diff options
Diffstat (limited to 'fs/readdir.c')
| -rw-r--r-- | fs/readdir.c | 300 |
1 files changed, 300 insertions, 0 deletions
diff --git a/fs/readdir.c b/fs/readdir.c new file mode 100644 index 0000000..b03579b --- /dev/null +++ b/fs/readdir.c @@ -0,0 +1,300 @@ +/* + * linux/fs/readdir.c + * + * Copyright (C) 1995 Linus Torvalds + */ + +#include <linux/module.h> +#include <linux/time.h> +#include <linux/mm.h> +#include <linux/errno.h> +#include <linux/stat.h> +#include <linux/file.h> +#include <linux/smp_lock.h> +#include <linux/fs.h> +#include <linux/dirent.h> +#include <linux/security.h> +#include <linux/syscalls.h> +#include <linux/unistd.h> + +#include <asm/uaccess.h> + +int vfs_readdir(struct file *file, filldir_t filler, void *buf) +{ + struct inode *inode = file->f_dentry->d_inode; + int res = -ENOTDIR; + if (!file->f_op || !file->f_op->readdir) + goto out; + + res = security_file_permission(file, MAY_READ); + if (res) + goto out; + + down(&inode->i_sem); + res = -ENOENT; + if (!IS_DEADDIR(inode)) { + res = file->f_op->readdir(file, buf, filler); + file_accessed(file); + } + up(&inode->i_sem); +out: + return res; +} + +EXPORT_SYMBOL(vfs_readdir); + +/* + * Traditional linux readdir() handling.. + * + * "count=1" is a special case, meaning that the buffer is one + * dirent-structure in size and that the code can't handle more + * anyway. Thus the special "fillonedir()" function for that + * case (the low-level handlers don't need to care about this). + */ +#define NAME_OFFSET(de) ((int) ((de)->d_name - (char __user *) (de))) +#define ROUND_UP(x) (((x)+sizeof(long)-1) & ~(sizeof(long)-1)) + +#ifdef __ARCH_WANT_OLD_READDIR + +struct old_linux_dirent { + unsigned long d_ino; + unsigned long d_offset; + unsigned short d_namlen; + char d_name[1]; +}; + +struct readdir_callback { + struct old_linux_dirent __user * dirent; + int result; +}; + +static int fillonedir(void * __buf, const char * name, int namlen, loff_t offset, + ino_t ino, unsigned int d_type) +{ + struct readdir_callback * buf = (struct readdir_callback *) __buf; + struct old_linux_dirent __user * dirent; + + if (buf->result) + return -EINVAL; + buf->result++; + dirent = buf->dirent; + if (!access_ok(VERIFY_WRITE, dirent, + (unsigned long)(dirent->d_name + namlen + 1) - + (unsigned long)dirent)) + goto efault; + if ( __put_user(ino, &dirent->d_ino) || + __put_user(offset, &dirent->d_offset) || + __put_user(namlen, &dirent->d_namlen) || + __copy_to_user(dirent->d_name, name, namlen) || + __put_user(0, dirent->d_name + namlen)) + goto efault; + return 0; +efault: + buf->result = -EFAULT; + return -EFAULT; +} + +asmlinkage long old_readdir(unsigned int fd, struct old_linux_dirent __user * dirent, unsigned int count) +{ + int error; + struct file * file; + struct readdir_callback buf; + + error = -EBADF; + file = fget(fd); + if (!file) + goto out; + + buf.result = 0; + buf.dirent = dirent; + + error = vfs_readdir(file, fillonedir, &buf); + if (error >= 0) + error = buf.result; + + fput(file); +out: + return error; +} + +#endif /* __ARCH_WANT_OLD_READDIR */ + +/* + * New, all-improved, singing, dancing, iBCS2-compliant getdents() + * interface. + */ +struct linux_dirent { + unsigned long d_ino; + unsigned long d_off; + unsigned short d_reclen; + char d_name[1]; +}; + +struct getdents_callback { + struct linux_dirent __user * current_dir; + struct linux_dirent __user * previous; + int count; + int error; +}; + +static int filldir(void * __buf, const char * name, int namlen, loff_t offset, + ino_t ino, unsigned int d_type) +{ + struct linux_dirent __user * dirent; + struct getdents_callback * buf = (struct getdents_callback *) __buf; + int reclen = ROUND_UP(NAME_OFFSET(dirent) + namlen + 2); + + buf->error = -EINVAL; /* only used if we fail.. */ + if (reclen > buf->count) + return -EINVAL; + dirent = buf->previous; + if (dirent) { + if (__put_user(offset, &dirent->d_off)) + goto efault; + } + dirent = buf->current_dir; + if (__put_user(ino, &dirent->d_ino)) + goto efault; + if (__put_user(reclen, &dirent->d_reclen)) + goto efault; + if (copy_to_user(dirent->d_name, name, namlen)) + goto efault; + if (__put_user(0, dirent->d_name + namlen)) + goto efault; + if (__put_user(d_type, (char __user *) dirent + reclen - 1)) + goto efault; + buf->previous = dirent; + dirent = (void __user *)dirent + reclen; + buf->current_dir = dirent; + buf->count -= reclen; + return 0; +efault: + buf->error = -EFAULT; + return -EFAULT; +} + +asmlinkage long sys_getdents(unsigned int fd, struct linux_dirent __user * dirent, unsigned int count) +{ + struct file * file; + struct linux_dirent __user * lastdirent; + struct getdents_callback buf; + int error; + + error = -EFAULT; + if (!access_ok(VERIFY_WRITE, dirent, count)) + goto out; + + error = -EBADF; + file = fget(fd); + if (!file) + goto out; + + buf.current_dir = dirent; + buf.previous = NULL; + buf.count = count; + buf.error = 0; + + error = vfs_readdir(file, filldir, &buf); + if (error < 0) + goto out_putf; + error = buf.error; + lastdirent = buf.previous; + if (lastdirent) { + if (put_user(file->f_pos, &lastdirent->d_off)) + error = -EFAULT; + else + error = count - buf.count; + } + +out_putf: + fput(file); +out: + return error; +} + +#define ROUND_UP64(x) (((x)+sizeof(u64)-1) & ~(sizeof(u64)-1)) + +struct getdents_callback64 { + struct linux_dirent64 __user * current_dir; + struct linux_dirent64 __user * previous; + int count; + int error; +}; + +static int filldir64(void * __buf, const char * name, int namlen, loff_t offset, + ino_t ino, unsigned int d_type) +{ + struct linux_dirent64 __user *dirent; + struct getdents_callback64 * buf = (struct getdents_callback64 *) __buf; + int reclen = ROUND_UP64(NAME_OFFSET(dirent) + namlen + 1); + + buf->error = -EINVAL; /* only used if we fail.. */ + if (reclen > buf->count) + return -EINVAL; + dirent = buf->previous; + if (dirent) { + if (__put_user(offset, &dirent->d_off)) + goto efault; + } + dirent = buf->current_dir; + if (__put_user(ino, &dirent->d_ino)) + goto efault; + if (__put_user(0, &dirent->d_off)) + goto efault; + if (__put_user(reclen, &dirent->d_reclen)) + goto efault; + if (__put_user(d_type, &dirent->d_type)) + goto efault; + if (copy_to_user(dirent->d_name, name, namlen)) + goto efault; + if (__put_user(0, dirent->d_name + namlen)) + goto efault; + buf->previous = dirent; + dirent = (void __user *)dirent + reclen; + buf->current_dir = dirent; + buf->count -= reclen; + return 0; +efault: + buf->error = -EFAULT; + return -EFAULT; +} + +asmlinkage long sys_getdents64(unsigned int fd, struct linux_dirent64 __user * dirent, unsigned int count) +{ + struct file * file; + struct linux_dirent64 __user * lastdirent; + struct getdents_callback64 buf; + int error; + + error = -EFAULT; + if (!access_ok(VERIFY_WRITE, dirent, count)) + goto out; + + error = -EBADF; + file = fget(fd); + if (!file) + goto out; + + buf.current_dir = dirent; + buf.previous = NULL; + buf.count = count; + buf.error = 0; + + error = vfs_readdir(file, filldir64, &buf); + if (error < 0) + goto out_putf; + error = buf.error; + lastdirent = buf.previous; + if (lastdirent) { + typeof(lastdirent->d_off) d_off = file->f_pos; + error = -EFAULT; + if (__put_user(d_off, &lastdirent->d_off)) + goto out_putf; + error = count - buf.count; + } + +out_putf: + fput(file); +out: + return error; +} |
