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/rwsem.h>
39 #include <linux/nsproxy.h>
40 #include <linux/mount.h>
41 #include <linux/ipc_namespace.h>
43 #include <asm/uaccess.h>
47 struct shm_file_data {
49 struct ipc_namespace *ns;
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 struct vm_operations_struct shm_vm_ops;
59 static struct ipc_ids init_shm_ids;
61 #define shm_ids(ns) (*((ns)->ids[IPC_SHM_IDS]))
63 #define shm_unlock(shp) \
64 ipc_unlock(&(shp)->shm_perm)
65 #define shm_buildid(id, seq) ipc_buildid(id, seq)
67 static int newseg(struct ipc_namespace *, struct ipc_params *);
68 static void shm_open(struct vm_area_struct *vma);
69 static void shm_close(struct vm_area_struct *vma);
70 static void shm_destroy (struct ipc_namespace *ns, struct shmid_kernel *shp);
72 static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
75 static void __shm_init_ns(struct ipc_namespace *ns, struct ipc_ids *ids)
77 ns->ids[IPC_SHM_IDS] = ids;
78 ns->shm_ctlmax = SHMMAX;
79 ns->shm_ctlall = SHMALL;
80 ns->shm_ctlmni = SHMMNI;
86 * Called with shm_ids.rw_mutex (writer) and the shp structure locked.
87 * Only shm_ids.rw_mutex remains locked on exit.
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;
101 int shm_init_ns(struct ipc_namespace *ns)
105 ids = kmalloc(sizeof(struct ipc_ids), GFP_KERNEL);
109 __shm_init_ns(ns, ids);
113 void shm_exit_ns(struct ipc_namespace *ns)
115 struct shmid_kernel *shp;
116 struct kern_ipc_perm *perm;
120 down_write(&shm_ids(ns).rw_mutex);
122 in_use = shm_ids(ns).in_use;
124 for (total = 0, next_id = 0; total < in_use; next_id++) {
125 perm = idr_find(&shm_ids(ns).ipcs_idr, next_id);
128 ipc_lock_by_ptr(perm);
129 shp = container_of(perm, struct shmid_kernel, shm_perm);
130 do_shm_rmid(ns, shp);
133 up_write(&shm_ids(ns).rw_mutex);
135 kfree(ns->ids[IPC_SHM_IDS]);
136 ns->ids[IPC_SHM_IDS] = NULL;
140 void __init shm_init (void)
142 __shm_init_ns(&init_ipc_ns, &init_shm_ids);
143 ipc_init_proc_interface("sysvipc/shm",
144 " key shmid perms size cpid lpid nattch uid gid cuid cgid atime dtime ctime\n",
145 IPC_SHM_IDS, sysvipc_shm_proc_show);
149 * shm_lock_(check_)down routines are called in the paths where the rw_mutex
150 * is held to protect access to the idr tree.
152 static inline struct shmid_kernel *shm_lock_down(struct ipc_namespace *ns,
155 struct kern_ipc_perm *ipcp = ipc_lock_down(&shm_ids(ns), id);
158 return (struct shmid_kernel *)ipcp;
160 return container_of(ipcp, struct shmid_kernel, shm_perm);
163 static inline struct shmid_kernel *shm_lock_check_down(
164 struct ipc_namespace *ns,
167 struct kern_ipc_perm *ipcp = ipc_lock_check_down(&shm_ids(ns), id);
170 return (struct shmid_kernel *)ipcp;
172 return container_of(ipcp, struct shmid_kernel, shm_perm);
176 * shm_lock_(check_) routines are called in the paths where the rw_mutex
179 static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
181 struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id);
184 return (struct shmid_kernel *)ipcp;
186 return container_of(ipcp, struct shmid_kernel, shm_perm);
189 static inline struct shmid_kernel *shm_lock_check(struct ipc_namespace *ns,
192 struct kern_ipc_perm *ipcp = ipc_lock_check(&shm_ids(ns), id);
195 return (struct shmid_kernel *)ipcp;
197 return container_of(ipcp, struct shmid_kernel, shm_perm);
200 static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
202 ipc_rmid(&shm_ids(ns), &s->shm_perm);
205 static inline int shm_addid(struct ipc_namespace *ns, struct shmid_kernel *shp)
207 return ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
212 /* This is called by fork, once for every shm attach. */
213 static void shm_open(struct vm_area_struct *vma)
215 struct file *file = vma->vm_file;
216 struct shm_file_data *sfd = shm_file_data(file);
217 struct shmid_kernel *shp;
219 shp = shm_lock(sfd->ns, sfd->id);
221 shp->shm_atim = get_seconds();
222 shp->shm_lprid = task_tgid_vnr(current);
228 * shm_destroy - free the struct shmid_kernel
231 * @shp: struct to free
233 * It has to be called with shp and shm_ids.rw_mutex (writer) locked,
234 * but returns with shp unlocked and freed.
236 static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
238 ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
241 if (!is_file_hugepages(shp->shm_file))
242 shmem_lock(shp->shm_file, 0, shp->mlock_user);
244 user_shm_unlock(shp->shm_file->f_path.dentry->d_inode->i_size,
246 fput (shp->shm_file);
247 security_shm_free(shp);
252 * remove the attach descriptor vma.
253 * free memory for segment if it is marked destroyed.
254 * The descriptor has already been removed from the current->mm->mmap list
255 * and will later be kfree()d.
257 static void shm_close(struct vm_area_struct *vma)
259 struct file * file = vma->vm_file;
260 struct shm_file_data *sfd = shm_file_data(file);
261 struct shmid_kernel *shp;
262 struct ipc_namespace *ns = sfd->ns;
264 down_write(&shm_ids(ns).rw_mutex);
265 /* remove from the list of attaches of the shm segment */
266 shp = shm_lock_down(ns, sfd->id);
268 shp->shm_lprid = task_tgid_vnr(current);
269 shp->shm_dtim = get_seconds();
271 if(shp->shm_nattch == 0 &&
272 shp->shm_perm.mode & SHM_DEST)
273 shm_destroy(ns, shp);
276 up_write(&shm_ids(ns).rw_mutex);
279 static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
281 struct file *file = vma->vm_file;
282 struct shm_file_data *sfd = shm_file_data(file);
284 return sfd->vm_ops->fault(vma, vmf);
288 static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
290 struct file *file = vma->vm_file;
291 struct shm_file_data *sfd = shm_file_data(file);
293 if (sfd->vm_ops->set_policy)
294 err = sfd->vm_ops->set_policy(vma, new);
298 static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
301 struct file *file = vma->vm_file;
302 struct shm_file_data *sfd = shm_file_data(file);
303 struct mempolicy *pol = NULL;
305 if (sfd->vm_ops->get_policy)
306 pol = sfd->vm_ops->get_policy(vma, addr);
307 else if (vma->vm_policy)
308 pol = vma->vm_policy;
310 pol = current->mempolicy;
315 static int shm_mmap(struct file * file, struct vm_area_struct * vma)
317 struct shm_file_data *sfd = shm_file_data(file);
320 ret = sfd->file->f_op->mmap(sfd->file, vma);
323 sfd->vm_ops = vma->vm_ops;
325 BUG_ON(!sfd->vm_ops->fault);
327 vma->vm_ops = &shm_vm_ops;
333 static int shm_release(struct inode *ino, struct file *file)
335 struct shm_file_data *sfd = shm_file_data(file);
338 shm_file_data(file) = NULL;
343 static int shm_fsync(struct file *file, struct dentry *dentry, int datasync)
345 int (*fsync) (struct file *, struct dentry *, int datasync);
346 struct shm_file_data *sfd = shm_file_data(file);
349 fsync = sfd->file->f_op->fsync;
351 ret = fsync(sfd->file, sfd->file->f_path.dentry, datasync);
355 static unsigned long shm_get_unmapped_area(struct file *file,
356 unsigned long addr, unsigned long len, unsigned long pgoff,
359 struct shm_file_data *sfd = shm_file_data(file);
360 return get_unmapped_area(sfd->file, addr, len, pgoff, flags);
363 int is_file_shm_hugepages(struct file *file)
367 if (file->f_op == &shm_file_operations) {
368 struct shm_file_data *sfd;
369 sfd = shm_file_data(file);
370 ret = is_file_hugepages(sfd->file);
375 static const struct file_operations shm_file_operations = {
378 .release = shm_release,
379 .get_unmapped_area = shm_get_unmapped_area,
382 static struct vm_operations_struct shm_vm_ops = {
383 .open = shm_open, /* callback for a new vm-area open */
384 .close = shm_close, /* callback for when the vm-area is released */
386 #if defined(CONFIG_NUMA)
387 .set_policy = shm_set_policy,
388 .get_policy = shm_get_policy,
393 * newseg - Create a new shared memory segment
395 * @params: ptr to the structure that contains key, size and shmflg
397 * Called with shm_ids.rw_mutex held as a writer.
400 static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
402 key_t key = params->key;
403 int shmflg = params->flg;
404 size_t size = params->u.size;
406 struct shmid_kernel *shp;
407 int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
412 if (size < SHMMIN || size > ns->shm_ctlmax)
415 if (ns->shm_tot + numpages > ns->shm_ctlall)
418 shp = ipc_rcu_alloc(sizeof(*shp));
422 shp->shm_perm.key = key;
423 shp->shm_perm.mode = (shmflg & S_IRWXUGO);
424 shp->mlock_user = NULL;
426 shp->shm_perm.security = NULL;
427 error = security_shm_alloc(shp);
433 sprintf (name, "SYSV%08x", key);
434 if (shmflg & SHM_HUGETLB) {
435 /* hugetlb_file_setup takes care of mlock user accounting */
436 file = hugetlb_file_setup(name, size);
437 shp->mlock_user = current->user;
439 int acctflag = VM_ACCOUNT;
441 * Do not allow no accounting for OVERCOMMIT_NEVER, even
444 if ((shmflg & SHM_NORESERVE) &&
445 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
447 file = shmem_file_setup(name, size, acctflag);
449 error = PTR_ERR(file);
453 id = shm_addid(ns, shp);
459 shp->shm_cprid = task_tgid_vnr(current);
461 shp->shm_atim = shp->shm_dtim = 0;
462 shp->shm_ctim = get_seconds();
463 shp->shm_segsz = size;
465 shp->shm_perm.id = shm_buildid(id, shp->shm_perm.seq);
466 shp->shm_file = file;
468 * shmid gets reported as "inode#" in /proc/pid/maps.
469 * proc-ps tools use this. Changing this will break them.
471 file->f_dentry->d_inode->i_ino = shp->shm_perm.id;
473 ns->shm_tot += numpages;
474 error = shp->shm_perm.id;
481 security_shm_free(shp);
487 * Called with shm_ids.rw_mutex and ipcp locked.
489 static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)
491 struct shmid_kernel *shp;
493 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
494 return security_shm_associate(shp, shmflg);
498 * Called with shm_ids.rw_mutex and ipcp locked.
500 static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
501 struct ipc_params *params)
503 struct shmid_kernel *shp;
505 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
506 if (shp->shm_segsz < params->u.size)
512 asmlinkage long sys_shmget (key_t key, size_t size, int shmflg)
514 struct ipc_namespace *ns;
515 struct ipc_ops shm_ops;
516 struct ipc_params shm_params;
518 ns = current->nsproxy->ipc_ns;
520 shm_ops.getnew = newseg;
521 shm_ops.associate = shm_security;
522 shm_ops.more_checks = shm_more_checks;
524 shm_params.key = key;
525 shm_params.flg = shmflg;
526 shm_params.u.size = size;
528 return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
531 static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
535 return copy_to_user(buf, in, sizeof(*in));
540 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
541 out.shm_segsz = in->shm_segsz;
542 out.shm_atime = in->shm_atime;
543 out.shm_dtime = in->shm_dtime;
544 out.shm_ctime = in->shm_ctime;
545 out.shm_cpid = in->shm_cpid;
546 out.shm_lpid = in->shm_lpid;
547 out.shm_nattch = in->shm_nattch;
549 return copy_to_user(buf, &out, sizeof(out));
562 static inline unsigned long copy_shmid_from_user(struct shm_setbuf *out, void __user *buf, int version)
567 struct shmid64_ds tbuf;
569 if (copy_from_user(&tbuf, buf, sizeof(tbuf)))
572 out->uid = tbuf.shm_perm.uid;
573 out->gid = tbuf.shm_perm.gid;
574 out->mode = tbuf.shm_perm.mode;
580 struct shmid_ds tbuf_old;
582 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
585 out->uid = tbuf_old.shm_perm.uid;
586 out->gid = tbuf_old.shm_perm.gid;
587 out->mode = tbuf_old.shm_perm.mode;
596 static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
600 return copy_to_user(buf, in, sizeof(*in));
605 if(in->shmmax > INT_MAX)
606 out.shmmax = INT_MAX;
608 out.shmmax = (int)in->shmmax;
610 out.shmmin = in->shmmin;
611 out.shmmni = in->shmmni;
612 out.shmseg = in->shmseg;
613 out.shmall = in->shmall;
615 return copy_to_user(buf, &out, sizeof(out));
623 * Called with shm_ids.rw_mutex held as a reader
625 static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
634 in_use = shm_ids(ns).in_use;
636 for (total = 0, next_id = 0; total < in_use; next_id++) {
637 struct shmid_kernel *shp;
640 shp = idr_find(&shm_ids(ns).ipcs_idr, next_id);
644 inode = shp->shm_file->f_path.dentry->d_inode;
646 if (is_file_hugepages(shp->shm_file)) {
647 struct address_space *mapping = inode->i_mapping;
648 *rss += (HPAGE_SIZE/PAGE_SIZE)*mapping->nrpages;
650 struct shmem_inode_info *info = SHMEM_I(inode);
651 spin_lock(&info->lock);
652 *rss += inode->i_mapping->nrpages;
653 *swp += info->swapped;
654 spin_unlock(&info->lock);
661 asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
663 struct shm_setbuf setbuf;
664 struct shmid_kernel *shp;
666 struct ipc_namespace *ns;
668 if (cmd < 0 || shmid < 0) {
673 version = ipc_parse_version(&cmd);
674 ns = current->nsproxy->ipc_ns;
676 switch (cmd) { /* replace with proc interface ? */
679 struct shminfo64 shminfo;
681 err = security_shm_shmctl(NULL, cmd);
685 memset(&shminfo,0,sizeof(shminfo));
686 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
687 shminfo.shmmax = ns->shm_ctlmax;
688 shminfo.shmall = ns->shm_ctlall;
690 shminfo.shmmin = SHMMIN;
691 if(copy_shminfo_to_user (buf, &shminfo, version))
694 down_read(&shm_ids(ns).rw_mutex);
695 err = ipc_get_maxid(&shm_ids(ns));
696 up_read(&shm_ids(ns).rw_mutex);
704 struct shm_info shm_info;
706 err = security_shm_shmctl(NULL, cmd);
710 memset(&shm_info,0,sizeof(shm_info));
711 down_read(&shm_ids(ns).rw_mutex);
712 shm_info.used_ids = shm_ids(ns).in_use;
713 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
714 shm_info.shm_tot = ns->shm_tot;
715 shm_info.swap_attempts = 0;
716 shm_info.swap_successes = 0;
717 err = ipc_get_maxid(&shm_ids(ns));
718 up_read(&shm_ids(ns).rw_mutex);
719 if(copy_to_user (buf, &shm_info, sizeof(shm_info))) {
724 err = err < 0 ? 0 : err;
730 struct shmid64_ds tbuf;
738 if (cmd == SHM_STAT) {
739 shp = shm_lock(ns, shmid);
744 result = shp->shm_perm.id;
746 shp = shm_lock_check(ns, shmid);
754 if (ipcperms (&shp->shm_perm, S_IRUGO))
756 err = security_shm_shmctl(shp, cmd);
759 memset(&tbuf, 0, sizeof(tbuf));
760 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
761 tbuf.shm_segsz = shp->shm_segsz;
762 tbuf.shm_atime = shp->shm_atim;
763 tbuf.shm_dtime = shp->shm_dtim;
764 tbuf.shm_ctime = shp->shm_ctim;
765 tbuf.shm_cpid = shp->shm_cprid;
766 tbuf.shm_lpid = shp->shm_lprid;
767 tbuf.shm_nattch = shp->shm_nattch;
769 if(copy_shmid_to_user (buf, &tbuf, version))
778 shp = shm_lock_check(ns, shmid);
784 err = audit_ipc_obj(&(shp->shm_perm));
788 if (!capable(CAP_IPC_LOCK)) {
790 if (current->euid != shp->shm_perm.uid &&
791 current->euid != shp->shm_perm.cuid)
793 if (cmd == SHM_LOCK &&
794 !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur)
798 err = security_shm_shmctl(shp, cmd);
803 struct user_struct * user = current->user;
804 if (!is_file_hugepages(shp->shm_file)) {
805 err = shmem_lock(shp->shm_file, 1, user);
806 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)){
807 shp->shm_perm.mode |= SHM_LOCKED;
808 shp->mlock_user = user;
811 } else if (!is_file_hugepages(shp->shm_file)) {
812 shmem_lock(shp->shm_file, 0, shp->mlock_user);
813 shp->shm_perm.mode &= ~SHM_LOCKED;
814 shp->mlock_user = NULL;
822 * We cannot simply remove the file. The SVID states
823 * that the block remains until the last person
824 * detaches from it, then is deleted. A shmat() on
825 * an RMID segment is legal in older Linux and if
826 * we change it apps break...
828 * Instead we set a destroyed flag, and then blow
829 * the name away when the usage hits zero.
831 down_write(&shm_ids(ns).rw_mutex);
832 shp = shm_lock_check_down(ns, shmid);
838 err = audit_ipc_obj(&(shp->shm_perm));
842 if (current->euid != shp->shm_perm.uid &&
843 current->euid != shp->shm_perm.cuid &&
844 !capable(CAP_SYS_ADMIN)) {
849 err = security_shm_shmctl(shp, cmd);
853 do_shm_rmid(ns, shp);
854 up_write(&shm_ids(ns).rw_mutex);
865 if (copy_shmid_from_user (&setbuf, buf, version)) {
869 down_write(&shm_ids(ns).rw_mutex);
870 shp = shm_lock_check_down(ns, shmid);
875 err = audit_ipc_obj(&(shp->shm_perm));
878 err = audit_ipc_set_perm(0, setbuf.uid, setbuf.gid, setbuf.mode);
882 if (current->euid != shp->shm_perm.uid &&
883 current->euid != shp->shm_perm.cuid &&
884 !capable(CAP_SYS_ADMIN)) {
888 err = security_shm_shmctl(shp, cmd);
892 shp->shm_perm.uid = setbuf.uid;
893 shp->shm_perm.gid = setbuf.gid;
894 shp->shm_perm.mode = (shp->shm_perm.mode & ~S_IRWXUGO)
895 | (setbuf.mode & S_IRWXUGO);
896 shp->shm_ctim = get_seconds();
909 up_write(&shm_ids(ns).rw_mutex);
918 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
920 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
921 * "raddr" thing points to kernel space, and there has to be a wrapper around
924 long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
926 struct shmid_kernel *shp;
934 unsigned long user_addr;
935 struct ipc_namespace *ns;
936 struct shm_file_data *sfd;
943 else if ((addr = (ulong)shmaddr)) {
944 if (addr & (SHMLBA-1)) {
945 if (shmflg & SHM_RND)
946 addr &= ~(SHMLBA-1); /* round down */
948 #ifndef __ARCH_FORCE_SHMLBA
949 if (addr & ~PAGE_MASK)
953 flags = MAP_SHARED | MAP_FIXED;
955 if ((shmflg & SHM_REMAP))
961 if (shmflg & SHM_RDONLY) {
966 prot = PROT_READ | PROT_WRITE;
967 acc_mode = S_IRUGO | S_IWUGO;
968 f_mode = FMODE_READ | FMODE_WRITE;
970 if (shmflg & SHM_EXEC) {
976 * We cannot rely on the fs check since SYSV IPC does have an
977 * additional creator id...
979 ns = current->nsproxy->ipc_ns;
980 shp = shm_lock_check(ns, shmid);
987 if (ipcperms(&shp->shm_perm, acc_mode))
990 err = security_shm_shmat(shp, shmaddr, shmflg);
994 path.dentry = dget(shp->shm_file->f_path.dentry);
995 path.mnt = shp->shm_file->f_path.mnt;
997 size = i_size_read(path.dentry->d_inode);
1001 sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
1003 goto out_put_dentry;
1007 file = alloc_file(path.mnt, path.dentry, f_mode, &shm_file_operations);
1011 file->private_data = sfd;
1012 file->f_mapping = shp->shm_file->f_mapping;
1013 sfd->id = shp->shm_perm.id;
1014 sfd->ns = get_ipc_ns(ns);
1015 sfd->file = shp->shm_file;
1018 down_write(¤t->mm->mmap_sem);
1019 if (addr && !(shmflg & SHM_REMAP)) {
1021 if (find_vma_intersection(current->mm, addr, addr + size))
1024 * If shm segment goes below stack, make sure there is some
1025 * space left for the stack to grow (at least 4 pages).
1027 if (addr < current->mm->start_stack &&
1028 addr > current->mm->start_stack - size - PAGE_SIZE * 5)
1032 user_addr = do_mmap (file, addr, size, prot, flags, 0);
1035 if (IS_ERR_VALUE(user_addr))
1036 err = (long)user_addr;
1038 up_write(¤t->mm->mmap_sem);
1043 down_write(&shm_ids(ns).rw_mutex);
1044 shp = shm_lock_down(ns, shmid);
1045 BUG_ON(IS_ERR(shp));
1047 if(shp->shm_nattch == 0 &&
1048 shp->shm_perm.mode & SHM_DEST)
1049 shm_destroy(ns, shp);
1052 up_write(&shm_ids(ns).rw_mutex);
1068 asmlinkage long sys_shmat(int shmid, char __user *shmaddr, int shmflg)
1073 err = do_shmat(shmid, shmaddr, shmflg, &ret);
1076 force_successful_syscall_return();
1081 * detach and kill segment if marked destroyed.
1082 * The work is done in shm_close.
1084 asmlinkage long sys_shmdt(char __user *shmaddr)
1086 struct mm_struct *mm = current->mm;
1087 struct vm_area_struct *vma, *next;
1088 unsigned long addr = (unsigned long)shmaddr;
1090 int retval = -EINVAL;
1092 if (addr & ~PAGE_MASK)
1095 down_write(&mm->mmap_sem);
1098 * This function tries to be smart and unmap shm segments that
1099 * were modified by partial mlock or munmap calls:
1100 * - It first determines the size of the shm segment that should be
1101 * unmapped: It searches for a vma that is backed by shm and that
1102 * started at address shmaddr. It records it's size and then unmaps
1104 * - Then it unmaps all shm vmas that started at shmaddr and that
1105 * are within the initially determined size.
1106 * Errors from do_munmap are ignored: the function only fails if
1107 * it's called with invalid parameters or if it's called to unmap
1108 * a part of a vma. Both calls in this function are for full vmas,
1109 * the parameters are directly copied from the vma itself and always
1110 * valid - therefore do_munmap cannot fail. (famous last words?)
1113 * If it had been mremap()'d, the starting address would not
1114 * match the usual checks anyway. So assume all vma's are
1115 * above the starting address given.
1117 vma = find_vma(mm, addr);
1120 next = vma->vm_next;
1123 * Check if the starting address would match, i.e. it's
1124 * a fragment created by mprotect() and/or munmap(), or it
1125 * otherwise it starts at this address with no hassles.
1127 if ((vma->vm_ops == &shm_vm_ops) &&
1128 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1131 size = vma->vm_file->f_path.dentry->d_inode->i_size;
1132 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1134 * We discovered the size of the shm segment, so
1135 * break out of here and fall through to the next
1136 * loop that uses the size information to stop
1137 * searching for matching vma's.
1147 * We need look no further than the maximum address a fragment
1148 * could possibly have landed at. Also cast things to loff_t to
1149 * prevent overflows and make comparisions vs. equal-width types.
1151 size = PAGE_ALIGN(size);
1152 while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1153 next = vma->vm_next;
1155 /* finding a matching vma now does not alter retval */
1156 if ((vma->vm_ops == &shm_vm_ops) &&
1157 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1159 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1163 up_write(&mm->mmap_sem);
1167 #ifdef CONFIG_PROC_FS
1168 static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1170 struct shmid_kernel *shp = it;
1173 #define SMALL_STRING "%10d %10d %4o %10u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1174 #define BIG_STRING "%10d %10d %4o %21u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1176 if (sizeof(size_t) <= sizeof(int))
1177 format = SMALL_STRING;
1179 format = BIG_STRING;
1180 return seq_printf(s, format,