/* * linux/fs/ext/symlink.c * * (C) 1992 Remy Card (card@masi.ibp.fr) * * from * * linux/fs/minix/symlink.c * * (C) 1991 Linus Torvalds * * ext symlink handling code */ #include <errno.h> #include <asm/segment.h> #include <linux/sched.h> #include <linux/fs.h> #include <linux/ext_fs.h> #include <linux/stat.h> static int ext_readlink(struct inode *, char *, int); static struct inode * ext_follow_link(struct inode *, struct inode *); /* * symlinks can't do much... */ struct inode_operations ext_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 */ ext_readlink, /* readlink */ ext_follow_link, /* follow_link */ NULL, /* bmap */ NULL /* truncate */ }; static struct inode * ext_follow_link(struct inode * dir, struct inode * inode) { unsigned short fs; struct buffer_head * bh; if (!dir) { dir = current->root; dir->i_count++; } if (!inode) { iput(dir); return NULL; } if (!S_ISLNK(inode->i_mode)) { iput(dir); return inode; } __asm__("mov %%fs,%0":"=r" (fs)); if ((current->link_count > 5) || !inode->i_data[0] || !(bh = bread(inode->i_dev, inode->i_data[0]))) { iput(dir); iput(inode); return NULL; } iput(inode); __asm__("mov %0,%%fs"::"r" ((unsigned short) 0x10)); current->link_count++; inode = _namei(bh->b_data,dir,1); current->link_count--; __asm__("mov %0,%%fs"::"r" (fs)); brelse(bh); return inode; } static int ext_readlink(struct inode * inode, char * buffer, int buflen) { struct buffer_head * bh; int i; char c; if (!S_ISLNK(inode->i_mode)) { iput(inode); return -EINVAL; } if (buflen > 1023) buflen = 1023; if (inode->i_data[0]) bh = bread(inode->i_dev, inode->i_data[0]); else bh = NULL; iput(inode); if (!bh) return 0; i = 0; while (i<buflen && (c = bh->b_data[i])) { i++; put_fs_byte(c,buffer++); } brelse(bh); return i; }