shm.c 25.1 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_) routines are called in the paths where the rw_mutex
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 * is not necessarily held.
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 */
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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(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;
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	shm_params.key = key;
	shm_params.flg = shmflg;
	shm_params.u.size = size;
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	return ipcget(ns, &shm_ids(ns), &shm_ops, &shm_params);
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}

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;
	}
}

487 488
static inline unsigned long
copy_shmid_from_user(struct shmid64_ds *out, void __user *buf, int version)
L
Linus Torvalds 已提交
489 490 491
{
	switch(version) {
	case IPC_64:
492
		if (copy_from_user(out, buf, sizeof(*out)))
L
Linus Torvalds 已提交
493 494 495 496 497 498 499 500 501
			return -EFAULT;
		return 0;
	case IPC_OLD:
	    {
		struct shmid_ds tbuf_old;

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

502 503 504
		out->shm_perm.uid	= tbuf_old.shm_perm.uid;
		out->shm_perm.gid	= tbuf_old.shm_perm.gid;
		out->shm_perm.mode	= tbuf_old.shm_perm.mode;
L
Linus Torvalds 已提交
505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538

		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
539
/*
N
Nadia Derbey 已提交
540
 * Called with shm_ids.rw_mutex held as a reader
N
Nadia Derbey 已提交
541
 */
K
Kirill Korotaev 已提交
542 543
static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
		unsigned long *swp)
L
Linus Torvalds 已提交
544
{
N
Nadia Derbey 已提交
545 546
	int next_id;
	int total, in_use;
L
Linus Torvalds 已提交
547 548 549 550

	*rss = 0;
	*swp = 0;

N
Nadia Derbey 已提交
551 552 553
	in_use = shm_ids(ns).in_use;

	for (total = 0, next_id = 0; total < in_use; next_id++) {
L
Linus Torvalds 已提交
554 555 556
		struct shmid_kernel *shp;
		struct inode *inode;

N
Nadia Derbey 已提交
557
		shp = idr_find(&shm_ids(ns).ipcs_idr, next_id);
N
Nadia Derbey 已提交
558
		if (shp == NULL)
L
Linus Torvalds 已提交
559 560
			continue;

J
Josef Sipek 已提交
561
		inode = shp->shm_file->f_path.dentry->d_inode;
L
Linus Torvalds 已提交
562 563 564

		if (is_file_hugepages(shp->shm_file)) {
			struct address_space *mapping = inode->i_mapping;
565 566
			struct hstate *h = hstate_file(shp->shm_file);
			*rss += pages_per_huge_page(h) * mapping->nrpages;
L
Linus Torvalds 已提交
567 568 569 570 571 572 573
		} 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
574 575

		total++;
L
Linus Torvalds 已提交
576 577 578
	}
}

579 580 581 582 583 584 585
/*
 * 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
586
{
587
	struct kern_ipc_perm *ipcp;
588
	struct shmid64_ds shmid64;
589 590 591 592
	struct shmid_kernel *shp;
	int err;

	if (cmd == IPC_SET) {
593
		if (copy_shmid_from_user(&shmid64, buf, version))
594 595 596
			return -EFAULT;
	}

597 598 599
	ipcp = ipcctl_pre_down(&shm_ids(ns), shmid, cmd, &shmid64.shm_perm, 0);
	if (IS_ERR(ipcp))
		return PTR_ERR(ipcp);
600

601
	shp = container_of(ipcp, struct shmid_kernel, shm_perm);
602 603 604 605 606 607 608 609 610

	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:
611
		ipc_update_perm(&shmid64.shm_perm, ipcp);
612 613 614 615 616 617 618 619 620 621 622 623 624 625
		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
626 627
	struct shmid_kernel *shp;
	int err, version;
K
Kirill Korotaev 已提交
628
	struct ipc_namespace *ns;
L
Linus Torvalds 已提交
629 630 631 632 633 634 635

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

	version = ipc_parse_version(&cmd);
K
Kirill Korotaev 已提交
636
	ns = current->nsproxy->ipc_ns;
L
Linus Torvalds 已提交
637 638 639 640 641 642 643 644 645 646 647

	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
648 649 650
		shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
		shminfo.shmmax = ns->shm_ctlmax;
		shminfo.shmall = ns->shm_ctlall;
L
Linus Torvalds 已提交
651 652 653 654

		shminfo.shmmin = SHMMIN;
		if(copy_shminfo_to_user (buf, &shminfo, version))
			return -EFAULT;
N
Nadia Derbey 已提交
655

N
Nadia Derbey 已提交
656
		down_read(&shm_ids(ns).rw_mutex);
N
Nadia Derbey 已提交
657
		err = ipc_get_maxid(&shm_ids(ns));
N
Nadia Derbey 已提交
658
		up_read(&shm_ids(ns).rw_mutex);
N
Nadia Derbey 已提交
659

L
Linus Torvalds 已提交
660 661 662 663 664 665 666 667 668 669 670 671 672
		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
673
		down_read(&shm_ids(ns).rw_mutex);
K
Kirill Korotaev 已提交
674 675 676
		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
677 678
		shm_info.swap_attempts = 0;
		shm_info.swap_successes = 0;
N
Nadia Derbey 已提交
679
		err = ipc_get_maxid(&shm_ids(ns));
N
Nadia Derbey 已提交
680
		up_read(&shm_ids(ns).rw_mutex);
L
Linus Torvalds 已提交
681 682 683 684 685 686 687 688 689 690 691 692 693
		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;
694 695 696

		if (!buf) {
			err = -EFAULT;
L
Linus Torvalds 已提交
697
			goto out;
698 699 700 701 702 703 704 705
		}

		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
706
			result = shp->shm_perm.id;
L
Linus Torvalds 已提交
707
		} else {
708 709 710 711 712
			shp = shm_lock_check(ns, shmid);
			if (IS_ERR(shp)) {
				err = PTR_ERR(shp);
				goto out;
			}
L
Linus Torvalds 已提交
713 714 715 716 717 718 719 720
			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;
721
		memset(&tbuf, 0, sizeof(tbuf));
L
Linus Torvalds 已提交
722 723 724 725 726 727 728
		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;
729
		tbuf.shm_nattch	= shp->shm_nattch;
L
Linus Torvalds 已提交
730 731 732 733 734 735 736 737 738 739
		shm_unlock(shp);
		if(copy_shmid_to_user (buf, &tbuf, version))
			err = -EFAULT;
		else
			err = result;
		goto out;
	}
	case SHM_LOCK:
	case SHM_UNLOCK:
	{
740 741 742
		shp = shm_lock_check(ns, shmid);
		if (IS_ERR(shp)) {
			err = PTR_ERR(shp);
L
Linus Torvalds 已提交
743 744 745
			goto out;
		}

S
Steve Grubb 已提交
746 747 748 749
		err = audit_ipc_obj(&(shp->shm_perm));
		if (err)
			goto out_unlock;

L
Linus Torvalds 已提交
750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767
		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);
768
				if (!err && !(shp->shm_perm.mode & SHM_LOCKED)){
A
Andrew Morton 已提交
769
					shp->shm_perm.mode |= SHM_LOCKED;
L
Linus Torvalds 已提交
770 771 772 773 774
					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
775
			shp->shm_perm.mode &= ~SHM_LOCKED;
L
Linus Torvalds 已提交
776 777 778 779 780 781 782
			shp->mlock_user = NULL;
		}
		shm_unlock(shp);
		goto out;
	}
	case IPC_RMID:
	case IPC_SET:
783 784
		err = shmctl_down(ns, shmid, cmd, buf, version);
		return err;
L
Linus Torvalds 已提交
785
	default:
786
		return -EINVAL;
L
Linus Torvalds 已提交
787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811
	}

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;
812
	unsigned long user_addr;
K
Kirill Korotaev 已提交
813
	struct ipc_namespace *ns;
814 815 816
	struct shm_file_data *sfd;
	struct path path;
	mode_t f_mode;
L
Linus Torvalds 已提交
817

818 819
	err = -EINVAL;
	if (shmid < 0)
L
Linus Torvalds 已提交
820
		goto out;
821
	else if ((addr = (ulong)shmaddr)) {
L
Linus Torvalds 已提交
822 823 824 825 826 827 828
		if (addr & (SHMLBA-1)) {
			if (shmflg & SHM_RND)
				addr &= ~(SHMLBA-1);	   /* round down */
			else
#ifndef __ARCH_FORCE_SHMLBA
				if (addr & ~PAGE_MASK)
#endif
829
					goto out;
L
Linus Torvalds 已提交
830 831 832 833
		}
		flags = MAP_SHARED | MAP_FIXED;
	} else {
		if ((shmflg & SHM_REMAP))
834
			goto out;
L
Linus Torvalds 已提交
835 836 837 838 839 840 841

		flags = MAP_SHARED;
	}

	if (shmflg & SHM_RDONLY) {
		prot = PROT_READ;
		acc_mode = S_IRUGO;
842
		f_mode = FMODE_READ;
L
Linus Torvalds 已提交
843 844 845
	} else {
		prot = PROT_READ | PROT_WRITE;
		acc_mode = S_IRUGO | S_IWUGO;
846
		f_mode = FMODE_READ | FMODE_WRITE;
L
Linus Torvalds 已提交
847 848 849 850 851 852 853 854 855 856
	}
	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
857
	ns = current->nsproxy->ipc_ns;
858 859 860
	shp = shm_lock_check(ns, shmid);
	if (IS_ERR(shp)) {
		err = PTR_ERR(shp);
L
Linus Torvalds 已提交
861
		goto out;
862
	}
863 864 865 866

	err = -EACCES;
	if (ipcperms(&shp->shm_perm, acc_mode))
		goto out_unlock;
L
Linus Torvalds 已提交
867 868

	err = security_shm_shmat(shp, shmaddr, shmflg);
869 870 871 872
	if (err)
		goto out_unlock;

	path.dentry = dget(shp->shm_file->f_path.dentry);
873
	path.mnt    = shp->shm_file->f_path.mnt;
L
Linus Torvalds 已提交
874
	shp->shm_nattch++;
875
	size = i_size_read(path.dentry->d_inode);
L
Linus Torvalds 已提交
876 877
	shm_unlock(shp);

878 879 880
	err = -ENOMEM;
	sfd = kzalloc(sizeof(*sfd), GFP_KERNEL);
	if (!sfd)
881
		goto out_put_dentry;
882

883
	file = alloc_file(path.mnt, path.dentry, f_mode, &shm_file_operations);
884 885 886 887 888
	if (!file)
		goto out_free;

	file->private_data = sfd;
	file->f_mapping = shp->shm_file->f_mapping;
N
Nadia Derbey 已提交
889
	sfd->id = shp->shm_perm.id;
890 891 892 893
	sfd->ns = get_ipc_ns(ns);
	sfd->file = shp->shm_file;
	sfd->vm_ops = NULL;

L
Linus Torvalds 已提交
894 895
	down_write(&current->mm->mmap_sem);
	if (addr && !(shmflg & SHM_REMAP)) {
896
		err = -EINVAL;
L
Linus Torvalds 已提交
897 898 899 900 901 902 903 904 905 906 907
		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;
	}
		
908 909 910 911 912
	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
913 914 915
invalid:
	up_write(&current->mm->mmap_sem);

916 917 918
	fput(file);

out_nattch:
N
Nadia Derbey 已提交
919
	down_write(&shm_ids(ns).rw_mutex);
N
Nadia Derbey 已提交
920
	shp = shm_lock(ns, shmid);
921
	BUG_ON(IS_ERR(shp));
L
Linus Torvalds 已提交
922 923
	shp->shm_nattch--;
	if(shp->shm_nattch == 0 &&
A
Andrew Morton 已提交
924
	   shp->shm_perm.mode & SHM_DEST)
K
Kirill Korotaev 已提交
925
		shm_destroy(ns, shp);
L
Linus Torvalds 已提交
926 927
	else
		shm_unlock(shp);
N
Nadia Derbey 已提交
928
	up_write(&shm_ids(ns).rw_mutex);
L
Linus Torvalds 已提交
929 930 931

out:
	return err;
932 933 934 935 936 937 938

out_unlock:
	shm_unlock(shp);
	goto out;

out_free:
	kfree(sfd);
939
out_put_dentry:
940 941
	dput(path.dentry);
	goto out_nattch;
L
Linus Torvalds 已提交
942 943
}

S
Stephen Rothwell 已提交
944 945 946 947 948 949 950 951 952 953 954 955
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;
}

L
Linus Torvalds 已提交
956 957 958 959 960 961 962 963 964 965 966 967
/*
 * 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;

968 969 970
	if (addr & ~PAGE_MASK)
		return retval;

L
Linus Torvalds 已提交
971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002
	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.
		 */
1003
		if ((vma->vm_ops == &shm_vm_ops) &&
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Linus Torvalds 已提交
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			(vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {


J
Josef Sipek 已提交
1007
			size = vma->vm_file->f_path.dentry->d_inode->i_size;
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Linus Torvalds 已提交
1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026
			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.
	 */
1027
	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 */
1032
		if ((vma->vm_ops == &shm_vm_ops) &&
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Linus Torvalds 已提交
1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043
			(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
1044
static int sysvipc_shm_proc_show(struct seq_file *s, void *it)
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Linus Torvalds 已提交
1045
{
1046
	struct shmid_kernel *shp = it;
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1048 1049 1050 1051 1052
#if BITS_PER_LONG <= 32
#define SIZE_SPEC "%10lu"
#else
#define SIZE_SPEC "%21lu"
#endif
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1054 1055 1056
	return seq_printf(s,
			  "%10d %10d  %4o " SIZE_SPEC " %5u %5u  "
			  "%5lu %5u %5u %5u %5u %10lu %10lu %10lu\n",
1057
			  shp->shm_perm.key,
N
Nadia Derbey 已提交
1058
			  shp->shm_perm.id,
A
Andrew Morton 已提交
1059
			  shp->shm_perm.mode,
1060 1061 1062
			  shp->shm_segsz,
			  shp->shm_cprid,
			  shp->shm_lprid,
1063
			  shp->shm_nattch,
1064 1065 1066 1067 1068 1069 1070
			  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