[PATCH 5/6] IPC namespace - shm

[Kirill Korotaev <dev@openvz.org>]

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IPC namespace support for IPC shm code.

Signed-Off-By: Pavel Emelianiov <xemul@openvz.org>
Signed-Off-By: Kirill Korotaev <dev@openvz.org>

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--- ./ipc/shm.c.ipcns	2006-06-06 14:47:58.000000000 +0400
+++ ./ipc/shm.c	2006-06-09 14:25:34.000000000 +0400
@@ -15,6 +15,10 @@
  *
  * support for audit of ipc object properties and permission changes
  * Dustin Kirkland <dustin.kirkland@us.ibm.com>
+ *
+ * namespaces support
+ * OpenVZ, SWsoft Inc.
+ * Pavel Emelianov <xemul@openvz.org>
  */
 
 #include <linux/config.h>
@@ -33,6 +37,7 @@
 #include <linux/ptrace.h>
 #include <linux/seq_file.h>
 #include <linux/mutex.h>
+#include <linux/nsproxy.h>
 
 #include <asm/uaccess.h>
 
@@ -41,59 +46,115 @@
 static struct file_operations shm_file_operations;
 static struct vm_operations_struct shm_vm_ops;
 
-static struct ipc_ids shm_ids;
+static struct ipc_ids init_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)
+#define shm_ids(ns)	(*((ns)->ids[IPC_SHM_IDS]))
 
-static int newseg (key_t key, int shmflg, size_t size);
+#define shm_lock(ns, id)		\
+	((struct shmid_kernel*)ipc_lock(&shm_ids(ns),id))
+#define shm_unlock(shp)			\
+	ipc_unlock(&(shp)->shm_perm)
+#define shm_get(ns, id)			\
+	((struct shmid_kernel*)ipc_get(&shm_ids(ns),id))
+#define shm_buildid(ns, id, seq)	\
+	ipc_buildid(&shm_ids(ns), id, seq)
+
+static int newseg (struct ipc_namespace *ns, 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);
+static void shm_destroy (struct ipc_namespace *ns, struct shmid_kernel *shp);
 #ifdef CONFIG_PROC_FS
 static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
 #endif
 
-size_t	shm_ctlmax = SHMMAX;
-size_t 	shm_ctlall = SHMALL;
-int 	shm_ctlmni = SHMMNI;
+static void __ipc_init __shm_init_ns(struct ipc_namespace *ns, struct ipc_ids *ids)
+{
+	ns->ids[IPC_SHM_IDS] = ids;
+	ns->shm_ctlmax = SHMMAX;
+	ns->shm_ctlall = SHMALL;
+	ns->shm_ctlmni = SHMMNI;
+	ns->shm_tot = 0;
+	ipc_init_ids(ids, 1);
+}
 
-static int shm_tot; /* total number of shared memory pages */
+static void do_shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *shp)
+{
+	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);
+}
+
+#ifdef CONFIG_IPC_NS
+int shm_init_ns(struct ipc_namespace *ns)
+{
+	struct ipc_ids *ids;
+
+	ids = kmalloc(sizeof(struct ipc_ids), GFP_KERNEL);
+	if (ids == NULL)
+		return -ENOMEM;
+
+	__shm_init_ns(ns, ids);
+	return 0;
+}
+
+void shm_exit_ns(struct ipc_namespace *ns)
+{
+	int i;
+	struct shmid_kernel *shp;
+
+	mutex_lock(&shm_ids(ns).mutex);
+	for (i = 0; i <= shm_ids(ns).max_id; i++) {
+		shp = shm_lock(ns, i);
+		if (shp == NULL)
+			continue;
+
+		do_shm_rmid(ns, shp);
+	}
+	mutex_unlock(&shm_ids(ns).mutex);
+
+	kfree(ns->ids[IPC_SHM_IDS]);
+	ns->ids[IPC_SHM_IDS] = NULL;
+}
+#endif
 
 void __init shm_init (void)
 {
-	ipc_init_ids(&shm_ids, 1);
+	__shm_init_ns(&init_ipc_ns, &init_shm_ids);
 	ipc_init_proc_interface("sysvipc/shm",
 				"       key      shmid perms       size  cpid  lpid nattch   uid   gid  cuid  cgid      atime      dtime      ctime\n",
-				&shm_ids,
-				sysvipc_shm_proc_show);
+				IPC_SHM_IDS, sysvipc_shm_proc_show);
 }
 
-static inline int shm_checkid(struct shmid_kernel *s, int id)
+static inline int shm_checkid(struct ipc_namespace *ns,
+		struct shmid_kernel *s, int id)
 {
-	if (ipc_checkid(&shm_ids,&s->shm_perm,id))
+	if (ipc_checkid(&shm_ids(ns), &s->shm_perm, id))
 		return -EIDRM;
 	return 0;
 }
 
-static inline struct shmid_kernel *shm_rmid(int id)
+static inline struct shmid_kernel *shm_rmid(struct ipc_namespace *ns, int id)
 {
-	return (struct shmid_kernel *)ipc_rmid(&shm_ids,id);
+	return (struct shmid_kernel *)ipc_rmid(&shm_ids(ns), id);
 }
 
-static inline int shm_addid(struct shmid_kernel *shp)
+static inline int shm_addid(struct ipc_namespace *ns, struct shmid_kernel *shp)
 {
-	return ipc_addid(&shm_ids, &shp->shm_perm, shm_ctlmni);
+	return ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni);
 }
 
 
 
-static inline void shm_inc (int id) {
+static inline void shm_inc(struct ipc_namespace *ns, int id)
+{
 	struct shmid_kernel *shp;
 
-	shp = shm_lock(id);
+	shp = shm_lock(ns, id);
 	BUG_ON(!shp);
 	shp->shm_atim = get_seconds();
 	shp->shm_lprid = current->tgid;
@@ -101,10 +162,13 @@ static inline void shm_inc (int id) {
 	shm_unlock(shp);
 }
 
+#define shm_file_ns(file) (*((struct ipc_namespace **)&(file)->private_data))
+
 /* This is called by fork, once for every shm attach. */
-static void shm_open (struct vm_area_struct *shmd)
+static void shm_open(struct vm_area_struct *shmd)
 {
-	shm_inc (shmd->vm_file->f_dentry->d_inode->i_ino);
+	shm_inc(shm_file_ns(shmd->vm_file),
+			shmd->vm_file->f_dentry->d_inode->i_ino);
 }
 
 /*
@@ -115,10 +179,10 @@ static void shm_open (struct vm_area_str
  * It has to be called with shp and shm_ids.mutex locked,
  * but returns with shp unlocked and freed.
  */
-static void shm_destroy (struct shmid_kernel *shp)
+static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp)
 {
-	shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
-	shm_rmid (shp->id);
+	ns->shm_tot -= (shp->shm_segsz + PAGE_SIZE - 1) >> PAGE_SHIFT;
+	shm_rmid(ns, shp->id);
 	shm_unlock(shp);
 	if (!is_file_hugepages(shp->shm_file))
 		shmem_lock(shp->shm_file, 0, shp->mlock_user);
@@ -141,20 +205,23 @@ static void shm_close (struct vm_area_st
 	struct file * file = shmd->vm_file;
 	int id = file->f_dentry->d_inode->i_ino;
 	struct shmid_kernel *shp;
+	struct ipc_namespace *ns;
 
-	mutex_lock(&shm_ids.mutex);
+	ns = shm_file_ns(file);
+
+	mutex_lock(&shm_ids(ns).mutex);
 	/* remove from the list of attaches of the shm segment */
-	shp = shm_lock(id);
+	shp = shm_lock(ns, id);
 	BUG_ON(!shp);
 	shp->shm_lprid = current->tgid;
 	shp->shm_dtim = get_seconds();
 	shp->shm_nattch--;
 	if(shp->shm_nattch == 0 &&
 	   shp->shm_perm.mode & SHM_DEST)
-		shm_destroy (shp);
+		shm_destroy(ns, shp);
 	else
 		shm_unlock(shp);
-	mutex_unlock(&shm_ids.mutex);
+	mutex_unlock(&shm_ids(ns).mutex);
 }
 
 static int shm_mmap(struct file * file, struct vm_area_struct * vma)
@@ -166,14 +233,25 @@ static int shm_mmap(struct file * file, 
 		vma->vm_ops = &shm_vm_ops;
 		if (!(vma->vm_flags & VM_WRITE))
 			vma->vm_flags &= ~VM_MAYWRITE;
-		shm_inc(file->f_dentry->d_inode->i_ino);
+		shm_inc(shm_file_ns(file), file->f_dentry->d_inode->i_ino);
 	}
 
 	return ret;
 }
 
+static int shm_release(struct inode *ino, struct file *file)
+{
+	struct ipc_namespace *ns;
+
+	ns = shm_file_ns(file);
+	put_ipc_ns(ns);
+	shm_file_ns(file) = NULL;
+	return 0;
+}
+
 static struct file_operations shm_file_operations = {
-	.mmap	= shm_mmap,
+	.mmap		= shm_mmap,
+	.release	= shm_release,
 #ifndef CONFIG_MMU
 	.get_unmapped_area = shmem_get_unmapped_area,
 #endif
@@ -189,7 +267,7 @@ static struct vm_operations_struct shm_v
 #endif
 };
 
-static int newseg (key_t key, int shmflg, size_t size)
+static int newseg (struct ipc_namespace *ns, key_t key, int shmflg, size_t size)
 {
 	int error;
 	struct shmid_kernel *shp;
@@ -198,10 +276,10 @@ static int newseg (key_t key, int shmflg
 	char name[13];
 	int id;
 
-	if (size < SHMMIN || size > shm_ctlmax)
+	if (size < SHMMIN || size > ns->shm_ctlmax)
 		return -EINVAL;
 
-	if (shm_tot + numpages >= shm_ctlall)
+	if (ns->shm_tot + numpages >= ns->shm_ctlall)
 		return -ENOSPC;
 
 	shp = ipc_rcu_alloc(sizeof(*shp));
@@ -240,7 +318,7 @@ static int newseg (key_t key, int shmflg
 		goto no_file;
 
 	error = -ENOSPC;
-	id = shm_addid(shp);
+	id = shm_addid(ns, shp);
 	if(id == -1) 
 		goto no_id;
 
@@ -250,15 +328,17 @@ static int newseg (key_t key, int shmflg
 	shp->shm_ctim = get_seconds();
 	shp->shm_segsz = size;
 	shp->shm_nattch = 0;
-	shp->id = shm_buildid(id,shp->shm_perm.seq);
+	shp->id = shm_buildid(ns, id, shp->shm_perm.seq);
 	shp->shm_file = file;
 	file->f_dentry->d_inode->i_ino = shp->id;
 
+	shm_file_ns(file) = get_ipc_ns(ns);
+
 	/* Hugetlb ops would have already been assigned. */
 	if (!(shmflg & SHM_HUGETLB))
 		file->f_op = &shm_file_operations;
 
-	shm_tot += numpages;
+	ns->shm_tot += numpages;
 	shm_unlock(shp);
 	return shp->id;
 
@@ -274,33 +354,36 @@ asmlinkage long sys_shmget (key_t key, s
 {
 	struct shmid_kernel *shp;
 	int err, id = 0;
+	struct ipc_namespace *ns;
 
-	mutex_lock(&shm_ids.mutex);
+	ns = current->nsproxy->ipc_ns;
+
+	mutex_lock(&shm_ids(ns).mutex);
 	if (key == IPC_PRIVATE) {
-		err = newseg(key, shmflg, size);
-	} else if ((id = ipc_findkey(&shm_ids, key)) == -1) {
+		err = newseg(ns, key, shmflg, size);
+	} else if ((id = ipc_findkey(&shm_ids(ns), key)) == -1) {
 		if (!(shmflg & IPC_CREAT))
 			err = -ENOENT;
 		else
-			err = newseg(key, shmflg, size);
+			err = newseg(ns, key, shmflg, size);
 	} else if ((shmflg & IPC_CREAT) && (shmflg & IPC_EXCL)) {
 		err = -EEXIST;
 	} else {
-		shp = shm_lock(id);
+		shp = shm_lock(ns, id);
 		BUG_ON(shp==NULL);
 		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);
+			int shmid = shm_buildid(ns, id, shp->shm_perm.seq);
 			err = security_shm_associate(shp, shmflg);
 			if (!err)
 				err = shmid;
 		}
 		shm_unlock(shp);
 	}
-	mutex_unlock(&shm_ids.mutex);
+	mutex_unlock(&shm_ids(ns).mutex);
 
 	return err;
 }
@@ -396,18 +479,19 @@ static inline unsigned long copy_shminfo
 	}
 }
 
-static void shm_get_stat(unsigned long *rss, unsigned long *swp) 
+static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss,
+		unsigned long *swp) 
 {
 	int i;
 
 	*rss = 0;
 	*swp = 0;
 
-	for (i = 0; i <= shm_ids.max_id; i++) {
+	for (i = 0; i <= shm_ids(ns).max_id; i++) {
 		struct shmid_kernel *shp;
 		struct inode *inode;
 
-		shp = shm_get(i);
+		shp = shm_get(ns, i);
 		if(!shp)
 			continue;
 
@@ -431,6 +515,7 @@ asmlinkage long sys_shmctl (int shmid, i
 	struct shm_setbuf setbuf;
 	struct shmid_kernel *shp;
 	int err, version;
+	struct ipc_namespace *ns;
 
 	if (cmd < 0 || shmid < 0) {
 		err = -EINVAL;
@@ -438,6 +523,7 @@ asmlinkage long sys_shmctl (int shmid, i
 	}
 
 	version = ipc_parse_version(&cmd);
+	ns = current->nsproxy->ipc_ns;
 
 	switch (cmd) { /* replace with proc interface ? */
 	case IPC_INFO:
@@ -449,15 +535,15 @@ asmlinkage long sys_shmctl (int shmid, i
 			return err;
 
 		memset(&shminfo,0,sizeof(shminfo));
-		shminfo.shmmni = shminfo.shmseg = shm_ctlmni;
-		shminfo.shmmax = shm_ctlmax;
-		shminfo.shmall = shm_ctlall;
+		shminfo.shmmni = shminfo.shmseg = ns->shm_ctlmni;
+		shminfo.shmmax = ns->shm_ctlmax;
+		shminfo.shmall = ns->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;
+		err= shm_ids(ns).max_id;
 		if(err<0)
 			err = 0;
 		goto out;
@@ -471,14 +557,14 @@ asmlinkage long sys_shmctl (int shmid, i
 			return err;
 
 		memset(&shm_info,0,sizeof(shm_info));
-		mutex_lock(&shm_ids.mutex);
-		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;
+		mutex_lock(&shm_ids(ns).mutex);
+		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;
 		shm_info.swap_attempts = 0;
 		shm_info.swap_successes = 0;
-		err = shm_ids.max_id;
-		mutex_unlock(&shm_ids.mutex);
+		err = shm_ids(ns).max_id;
+		mutex_unlock(&shm_ids(ns).mutex);
 		if(copy_to_user (buf, &shm_info, sizeof(shm_info))) {
 			err = -EFAULT;
 			goto out;
@@ -493,17 +579,17 @@ asmlinkage long sys_shmctl (int shmid, i
 		struct shmid64_ds tbuf;
 		int result;
 		memset(&tbuf, 0, sizeof(tbuf));
-		shp = shm_lock(shmid);
+		shp = shm_lock(ns, shmid);
 		if(shp==NULL) {
 			err = -EINVAL;
 			goto out;
 		} else if(cmd==SHM_STAT) {
 			err = -EINVAL;
-			if (shmid > shm_ids.max_id)
+			if (shmid > shm_ids(ns).max_id)
 				goto out_unlock;
-			result = shm_buildid(shmid, shp->shm_perm.seq);
+			result = shm_buildid(ns, shmid, shp->shm_perm.seq);
 		} else {
-			err = shm_checkid(shp,shmid);
+			err = shm_checkid(ns, shp,shmid);
 			if(err)
 				goto out_unlock;
 			result = 0;
@@ -535,12 +621,12 @@ asmlinkage long sys_shmctl (int shmid, i
 	case SHM_LOCK:
 	case SHM_UNLOCK:
 	{
-		shp = shm_lock(shmid);
+		shp = shm_lock(ns, shmid);
 		if(shp==NULL) {
 			err = -EINVAL;
 			goto out;
 		}
-		err = shm_checkid(shp,shmid);
+		err = shm_checkid(ns, shp,shmid);
 		if(err)
 			goto out_unlock;
 
@@ -591,12 +677,12 @@ asmlinkage long sys_shmctl (int shmid, i
 		 *	Instead we set a destroyed flag, and then blow
 		 *	the name away when the usage hits zero.
 		 */
-		mutex_lock(&shm_ids.mutex);
-		shp = shm_lock(shmid);
+		mutex_lock(&shm_ids(ns).mutex);
+		shp = shm_lock(ns, shmid);
 		err = -EINVAL;
 		if (shp == NULL) 
 			goto out_up;
-		err = shm_checkid(shp, shmid);
+		err = shm_checkid(ns, shp, shmid);
 		if(err)
 			goto out_unlock_up;
 
@@ -615,14 +701,8 @@ asmlinkage long sys_shmctl (int shmid, i
 		if (err)
 			goto out_unlock_up;
 
-		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 (shp);
-		mutex_unlock(&shm_ids.mutex);
+		do_shm_rmid(ns, shp);
+		mutex_unlock(&shm_ids(ns).mutex);
 		goto out;
 	}
 
@@ -632,12 +712,12 @@ asmlinkage long sys_shmctl (int shmid, i
 			err = -EFAULT;
 			goto out;
 		}
-		mutex_lock(&shm_ids.mutex);
-		shp = shm_lock(shmid);
+		mutex_lock(&shm_ids(ns).mutex);
+		shp = shm_lock(ns, shmid);
 		err=-EINVAL;
 		if(shp==NULL)
 			goto out_up;
-		err = shm_checkid(shp,shmid);
+		err = shm_checkid(ns, shp,shmid);
 		if(err)
 			goto out_unlock_up;
 		err = audit_ipc_obj(&(shp->shm_perm));
@@ -674,7 +754,7 @@ asmlinkage long sys_shmctl (int shmid, i
 out_unlock_up:
 	shm_unlock(shp);
 out_up:
-	mutex_unlock(&shm_ids.mutex);
+	mutex_unlock(&shm_ids(ns).mutex);
 	goto out;
 out_unlock:
 	shm_unlock(shp);
@@ -700,6 +780,7 @@ long do_shmat(int shmid, char __user *sh
 	unsigned long prot;
 	int acc_mode;
 	void *user_addr;
+	struct ipc_namespace *ns;
 
 	if (shmid < 0) {
 		err = -EINVAL;
@@ -738,12 +819,13 @@ long do_shmat(int shmid, char __user *sh
 	 * We cannot rely on the fs check since SYSV IPC does have an
 	 * additional creator id...
 	 */
-	shp = shm_lock(shmid);
+	ns = current->nsproxy->ipc_ns;
+	shp = shm_lock(ns, shmid);
 	if(shp == NULL) {
 		err = -EINVAL;
 		goto out;
 	}
-	err = shm_checkid(shp,shmid);
+	err = shm_checkid(ns, shp,shmid);
 	if (err) {
 		shm_unlock(shp);
 		goto out;
@@ -784,16 +866,16 @@ long do_shmat(int shmid, char __user *sh
 invalid:
 	up_write(&current->mm->mmap_sem);
 
-	mutex_lock(&shm_ids.mutex);
-	shp = shm_lock(shmid);
+	mutex_lock(&shm_ids(ns).mutex);
+	shp = shm_lock(ns, shmid);
 	BUG_ON(!shp);
 	shp->shm_nattch--;
 	if(shp->shm_nattch == 0 &&
 	   shp->shm_perm.mode & SHM_DEST)
-		shm_destroy (shp);
+		shm_destroy(ns, shp);
 	else
 		shm_unlock(shp);
-	mutex_unlock(&shm_ids.mutex);
+	mutex_unlock(&shm_ids(ns).mutex);
 
 	*raddr = (unsigned long) user_addr;
 	err = 0;