[ALSA] pci_find_device remove
[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  */
17
18 #include <linux/config.h>
19 #include <linux/slab.h>
20 #include <linux/mm.h>
21 #include <linux/hugetlb.h>
22 #include <linux/shm.h>
23 #include <linux/init.h>
24 #include <linux/file.h>
25 #include <linux/mman.h>
26 #include <linux/shmem_fs.h>
27 #include <linux/security.h>
28 #include <linux/syscalls.h>
29 #include <linux/audit.h>
30 #include <linux/ptrace.h>
31 #include <linux/seq_file.h>
32
33 #include <asm/uaccess.h>
34
35 #include "util.h"
36
37 #define shm_flags       shm_perm.mode
38
39 static struct file_operations shm_file_operations;
40 static struct vm_operations_struct shm_vm_ops;
41
42 static struct ipc_ids shm_ids;
43
44 #define shm_lock(id)    ((struct shmid_kernel*)ipc_lock(&shm_ids,id))
45 #define shm_unlock(shp) ipc_unlock(&(shp)->shm_perm)
46 #define shm_get(id)     ((struct shmid_kernel*)ipc_get(&shm_ids,id))
47 #define shm_buildid(id, seq) \
48         ipc_buildid(&shm_ids, id, seq)
49
50 static int newseg (key_t key, int shmflg, size_t size);
51 static void shm_open (struct vm_area_struct *shmd);
52 static void shm_close (struct vm_area_struct *shmd);
53 #ifdef CONFIG_PROC_FS
54 static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
55 #endif
56
57 size_t  shm_ctlmax = SHMMAX;
58 size_t  shm_ctlall = SHMALL;
59 int     shm_ctlmni = SHMMNI;
60
61 static int shm_tot; /* total number of shared memory pages */
62
63 void __init shm_init (void)
64 {
65         ipc_init_ids(&shm_ids, 1);
66         ipc_init_proc_interface("sysvipc/shm",
67                                 "       key      shmid perms       size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime\n",
68                                 &shm_ids,
69                                 sysvipc_shm_proc_show);
70 }
71
72 static inline int shm_checkid(struct shmid_kernel *s, int id)
73 {
74         if (ipc_checkid(&shm_ids,&s->shm_perm,id))
75                 return -EIDRM;
76         return 0;
77 }
78
79 static inline struct shmid_kernel *shm_rmid(int id)
80 {
81         return (struct shmid_kernel *)ipc_rmid(&shm_ids,id);
82 }
83
84 static inline int shm_addid(struct shmid_kernel *shp)
85 {
86         return ipc_addid(&shm_ids, &shp->shm_perm, shm_ctlmni);
87 }
88
89
90
91 static inline void shm_inc (int id) {
92         struct shmid_kernel *shp;
93
94         if(!(shp = shm_lock(id)))
95                 BUG();
96         shp->shm_atim = get_seconds();
97         shp->shm_lprid = current->tgid;
98         shp->shm_nattch++;
99         shm_unlock(shp);
100 }
101
102 /* This is called by fork, once for every shm attach. */
103 static void shm_open (struct vm_area_struct *shmd)
104 {
105         shm_inc (shmd->vm_file->f_dentry->d_inode->i_ino);
106 }
107
108 /*
109  * shm_destroy - free the struct shmid_kernel
110  *
111  * @shp: struct to free
112  *
113  * It has to be called with shp and shm_ids.sem locked,
114  * but returns with shp unlocked and freed.
115  */
116 static void shm_destroy (struct shmid_kernel *shp)
117 {
118         shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
119         shm_rmid (shp->id);
120         shm_unlock(shp);
121         if (!is_file_hugepages(shp->shm_file))
122                 shmem_lock(shp->shm_file, 0, shp->mlock_user);
123         else
124                 user_shm_unlock(shp->shm_file->f_dentry->d_inode->i_size,
125                                                 shp->mlock_user);
126         fput (shp->shm_file);
127         security_shm_free(shp);
128         ipc_rcu_putref(shp);
129 }
130
131 /*
132  * remove the attach descriptor shmd.
133  * free memory for segment if it is marked destroyed.
134  * The descriptor has already been removed from the current->mm->mmap list
135  * and will later be kfree()d.
136  */
137 static void shm_close (struct vm_area_struct *shmd)
138 {
139         struct file * file = shmd->vm_file;
140         int id = file->f_dentry->d_inode->i_ino;
141         struct shmid_kernel *shp;
142
143         down (&shm_ids.sem);
144         /* remove from the list of attaches of the shm segment */
145         if(!(shp = shm_lock(id)))
146                 BUG();
147         shp->shm_lprid = current->tgid;
148         shp->shm_dtim = get_seconds();
149         shp->shm_nattch--;
150         if(shp->shm_nattch == 0 &&
151            shp->shm_flags & SHM_DEST)
152                 shm_destroy (shp);
153         else
154                 shm_unlock(shp);
155         up (&shm_ids.sem);
156 }
157
158 static int shm_mmap(struct file * file, struct vm_area_struct * vma)
159 {
160         file_accessed(file);
161         vma->vm_ops = &shm_vm_ops;
162         shm_inc(file->f_dentry->d_inode->i_ino);
163         return 0;
164 }
165
166 static struct file_operations shm_file_operations = {
167         .mmap   = shm_mmap
168 };
169
170 static struct vm_operations_struct shm_vm_ops = {
171         .open   = shm_open,     /* callback for a new vm-area open */
172         .close  = shm_close,    /* callback for when the vm-area is released */
173         .nopage = shmem_nopage,
174 #if defined(CONFIG_NUMA) && defined(CONFIG_SHMEM)
175         .set_policy = shmem_set_policy,
176         .get_policy = shmem_get_policy,
177 #endif
178 };
179
180 static int newseg (key_t key, int shmflg, size_t size)
181 {
182         int error;
183         struct shmid_kernel *shp;
184         int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
185         struct file * file;
186         char name[13];
187         int id;
188
189         if (size < SHMMIN || size > shm_ctlmax)
190                 return -EINVAL;
191
192         if (shm_tot + numpages >= shm_ctlall)
193                 return -ENOSPC;
194
195         shp = ipc_rcu_alloc(sizeof(*shp));
196         if (!shp)
197                 return -ENOMEM;
198
199         shp->shm_perm.key = key;
200         shp->shm_flags = (shmflg & S_IRWXUGO);
201         shp->mlock_user = NULL;
202
203         shp->shm_perm.security = NULL;
204         error = security_shm_alloc(shp);
205         if (error) {
206                 ipc_rcu_putref(shp);
207                 return error;
208         }
209
210         if (shmflg & SHM_HUGETLB) {
211                 /* hugetlb_zero_setup takes care of mlock user accounting */
212                 file = hugetlb_zero_setup(size);
213                 shp->mlock_user = current->user;
214         } else {
215                 sprintf (name, "SYSV%08x", key);
216                 file = shmem_file_setup(name, size, VM_ACCOUNT);
217         }
218         error = PTR_ERR(file);
219         if (IS_ERR(file))
220                 goto no_file;
221
222         error = -ENOSPC;
223         id = shm_addid(shp);
224         if(id == -1) 
225                 goto no_id;
226
227         shp->shm_cprid = current->tgid;
228         shp->shm_lprid = 0;
229         shp->shm_atim = shp->shm_dtim = 0;
230         shp->shm_ctim = get_seconds();
231         shp->shm_segsz = size;
232         shp->shm_nattch = 0;
233         shp->id = shm_buildid(id,shp->shm_perm.seq);
234         shp->shm_file = file;
235         file->f_dentry->d_inode->i_ino = shp->id;
236         if (shmflg & SHM_HUGETLB)
237                 set_file_hugepages(file);
238         else
239                 file->f_op = &shm_file_operations;
240         shm_tot += numpages;
241         shm_unlock(shp);
242         return shp->id;
243
244 no_id:
245         fput(file);
246 no_file:
247         security_shm_free(shp);
248         ipc_rcu_putref(shp);
249         return error;
250 }
251
252 asmlinkage long sys_shmget (key_t key, size_t size, int shmflg)
253 {
254         struct shmid_kernel *shp;
255         int err, id = 0;
256
257         down(&shm_ids.sem);
258         if (key == IPC_PRIVATE) {
259                 err = newseg(key, shmflg, size);
260         } else if ((id = ipc_findkey(&shm_ids, key)) == -1) {
261                 if (!(shmflg & IPC_CREAT))
262                         err = -ENOENT;
263                 else
264                         err = newseg(key, shmflg, size);
265         } else if ((shmflg & IPC_CREAT) && (shmflg & IPC_EXCL)) {
266                 err = -EEXIST;
267         } else {
268                 shp = shm_lock(id);
269                 if(shp==NULL)
270                         BUG();
271                 if (shp->shm_segsz < size)
272                         err = -EINVAL;
273                 else if (ipcperms(&shp->shm_perm, shmflg))
274                         err = -EACCES;
275                 else {
276                         int shmid = shm_buildid(id, shp->shm_perm.seq);
277                         err = security_shm_associate(shp, shmflg);
278                         if (!err)
279                                 err = shmid;
280                 }
281                 shm_unlock(shp);
282         }
283         up(&shm_ids.sem);
284
285         return err;
286 }
287
288 static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
289 {
290         switch(version) {
291         case IPC_64:
292                 return copy_to_user(buf, in, sizeof(*in));
293         case IPC_OLD:
294             {
295                 struct shmid_ds out;
296
297                 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
298                 out.shm_segsz   = in->shm_segsz;
299                 out.shm_atime   = in->shm_atime;
300                 out.shm_dtime   = in->shm_dtime;
301                 out.shm_ctime   = in->shm_ctime;
302                 out.shm_cpid    = in->shm_cpid;
303                 out.shm_lpid    = in->shm_lpid;
304                 out.shm_nattch  = in->shm_nattch;
305
306                 return copy_to_user(buf, &out, sizeof(out));
307             }
308         default:
309                 return -EINVAL;
310         }
311 }
312
313 struct shm_setbuf {
314         uid_t   uid;
315         gid_t   gid;
316         mode_t  mode;
317 };      
318
319 static inline unsigned long copy_shmid_from_user(struct shm_setbuf *out, void __user *buf, int version)
320 {
321         switch(version) {
322         case IPC_64:
323             {
324                 struct shmid64_ds tbuf;
325
326                 if (copy_from_user(&tbuf, buf, sizeof(tbuf)))
327                         return -EFAULT;
328
329                 out->uid        = tbuf.shm_perm.uid;
330                 out->gid        = tbuf.shm_perm.gid;
331                 out->mode       = tbuf.shm_flags;
332
333                 return 0;
334             }
335         case IPC_OLD:
336             {
337                 struct shmid_ds tbuf_old;
338
339                 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
340                         return -EFAULT;
341
342                 out->uid        = tbuf_old.shm_perm.uid;
343                 out->gid        = tbuf_old.shm_perm.gid;
344                 out->mode       = tbuf_old.shm_flags;
345
346                 return 0;
347             }
348         default:
349                 return -EINVAL;
350         }
351 }
352
353 static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
354 {
355         switch(version) {
356         case IPC_64:
357                 return copy_to_user(buf, in, sizeof(*in));
358         case IPC_OLD:
359             {
360                 struct shminfo out;
361
362                 if(in->shmmax > INT_MAX)
363                         out.shmmax = INT_MAX;
364                 else
365                         out.shmmax = (int)in->shmmax;
366
367                 out.shmmin      = in->shmmin;
368                 out.shmmni      = in->shmmni;
369                 out.shmseg      = in->shmseg;
370                 out.shmall      = in->shmall; 
371
372                 return copy_to_user(buf, &out, sizeof(out));
373             }
374         default:
375                 return -EINVAL;
376         }
377 }
378
379 static void shm_get_stat(unsigned long *rss, unsigned long *swp) 
380 {
381         int i;
382
383         *rss = 0;
384         *swp = 0;
385
386         for (i = 0; i <= shm_ids.max_id; i++) {
387                 struct shmid_kernel *shp;
388                 struct inode *inode;
389
390                 shp = shm_get(i);
391                 if(!shp)
392                         continue;
393
394                 inode = shp->shm_file->f_dentry->d_inode;
395
396                 if (is_file_hugepages(shp->shm_file)) {
397                         struct address_space *mapping = inode->i_mapping;
398                         *rss += (HPAGE_SIZE/PAGE_SIZE)*mapping->nrpages;
399                 } else {
400                         struct shmem_inode_info *info = SHMEM_I(inode);
401                         spin_lock(&info->lock);
402                         *rss += inode->i_mapping->nrpages;
403                         *swp += info->swapped;
404                         spin_unlock(&info->lock);
405                 }
406         }
407 }
408
409 asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
410 {
411         struct shm_setbuf setbuf;
412         struct shmid_kernel *shp;
413         int err, version;
414
415         if (cmd < 0 || shmid < 0) {
416                 err = -EINVAL;
417                 goto out;
418         }
419
420         version = ipc_parse_version(&cmd);
421
422         switch (cmd) { /* replace with proc interface ? */
423         case IPC_INFO:
424         {
425                 struct shminfo64 shminfo;
426
427                 err = security_shm_shmctl(NULL, cmd);
428                 if (err)
429                         return err;
430
431                 memset(&shminfo,0,sizeof(shminfo));
432                 shminfo.shmmni = shminfo.shmseg = shm_ctlmni;
433                 shminfo.shmmax = shm_ctlmax;
434                 shminfo.shmall = shm_ctlall;
435
436                 shminfo.shmmin = SHMMIN;
437                 if(copy_shminfo_to_user (buf, &shminfo, version))
438                         return -EFAULT;
439                 /* reading a integer is always atomic */
440                 err= shm_ids.max_id;
441                 if(err<0)
442                         err = 0;
443                 goto out;
444         }
445         case SHM_INFO:
446         {
447                 struct shm_info shm_info;
448
449                 err = security_shm_shmctl(NULL, cmd);
450                 if (err)
451                         return err;
452
453                 memset(&shm_info,0,sizeof(shm_info));
454                 down(&shm_ids.sem);
455                 shm_info.used_ids = shm_ids.in_use;
456                 shm_get_stat (&shm_info.shm_rss, &shm_info.shm_swp);
457                 shm_info.shm_tot = shm_tot;
458                 shm_info.swap_attempts = 0;
459                 shm_info.swap_successes = 0;
460                 err = shm_ids.max_id;
461                 up(&shm_ids.sem);
462                 if(copy_to_user (buf, &shm_info, sizeof(shm_info))) {
463                         err = -EFAULT;
464                         goto out;
465                 }
466
467                 err = err < 0 ? 0 : err;
468                 goto out;
469         }
470         case SHM_STAT:
471         case IPC_STAT:
472         {
473                 struct shmid64_ds tbuf;
474                 int result;
475                 memset(&tbuf, 0, sizeof(tbuf));
476                 shp = shm_lock(shmid);
477                 if(shp==NULL) {
478                         err = -EINVAL;
479                         goto out;
480                 } else if(cmd==SHM_STAT) {
481                         err = -EINVAL;
482                         if (shmid > shm_ids.max_id)
483                                 goto out_unlock;
484                         result = shm_buildid(shmid, shp->shm_perm.seq);
485                 } else {
486                         err = shm_checkid(shp,shmid);
487                         if(err)
488                                 goto out_unlock;
489                         result = 0;
490                 }
491                 err=-EACCES;
492                 if (ipcperms (&shp->shm_perm, S_IRUGO))
493                         goto out_unlock;
494                 err = security_shm_shmctl(shp, cmd);
495                 if (err)
496                         goto out_unlock;
497                 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
498                 tbuf.shm_segsz  = shp->shm_segsz;
499                 tbuf.shm_atime  = shp->shm_atim;
500                 tbuf.shm_dtime  = shp->shm_dtim;
501                 tbuf.shm_ctime  = shp->shm_ctim;
502                 tbuf.shm_cpid   = shp->shm_cprid;
503                 tbuf.shm_lpid   = shp->shm_lprid;
504                 if (!is_file_hugepages(shp->shm_file))
505                         tbuf.shm_nattch = shp->shm_nattch;
506                 else
507                         tbuf.shm_nattch = file_count(shp->shm_file) - 1;
508                 shm_unlock(shp);
509                 if(copy_shmid_to_user (buf, &tbuf, version))
510                         err = -EFAULT;
511                 else
512                         err = result;
513                 goto out;
514         }
515         case SHM_LOCK:
516         case SHM_UNLOCK:
517         {
518                 shp = shm_lock(shmid);
519                 if(shp==NULL) {
520                         err = -EINVAL;
521                         goto out;
522                 }
523                 err = shm_checkid(shp,shmid);
524                 if(err)
525                         goto out_unlock;
526
527                 if (!capable(CAP_IPC_LOCK)) {
528                         err = -EPERM;
529                         if (current->euid != shp->shm_perm.uid &&
530                             current->euid != shp->shm_perm.cuid)
531                                 goto out_unlock;
532                         if (cmd == SHM_LOCK &&
533                             !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur)
534                                 goto out_unlock;
535                 }
536
537                 err = security_shm_shmctl(shp, cmd);
538                 if (err)
539                         goto out_unlock;
540                 
541                 if(cmd==SHM_LOCK) {
542                         struct user_struct * user = current->user;
543                         if (!is_file_hugepages(shp->shm_file)) {
544                                 err = shmem_lock(shp->shm_file, 1, user);
545                                 if (!err) {
546                                         shp->shm_flags |= SHM_LOCKED;
547                                         shp->mlock_user = user;
548                                 }
549                         }
550                 } else if (!is_file_hugepages(shp->shm_file)) {
551                         shmem_lock(shp->shm_file, 0, shp->mlock_user);
552                         shp->shm_flags &= ~SHM_LOCKED;
553                         shp->mlock_user = NULL;
554                 }
555                 shm_unlock(shp);
556                 goto out;
557         }
558         case IPC_RMID:
559         {
560                 /*
561                  *      We cannot simply remove the file. The SVID states
562                  *      that the block remains until the last person
563                  *      detaches from it, then is deleted. A shmat() on
564                  *      an RMID segment is legal in older Linux and if 
565                  *      we change it apps break...
566                  *
567                  *      Instead we set a destroyed flag, and then blow
568                  *      the name away when the usage hits zero.
569                  */
570                 down(&shm_ids.sem);
571                 shp = shm_lock(shmid);
572                 err = -EINVAL;
573                 if (shp == NULL) 
574                         goto out_up;
575                 err = shm_checkid(shp, shmid);
576                 if(err)
577                         goto out_unlock_up;
578
579                 if (current->euid != shp->shm_perm.uid &&
580                     current->euid != shp->shm_perm.cuid && 
581                     !capable(CAP_SYS_ADMIN)) {
582                         err=-EPERM;
583                         goto out_unlock_up;
584                 }
585
586                 err = security_shm_shmctl(shp, cmd);
587                 if (err)
588                         goto out_unlock_up;
589
590                 if (shp->shm_nattch){
591                         shp->shm_flags |= SHM_DEST;
592                         /* Do not find it any more */
593                         shp->shm_perm.key = IPC_PRIVATE;
594                         shm_unlock(shp);
595                 } else
596                         shm_destroy (shp);
597                 up(&shm_ids.sem);
598                 goto out;
599         }
600
601         case IPC_SET:
602         {
603                 if (copy_shmid_from_user (&setbuf, buf, version)) {
604                         err = -EFAULT;
605                         goto out;
606                 }
607                 if ((err = audit_ipc_perms(0, setbuf.uid, setbuf.gid, setbuf.mode)))
608                         return err;
609                 down(&shm_ids.sem);
610                 shp = shm_lock(shmid);
611                 err=-EINVAL;
612                 if(shp==NULL)
613                         goto out_up;
614                 err = shm_checkid(shp,shmid);
615                 if(err)
616                         goto out_unlock_up;
617                 err=-EPERM;
618                 if (current->euid != shp->shm_perm.uid &&
619                     current->euid != shp->shm_perm.cuid && 
620                     !capable(CAP_SYS_ADMIN)) {
621                         goto out_unlock_up;
622                 }
623
624                 err = security_shm_shmctl(shp, cmd);
625                 if (err)
626                         goto out_unlock_up;
627                 
628                 shp->shm_perm.uid = setbuf.uid;
629                 shp->shm_perm.gid = setbuf.gid;
630                 shp->shm_flags = (shp->shm_flags & ~S_IRWXUGO)
631                         | (setbuf.mode & S_IRWXUGO);
632                 shp->shm_ctim = get_seconds();
633                 break;
634         }
635
636         default:
637                 err = -EINVAL;
638                 goto out;
639         }
640
641         err = 0;
642 out_unlock_up:
643         shm_unlock(shp);
644 out_up:
645         up(&shm_ids.sem);
646         goto out;
647 out_unlock:
648         shm_unlock(shp);
649 out:
650         return err;
651 }
652
653 /*
654  * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
655  *
656  * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
657  * "raddr" thing points to kernel space, and there has to be a wrapper around
658  * this.
659  */
660 long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
661 {
662         struct shmid_kernel *shp;
663         unsigned long addr;
664         unsigned long size;
665         struct file * file;
666         int    err;
667         unsigned long flags;
668         unsigned long prot;
669         unsigned long o_flags;
670         int acc_mode;
671         void *user_addr;
672
673         if (shmid < 0) {
674                 err = -EINVAL;
675                 goto out;
676         } else if ((addr = (ulong)shmaddr)) {
677                 if (addr & (SHMLBA-1)) {
678                         if (shmflg & SHM_RND)
679                                 addr &= ~(SHMLBA-1);       /* round down */
680                         else
681 #ifndef __ARCH_FORCE_SHMLBA
682                                 if (addr & ~PAGE_MASK)
683 #endif
684                                         return -EINVAL;
685                 }
686                 flags = MAP_SHARED | MAP_FIXED;
687         } else {
688                 if ((shmflg & SHM_REMAP))
689                         return -EINVAL;
690
691                 flags = MAP_SHARED;
692         }
693
694         if (shmflg & SHM_RDONLY) {
695                 prot = PROT_READ;
696                 o_flags = O_RDONLY;
697                 acc_mode = S_IRUGO;
698         } else {
699                 prot = PROT_READ | PROT_WRITE;
700                 o_flags = O_RDWR;
701                 acc_mode = S_IRUGO | S_IWUGO;
702         }
703         if (shmflg & SHM_EXEC) {
704                 prot |= PROT_EXEC;
705                 acc_mode |= S_IXUGO;
706         }
707
708         /*
709          * We cannot rely on the fs check since SYSV IPC does have an
710          * additional creator id...
711          */
712         shp = shm_lock(shmid);
713         if(shp == NULL) {
714                 err = -EINVAL;
715                 goto out;
716         }
717         err = shm_checkid(shp,shmid);
718         if (err) {
719                 shm_unlock(shp);
720                 goto out;
721         }
722         if (ipcperms(&shp->shm_perm, acc_mode)) {
723                 shm_unlock(shp);
724                 err = -EACCES;
725                 goto out;
726         }
727
728         err = security_shm_shmat(shp, shmaddr, shmflg);
729         if (err) {
730                 shm_unlock(shp);
731                 return err;
732         }
733                 
734         file = shp->shm_file;
735         size = i_size_read(file->f_dentry->d_inode);
736         shp->shm_nattch++;
737         shm_unlock(shp);
738
739         down_write(&current->mm->mmap_sem);
740         if (addr && !(shmflg & SHM_REMAP)) {
741                 user_addr = ERR_PTR(-EINVAL);
742                 if (find_vma_intersection(current->mm, addr, addr + size))
743                         goto invalid;
744                 /*
745                  * If shm segment goes below stack, make sure there is some
746                  * space left for the stack to grow (at least 4 pages).
747                  */
748                 if (addr < current->mm->start_stack &&
749                     addr > current->mm->start_stack - size - PAGE_SIZE * 5)
750                         goto invalid;
751         }
752                 
753         user_addr = (void*) do_mmap (file, addr, size, prot, flags, 0);
754
755 invalid:
756         up_write(&current->mm->mmap_sem);
757
758         down (&shm_ids.sem);
759         if(!(shp = shm_lock(shmid)))
760                 BUG();
761         shp->shm_nattch--;
762         if(shp->shm_nattch == 0 &&
763            shp->shm_flags & SHM_DEST)
764                 shm_destroy (shp);
765         else
766                 shm_unlock(shp);
767         up (&shm_ids.sem);
768
769         *raddr = (unsigned long) user_addr;
770         err = 0;
771         if (IS_ERR(user_addr))
772                 err = PTR_ERR(user_addr);
773 out:
774         return err;
775 }
776
777 asmlinkage long sys_shmat(int shmid, char __user *shmaddr, int shmflg)
778 {
779         unsigned long ret;
780         long err;
781
782         err = do_shmat(shmid, shmaddr, shmflg, &ret);
783         if (err)
784                 return err;
785         force_successful_syscall_return();
786         return (long)ret;
787 }
788
789 /*
790  * detach and kill segment if marked destroyed.
791  * The work is done in shm_close.
792  */
793 asmlinkage long sys_shmdt(char __user *shmaddr)
794 {
795         struct mm_struct *mm = current->mm;
796         struct vm_area_struct *vma, *next;
797         unsigned long addr = (unsigned long)shmaddr;
798         loff_t size = 0;
799         int retval = -EINVAL;
800
801         down_write(&mm->mmap_sem);
802
803         /*
804          * This function tries to be smart and unmap shm segments that
805          * were modified by partial mlock or munmap calls:
806          * - It first determines the size of the shm segment that should be
807          *   unmapped: It searches for a vma that is backed by shm and that
808          *   started at address shmaddr. It records it's size and then unmaps
809          *   it.
810          * - Then it unmaps all shm vmas that started at shmaddr and that
811          *   are within the initially determined size.
812          * Errors from do_munmap are ignored: the function only fails if
813          * it's called with invalid parameters or if it's called to unmap
814          * a part of a vma. Both calls in this function are for full vmas,
815          * the parameters are directly copied from the vma itself and always
816          * valid - therefore do_munmap cannot fail. (famous last words?)
817          */
818         /*
819          * If it had been mremap()'d, the starting address would not
820          * match the usual checks anyway. So assume all vma's are
821          * above the starting address given.
822          */
823         vma = find_vma(mm, addr);
824
825         while (vma) {
826                 next = vma->vm_next;
827
828                 /*
829                  * Check if the starting address would match, i.e. it's
830                  * a fragment created by mprotect() and/or munmap(), or it
831                  * otherwise it starts at this address with no hassles.
832                  */
833                 if ((vma->vm_ops == &shm_vm_ops || is_vm_hugetlb_page(vma)) &&
834                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
835
836
837                         size = vma->vm_file->f_dentry->d_inode->i_size;
838                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
839                         /*
840                          * We discovered the size of the shm segment, so
841                          * break out of here and fall through to the next
842                          * loop that uses the size information to stop
843                          * searching for matching vma's.
844                          */
845                         retval = 0;
846                         vma = next;
847                         break;
848                 }
849                 vma = next;
850         }
851
852         /*
853          * We need look no further than the maximum address a fragment
854          * could possibly have landed at. Also cast things to loff_t to
855          * prevent overflows and make comparisions vs. equal-width types.
856          */
857         while (vma && (loff_t)(vma->vm_end - addr) <= size) {
858                 next = vma->vm_next;
859
860                 /* finding a matching vma now does not alter retval */
861                 if ((vma->vm_ops == &shm_vm_ops || is_vm_hugetlb_page(vma)) &&
862                         (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
863
864                         do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
865                 vma = next;
866         }
867
868         up_write(&mm->mmap_sem);
869         return retval;
870 }
871
872 #ifdef CONFIG_PROC_FS
873 static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
874 {
875         struct shmid_kernel *shp = it;
876         char *format;
877
878 #define SMALL_STRING "%10d %10d  %4o %10u %5u %5u  %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
879 #define BIG_STRING   "%10d %10d  %4o %21u %5u %5u  %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
880
881         if (sizeof(size_t) <= sizeof(int))
882                 format = SMALL_STRING;
883         else
884                 format = BIG_STRING;
885         return seq_printf(s, format,
886                           shp->shm_perm.key,
887                           shp->id,
888                           shp->shm_flags,
889                           shp->shm_segsz,
890                           shp->shm_cprid,
891                           shp->shm_lprid,
892                           is_file_hugepages(shp->shm_file) ? (file_count(shp->shm_file) - 1) : shp->shm_nattch,
893                           shp->shm_perm.uid,
894                           shp->shm_perm.gid,
895                           shp->shm_perm.cuid,
896                           shp->shm_perm.cgid,
897                           shp->shm_atim,
898                           shp->shm_dtim,
899                           shp->shm_ctim);
900 }
901 #endif