embox

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/**
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 * @file
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 *
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 * @date 06.08.09
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 * @author Anton Bondarev
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 */
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#include <stddef.h>
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#include <assert.h>
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#include <errno.h>
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#include <util/err.h>
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#include <fs/inode.h>
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#include <fs/file_desc.h>
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#include <fs/kfile.h>
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struct idesc *kopen(struct inode *node, int flag) {
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	struct super_block *sb;
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	struct file_desc *desc;
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	const struct file_operations *ops;
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	int ret;
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	struct idesc *idesc;
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	assert(node);
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	assertf(!(flag & (O_CREAT | O_EXCL)), "use kcreat() instead kopen()");
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	assertf(!(flag & O_DIRECTORY), "use mkdir() instead kopen()");
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	sb = node->i_sb;
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	/* if we try open a file (not special) we must have the file system */
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	if (NULL == sb) {
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		SET_ERRNO(ENOSUPP);
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		return NULL;
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	}
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	if (S_ISDIR(node->i_mode)) {
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		ops = sb->sb_fops;
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	} else {
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		if (NULL == sb->sb_fops) {
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			SET_ERRNO(ENOSUPP);
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			return NULL;
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		}
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		ops = sb->sb_fops;
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		if (S_ISCHR(node->i_mode)) {
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			/* Note: we suppose this node belongs to devfs */
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			idesc = ops->open(node, NULL, flag);
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			idesc->idesc_flags = flag;
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			return idesc;
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		}
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	}
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	if(ops == NULL) {
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		SET_ERRNO(ENOSUPP);
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		return NULL;
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	}
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	desc = file_desc_create(node, flag);
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	if (0 != ptr2err(desc)) {
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		SET_ERRNO(-(uintptr_t)desc);
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		return NULL;
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	}
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	desc->f_ops = ops;
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	if (desc->f_ops->open != NULL) {
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		idesc = desc->f_ops->open(node, &desc->f_idesc, flag);
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		if (ptr2err(idesc)){
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			ret = (uintptr_t)idesc;
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			goto free_out;
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		}
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	} else {
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		idesc = &desc->f_idesc;
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	}
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	if ((struct idesc *)idesc == &desc->f_idesc) {
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		goto out;
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	} else {
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		file_desc_destroy(desc);
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		return idesc;
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	}
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free_out:
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	if (ret < 0) {
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		file_desc_destroy(desc);
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		SET_ERRNO(-ret);
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		return NULL;
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	}
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out:
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	return &desc->f_idesc;
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}
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