x86, irq: Kill io_apic_renumber_irq
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / ipc / shm.c
blob1a314c89f93cfbffa46d14e00641708147b1a918
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.
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>
16 * support for audit of ipc object properties and permission changes
17 * Dustin Kirkland <dustin.kirkland@us.ibm.com>
19 * namespaces support
20 * OpenVZ, SWsoft Inc.
21 * Pavel Emelianov <xemul@openvz.org>
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>
43 #include <asm/uaccess.h>
45 #include "util.h"
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;
54 #define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data))
56 static const struct file_operations shm_file_operations;
57 static const struct vm_operations_struct shm_vm_ops;
59 #define shm_ids(ns) ((ns)->ids[IPC_SHM_IDS])
61 #define shm_unlock(shp) \
62 ipc_unlock(&(shp)->shm_perm)
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
72 void shm_init_ns(struct ipc_namespace *ns)
74 ns->shm_ctlmax = SHMMAX;
75 ns->shm_ctlall = SHMALL;
76 ns->shm_ctlmni = SHMMNI;
77 ns->shm_tot = 0;
78 ipc_init_ids(&shm_ids(ns));
82 * Called with shm_ids.rw_mutex (writer) and the shp structure locked.
83 * Only shm_ids.rw_mutex remains locked on exit.
85 static void do_shm_rmid(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
87 struct shmid_kernel *shp;
88 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
90 if (shp->shm_nattch){
91 shp->shm_perm.mode |= SHM_DEST;
92 /* Do not find it any more */
93 shp->shm_perm.key = IPC_PRIVATE;
94 shm_unlock(shp);
95 } else
96 shm_destroy(ns, shp);
99 #ifdef CONFIG_IPC_NS
100 void shm_exit_ns(struct ipc_namespace *ns)
102 free_ipcs(ns, &shm_ids(ns), do_shm_rmid);
103 idr_destroy(&ns->ids[IPC_SHM_IDS].ipcs_idr);
105 #endif
107 void __init shm_init (void)
109 shm_init_ns(&init_ipc_ns);
110 ipc_init_proc_interface("sysvipc/shm",
111 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime\n",
112 IPC_SHM_IDS, sysvipc_shm_proc_show);
116 * shm_lock_(check_) routines are called in the paths where the rw_mutex
117 * is not necessarily held.
119 static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
121 struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id);
123 if (IS_ERR(ipcp))
124 return (struct shmid_kernel *)ipcp;
126 return container_of(ipcp, struct shmid_kernel, shm_perm);
129 static inline struct shmid_kernel *shm_lock_check(struct ipc_namespace *ns,
130 int id)
132 struct kern_ipc_perm *ipcp = ipc_lock_check(&shm_ids(ns), id);
134 if (IS_ERR(ipcp))
135 return (struct shmid_kernel *)ipcp;
137 return container_of(ipcp, struct shmid_kernel, shm_perm);
140 static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
142 ipc_rmid(&shm_ids(ns), &s->shm_perm);
146 /* This is called by fork, once for every shm attach. */
147 static void shm_open(struct vm_area_struct *vma)
149 struct file *file = vma->vm_file;
150 struct shm_file_data *sfd = shm_file_data(file);
151 struct shmid_kernel *shp;
153 shp = shm_lock(sfd->ns, sfd->id);
154 BUG_ON(IS_ERR(shp));
155 shp->shm_atim = get_seconds();
156 shp->shm_lprid = task_tgid_vnr(current);
157 shp->shm_nattch++;
158 shm_unlock(shp);
162 * shm_destroy - free the struct shmid_kernel
164 * @ns: namespace
165 * @shp: struct to free
167 * It has to be called with shp and shm_ids.rw_mutex (writer) locked,
168 * but returns with shp unlocked and freed.
170 static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
172 ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
173 shm_rmid(ns, shp);
174 shm_unlock(shp);
175 if (!is_file_hugepages(shp->shm_file))
176 shmem_lock(shp->shm_file, 0, shp->mlock_user);
177 else if (shp->mlock_user)
178 user_shm_unlock(shp->shm_file->f_path.dentry->d_inode->i_size,
179 shp->mlock_user);
180 fput (shp->shm_file);
181 security_shm_free(shp);
182 ipc_rcu_putref(shp);
186 * remove the attach descriptor vma.
187 * free memory for segment if it is marked destroyed.
188 * The descriptor has already been removed from the current->mm->mmap list
189 * and will later be kfree()d.
191 static void shm_close(struct vm_area_struct *vma)
193 struct file * file = vma->vm_file;
194 struct shm_file_data *sfd = shm_file_data(file);
195 struct shmid_kernel *shp;
196 struct ipc_namespace *ns = sfd->ns;
198 down_write(&shm_ids(ns).rw_mutex);
199 /* remove from the list of attaches of the shm segment */
200 shp = shm_lock(ns, sfd->id);
201 BUG_ON(IS_ERR(shp));
202 shp->shm_lprid = task_tgid_vnr(current);
203 shp->shm_dtim = get_seconds();
204 shp->shm_nattch--;
205 if(shp->shm_nattch == 0 &&
206 shp->shm_perm.mode & SHM_DEST)
207 shm_destroy(ns, shp);
208 else
209 shm_unlock(shp);
210 up_write(&shm_ids(ns).rw_mutex);
213 static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
215 struct file *file = vma->vm_file;
216 struct shm_file_data *sfd = shm_file_data(file);
218 return sfd->vm_ops->fault(vma, vmf);
221 #ifdef CONFIG_NUMA
222 static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
224 struct file *file = vma->vm_file;
225 struct shm_file_data *sfd = shm_file_data(file);
226 int err = 0;
227 if (sfd->vm_ops->set_policy)
228 err = sfd->vm_ops->set_policy(vma, new);
229 return err;
232 static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
233 unsigned long addr)
235 struct file *file = vma->vm_file;
236 struct shm_file_data *sfd = shm_file_data(file);
237 struct mempolicy *pol = NULL;
239 if (sfd->vm_ops->get_policy)
240 pol = sfd->vm_ops->get_policy(vma, addr);
241 else if (vma->vm_policy)
242 pol = vma->vm_policy;
244 return pol;
246 #endif
248 static int shm_mmap(struct file * file, struct vm_area_struct * vma)
250 struct shm_file_data *sfd = shm_file_data(file);
251 int ret;
253 ret = sfd->file->f_op->mmap(sfd->file, vma);
254 if (ret != 0)
255 return ret;
256 sfd->vm_ops = vma->vm_ops;
257 #ifdef CONFIG_MMU
258 BUG_ON(!sfd->vm_ops->fault);
259 #endif
260 vma->vm_ops = &shm_vm_ops;
261 shm_open(vma);
263 return ret;
266 static int shm_release(struct inode *ino, struct file *file)
268 struct shm_file_data *sfd = shm_file_data(file);
270 put_ipc_ns(sfd->ns);
271 shm_file_data(file) = NULL;
272 kfree(sfd);
273 return 0;
276 static int shm_fsync(struct file *file, struct dentry *dentry, int datasync)
278 int (*fsync) (struct file *, struct dentry *, int datasync);
279 struct shm_file_data *sfd = shm_file_data(file);
280 int ret = -EINVAL;
282 fsync = sfd->file->f_op->fsync;
283 if (fsync)
284 ret = fsync(sfd->file, sfd->file->f_path.dentry, datasync);
285 return ret;
288 static unsigned long shm_get_unmapped_area(struct file *file,
289 unsigned long addr, unsigned long len, unsigned long pgoff,
290 unsigned long flags)
292 struct shm_file_data *sfd = shm_file_data(file);
293 return sfd->file->f_op->get_unmapped_area(sfd->file, addr, len,
294 pgoff, flags);
297 static const struct file_operations shm_file_operations = {
298 .mmap = shm_mmap,
299 .fsync = shm_fsync,
300 .release = shm_release,
301 #ifndef CONFIG_MMU
302 .get_unmapped_area = shm_get_unmapped_area,
303 #endif
306 static const struct file_operations shm_file_operations_huge = {
307 .mmap = shm_mmap,
308 .fsync = shm_fsync,
309 .release = shm_release,
310 .get_unmapped_area = shm_get_unmapped_area,
313 int is_file_shm_hugepages(struct file *file)
315 return file->f_op == &shm_file_operations_huge;
318 static const struct vm_operations_struct shm_vm_ops = {
319 .open = shm_open, /* callback for a new vm-area open */
320 .close = shm_close, /* callback for when the vm-area is released */
321 .fault = shm_fault,
322 #if defined(CONFIG_NUMA)
323 .set_policy = shm_set_policy,
324 .get_policy = shm_get_policy,
325 #endif
329 * newseg - Create a new shared memory segment
330 * @ns: namespace
331 * @params: ptr to the structure that contains key, size and shmflg
333 * Called with shm_ids.rw_mutex held as a writer.
336 static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
338 key_t key = params->key;
339 int shmflg = params->flg;
340 size_t size = params->u.size;
341 int error;
342 struct shmid_kernel *shp;
343 int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
344 struct file * file;
345 char name[13];
346 int id;
347 int acctflag = 0;
349 if (size < SHMMIN || size > ns->shm_ctlmax)
350 return -EINVAL;
352 if (ns->shm_tot + numpages > ns->shm_ctlall)
353 return -ENOSPC;
355 shp = ipc_rcu_alloc(sizeof(*shp));
356 if (!shp)
357 return -ENOMEM;
359 shp->shm_perm.key = key;
360 shp->shm_perm.mode = (shmflg & S_IRWXUGO);
361 shp->mlock_user = NULL;
363 shp->shm_perm.security = NULL;
364 error = security_shm_alloc(shp);
365 if (error) {
366 ipc_rcu_putref(shp);
367 return error;
370 sprintf (name, "SYSV%08x", key);
371 if (shmflg & SHM_HUGETLB) {
372 /* hugetlb_file_setup applies strict accounting */
373 if (shmflg & SHM_NORESERVE)
374 acctflag = VM_NORESERVE;
375 file = hugetlb_file_setup(name, size, acctflag,
376 &shp->mlock_user, HUGETLB_SHMFS_INODE);
377 } else {
379 * Do not allow no accounting for OVERCOMMIT_NEVER, even
380 * if it's asked for.
382 if ((shmflg & SHM_NORESERVE) &&
383 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
384 acctflag = VM_NORESERVE;
385 file = shmem_file_setup(name, size, acctflag);
387 error = PTR_ERR(file);
388 if (IS_ERR(file))
389 goto no_file;
391 id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
392 if (id < 0) {
393 error = id;
394 goto no_id;
397 shp->shm_cprid = task_tgid_vnr(current);
398 shp->shm_lprid = 0;
399 shp->shm_atim = shp->shm_dtim = 0;
400 shp->shm_ctim = get_seconds();
401 shp->shm_segsz = size;
402 shp->shm_nattch = 0;
403 shp->shm_file = file;
405 * shmid gets reported as "inode#" in /proc/pid/maps.
406 * proc-ps tools use this. Changing this will break them.
408 file->f_dentry->d_inode->i_ino = shp->shm_perm.id;
410 ns->shm_tot += numpages;
411 error = shp->shm_perm.id;
412 shm_unlock(shp);
413 return error;
415 no_id:
416 if (is_file_hugepages(file) && shp->mlock_user)
417 user_shm_unlock(size, shp->mlock_user);
418 fput(file);
419 no_file:
420 security_shm_free(shp);
421 ipc_rcu_putref(shp);
422 return error;
426 * Called with shm_ids.rw_mutex and ipcp locked.
428 static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)
430 struct shmid_kernel *shp;
432 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
433 return security_shm_associate(shp, shmflg);
437 * Called with shm_ids.rw_mutex and ipcp locked.
439 static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
440 struct ipc_params *params)
442 struct shmid_kernel *shp;
444 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
445 if (shp->shm_segsz < params->u.size)
446 return -EINVAL;
448 return 0;
451 SYSCALL_DEFINE3(shmget, key_t, key, size_t, size, int, shmflg)
453 struct ipc_namespace *ns;
454 struct ipc_ops shm_ops;
455 struct ipc_params shm_params;
457 ns = current->nsproxy->ipc_ns;
459 shm_ops.getnew = newseg;
460 shm_ops.associate = shm_security;
461 shm_ops.more_checks = shm_more_checks;
463 shm_params.key = key;
464 shm_params.flg = shmflg;
465 shm_params.u.size = size;
467 return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
470 static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
472 switch(version) {
473 case IPC_64:
474 return copy_to_user(buf, in, sizeof(*in));
475 case IPC_OLD:
477 struct shmid_ds out;
479 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
480 out.shm_segsz = in->shm_segsz;
481 out.shm_atime = in->shm_atime;
482 out.shm_dtime = in->shm_dtime;
483 out.shm_ctime = in->shm_ctime;
484 out.shm_cpid = in->shm_cpid;
485 out.shm_lpid = in->shm_lpid;
486 out.shm_nattch = in->shm_nattch;
488 return copy_to_user(buf, &out, sizeof(out));
490 default:
491 return -EINVAL;
495 static inline unsigned long
496 copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version)
498 switch(version) {
499 case IPC_64:
500 if (copy_from_user(out, buf, sizeof(*out)))
501 return -EFAULT;
502 return 0;
503 case IPC_OLD:
505 struct shmid_ds tbuf_old;
507 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
508 return -EFAULT;
510 out->shm_perm.uid = tbuf_old.shm_perm.uid;
511 out->shm_perm.gid = tbuf_old.shm_perm.gid;
512 out->shm_perm.mode = tbuf_old.shm_perm.mode;
514 return 0;
516 default:
517 return -EINVAL;
521 static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
523 switch(version) {
524 case IPC_64:
525 return copy_to_user(buf, in, sizeof(*in));
526 case IPC_OLD:
528 struct shminfo out;
530 if(in->shmmax > INT_MAX)
531 out.shmmax = INT_MAX;
532 else
533 out.shmmax = (int)in->shmmax;
535 out.shmmin = in->shmmin;
536 out.shmmni = in->shmmni;
537 out.shmseg = in->shmseg;
538 out.shmall = in->shmall;
540 return copy_to_user(buf, &out, sizeof(out));
542 default:
543 return -EINVAL;
548 * Called with shm_ids.rw_mutex held as a reader
550 static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
551 unsigned long *swp)
553 int next_id;
554 int total, in_use;
556 *rss = 0;
557 *swp = 0;
559 in_use = shm_ids(ns).in_use;
561 for (total = 0, next_id = 0; total < in_use; next_id++) {
562 struct kern_ipc_perm *ipc;
563 struct shmid_kernel *shp;
564 struct inode *inode;
566 ipc = idr_find(&shm_ids(ns).ipcs_idr, next_id);
567 if (ipc == NULL)
568 continue;
569 shp = container_of(ipc, struct shmid_kernel, shm_perm);
571 inode = shp->shm_file->f_path.dentry->d_inode;
573 if (is_file_hugepages(shp->shm_file)) {
574 struct address_space *mapping = inode->i_mapping;
575 struct hstate *h = hstate_file(shp->shm_file);
576 *rss += pages_per_huge_page(h) * mapping->nrpages;
577 } else {
578 #ifdef CONFIG_SHMEM
579 struct shmem_inode_info *info = SHMEM_I(inode);
580 spin_lock(&info->lock);
581 *rss += inode->i_mapping->nrpages;
582 *swp += info->swapped;
583 spin_unlock(&info->lock);
584 #else
585 *rss += inode->i_mapping->nrpages;
586 #endif
589 total++;
594 * This function handles some shmctl commands which require the rw_mutex
595 * to be held in write mode.
596 * NOTE: no locks must be held, the rw_mutex is taken inside this function.
598 static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
599 struct shmid_ds __user *buf, int version)
601 struct kern_ipc_perm *ipcp;
602 struct shmid64_ds shmid64;
603 struct shmid_kernel *shp;
604 int err;
606 if (cmd == IPC_SET) {
607 if (copy_shmid_from_user(&shmid64, buf, version))
608 return -EFAULT;
611 ipcp = ipcctl_pre_down(&shm_ids(ns), shmid, cmd, &shmid64.shm_perm, 0);
612 if (IS_ERR(ipcp))
613 return PTR_ERR(ipcp);
615 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
617 err = security_shm_shmctl(shp, cmd);
618 if (err)
619 goto out_unlock;
620 switch (cmd) {
621 case IPC_RMID:
622 do_shm_rmid(ns, ipcp);
623 goto out_up;
624 case IPC_SET:
625 ipc_update_perm(&shmid64.shm_perm, ipcp);
626 shp->shm_ctim = get_seconds();
627 break;
628 default:
629 err = -EINVAL;
631 out_unlock:
632 shm_unlock(shp);
633 out_up:
634 up_write(&shm_ids(ns).rw_mutex);
635 return err;
638 SYSCALL_DEFINE3(shmctl, int, shmid, int, cmd, struct shmid_ds __user *, buf)
640 struct shmid_kernel *shp;
641 int err, version;
642 struct ipc_namespace *ns;
644 if (cmd < 0 || shmid < 0) {
645 err = -EINVAL;
646 goto out;
649 version = ipc_parse_version(&cmd);
650 ns = current->nsproxy->ipc_ns;
652 switch (cmd) { /* replace with proc interface ? */
653 case IPC_INFO:
655 struct shminfo64 shminfo;
657 err = security_shm_shmctl(NULL, cmd);
658 if (err)
659 return err;
661 memset(&shminfo, 0, sizeof(shminfo));
662 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
663 shminfo.shmmax = ns->shm_ctlmax;
664 shminfo.shmall = ns->shm_ctlall;
666 shminfo.shmmin = SHMMIN;
667 if(copy_shminfo_to_user (buf, &shminfo, version))
668 return -EFAULT;
670 down_read(&shm_ids(ns).rw_mutex);
671 err = ipc_get_maxid(&shm_ids(ns));
672 up_read(&shm_ids(ns).rw_mutex);
674 if(err<0)
675 err = 0;
676 goto out;
678 case SHM_INFO:
680 struct shm_info shm_info;
682 err = security_shm_shmctl(NULL, cmd);
683 if (err)
684 return err;
686 memset(&shm_info, 0, sizeof(shm_info));
687 down_read(&shm_ids(ns).rw_mutex);
688 shm_info.used_ids = shm_ids(ns).in_use;
689 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
690 shm_info.shm_tot = ns->shm_tot;
691 shm_info.swap_attempts = 0;
692 shm_info.swap_successes = 0;
693 err = ipc_get_maxid(&shm_ids(ns));
694 up_read(&shm_ids(ns).rw_mutex);
695 if (copy_to_user(buf, &shm_info, sizeof(shm_info))) {
696 err = -EFAULT;
697 goto out;
700 err = err < 0 ? 0 : err;
701 goto out;
703 case SHM_STAT:
704 case IPC_STAT:
706 struct shmid64_ds tbuf;
707 int result;
709 if (cmd == SHM_STAT) {
710 shp = shm_lock(ns, shmid);
711 if (IS_ERR(shp)) {
712 err = PTR_ERR(shp);
713 goto out;
715 result = shp->shm_perm.id;
716 } else {
717 shp = shm_lock_check(ns, shmid);
718 if (IS_ERR(shp)) {
719 err = PTR_ERR(shp);
720 goto out;
722 result = 0;
724 err = -EACCES;
725 if (ipcperms (&shp->shm_perm, S_IRUGO))
726 goto out_unlock;
727 err = security_shm_shmctl(shp, cmd);
728 if (err)
729 goto out_unlock;
730 memset(&tbuf, 0, sizeof(tbuf));
731 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
732 tbuf.shm_segsz = shp->shm_segsz;
733 tbuf.shm_atime = shp->shm_atim;
734 tbuf.shm_dtime = shp->shm_dtim;
735 tbuf.shm_ctime = shp->shm_ctim;
736 tbuf.shm_cpid = shp->shm_cprid;
737 tbuf.shm_lpid = shp->shm_lprid;
738 tbuf.shm_nattch = shp->shm_nattch;
739 shm_unlock(shp);
740 if(copy_shmid_to_user (buf, &tbuf, version))
741 err = -EFAULT;
742 else
743 err = result;
744 goto out;
746 case SHM_LOCK:
747 case SHM_UNLOCK:
749 struct file *uninitialized_var(shm_file);
751 lru_add_drain_all(); /* drain pagevecs to lru lists */
753 shp = shm_lock_check(ns, shmid);
754 if (IS_ERR(shp)) {
755 err = PTR_ERR(shp);
756 goto out;
759 audit_ipc_obj(&(shp->shm_perm));
761 if (!capable(CAP_IPC_LOCK)) {
762 uid_t euid = current_euid();
763 err = -EPERM;
764 if (euid != shp->shm_perm.uid &&
765 euid != shp->shm_perm.cuid)
766 goto out_unlock;
767 if (cmd == SHM_LOCK && !rlimit(RLIMIT_MEMLOCK))
768 goto out_unlock;
771 err = security_shm_shmctl(shp, cmd);
772 if (err)
773 goto out_unlock;
775 if(cmd==SHM_LOCK) {
776 struct user_struct *user = current_user();
777 if (!is_file_hugepages(shp->shm_file)) {
778 err = shmem_lock(shp->shm_file, 1, user);
779 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)){
780 shp->shm_perm.mode |= SHM_LOCKED;
781 shp->mlock_user = user;
784 } else if (!is_file_hugepages(shp->shm_file)) {
785 shmem_lock(shp->shm_file, 0, shp->mlock_user);
786 shp->shm_perm.mode &= ~SHM_LOCKED;
787 shp->mlock_user = NULL;
789 shm_unlock(shp);
790 goto out;
792 case IPC_RMID:
793 case IPC_SET:
794 err = shmctl_down(ns, shmid, cmd, buf, version);
795 return err;
796 default:
797 return -EINVAL;
800 out_unlock:
801 shm_unlock(shp);
802 out:
803 return err;
807 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
809 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
810 * "raddr" thing points to kernel space, and there has to be a wrapper around
811 * this.
813 long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
815 struct shmid_kernel *shp;
816 unsigned long addr;
817 unsigned long size;
818 struct file * file;
819 int err;
820 unsigned long flags;
821 unsigned long prot;
822 int acc_mode;
823 unsigned long user_addr;
824 struct ipc_namespace *ns;
825 struct shm_file_data *sfd;
826 struct path path;
827 fmode_t f_mode;
829 err = -EINVAL;
830 if (shmid < 0)
831 goto out;
832 else if ((addr = (ulong)shmaddr)) {
833 if (addr & (SHMLBA-1)) {
834 if (shmflg & SHM_RND)
835 addr &= ~(SHMLBA-1); /* round down */
836 else
837 #ifndef __ARCH_FORCE_SHMLBA
838 if (addr & ~PAGE_MASK)
839 #endif
840 goto out;
842 flags = MAP_SHARED | MAP_FIXED;
843 } else {
844 if ((shmflg & SHM_REMAP))
845 goto out;
847 flags = MAP_SHARED;
850 if (shmflg & SHM_RDONLY) {
851 prot = PROT_READ;
852 acc_mode = S_IRUGO;
853 f_mode = FMODE_READ;
854 } else {
855 prot = PROT_READ | PROT_WRITE;
856 acc_mode = S_IRUGO | S_IWUGO;
857 f_mode = FMODE_READ | FMODE_WRITE;
859 if (shmflg & SHM_EXEC) {
860 prot |= PROT_EXEC;
861 acc_mode |= S_IXUGO;
865 * We cannot rely on the fs check since SYSV IPC does have an
866 * additional creator id...
868 ns = current->nsproxy->ipc_ns;
869 shp = shm_lock_check(ns, shmid);
870 if (IS_ERR(shp)) {
871 err = PTR_ERR(shp);
872 goto out;
875 err = -EACCES;
876 if (ipcperms(&shp->shm_perm, acc_mode))
877 goto out_unlock;
879 err = security_shm_shmat(shp, shmaddr, shmflg);
880 if (err)
881 goto out_unlock;
883 path = shp->shm_file->f_path;
884 path_get(&path);
885 shp->shm_nattch++;
886 size = i_size_read(path.dentry->d_inode);
887 shm_unlock(shp);
889 err = -ENOMEM;
890 sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
891 if (!sfd)
892 goto out_put_dentry;
894 file = alloc_file(&path, f_mode,
895 is_file_hugepages(shp->shm_file) ?
896 &shm_file_operations_huge :
897 &shm_file_operations);
898 if (!file)
899 goto out_free;
901 file->private_data = sfd;
902 file->f_mapping = shp->shm_file->f_mapping;
903 sfd->id = shp->shm_perm.id;
904 sfd->ns = get_ipc_ns(ns);
905 sfd->file = shp->shm_file;
906 sfd->vm_ops = NULL;
908 down_write(&current->mm->mmap_sem);
909 if (addr && !(shmflg & SHM_REMAP)) {
910 err = -EINVAL;
911 if (find_vma_intersection(current->mm, addr, addr + size))
912 goto invalid;
914 * If shm segment goes below stack, make sure there is some
915 * space left for the stack to grow (at least 4 pages).
917 if (addr < current->mm->start_stack &&
918 addr > current->mm->start_stack - size - PAGE_SIZE * 5)
919 goto invalid;
922 user_addr = do_mmap (file, addr, size, prot, flags, 0);
923 *raddr = user_addr;
924 err = 0;
925 if (IS_ERR_VALUE(user_addr))
926 err = (long)user_addr;
927 invalid:
928 up_write(&current->mm->mmap_sem);
930 fput(file);
932 out_nattch:
933 down_write(&shm_ids(ns).rw_mutex);
934 shp = shm_lock(ns, shmid);
935 BUG_ON(IS_ERR(shp));
936 shp->shm_nattch--;
937 if(shp->shm_nattch == 0 &&
938 shp->shm_perm.mode & SHM_DEST)
939 shm_destroy(ns, shp);
940 else
941 shm_unlock(shp);
942 up_write(&shm_ids(ns).rw_mutex);
944 out:
945 return err;
947 out_unlock:
948 shm_unlock(shp);
949 goto out;
951 out_free:
952 kfree(sfd);
953 out_put_dentry:
954 path_put(&path);
955 goto out_nattch;
958 SYSCALL_DEFINE3(shmat, int, shmid, char __user *, shmaddr, int, shmflg)
960 unsigned long ret;
961 long err;
963 err = do_shmat(shmid, shmaddr, shmflg, &ret);
964 if (err)
965 return err;
966 force_successful_syscall_return();
967 return (long)ret;
971 * detach and kill segment if marked destroyed.
972 * The work is done in shm_close.
974 SYSCALL_DEFINE1(shmdt, char __user *, shmaddr)
976 struct mm_struct *mm = current->mm;
977 struct vm_area_struct *vma;
978 unsigned long addr = (unsigned long)shmaddr;
979 int retval = -EINVAL;
980 #ifdef CONFIG_MMU
981 loff_t size = 0;
982 struct vm_area_struct *next;
983 #endif
985 if (addr & ~PAGE_MASK)
986 return retval;
988 down_write(&mm->mmap_sem);
991 * This function tries to be smart and unmap shm segments that
992 * were modified by partial mlock or munmap calls:
993 * - It first determines the size of the shm segment that should be
994 * unmapped: It searches for a vma that is backed by shm and that
995 * started at address shmaddr. It records it's size and then unmaps
996 * it.
997 * - Then it unmaps all shm vmas that started at shmaddr and that
998 * are within the initially determined size.
999 * Errors from do_munmap are ignored: the function only fails if
1000 * it's called with invalid parameters or if it's called to unmap
1001 * a part of a vma. Both calls in this function are for full vmas,
1002 * the parameters are directly copied from the vma itself and always
1003 * valid - therefore do_munmap cannot fail. (famous last words?)
1006 * If it had been mremap()'d, the starting address would not
1007 * match the usual checks anyway. So assume all vma's are
1008 * above the starting address given.
1010 vma = find_vma(mm, addr);
1012 #ifdef CONFIG_MMU
1013 while (vma) {
1014 next = vma->vm_next;
1017 * Check if the starting address would match, i.e. it's
1018 * a fragment created by mprotect() and/or munmap(), or it
1019 * otherwise it starts at this address with no hassles.
1021 if ((vma->vm_ops == &shm_vm_ops) &&
1022 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1025 size = vma->vm_file->f_path.dentry->d_inode->i_size;
1026 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1028 * We discovered the size of the shm segment, so
1029 * break out of here and fall through to the next
1030 * loop that uses the size information to stop
1031 * searching for matching vma's.
1033 retval = 0;
1034 vma = next;
1035 break;
1037 vma = next;
1041 * We need look no further than the maximum address a fragment
1042 * could possibly have landed at. Also cast things to loff_t to
1043 * prevent overflows and make comparisions vs. equal-width types.
1045 size = PAGE_ALIGN(size);
1046 while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1047 next = vma->vm_next;
1049 /* finding a matching vma now does not alter retval */
1050 if ((vma->vm_ops == &shm_vm_ops) &&
1051 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1053 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1054 vma = next;
1057 #else /* CONFIG_MMU */
1058 /* under NOMMU conditions, the exact address to be destroyed must be
1059 * given */
1060 retval = -EINVAL;
1061 if (vma->vm_start == addr && vma->vm_ops == &shm_vm_ops) {
1062 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1063 retval = 0;
1066 #endif
1068 up_write(&mm->mmap_sem);
1069 return retval;
1072 #ifdef CONFIG_PROC_FS
1073 static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1075 struct shmid_kernel *shp = it;
1077 #if BITS_PER_LONG <= 32
1078 #define SIZE_SPEC "%10lu"
1079 #else
1080 #define SIZE_SPEC "%21lu"
1081 #endif
1083 return seq_printf(s,
1084 "%10d %10d %4o " SIZE_SPEC " %5u %5u "
1085 "%5lu %5u %5u %5u %5u %10lu %10lu %10lu\n",
1086 shp->shm_perm.key,
1087 shp->shm_perm.id,
1088 shp->shm_perm.mode,
1089 shp->shm_segsz,
1090 shp->shm_cprid,
1091 shp->shm_lprid,
1092 shp->shm_nattch,
1093 shp->shm_perm.uid,
1094 shp->shm_perm.gid,
1095 shp->shm_perm.cuid,
1096 shp->shm_perm.cgid,
1097 shp->shm_atim,
1098 shp->shm_dtim,
1099 shp->shm_ctim);
1101 #endif