diff options
author | Jamie Liu <jamieliu@google.com> | 2019-04-25 16:03:32 -0700 |
---|---|---|
committer | Shentubot <shentubot@google.com> | 2019-04-25 16:05:13 -0700 |
commit | 6b76c172b48ecb2c342882c0fe6474b2b973dad0 (patch) | |
tree | 61295be888beb8cb9c024aad03b9debe44fc2e32 /test/syscalls | |
parent | 72197810405a462386ded05d3c7c60c320289223 (diff) |
Don't enforce NAME_MAX in fs.Dirent.walk().
Maximum filename length is filesystem-dependent, and obtained via
statfs::f_namelen. This limit is usually 255 bytes (NAME_MAX), but not
always. For example, VFAT supports filenames of up to 255... UCS-2
characters, which Linux conservatively takes to mean UTF-8-encoded
bytes: fs/fat/inode.c:fat_statfs(), FAT_LFN_LEN * NLS_MAX_CHARSET_SIZE.
As a result, Linux's VFS does not enforce NAME_MAX:
$ rg --maxdepth=1 '\WNAME_MAX\W' fs/ include/linux/
fs/libfs.c
38: buf->f_namelen = NAME_MAX;
64: if (dentry->d_name.len > NAME_MAX)
include/linux/relay.h
74: char base_filename[NAME_MAX]; /* saved base filename */
include/linux/fscrypt.h
149: * filenames up to NAME_MAX bytes, since base64 encoding expands the length.
include/linux/exportfs.h
176: * understanding that it is already pointing to a a %NAME_MAX+1 sized
Remove this check from core VFS, and add it to ramfs (and by extension
tmpfs), where it is actually applicable:
mm/shmem.c:shmem_dir_inode_operations.lookup == simple_lookup *does*
enforce NAME_MAX.
PiperOrigin-RevId: 245324748
Change-Id: I17567c4324bfd60e31746a5270096e75db963fac
Diffstat (limited to 'test/syscalls')
-rw-r--r-- | test/syscalls/linux/chdir.cc | 5 | ||||
-rw-r--r-- | test/syscalls/linux/statfs.cc | 1 |
2 files changed, 1 insertions, 5 deletions
diff --git a/test/syscalls/linux/chdir.cc b/test/syscalls/linux/chdir.cc index 4905ffb23..a4b54f0ee 100644 --- a/test/syscalls/linux/chdir.cc +++ b/test/syscalls/linux/chdir.cc @@ -54,11 +54,6 @@ TEST(ChdirTest, NotDir) { EXPECT_THAT(chdir(temp_file.path().c_str()), SyscallFailsWithErrno(ENOTDIR)); } -TEST(ChdirTest, NameTooLong) { - std::string name(NAME_MAX + 1, 'a'); - ASSERT_THAT(chdir(name.c_str()), SyscallFailsWithErrno(ENAMETOOLONG)); -} - TEST(ChdirTest, NotExist) { EXPECT_THAT(chdir("/foo/bar"), SyscallFailsWithErrno(ENOENT)); } diff --git a/test/syscalls/linux/statfs.cc b/test/syscalls/linux/statfs.cc index 1fc9758c9..e1e7fc707 100644 --- a/test/syscalls/linux/statfs.cc +++ b/test/syscalls/linux/statfs.cc @@ -49,6 +49,7 @@ TEST(StatfsTest, NameLen) { struct statfs st; EXPECT_THAT(statfs("/dev/shm", &st), SyscallSucceeds()); + // This assumes that /dev/shm is tmpfs. EXPECT_EQ(st.f_namelen, NAME_MAX); } |