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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 | /* * symlink.c * * Copyright (c) 1999 Al Smith * * Portions derived from work (c) 1995,1996 Christian Vogelgsang. */ #include <linux/string.h> #include <linux/malloc.h> #include <linux/efs_fs.h> static int efs_readlink(struct dentry *, char *, int); static struct dentry * efs_follow_link(struct dentry *, struct dentry *, unsigned int); struct inode_operations efs_symlink_inode_operations = { NULL, /* no symlink file-operations */ NULL, /* create */ NULL, /* lookup */ NULL, /* link */ NULL, /* unlink */ NULL, /* symlink */ NULL, /* mkdir */ NULL, /* rmdir */ NULL, /* mknod */ NULL, /* rename */ efs_readlink, /* readlink */ efs_follow_link, /* follow_link */ NULL, /* get_block */ NULL, /* readpage */ NULL, /* writepage */ NULL, /* flushpage */ NULL, /* truncate */ NULL, /* permission */ NULL, /* smap */ NULL /* revalidate */ }; static char *efs_linktarget(struct inode *in, int *len) { char *name; struct buffer_head * bh; efs_block_t size = in->i_size; if (size > 2 * EFS_BLOCKSIZE) { printk(KERN_ERR "EFS: linktarget(): name too long: %lu\n", in->i_size); return NULL; } if (!(name = kmalloc(size + 1, GFP_KERNEL))) return NULL; /* read first 512 bytes of link target */ bh = bread(in->i_dev, efs_bmap(in, 0), EFS_BLOCKSIZE); if (!bh) { kfree(name); printk(KERN_ERR "EFS: linktarget(): couldn't read block %d\n", efs_bmap(in, 0)); return NULL; } memcpy(name, bh->b_data, (size > EFS_BLOCKSIZE) ? EFS_BLOCKSIZE : size); brelse(bh); if (size > EFS_BLOCKSIZE) { bh = bread(in->i_dev, efs_bmap(in, 1), EFS_BLOCKSIZE); if (!bh) { kfree(name); printk(KERN_ERR "EFS: linktarget(): couldn't read block %d\n", efs_bmap(in, 1)); return NULL; } memcpy(name + EFS_BLOCKSIZE, bh->b_data, size - EFS_BLOCKSIZE); brelse(bh); } name[size] = (char) 0; if (len) *len = size; return name; } static struct dentry *efs_follow_link(struct dentry *dentry, struct dentry *base, unsigned int follow) { char *name; struct inode *inode = dentry->d_inode; if (!(name = efs_linktarget(inode, NULL))) { dput(base); return ERR_PTR(-ELOOP); } base = lookup_dentry(name, base, follow); kfree(name); return base; } static int efs_readlink(struct dentry * dir, char * buf, int bufsiz) { int rc; char *name; struct inode *inode = dir->d_inode; if (!(name = efs_linktarget(inode, &bufsiz))) return 0; rc = copy_to_user(buf, name, bufsiz) ? -EFAULT : bufsiz; kfree(name); return rc; } |