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authorDean Deng <deandeng@google.com>2020-02-10 14:47:00 -0800
committergVisor bot <gvisor-bot@google.com>2020-02-10 14:47:47 -0800
commit475316e87dac806d69bcb06ea4065f3c138bb47e (patch)
treef4dbb10404a2d3a08ee6b327b474543979808477 /pkg/sentry/syscalls
parentafcab8fe9f6fb3504ebdbb95d35299277c2d67ca (diff)
Refactor getxattr.
Put most of the logic for getxattr in one place for clarity. This simplifies FGetXattr and getXattrFromPath, which are just wrappers for getXattr. PiperOrigin-RevId: 294308332
Diffstat (limited to 'pkg/sentry/syscalls')
-rw-r--r--pkg/sentry/syscalls/linux/sys_xattr.go44
1 files changed, 20 insertions, 24 deletions
diff --git a/pkg/sentry/syscalls/linux/sys_xattr.go b/pkg/sentry/syscalls/linux/sys_xattr.go
index 342337726..9d8140b8a 100644
--- a/pkg/sentry/syscalls/linux/sys_xattr.go
+++ b/pkg/sentry/syscalls/linux/sys_xattr.go
@@ -49,14 +49,11 @@ func FGetXattr(t *kernel.Task, args arch.SyscallArguments) (uintptr, *kernel.Sys
}
defer f.DecRef()
- n, value, err := getXattr(t, f.Dirent, nameAddr, size)
+ n, err := getXattr(t, f.Dirent, nameAddr, valueAddr, size)
if err != nil {
return 0, nil, err
}
- if _, err := t.CopyOutBytes(valueAddr, []byte(value)); err != nil {
- return 0, nil, err
- }
return uintptr(n), nil, nil
}
@@ -71,41 +68,36 @@ func getXattrFromPath(t *kernel.Task, args arch.SyscallArguments, resolveSymlink
return 0, nil, err
}
- valueLen := 0
+ n := 0
err = fileOpOn(t, linux.AT_FDCWD, path, resolveSymlink, func(_ *fs.Dirent, d *fs.Dirent, _ uint) error {
if dirPath && !fs.IsDir(d.Inode.StableAttr) {
return syserror.ENOTDIR
}
- n, value, err := getXattr(t, d, nameAddr, size)
- valueLen = n
- if err != nil {
- return err
- }
-
- _, err = t.CopyOutBytes(valueAddr, []byte(value))
+ n, err = getXattr(t, d, nameAddr, valueAddr, size)
return err
})
if err != nil {
return 0, nil, err
}
- return uintptr(valueLen), nil, nil
+
+ return uintptr(n), nil, nil
}
// getXattr implements getxattr(2) from the given *fs.Dirent.
-func getXattr(t *kernel.Task, d *fs.Dirent, nameAddr usermem.Addr, size uint64) (int, string, error) {
- if err := checkXattrPermissions(t, d.Inode, fs.PermMask{Read: true}); err != nil {
- return 0, "", err
- }
-
+func getXattr(t *kernel.Task, d *fs.Dirent, nameAddr, valueAddr usermem.Addr, size uint64) (int, error) {
name, err := copyInXattrName(t, nameAddr)
if err != nil {
- return 0, "", err
+ return 0, err
+ }
+
+ if err := checkXattrPermissions(t, d.Inode, fs.PermMask{Read: true}); err != nil {
+ return 0, err
}
// TODO(b/148380782): Support xattrs in namespaces other than "user".
if !strings.HasPrefix(name, linux.XATTR_USER_PREFIX) {
- return 0, "", syserror.EOPNOTSUPP
+ return 0, syserror.EOPNOTSUPP
}
// If getxattr(2) is called with size 0, the size of the value will be
@@ -118,18 +110,22 @@ func getXattr(t *kernel.Task, d *fs.Dirent, nameAddr usermem.Addr, size uint64)
value, err := d.Inode.GetXattr(t, name, requestedSize)
if err != nil {
- return 0, "", err
+ return 0, err
}
n := len(value)
if uint64(n) > requestedSize {
- return 0, "", syserror.ERANGE
+ return 0, syserror.ERANGE
}
// Don't copy out the attribute value if size is 0.
if size == 0 {
- return n, "", nil
+ return n, nil
+ }
+
+ if _, err = t.CopyOutBytes(valueAddr, []byte(value)); err != nil {
+ return 0, err
}
- return n, value, nil
+ return n, nil
}
// SetXattr implements linux syscall setxattr(2).