Some FUSE callbacks, some POSIX interface implementation

1 files changed, 333 insertions, 185 deletions

diff --git a/src/filesystem/trait_impl.rs b/src/filesystem/trait_impl.rs
index a25a383..c533c41 100644
--- a/src/filesystem/trait_impl.rs
+++ b/src/filesystem/trait_impl.rs
@@ -1,67 +1,69 @@
-use crate::block_device::BLOCK_SIZE;
+
 use crate::disk::inode::InodeMode;
-use crate::utils::make_fileattr;
-use crate::{utils, AyaFS, TTL};
-use fuser::{
-    FileAttr, FileType, Filesystem, KernelConfig, ReplyAttr, ReplyData, ReplyDirectory, ReplyEmpty,
-    ReplyEntry, ReplyLseek, ReplyWrite, Request, TimeOrNow,
+use crate::utils::{from_systime, time_now, to_fileattr, to_filetype};
+use crate::utils::permissions::get_groups;
+use crate::{AyaFS, TTL};
+use fuser::{Filesystem, KernelConfig, ReplyAttr, ReplyData, ReplyDirectory, ReplyEmpty,
+            ReplyEntry, ReplyLseek, ReplyOpen, Request, TimeOrNow,
 };
-use libc::{c_int, ENAMETOOLONG, ENOENT, ENOSPC, ENOSYS, ENOTDIR};
+use libc::{c_int, EACCES, EEXIST, ENAMETOOLONG, ENOENT, ENOSPC, ENOSYS, ENOTDIR, EPERM, R_OK, S_ISGID, S_ISUID, S_IXGRP, S_IXOTH, S_IXUSR, W_OK};
 use log::debug;
 use std::ffi::OsStr;
-use std::os::unix::ffi::OsStrExt;
 use std::time::SystemTime;
-use users::{get_current_gid, get_current_uid};
+use fuser::TimeOrNow::{Now, SpecificTime};
+use crate::utils::permissions::{check_access, clear_suid_sgid};
+
+impl AyaFS {
+
+}
 
 impl Filesystem for AyaFS {
     fn init(&mut self, _req: &Request<'_>, _config: &mut KernelConfig) -> Result<(), c_int> {
-        debug!("Filesystem::init called.");
+        debug!("`init()");
         Ok(())
     }
 
     fn destroy(&mut self) {
-        debug!("Filesystem::destroy()");
+        debug!("destroy()");
+        // TODO 写回
     }
 
-    fn lookup(&mut self, _req: &Request<'_>, parent: u64, name: &OsStr, reply: ReplyEntry) {
-        let parent = parent as usize;
-        if let Some(inode) = self.get_inode(parent) {
-            // debug!("{:?}", inode);
+    fn lookup(&mut self, req: &Request<'_>, parent: u64, name: &OsStr, reply: ReplyEntry) {
+        if name.len() > 255 {
+            reply.error(ENAMETOOLONG);
+            return;
         }
-        // if self.inode_active(parent) {
-        //     let (block, offset) = self.locate_inode(parent);
-        //     let inode = self.get_inode(block, offset);
-        //     debug!("{:?}", inode);
-        // }
-        reply.error(ENOENT);
-    }
 
-    fn forget(&mut self, _req: &Request<'_>, _ino: u64, _nlookup: u64) {
-        debug!("Filesystem::forget()");
-        todo!("This is a dumb implementation")
+        let parent = parent as usize;
+        if let Some(parent_inode) = self.get_inode(parent) {
+            if check_access(
+                req.uid(),
+                req.gid(),
+                parent_inode.uid,
+                parent_inode.gid,
+                parent_inode.mode,
+                R_OK
+            ) {
+                let parent_inode = parent_inode.clone();
+                match self.lookup_name(&parent_inode, name) {
+                    Ok((inode_index, inode)) => {
+                        let attr = to_fileattr(inode_index as usize, &inode);
+                        reply.entry(&TTL, &attr, 0);
+                    },
+                    Err(err_code) => reply.error(err_code)
+                };
+            } else {
+                reply.error(EACCES);
+            }
+        } else {
+            reply.error(ENOENT);
+        }
     }
 
     fn getattr(&mut self, _req: &Request<'_>, ino: u64, reply: ReplyAttr) {
         debug!("Filesystem::getattr(ino: {})", ino);
         if let Some(inode) = self.get_inode(ino as usize) {
-            let attr = FileAttr {
-                ino,
-                size: inode.size as u64,
-                blocks: inode.n_blocks as u64,
-                atime: utils::to_systime(inode.atime),
-                mtime: utils::to_systime(inode.mtime),
-                ctime: utils::to_systime(inode.ctime),
-                crtime: utils::to_systime(inode.crtime),
-                kind: inode.mode.into(),
-                perm: inode.mode.perm(),
-                nlink: inode.n_links as u32,
-                uid: inode.uid,
-                gid: inode.gid,
-                rdev: 0,
-                blksize: BLOCK_SIZE as u32,
-                flags: inode.flags,
-            };
-            reply.attr(&TTL, &attr);
+            reply.attr(&TTL, &to_fileattr(ino as usize, inode));
         } else {
             reply.error(ENOENT);
         }
@@ -69,96 +71,159 @@ impl Filesystem for AyaFS {
 
     fn setattr(
         &mut self,
-        _req: &Request<'_>,
+        req: &Request<'_>,
         ino: u64,
         mode: Option<u32>,
         uid: Option<u32>,
         gid: Option<u32>,
-        size: Option<u64>, // TODO 为什么 setattr 还可以设置 size??
+        size: Option<u64>, // TODO 当 setattr 被 ftruncate invoke 时会设置 size
         atime: Option<TimeOrNow>,
         mtime: Option<TimeOrNow>,
-        ctime: Option<SystemTime>,
-        fh: Option<u64>,
-        crtime: Option<SystemTime>,
-        _chgtime: Option<SystemTime>,
-        _bkuptime: Option<SystemTime>,
-        flags: Option<u32>,
+        _ctime: Option<SystemTime>,
+        fh: Option<u64>, // TODO 当 setattr 被 ftruncate invoke 时会提供 fh
+        _crtime: Option<SystemTime>, // 忽略
+        _chgtime: Option<SystemTime>, // 忽略
+        _bkuptime: Option<SystemTime>, // 忽略
+        _flags: Option<u32>, // 忽略
         reply: ReplyAttr,
     ) {
         if let Some(inode) = self.get_inode_mut(ino as usize) {
-            let mode = mode
-                .and_then(|mode_value| {
-                    InodeMode::validate(mode_value as u16) // high 16 bit truncated
-                })
-                .unwrap_or(inode.mode);
-            inode.mode = mode;
-            // 如果传入的 InodeMode 是合法结果, 那么得到 Some(mode), 否则 None
-            // 需要检查权限吗? 如果需要, 如何知道 invoke 这个 callback 的 UID/GID?
-
-            let size = size.unwrap_or(inode.size as u64);
-            inode.size = size as u32;
-            // TODO 为什么可以设置 size 呢……
-
-            let uid = uid.unwrap_or(inode.uid);
-            let gid = gid.unwrap_or(inode.gid);
-            inode.uid = uid;
-            inode.gid = gid;
-
-            let (atime, atime_inner) = atime
-                .map(|atime| {
-                    let system_time = match atime {
-                        TimeOrNow::SpecificTime(system_time) => system_time,
-                        TimeOrNow::Now => SystemTime::now(),
+            // chmod
+            if let Some(mode) = mode {
+                debug!("chmod on inode {:#x?} mode {:o}", ino, mode);
+                if req.uid() != 0 && req.uid() != inode.uid {
+                    reply.error(EPERM);
+                    return;
+                } // uid == 0 (root) or uid == inode.uid (user itself)
+
+                if req.uid() != 0 && req.gid() != inode.gid && !get_groups(req.pid()).contains(&inode.gid) {
+                    inode.mode = InodeMode((mode & !S_ISGID) as u16);
+                } else {
+                    inode.mode = InodeMode(mode as u16);
+                }
+
+                inode.ctime = time_now();
+                reply.attr(&TTL, &to_fileattr(ino as usize, inode));
+                return;
+            }
+
+            // chown
+            if uid.is_some() || gid.is_some() {
+                debug!("chown on inode {:#x?} uid {:?} gid {:?}", ino, uid, gid);
+                if let Some(uid) = uid {
+                    // 虽然只有 root 可以 chown 但是 user chown 自己也是不报错的
+                    if req.uid() != 0 && !(uid == inode.uid && uid == req.uid()) {
+                        reply.error(EPERM);
+                        return;
+                    }
+                }
+                if let Some(gid) = gid {
+                    // 只有 root 和 file owner 才可以 chgrp
+                    if req.uid() != 0 && req.uid() != inode.uid {
+                        reply.error(EPERM);
+                        return;
+                    }
+                    // root 可以任意 chgrp, 非 root 只能修改到用户自己所在的组里
+                    if req.gid() != 0 && !get_groups(req.pid()).contains(&gid) {
+                        reply.error(EPERM);
+                        return;
+                    }
+                }
+
+                // 可执行文件要清除 suid & sgid
+                if inode.mode.0 & (S_IXUSR | S_IXGRP | S_IXOTH) as u16 != 0 {
+                    inode.mode = clear_suid_sgid(inode.mode);
+                }
+
+                // chown 要清除 suid
+                if let Some(uid) = uid {
+                    inode.uid = uid;
+                    inode.mode.0 &= !S_ISUID as u16;
+                }
+
+                if let Some(gid) = gid {
+                    inode.gid = gid;
+                    if req.uid() != 0 {
+                        inode.mode.0 &= !S_ISGID as u16;
+                    }
+                }
+                inode.ctime = time_now();
+                reply.attr(&TTL, &to_fileattr(ino as usize, inode));
+                return;
+            }
+
+            // ftruncate
+            if let Some(size) = size {
+                debug!("ftruncate on inode {:#x?} size {:?}", ino, size);
+                if let Some(file_handle) = fh {
+                    // 有 file handle 的
+                    todo!()
+                } else {
+                    // 没有 file handle 基于 inode 的
+                    todo!()
+                }
+            }
+
+            // time 相关
+            if atime.is_some() || mtime.is_some() {
+                let current_time = time_now();
+                if let Some(atime) = atime {
+                    debug!("utimensat on inode {:#x?}, atime {:?}", ino, atime);
+                    // root 和 user 可以随意修改 atime, 其他用户只能 touch (即 atime == Now)
+                    if req.uid() != 0 && req.uid() != inode.uid && atime != Now {
+                        reply.error(EPERM);
+                        return;
+                    }
+
+                    if req.uid() != 0 && req.uid() != inode.uid && check_access(
+                        req.uid(),
+                        req.gid(),
+                        inode.uid,
+                        inode.gid,
+                        inode.mode,
+                        R_OK, // atime 来说是 read TODO 对吗
+                    ) {
+                        reply.error(EACCES);
+                        return;
+                    }
+
+                    inode.atime = match atime {
+                        SpecificTime(time) => from_systime(time),
+                        Now => current_time,
                     };
-                    (system_time, utils::from_systime(system_time))
-                })
-                .unwrap_or((utils::to_systime(inode.atime), inode.atime));
-            inode.atime = atime_inner;
-
-            let (mtime, mtime_inner) = mtime
-                .map(|mtime| {
-                    let system_time = match mtime {
-                        TimeOrNow::SpecificTime(system_time) => system_time,
-                        TimeOrNow::Now => SystemTime::now(),
+                    inode.ctime = current_time;
+                }
+                if let Some(mtime) = mtime {
+                    debug!("utimensat on inode {:#x?}, mtime {:?}", ino, mtime);
+                    // root 和 user 可以随意修改 mtime, 其他用户只能 mtime == Now
+                    if req.uid() != 0 && req.uid() != inode.uid && mtime != Now {
+                        reply.error(EPERM);
+                        return;
+                    }
+
+                    if req.uid() != 0 && req.uid() != inode.uid && check_access(
+                        req.uid(),
+                        req.gid(),
+                        inode.uid,
+                        inode.gid,
+                        inode.mode,
+                        W_OK, // mtime 来说是 write
+                    ) {
+                        reply.error(EACCES);
+                        return;
+                    }
+
+                    inode.mtime = match mtime {
+                        SpecificTime(time) => from_systime(time),
+                        Now => current_time,
                     };
-                    (system_time, utils::from_systime(system_time))
-                })
-                .unwrap_or((utils::to_systime(inode.mtime), inode.mtime));
-            inode.mtime = mtime_inner;
-
-            let (ctime, ctime_inner) = ctime
-                .map(|ctime| (ctime, utils::from_systime(ctime)))
-                .unwrap_or((utils::to_systime(inode.ctime), inode.ctime));
-            inode.ctime = ctime_inner;
-
-            let (crtime, crtime_inner) = crtime
-                .map(|crtime| (crtime, utils::from_systime(crtime)))
-                .unwrap_or((utils::to_systime(inode.crtime), inode.crtime));
-            inode.crtime = crtime_inner;
-
-            let flags = flags.unwrap_or(inode.flags);
-            inode.flags = flags;
-
-            let attr = FileAttr {
-                ino,
-                size,
-                blocks: inode.n_blocks as u64,
-                atime,
-                mtime,
-                ctime,
-                crtime,
-                kind: mode.into(),
-                perm: mode.perm(),
-                nlink: inode.n_links as u32,
-                uid,
-                gid,
-                rdev: 0,
-                blksize: BLOCK_SIZE as u32,
-                flags,
-            };
-            reply.attr(&TTL, &attr);
+                    inode.ctime = current_time;
+                }
+            }
+            reply.attr(&TTL, &to_fileattr(ino as usize, inode));
+            return;
         } else {
-            reply.error(ENOSYS);
+            reply.error(ENOENT);
         }
     }
 
@@ -169,7 +234,7 @@ impl Filesystem for AyaFS {
 
     fn mknod(
         &mut self,
-        _req: &Request<'_>,
+        req: &Request<'_>,
         parent: u64,
         name: &OsStr,
         mode: u32,
@@ -181,33 +246,51 @@ impl Filesystem for AyaFS {
             "Filesystem::mknod(parent: {}, name: {:?}, mode: {}, umask: {})",
             parent, name, mode, _umask
         );
-        if let Some(inode) = self.get_inode(parent as usize) {
-            if inode.is_dir() {
-                let name = name.as_bytes();
-                if name.len() <= 255 {
-                    let permissions = (mode & 0o777) as u16;
-                    if let Some(inode_index) = self.create_inode(
-                        permissions,
-                        InodeMode::IFREG,
-                        get_current_uid(),
-                        get_current_gid(),
+
+        if let Some(parent_inode) = self.get_inode(parent as usize) {
+            if check_access(
+                req.uid(),
+                req.gid(),
+                parent_inode.uid,
+                parent_inode.gid,
+                parent_inode.mode,
+                W_OK
+            ) {
+                if parent_inode.is_dir() {
+                    let parent_inode = parent_inode.clone();
+                    // 如果已经存在, 返回 already exists
+                    if self.lookup_name(&parent_inode, name).is_ok() {
+                        reply.error(EEXIST);
+                        return;
+                    }
+                    // 文件名长度超过 255, 返回 filename too long
+                    if name.len() > 255 {
+                        reply.error(ENAMETOOLONG);
+                        return;
+                    }
+
+                    let mode = mode as u16;
+                    if let Some((inode_index, inode)) = self.create_file(
+                        mode,
+                        req.uid(),
+                        req.gid(),
                         0,
                     ) {
-                        let inode = self.get_inode(inode_index).unwrap();
-                        let file_attr = make_fileattr(inode_index, inode);
+                        let file_attr = to_fileattr(inode_index, inode);
                         // TODO 把 inode 挂到 parent 下
+                        self.update_inode(parent as usize, parent_inode);
+                        // 前面 clone 了, 这里写回
                         reply.entry(&TTL, &file_attr, 0);
                     } else {
                         // create_inode 失败 -> no enough space
                         reply.error(ENOSPC);
                     }
                 } else {
-                    // name 长度超过 255 -> File name too long
-                    reply.error(ENAMETOOLONG);
+                    // parent 不是 IFDIR -> Not a directory
+                    reply.error(ENOTDIR);
                 }
             } else {
-                // parent 不是 IFDIR -> Not a directory
-                reply.error(ENOTDIR);
+                reply.error(EACCES);
             }
         } else {
             // parent 不存在 -> No such file or directory
@@ -217,40 +300,57 @@ impl Filesystem for AyaFS {
 
     fn mkdir(
         &mut self,
-        _req: &Request<'_>,
+        req: &Request<'_>,
         parent: u64,
         name: &OsStr,
         mode: u32,
         _umask: u32, // umask 应该也是用不到的
         reply: ReplyEntry,
     ) {
-        if let Some(inode) = self.get_inode(parent as usize) {
-            if inode.is_dir() {
-                let name = name.as_bytes();
-                if name.len() <= 255 {
-                    let permissions = (mode & 0o777) as u16;
-                    if let Some(inode_index) = self.create_inode(
-                        permissions,
-                        InodeMode::IFDIR,
-                        get_current_uid(),
-                        get_current_gid(),
+        if let Some(parent_inode) = self.get_inode(parent as usize) {
+            if check_access(
+                req.uid(),
+                req.gid(),
+                parent_inode.uid,
+                parent_inode.gid,
+                parent_inode.mode,
+                W_OK
+            ) {
+                if parent_inode.is_dir() {
+                    let parent_inode = parent_inode.clone();
+                    // 如果已经存在, 返回 already exists
+                    if self.lookup_name(&parent_inode, name).is_ok() {
+                        reply.error(EEXIST);
+                        return;
+                    }
+                    // 文件名长度超过 255, 返回 filename too long
+                    if name.len() > 255 {
+                        reply.error(ENAMETOOLONG);
+                        return;
+                    }
+
+                    let mode = mode as u16;
+                    if let Some((inode_index, inode)) = self.create_directory(
+                        mode,
+                        req.uid(),
+                        req.gid(),
                         0,
                     ) {
-                        let inode = self.get_inode(inode_index).unwrap();
-                        let file_attr = make_fileattr(inode_index, inode);
+                        let file_attr = to_fileattr(inode_index, inode);
                         // TODO 把 inode 挂到 parent 下
+                        self.update_inode(parent as usize, parent_inode);
+                        // 前面 clone 了, 这里写回
                         reply.entry(&TTL, &file_attr, 0);
                     } else {
                         // create_inode 失败 -> no enough space
                         reply.error(ENOSPC);
                     }
                 } else {
-                    // name 长度超过 255 -> File name too long
-                    reply.error(ENAMETOOLONG);
+                    // parent 不是 IFDIR -> Not a directory
+                    reply.error(ENOTDIR);
                 }
             } else {
-                // parent 不是 IFDIR -> Not a directory
-                reply.error(ENOTDIR);
+                reply.error(EACCES);
             }
         } else {
             // parent 不存在 -> No such file or directory
@@ -259,13 +359,28 @@ impl Filesystem for AyaFS {
     }
 
     fn unlink(&mut self, _req: &Request<'_>, parent: u64, name: &OsStr, reply: ReplyEmpty) {
-        debug!(
-            "unlink(parent: {:#x?}, name: {:?})",
-            parent, name,
-        );
+        debug!("unlink(parent: {:#x?}, name: {:?})", parent, name,);
         if let Some(inode) = self.get_inode_mut(parent as usize) {
-            // TODO 找到这个 inode 并且删掉
-            reply.ok();
+            if inode.is_file() {
+                // TODO 找到这个 inode 并且删掉
+                reply.ok();
+            } else {
+                reply.error(ENOENT);
+            }
+        } else {
+            reply.error(ENOENT);
+        }
+    }
+
+    fn rmdir(&mut self, _req: &Request<'_>, parent: u64, name: &OsStr, reply: ReplyEmpty) {
+        debug!("rmdir(parent: {:#x?}, name: {:?}", parent, name,);
+        if let Some(inode) = self.get_inode_mut(parent as usize) {
+            if inode.is_file() {
+                // TODO 找到这个 inode 并且删掉
+                reply.ok();
+            } else {
+                reply.error(ENOTDIR);
+            }
         } else {
             reply.error(ENOENT);
         }
@@ -285,45 +400,78 @@ impl Filesystem for AyaFS {
         todo!()
     }
 
+    fn opendir(&mut self, _req: &Request<'_>, ino: u64, flags: i32, reply: ReplyOpen) {
+        debug!("OPENDIR ino {:#x} flags {}", ino, flags);
+        reply.opened(1, 0);
+    }
+
     fn readdir(
         &mut self,
-        _req: &Request<'_>,
+        req: &Request<'_>,
         ino: u64,
-        _fh: u64,
+        _fh: u64, // 如果 invoke 它的 opendir 里有指定 fh, 那么这里会收到 fh 参数
         offset: i64,
         mut reply: ReplyDirectory,
     ) {
         if let Some(inode) = self.get_inode(ino as usize) {
+            if inode.is_dir() {
+                if check_access(
+                    req.uid(),
+                    req.gid(),
+                    inode.uid,
+                    inode.gid,
+                    inode.mode,
+                    R_OK,
+                ) {
+                    let inode = inode.clone();
+                    let mut entry_index = offset as u32;
+
+                    while let Some(dir_entry) = self.get_direntry(&inode, entry_index) {
+                        debug!("reading inode {:#x} index {}", ino, entry_index);
+                        if entry_index >= inode.size {
+                            break;
+                        }
+                        // 最开头应该添加 `.` 和 `..`, 但这件事应该在 mkdir 的时候就在 inode 里加好
+                        // reply.add 返回 true 说明 buffer 已满, 停止累加
+                        if reply.add(
+                            dir_entry.inode as u64,
+                            entry_index as i64,
+                            to_filetype(dir_entry.file_type).expect("file type should not be 0x0!"),
+                            dir_entry.name(),
+                        ) {
+                            break;
+                        }
+                        entry_index += 1;
+                    }
+                    reply.ok();
+                } else {
+                    reply.error(EACCES);
+                }
+            } else {
+                reply.error(ENOTDIR);
+            }
         } else {
             reply.error(ENOENT);
         }
-
-        // if ino != 1 {
-        //     reply.error(ENOENT);
-        //     return;
-        // }
-        //
-        // let entries = vec![
-        //     (1, FileType::Directory, "."),
-        //     (1, FileType::Directory, ".."),
-        //     (2, FileType::RegularFile, "hello.txt"),
-        // ];
-        //
-        // for (i, entry) in entries.into_iter().enumerate().skip(offset as usize) {
-        //     // i + 1 means the index of the next entry
-        //     if reply.add(entry.0, (i + 1) as i64, entry.1, entry.2) {
-        //         break;
-        //     }
-        // }
-        // reply.ok();
     }
 
-    fn access(&mut self, _req: &Request<'_>, ino: u64, mask: i32, reply: ReplyEmpty) {
+    fn access(&mut self, req: &Request<'_>, ino: u64, mask: i32, reply: ReplyEmpty) {
+        // mask:
+        // - 要么是 libc::F_OK (aka 0), 检查文件是否存在
+        // - 要么是 libc::R_OK,libc::W_OK,libc::X_OK (aka 4/2/1) 构成的 bitmask, 检查是否有对应权限
         debug!("Filesystem::getattr(ino: {}, mask: {})", ino, mask);
+
         if let Some(inode) = self.get_inode(ino as usize) {
-            reply.ok()
+            if mask == libc::F_OK // 只要检查是否存在
+                || check_access(req.uid(), req.gid(), inode.uid, inode.gid, inode.mode, mask)
+            // 需要检查 rwx 权限
+            {
+                reply.ok();
+            } else {
+                reply.error(EACCES);
+            }
         } else {
-            reply.error(ENOENT)
+            reply.error(ENOENT);
         }
     }