Add support for fchdir and support cd for fish

demos/fish/fish_script.sh

@@ -1,3 +1,7 @@
 #! /usr/bin/fish
 command echo "Hello-world-from-fish" | awk '$1=$1' FS="-" OFS=" " > /root/output.txt
 cat /root/output.txt
+
+cd /opt/occlum/glibc/lib
+/usr/bin/busybox ls -al
+pwd

src/libos/Cargo.lock

@@ -411,7 +411,6 @@ dependencies = [
 name = "rcore-fs"
 version = "0.1.0"
 dependencies = [
- "bitflags",
  "spin",
 ]
 

src/libos/src/fs/file_ops/fspath.rs

@@ -94,7 +94,7 @@ impl<'a> Debug for FsPath<'a> {
 }
 
 /// Get the absolute path by file descriptor
-fn get_abs_path_by_fd(fd: FileDesc) -> Result<String> {
+pub fn get_abs_path_by_fd(fd: FileDesc) -> Result<String> {
     let path = {
         let file_ref = current!().file(fd)?;
         if let Ok(inode_file) = file_ref.as_inode_file() {

src/libos/src/fs/file_ops/mod.rs

@@ -10,7 +10,7 @@ pub use self::fallocate::do_fallocate;
 pub use self::fcntl::{do_fcntl, FcntlCmd};
 pub use self::file_flags::{AccessMode, CreationFlags, StatusFlags};
 pub use self::flock::{Flock, FlockType};
-pub use self::fspath::{FsPath, AT_FDCWD};
+pub use self::fspath::{get_abs_path_by_fd, FsPath, AT_FDCWD};
 pub use self::fsync::{do_fdatasync, do_fsync};
 pub use self::getdents::{do_getdents, do_getdents64};
 pub use self::ioctl::{

src/libos/src/fs/syscalls.rs

@@ -1,8 +1,8 @@
 use super::event_file::EventCreationFlags;
 use super::file_ops;
 use super::file_ops::{
-    AccessibilityCheckFlags, AccessibilityCheckMode, ChownFlags, FcntlCmd, FsPath, LinkFlags,
+    get_abs_path_by_fd, AccessibilityCheckFlags, AccessibilityCheckMode, ChownFlags, FcntlCmd,
-    StatFlags, UnlinkFlags, AT_FDCWD,
+    FsPath, LinkFlags, StatFlags, UnlinkFlags, AT_FDCWD,
 };
 use super::fs_ops;
 use super::time::{clockid_t, itimerspec_t, ClockID};
@@ -362,6 +362,12 @@ pub fn do_chdir(path: *const i8) -> Result<isize> {
     Ok(0)
 }
 
+pub fn do_fchdir(fd: FileDesc) -> Result<isize> {
+    let path = get_abs_path_by_fd(fd)?;
+    fs_ops::do_chdir(&path)?;
+    Ok(0)
+}
+
 pub fn do_getcwd(buf_ptr: *mut u8, size: usize) -> Result<isize> {
     let buf = {
         from_user::check_mut_array(buf_ptr, size)?;

src/libos/src/syscall/mod.rs

@@ -23,14 +23,14 @@ use util::mem_util::from_user::*;
 use crate::exception::do_handle_exception;
 use crate::fs::{
     do_access, do_chdir, do_chmod, do_chown, do_close, do_dup, do_dup2, do_dup3, do_eventfd,
-    do_eventfd2, do_faccessat, do_fallocate, do_fchmod, do_fchmodat, do_fchown, do_fchownat,
+    do_eventfd2, do_faccessat, do_fallocate, do_fchdir, do_fchmod, do_fchmodat, do_fchown,
-    do_fcntl, do_fdatasync, do_fstat, do_fstatat, do_fstatfs, do_fsync, do_ftruncate, do_getcwd,
+    do_fchownat, do_fcntl, do_fdatasync, do_fstat, do_fstatat, do_fstatfs, do_fsync, do_ftruncate,
-    do_getdents, do_getdents64, do_ioctl, do_lchown, do_link, do_linkat, do_lseek, do_lstat,
+    do_getcwd, do_getdents, do_getdents64, do_ioctl, do_lchown, do_link, do_linkat, do_lseek,
-    do_mkdir, do_mkdirat, do_mount_rootfs, do_open, do_openat, do_pipe, do_pipe2, do_pread,
+    do_lstat, do_mkdir, do_mkdirat, do_mount_rootfs, do_open, do_openat, do_pipe, do_pipe2,
-    do_pwrite, do_read, do_readlink, do_readlinkat, do_readv, do_rename, do_renameat, do_rmdir,
+    do_pread, do_pwrite, do_read, do_readlink, do_readlinkat, do_readv, do_rename, do_renameat,
-    do_sendfile, do_stat, do_statfs, do_symlink, do_symlinkat, do_sync, do_timerfd_create,
+    do_rmdir, do_sendfile, do_stat, do_statfs, do_symlink, do_symlinkat, do_sync,
-    do_timerfd_gettime, do_timerfd_settime, do_truncate, do_unlink, do_unlinkat, do_write,
+    do_timerfd_create, do_timerfd_gettime, do_timerfd_settime, do_truncate, do_unlink, do_unlinkat,
-    do_writev, iovec_t, AsTimer, File, FileDesc, FileRef, HostStdioFds, Stat, Statfs,
+    do_write, do_writev, iovec_t, AsTimer, File, FileDesc, FileRef, HostStdioFds, Stat, Statfs,
 };
 use crate::interrupt::{do_handle_interrupt, sgx_interrupt_info_t};
 use crate::misc::{resource_t, rlimit_t, sysinfo_t, utsname_t};
@@ -167,7 +167,7 @@ macro_rules! process_syscall_table_with_callback {
             (Getdents = 78) => do_getdents(fd: FileDesc, buf: *mut u8, buf_size: usize),
             (Getcwd = 79) => do_getcwd(buf: *mut u8, size: usize),
             (Chdir = 80) => do_chdir(path: *const i8),
-            (Fchdir = 81) => handle_unsupported(),
+            (Fchdir = 81) => do_fchdir(fd: FileDesc),
             (Rename = 82) => do_rename(oldpath: *const i8, newpath: *const i8),
             (Mkdir = 83) => do_mkdir(path: *const i8, mode: usize),
             (Rmdir = 84) => do_rmdir(path: *const i8),