shm.c 26.4 KB
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/*
 * linux/ipc/shm.c
 * Copyright (C) 1992, 1993 Krishna Balasubramanian
 *	 Many improvements/fixes by Bruno Haible.
 * Replaced `struct shm_desc' by `struct vm_area_struct', July 1994.
 * Fixed the shm swap deallocation (shm_unuse()), August 1998 Andrea Arcangeli.
 *
 * /proc/sysvipc/shm support (c) 1999 Dragos Acostachioaie <dragos@iname.com>
 * BIGMEM support, Andrea Arcangeli <andrea@suse.de>
 * SMP thread shm, Jean-Luc Boyard <jean-luc.boyard@siemens.fr>
 * HIGHMEM support, Ingo Molnar <mingo@redhat.com>
 * Make shmmax, shmall, shmmni sysctl'able, Christoph Rohland <cr@sap.com>
 * Shared /dev/zero support, Kanoj Sarcar <kanoj@sgi.com>
 * Move the mm functionality over to mm/shmem.c, Christoph Rohland <cr@sap.com>
 *
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 * support for audit of ipc object properties and permission changes
 * Dustin Kirkland <dustin.kirkland@us.ibm.com>
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 *
 * namespaces support
 * OpenVZ, SWsoft Inc.
 * Pavel Emelianov <xemul@openvz.org>
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 */

#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/hugetlb.h>
#include <linux/shm.h>
#include <linux/init.h>
#include <linux/file.h>
#include <linux/mman.h>
#include <linux/shmem_fs.h>
#include <linux/security.h>
#include <linux/syscalls.h>
#include <linux/audit.h>
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#include <linux/capability.h>
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#include <linux/ptrace.h>
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#include <linux/seq_file.h>
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#include <linux/rwsem.h>
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#include <linux/nsproxy.h>
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#include <linux/mount.h>
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#include <linux/ipc_namespace.h>
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#include <asm/uaccess.h>

#include "util.h"

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struct shm_file_data {
	int id;
	struct ipc_namespace *ns;
	struct file *file;
	const struct vm_operations_struct *vm_ops;
};

#define shm_file_data(file) (*((struct shm_file_data **)&(file)->private_data))

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static const struct file_operations shm_file_operations;
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static struct vm_operations_struct shm_vm_ops;

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#define shm_ids(ns)	((ns)->ids[IPC_SHM_IDS])
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#define shm_unlock(shp)			\
	ipc_unlock(&(shp)->shm_perm)
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static int newseg(struct ipc_namespace *, struct ipc_params *);
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static void shm_open(struct vm_area_struct *vma);
static void shm_close(struct vm_area_struct *vma);
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static void shm_destroy (struct ipc_namespace *ns, struct shmid_kernel *shp);
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#ifdef CONFIG_PROC_FS
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static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
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#endif

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void shm_init_ns(struct ipc_namespace *ns)
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{
	ns->shm_ctlmax = SHMMAX;
	ns->shm_ctlall = SHMALL;
	ns->shm_ctlmni = SHMMNI;
	ns->shm_tot = 0;
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	ipc_init_ids(&ns->ids[IPC_SHM_IDS]);
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}

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/*
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 * Called with shm_ids.rw_mutex (writer) and the shp structure locked.
 * Only shm_ids.rw_mutex remains locked on exit.
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 */
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static void do_shm_rmid(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp)
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{
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	struct shmid_kernel *shp;
	shp = container_of(ipcp, struct shmid_kernel, shm_perm);

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	if (shp->shm_nattch){
		shp->shm_perm.mode |= SHM_DEST;
		/* Do not find it any more */
		shp->shm_perm.key = IPC_PRIVATE;
		shm_unlock(shp);
	} else
		shm_destroy(ns, shp);
}

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#ifdef CONFIG_IPC_NS
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void shm_exit_ns(struct ipc_namespace *ns)
{
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	free_ipcs(ns, &shm_ids(ns), do_shm_rmid);
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}
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#endif
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void __init shm_init (void)
{
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	shm_init_ns(&init_ipc_ns);
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	ipc_init_proc_interface("sysvipc/shm",
				"       key      shmid perms       size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime\n",
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				IPC_SHM_IDS, sysvipc_shm_proc_show);
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}

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/*
 * shm_lock_(check_)down routines are called in the paths where the rw_mutex
 * is held to protect access to the idr tree.
 */
static inline struct shmid_kernel *shm_lock_down(struct ipc_namespace *ns,
						int id)
{
	struct kern_ipc_perm *ipcp = ipc_lock_down(&shm_ids(ns), id);

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	if (IS_ERR(ipcp))
		return (struct shmid_kernel *)ipcp;

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	return container_of(ipcp, struct shmid_kernel, shm_perm);
}

static inline struct shmid_kernel *shm_lock_check_down(
						struct ipc_namespace *ns,
						int id)
{
	struct kern_ipc_perm *ipcp = ipc_lock_check_down(&shm_ids(ns), id);

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	if (IS_ERR(ipcp))
		return (struct shmid_kernel *)ipcp;

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	return container_of(ipcp, struct shmid_kernel, shm_perm);
}

/*
 * shm_lock_(check_) routines are called in the paths where the rw_mutex
 * is not held.
 */
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static inline struct shmid_kernel *shm_lock(struct ipc_namespace *ns, int id)
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{
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	struct kern_ipc_perm *ipcp = ipc_lock(&shm_ids(ns), id);

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	if (IS_ERR(ipcp))
		return (struct shmid_kernel *)ipcp;

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	return container_of(ipcp, struct shmid_kernel, shm_perm);
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}

static inline struct shmid_kernel *shm_lock_check(struct ipc_namespace *ns,
						int id)
{
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	struct kern_ipc_perm *ipcp = ipc_lock_check(&shm_ids(ns), id);

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	if (IS_ERR(ipcp))
		return (struct shmid_kernel *)ipcp;

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	return container_of(ipcp, struct shmid_kernel, shm_perm);
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}

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static inline void shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *s)
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{
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	ipc_rmid(&shm_ids(ns), &s->shm_perm);
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}


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/* This is called by fork, once for every shm attach. */
static void shm_open(struct vm_area_struct *vma)
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{
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	struct file *file = vma->vm_file;
	struct shm_file_data *sfd = shm_file_data(file);
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	struct shmid_kernel *shp;

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	shp = shm_lock(sfd->ns, sfd->id);
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	BUG_ON(IS_ERR(shp));
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	shp->shm_atim = get_seconds();
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	shp->shm_lprid = task_tgid_vnr(current);
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	shp->shm_nattch++;
	shm_unlock(shp);
}

/*
 * shm_destroy - free the struct shmid_kernel
 *
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 * @ns: namespace
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 * @shp: struct to free
 *
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 * It has to be called with shp and shm_ids.rw_mutex (writer) locked,
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 * but returns with shp unlocked and freed.
 */
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static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
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{
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	ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
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	shm_rmid(ns, shp);
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	shm_unlock(shp);
	if (!is_file_hugepages(shp->shm_file))
		shmem_lock(shp->shm_file, 0, shp->mlock_user);
	else
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		user_shm_unlock(shp->shm_file->f_path.dentry->d_inode->i_size,
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						shp->mlock_user);
	fput (shp->shm_file);
	security_shm_free(shp);
	ipc_rcu_putref(shp);
}

/*
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 * remove the attach descriptor vma.
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 * free memory for segment if it is marked destroyed.
 * The descriptor has already been removed from the current->mm->mmap list
 * and will later be kfree()d.
 */
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static void shm_close(struct vm_area_struct *vma)
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{
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	struct file * file = vma->vm_file;
	struct shm_file_data *sfd = shm_file_data(file);
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	struct shmid_kernel *shp;
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	struct ipc_namespace *ns = sfd->ns;
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	down_write(&shm_ids(ns).rw_mutex);
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	/* remove from the list of attaches of the shm segment */
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	shp = shm_lock_down(ns, sfd->id);
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	BUG_ON(IS_ERR(shp));
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	shp->shm_lprid = task_tgid_vnr(current);
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	shp->shm_dtim = get_seconds();
	shp->shm_nattch--;
	if(shp->shm_nattch == 0 &&
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	   shp->shm_perm.mode & SHM_DEST)
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		shm_destroy(ns, shp);
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	else
		shm_unlock(shp);
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	up_write(&shm_ids(ns).rw_mutex);
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}

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static int shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
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{
	struct file *file = vma->vm_file;
	struct shm_file_data *sfd = shm_file_data(file);

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	return sfd->vm_ops->fault(vma, vmf);
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}

#ifdef CONFIG_NUMA
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static int shm_set_policy(struct vm_area_struct *vma, struct mempolicy *new)
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{
	struct file *file = vma->vm_file;
	struct shm_file_data *sfd = shm_file_data(file);
	int err = 0;
	if (sfd->vm_ops->set_policy)
		err = sfd->vm_ops->set_policy(vma, new);
	return err;
}

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static struct mempolicy *shm_get_policy(struct vm_area_struct *vma,
					unsigned long addr)
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{
	struct file *file = vma->vm_file;
	struct shm_file_data *sfd = shm_file_data(file);
	struct mempolicy *pol = NULL;

	if (sfd->vm_ops->get_policy)
		pol = sfd->vm_ops->get_policy(vma, addr);
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	else if (vma->vm_policy)
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		pol = vma->vm_policy;
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	return pol;
}
#endif

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static int shm_mmap(struct file * file, struct vm_area_struct * vma)
{
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	struct shm_file_data *sfd = shm_file_data(file);
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	int ret;

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	ret = sfd->file->f_op->mmap(sfd->file, vma);
	if (ret != 0)
		return ret;
	sfd->vm_ops = vma->vm_ops;
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#ifdef CONFIG_MMU
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	BUG_ON(!sfd->vm_ops->fault);
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#endif
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	vma->vm_ops = &shm_vm_ops;
	shm_open(vma);
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	return ret;
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}

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static int shm_release(struct inode *ino, struct file *file)
{
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	struct shm_file_data *sfd = shm_file_data(file);
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	put_ipc_ns(sfd->ns);
	shm_file_data(file) = NULL;
	kfree(sfd);
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	return 0;
}

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static int shm_fsync(struct file *file, struct dentry *dentry, int datasync)
{
	int (*fsync) (struct file *, struct dentry *, int datasync);
	struct shm_file_data *sfd = shm_file_data(file);
	int ret = -EINVAL;

	fsync = sfd->file->f_op->fsync;
	if (fsync)
		ret = fsync(sfd->file, sfd->file->f_path.dentry, datasync);
	return ret;
}

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static unsigned long shm_get_unmapped_area(struct file *file,
	unsigned long addr, unsigned long len, unsigned long pgoff,
	unsigned long flags)
{
	struct shm_file_data *sfd = shm_file_data(file);
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	return get_unmapped_area(sfd->file, addr, len, pgoff, flags);
}

int is_file_shm_hugepages(struct file *file)
{
	int ret = 0;

	if (file->f_op == &shm_file_operations) {
		struct shm_file_data *sfd;
		sfd = shm_file_data(file);
		ret = is_file_hugepages(sfd->file);
	}
	return ret;
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}

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static const struct file_operations shm_file_operations = {
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	.mmap		= shm_mmap,
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	.fsync		= shm_fsync,
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	.release	= shm_release,
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	.get_unmapped_area	= shm_get_unmapped_area,
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};

static struct vm_operations_struct shm_vm_ops = {
	.open	= shm_open,	/* callback for a new vm-area open */
	.close	= shm_close,	/* callback for when the vm-area is released */
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	.fault	= shm_fault,
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#if defined(CONFIG_NUMA)
	.set_policy = shm_set_policy,
	.get_policy = shm_get_policy,
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#endif
};

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/**
 * newseg - Create a new shared memory segment
 * @ns: namespace
 * @params: ptr to the structure that contains key, size and shmflg
 *
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 * Called with shm_ids.rw_mutex held as a writer.
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 */

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static int newseg(struct ipc_namespace *ns, struct ipc_params *params)
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{
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	key_t key = params->key;
	int shmflg = params->flg;
	size_t size = params->u.size;
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	int error;
	struct shmid_kernel *shp;
	int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
	struct file * file;
	char name[13];
	int id;

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	if (size < SHMMIN || size > ns->shm_ctlmax)
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		return -EINVAL;

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	if (ns->shm_tot + numpages > ns->shm_ctlall)
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		return -ENOSPC;

	shp = ipc_rcu_alloc(sizeof(*shp));
	if (!shp)
		return -ENOMEM;

	shp->shm_perm.key = key;
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	shp->shm_perm.mode = (shmflg & S_IRWXUGO);
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	shp->mlock_user = NULL;

	shp->shm_perm.security = NULL;
	error = security_shm_alloc(shp);
	if (error) {
		ipc_rcu_putref(shp);
		return error;
	}

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	sprintf (name, "SYSV%08x", key);
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	if (shmflg & SHM_HUGETLB) {
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		/* hugetlb_file_setup takes care of mlock user accounting */
		file = hugetlb_file_setup(name, size);
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		shp->mlock_user = current->user;
	} else {
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		int acctflag = VM_ACCOUNT;
		/*
		 * Do not allow no accounting for OVERCOMMIT_NEVER, even
	 	 * if it's asked for.
		 */
		if  ((shmflg & SHM_NORESERVE) &&
				sysctl_overcommit_memory != OVERCOMMIT_NEVER)
			acctflag = 0;
		file = shmem_file_setup(name, size, acctflag);
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	}
	error = PTR_ERR(file);
	if (IS_ERR(file))
		goto no_file;

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	id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
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	if (id < 0) {
		error = id;
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		goto no_id;
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	}
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	shp->shm_cprid = task_tgid_vnr(current);
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	shp->shm_lprid = 0;
	shp->shm_atim = shp->shm_dtim = 0;
	shp->shm_ctim = get_seconds();
	shp->shm_segsz = size;
	shp->shm_nattch = 0;
	shp->shm_file = file;
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	/*
	 * shmid gets reported as "inode#" in /proc/pid/maps.
	 * proc-ps tools use this. Changing this will break them.
	 */
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	file->f_dentry->d_inode->i_ino = shp->shm_perm.id;
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	ns->shm_tot += numpages;
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	error = shp->shm_perm.id;
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	shm_unlock(shp);
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	return error;
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no_id:
	fput(file);
no_file:
	security_shm_free(shp);
	ipc_rcu_putref(shp);
	return error;
}

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/*
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 * Called with shm_ids.rw_mutex and ipcp locked.
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 */
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static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg)
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{
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	struct shmid_kernel *shp;

	shp = container_of(ipcp, struct shmid_kernel, shm_perm);
	return security_shm_associate(shp, shmflg);
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}

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/*
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 * Called with shm_ids.rw_mutex and ipcp locked.
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 */
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static inline int shm_more_checks(struct kern_ipc_perm *ipcp,
				struct ipc_params *params)
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{
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	struct shmid_kernel *shp;

	shp = container_of(ipcp, struct shmid_kernel, shm_perm);
	if (shp->shm_segsz < params->u.size)
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		return -EINVAL;

	return 0;
}

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asmlinkage long sys_shmget (key_t key, size_t size, int shmflg)
{
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	struct ipc_namespace *ns;
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	struct ipc_ops shm_ops;
	struct ipc_params shm_params;
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	ns = current->nsproxy->ipc_ns;
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	shm_ops.getnew = newseg;
	shm_ops.associate = shm_security;
	shm_ops.more_checks = shm_more_checks;
N
Nadia Derbey 已提交
481

N
Nadia Derbey 已提交
482 483 484
	shm_params.key = key;
	shm_params.flg = shmflg;
	shm_params.u.size = size;
L
Linus Torvalds 已提交
485

N
Nadia Derbey 已提交
486
	return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
L
Linus Torvalds 已提交
487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531
}

static inline unsigned long copy_shmid_to_user(void __user *buf, struct shmid64_ds *in, int version)
{
	switch(version) {
	case IPC_64:
		return copy_to_user(buf, in, sizeof(*in));
	case IPC_OLD:
	    {
		struct shmid_ds out;

		ipc64_perm_to_ipc_perm(&in->shm_perm, &out.shm_perm);
		out.shm_segsz	= in->shm_segsz;
		out.shm_atime	= in->shm_atime;
		out.shm_dtime	= in->shm_dtime;
		out.shm_ctime	= in->shm_ctime;
		out.shm_cpid	= in->shm_cpid;
		out.shm_lpid	= in->shm_lpid;
		out.shm_nattch	= in->shm_nattch;

		return copy_to_user(buf, &out, sizeof(out));
	    }
	default:
		return -EINVAL;
	}
}

struct shm_setbuf {
	uid_t	uid;
	gid_t	gid;
	mode_t	mode;
};	

static inline unsigned long copy_shmid_from_user(struct shm_setbuf *out, void __user *buf, int version)
{
	switch(version) {
	case IPC_64:
	    {
		struct shmid64_ds tbuf;

		if (copy_from_user(&tbuf, buf, sizeof(tbuf)))
			return -EFAULT;

		out->uid	= tbuf.shm_perm.uid;
		out->gid	= tbuf.shm_perm.gid;
A
Andrew Morton 已提交
532
		out->mode	= tbuf.shm_perm.mode;
L
Linus Torvalds 已提交
533 534 535 536 537 538 539 540 541 542 543 544

		return 0;
	    }
	case IPC_OLD:
	    {
		struct shmid_ds tbuf_old;

		if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
			return -EFAULT;

		out->uid	= tbuf_old.shm_perm.uid;
		out->gid	= tbuf_old.shm_perm.gid;
A
Andrew Morton 已提交
545
		out->mode	= tbuf_old.shm_perm.mode;
L
Linus Torvalds 已提交
546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579

		return 0;
	    }
	default:
		return -EINVAL;
	}
}

static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminfo64 *in, int version)
{
	switch(version) {
	case IPC_64:
		return copy_to_user(buf, in, sizeof(*in));
	case IPC_OLD:
	    {
		struct shminfo out;

		if(in->shmmax > INT_MAX)
			out.shmmax = INT_MAX;
		else
			out.shmmax = (int)in->shmmax;

		out.shmmin	= in->shmmin;
		out.shmmni	= in->shmmni;
		out.shmseg	= in->shmseg;
		out.shmall	= in->shmall; 

		return copy_to_user(buf, &out, sizeof(out));
	    }
	default:
		return -EINVAL;
	}
}

N
Nadia Derbey 已提交
580
/*
N
Nadia Derbey 已提交
581
 * Called with shm_ids.rw_mutex held as a reader
N
Nadia Derbey 已提交
582
 */
K
Kirill Korotaev 已提交
583 584
static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
		unsigned long *swp)
L
Linus Torvalds 已提交
585
{
N
Nadia Derbey 已提交
586 587
	int next_id;
	int total, in_use;
L
Linus Torvalds 已提交
588 589 590 591

	*rss = 0;
	*swp = 0;

N
Nadia Derbey 已提交
592 593 594
	in_use = shm_ids(ns).in_use;

	for (total = 0, next_id = 0; total < in_use; next_id++) {
L
Linus Torvalds 已提交
595 596 597
		struct shmid_kernel *shp;
		struct inode *inode;

N
Nadia Derbey 已提交
598
		shp = idr_find(&shm_ids(ns).ipcs_idr, next_id);
N
Nadia Derbey 已提交
599
		if (shp == NULL)
L
Linus Torvalds 已提交
600 601
			continue;

J
Josef Sipek 已提交
602
		inode = shp->shm_file->f_path.dentry->d_inode;
L
Linus Torvalds 已提交
603 604 605 606 607 608 609 610 611 612 613

		if (is_file_hugepages(shp->shm_file)) {
			struct address_space *mapping = inode->i_mapping;
			*rss += (HPAGE_SIZE/PAGE_SIZE)*mapping->nrpages;
		} else {
			struct shmem_inode_info *info = SHMEM_I(inode);
			spin_lock(&info->lock);
			*rss += inode->i_mapping->nrpages;
			*swp += info->swapped;
			spin_unlock(&info->lock);
		}
N
Nadia Derbey 已提交
614 615

		total++;
L
Linus Torvalds 已提交
616 617 618
	}
}

619 620 621 622 623 624 625
/*
 * This function handles some shmctl commands which require the rw_mutex
 * to be held in write mode.
 * NOTE: no locks must be held, the rw_mutex is taken inside this function.
 */
static int shmctl_down(struct ipc_namespace *ns, int shmid, int cmd,
		       struct shmid_ds __user *buf, int version)
L
Linus Torvalds 已提交
626
{
627
	struct kern_ipc_perm *ipcp;
L
Linus Torvalds 已提交
628
	struct shm_setbuf setbuf;
629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689
	struct shmid_kernel *shp;
	int err;

	if (cmd == IPC_SET) {
		if (copy_shmid_from_user(&setbuf, buf, version))
			return -EFAULT;
	}

	down_write(&shm_ids(ns).rw_mutex);
	shp = shm_lock_check_down(ns, shmid);
	if (IS_ERR(shp)) {
		err = PTR_ERR(shp);
		goto out_up;
	}

	ipcp = &shp->shm_perm;

	err = audit_ipc_obj(ipcp);
	if (err)
		goto out_unlock;

	if (cmd == IPC_SET) {
		err = audit_ipc_set_perm(0, setbuf.uid,
					 setbuf.gid, setbuf.mode);
		if (err)
			goto out_unlock;
	}

	if (current->euid != ipcp->uid &&
	    current->euid != ipcp->cuid &&
	    !capable(CAP_SYS_ADMIN)) {
		err = -EPERM;
		goto out_unlock;
	}

	err = security_shm_shmctl(shp, cmd);
	if (err)
		goto out_unlock;
	switch (cmd) {
	case IPC_RMID:
		do_shm_rmid(ns, ipcp);
		goto out_up;
	case IPC_SET:
		ipcp->uid = setbuf.uid;
		ipcp->gid = setbuf.gid;
		ipcp->mode = (ipcp->mode & ~S_IRWXUGO)
			| (setbuf.mode & S_IRWXUGO);
		shp->shm_ctim = get_seconds();
		break;
	default:
		err = -EINVAL;
	}
out_unlock:
	shm_unlock(shp);
out_up:
	up_write(&shm_ids(ns).rw_mutex);
	return err;
}

asmlinkage long sys_shmctl(int shmid, int cmd, struct shmid_ds __user *buf)
{
L
Linus Torvalds 已提交
690 691
	struct shmid_kernel *shp;
	int err, version;
K
Kirill Korotaev 已提交
692
	struct ipc_namespace *ns;
L
Linus Torvalds 已提交
693 694 695 696 697 698 699

	if (cmd < 0 || shmid < 0) {
		err = -EINVAL;
		goto out;
	}

	version = ipc_parse_version(&cmd);
K
Kirill Korotaev 已提交
700
	ns = current->nsproxy->ipc_ns;
L
Linus Torvalds 已提交
701 702 703 704 705 706 707 708 709 710 711

	switch (cmd) { /* replace with proc interface ? */
	case IPC_INFO:
	{
		struct shminfo64 shminfo;

		err = security_shm_shmctl(NULL, cmd);
		if (err)
			return err;

		memset(&shminfo,0,sizeof(shminfo));
K
Kirill Korotaev 已提交
712 713 714
		shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
		shminfo.shmmax = ns->shm_ctlmax;
		shminfo.shmall = ns->shm_ctlall;
L
Linus Torvalds 已提交
715 716 717 718

		shminfo.shmmin = SHMMIN;
		if(copy_shminfo_to_user (buf, &shminfo, version))
			return -EFAULT;
N
Nadia Derbey 已提交
719

N
Nadia Derbey 已提交
720
		down_read(&shm_ids(ns).rw_mutex);
N
Nadia Derbey 已提交
721
		err = ipc_get_maxid(&shm_ids(ns));
N
Nadia Derbey 已提交
722
		up_read(&shm_ids(ns).rw_mutex);
N
Nadia Derbey 已提交
723

L
Linus Torvalds 已提交
724 725 726 727 728 729 730 731 732 733 734 735 736
		if(err<0)
			err = 0;
		goto out;
	}
	case SHM_INFO:
	{
		struct shm_info shm_info;

		err = security_shm_shmctl(NULL, cmd);
		if (err)
			return err;

		memset(&shm_info,0,sizeof(shm_info));
N
Nadia Derbey 已提交
737
		down_read(&shm_ids(ns).rw_mutex);
K
Kirill Korotaev 已提交
738 739 740
		shm_info.used_ids = shm_ids(ns).in_use;
		shm_get_stat (ns, &shm_info.shm_rss, &shm_info.shm_swp);
		shm_info.shm_tot = ns->shm_tot;
L
Linus Torvalds 已提交
741 742
		shm_info.swap_attempts = 0;
		shm_info.swap_successes = 0;
N
Nadia Derbey 已提交
743
		err = ipc_get_maxid(&shm_ids(ns));
N
Nadia Derbey 已提交
744
		up_read(&shm_ids(ns).rw_mutex);
L
Linus Torvalds 已提交
745 746 747 748 749 750 751 752 753 754 755 756 757
		if(copy_to_user (buf, &shm_info, sizeof(shm_info))) {
			err = -EFAULT;
			goto out;
		}

		err = err < 0 ? 0 : err;
		goto out;
	}
	case SHM_STAT:
	case IPC_STAT:
	{
		struct shmid64_ds tbuf;
		int result;
758 759 760

		if (!buf) {
			err = -EFAULT;
L
Linus Torvalds 已提交
761
			goto out;
762 763 764 765 766 767 768 769
		}

		if (cmd == SHM_STAT) {
			shp = shm_lock(ns, shmid);
			if (IS_ERR(shp)) {
				err = PTR_ERR(shp);
				goto out;
			}
N
Nadia Derbey 已提交
770
			result = shp->shm_perm.id;
L
Linus Torvalds 已提交
771
		} else {
772 773 774 775 776
			shp = shm_lock_check(ns, shmid);
			if (IS_ERR(shp)) {
				err = PTR_ERR(shp);
				goto out;
			}
L
Linus Torvalds 已提交
777 778 779 780 781 782 783 784
			result = 0;
		}
		err=-EACCES;
		if (ipcperms (&shp->shm_perm, S_IRUGO))
			goto out_unlock;
		err = security_shm_shmctl(shp, cmd);
		if (err)
			goto out_unlock;
785
		memset(&tbuf, 0, sizeof(tbuf));
L
Linus Torvalds 已提交
786 787 788 789 790 791 792
		kernel_to_ipc64_perm(&shp->shm_perm, &tbuf.shm_perm);
		tbuf.shm_segsz	= shp->shm_segsz;
		tbuf.shm_atime	= shp->shm_atim;
		tbuf.shm_dtime	= shp->shm_dtim;
		tbuf.shm_ctime	= shp->shm_ctim;
		tbuf.shm_cpid	= shp->shm_cprid;
		tbuf.shm_lpid	= shp->shm_lprid;
793
		tbuf.shm_nattch	= shp->shm_nattch;
L
Linus Torvalds 已提交
794 795 796 797 798 799 800 801 802 803
		shm_unlock(shp);
		if(copy_shmid_to_user (buf, &tbuf, version))
			err = -EFAULT;
		else
			err = result;
		goto out;
	}
	case SHM_LOCK:
	case SHM_UNLOCK:
	{
804 805 806
		shp = shm_lock_check(ns, shmid);
		if (IS_ERR(shp)) {
			err = PTR_ERR(shp);
L
Linus Torvalds 已提交
807 808 809
			goto out;
		}

S
Steve Grubb 已提交
810 811 812 813
		err = audit_ipc_obj(&(shp->shm_perm));
		if (err)
			goto out_unlock;

L
Linus Torvalds 已提交
814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831
		if (!capable(CAP_IPC_LOCK)) {
			err = -EPERM;
			if (current->euid != shp->shm_perm.uid &&
			    current->euid != shp->shm_perm.cuid)
				goto out_unlock;
			if (cmd == SHM_LOCK &&
			    !current->signal->rlim[RLIMIT_MEMLOCK].rlim_cur)
				goto out_unlock;
		}

		err = security_shm_shmctl(shp, cmd);
		if (err)
			goto out_unlock;
		
		if(cmd==SHM_LOCK) {
			struct user_struct * user = current->user;
			if (!is_file_hugepages(shp->shm_file)) {
				err = shmem_lock(shp->shm_file, 1, user);
832
				if (!err && !(shp->shm_perm.mode & SHM_LOCKED)){
A
Andrew Morton 已提交
833
					shp->shm_perm.mode |= SHM_LOCKED;
L
Linus Torvalds 已提交
834 835 836 837 838
					shp->mlock_user = user;
				}
			}
		} else if (!is_file_hugepages(shp->shm_file)) {
			shmem_lock(shp->shm_file, 0, shp->mlock_user);
A
Andrew Morton 已提交
839
			shp->shm_perm.mode &= ~SHM_LOCKED;
L
Linus Torvalds 已提交
840 841 842 843 844 845 846
			shp->mlock_user = NULL;
		}
		shm_unlock(shp);
		goto out;
	}
	case IPC_RMID:
	case IPC_SET:
847 848
		err = shmctl_down(ns, shmid, cmd, buf, version);
		return err;
L
Linus Torvalds 已提交
849
	default:
850
		return -EINVAL;
L
Linus Torvalds 已提交
851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875
	}

out_unlock:
	shm_unlock(shp);
out:
	return err;
}

/*
 * Fix shmaddr, allocate descriptor, map shm, add attach descriptor to lists.
 *
 * NOTE! Despite the name, this is NOT a direct system call entrypoint. The
 * "raddr" thing points to kernel space, and there has to be a wrapper around
 * this.
 */
long do_shmat(int shmid, char __user *shmaddr, int shmflg, ulong *raddr)
{
	struct shmid_kernel *shp;
	unsigned long addr;
	unsigned long size;
	struct file * file;
	int    err;
	unsigned long flags;
	unsigned long prot;
	int acc_mode;
876
	unsigned long user_addr;
K
Kirill Korotaev 已提交
877
	struct ipc_namespace *ns;
878 879 880
	struct shm_file_data *sfd;
	struct path path;
	mode_t f_mode;
L
Linus Torvalds 已提交
881

882 883
	err = -EINVAL;
	if (shmid < 0)
L
Linus Torvalds 已提交
884
		goto out;
885
	else if ((addr = (ulong)shmaddr)) {
L
Linus Torvalds 已提交
886 887 888 889 890 891 892
		if (addr & (SHMLBA-1)) {
			if (shmflg & SHM_RND)
				addr &= ~(SHMLBA-1);	   /* round down */
			else
#ifndef __ARCH_FORCE_SHMLBA
				if (addr & ~PAGE_MASK)
#endif
893
					goto out;
L
Linus Torvalds 已提交
894 895 896 897
		}
		flags = MAP_SHARED | MAP_FIXED;
	} else {
		if ((shmflg & SHM_REMAP))
898
			goto out;
L
Linus Torvalds 已提交
899 900 901 902 903 904 905

		flags = MAP_SHARED;
	}

	if (shmflg & SHM_RDONLY) {
		prot = PROT_READ;
		acc_mode = S_IRUGO;
906
		f_mode = FMODE_READ;
L
Linus Torvalds 已提交
907 908 909
	} else {
		prot = PROT_READ | PROT_WRITE;
		acc_mode = S_IRUGO | S_IWUGO;
910
		f_mode = FMODE_READ | FMODE_WRITE;
L
Linus Torvalds 已提交
911 912 913 914 915 916 917 918 919 920
	}
	if (shmflg & SHM_EXEC) {
		prot |= PROT_EXEC;
		acc_mode |= S_IXUGO;
	}

	/*
	 * We cannot rely on the fs check since SYSV IPC does have an
	 * additional creator id...
	 */
K
Kirill Korotaev 已提交
921
	ns = current->nsproxy->ipc_ns;
922 923 924
	shp = shm_lock_check(ns, shmid);
	if (IS_ERR(shp)) {
		err = PTR_ERR(shp);
L
Linus Torvalds 已提交
925
		goto out;
926
	}
927 928 929 930

	err = -EACCES;
	if (ipcperms(&shp->shm_perm, acc_mode))
		goto out_unlock;
L
Linus Torvalds 已提交
931 932

	err = security_shm_shmat(shp, shmaddr, shmflg);
933 934 935 936
	if (err)
		goto out_unlock;

	path.dentry = dget(shp->shm_file->f_path.dentry);
937
	path.mnt    = shp->shm_file->f_path.mnt;
L
Linus Torvalds 已提交
938
	shp->shm_nattch++;
939
	size = i_size_read(path.dentry->d_inode);
L
Linus Torvalds 已提交
940 941
	shm_unlock(shp);

942 943 944
	err = -ENOMEM;
	sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
	if (!sfd)
945
		goto out_put_dentry;
946 947

	err = -ENOMEM;
948 949

	file = alloc_file(path.mnt, path.dentry, f_mode, &shm_file_operations);
950 951 952 953 954
	if (!file)
		goto out_free;

	file->private_data = sfd;
	file->f_mapping = shp->shm_file->f_mapping;
N
Nadia Derbey 已提交
955
	sfd->id = shp->shm_perm.id;
956 957 958 959
	sfd->ns = get_ipc_ns(ns);
	sfd->file = shp->shm_file;
	sfd->vm_ops = NULL;

L
Linus Torvalds 已提交
960 961
	down_write(&current->mm->mmap_sem);
	if (addr && !(shmflg & SHM_REMAP)) {
962
		err = -EINVAL;
L
Linus Torvalds 已提交
963 964 965 966 967 968 969 970 971 972 973
		if (find_vma_intersection(current->mm, addr, addr + size))
			goto invalid;
		/*
		 * If shm segment goes below stack, make sure there is some
		 * space left for the stack to grow (at least 4 pages).
		 */
		if (addr < current->mm->start_stack &&
		    addr > current->mm->start_stack - size - PAGE_SIZE * 5)
			goto invalid;
	}
		
974 975 976 977 978
	user_addr = do_mmap (file, addr, size, prot, flags, 0);
	*raddr = user_addr;
	err = 0;
	if (IS_ERR_VALUE(user_addr))
		err = (long)user_addr;
L
Linus Torvalds 已提交
979 980 981
invalid:
	up_write(&current->mm->mmap_sem);

982 983 984
	fput(file);

out_nattch:
N
Nadia Derbey 已提交
985 986
	down_write(&shm_ids(ns).rw_mutex);
	shp = shm_lock_down(ns, shmid);
987
	BUG_ON(IS_ERR(shp));
L
Linus Torvalds 已提交
988 989
	shp->shm_nattch--;
	if(shp->shm_nattch == 0 &&
A
Andrew Morton 已提交
990
	   shp->shm_perm.mode & SHM_DEST)
K
Kirill Korotaev 已提交
991
		shm_destroy(ns, shp);
L
Linus Torvalds 已提交
992 993
	else
		shm_unlock(shp);
N
Nadia Derbey 已提交
994
	up_write(&shm_ids(ns).rw_mutex);
L
Linus Torvalds 已提交
995 996 997

out:
	return err;
998 999 1000 1001 1002 1003 1004

out_unlock:
	shm_unlock(shp);
	goto out;

out_free:
	kfree(sfd);
1005
out_put_dentry:
1006 1007
	dput(path.dentry);
	goto out_nattch;
L
Linus Torvalds 已提交
1008 1009
}

S
Stephen Rothwell 已提交
1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021
asmlinkage long sys_shmat(int shmid, char __user *shmaddr, int shmflg)
{
	unsigned long ret;
	long err;

	err = do_shmat(shmid, shmaddr, shmflg, &ret);
	if (err)
		return err;
	force_successful_syscall_return();
	return (long)ret;
}

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/*
 * detach and kill segment if marked destroyed.
 * The work is done in shm_close.
 */
asmlinkage long sys_shmdt(char __user *shmaddr)
{
	struct mm_struct *mm = current->mm;
	struct vm_area_struct *vma, *next;
	unsigned long addr = (unsigned long)shmaddr;
	loff_t size = 0;
	int retval = -EINVAL;

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	if (addr & ~PAGE_MASK)
		return retval;

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	down_write(&mm->mmap_sem);

	/*
	 * This function tries to be smart and unmap shm segments that
	 * were modified by partial mlock or munmap calls:
	 * - It first determines the size of the shm segment that should be
	 *   unmapped: It searches for a vma that is backed by shm and that
	 *   started at address shmaddr. It records it's size and then unmaps
	 *   it.
	 * - Then it unmaps all shm vmas that started at shmaddr and that
	 *   are within the initially determined size.
	 * Errors from do_munmap are ignored: the function only fails if
	 * it's called with invalid parameters or if it's called to unmap
	 * a part of a vma. Both calls in this function are for full vmas,
	 * the parameters are directly copied from the vma itself and always
	 * valid - therefore do_munmap cannot fail. (famous last words?)
	 */
	/*
	 * If it had been mremap()'d, the starting address would not
	 * match the usual checks anyway. So assume all vma's are
	 * above the starting address given.
	 */
	vma = find_vma(mm, addr);

	while (vma) {
		next = vma->vm_next;

		/*
		 * Check if the starting address would match, i.e. it's
		 * a fragment created by mprotect() and/or munmap(), or it
		 * otherwise it starts at this address with no hassles.
		 */
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		if ((vma->vm_ops == &shm_vm_ops) &&
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			(vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {


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			size = vma->vm_file->f_path.dentry->d_inode->i_size;
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			do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
			/*
			 * We discovered the size of the shm segment, so
			 * break out of here and fall through to the next
			 * loop that uses the size information to stop
			 * searching for matching vma's.
			 */
			retval = 0;
			vma = next;
			break;
		}
		vma = next;
	}

	/*
	 * We need look no further than the maximum address a fragment
	 * could possibly have landed at. Also cast things to loff_t to
	 * prevent overflows and make comparisions vs. equal-width types.
	 */
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	size = PAGE_ALIGN(size);
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	while (vma && (loff_t)(vma->vm_end - addr) <= size) {
		next = vma->vm_next;

		/* finding a matching vma now does not alter retval */
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		if ((vma->vm_ops == &shm_vm_ops) &&
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			(vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff)

			do_munmap(mm, vma->vm_start, vma->vm_end - vma->vm_start);
		vma = next;
	}

	up_write(&mm->mmap_sem);
	return retval;
}

#ifdef CONFIG_PROC_FS
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static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
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{
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	struct shmid_kernel *shp = it;
	char *format;
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#define SMALL_STRING "%10d %10d  %4o %10u %5u %5u  %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"
#define BIG_STRING   "%10d %10d  %4o %21u %5u %5u  %5d %5u %5u %5u %5u %10lu %10lu %10lu\n"

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	if (sizeof(size_t) <= sizeof(int))
		format = SMALL_STRING;
	else
		format = BIG_STRING;
	return seq_printf(s, format,
			  shp->shm_perm.key,
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			  shp->shm_perm.id,
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			  shp->shm_perm.mode,
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			  shp->shm_segsz,
			  shp->shm_cprid,
			  shp->shm_lprid,
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			  shp->shm_nattch,
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			  shp->shm_perm.uid,
			  shp->shm_perm.gid,
			  shp->shm_perm.cuid,
			  shp->shm_perm.cgid,
			  shp->shm_atim,
			  shp->shm_dtim,
			  shp->shm_ctim);
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}
#endif