Eric Lee / smarc-fsl-linux-kernel

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ipc/msgutil.c 2.77 KB
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1da177e4c   Linus Torvalds   Linux-2.6.12-rc2 
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  /*
f30c22695   Uwe Zeisberger   fix file specific... 
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   * linux/ipc/msgutil.c
1da177e4c   Linus Torvalds   Linux-2.6.12-rc2 
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   * Copyright (C) 1999, 2004 Manfred Spraul
   *
   * This file is released under GNU General Public Licence version 2 or
   * (at your option) any later version.
   *
   * See the file COPYING for more details.
   */
  
  #include <linux/spinlock.h>
  #include <linux/init.h>
  #include <linux/security.h>
  #include <linux/slab.h>
  #include <linux/ipc.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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  DEFINE_SPINLOCK(mq_lock);
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  /*
   * The next 2 defines are here bc this is the only file
   * compiled when either CONFIG_SYSVIPC and CONFIG_POSIX_MQUEUE
   * and not CONFIG_IPC_NS.
   */
  struct ipc_namespace init_ipc_ns = {
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  	.count		= ATOMIC_INIT(1),
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  #ifdef CONFIG_POSIX_MQUEUE
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  	.mq_queues_max   = DFLT_QUEUESMAX,
  	.mq_msg_max      = DFLT_MSGMAX,
  	.mq_msgsize_max  = DFLT_MSGSIZEMAX,
  #endif
  };
  
  atomic_t nr_ipc_ns = ATOMIC_INIT(1);
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  struct msg_msgseg {
  	struct msg_msgseg* next;
  	/* the next part of the message follows immediately */
  };
  
  #define DATALEN_MSG	(PAGE_SIZE-sizeof(struct msg_msg))
  #define DATALEN_SEG	(PAGE_SIZE-sizeof(struct msg_msgseg))
  
  struct msg_msg *load_msg(const void __user *src, int len)
  {
  	struct msg_msg *msg;
  	struct msg_msgseg **pseg;
  	int err;
  	int alen;
  
  	alen = len;
  	if (alen > DATALEN_MSG)
  		alen = DATALEN_MSG;
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  	msg = kmalloc(sizeof(*msg) + alen, GFP_KERNEL);
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  	if (msg == NULL)
  		return ERR_PTR(-ENOMEM);
  
  	msg->next = NULL;
  	msg->security = NULL;
  
  	if (copy_from_user(msg + 1, src, alen)) {
  		err = -EFAULT;
  		goto out_err;
  	}
  
  	len -= alen;
  	src = ((char __user *)src) + alen;
  	pseg = &msg->next;
  	while (len > 0) {
  		struct msg_msgseg *seg;
  		alen = len;
  		if (alen > DATALEN_SEG)
  			alen = DATALEN_SEG;
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  		seg = kmalloc(sizeof(*seg) + alen,
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  						 GFP_KERNEL);
  		if (seg == NULL) {
  			err = -ENOMEM;
  			goto out_err;
  		}
  		*pseg = seg;
  		seg->next = NULL;
  		if (copy_from_user(seg + 1, src, alen)) {
  			err = -EFAULT;
  			goto out_err;
  		}
  		pseg = &seg->next;
  		len -= alen;
  		src = ((char __user *)src) + alen;
  	}
  
  	err = security_msg_msg_alloc(msg);
  	if (err)
  		goto out_err;
  
  	return msg;
  
  out_err:
  	free_msg(msg);
  	return ERR_PTR(err);
  }
  
  int store_msg(void __user *dest, struct msg_msg *msg, int len)
  {
  	int alen;
  	struct msg_msgseg *seg;
  
  	alen = len;
  	if (alen > DATALEN_MSG)
  		alen = DATALEN_MSG;
  	if (copy_to_user(dest, msg + 1, alen))
  		return -1;
  
  	len -= alen;
  	dest = ((char __user *)dest) + alen;
  	seg = msg->next;
  	while (len > 0) {
  		alen = len;
  		if (alen > DATALEN_SEG)
  			alen = DATALEN_SEG;
  		if (copy_to_user(dest, seg + 1, alen))
  			return -1;
  		len -= alen;
  		dest = ((char __user *)dest) + alen;
  		seg = seg->next;
  	}
  	return 0;
  }
  
  void free_msg(struct msg_msg *msg)
  {
  	struct msg_msgseg *seg;
  
  	security_msg_msg_free(msg);
  
  	seg = msg->next;
  	kfree(msg);
  	while (seg != NULL) {
  		struct msg_msgseg *tmp = seg->next;
  		kfree(seg);
  		seg = tmp;
  	}
  }