Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 917 insertions, 0 deletions

diff --git a/ipc/shm.c b/ipc/shm.c
new file mode 100644
index 000000000000..06cd5c91056f
--- /dev/null
+++ b/ipc/shm.c
@@ -0,0 +1,917 @@
+/*
+ * 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>
+ *
+ */
+
+#include <linux/config.h>
+#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/proc_fs.h>
+#include <linux/shmem_fs.h>
+#include <linux/security.h>
+#include <linux/syscalls.h>
+#include <linux/audit.h>
+#include <asm/uaccess.h>
+
+#include "util.h"
+
+#define shm_flags	shm_perm.mode
+
+static struct file_operations shm_file_operations;
+static struct vm_operations_struct shm_vm_ops;
+
+static struct ipc_ids shm_ids;
+
+#define shm_lock(id)	((struct shmid_kernel*)ipc_lock(&shm_ids,id))
+#define shm_unlock(shp)	ipc_unlock(&(shp)->shm_perm)
+#define shm_get(id)	((struct shmid_kernel*)ipc_get(&shm_ids,id))
+#define shm_buildid(id, seq) \
+	ipc_buildid(&shm_ids, id, seq)
+
+static int newseg (key_t key, int shmflg, size_t size);
+static void shm_open (struct vm_area_struct *shmd);
+static void shm_close (struct vm_area_struct *shmd);
+#ifdef CONFIG_PROC_FS
+static int sysvipc_shm_read_proc(char *buffer, char **start, off_t offset, int length, int *eof, void *data);
+#endif
+
+size_t	shm_ctlmax = SHMMAX;
+size_t 	shm_ctlall = SHMALL;
+int 	shm_ctlmni = SHMMNI;
+
+static int shm_tot; /* total number of shared memory pages */
+
+void __init shm_init (void)
+{
+	ipc_init_ids(&shm_ids, 1);
+#ifdef CONFIG_PROC_FS
+	create_proc_read_entry("sysvipc/shm", 0, NULL, sysvipc_shm_read_proc, NULL);
+#endif
+}
+
+static inline int shm_checkid(struct shmid_kernel *s, int id)
+{
+	if (ipc_checkid(&shm_ids,&s->shm_perm,id))
+		return -EIDRM;
+	return 0;
+}
+
+static inline struct shmid_kernel *shm_rmid(int id)
+{
+	return (struct shmid_kernel *)ipc_rmid(&shm_ids,id);
+}
+
+static inline int shm_addid(struct shmid_kernel *shp)
+{
+	return ipc_addid(&shm_ids, &shp->shm_perm, shm_ctlmni);
+}
+
+
+
+static inline void shm_inc (int id) {
+	struct shmid_kernel *shp;
+
+	if(!(shp = shm_lock(id)))
+		BUG();
+	shp->shm_atim = get_seconds();
+	shp->shm_lprid = current->tgid;
+	shp->shm_nattch++;
+	shm_unlock(shp);
+}
+
+/* This is called by fork, once for every shm attach. */
+static void shm_open (struct vm_area_struct *shmd)
+{
+	shm_inc (shmd->vm_file->f_dentry->d_inode->i_ino);
+}
+
+/*
+ * shm_destroy - free the struct shmid_kernel
+ *
+ * @shp: struct to free
+ *
+ * It has to be called with shp and shm_ids.sem locked,
+ * but returns with shp unlocked and freed.
+ */
+static void shm_destroy (struct shmid_kernel *shp)
+{
+	shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
+	shm_rmid (shp->id);
+	shm_unlock(shp);
+	if (!is_file_hugepages(shp->shm_file))
+		shmem_lock(shp->shm_file, 0, shp->mlock_user);
+	else
+		user_shm_unlock(shp->shm_file->f_dentry->d_inode->i_size,
+						shp->mlock_user);
+	fput (shp->shm_file);
+	security_shm_free(shp);
+	ipc_rcu_putref(shp);
+}
+
+/*
+ * remove the attach descriptor shmd.
+ * 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.
+ */
+static void shm_close (struct vm_area_struct *shmd)
+{
+	struct file * file = shmd->vm_file;
+	int id = file->f_dentry->d_inode->i_ino;
+	struct shmid_kernel *shp;
+
+	down (&shm_ids.sem);
+	/* remove from the list of attaches of the shm segment */
+	if(!(shp = shm_lock(id)))
+		BUG();
+	shp->shm_lprid = current->tgid;
+	shp->shm_dtim = get_seconds();
+	shp->shm_nattch--;
+	if(shp->shm_nattch == 0 &&
+	   shp->shm_flags & SHM_DEST)
+		shm_destroy (shp);
+	else
+		shm_unlock(shp);
+	up (&shm_ids.sem);
+}
+
+static int shm_mmap(struct file * file, struct vm_area_struct * vma)
+{
+	file_accessed(file);
+	vma->vm_ops = &shm_vm_ops;
+	shm_inc(file->f_dentry->d_inode->i_ino);
+	return 0;
+}
+
+static struct file_operations shm_file_operations = {
+	.mmap	= shm_mmap
+};
+
+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 */
+	.nopage	= shmem_nopage,
+#ifdef CONFIG_NUMA
+	.set_policy = shmem_set_policy,
+	.get_policy = shmem_get_policy,
+#endif
+};
+
+static int newseg (key_t key, int shmflg, size_t size)
+{
+	int error;
+	struct shmid_kernel *shp;
+	int numpages = (size + PAGE_SIZE -1) >> PAGE_SHIFT;
+	struct file * file;
+	char name[13];
+	int id;
+
+	if (size < SHMMIN || size > shm_ctlmax)
+		return -EINVAL;
+
+	if (shm_tot + numpages >= shm_ctlall)
+		return -ENOSPC;
+
+	shp = ipc_rcu_alloc(sizeof(*shp));
+	if (!shp)
+		return -ENOMEM;
+
+	shp->shm_perm.key = key;
+	shp->shm_flags = (shmflg & S_IRWXUGO);
+	shp->mlock_user = NULL;
+
+	shp->shm_perm.security = NULL;
+	error = security_shm_alloc(shp);
+	if (error) {
+		ipc_rcu_putref(shp);
+		return error;
+	}
+
+	if (shmflg & SHM_HUGETLB) {
+		/* hugetlb_zero_setup takes care of mlock user accounting */
+		file = hugetlb_zero_setup(size);
+		shp->mlock_user = current->user;
+	} else {
+		sprintf (name, "SYSV%08x", key);
+		file = shmem_file_setup(name, size, VM_ACCOUNT);
+	}
+	error = PTR_ERR(file);
+	if (IS_ERR(file))
+		goto no_file;
+
+	error = -ENOSPC;
+	id = shm_addid(shp);
+	if(id == -1) 
+		goto no_id;
+
+	shp->shm_cprid = current->tgid;
+	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->id = shm_buildid(id,shp->shm_perm.seq);
+	shp->shm_file = file;
+	file->f_dentry->d_inode->i_ino = shp->id;
+	if (shmflg & SHM_HUGETLB)
+		set_file_hugepages(file);
+	else
+		file->f_op = &shm_file_operations;
+	shm_tot += numpages;
+	shm_unlock(shp);
+	return shp->id;
+
+no_id:
+	fput(file);
+no_file:
+	security_shm_free(shp);
+	ipc_rcu_putref(shp);
+	return error;
+}
+
+asmlinkage long sys_shmget (key_t key, size_t size, int shmflg)
+{
+	struct shmid_kernel *shp;
+	int err, id = 0;
+
+	down(&shm_ids.sem);
+	if (key == IPC_PRIVATE) {
+		err = newseg(key, shmflg, size);
+	} else if ((id = ipc_findkey(&shm_ids, key)) == -1) {
+		if (!(shmflg & IPC_CREAT))
+			err = -ENOENT;
+		else
+			err = newseg(key, shmflg, size);
+	} else if ((shmflg & IPC_CREAT) && (shmflg & IPC_EXCL)) {
+		err = -EEXIST;
+	} else {
+		shp = shm_lock(id);
+		if(shp==NULL)
+			BUG();
+		if (shp->shm_segsz < size)
+			err = -EINVAL;
+		else if (ipcperms(&shp->shm_perm, shmflg))
+			err = -EACCES;
+		else {
+			int shmid = shm_buildid(id, shp->shm_perm.seq);
+			err = security_shm_associate(shp, shmflg);
+			if (!err)
+				err = shmid;
+		}
+		shm_unlock(shp);
+	}
+	up(&shm_ids.sem);
+
+	return err;
+}
+
+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;
+		out->mode	= tbuf.shm_flags;
+
+		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;
+		out->mode	= tbuf_old.shm_flags;
+
+		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;
+	}
+}
+
+static void shm_get_stat(unsigned long *rss, unsigned long *swp) 
+{
+	int i;
+
+	*rss = 0;
+	*swp = 0;
+
+	for (i = 0; i <= shm_ids.max_id; i++) {
+		struct shmid_kernel *shp;
+		struct inode *inode;
+
+		shp = shm_get(i);
+		if(!shp)
+			continue;
+
+		inode = shp->shm_file->f_dentry->d_inode;
+
+		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);
+		}
+	}
+}
+
+asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf)
+{
+	struct shm_setbuf setbuf;
+	struct shmid_kernel *shp;
+	int err, version;
+
+	if (cmd < 0 || shmid < 0) {
+		err = -EINVAL;
+		goto out;
+	}
+
+	version = ipc_parse_version(&cmd);
+
+	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));
+		shminfo.shmmni = shminfo.shmseg = shm_ctlmni;
+		shminfo.shmmax = shm_ctlmax;
+		shminfo.shmall = shm_ctlall;
+
+		shminfo.shmmin = SHMMIN;
+		if(copy_shminfo_to_user (buf, &shminfo, version))
+			return -EFAULT;
+		/* reading a integer is always atomic */
+		err= shm_ids.max_id;
+		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));
+		down(&shm_ids.sem);
+		shm_info.used_ids = shm_ids.in_use;
+		shm_get_stat (&shm_info.shm_rss, &shm_info.shm_swp);
+		shm_info.shm_tot = shm_tot;
+		shm_info.swap_attempts = 0;
+		shm_info.swap_successes = 0;
+		err = shm_ids.max_id;
+		up(&shm_ids.sem);
+		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;
+		memset(&tbuf, 0, sizeof(tbuf));
+		shp = shm_lock(shmid);
+		if(shp==NULL) {
+			err = -EINVAL;
+			goto out;
+		} else if(cmd==SHM_STAT) {
+			err = -EINVAL;
+			if (shmid > shm_ids.max_id)
+				goto out_unlock;
+			result = shm_buildid(shmid, shp->shm_perm.seq);
+		} else {
+			err = shm_checkid(shp,shmid);
+			if(err)
+				goto out_unlock;
+			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;
+		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;
+		if (!is_file_hugepages(shp->shm_file))
+			tbuf.shm_nattch	= shp->shm_nattch;
+		else
+			tbuf.shm_nattch = file_count(shp->shm_file) - 1;
+		shm_unlock(shp);
+		if(copy_shmid_to_user (buf, &tbuf, version))
+			err = -EFAULT;
+		else
+			err = result;
+		goto out;
+	}
+	case SHM_LOCK:
+	case SHM_UNLOCK:
+	{
+		shp = shm_lock(shmid);
+		if(shp==NULL) {
+			err = -EINVAL;
+			goto out;
+		}
+		err = shm_checkid(shp,shmid);
+		if(err)
+			goto out_unlock;
+
+		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);
+				if (!err) {
+					shp->shm_flags |= SHM_LOCKED;
+					shp->mlock_user = user;
+				}
+			}
+		} else if (!is_file_hugepages(shp->shm_file)) {
+			shmem_lock(shp->shm_file, 0, shp->mlock_user);
+			shp->shm_flags &= ~SHM_LOCKED;
+			shp->mlock_user = NULL;
+		}
+		shm_unlock(shp);
+		goto out;
+	}
+	case IPC_RMID:
+	{
+		/*
+		 *	We cannot simply remove the file. The SVID states
+		 *	that the block remains until the last person
+		 *	detaches from it, then is deleted. A shmat() on
+		 *	an RMID segment is legal in older Linux and if 
+		 *	we change it apps break...
+		 *
+		 *	Instead we set a destroyed flag, and then blow
+		 *	the name away when the usage hits zero.
+		 */
+		down(&shm_ids.sem);
+		shp = shm_lock(shmid);
+		err = -EINVAL;
+		if (shp == NULL) 
+			goto out_up;
+		err = shm_checkid(shp, shmid);
+		if(err)
+			goto out_unlock_up;
+
+		if (current->euid != shp->shm_perm.uid &&
+		    current->euid != shp->shm_perm.cuid && 
+		    !capable(CAP_SYS_ADMIN)) {
+			err=-EPERM;
+			goto out_unlock_up;
+		}
+
+		err = security_shm_shmctl(shp, cmd);
+		if (err)
+			goto out_unlock_up;
+
+		if (shp->shm_nattch){
+			shp->shm_flags |= SHM_DEST;
+			/* Do not find it any more */
+			shp->shm_perm.key = IPC_PRIVATE;
+			shm_unlock(shp);
+		} else
+			shm_destroy (shp);
+		up(&shm_ids.sem);
+		goto out;
+	}
+
+	case IPC_SET:
+	{
+		if (copy_shmid_from_user (&setbuf, buf, version)) {
+			err = -EFAULT;
+			goto out;
+		}
+		if ((err = audit_ipc_perms(0, setbuf.uid, setbuf.gid, setbuf.mode)))
+			return err;
+		down(&shm_ids.sem);
+		shp = shm_lock(shmid);
+		err=-EINVAL;
+		if(shp==NULL)
+			goto out_up;
+		err = shm_checkid(shp,shmid);
+		if(err)
+			goto out_unlock_up;
+		err=-EPERM;
+		if (current->euid != shp->shm_perm.uid &&
+		    current->euid != shp->shm_perm.cuid && 
+		    !capable(CAP_SYS_ADMIN)) {
+			goto out_unlock_up;
+		}
+
+		err = security_shm_shmctl(shp, cmd);
+		if (err)
+			goto out_unlock_up;
+		
+		shp->shm_perm.uid = setbuf.uid;
+		shp->shm_perm.gid = setbuf.gid;
+		shp->shm_flags = (shp->shm_flags & ~S_IRWXUGO)
+			| (setbuf.mode & S_IRWXUGO);
+		shp->shm_ctim = get_seconds();
+		break;
+	}
+
+	default:
+		err = -EINVAL;
+		goto out;
+	}
+
+	err = 0;
+out_unlock_up:
+	shm_unlock(shp);
+out_up:
+	up(&shm_ids.sem);
+	goto out;
+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;
+	unsigned long o_flags;
+	int acc_mode;
+	void *user_addr;
+
+	if (shmid < 0) {
+		err = -EINVAL;
+		goto out;
+	} else if ((addr = (ulong)shmaddr)) {
+		if (addr & (SHMLBA-1)) {
+			if (shmflg & SHM_RND)
+				addr &= ~(SHMLBA-1);	   /* round down */
+			else
+#ifndef __ARCH_FORCE_SHMLBA
+				if (addr & ~PAGE_MASK)
+#endif
+					return -EINVAL;
+		}
+		flags = MAP_SHARED | MAP_FIXED;
+	} else {
+		if ((shmflg & SHM_REMAP))
+			return -EINVAL;
+
+		flags = MAP_SHARED;
+	}
+
+	if (shmflg & SHM_RDONLY) {
+		prot = PROT_READ;
+		o_flags = O_RDONLY;
+		acc_mode = S_IRUGO;
+	} else {
+		prot = PROT_READ | PROT_WRITE;
+		o_flags = O_RDWR;
+		acc_mode = S_IRUGO | S_IWUGO;
+	}
+	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...
+	 */
+	shp = shm_lock(shmid);
+	if(shp == NULL) {
+		err = -EINVAL;
+		goto out;
+	}
+	err = shm_checkid(shp,shmid);
+	if (err) {
+		shm_unlock(shp);
+		goto out;
+	}
+	if (ipcperms(&shp->shm_perm, acc_mode)) {
+		shm_unlock(shp);
+		err = -EACCES;
+		goto out;
+	}
+
+	err = security_shm_shmat(shp, shmaddr, shmflg);
+	if (err) {
+		shm_unlock(shp);
+		return err;
+	}
+		
+	file = shp->shm_file;
+	size = i_size_read(file->f_dentry->d_inode);
+	shp->shm_nattch++;
+	shm_unlock(shp);
+
+	down_write(&current->mm->mmap_sem);
+	if (addr && !(shmflg & SHM_REMAP)) {
+		user_addr = ERR_PTR(-EINVAL);
+		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;
+	}
+		
+	user_addr = (void*) do_mmap (file, addr, size, prot, flags, 0);
+
+invalid:
+	up_write(&current->mm->mmap_sem);
+
+	down (&shm_ids.sem);
+	if(!(shp = shm_lock(shmid)))
+		BUG();
+	shp->shm_nattch--;
+	if(shp->shm_nattch == 0 &&
+	   shp->shm_flags & SHM_DEST)
+		shm_destroy (shp);
+	else
+		shm_unlock(shp);
+	up (&shm_ids.sem);
+
+	*raddr = (unsigned long) user_addr;
+	err = 0;
+	if (IS_ERR(user_addr))
+		err = PTR_ERR(user_addr);
+out:
+	return err;
+}
+
+/*
+ * 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;
+
+	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.
+		 */
+		if ((vma->vm_ops == &shm_vm_ops || is_vm_hugetlb_page(vma)) &&
+			(vma->vm_start - addr)/PAGE_SIZE == vma->vm_pgoff) {
+
+
+			size = vma->vm_file->f_dentry->d_inode->i_size;
+			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.
+	 */
+	while (vma && (loff_t)(vma->vm_end - addr) <= size) {
+		next = vma->vm_next;
+
+		/* finding a matching vma now does not alter retval */
+		if ((vma->vm_ops == &shm_vm_ops || is_vm_hugetlb_page(vma)) &&
+			(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
+static int sysvipc_shm_read_proc(char *buffer, char **start, off_t offset, int length, int *eof, void *data)
+{
+	off_t pos = 0;
+	off_t begin = 0;
+	int i, len = 0;
+
+	down(&shm_ids.sem);
+	len += sprintf(buffer, "       key      shmid perms       size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime\n");
+
+	for(i = 0; i <= shm_ids.max_id; i++) {
+		struct shmid_kernel* shp;
+
+		shp = shm_lock(i);
+		if(shp!=NULL) {
+#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"
+			char *format;
+
+			if (sizeof(size_t) <= sizeof(int))
+				format = SMALL_STRING;
+			else
+				format = BIG_STRING;
+			len += sprintf(buffer + len, format,
+				shp->shm_perm.key,
+				shm_buildid(i, shp->shm_perm.seq),
+				shp->shm_flags,
+				shp->shm_segsz,
+				shp->shm_cprid,
+				shp->shm_lprid,
+				is_file_hugepages(shp->shm_file) ? (file_count(shp->shm_file) - 1) : shp->shm_nattch,
+				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);
+			shm_unlock(shp);
+
+			pos += len;
+			if(pos < offset) {
+				len = 0;
+				begin = pos;
+			}
+			if(pos > offset + length)
+				goto done;
+		}
+	}
+	*eof = 1;
+done:
+	up(&shm_ids.sem);
+	*start = buffer + (offset - begin);
+	len -= (offset - begin);
+	if(len > length)
+		len = length;
+	if(len < 0)
+		len = 0;
+	return len;
+}
+#endif