diff options
| author | Nicolas Lacasse <nlacasse@google.com> | 2020-06-23 14:51:43 -0700 |
|---|---|---|
| committer | gVisor bot <gvisor-bot@google.com> | 2020-06-23 14:53:33 -0700 |
| commit | edea9a8d02d9877a05bb14046a26ebd9633f34f6 (patch) | |
| tree | 1bd258bb1f88d0b10564e718cb59d53137653e64 | |
| parent | ca1bc46f1540cdef2743bc2cae0eac89d0e61c69 (diff) | |
Port readahead to VFS2.
It preserves the same functionality (almost none) as in VFS1.
Updates #2923 #1035
PiperOrigin-RevId: 317943522
| -rw-r--r-- | pkg/sentry/syscalls/linux/vfs2/read_write.go | 33 | ||||
| -rw-r--r-- | pkg/sentry/syscalls/linux/vfs2/vfs2.go | 2 | ||||
| -rw-r--r-- | test/syscalls/BUILD | 1 |
3 files changed, 35 insertions, 1 deletions
diff --git a/pkg/sentry/syscalls/linux/vfs2/read_write.go b/pkg/sentry/syscalls/linux/vfs2/read_write.go index 7f9debd4a..cd25597a7 100644 --- a/pkg/sentry/syscalls/linux/vfs2/read_write.go +++ b/pkg/sentry/syscalls/linux/vfs2/read_write.go @@ -606,3 +606,36 @@ func Lseek(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Syscall newoff, err := file.Seek(t, offset, whence) return uintptr(newoff), nil, err } + +// Readahead implements readahead(2). +func Readahead(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.SyscallControl, error) { + fd := args[0].Int() + offset := args[1].Int64() + size := args[2].SizeT() + + file := t.GetFileVFS2(fd) + if file == nil { + return 0, nil, syserror.EBADF + } + defer file.DecRef() + + // Check that the file is readable. + if !file.IsReadable() { + return 0, nil, syserror.EBADF + } + + // Check that the size is valid. + if int(size) < 0 { + return 0, nil, syserror.EINVAL + } + + // Check that the offset is legitimate and does not overflow. + if offset < 0 || offset+int64(size) < 0 { + return 0, nil, syserror.EINVAL + } + + // Return EINVAL; if the underlying file type does not support readahead, + // then Linux will return EINVAL to indicate as much. In the future, we + // may extend this function to actually support readahead hints. + return 0, nil, syserror.EINVAL +} diff --git a/pkg/sentry/syscalls/linux/vfs2/vfs2.go b/pkg/sentry/syscalls/linux/vfs2/vfs2.go index b463edf2a..9e60c4a1c 100644 --- a/pkg/sentry/syscalls/linux/vfs2/vfs2.go +++ b/pkg/sentry/syscalls/linux/vfs2/vfs2.go @@ -92,7 +92,7 @@ func Override() { s.Table[162] = syscalls.Supported("sync", Sync) s.Table[165] = syscalls.Supported("mount", Mount) s.Table[166] = syscalls.Supported("umount2", Umount2) - delete(s.Table, 187) // readahead + s.Table[187] = syscalls.Supported("readahead", Readahead) s.Table[188] = syscalls.Supported("setxattr", Setxattr) s.Table[189] = syscalls.Supported("lsetxattr", Lsetxattr) s.Table[190] = syscalls.Supported("fsetxattr", Fsetxattr) diff --git a/test/syscalls/BUILD b/test/syscalls/BUILD index f94c383ae..8ce5d24f4 100644 --- a/test/syscalls/BUILD +++ b/test/syscalls/BUILD @@ -557,6 +557,7 @@ syscall_test( syscall_test( add_overlay = True, test = "//test/syscalls/linux:readahead_test", + vfs2 = "True", ) syscall_test( |