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