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>
21 * Pavel Emelianov <xemul@openvz.org>
24 #include <linux/slab.h>
26 #include <linux/hugetlb.h>
27 #include <linux/shm.h>
28 #include <linux/init.h>
29 #include <linux/file.h>
30 #include <linux/mman.h>
31 #include <linux/shmem_fs.h>
32 #include <linux/security.h>
33 #include <linux/syscalls.h>
34 #include <linux/audit.h>
35 #include <linux/capability.h>
36 #include <linux/ptrace.h>
37 #include <linux/seq_file.h>
38 #include <linux/mutex.h>
39 #include <linux/nsproxy.h>
40 #include <linux/mount.h>
42 #include <asm/uaccess.h>
46 struct shm_file_data {
48 struct ipc_namespace *ns;
50 const struct vm_operations_struct *vm_ops;
53 #define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data))
55 static const struct file_operations shm_file_operations;
56 static struct vm_operations_struct shm_vm_ops;
58 static struct ipc_ids init_shm_ids;
60 #define shm_ids(ns) (*((ns)->ids[IPC_SHM_IDS]))
62 #define shm_lock(ns, id) \
63 ((struct shmid_kernel*)ipc_lock(&shm_ids(ns),id))
64 #define shm_unlock(shp) \
65 ipc_unlock(&(shp)->shm_perm)
66 #define shm_get(ns, id) \
67 ((struct shmid_kernel*)ipc_get(&shm_ids(ns),id))
68 #define shm_buildid(ns, id, seq) \
69 ipc_buildid(&shm_ids(ns), id, seq)
71 static int newseg(struct ipc_namespace *, struct ipc_params *);
72 static void shm_open(struct vm_area_struct *vma);
73 static void shm_close(struct vm_area_struct *vma);
74 static void shm_destroy (struct ipc_namespace *ns, struct shmid_kernel *shp);
76 static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
79 static void __shm_init_ns(struct ipc_namespace *ns, struct ipc_ids *ids)
81 ns->ids[IPC_SHM_IDS] = ids;
82 ns->shm_ctlmax = SHMMAX;
83 ns->shm_ctlall = SHMALL;
84 ns->shm_ctlmni = SHMMNI;
89 static void do_shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *shp)
92 shp->shm_perm.mode |= SHM_DEST;
93 /* Do not find it any more */
94 shp->shm_perm.key = IPC_PRIVATE;
100 int shm_init_ns(struct ipc_namespace *ns)
104 ids = kmalloc(sizeof(struct ipc_ids), GFP_KERNEL);
108 __shm_init_ns(ns, ids);
112 void shm_exit_ns(struct ipc_namespace *ns)
114 struct shmid_kernel *shp;
118 mutex_lock(&shm_ids(ns).mutex);
120 in_use = shm_ids(ns).in_use;
122 for (total = 0, next_id = 0; total < in_use; next_id++) {
123 shp = idr_find(&shm_ids(ns).ipcs_idr, next_id);
126 ipc_lock_by_ptr(&shp->shm_perm);
127 do_shm_rmid(ns, shp);
130 mutex_unlock(&shm_ids(ns).mutex);
132 kfree(ns->ids[IPC_SHM_IDS]);
133 ns->ids[IPC_SHM_IDS] = NULL;
136 void __init shm_init (void)
138 __shm_init_ns(&init_ipc_ns, &init_shm_ids);
139 ipc_init_proc_interface("sysvipc/shm",
140 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime\n",
141 IPC_SHM_IDS, sysvipc_shm_proc_show);
144 static inline int shm_checkid(struct ipc_namespace *ns,
145 struct shmid_kernel *s, int id)
147 if (ipc_checkid(&shm_ids(ns), &s->shm_perm, id))
152 static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
154 ipc_rmid(&shm_ids(ns), &s->shm_perm);
157 static inline int shm_addid(struct ipc_namespace *ns, struct shmid_kernel *shp)
159 return ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
164 /* This is called by fork, once for every shm attach. */
165 static void shm_open(struct vm_area_struct *vma)
167 struct file *file = vma->vm_file;
168 struct shm_file_data *sfd = shm_file_data(file);
169 struct shmid_kernel *shp;
171 shp = shm_lock(sfd->ns, sfd->id);
173 shp->shm_atim = get_seconds();
174 shp->shm_lprid = task_tgid_vnr(current);
180 * shm_destroy - free the struct shmid_kernel
182 * @shp: struct to free
184 * It has to be called with shp and shm_ids.mutex locked,
185 * but returns with shp unlocked and freed.
187 static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
189 ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
192 if (!is_file_hugepages(shp->shm_file))
193 shmem_lock(shp->shm_file, 0, shp->mlock_user);
195 user_shm_unlock(shp->shm_file->f_path.dentry->d_inode->i_size,
197 fput (shp->shm_file);
198 security_shm_free(shp);
203 * remove the attach descriptor vma.
204 * free memory for segment if it is marked destroyed.
205 * The descriptor has already been removed from the current->mm->mmap list
206 * and will later be kfree()d.
208 static void shm_close(struct vm_area_struct *vma)
210 struct file * file = vma->vm_file;
211 struct shm_file_data *sfd = shm_file_data(file);
212 struct shmid_kernel *shp;
213 struct ipc_namespace *ns = sfd->ns;
215 mutex_lock(&shm_ids(ns).mutex);
216 /* remove from the list of attaches of the shm segment */
217 shp = shm_lock(ns, sfd->id);
219 shp->shm_lprid = task_tgid_vnr(current);
220 shp->shm_dtim = get_seconds();
222 if(shp->shm_nattch == 0 &&
223 shp->shm_perm.mode & SHM_DEST)
224 shm_destroy(ns, shp);
227 mutex_unlock(&shm_ids(ns).mutex);
230 static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
232 struct file *file = vma->vm_file;
233 struct shm_file_data *sfd = shm_file_data(file);
235 return sfd->vm_ops->fault(vma, vmf);
239 static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
241 struct file *file = vma->vm_file;
242 struct shm_file_data *sfd = shm_file_data(file);
244 if (sfd->vm_ops->set_policy)
245 err = sfd->vm_ops->set_policy(vma, new);
249 static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
252 struct file *file = vma->vm_file;
253 struct shm_file_data *sfd = shm_file_data(file);
254 struct mempolicy *pol = NULL;
256 if (sfd->vm_ops->get_policy)
257 pol = sfd->vm_ops->get_policy(vma, addr);
258 else if (vma->vm_policy)
259 pol = vma->vm_policy;
261 pol = current->mempolicy;
266 static int shm_mmap(struct file * file, struct vm_area_struct * vma)
268 struct shm_file_data *sfd = shm_file_data(file);
271 ret = sfd->file->f_op->mmap(sfd->file, vma);
274 sfd->vm_ops = vma->vm_ops;
276 BUG_ON(!sfd->vm_ops->fault);
278 vma->vm_ops = &shm_vm_ops;
284 static int shm_release(struct inode *ino, struct file *file)
286 struct shm_file_data *sfd = shm_file_data(file);
289 shm_file_data(file) = NULL;
294 static int shm_fsync(struct file *file, struct dentry *dentry, int datasync)
296 int (*fsync) (struct file *, struct dentry *, int datasync);
297 struct shm_file_data *sfd = shm_file_data(file);
300 fsync = sfd->file->f_op->fsync;
302 ret = fsync(sfd->file, sfd->file->f_path.dentry, datasync);
306 static unsigned long shm_get_unmapped_area(struct file *file,
307 unsigned long addr, unsigned long len, unsigned long pgoff,
310 struct shm_file_data *sfd = shm_file_data(file);
311 return get_unmapped_area(sfd->file, addr, len, pgoff, flags);
314 int is_file_shm_hugepages(struct file *file)
318 if (file->f_op == &shm_file_operations) {
319 struct shm_file_data *sfd;
320 sfd = shm_file_data(file);
321 ret = is_file_hugepages(sfd->file);
326 static const struct file_operations shm_file_operations = {
329 .release = shm_release,
330 .get_unmapped_area = shm_get_unmapped_area,
333 static struct vm_operations_struct shm_vm_ops = {
334 .open = shm_open, /* callback for a new vm-area open */
335 .close = shm_close, /* callback for when the vm-area is released */
337 #if defined(CONFIG_NUMA)
338 .set_policy = shm_set_policy,
339 .get_policy = shm_get_policy,
343 static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
345 key_t key = params->key;
346 int shmflg = params->flg;
347 size_t size = params->u.size;
349 struct shmid_kernel *shp;
350 int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
355 if (size < SHMMIN || size > ns->shm_ctlmax)
358 if (ns->shm_tot + numpages > ns->shm_ctlall)
361 shp = ipc_rcu_alloc(sizeof(*shp));
365 shp->shm_perm.key = key;
366 shp->shm_perm.mode = (shmflg & S_IRWXUGO);
367 shp->mlock_user = NULL;
369 shp->shm_perm.security = NULL;
370 error = security_shm_alloc(shp);
376 sprintf (name, "SYSV%08x", key);
377 if (shmflg & SHM_HUGETLB) {
378 /* hugetlb_file_setup takes care of mlock user accounting */
379 file = hugetlb_file_setup(name, size);
380 shp->mlock_user = current->user;
382 int acctflag = VM_ACCOUNT;
384 * Do not allow no accounting for OVERCOMMIT_NEVER, even
387 if ((shmflg & SHM_NORESERVE) &&
388 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
390 file = shmem_file_setup(name, size, acctflag);
392 error = PTR_ERR(file);
397 id = shm_addid(ns, shp);
401 shp->shm_cprid = task_tgid_vnr(current);
403 shp->shm_atim = shp->shm_dtim = 0;
404 shp->shm_ctim = get_seconds();
405 shp->shm_segsz = size;
407 shp->shm_perm.id = shm_buildid(ns, id, shp->shm_perm.seq);
408 shp->shm_file = file;
410 * shmid gets reported as "inode#" in /proc/pid/maps.
411 * proc-ps tools use this. Changing this will break them.
413 file->f_dentry->d_inode->i_ino = shp->shm_perm.id;
415 ns->shm_tot += numpages;
416 error = shp->shm_perm.id;
423 security_shm_free(shp);
428 static inline int shm_security(void *shp, int shmflg)
430 return security_shm_associate((struct shmid_kernel *) shp, shmflg);
433 static inline int shm_more_checks(void *shp, struct ipc_params *params)
435 if (((struct shmid_kernel *)shp)->shm_segsz < params->u.size)
441 asmlinkage long sys_shmget (key_t key, size_t size, int shmflg)
443 struct ipc_namespace *ns;
444 struct ipc_ops shm_ops;
445 struct ipc_params shm_params;
447 ns = current->nsproxy->ipc_ns;
449 shm_ops.getnew = newseg;
450 shm_ops.associate = shm_security;
451 shm_ops.more_checks = shm_more_checks;
453 shm_params.key = key;
454 shm_params.flg = shmflg;
455 shm_params.u.size = size;
457 return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
460 static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
464 return copy_to_user(buf, in, sizeof(*in));
469 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
470 out.shm_segsz = in->shm_segsz;
471 out.shm_atime = in->shm_atime;
472 out.shm_dtime = in->shm_dtime;
473 out.shm_ctime = in->shm_ctime;
474 out.shm_cpid = in->shm_cpid;
475 out.shm_lpid = in->shm_lpid;
476 out.shm_nattch = in->shm_nattch;
478 return copy_to_user(buf, &out, sizeof(out));
491 static inline unsigned long copy_shmid_from_user(struct shm_setbuf *out, void __user *buf, int version)
496 struct shmid64_ds tbuf;
498 if (copy_from_user(&tbuf, buf, sizeof(tbuf)))
501 out->uid = tbuf.shm_perm.uid;
502 out->gid = tbuf.shm_perm.gid;
503 out->mode = tbuf.shm_perm.mode;
509 struct shmid_ds tbuf_old;
511 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
514 out->uid = tbuf_old.shm_perm.uid;
515 out->gid = tbuf_old.shm_perm.gid;
516 out->mode = tbuf_old.shm_perm.mode;
525 static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
529 return copy_to_user(buf, in, sizeof(*in));
534 if(in->shmmax > INT_MAX)
535 out.shmmax = INT_MAX;
537 out.shmmax = (int)in->shmmax;
539 out.shmmin = in->shmmin;
540 out.shmmni = in->shmmni;
541 out.shmseg = in->shmseg;
542 out.shmall = in->shmall;
544 return copy_to_user(buf, &out, sizeof(out));
551 static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
560 in_use = shm_ids(ns).in_use;
562 for (total = 0, next_id = 0; total < in_use; next_id++) {
563 struct shmid_kernel *shp;
566 shp = shm_get(ns, next_id);
570 inode = shp->shm_file->f_path.dentry->d_inode;
572 if (is_file_hugepages(shp->shm_file)) {
573 struct address_space *mapping = inode->i_mapping;
574 *rss += (HPAGE_SIZE/PAGE_SIZE)*mapping->nrpages;
576 struct shmem_inode_info *info = SHMEM_I(inode);
577 spin_lock(&info->lock);
578 *rss += inode->i_mapping->nrpages;
579 *swp += info->swapped;
580 spin_unlock(&info->lock);
587 asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
589 struct shm_setbuf setbuf;
590 struct shmid_kernel *shp;
592 struct ipc_namespace *ns;
594 if (cmd < 0 || shmid < 0) {
599 version = ipc_parse_version(&cmd);
600 ns = current->nsproxy->ipc_ns;
602 switch (cmd) { /* replace with proc interface ? */
605 struct shminfo64 shminfo;
607 err = security_shm_shmctl(NULL, cmd);
611 memset(&shminfo,0,sizeof(shminfo));
612 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
613 shminfo.shmmax = ns->shm_ctlmax;
614 shminfo.shmall = ns->shm_ctlall;
616 shminfo.shmmin = SHMMIN;
617 if(copy_shminfo_to_user (buf, &shminfo, version))
619 /* reading a integer is always atomic */
620 err = ipc_get_maxid(&shm_ids(ns));
627 struct shm_info shm_info;
629 err = security_shm_shmctl(NULL, cmd);
633 memset(&shm_info,0,sizeof(shm_info));
634 mutex_lock(&shm_ids(ns).mutex);
635 shm_info.used_ids = shm_ids(ns).in_use;
636 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
637 shm_info.shm_tot = ns->shm_tot;
638 shm_info.swap_attempts = 0;
639 shm_info.swap_successes = 0;
640 err = ipc_get_maxid(&shm_ids(ns));
641 mutex_unlock(&shm_ids(ns).mutex);
642 if(copy_to_user (buf, &shm_info, sizeof(shm_info))) {
647 err = err < 0 ? 0 : err;
653 struct shmid64_ds tbuf;
655 memset(&tbuf, 0, sizeof(tbuf));
656 shp = shm_lock(ns, shmid);
660 } else if (cmd == SHM_STAT) {
661 result = shp->shm_perm.id;
663 err = shm_checkid(ns, shp,shmid);
669 if (ipcperms (&shp->shm_perm, S_IRUGO))
671 err = security_shm_shmctl(shp, cmd);
674 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
675 tbuf.shm_segsz = shp->shm_segsz;
676 tbuf.shm_atime = shp->shm_atim;
677 tbuf.shm_dtime = shp->shm_dtim;
678 tbuf.shm_ctime = shp->shm_ctim;
679 tbuf.shm_cpid = shp->shm_cprid;
680 tbuf.shm_lpid = shp->shm_lprid;
681 tbuf.shm_nattch = shp->shm_nattch;
683 if(copy_shmid_to_user (buf, &tbuf, version))
692 shp = shm_lock(ns, shmid);
697 err = shm_checkid(ns, shp,shmid);
701 err = audit_ipc_obj(&(shp->shm_perm));
705 if (!capable(CAP_IPC_LOCK)) {
707 if (current->euid != shp->shm_perm.uid &&
708 current->euid != shp->shm_perm.cuid)
710 if (cmd == SHM_LOCK &&
711 !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur)
715 err = security_shm_shmctl(shp, cmd);
720 struct user_struct * user = current->user;
721 if (!is_file_hugepages(shp->shm_file)) {
722 err = shmem_lock(shp->shm_file, 1, user);
723 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)){
724 shp->shm_perm.mode |= SHM_LOCKED;
725 shp->mlock_user = user;
728 } else if (!is_file_hugepages(shp->shm_file)) {
729 shmem_lock(shp->shm_file, 0, shp->mlock_user);
730 shp->shm_perm.mode &= ~SHM_LOCKED;
731 shp->mlock_user = NULL;
739 * We cannot simply remove the file. The SVID states
740 * that the block remains until the last person
741 * detaches from it, then is deleted. A shmat() on
742 * an RMID segment is legal in older Linux and if
743 * we change it apps break...
745 * Instead we set a destroyed flag, and then blow
746 * the name away when the usage hits zero.
748 mutex_lock(&shm_ids(ns).mutex);
749 shp = shm_lock(ns, shmid);
753 err = shm_checkid(ns, shp, shmid);
757 err = audit_ipc_obj(&(shp->shm_perm));
761 if (current->euid != shp->shm_perm.uid &&
762 current->euid != shp->shm_perm.cuid &&
763 !capable(CAP_SYS_ADMIN)) {
768 err = security_shm_shmctl(shp, cmd);
772 do_shm_rmid(ns, shp);
773 mutex_unlock(&shm_ids(ns).mutex);
779 if (copy_shmid_from_user (&setbuf, buf, version)) {
783 mutex_lock(&shm_ids(ns).mutex);
784 shp = shm_lock(ns, shmid);
788 err = shm_checkid(ns, shp,shmid);
791 err = audit_ipc_obj(&(shp->shm_perm));
794 err = audit_ipc_set_perm(0, setbuf.uid, setbuf.gid, setbuf.mode);
798 if (current->euid != shp->shm_perm.uid &&
799 current->euid != shp->shm_perm.cuid &&
800 !capable(CAP_SYS_ADMIN)) {
804 err = security_shm_shmctl(shp, cmd);
808 shp->shm_perm.uid = setbuf.uid;
809 shp->shm_perm.gid = setbuf.gid;
810 shp->shm_perm.mode = (shp->shm_perm.mode & ~S_IRWXUGO)
811 | (setbuf.mode & S_IRWXUGO);
812 shp->shm_ctim = get_seconds();
825 mutex_unlock(&shm_ids(ns).mutex);
834 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
836 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
837 * "raddr" thing points to kernel space, and there has to be a wrapper around
840 long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
842 struct shmid_kernel *shp;
850 unsigned long user_addr;
851 struct ipc_namespace *ns;
852 struct shm_file_data *sfd;
859 else if ((addr = (ulong)shmaddr)) {
860 if (addr & (SHMLBA-1)) {
861 if (shmflg & SHM_RND)
862 addr &= ~(SHMLBA-1); /* round down */
864 #ifndef __ARCH_FORCE_SHMLBA
865 if (addr & ~PAGE_MASK)
869 flags = MAP_SHARED | MAP_FIXED;
871 if ((shmflg & SHM_REMAP))
877 if (shmflg & SHM_RDONLY) {
882 prot = PROT_READ | PROT_WRITE;
883 acc_mode = S_IRUGO | S_IWUGO;
884 f_mode = FMODE_READ | FMODE_WRITE;
886 if (shmflg & SHM_EXEC) {
892 * We cannot rely on the fs check since SYSV IPC does have an
893 * additional creator id...
895 ns = current->nsproxy->ipc_ns;
896 shp = shm_lock(ns, shmid);
900 err = shm_checkid(ns, shp,shmid);
905 if (ipcperms(&shp->shm_perm, acc_mode))
908 err = security_shm_shmat(shp, shmaddr, shmflg);
912 path.dentry = dget(shp->shm_file->f_path.dentry);
913 path.mnt = shp->shm_file->f_path.mnt;
915 size = i_size_read(path.dentry->d_inode);
919 sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
925 file = alloc_file(path.mnt, path.dentry, f_mode, &shm_file_operations);
929 file->private_data = sfd;
930 file->f_mapping = shp->shm_file->f_mapping;
931 sfd->id = shp->shm_perm.id;
932 sfd->ns = get_ipc_ns(ns);
933 sfd->file = shp->shm_file;
936 down_write(¤t->mm->mmap_sem);
937 if (addr && !(shmflg & SHM_REMAP)) {
939 if (find_vma_intersection(current->mm, addr, addr + size))
942 * If shm segment goes below stack, make sure there is some
943 * space left for the stack to grow (at least 4 pages).
945 if (addr < current->mm->start_stack &&
946 addr > current->mm->start_stack - size - PAGE_SIZE * 5)
950 user_addr = do_mmap (file, addr, size, prot, flags, 0);
953 if (IS_ERR_VALUE(user_addr))
954 err = (long)user_addr;
956 up_write(¤t->mm->mmap_sem);
961 mutex_lock(&shm_ids(ns).mutex);
962 shp = shm_lock(ns, shmid);
965 if(shp->shm_nattch == 0 &&
966 shp->shm_perm.mode & SHM_DEST)
967 shm_destroy(ns, shp);
970 mutex_unlock(&shm_ids(ns).mutex);
986 asmlinkage long sys_shmat(int shmid, char __user *shmaddr, int shmflg)
991 err = do_shmat(shmid, shmaddr, shmflg, &ret);
994 force_successful_syscall_return();
999 * detach and kill segment if marked destroyed.
1000 * The work is done in shm_close.
1002 asmlinkage long sys_shmdt(char __user *shmaddr)
1004 struct mm_struct *mm = current->mm;
1005 struct vm_area_struct *vma, *next;
1006 unsigned long addr = (unsigned long)shmaddr;
1008 int retval = -EINVAL;
1010 if (addr & ~PAGE_MASK)
1013 down_write(&mm->mmap_sem);
1016 * This function tries to be smart and unmap shm segments that
1017 * were modified by partial mlock or munmap calls:
1018 * - It first determines the size of the shm segment that should be
1019 * unmapped: It searches for a vma that is backed by shm and that
1020 * started at address shmaddr. It records it's size and then unmaps
1022 * - Then it unmaps all shm vmas that started at shmaddr and that
1023 * are within the initially determined size.
1024 * Errors from do_munmap are ignored: the function only fails if
1025 * it's called with invalid parameters or if it's called to unmap
1026 * a part of a vma. Both calls in this function are for full vmas,
1027 * the parameters are directly copied from the vma itself and always
1028 * valid - therefore do_munmap cannot fail. (famous last words?)
1031 * If it had been mremap()'d, the starting address would not
1032 * match the usual checks anyway. So assume all vma's are
1033 * above the starting address given.
1035 vma = find_vma(mm, addr);
1038 next = vma->vm_next;
1041 * Check if the starting address would match, i.e. it's
1042 * a fragment created by mprotect() and/or munmap(), or it
1043 * otherwise it starts at this address with no hassles.
1045 if ((vma->vm_ops == &shm_vm_ops) &&
1046 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1049 size = vma->vm_file->f_path.dentry->d_inode->i_size;
1050 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1052 * We discovered the size of the shm segment, so
1053 * break out of here and fall through to the next
1054 * loop that uses the size information to stop
1055 * searching for matching vma's.
1065 * We need look no further than the maximum address a fragment
1066 * could possibly have landed at. Also cast things to loff_t to
1067 * prevent overflows and make comparisions vs. equal-width types.
1069 size = PAGE_ALIGN(size);
1070 while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1071 next = vma->vm_next;
1073 /* finding a matching vma now does not alter retval */
1074 if ((vma->vm_ops == &shm_vm_ops) &&
1075 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1077 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1081 up_write(&mm->mmap_sem);
1085 #ifdef CONFIG_PROC_FS
1086 static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1088 struct shmid_kernel *shp = it;
1091 #define SMALL_STRING "%10d %10d %4o %10u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1092 #define BIG_STRING "%10d %10d %4o %21u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1094 if (sizeof(size_t) <= sizeof(int))
1095 format = SMALL_STRING;
1097 format = BIG_STRING;
1098 return seq_printf(s, format,