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>
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_unlock(shp) \
63 ipc_unlock(&(shp)->shm_perm)
64 #define shm_buildid(ns, id, seq) \
65 ipc_buildid(&shm_ids(ns), 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;
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 down_write(&shm_ids(ns).rw_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 up_write(&shm_ids(ns).rw_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);
145 * shm_lock_(check_)down routines are called in the paths where the rw_mutex
146 * is held to protect access to the idr tree.
148 static inline struct shmid_kernel *shm_lock_down(struct ipc_namespace *ns,
151 struct kern_ipc_perm *ipcp = ipc_lock_down(&shm_ids(ns), id);
153 return container_of(ipcp, struct shmid_kernel, shm_perm);
156 static inline struct shmid_kernel *shm_lock_check_down(
157 struct ipc_namespace *ns,
160 struct kern_ipc_perm *ipcp = ipc_lock_check_down(&shm_ids(ns), id);
162 return container_of(ipcp, struct shmid_kernel, shm_perm);
166 * shm_lock_(check_) routines are called in the paths where the rw_mutex
169 static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
171 struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id);
173 return container_of(ipcp, struct shmid_kernel, shm_perm);
176 static inline struct shmid_kernel *shm_lock_check(struct ipc_namespace *ns,
179 struct kern_ipc_perm *ipcp = ipc_lock_check(&shm_ids(ns), id);
181 return container_of(ipcp, struct shmid_kernel, shm_perm);
184 static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
186 ipc_rmid(&shm_ids(ns), &s->shm_perm);
189 static inline int shm_addid(struct ipc_namespace *ns, struct shmid_kernel *shp)
191 return ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
196 /* This is called by fork, once for every shm attach. */
197 static void shm_open(struct vm_area_struct *vma)
199 struct file *file = vma->vm_file;
200 struct shm_file_data *sfd = shm_file_data(file);
201 struct shmid_kernel *shp;
203 shp = shm_lock(sfd->ns, sfd->id);
205 shp->shm_atim = get_seconds();
206 shp->shm_lprid = task_tgid_vnr(current);
212 * shm_destroy - free the struct shmid_kernel
215 * @shp: struct to free
217 * It has to be called with shp and shm_ids.rw_mutex (writer) locked,
218 * but returns with shp unlocked and freed.
220 static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
222 ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
225 if (!is_file_hugepages(shp->shm_file))
226 shmem_lock(shp->shm_file, 0, shp->mlock_user);
228 user_shm_unlock(shp->shm_file->f_path.dentry->d_inode->i_size,
230 fput (shp->shm_file);
231 security_shm_free(shp);
236 * remove the attach descriptor vma.
237 * free memory for segment if it is marked destroyed.
238 * The descriptor has already been removed from the current->mm->mmap list
239 * and will later be kfree()d.
241 static void shm_close(struct vm_area_struct *vma)
243 struct file * file = vma->vm_file;
244 struct shm_file_data *sfd = shm_file_data(file);
245 struct shmid_kernel *shp;
246 struct ipc_namespace *ns = sfd->ns;
248 down_write(&shm_ids(ns).rw_mutex);
249 /* remove from the list of attaches of the shm segment */
250 shp = shm_lock_down(ns, sfd->id);
252 shp->shm_lprid = task_tgid_vnr(current);
253 shp->shm_dtim = get_seconds();
255 if(shp->shm_nattch == 0 &&
256 shp->shm_perm.mode & SHM_DEST)
257 shm_destroy(ns, shp);
260 up_write(&shm_ids(ns).rw_mutex);
263 static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
265 struct file *file = vma->vm_file;
266 struct shm_file_data *sfd = shm_file_data(file);
268 return sfd->vm_ops->fault(vma, vmf);
272 static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
274 struct file *file = vma->vm_file;
275 struct shm_file_data *sfd = shm_file_data(file);
277 if (sfd->vm_ops->set_policy)
278 err = sfd->vm_ops->set_policy(vma, new);
282 static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
285 struct file *file = vma->vm_file;
286 struct shm_file_data *sfd = shm_file_data(file);
287 struct mempolicy *pol = NULL;
289 if (sfd->vm_ops->get_policy)
290 pol = sfd->vm_ops->get_policy(vma, addr);
291 else if (vma->vm_policy)
292 pol = vma->vm_policy;
294 pol = current->mempolicy;
299 static int shm_mmap(struct file * file, struct vm_area_struct * vma)
301 struct shm_file_data *sfd = shm_file_data(file);
304 ret = sfd->file->f_op->mmap(sfd->file, vma);
307 sfd->vm_ops = vma->vm_ops;
309 BUG_ON(!sfd->vm_ops->fault);
311 vma->vm_ops = &shm_vm_ops;
317 static int shm_release(struct inode *ino, struct file *file)
319 struct shm_file_data *sfd = shm_file_data(file);
322 shm_file_data(file) = NULL;
327 static int shm_fsync(struct file *file, struct dentry *dentry, int datasync)
329 int (*fsync) (struct file *, struct dentry *, int datasync);
330 struct shm_file_data *sfd = shm_file_data(file);
333 fsync = sfd->file->f_op->fsync;
335 ret = fsync(sfd->file, sfd->file->f_path.dentry, datasync);
339 static unsigned long shm_get_unmapped_area(struct file *file,
340 unsigned long addr, unsigned long len, unsigned long pgoff,
343 struct shm_file_data *sfd = shm_file_data(file);
344 return get_unmapped_area(sfd->file, addr, len, pgoff, flags);
347 int is_file_shm_hugepages(struct file *file)
351 if (file->f_op == &shm_file_operations) {
352 struct shm_file_data *sfd;
353 sfd = shm_file_data(file);
354 ret = is_file_hugepages(sfd->file);
359 static const struct file_operations shm_file_operations = {
362 .release = shm_release,
363 .get_unmapped_area = shm_get_unmapped_area,
366 static struct vm_operations_struct shm_vm_ops = {
367 .open = shm_open, /* callback for a new vm-area open */
368 .close = shm_close, /* callback for when the vm-area is released */
370 #if defined(CONFIG_NUMA)
371 .set_policy = shm_set_policy,
372 .get_policy = shm_get_policy,
377 * newseg - Create a new shared memory segment
379 * @params: ptr to the structure that contains key, size and shmflg
381 * Called with shm_ids.rw_mutex held as a writer.
384 static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
386 key_t key = params->key;
387 int shmflg = params->flg;
388 size_t size = params->u.size;
390 struct shmid_kernel *shp;
391 int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
396 if (size < SHMMIN || size > ns->shm_ctlmax)
399 if (ns->shm_tot + numpages > ns->shm_ctlall)
402 shp = ipc_rcu_alloc(sizeof(*shp));
406 shp->shm_perm.key = key;
407 shp->shm_perm.mode = (shmflg & S_IRWXUGO);
408 shp->mlock_user = NULL;
410 shp->shm_perm.security = NULL;
411 error = security_shm_alloc(shp);
417 sprintf (name, "SYSV%08x", key);
418 if (shmflg & SHM_HUGETLB) {
419 /* hugetlb_file_setup takes care of mlock user accounting */
420 file = hugetlb_file_setup(name, size);
421 shp->mlock_user = current->user;
423 int acctflag = VM_ACCOUNT;
425 * Do not allow no accounting for OVERCOMMIT_NEVER, even
428 if ((shmflg & SHM_NORESERVE) &&
429 sysctl_overcommit_memory != OVERCOMMIT_NEVER)
431 file = shmem_file_setup(name, size, acctflag);
433 error = PTR_ERR(file);
438 id = shm_addid(ns, shp);
442 shp->shm_cprid = task_tgid_vnr(current);
444 shp->shm_atim = shp->shm_dtim = 0;
445 shp->shm_ctim = get_seconds();
446 shp->shm_segsz = size;
448 shp->shm_perm.id = shm_buildid(ns, id, shp->shm_perm.seq);
449 shp->shm_file = file;
451 * shmid gets reported as "inode#" in /proc/pid/maps.
452 * proc-ps tools use this. Changing this will break them.
454 file->f_dentry->d_inode->i_ino = shp->shm_perm.id;
456 ns->shm_tot += numpages;
457 error = shp->shm_perm.id;
464 security_shm_free(shp);
470 * Called with shm_ids.rw_mutex and ipcp locked.
472 static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)
474 struct shmid_kernel *shp;
476 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
477 return security_shm_associate(shp, shmflg);
481 * Called with shm_ids.rw_mutex and ipcp locked.
483 static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
484 struct ipc_params *params)
486 struct shmid_kernel *shp;
488 shp = container_of(ipcp, struct shmid_kernel, shm_perm);
489 if (shp->shm_segsz < params->u.size)
495 asmlinkage long sys_shmget (key_t key, size_t size, int shmflg)
497 struct ipc_namespace *ns;
498 struct ipc_ops shm_ops;
499 struct ipc_params shm_params;
501 ns = current->nsproxy->ipc_ns;
503 shm_ops.getnew = newseg;
504 shm_ops.associate = shm_security;
505 shm_ops.more_checks = shm_more_checks;
507 shm_params.key = key;
508 shm_params.flg = shmflg;
509 shm_params.u.size = size;
511 return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
514 static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
518 return copy_to_user(buf, in, sizeof(*in));
523 ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
524 out.shm_segsz = in->shm_segsz;
525 out.shm_atime = in->shm_atime;
526 out.shm_dtime = in->shm_dtime;
527 out.shm_ctime = in->shm_ctime;
528 out.shm_cpid = in->shm_cpid;
529 out.shm_lpid = in->shm_lpid;
530 out.shm_nattch = in->shm_nattch;
532 return copy_to_user(buf, &out, sizeof(out));
545 static inline unsigned long copy_shmid_from_user(struct shm_setbuf *out, void __user *buf, int version)
550 struct shmid64_ds tbuf;
552 if (copy_from_user(&tbuf, buf, sizeof(tbuf)))
555 out->uid = tbuf.shm_perm.uid;
556 out->gid = tbuf.shm_perm.gid;
557 out->mode = tbuf.shm_perm.mode;
563 struct shmid_ds tbuf_old;
565 if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
568 out->uid = tbuf_old.shm_perm.uid;
569 out->gid = tbuf_old.shm_perm.gid;
570 out->mode = tbuf_old.shm_perm.mode;
579 static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
583 return copy_to_user(buf, in, sizeof(*in));
588 if(in->shmmax > INT_MAX)
589 out.shmmax = INT_MAX;
591 out.shmmax = (int)in->shmmax;
593 out.shmmin = in->shmmin;
594 out.shmmni = in->shmmni;
595 out.shmseg = in->shmseg;
596 out.shmall = in->shmall;
598 return copy_to_user(buf, &out, sizeof(out));
606 * Called with shm_ids.rw_mutex held as a reader
608 static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
617 in_use = shm_ids(ns).in_use;
619 for (total = 0, next_id = 0; total < in_use; next_id++) {
620 struct shmid_kernel *shp;
623 shp = idr_find(&shm_ids(ns).ipcs_idr, next_id);
627 inode = shp->shm_file->f_path.dentry->d_inode;
629 if (is_file_hugepages(shp->shm_file)) {
630 struct address_space *mapping = inode->i_mapping;
631 *rss += (HPAGE_SIZE/PAGE_SIZE)*mapping->nrpages;
633 struct shmem_inode_info *info = SHMEM_I(inode);
634 spin_lock(&info->lock);
635 *rss += inode->i_mapping->nrpages;
636 *swp += info->swapped;
637 spin_unlock(&info->lock);
644 asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
646 struct shm_setbuf setbuf;
647 struct shmid_kernel *shp;
649 struct ipc_namespace *ns;
651 if (cmd < 0 || shmid < 0) {
656 version = ipc_parse_version(&cmd);
657 ns = current->nsproxy->ipc_ns;
659 switch (cmd) { /* replace with proc interface ? */
662 struct shminfo64 shminfo;
664 err = security_shm_shmctl(NULL, cmd);
668 memset(&shminfo,0,sizeof(shminfo));
669 shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
670 shminfo.shmmax = ns->shm_ctlmax;
671 shminfo.shmall = ns->shm_ctlall;
673 shminfo.shmmin = SHMMIN;
674 if(copy_shminfo_to_user (buf, &shminfo, version))
677 down_read(&shm_ids(ns).rw_mutex);
678 err = ipc_get_maxid(&shm_ids(ns));
679 up_read(&shm_ids(ns).rw_mutex);
687 struct shm_info shm_info;
689 err = security_shm_shmctl(NULL, cmd);
693 memset(&shm_info,0,sizeof(shm_info));
694 down_read(&shm_ids(ns).rw_mutex);
695 shm_info.used_ids = shm_ids(ns).in_use;
696 shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
697 shm_info.shm_tot = ns->shm_tot;
698 shm_info.swap_attempts = 0;
699 shm_info.swap_successes = 0;
700 err = ipc_get_maxid(&shm_ids(ns));
701 up_read(&shm_ids(ns).rw_mutex);
702 if(copy_to_user (buf, &shm_info, sizeof(shm_info))) {
707 err = err < 0 ? 0 : err;
713 struct shmid64_ds tbuf;
721 if (cmd == SHM_STAT) {
722 shp = shm_lock(ns, shmid);
727 result = shp->shm_perm.id;
729 shp = shm_lock_check(ns, shmid);
737 if (ipcperms (&shp->shm_perm, S_IRUGO))
739 err = security_shm_shmctl(shp, cmd);
742 memset(&tbuf, 0, sizeof(tbuf));
743 kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
744 tbuf.shm_segsz = shp->shm_segsz;
745 tbuf.shm_atime = shp->shm_atim;
746 tbuf.shm_dtime = shp->shm_dtim;
747 tbuf.shm_ctime = shp->shm_ctim;
748 tbuf.shm_cpid = shp->shm_cprid;
749 tbuf.shm_lpid = shp->shm_lprid;
750 tbuf.shm_nattch = shp->shm_nattch;
752 if(copy_shmid_to_user (buf, &tbuf, version))
761 shp = shm_lock_check(ns, shmid);
767 err = audit_ipc_obj(&(shp->shm_perm));
771 if (!capable(CAP_IPC_LOCK)) {
773 if (current->euid != shp->shm_perm.uid &&
774 current->euid != shp->shm_perm.cuid)
776 if (cmd == SHM_LOCK &&
777 !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur)
781 err = security_shm_shmctl(shp, cmd);
786 struct user_struct * user = current->user;
787 if (!is_file_hugepages(shp->shm_file)) {
788 err = shmem_lock(shp->shm_file, 1, user);
789 if (!err && !(shp->shm_perm.mode & SHM_LOCKED)){
790 shp->shm_perm.mode |= SHM_LOCKED;
791 shp->mlock_user = user;
794 } else if (!is_file_hugepages(shp->shm_file)) {
795 shmem_lock(shp->shm_file, 0, shp->mlock_user);
796 shp->shm_perm.mode &= ~SHM_LOCKED;
797 shp->mlock_user = NULL;
805 * We cannot simply remove the file. The SVID states
806 * that the block remains until the last person
807 * detaches from it, then is deleted. A shmat() on
808 * an RMID segment is legal in older Linux and if
809 * we change it apps break...
811 * Instead we set a destroyed flag, and then blow
812 * the name away when the usage hits zero.
814 down_write(&shm_ids(ns).rw_mutex);
815 shp = shm_lock_check_down(ns, shmid);
821 err = audit_ipc_obj(&(shp->shm_perm));
825 if (current->euid != shp->shm_perm.uid &&
826 current->euid != shp->shm_perm.cuid &&
827 !capable(CAP_SYS_ADMIN)) {
832 err = security_shm_shmctl(shp, cmd);
836 do_shm_rmid(ns, shp);
837 up_write(&shm_ids(ns).rw_mutex);
848 if (copy_shmid_from_user (&setbuf, buf, version)) {
852 down_write(&shm_ids(ns).rw_mutex);
853 shp = shm_lock_check_down(ns, shmid);
858 err = audit_ipc_obj(&(shp->shm_perm));
861 err = audit_ipc_set_perm(0, setbuf.uid, setbuf.gid, setbuf.mode);
865 if (current->euid != shp->shm_perm.uid &&
866 current->euid != shp->shm_perm.cuid &&
867 !capable(CAP_SYS_ADMIN)) {
871 err = security_shm_shmctl(shp, cmd);
875 shp->shm_perm.uid = setbuf.uid;
876 shp->shm_perm.gid = setbuf.gid;
877 shp->shm_perm.mode = (shp->shm_perm.mode & ~S_IRWXUGO)
878 | (setbuf.mode & S_IRWXUGO);
879 shp->shm_ctim = get_seconds();
892 up_write(&shm_ids(ns).rw_mutex);
901 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
903 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
904 * "raddr" thing points to kernel space, and there has to be a wrapper around
907 long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
909 struct shmid_kernel *shp;
917 unsigned long user_addr;
918 struct ipc_namespace *ns;
919 struct shm_file_data *sfd;
926 else if ((addr = (ulong)shmaddr)) {
927 if (addr & (SHMLBA-1)) {
928 if (shmflg & SHM_RND)
929 addr &= ~(SHMLBA-1); /* round down */
931 #ifndef __ARCH_FORCE_SHMLBA
932 if (addr & ~PAGE_MASK)
936 flags = MAP_SHARED | MAP_FIXED;
938 if ((shmflg & SHM_REMAP))
944 if (shmflg & SHM_RDONLY) {
949 prot = PROT_READ | PROT_WRITE;
950 acc_mode = S_IRUGO | S_IWUGO;
951 f_mode = FMODE_READ | FMODE_WRITE;
953 if (shmflg & SHM_EXEC) {
959 * We cannot rely on the fs check since SYSV IPC does have an
960 * additional creator id...
962 ns = current->nsproxy->ipc_ns;
963 shp = shm_lock_check(ns, shmid);
970 if (ipcperms(&shp->shm_perm, acc_mode))
973 err = security_shm_shmat(shp, shmaddr, shmflg);
977 path.dentry = dget(shp->shm_file->f_path.dentry);
978 path.mnt = shp->shm_file->f_path.mnt;
980 size = i_size_read(path.dentry->d_inode);
984 sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
990 file = alloc_file(path.mnt, path.dentry, f_mode, &shm_file_operations);
994 file->private_data = sfd;
995 file->f_mapping = shp->shm_file->f_mapping;
996 sfd->id = shp->shm_perm.id;
997 sfd->ns = get_ipc_ns(ns);
998 sfd->file = shp->shm_file;
1001 down_write(¤t->mm->mmap_sem);
1002 if (addr && !(shmflg & SHM_REMAP)) {
1004 if (find_vma_intersection(current->mm, addr, addr + size))
1007 * If shm segment goes below stack, make sure there is some
1008 * space left for the stack to grow (at least 4 pages).
1010 if (addr < current->mm->start_stack &&
1011 addr > current->mm->start_stack - size - PAGE_SIZE * 5)
1015 user_addr = do_mmap (file, addr, size, prot, flags, 0);
1018 if (IS_ERR_VALUE(user_addr))
1019 err = (long)user_addr;
1021 up_write(¤t->mm->mmap_sem);
1026 down_write(&shm_ids(ns).rw_mutex);
1027 shp = shm_lock_down(ns, shmid);
1028 BUG_ON(IS_ERR(shp));
1030 if(shp->shm_nattch == 0 &&
1031 shp->shm_perm.mode & SHM_DEST)
1032 shm_destroy(ns, shp);
1035 up_write(&shm_ids(ns).rw_mutex);
1051 asmlinkage long sys_shmat(int shmid, char __user *shmaddr, int shmflg)
1056 err = do_shmat(shmid, shmaddr, shmflg, &ret);
1059 force_successful_syscall_return();
1064 * detach and kill segment if marked destroyed.
1065 * The work is done in shm_close.
1067 asmlinkage long sys_shmdt(char __user *shmaddr)
1069 struct mm_struct *mm = current->mm;
1070 struct vm_area_struct *vma, *next;
1071 unsigned long addr = (unsigned long)shmaddr;
1073 int retval = -EINVAL;
1075 if (addr & ~PAGE_MASK)
1078 down_write(&mm->mmap_sem);
1081 * This function tries to be smart and unmap shm segments that
1082 * were modified by partial mlock or munmap calls:
1083 * - It first determines the size of the shm segment that should be
1084 * unmapped: It searches for a vma that is backed by shm and that
1085 * started at address shmaddr. It records it's size and then unmaps
1087 * - Then it unmaps all shm vmas that started at shmaddr and that
1088 * are within the initially determined size.
1089 * Errors from do_munmap are ignored: the function only fails if
1090 * it's called with invalid parameters or if it's called to unmap
1091 * a part of a vma. Both calls in this function are for full vmas,
1092 * the parameters are directly copied from the vma itself and always
1093 * valid - therefore do_munmap cannot fail. (famous last words?)
1096 * If it had been mremap()'d, the starting address would not
1097 * match the usual checks anyway. So assume all vma's are
1098 * above the starting address given.
1100 vma = find_vma(mm, addr);
1103 next = vma->vm_next;
1106 * Check if the starting address would match, i.e. it's
1107 * a fragment created by mprotect() and/or munmap(), or it
1108 * otherwise it starts at this address with no hassles.
1110 if ((vma->vm_ops == &shm_vm_ops) &&
1111 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
1114 size = vma->vm_file->f_path.dentry->d_inode->i_size;
1115 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1117 * We discovered the size of the shm segment, so
1118 * break out of here and fall through to the next
1119 * loop that uses the size information to stop
1120 * searching for matching vma's.
1130 * We need look no further than the maximum address a fragment
1131 * could possibly have landed at. Also cast things to loff_t to
1132 * prevent overflows and make comparisions vs. equal-width types.
1134 size = PAGE_ALIGN(size);
1135 while (vma && (loff_t)(vma->vm_end - addr) <= size) {
1136 next = vma->vm_next;
1138 /* finding a matching vma now does not alter retval */
1139 if ((vma->vm_ops == &shm_vm_ops) &&
1140 (vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)
1142 do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
1146 up_write(&mm->mmap_sem);
1150 #ifdef CONFIG_PROC_FS
1151 static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
1153 struct shmid_kernel *shp = it;
1156 #define SMALL_STRING "%10d %10d %4o %10u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1157 #define BIG_STRING "%10d %10d %4o %21u %5u %5u %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
1159 if (sizeof(size_t) <= sizeof(int))
1160 format = SMALL_STRING;
1162 format = BIG_STRING;
1163 return seq_printf(s, format,