ARM: tegra3: remove <board>-throttle_list_init functions
[linux-2.6.git] / ipc / shm.c
1 /*
2  * linux/ipc/shm.c
3  * Copyright (C) 1992, 1993 Krishna Balasubramanian
4  *       Many improvements/fixes by Bruno Haible.
5  * Replaced `struct shm_desc' by `struct vm_area_struct', July 1994.
6  * Fixed the shm swap deallocation (shm_unuse()), August 1998 Andrea Arcangeli.
7  *
8  * /proc/sysvipc/shm support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
9  * BIGMEM support, Andrea Arcangeli <andrea@suse.de>
10  * SMP thread shm, Jean-Luc Boyard <jean-luc.boyard@siemens.fr>
11  * HIGHMEM support, Ingo Molnar <mingo@redhat.com>
12  * Make shmmax, shmall, shmmni sysctl'able, Christoph Rohland <cr@sap.com>
13  * Shared /dev/zero support, Kanoj Sarcar <kanoj@sgi.com>
14  * Move the mm functionality over to mm/shmem.c, Christoph Rohland <cr@sap.com>
15  *
16  * support for audit of ipc object properties and permission changes
17  * Dustin Kirkland <dustin.kirkland@us.ibm.com>
18  *
19  * namespaces support
20  * OpenVZ, SWsoft Inc.
21  * Pavel Emelianov <xemul@openvz.org>
22  */
23
24 #include <linux/slab.h>
25 #include <linux/mm.h>
26 #include <linux/hugetlb.h>
27 #include <linux/shm.h>
28 #include <linux/init.h>
29 #include <linux/file.h>
30 #include <linux/mman.h>
31 #include <linux/shmem_fs.h>
32 #include <linux/security.h>
33 #include <linux/syscalls.h>
34 #include <linux/audit.h>
35 #include <linux/capability.h>
36 #include <linux/ptrace.h>
37 #include <linux/seq_file.h>
38 #include <linux/rwsem.h>
39 #include <linux/nsproxy.h>
40 #include <linux/mount.h>
41 #include <linux/ipc_namespace.h>
42
43 #include <asm/uaccess.h>
44
45 #include "util.h"
46
47 struct shm_file_data {
48         int id;
49         struct ipc_namespace *ns;
50         struct file *file;
51         const struct vm_operations_struct *vm_ops;
52 };
53
54 #define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data))
55
56 static const struct file_operations shm_file_operations;
57 static const struct vm_operations_struct shm_vm_ops;
58
59 #define shm_ids(ns)     ((ns)->ids[IPC_SHM_IDS])
60
61 #define shm_unlock(shp)                 \
62         ipc_unlock(&(shp)->shm_perm)
63
64 static int newseg(struct ipc_namespace *, struct ipc_params *);
65 static void shm_open(struct vm_area_struct *vma);
66 static void shm_close(struct vm_area_struct *vma);
67 static void shm_destroy (struct ipc_namespace *ns, struct shmid_kernel *shp);
68 #ifdef CONFIG_PROC_FS
69 static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
70 #endif
71
72 void shm_init_ns(struct ipc_namespace *ns)
73 {
74         ns->shm_ctlmax = SHMMAX;
75         ns->shm_ctlall = SHMALL;
76         ns->shm_ctlmni = SHMMNI;
77         ns->shm_rmid_forced = 0;
78         ns->shm_tot = 0;
79         ipc_init_ids(&shm_ids(ns));
80 }
81
82 /*
83  * Called with shm_ids.rw_mutex (writer) and the shp structure locked.
84  * Only shm_ids.rw_mutex remains locked on exit.
85  */
86 static void do_shm_rmid(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
87 {
88         struct shmid_kernel *shp;
89         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
90
91         if (shp->shm_nattch){
92                 shp->shm_perm.mode |= SHM_DEST;
93                 /* Do not find it any more */
94                 shp->shm_perm.key = IPC_PRIVATE;
95                 shm_unlock(shp);
96         } else
97                 shm_destroy(ns, shp);
98 }
99
100 #ifdef CONFIG_IPC_NS
101 void shm_exit_ns(struct ipc_namespace *ns)
102 {
103         free_ipcs(ns, &shm_ids(ns), do_shm_rmid);
104         idr_destroy(&ns->ids[IPC_SHM_IDS].ipcs_idr);
105 }
106 #endif
107
108 static int __init ipc_ns_init(void)
109 {
110         shm_init_ns(&init_ipc_ns);
111         return 0;
112 }
113
114 pure_initcall(ipc_ns_init);
115
116 void __init shm_init (void)
117 {
118         ipc_init_proc_interface("sysvipc/shm",
119 #if BITS_PER_LONG <= 32
120                                 "       key      shmid perms       size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime        rss       swap\n",
121 #else
122                                 "       key      shmid perms                  size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime                   rss                  swap\n",
123 #endif
124                                 IPC_SHM_IDS, sysvipc_shm_proc_show);
125 }
126
127 /*
128  * shm_lock_(check_) routines are called in the paths where the rw_mutex
129  * is not necessarily held.
130  */
131 static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
132 {
133         struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id);
134
135         if (IS_ERR(ipcp))
136                 return (struct shmid_kernel *)ipcp;
137
138         return container_of(ipcp, struct shmid_kernel, shm_perm);
139 }
140
141 static inline void shm_lock_by_ptr(struct shmid_kernel *ipcp)
142 {
143         rcu_read_lock();
144         spin_lock(&ipcp->shm_perm.lock);
145 }
146
147 static inline struct shmid_kernel *shm_lock_check(struct ipc_namespace *ns,
148                                                 int id)
149 {
150         struct kern_ipc_perm *ipcp = ipc_lock_check(&shm_ids(ns), id);
151
152         if (IS_ERR(ipcp))
153                 return (struct shmid_kernel *)ipcp;
154
155         return container_of(ipcp, struct shmid_kernel, shm_perm);
156 }
157
158 static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
159 {
160         ipc_rmid(&shm_ids(ns), &s->shm_perm);
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(IS_ERR(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  * @ns: namespace
183  * @shp: struct to free
184  *
185  * It has to be called with shp and shm_ids.rw_mutex (writer) locked,
186  * but returns with shp unlocked and freed.
187  */
188 static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
189 {
190         ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
191         shm_rmid(ns, shp);
192         shm_unlock(shp);
193         if (!is_file_hugepages(shp->shm_file))
194                 shmem_lock(shp->shm_file, 0, shp->mlock_user);
195         else if (shp->mlock_user)
196                 user_shm_unlock(shp->shm_file->f_path.dentry->d_inode->i_size,
197                                                 shp->mlock_user);
198         fput (shp->shm_file);
199         security_shm_free(shp);
200         ipc_rcu_putref(shp);
201 }
202
203 /*
204  * shm_may_destroy - identifies whether shm segment should be destroyed now
205  *
206  * Returns true if and only if there are no active users of the segment and
207  * one of the following is true:
208  *
209  * 1) shmctl(id, IPC_RMID, NULL) was called for this shp
210  *
211  * 2) sysctl kernel.shm_rmid_forced is set to 1.
212  */
213 static bool shm_may_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
214 {
215         return (shp->shm_nattch == 0) &&
216                (ns->shm_rmid_forced ||
217                 (shp->shm_perm.mode & SHM_DEST));
218 }
219
220 /*
221  * remove the attach descriptor vma.
222  * free memory for segment if it is marked destroyed.
223  * The descriptor has already been removed from the current->mm->mmap list
224  * and will later be kfree()d.
225  */
226 static void shm_close(struct vm_area_struct *vma)
227 {
228         struct file * file = vma->vm_file;
229         struct shm_file_data *sfd = shm_file_data(file);
230         struct shmid_kernel *shp;
231         struct ipc_namespace *ns = sfd->ns;
232
233         down_write(&shm_ids(ns).rw_mutex);
234         /* remove from the list of attaches of the shm segment */
235         shp = shm_lock(ns, sfd->id);
236         BUG_ON(IS_ERR(shp));
237         shp->shm_lprid = task_tgid_vnr(current);
238         shp->shm_dtim = get_seconds();
239         shp->shm_nattch--;
240         if (shm_may_destroy(ns, shp))
241                 shm_destroy(ns, shp);
242         else
243                 shm_unlock(shp);
244         up_write(&shm_ids(ns).rw_mutex);
245 }
246
247 /* Called with ns->shm_ids(ns).rw_mutex locked */
248 static int shm_try_destroy_current(int id, void *p, void *data)
249 {
250         struct ipc_namespace *ns = data;
251         struct kern_ipc_perm *ipcp = p;
252         struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
253
254         if (shp->shm_creator != current)
255                 return 0;
256
257         /*
258          * Mark it as orphaned to destroy the segment when
259          * kernel.shm_rmid_forced is changed.
260          * It is noop if the following shm_may_destroy() returns true.
261          */
262         shp->shm_creator = NULL;
263
264         /*
265          * Don't even try to destroy it.  If shm_rmid_forced=0 and IPC_RMID
266          * is not set, it shouldn't be deleted here.
267          */
268         if (!ns->shm_rmid_forced)
269                 return 0;
270
271         if (shm_may_destroy(ns, shp)) {
272                 shm_lock_by_ptr(shp);
273                 shm_destroy(ns, shp);
274         }
275         return 0;
276 }
277
278 /* Called with ns->shm_ids(ns).rw_mutex locked */
279 static int shm_try_destroy_orphaned(int id, void *p, void *data)
280 {
281         struct ipc_namespace *ns = data;
282         struct kern_ipc_perm *ipcp = p;
283         struct shmid_kernel *shp = container_of(ipcp, struct shmid_kernel, shm_perm);
284
285         /*
286          * We want to destroy segments without users and with already
287          * exit'ed originating process.
288          *
289          * As shp->* are changed under rw_mutex, it's safe to skip shp locking.
290          */
291         if (shp->shm_creator != NULL)
292                 return 0;
293
294         if (shm_may_destroy(ns, shp)) {
295                 shm_lock_by_ptr(shp);
296                 shm_destroy(ns, shp);
297         }
298         return 0;
299 }
300
301 void shm_destroy_orphaned(struct ipc_namespace *ns)
302 {
303         down_write(&shm_ids(ns).rw_mutex);
304         if (shm_ids(ns).in_use)
305                 idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_orphaned, ns);
306         up_write(&shm_ids(ns).rw_mutex);
307 }
308
309
310 void exit_shm(struct task_struct *task)
311 {
312         struct ipc_namespace *ns = task->nsproxy->ipc_ns;
313
314         if (shm_ids(ns).in_use == 0)
315                 return;
316
317         /* Destroy all already created segments, but not mapped yet */
318         down_write(&shm_ids(ns).rw_mutex);
319         if (shm_ids(ns).in_use)
320                 idr_for_each(&shm_ids(ns).ipcs_idr, &shm_try_destroy_current, ns);
321         up_write(&shm_ids(ns).rw_mutex);
322 }
323
324 static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
325 {
326         struct file *file = vma->vm_file;
327         struct shm_file_data *sfd = shm_file_data(file);
328
329         return sfd->vm_ops->fault(vma, vmf);
330 }
331
332 #ifdef CONFIG_NUMA
333 static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
334 {
335         struct file *file = vma->vm_file;
336         struct shm_file_data *sfd = shm_file_data(file);
337         int err = 0;
338         if (sfd->vm_ops->set_policy)
339                 err = sfd->vm_ops->set_policy(vma, new);
340         return err;
341 }
342
343 static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
344                                         unsigned long addr)
345 {
346         struct file *file = vma->vm_file;
347         struct shm_file_data *sfd = shm_file_data(file);
348         struct mempolicy *pol = NULL;
349
350         if (sfd->vm_ops->get_policy)
351                 pol = sfd->vm_ops->get_policy(vma, addr);
352         else if (vma->vm_policy)
353                 pol = vma->vm_policy;
354
355         return pol;
356 }
357 #endif
358
359 static int shm_mmap(struct file * file, struct vm_area_struct * vma)
360 {
361         struct shm_file_data *sfd = shm_file_data(file);
362         int ret;
363
364         ret = sfd->file->f_op->mmap(sfd->file, vma);
365         if (ret != 0)
366                 return ret;
367         sfd->vm_ops = vma->vm_ops;
368 #ifdef CONFIG_MMU
369         BUG_ON(!sfd->vm_ops->fault);
370 #endif
371         vma->vm_ops = &shm_vm_ops;
372         shm_open(vma);
373
374         return ret;
375 }
376
377 static int shm_release(struct inode *ino, struct file *file)
378 {
379         struct shm_file_data *sfd = shm_file_data(file);
380
381         put_ipc_ns(sfd->ns);
382         shm_file_data(file) = NULL;
383         kfree(sfd);
384         return 0;
385 }
386
387 static int shm_fsync(struct file *file, loff_t start, loff_t end, int datasync)
388 {
389         struct shm_file_data *sfd = shm_file_data(file);
390
391         if (!sfd->file->f_op->fsync)
392                 return -EINVAL;
393         return sfd->file->f_op->fsync(sfd->file, start, end, datasync);
394 }
395
396 static unsigned long shm_get_unmapped_area(struct file *file,
397         unsigned long addr, unsigned long len, unsigned long pgoff,
398         unsigned long flags)
399 {
400         struct shm_file_data *sfd = shm_file_data(file);
401         return sfd->file->f_op->get_unmapped_area(sfd->file, addr, len,
402                                                 pgoff, flags);
403 }
404
405 static const struct file_operations shm_file_operations = {
406         .mmap           = shm_mmap,
407         .fsync          = shm_fsync,
408         .release        = shm_release,
409 #ifndef CONFIG_MMU
410         .get_unmapped_area      = shm_get_unmapped_area,
411 #endif
412         .llseek         = noop_llseek,
413 };
414
415 static const struct file_operations shm_file_operations_huge = {
416         .mmap           = shm_mmap,
417         .fsync          = shm_fsync,
418         .release        = shm_release,
419         .get_unmapped_area      = shm_get_unmapped_area,
420         .llseek         = noop_llseek,
421 };
422
423 int is_file_shm_hugepages(struct file *file)
424 {
425         return file->f_op == &shm_file_operations_huge;
426 }
427
428 static const struct vm_operations_struct shm_vm_ops = {
429         .open   = shm_open,     /* callback for a new vm-area open */
430         .close  = shm_close,    /* callback for when the vm-area is released */
431         .fault  = shm_fault,
432 #if defined(CONFIG_NUMA)
433         .set_policy = shm_set_policy,
434         .get_policy = shm_get_policy,
435 #endif
436 };
437
438 /**
439  * newseg - Create a new shared memory segment
440  * @ns: namespace
441  * @params: ptr to the structure that contains key, size and shmflg
442  *
443  * Called with shm_ids.rw_mutex held as a writer.
444  */
445
446 static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
447 {
448         key_t key = params->key;
449         int shmflg = params->flg;
450         size_t size = params->u.size;
451         int error;
452         struct shmid_kernel *shp;
453         int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
454         struct file * file;
455         char name[13];
456         int id;
457         vm_flags_t acctflag = 0;
458
459         if (size < SHMMIN || size > ns->shm_ctlmax)
460                 return -EINVAL;
461
462         if (ns->shm_tot + numpages > ns->shm_ctlall)
463                 return -ENOSPC;
464
465         shp = ipc_rcu_alloc(sizeof(*shp));
466         if (!shp)
467                 return -ENOMEM;
468
469         shp->shm_perm.key = key;
470         shp->shm_perm.mode = (shmflg & S_IRWXUGO);
471         shp->mlock_user = NULL;
472
473         shp->shm_perm.security = NULL;
474         error = security_shm_alloc(shp);
475         if (error) {
476                 ipc_rcu_putref(shp);
477                 return error;
478         }
479
480         sprintf (name, "SYSV%08x", key);
481         if (shmflg & SHM_HUGETLB) {
482                 /* hugetlb_file_setup applies strict accounting */
483                 if (shmflg & SHM_NORESERVE)
484                         acctflag = VM_NORESERVE;
485                 file = hugetlb_file_setup(name, 0, size, acctflag,
486                                         &shp->mlock_user, HUGETLB_SHMFS_INODE);
487         } else {
488                 /*
489                  * Do not allow no accounting for OVERCOMMIT_NEVER, even
490                  * if it's asked for.
491                  */
492                 if  ((shmflg & SHM_NORESERVE) &&
493                                 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
494                         acctflag = VM_NORESERVE;
495                 file = shmem_file_setup(name, size, acctflag);
496         }
497         error = PTR_ERR(file);
498         if (IS_ERR(file))
499                 goto no_file;
500
501         id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
502         if (id < 0) {
503                 error = id;
504                 goto no_id;
505         }
506
507         shp->shm_cprid = task_tgid_vnr(current);
508         shp->shm_lprid = 0;
509         shp->shm_atim = shp->shm_dtim = 0;
510         shp->shm_ctim = get_seconds();
511         shp->shm_segsz = size;
512         shp->shm_nattch = 0;
513         shp->shm_file = file;
514         shp->shm_creator = current;
515         /*
516          * shmid gets reported as "inode#" in /proc/pid/maps.
517          * proc-ps tools use this. Changing this will break them.
518          */
519         file->f_dentry->d_inode->i_ino = shp->shm_perm.id;
520
521         ns->shm_tot += numpages;
522         error = shp->shm_perm.id;
523         shm_unlock(shp);
524         return error;
525
526 no_id:
527         if (is_file_hugepages(file) && shp->mlock_user)
528                 user_shm_unlock(size, shp->mlock_user);
529         fput(file);
530 no_file:
531         security_shm_free(shp);
532         ipc_rcu_putref(shp);
533         return error;
534 }
535
536 /*
537  * Called with shm_ids.rw_mutex and ipcp locked.
538  */
539 static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)
540 {
541         struct shmid_kernel *shp;
542
543         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
544         return security_shm_associate(shp, shmflg);
545 }
546
547 /*
548  * Called with shm_ids.rw_mutex and ipcp locked.
549  */
550 static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
551                                 struct ipc_params *params)
552 {
553         struct shmid_kernel *shp;
554
555         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
556         if (shp->shm_segsz < params->u.size)
557                 return -EINVAL;
558
559         return 0;
560 }
561
562 SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg)
563 {
564         struct ipc_namespace *ns;
565         struct ipc_ops shm_ops;
566         struct ipc_params shm_params;
567
568         ns = current->nsproxy->ipc_ns;
569
570         shm_ops.getnew = newseg;
571         shm_ops.associate = shm_security;
572         shm_ops.more_checks = shm_more_checks;
573
574         shm_params.key = key;
575         shm_params.flg = shmflg;
576         shm_params.u.size = size;
577
578         return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
579 }
580
581 static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
582 {
583         switch(version) {
584         case IPC_64:
585                 return copy_to_user(buf, in, sizeof(*in));
586         case IPC_OLD:
587             {
588                 struct shmid_ds out;
589
590                 memset(&out, 0, sizeof(out));
591                 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
592                 out.shm_segsz   = in->shm_segsz;
593                 out.shm_atime   = in->shm_atime;
594                 out.shm_dtime   = in->shm_dtime;
595                 out.shm_ctime   = in->shm_ctime;
596                 out.shm_cpid    = in->shm_cpid;
597                 out.shm_lpid    = in->shm_lpid;
598                 out.shm_nattch  = in->shm_nattch;
599
600                 return copy_to_user(buf, &out, sizeof(out));
601             }
602         default:
603                 return -EINVAL;
604         }
605 }
606
607 static inline unsigned long
608 copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version)
609 {
610         switch(version) {
611         case IPC_64:
612                 if (copy_from_user(out, buf, sizeof(*out)))
613                         return -EFAULT;
614                 return 0;
615         case IPC_OLD:
616             {
617                 struct shmid_ds tbuf_old;
618
619                 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
620                         return -EFAULT;
621
622                 out->shm_perm.uid       = tbuf_old.shm_perm.uid;
623                 out->shm_perm.gid       = tbuf_old.shm_perm.gid;
624                 out->shm_perm.mode      = tbuf_old.shm_perm.mode;
625
626                 return 0;
627             }
628         default:
629                 return -EINVAL;
630         }
631 }
632
633 static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
634 {
635         switch(version) {
636         case IPC_64:
637                 return copy_to_user(buf, in, sizeof(*in));
638         case IPC_OLD:
639             {
640                 struct shminfo out;
641
642                 if(in->shmmax > INT_MAX)
643                         out.shmmax = INT_MAX;
644                 else
645                         out.shmmax = (int)in->shmmax;
646
647                 out.shmmin      = in->shmmin;
648                 out.shmmni      = in->shmmni;
649                 out.shmseg      = in->shmseg;
650                 out.shmall      = in->shmall; 
651
652                 return copy_to_user(buf, &out, sizeof(out));
653             }
654         default:
655                 return -EINVAL;
656         }
657 }
658
659 /*
660  * Calculate and add used RSS and swap pages of a shm.
661  * Called with shm_ids.rw_mutex held as a reader
662  */
663 static void shm_add_rss_swap(struct shmid_kernel *shp,
664         unsigned long *rss_add, unsigned long *swp_add)
665 {
666         struct inode *inode;
667
668         inode = shp->shm_file->f_path.dentry->d_inode;
669
670         if (is_file_hugepages(shp->shm_file)) {
671                 struct address_space *mapping = inode->i_mapping;
672                 struct hstate *h = hstate_file(shp->shm_file);
673                 *rss_add += pages_per_huge_page(h) * mapping->nrpages;
674         } else {
675 #ifdef CONFIG_SHMEM
676                 struct shmem_inode_info *info = SHMEM_I(inode);
677                 spin_lock(&info->lock);
678                 *rss_add += inode->i_mapping->nrpages;
679                 *swp_add += info->swapped;
680                 spin_unlock(&info->lock);
681 #else
682                 *rss_add += inode->i_mapping->nrpages;
683 #endif
684         }
685 }
686
687 /*
688  * Called with shm_ids.rw_mutex held as a reader
689  */
690 static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
691                 unsigned long *swp)
692 {
693         int next_id;
694         int total, in_use;
695
696         *rss = 0;
697         *swp = 0;
698
699         in_use = shm_ids(ns).in_use;
700
701         for (total = 0, next_id = 0; total < in_use; next_id++) {
702                 struct kern_ipc_perm *ipc;
703                 struct shmid_kernel *shp;
704
705                 ipc = idr_find(&shm_ids(ns).ipcs_idr, next_id);
706                 if (ipc == NULL)
707                         continue;
708                 shp = container_of(ipc, struct shmid_kernel, shm_perm);
709
710                 shm_add_rss_swap(shp, rss, swp);
711
712                 total++;
713         }
714 }
715
716 /*
717  * This function handles some shmctl commands which require the rw_mutex
718  * to be held in write mode.
719  * NOTE: no locks must be held, the rw_mutex is taken inside this function.
720  */
721 static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
722                        struct shmid_ds __user *buf, int version)
723 {
724         struct kern_ipc_perm *ipcp;
725         struct shmid64_ds shmid64;
726         struct shmid_kernel *shp;
727         int err;
728
729         if (cmd == IPC_SET) {
730                 if (copy_shmid_from_user(&shmid64, buf, version))
731                         return -EFAULT;
732         }
733
734         ipcp = ipcctl_pre_down(ns, &shm_ids(ns), shmid, cmd,
735                                &shmid64.shm_perm, 0);
736         if (IS_ERR(ipcp))
737                 return PTR_ERR(ipcp);
738
739         shp = container_of(ipcp, struct shmid_kernel, shm_perm);
740
741         err = security_shm_shmctl(shp, cmd);
742         if (err)
743                 goto out_unlock;
744         switch (cmd) {
745         case IPC_RMID:
746                 do_shm_rmid(ns, ipcp);
747                 goto out_up;
748         case IPC_SET:
749                 ipc_update_perm(&shmid64.shm_perm, ipcp);
750                 shp->shm_ctim = get_seconds();
751                 break;
752         default:
753                 err = -EINVAL;
754         }
755 out_unlock:
756         shm_unlock(shp);
757 out_up:
758         up_write(&shm_ids(ns).rw_mutex);
759         return err;
760 }
761
762 SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
763 {
764         struct shmid_kernel *shp;
765         int err, version;
766         struct ipc_namespace *ns;
767
768         if (cmd < 0 || shmid < 0) {
769                 err = -EINVAL;
770                 goto out;
771         }
772
773         version = ipc_parse_version(&cmd);
774         ns = current->nsproxy->ipc_ns;
775
776         switch (cmd) { /* replace with proc interface ? */
777         case IPC_INFO:
778         {
779                 struct shminfo64 shminfo;
780
781                 err = security_shm_shmctl(NULL, cmd);
782                 if (err)
783                         return err;
784
785                 memset(&shminfo, 0, sizeof(shminfo));
786                 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
787                 shminfo.shmmax = ns->shm_ctlmax;
788                 shminfo.shmall = ns->shm_ctlall;
789
790                 shminfo.shmmin = SHMMIN;
791                 if(copy_shminfo_to_user (buf, &shminfo, version))
792                         return -EFAULT;
793
794                 down_read(&shm_ids(ns).rw_mutex);
795                 err = ipc_get_maxid(&shm_ids(ns));
796                 up_read(&shm_ids(ns).rw_mutex);
797
798                 if(err<0)
799                         err = 0;
800                 goto out;
801         }
802         case SHM_INFO:
803         {
804                 struct shm_info shm_info;
805
806                 err = security_shm_shmctl(NULL, cmd);
807                 if (err)
808                         return err;
809
810                 memset(&shm_info, 0, sizeof(shm_info));
811                 down_read(&shm_ids(ns).rw_mutex);
812                 shm_info.used_ids = shm_ids(ns).in_use;
813                 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
814                 shm_info.shm_tot = ns->shm_tot;
815                 shm_info.swap_attempts = 0;
816                 shm_info.swap_successes = 0;
817                 err = ipc_get_maxid(&shm_ids(ns));
818                 up_read(&shm_ids(ns).rw_mutex);
819                 if (copy_to_user(buf, &shm_info, sizeof(shm_info))) {
820                         err = -EFAULT;
821                         goto out;
822                 }
823
824                 err = err < 0 ? 0 : err;
825                 goto out;
826         }
827         case SHM_STAT:
828         case IPC_STAT:
829         {
830                 struct shmid64_ds tbuf;
831                 int result;
832
833                 if (cmd == SHM_STAT) {
834                         shp = shm_lock(ns, shmid);
835                         if (IS_ERR(shp)) {
836                                 err = PTR_ERR(shp);
837                                 goto out;
838                         }
839                         result = shp->shm_perm.id;
840                 } else {
841                         shp = shm_lock_check(ns, shmid);
842                         if (IS_ERR(shp)) {
843                                 err = PTR_ERR(shp);
844                                 goto out;
845                         }
846                         result = 0;
847                 }
848                 err = -EACCES;
849                 if (ipcperms(ns, &shp->shm_perm, S_IRUGO))
850                         goto out_unlock;
851                 err = security_shm_shmctl(shp, cmd);
852                 if (err)
853                         goto out_unlock;
854                 memset(&tbuf, 0, sizeof(tbuf));
855                 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
856                 tbuf.shm_segsz  = shp->shm_segsz;
857                 tbuf.shm_atime  = shp->shm_atim;
858                 tbuf.shm_dtime  = shp->shm_dtim;
859                 tbuf.shm_ctime  = shp->shm_ctim;
860                 tbuf.shm_cpid   = shp->shm_cprid;
861                 tbuf.shm_lpid   = shp->shm_lprid;
862                 tbuf.shm_nattch = shp->shm_nattch;
863                 shm_unlock(shp);
864                 if(copy_shmid_to_user (buf, &tbuf, version))
865                         err = -EFAULT;
866                 else
867                         err = result;
868                 goto out;
869         }
870         case SHM_LOCK:
871         case SHM_UNLOCK:
872         {
873                 struct file *shm_file;
874
875                 shp = shm_lock_check(ns, shmid);
876                 if (IS_ERR(shp)) {
877                         err = PTR_ERR(shp);
878                         goto out;
879                 }
880
881                 audit_ipc_obj(&(shp->shm_perm));
882
883                 if (!ns_capable(ns->user_ns, CAP_IPC_LOCK)) {
884                         uid_t euid = current_euid();
885                         err = -EPERM;
886                         if (euid != shp->shm_perm.uid &&
887                             euid != shp->shm_perm.cuid)
888                                 goto out_unlock;
889                         if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK))
890                                 goto out_unlock;
891                 }
892
893                 err = security_shm_shmctl(shp, cmd);
894                 if (err)
895                         goto out_unlock;
896
897                 shm_file = shp->shm_file;
898                 if (is_file_hugepages(shm_file))
899                         goto out_unlock;
900
901                 if (cmd == SHM_LOCK) {
902                         struct user_struct *user = current_user();
903                         err = shmem_lock(shm_file, 1, user);
904                         if (!err && !(shp->shm_perm.mode & SHM_LOCKED)) {
905                                 shp->shm_perm.mode |= SHM_LOCKED;
906                                 shp->mlock_user = user;
907                         }
908                         goto out_unlock;
909                 }
910
911                 /* SHM_UNLOCK */
912                 if (!(shp->shm_perm.mode & SHM_LOCKED))
913                         goto out_unlock;
914                 shmem_lock(shm_file, 0, shp->mlock_user);
915                 shp->shm_perm.mode &= ~SHM_LOCKED;
916                 shp->mlock_user = NULL;
917                 get_file(shm_file);
918                 shm_unlock(shp);
919                 shmem_unlock_mapping(shm_file->f_mapping);
920                 fput(shm_file);
921                 goto out;
922         }
923         case IPC_RMID:
924         case IPC_SET:
925                 err = shmctl_down(ns, shmid, cmd, buf, version);
926                 return err;
927         default:
928                 return -EINVAL;
929         }
930
931 out_unlock:
932         shm_unlock(shp);
933 out:
934         return err;
935 }
936
937 /*
938  * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
939  *
940  * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
941  * "raddr" thing points to kernel space, and there has to be a wrapper around
942  * this.
943  */
944 long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
945 {
946         struct shmid_kernel *shp;
947         unsigned long addr;
948         unsigned long size;
949         struct file * file;
950         int    err;
951         unsigned long flags;
952         unsigned long prot;
953         int acc_mode;
954         unsigned long user_addr;
955         struct ipc_namespace *ns;
956         struct shm_file_data *sfd;
957         struct path path;
958         fmode_t f_mode;
959
960         err = -EINVAL;
961         if (shmid < 0)
962                 goto out;
963         else if ((addr = (ulong)shmaddr)) {
964                 if (addr & (SHMLBA-1)) {
965                         if (shmflg & SHM_RND)
966                                 addr &= ~(SHMLBA-1);       /* round down */
967                         else
968 #ifndef __ARCH_FORCE_SHMLBA
969                                 if (addr & ~PAGE_MASK)
970 #endif
971                                         goto out;
972                 }
973                 flags = MAP_SHARED | MAP_FIXED;
974         } else {
975                 if ((shmflg & SHM_REMAP))
976                         goto out;
977
978                 flags = MAP_SHARED;
979         }
980
981         if (shmflg & SHM_RDONLY) {
982                 prot = PROT_READ;
983                 acc_mode = S_IRUGO;
984                 f_mode = FMODE_READ;
985         } else {
986                 prot = PROT_READ | PROT_WRITE;
987                 acc_mode = S_IRUGO | S_IWUGO;
988                 f_mode = FMODE_READ | FMODE_WRITE;
989         }
990         if (shmflg & SHM_EXEC) {
991                 prot |= PROT_EXEC;
992                 acc_mode |= S_IXUGO;
993         }
994
995         /*
996          * We cannot rely on the fs check since SYSV IPC does have an
997          * additional creator id...
998          */
999         ns = current->nsproxy->ipc_ns;
1000         shp = shm_lock_check(ns, shmid);
1001         if (IS_ERR(shp)) {
1002                 err = PTR_ERR(shp);
1003                 goto out;
1004         }
1005
1006         err = -EACCES;
1007         if (ipcperms(ns, &shp->shm_perm, acc_mode))
1008                 goto out_unlock;
1009
1010         err = security_shm_shmat(shp, shmaddr, shmflg);
1011         if (err)
1012                 goto out_unlock;
1013
1014         path = shp->shm_file->f_path;
1015         path_get(&path);
1016         shp->shm_nattch++;
1017         size = i_size_read(path.dentry->d_inode);
1018         shm_unlock(shp);
1019
1020         err = -ENOMEM;
1021         sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
1022         if (!sfd)
1023                 goto out_put_dentry;
1024
1025         file = alloc_file(&path, f_mode,
1026                           is_file_hugepages(shp->shm_file) ?
1027                                 &shm_file_operations_huge :
1028                                 &shm_file_operations);
1029         if (!file)
1030                 goto out_free;
1031
1032         file->private_data = sfd;
1033         file->f_mapping = shp->shm_file->f_mapping;
1034         sfd->id = shp->shm_perm.id;
1035         sfd->ns = get_ipc_ns(ns);
1036         sfd->file = shp->shm_file;
1037         sfd->vm_ops = NULL;
1038
1039         down_write(&current->mm->mmap_sem);
1040         if (addr && !(shmflg & SHM_REMAP)) {
1041                 err = -EINVAL;
1042                 if (find_vma_intersection(current->mm, addr, addr + size))
1043                         goto invalid;
1044                 /*
1045                  * If shm segment goes below stack, make sure there is some
1046                  * space left for the stack to grow (at least 4 pages).
1047                  */
1048                 if (addr < current->mm->start_stack &&
1049                     addr > current->mm->start_stack - size - PAGE_SIZE * 5)
1050                         goto invalid;
1051         }
1052                 
1053         user_addr = do_mmap (file, addr, size, prot, flags, 0);
1054         *raddr = user_addr;
1055         err = 0;
1056         if (IS_ERR_VALUE(user_addr))
1057                 err = (long)user_addr;
1058 invalid:
1059         up_write(&current->mm->mmap_sem);
1060
1061         fput(file);
1062
1063 out_nattch:
1064         down_write(&shm_ids(ns).rw_mutex);
1065         shp = shm_lock(ns, shmid);
1066         BUG_ON(IS_ERR(shp));
1067         shp->shm_nattch--;
1068         if (shm_may_destroy(ns, shp))
1069                 shm_destroy(ns, shp);
1070         else
1071                 shm_unlock(shp);
1072         up_write(&shm_ids(ns).rw_mutex);
1073
1074 out:
1075         return err;
1076
1077 out_unlock:
1078         shm_unlock(shp);
1079         goto out;
1080
1081 out_free:
1082         kfree(sfd);
1083 out_put_dentry:
1084         path_put(&path);
1085         goto out_nattch;
1086 }
1087
1088 SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg)
1089 {
1090         unsigned long ret;
1091         long err;
1092
1093         err = do_shmat(shmid, shmaddr, shmflg, &ret);
1094         if (err)
1095                 return err;
1096         force_successful_syscall_return();
1097         return (long)ret;
1098 }
1099
1100 /*
1101  * detach and kill segment if marked destroyed.
1102  * The work is done in shm_close.
1103  */
1104 SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
1105 {
1106         struct mm_struct *mm = current->mm;
1107         struct vm_area_struct *vma;
1108         unsigned long addr = (unsigned long)shmaddr;
1109         int retval = -EINVAL;
1110 #ifdef CONFIG_MMU
1111         loff_t size = 0;
1112         struct vm_area_struct *next;
1113 #endif
1114
1115         if (addr & ~PAGE_MASK)
1116                 return retval;
1117
1118         down_write(&mm->mmap_sem);
1119
1120         /*
1121          * This function tries to be smart and unmap shm segments that
1122          * were modified by partial mlock or munmap calls:
1123          * - It first determines the size of the shm segment that should be
1124          *   unmapped: It searches for a vma that is backed by shm and that
1125          *   started at address shmaddr. It records it's size and then unmaps
1126          *   it.
1127          * - Then it unmaps all shm vmas that started at shmaddr and that
1128          *   are within the initially determined size.
1129          * Errors from do_munmap are ignored: the function only fails if
1130          * it's called with invalid parameters or if it's called to unmap
1131          * a part of a vma. Both calls in this function are for full vmas,
1132          * the parameters are directly copied from the vma itself and always
1133          * valid - therefore do_munmap cannot fail. (famous last words?)
1134          */
1135         /*
1136          * If it had been mremap()'d, the starting address would not
1137          * match the usual checks anyway. So assume all vma's are
1138          * above the starting address given.
1139          */
1140         vma = find_vma(mm, addr);
1141
1142 #ifdef CONFIG_MMU
1143         while (vma) {
1144                 next = vma->vm_next;
1145
1146                 /*
1147                  * Check if the starting address would match, i.e. it's
1148                  * a fragment created by mprotect() and/or munmap(), or it
1149                  * otherwise it starts at this address with no hassles.
1150                  */
1151                 if ((vma->vm_ops == &shm_vm_ops) &&
1152                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1153
1154
1155                         size = vma->vm_file->f_path.dentry->d_inode->i_size;
1156                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1157                         /*
1158                          * We discovered the size of the shm segment, so
1159                          * break out of here and fall through to the next
1160                          * loop that uses the size information to stop
1161                          * searching for matching vma's.
1162                          */
1163                         retval = 0;
1164                         vma = next;
1165                         break;
1166                 }
1167                 vma = next;
1168         }
1169
1170         /*
1171          * We need look no further than the maximum address a fragment
1172          * could possibly have landed at. Also cast things to loff_t to
1173          * prevent overflows and make comparisons vs. equal-width types.
1174          */
1175         size = PAGE_ALIGN(size);
1176         while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1177                 next = vma->vm_next;
1178
1179                 /* finding a matching vma now does not alter retval */
1180                 if ((vma->vm_ops == &shm_vm_ops) &&
1181                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1182
1183                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1184                 vma = next;
1185         }
1186
1187 #else /* CONFIG_MMU */
1188         /* under NOMMU conditions, the exact address to be destroyed must be
1189          * given */
1190         retval = -EINVAL;
1191         if (vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) {
1192                 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1193                 retval = 0;
1194         }
1195
1196 #endif
1197
1198         up_write(&mm->mmap_sem);
1199         return retval;
1200 }
1201
1202 #ifdef CONFIG_PROC_FS
1203 static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1204 {
1205         struct shmid_kernel *shp = it;
1206         unsigned long rss = 0, swp = 0;
1207
1208         shm_add_rss_swap(shp, &rss, &swp);
1209
1210 #if BITS_PER_LONG <= 32
1211 #define SIZE_SPEC "%10lu"
1212 #else
1213 #define SIZE_SPEC "%21lu"
1214 #endif
1215
1216         return seq_printf(s,
1217                           "%10d %10d  %4o " SIZE_SPEC " %5u %5u  "
1218                           "%5lu %5u %5u %5u %5u %10lu %10lu %10lu "
1219                           SIZE_SPEC " " SIZE_SPEC "\n",
1220                           shp->shm_perm.key,
1221                           shp->shm_perm.id,
1222                           shp->shm_perm.mode,
1223                           shp->shm_segsz,
1224                           shp->shm_cprid,
1225                           shp->shm_lprid,
1226                           shp->shm_nattch,
1227                           shp->shm_perm.uid,
1228                           shp->shm_perm.gid,
1229                           shp->shm_perm.cuid,
1230                           shp->shm_perm.cgid,
1231                           shp->shm_atim,
1232                           shp->shm_dtim,
1233                           shp->shm_ctim,
1234                           rss * PAGE_SIZE,
1235                           swp * PAGE_SIZE);
1236 }
1237 #endif