/* * linux/fs/readdir.c * * Copyright (C) 1995 Linus Torvalds */ #include <linux/stddef.h> #include <linux/kernel.h> #include <linux/export.h> #include <linux/time.h> #include <linux/mm.h> #include <linux/errno.h> #include <linux/stat.h> #include <linux/file.h> #include <linux/fs.h> #include <linux/fsnotify.h> #include <linux/dirent.h> #include <linux/security.h> #include <linux/syscalls.h> #include <linux/unistd.h> #include <asm/uaccess.h> int iterate_dir(struct file *file, struct dir_context *ctx) { struct inode *inode = file_inode(file); int res = -ENOTDIR; if (!file->f_op->iterate) goto out; res = security_file_permission(file, MAY_READ); if (res) goto out; res = mutex_lock_killable(&inode->i_mutex); if (res) goto out; res = -ENOENT; if (!IS_DEADDIR(inode)) { ctx->pos = file->f_pos; res = file->f_op->iterate(file, ctx); file->f_pos = ctx->pos; fsnotify_access(file); file_accessed(file); } inode_unlock(inode); out: return res; } EXPORT_SYMBOL(iterate_dir); /* * 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). */ #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 dir_context ctx; struct old_linux_dirent __user * dirent; int result; }; static int fillonedir(struct dir_context *ctx, const char *name, int namlen, loff_t offset, u64 ino, unsigned int d_type) { struct readdir_callback *buf = container_of(ctx, struct readdir_callback, ctx); struct old_linux_dirent __user * dirent; unsigned long d_ino; if (buf->result) return -EINVAL; d_ino = ino; if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) { buf->result = -EOVERFLOW; return -EOVERFLOW; } 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(d_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; } SYSCALL_DEFINE3(old_readdir, unsigned int, fd, struct old_linux_dirent __user *, dirent, unsigned int, count) { int error; struct fd f = fdget(fd); struct readdir_callback buf = { .ctx.actor = fillonedir, .dirent = dirent }; if (!f.file) return -EBADF; error = iterate_dir(f.file, &buf.ctx); if (buf.result) error = buf.result; fdput(f); 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 dir_context ctx; struct linux_dirent __user * current_dir; struct linux_dirent __user * previous; int count; int error; }; static int filldir(struct dir_context *ctx, const char *name, int namlen, loff_t offset, u64 ino, unsigned int d_type) { struct linux_dirent __user * dirent; struct getdents_callback *buf = container_of(ctx, struct getdents_callback, ctx); unsigned long d_ino; int reclen = ALIGN(offsetof(struct linux_dirent, d_name) + namlen + 2, sizeof(long)); buf->error = -EINVAL; /* only used if we fail.. */ if (reclen > buf->count) return -EINVAL; d_ino = ino; if (sizeof(d_ino) < sizeof(ino) && d_ino != ino) { buf->error = -EOVERFLOW; return -EOVERFLOW; } dirent = buf->previous; if (dirent) { if (__put_user(offset, &dirent->d_off)) goto efault; } dirent = buf->current_dir; if (__put_user(d_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; } SYSCALL_DEFINE3(getdents, unsigned int, fd, struct linux_dirent __user *, dirent, unsigned int, count) { struct fd f; struct linux_dirent __user * lastdirent; struct getdents_callback buf = { .ctx.actor = filldir, .count = count, .current_dir = dirent }; int error; if (!access_ok(VERIFY_WRITE, dirent, count)) return -EFAULT; f = fdget(fd); if (!f.file) return -EBADF; error = iterate_dir(f.file, &buf.ctx); if (error >= 0) error = buf.error; lastdirent = buf.previous; if (lastdirent) { if (put_user(buf.ctx.pos, &lastdirent->d_off)) error = -EFAULT; else error = count - buf.count; } fdput(f); return error; } struct getdents_callback64 { struct dir_context ctx; struct linux_dirent64 __user * current_dir; struct linux_dirent64 __user * previous; int count; int error; }; static int filldir64(struct dir_context *ctx, const char *name, int namlen, loff_t offset, u64 ino, unsigned int d_type) { struct linux_dirent64 __user *dirent; struct getdents_callback64 *buf = container_of(ctx, struct getdents_callback64, ctx); int reclen = ALIGN(offsetof(struct linux_dirent64, d_name) + namlen + 1, sizeof(u64)); 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; } SYSCALL_DEFINE3(getdents64, unsigned int, fd, struct linux_dirent64 __user *, dirent, unsigned int, count) { struct fd f; struct linux_dirent64 __user * lastdirent; struct getdents_callback64 buf = { .ctx.actor = filldir64, .count = count, .current_dir = dirent }; int error; if (!access_ok(VERIFY_WRITE, dirent, count)) return -EFAULT; f = fdget(fd); if (!f.file) return -EBADF; error = iterate_dir(f.file, &buf.ctx); if (error >= 0) error = buf.error; lastdirent = buf.previous; if (lastdirent) { typeof(lastdirent->d_off) d_off = buf.ctx.pos; if (__put_user(d_off, &lastdirent->d_off)) error = -EFAULT; else error = count - buf.count; } fdput(f); return error; }