDS, sysvipc_shm_proc_show);
139 }
140
141 static inline int shm_checkid(struct ipc_namespace *ns,
142                 struct shmid_kernel *s, int id)
143 {
144         if (ipc_checkid(&shm_ids(ns), &s->shm_perm, id))
145                 return -EIDRM;
146         return 0;
147 }
148
149 static inline struct shmid_kernel *shm_rmid(struct ipc_namespace *ns, int id)
150 {
151         return (struct shmid_kernel *)ipc_rmid(&shm_ids(ns), id);
152 }
153
154 static inline int shm_addid(struct ipc_namespace *ns, struct shmid_kernel *shp)
155 {
156         return ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
157 }
158
159
160
161 /* This is called by fork, once for every shm attach. */
162 static void shm_open(struct vm_area_struct *vma)
163 {
164         struct file *file = vma->vm_file;
165         struct shm_file_data *sfd = shm_file_data(file);
166         struct shmid_kernel *shp;
167
168         shp = shm_lock(sfd->ns, sfd->id);
169         BUG_ON(!shp);
170         shp->shm_atim = get_seconds();
171         shp->shm_lprid = current->tgid;
172         shp->shm_nattch++;
173         shm_unlock(shp);
174 }
175
176 /*
177  * shm_destroy - free the struct shmid_kernel
178  *
179  * @shp: struct to free
180  *
181  * It has to be called with shp and shm_ids.mutex locked,
182  * but returns with shp unlocked and freed.
183  */
184 static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
185 {
186         ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
187         shm_rmid(ns, shp->id);
188         shm_unlock(shp);
189         if (!is_file_hugepages(shp->shm_file))
190                 shmem_lock(shp->shm_file, 0, shp->mlock_user);
191         else
192                 user_shm_unlock(shp->shm_file->f_path.dentry->d_inode->i_size,
193                                                 shp->mlock_user);
194         fput (shp->shm_file);
195         security_shm_free(shp);
196         ipc_rcu_putref(shp);
197 }
198
199 /*
200  * remove the attach descriptor vma.
201  * free memory for segment if it is marked destroyed.
202  * The descriptor has already been removed from the current->mm->mmap list
203  * and will later be kfree()d.
204  */
205 static void shm_close(struct vm_area_struct *vma)
206 {
207         struct file * file = vma->vm_file;
208         struct shm_file_data *sfd = shm_file_data(file);
209         struct shmid_kernel *shp;
210         struct ipc_namespace *ns = sfd->ns;
211
212         mutex_lock(&shm_ids(ns).mutex);
213         /* remove from the list of attaches of the shm segment */
214         shp = shm_lock(ns, sfd->id);
215         BUG_ON(!shp);
216         shp->shm_lprid = current->tgid;
217         shp->shm_dtim = get_seconds();
218         shp->shm_nattch--;
219         if(shp->shm_nattch == 0 &&
220            shp->shm_perm.mode & SHM_DEST)
221                 shm_destroy(ns, shp);
222         else
223                 shm_unlock(shp);
224         mutex_unlock(&shm_ids(ns).mutex);
225 }
226
227 static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
228 {
229         struct file *file = vma->vm_file;
230         struct shm_file_data *sfd = shm_file_data(file);
231
232         return sfd->vm_ops->fault(vma, vmf);
233 }
234
235 #ifdef CONFIG_NUMA
236 static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
237 {
238         struct file *file = vma->vm_file;
239         struct shm_file_data *sfd = shm_file_data(file);
240         int err = 0;
241         if (sfd->vm_ops->set_policy)
242                 err = sfd->vm_ops->set_policy(vma, new);
243         return err;
244 }
245
246 static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
247                                         unsigned long addr)
248 {
249         struct file *file = vma->vm_file;
250         struct shm_file_data *sfd = shm_file_data(file);
251         struct mempolicy *pol = NULL;
252
253         if (sfd->vm_ops->get_policy)
254                 pol = sfd->vm_ops->get_policy(vma, addr);
255         else if (vma->vm_policy)
256                 pol = vma->vm_policy;
257         else
258                 pol = current->mempolicy;
259         return pol;
260 }
261 #endif
262
263 static int shm_mmap(struct file * file, struct vm_area_struct * vma)
264 {
265         struct shm_file_data *sfd = shm_file_data(file);
266         int ret;
267
268         ret = sfd->file->f_op->mmap(sfd->file, vma);
269         if (ret != 0)
270                 return ret;
271         sfd->vm_ops = vma->vm_ops;
272 #ifdef CONFIG_MMU
273         BUG_ON(!sfd->vm_ops->fault);
274 #endif
275         vma->vm_ops = &shm_vm_ops;
276         shm_open(vma);
277
278         return ret;
279 }
280
281 static int shm_release(struct inode *ino, struct file *file)
282 {
283         struct shm_file_data *sfd = shm_file_data(file);
284
285         put_ipc_ns(sfd->ns);
286         shm_file_data(file) = NULL;
287         kfree(sfd);
288         return 0;
289 }
290
291 static int shm_fsync(struct file *file, struct dentry *dentry, int datasync)
292 {
293         int (*fsync) (struct file *, struct dentry *, int datasync);
294         struct shm_file_data *sfd = shm_file_data(file);
295         int ret = -EINVAL;
296
297         fsync = sfd->file->f_op->fsync;
298         if (fsync)
299                 ret = fsync(sfd->file, sfd->file->f_path.dentry, datasync);
300         return ret;
301 }
302
303 static unsigned long shm_get_unmapped_area(struct file *file,
304         unsigned long addr, unsigned long len, unsigned long pgoff,
305         unsigned long flags)
306 {
307         struct shm_file_data *sfd = shm_file_data(file);
308         return get_unmapped_area(sfd->file, addr, len, pgoff, flags);
309 }
310
311 int is_file_shm_hugepages(struct file *file)
312 {
313         int ret = 0;
314
315         if (file->f_op == &shm_file_operations) {
316                 struct shm_file_data *sfd;
317                 sfd = shm_file_data(file);
318                 ret = is_file_hugepages(sfd->file);
319         }
320         return ret;
321 }
322
323 static const struct file_operations shm_file_operations = {
324         .mmap           = shm_mmap,
325         .fsync          = shm_fsync,
326         .release        = shm_release,
327         .get_unmapped_area      = shm_get_unmapped_area,
328 };
329
330 static struct vm_operations_struct shm_vm_ops = {
331         .open   = shm_open,     /* callback for a new vm-area open */
332         .close  = shm_close,    /* callback for when the vm-area is released */
333         .fault  = shm_fault,
334 #if defined(CONFIG_NUMA)
335         .set_policy = shm_set_policy,
336         .get_policy = shm_get_policy,
337 #endif
338 };
339
340 static int newseg (struct ipc_namespace *ns, key_t key, int shmflg, size_t size)
341 {
342         int error;
343         struct shmid_kernel *shp;
344         int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
345         struct file * file;
346         char name[13];
347         int id;
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 takes care of mlock user accounting */
373                 file = hugetlb_file_setup(name, size);
374                 shp->mlock_user = current->user;
375         } else {
376                 int acctflag = VM_ACCOUNT;
377                 /*
378                  * Do not allow no accounting for OVERCOMMIT_NEVER, even
379                  * if it's asked for.
380                  */
381                 if  ((shmflg & SHM_NORESERVE) &&
382                                 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
383                         acctflag = 0;
384                 file = shmem_file_setup(name, size, acctflag);
385         }
386         error = PTR_ERR(file);
387         if (IS_ERR(file))
388                 goto no_file;
389
390         error = -ENOSPC;
391         id = shm_addid(ns, shp);
392         if(id == -1) 
393                 goto no_id;
394
395         shp->shm_cprid = current->tgid;
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->id = shm_buildid(ns, id, shp->shm_perm.seq);
402         shp->shm_file = file;
403         /*
404          * shmid gets reported as "inode#" in /proc/pid/maps.
405          * proc-ps tools use this. Changing this will break them.
406          */
407         file->f_dentry->d_inode->i_ino = shp->id;
408
409         ns->shm_tot += numpages;
410         shm_unlock(shp);
411         return shp->id;
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 asmlinkage long sys_shmget (key_t key, size_t size, int shmflg)
422 {
423         struct shmid_kernel *shp;
424         int err, id = 0;
425         struct ipc_namespace *ns;
426
427         ns = current->nsproxy->ipc_ns;
428
429         mutex_lock(&shm_ids(ns).mutex);
430         if (key == IPC_PRIVATE) {
431                 err = newseg(ns, key, shmflg, size);
432         } else if ((id = ipc_findkey(&shm_ids(ns), key)) == -1) {
433                 if (!(shmflg & IPC_CREAT))
434                         err = -ENOENT;
435                 else
436                         err = newseg(ns, key, shmflg, size);
437         } else if ((shmflg & IPC_CREAT) && (shmflg & IPC_EXCL)) {
438                 err = -EEXIST;
439         } else {
440                 shp = shm_lock(ns, id);
441                 BUG_ON(shp==NULL);
442                 if (shp->shm_segsz < size)
443                         err = -EINVAL;
444                 else if (ipcperms(&shp->shm_perm, shmflg))
445                         err = -EACCES;
446                 else {
447                         int shmid = shm_buildid(ns, id, shp->shm_perm.seq);
448                         err = security_shm_associate(shp, shmflg);
449                         if (!err)
450                                 err = shmid;
451                 }
452                 shm_unlock(shp);
453         }
454         mutex_unlock(&shm_ids(ns).mutex);
455
456         return err;
457 }
458
459 static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
460 {
461         switch(version) {
462         case IPC_64:
463                 return copy_to_user(buf, in, sizeof(*in));
464         case IPC_OLD:
465             {
466                 struct shmid_ds out;
467
468                 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
469                 out.shm_segsz   = in->shm_segsz;
470                 out.shm_atime   = in->shm_atime;
471                 out.shm_dtime   = in->shm_dtime;
472                 out.shm_ctime   = in->shm_ctime;
473                 out.shm_cpid    = in->shm_cpid;
474                 out.shm_lpid    = in->shm_lpid;
475                 out.shm_nattch  = in->shm_nattch;
476
477                 return copy_to_user(buf, &out, sizeof(out));
478             }
479         default:
480                 return -EINVAL;
481         }
482 }
483
484 struct shm_setbuf {
485         uid_t   uid;
486         gid_t   gid;
487         mode_t  mode;
488 };      
489
490 static inline unsigned long copy_shmid_from_user(struct shm_setbuf *out, void __user *buf, int version)
491 {
492         switch(version) {
493         case IPC_64:
494             {
495                 struct shmid64_ds tbuf;
496
497                 if (copy_from_user(&tbuf, buf, sizeof(tbuf)))
498                         return -EFAULT;
499
500                 out->uid        = tbuf.shm_perm.uid;
501                 out->gid        = tbuf.shm_perm.gid;
502                 out->mode       = tbuf.shm_perm.mode;
503
504                 return 0;
505             }
506         case IPC_OLD:
507             {
508                 struct shmid_ds tbuf_old;
509
510                 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
511                         return -EFAULT;
512
513                 out->uid        = tbuf_old.shm_perm.uid;
514                 out->gid        = tbuf_old.shm_perm.gid;
515                 out->mode       = tbuf_old.shm_perm.mode;
516
517                 return 0;
518             }
519         default:
520                 return -EINVAL;
521         }
522 }
523
524 static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
525 {
526         switch(version) {
527         case IPC_64:
528                 return copy_to_user(buf, in, sizeof(*in));
529         case IPC_OLD:
530             {
531                 struct shminfo out;
532
533                 if(in->shmmax > INT_MAX)
534                         out.shmmax = INT_MAX;
535                 else
536                         out.shmmax = (int)in->shmmax;
537
538                 out.shmmin      = in->shmmin;
539                 out.shmmni      = in->shmmni;
540                 out.shmseg      = in->shmseg;
541                 out.shmall      = in->shmall; 
542
543                 return copy_to_user(buf, &out, sizeof(out));
544             }
545         default:
546                 return -EINVAL;
547         }
548 }
549
550 static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
551                 unsigned long *swp)
552 {
553         int i;
554
555         *rss = 0;
556         *swp = 0;
557
558         for (i = 0; i <= shm_ids(ns).max_id; i++) {
559                 struct shmid_kernel *shp;
560                 struct inode *inode;
561
562                 shp = shm_get(ns, i);
563                 if(!shp)
564                         continue;
565
566                 inode = shp->shm_file->f_path.dentry->d_inode;
567
568                 if (is_file_hugepages(shp->shm_file)) {
569                         struct address_space *mapping = inode->i_mapping;
570                         *rss += (HPAGE_SIZE/PAGE_SIZE)*mapping->nrpages;
571                 } else {
572                         struct shmem_inode_info *info = SHMEM_I(inode);
573                         spin_lock(&info->lock);
574                         *rss += inode->i_mapping->nrpages;
575                         *swp += info->swapped;
576                         spin_unlock(&info->lock);
577                 }
578         }
579 }
580
581 asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
582 {
583         struct shm_setbuf setbuf;
584         struct shmid_kernel *shp;
585         int err, version;
586         struct ipc_namespace *ns;
587
588         if (cmd < 0 || shmid < 0) {
589                 err = -EINVAL;
590                 goto out;
591         }
592
593         version = ipc_parse_version(&cmd);
594         ns = current->nsproxy->ipc_ns;
595
596         switch (cmd) { /* replace with proc interface ? */
597         case IPC_INFO:
598         {
599                 struct shminfo64 shminfo;
600
601                 err = security_shm_shmctl(NULL, cmd);
602                 if (err)
603                         return err;
604
605                 memset(&shminfo,0,sizeof(shminfo));
606                 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
607                 shminfo.shmmax = ns->shm_ctlmax;
608                 shminfo.shmall = ns->shm_ctlall;
609
610                 shminfo.shmmin = SHMMIN;
611                 if(copy_shminfo_to_user (buf, &shminfo, version))
612                         return -EFAULT;
613                 /* reading a integer is always atomic */
614                 err= shm_ids(ns).max_id;
615                 if(err<0)
616                         err = 0;
617                 goto out;
618         }
619         case SHM_INFO:
620         {
621                 struct shm_info shm_info;
622
623                 err = security_shm_shmctl(NULL, cmd);
624                 if (err)
625                         return err;
626
627                 memset(&shm_info,0,sizeof(shm_info));
628                 mutex_lock(&shm_ids(ns).mutex);
629                 shm_info.used_ids = shm_ids(ns).in_use;
630                 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
631                 shm_info.shm_tot = ns->shm_tot;
632                 shm_info.swap_attempts = 0;
633                 shm_info.swap_successes = 0;
634                 err = shm_ids(ns).max_id;
635                 mutex_unlock(&shm_ids(ns).mutex);
636                 if(copy_to_user (buf, &shm_info, sizeof(shm_info))) {
637                         err = -EFAULT;
638                         goto out;
639                 }
640
641                 err = err < 0 ? 0 : err;
642                 goto out;
643         }
644         case SHM_STAT:
645         case IPC_STAT:
646         {
647                 struct shmid64_ds tbuf;
648                 int result;
649                 memset(&tbuf, 0, sizeof(tbuf));
650                 shp = shm_lock(ns, shmid);
651                 if(shp==NULL) {
652                         err = -EINVAL;
653                         goto out;
654                 } else if(cmd==SHM_STAT) {
655                         err = -EINVAL;
656                         if (shmid > shm_ids(ns).max_id)
657                                 goto out_unlock;
658                         result = shm_buildid(ns, shmid, shp->shm_perm.seq);
659                 } else {
660                         err = shm_checkid(ns, shp,shmid);
661                         if(err)
662                                 goto out_unlock;
663                         result = 0;
664                 }
665                 err=-EACCES;
666                 if (ipcperms (&shp->shm_perm, S_IRUGO))
667                         goto out_unlock;
668                 err = security_shm_shmctl(shp, cmd);
669                 if (err)
670                         goto out_unlock;
671                 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
672                 tbuf.shm_segsz  = shp->shm_segsz;
673                 tbuf.shm_atime  = shp->shm_atim;
674                 tbuf.shm_dtime  = shp->shm_dtim;
675                 tbuf.shm_ctime  = shp->shm_ctim;
676                 tbuf.shm_cpid   = shp->shm_cprid;
677                 tbuf.shm_lpid   = shp->shm_lprid;
678                 tbuf.shm_nattch = shp->shm_nattch;
679                 shm_unlock(shp);
680                 if(copy_shmid_to_user (buf, &tbuf, version))
681                         err = -EFAULT;
682                 else
683                         err = result;
684                 goto out;
685         }
686         case SHM_LOCK:
687         case SHM_UNLOCK:
688         {
689                 shp = shm_lock(ns, shmid);
690                 if(shp==NULL) {
691                         err = -EINVAL;
692                         goto out;
693                 }
694                 err = shm_checkid(ns, shp,shmid);
695                 if(err)
696                         goto out_unlock;
697
698                 err = audit_ipc_obj(&(shp->shm_perm));
699                 if (err)
700                         goto out_unlock;
701
702                 if (!capable(CAP_IPC_LOCK)) {
703                         err = -EPERM;
704                         if (current->euid != shp->shm_perm.uid &&
705                             current->euid != shp->shm_perm.cuid)
706                                 goto out_unlock;
707                         if (cmd == SHM_LOCK &&
708                             !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur)
709                                 goto out_unlock;
710                 }
711
712                 err = security_shm_shmctl(shp, cmd);
713                 if (err)
714                         goto out_unlock;
715                 
716                 if(cmd==SHM_LOCK) {
717                         struct user_struct * user = current->user;
718                         if (!is_file_hugepages(shp->shm_file)) {
719                                 err = shmem_lock(shp->shm_file, 1, user);
720                                 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)){
721                                         shp->shm_perm.mode |= SHM_LOCKED;
722                                         shp->mlock_user = user;
723                                 }
724                         }
725                 } else if (!is_file_hugepages(shp->shm_file)) {
726                         shmem_lock(shp->shm_file, 0, shp->mlock_user);
727                         shp->shm_perm.mode &= ~SHM_LOCKED;
728                         shp->mlock_user = NULL;
729                 }
730                 shm_unlock(shp);
731                 goto out;
732         }
733         case IPC_RMID:
734         {
735                 /*
736                  *      We cannot simply remove the file. The SVID states
737                  *      that the block remains until the last person
738                  *      detaches from it, then is deleted. A shmat() on
739                  *      an RMID segment is legal in older Linux and if 
740                  *      we change it apps break...
741                  *
742                  *      Instead we set a destroyed flag, and then blow
743                  *      the name away when the usage hits zero.
744                  */
745                 mutex_lock(&shm_ids(ns).mutex);
746                 shp = shm_lock(ns, shmid);
747                 err = -EINVAL;
748                 if (shp == NULL) 
749                         goto out_up;
750                 err = shm_checkid(ns, shp, shmid);
751                 if(err)
752                         goto out_unlock_up;
753
754                 err = audit_ipc_obj(&(shp->shm_perm));
755                 if (err)
756                         goto out_unlock_up;
757
758                 if (current->euid != shp->shm_perm.uid &&
759                     current->euid != shp->shm_perm.cuid && 
760                     !capable(CAP_SYS_ADMIN)) {
761                         err=-EPERM;
762                         goto out_unlock_up;
763                 }
764
765                 err = security_shm_shmctl(shp, cmd);
766                 if (err)
767                         goto out_unlock_up;
768
769                 do_shm_rmid(ns, shp);
770                 mutex_unlock(&shm_ids(ns).mutex);
771                 goto out;
772         }
773
774         case IPC_SET:
775         {
776                 if (copy_shmid_from_user (&setbuf, buf, version)) {
777                         err = -EFAULT;
778                         goto out;
779                 }
780                 mutex_lock(&shm_ids(ns).mutex);
781                 shp = shm_lock(ns, shmid);
782                 err=-EINVAL;
783                 if(shp==NULL)
784                         goto out_up;
785                 err = shm_checkid(ns, shp,shmid);
786                 if(err)
787                         goto out_unlock_up;
788                 err = audit_ipc_obj(&(shp->shm_perm));
789                 if (err)
790                         goto out_unlock_up;
791                 err = audit_ipc_set_perm(0, setbuf.uid, setbuf.gid, setbuf.mode);
792                 if (err)
793                         goto out_unlock_up;
794                 err=-EPERM;
795                 if (current->euid != shp->shm_perm.uid &&
796                     current->euid != shp->shm_perm.cuid && 
797                     !capable(CAP_SYS_ADMIN)) {
798                         goto out_unlock_up;
799                 }
800
801                 err = security_shm_shmctl(shp, cmd);
802                 if (err)
803                         goto out_unlock_up;
804                 
805                 shp->shm_perm.uid = setbuf.uid;
806                 shp->shm_perm.gid = setbuf.gid;
807                 shp->shm_perm.mode = (shp->shm_perm.mode & ~S_IRWXUGO)
808                         | (setbuf.mode & S_IRWXUGO);
809                 shp->shm_ctim = get_seconds();
810                 break;
811         }
812
813         default:
814                 err = -EINVAL;
815                 goto out;
816         }
817
818         err = 0;
819 out_unlock_up:
820         shm_unlock(shp);
821 out_up:
822         mutex_unlock(&shm_ids(ns).mutex);
823         goto out;
824 out_unlock:
825         shm_unlock(shp);
826 out:
827         return err;
828 }
829
830 /*
831  * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
832  *
833  * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
834  * "raddr" thing points to kernel space, and there has to be a wrapper around
835  * this.
836  */
837 long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
838 {
839         struct shmid_kernel *shp;
840         unsigned long addr;
841         unsigned long size;
842         struct file * file;
843         int    err;
844         unsigned long flags;
845         unsigned long prot;
846         int acc_mode;
847         unsigned long user_addr;
848         struct ipc_namespace *ns;
849         struct shm_file_data *sfd;
850         struct path path;
851         mode_t f_mode;
852
853         err = -EINVAL;
854         if (shmid < 0)
855                 goto out;
856         else if ((addr = (ulong)shmaddr)) {
857                 if (addr & (SHMLBA-1)) {
858                         if (shmflg & SHM_RND)
859                                 addr &= ~(SHMLBA-1);       /* round down */
860                         else
861 #ifndef __ARCH_FORCE_SHMLBA
862                                 if (addr & ~PAGE_MASK)
863 #endif
864                                         goto out;
865                 }
866                 flags = MAP_SHARED | MAP_FIXED;
867         } else {
868                 if ((shmflg & SHM_REMAP))
869                         goto out;
870
871                 flags = MAP_SHARED;
872         }
873
874         if (shmflg & SHM_RDONLY) {
875                 prot = PROT_READ;
876                 acc_mode = S_IRUGO;
877                 f_mode = FMODE_READ;
878         } else {
879                 prot = PROT_READ | PROT_WRITE;
880                 acc_mode = S_IRUGO | S_IWUGO;
881                 f_mode = FMODE_READ | FMODE_WRITE;
882         }
883         if (shmflg & SHM_EXEC) {
884                 prot |= PROT_EXEC;
885                 acc_mode |= S_IXUGO;
886         }
887
888         /*
889          * We cannot rely on the fs check since SYSV IPC does have an
890          * additional creator id...
891          */
892         ns = current->nsproxy->ipc_ns;
893         shp = shm_lock(ns, shmid);
894         if(shp == NULL)
895                 goto out;
896
897         err = shm_checkid(ns, shp,shmid);
898         if (err)
899                 goto out_unlock;
900
901         err = -EACCES;
902         if (ipcperms(&shp->shm_perm, acc_mode))
903                 goto out_unlock;
904
905         err = security_shm_shmat(shp, shmaddr, shmflg);
906         if (err)
907                 goto out_unlock;
908
909         path.dentry = dget(shp->shm_file->f_path.dentry);
910         path.mnt    = mntget(shp->shm_file->f_path.mnt);
911         shp->shm_nattch++;
912         size = i_size_read(path.dentry->d_inode);
913         shm_unlock(shp);
914
915         err = -ENOMEM;
916         sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
917         if (!sfd)
918                 goto out_put_path;
919
920         err = -ENOMEM;
921         file = get_empty_filp();
922         if (!file)
923                 goto out_free;
924
925         file->f_op = &shm_file_operations;
926         file->private_data = sfd;
927         file->f_path = path;
928         file->f_mapping = shp->shm_file->f_mapping;
929         file->f_mode = f_mode;
930         sfd->id = shp->id;
931         sfd->ns = get_ipc_ns(ns);
932         sfd->file = shp->shm_file;
933         sfd->vm_ops = NULL;
934
935         down_write(&current->mm->mmap_sem);
936         if (addr && !(shmflg & SHM_REMAP)) {
937                 err = -EINVAL;
938                 if (find_vma_intersection(current->mm, addr, addr + size))
939                         goto invalid;
940                 /*
941                  * If shm segment goes below stack, make sure there is some
942                  * space left for the stack to grow (at least 4 pages).
943                  */
944                 if (addr < current->mm->start_stack &&
945                     addr > current->mm->start_stack - size - PAGE_SIZE * 5)
946                         goto invalid;
947         }
948                 
949         user_addr = do_mmap (file, addr, size, prot, flags, 0);
950         *raddr = user_addr;
951         err = 0;
952         if (IS_ERR_VALUE(user_addr))
953                 err = (long)user_addr;
954 invalid:
955         up_write(&current->mm->mmap_sem);
956
957         fput(file);
958
959 out_nattch:
960         mutex_lock(&shm_ids(ns).mutex);
961         shp = shm_lock(ns, shmid);
962         BUG_ON(!shp);
963         shp->shm_nattch--;
964         if(shp->shm_nattch == 0 &&
965            shp->shm_perm.mode & SHM_DEST)
966                 shm_destroy(ns, shp);
967         else
968                 shm_unlock(shp);
969         mutex_unlock(&shm_ids(ns).mutex);
970
971 out:
972         return err;
973
974 out_unlock:
975         shm_unlock(shp);
976         goto out;
977
978 out_free:
979         kfree(sfd);
980 out_put_path:
981         dput(path.dentry);
982         mntput(path.mnt);
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->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