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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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 | /* * linux/fs/ncpfs/symlink.c * * Code for allowing symbolic links on NCPFS (i.e. NetWare) * Symbolic links are not supported on native NetWare, so we use an * infrequently-used flag (Sh) and store a two-word magic header in * the file to make sure we don't accidentally use a non-link file * as a link. * * from linux/fs/ext2/symlink.c * * Copyright (C) 1998-99, Frank A. Vorstenbosch * * ncpfs symlink handling code * NLS support (c) 1999 Petr Vandrovec * */ #include <linux/config.h> #ifdef CONFIG_NCPFS_EXTRAS #include <asm/uaccess.h> #include <asm/segment.h> #include <linux/errno.h> #include <linux/fs.h> #include <linux/ncp_fs.h> #include <linux/sched.h> #include <linux/mm.h> #include <linux/stat.h> #include "ncplib_kernel.h" /* these magic numbers must appear in the symlink file -- this makes it a bit more resilient against the magic attributes being set on random files. */ #define NCP_SYMLINK_MAGIC0 le32_to_cpu(0x6c6d7973) /* "symlnk->" */ #define NCP_SYMLINK_MAGIC1 le32_to_cpu(0x3e2d6b6e) static int ncp_readlink(struct dentry *, char *, int); static struct dentry *ncp_follow_link(struct dentry *, struct dentry *, unsigned int); int ncp_create_new(struct inode *dir, struct dentry *dentry, int mode,int attributes); /* * symlinks can't do much... */ struct inode_operations ncp_symlink_inode_operations={ NULL, /* no file-operations */ NULL, /* create */ NULL, /* lookup */ NULL, /* link */ NULL, /* unlink */ NULL, /* symlink */ NULL, /* mkdir */ NULL, /* rmdir */ NULL, /* mknod */ NULL, /* rename */ ncp_readlink, /* readlink */ ncp_follow_link, /* follow_link */ NULL, /* get_block */ NULL, /* readpage */ NULL, /* writepage */ NULL, /* flushpage */ NULL, /* truncate */ NULL, /* permission */ NULL, /* smap */ NULL /* revalidate */ }; /* ----- follow a symbolic link ------------------------------------------ */ static struct dentry *ncp_follow_link(struct dentry *dentry, struct dentry *base, unsigned int follow) { struct inode *inode=dentry->d_inode; int error, length, cnt; char *link; #ifdef DEBUG PRINTK("ncp_follow_link(dentry=%p,base=%p,follow=%u)\n",dentry,base,follow); #endif if(!S_ISLNK(inode->i_mode)) { dput(base); return ERR_PTR(-EINVAL); } if(ncp_make_open(inode,O_RDONLY)) { dput(base); return ERR_PTR(-EIO); } for (cnt = 0; (link=(char *)kmalloc(NCP_MAX_SYMLINK_SIZE+1, GFP_NFS))==NULL; cnt++) { if (cnt > 10) { dput(base); return ERR_PTR(-EAGAIN); /* -ENOMEM? */ } schedule(); } error=ncp_read_kernel(NCP_SERVER(inode),NCP_FINFO(inode)->file_handle, 0,NCP_MAX_SYMLINK_SIZE,link,&length); if (error!=0 || length<NCP_MIN_SYMLINK_SIZE || ((__u32 *)link)[0]!=NCP_SYMLINK_MAGIC0 || ((__u32 *)link)[1]!=NCP_SYMLINK_MAGIC1) { dput(base); kfree(link); return ERR_PTR(-EIO); } link[length]=0; vol2io(NCP_SERVER(inode), link+8, 0); /* UPDATE_ATIME(inode); */ base=lookup_dentry(link+8, base, follow); kfree(link); return base; } /* ----- read symbolic link ---------------------------------------------- */ static int ncp_readlink(struct dentry * dentry, char * buffer, int buflen) { struct inode *inode=dentry->d_inode; char *link; int length,error; #ifdef DEBUG PRINTK("ncp_readlink(dentry=%p,buffer=%p,buflen=%d)\n",dentry,buffer,buflen); #endif if(!S_ISLNK(inode->i_mode)) return -EINVAL; if(ncp_make_open(inode,O_RDONLY)) return -EIO; if((link=(char *)kmalloc(NCP_MAX_SYMLINK_SIZE+1,GFP_NFS))==NULL) return -ENOMEM; error = ncp_read_kernel(NCP_SERVER(inode),NCP_FINFO(inode)->file_handle, 0,NCP_MAX_SYMLINK_SIZE,link,&length); if (error!=0 || length < NCP_MIN_SYMLINK_SIZE || buflen < (length-8) || ((__u32 *)link)[0]!=NCP_SYMLINK_MAGIC0 ||((__u32 *)link)[1]!=NCP_SYMLINK_MAGIC1) { error = -EIO; goto out; } link[length] = 0; vol2io(NCP_SERVER(inode), link+8, 0); error = length - 8; if(copy_to_user(buffer, link+8, error)) error = -EFAULT; out:; kfree(link); return error; } /* ----- create a new symbolic link -------------------------------------- */ int ncp_symlink(struct inode *dir, struct dentry *dentry, const char *symname) { int i,length; struct inode *inode; char *link; #ifdef DEBUG PRINTK("ncp_symlink(dir=%p,dentry=%p,symname=%s)\n",dir,dentry,symname); #endif if (!(NCP_SERVER(dir)->m.flags & NCP_MOUNT_SYMLINKS)) return -EPERM; /* EPERM is returned by VFS if symlink procedure does not exist */ if ((length=strlen(symname))>NCP_MAX_SYMLINK_SIZE) return -EINVAL; if ((link=(char *)kmalloc(length+9,GFP_NFS))==NULL) return -ENOMEM; if (ncp_create_new(dir,dentry,0,aSHARED|aHIDDEN)) { kfree(link); return -EIO; } inode=dentry->d_inode; ((__u32 *)link)[0]=NCP_SYMLINK_MAGIC0; ((__u32 *)link)[1]=NCP_SYMLINK_MAGIC1; memcpy(link+8, symname, length+1); /* including last zero for io2vol */ /* map to/from server charset, do not touch upper/lower case as symlink can point out of ncp filesystem */ io2vol(NCP_SERVER(inode), link+8, 0); if(ncp_write_kernel(NCP_SERVER(inode), NCP_FINFO(inode)->file_handle, 0, length+8, link, &i) || i!=length+8) { kfree(link); return -EIO; } kfree(link); return 0; } #endif /* ----- EOF ----- */ |