7b426e9f4a
error codes. Always refuse non "user." EAs for Linux compatibility and return EOPNOTSUPP. Fix handling of empty (== non-existant) EAs. Always prepend "user." prefix to EA names. (write_ea): Try to open file first to have more sensible error codes. Always refuse non "user." EAs for Linux compatibility and return EOPNOTSUPP. Delay skipping "user." prefix until after potential call to read_ea.
516 lines
12 KiB
C++
516 lines
12 KiB
C++
/* ntea.cc: code for manipulating Extended Attributes
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Copyright 1997, 1998, 2000, 2001, 2006, 2008 Red Hat, Inc.
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This file is part of Cygwin.
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This software is a copyrighted work licensed under the terms of the
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Cygwin license. Please consult the file "CYGWIN_LICENSE" for
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details. */
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#include "winsup.h"
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#include "cygtls.h"
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#include "security.h"
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#include "path.h"
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#include "fhandler.h"
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#include "dtable.h"
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#include "cygheap.h"
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#include "ntdll.h"
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#include <stdlib.h>
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#include <attr/xattr.h>
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#define MAX_EA_NAME_LEN 256
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#define MAX_EA_VALUE_LEN 65536
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/* At least one maximum sized entry fits. */
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#define EA_BUFSIZ (sizeof (FILE_FULL_EA_INFORMATION) + MAX_EA_NAME_LEN \
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+ MAX_EA_VALUE_LEN)
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#define NEXT_FEA(p) ((PFILE_FULL_EA_INFORMATION) (p->NextEntryOffset \
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? (char *) p + p->NextEntryOffset : NULL))
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ssize_t __stdcall
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read_ea (HANDLE hdl, path_conv &pc, const char *name, char *value, size_t size)
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{
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OBJECT_ATTRIBUTES attr;
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NTSTATUS status;
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IO_STATUS_BLOCK io;
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ssize_t ret = -1;
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HANDLE h = hdl;
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ULONG glen = 0;
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PFILE_GET_EA_INFORMATION gea = NULL;
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PFILE_FULL_EA_INFORMATION fea;
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/* We have to store the latest EaName to compare with the next one, since
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ZwQueryEaFile has a bug when accessing files on a remote share. It
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returns the last EA entry of the file infinitely. Even utilizing the
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optional EaIndex only helps marginally. If you use that, the last
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EA in the file is returned twice. */
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char lastname[MAX_EA_NAME_LEN];
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myfault efault;
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if (efault.faulted (EFAULT))
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goto out;
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pc.get_object_attr (attr, sec_none_nih);
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debug_printf ("read_ea (%S, %s, %p, %lu)",
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attr.ObjectName, name, value, size);
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/* Early open if handle is NULL. This allows to return error codes like
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ENOENT before we actually check for the correctness of the EA name and
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stuff like that. */
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if (!hdl)
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{
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status = NtOpenFile (&h, READ_CONTROL | FILE_READ_EA, &attr, &io,
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FILE_SHARE_VALID_FLAGS, FILE_OPEN_FOR_BACKUP_INTENT);
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if (!NT_SUCCESS (status))
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{
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__seterrno_from_nt_status (status);
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goto out;
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}
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hdl = NULL;
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}
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fea = (PFILE_FULL_EA_INFORMATION) alloca (EA_BUFSIZ);
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if (name)
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{
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size_t nlen;
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/* For compatibility with Linux, we only allow user xattrs and
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return EOPNOTSUPP otherwise. */
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if (ascii_strncasematch (name, "user.", 5))
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name += 5;
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else
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{
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set_errno (EOPNOTSUPP);
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goto out;
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}
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if ((nlen = strlen (name)) >= MAX_EA_NAME_LEN)
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{
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set_errno (EINVAL);
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return -1;
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}
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glen = sizeof (FILE_GET_EA_INFORMATION) + nlen;
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gea = (PFILE_GET_EA_INFORMATION) alloca (glen);
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gea->NextEntryOffset = 0;
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gea->EaNameLength = nlen;
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strcpy (gea->EaName, name);
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}
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while (true)
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{
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if (h)
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{
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status = NtQueryEaFile (h, &io, fea, EA_BUFSIZ, TRUE, gea, glen,
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NULL, TRUE);
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if (status != STATUS_ACCESS_DENIED || !hdl)
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break;
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}
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status = NtOpenFile (&h, READ_CONTROL | FILE_READ_EA, &attr, &io,
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FILE_SHARE_VALID_FLAGS, FILE_OPEN_FOR_BACKUP_INTENT);
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if (!NT_SUCCESS (status))
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break;
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hdl = NULL;
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}
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if (!NT_SUCCESS (status))
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{
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if (status == STATUS_NO_EAS_ON_FILE)
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ret = 0;
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else if (status == STATUS_NONEXISTENT_EA_ENTRY)
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/* Actually this error code is either never generated, or it was only
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generated in some old and long forgotton NT version. See below. */
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set_errno (ENOATTR);
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else
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__seterrno_from_nt_status (status);
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goto out;
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}
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if (name)
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{
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/* Another weird behaviour of ZwQueryEaFile. If you ask for a
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specific EA which is not present in the file's EA list, you don't
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get a useful error code like STATUS_NONEXISTENT_EA_ENTRY. Rather
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ZwQueryEaFile returns success with the entry's EaValueLength
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set to 0. */
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if (!fea->EaValueLength)
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{
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set_errno (ENOATTR);
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goto out;
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}
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if (size > 0)
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{
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if (size < fea->EaValueLength)
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{
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set_errno (ERANGE);
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goto out;
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}
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memcpy (value, fea->EaName + fea->EaNameLength + 1,
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fea->EaValueLength);
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}
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ret = fea->EaValueLength;
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}
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else
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{
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ret = 0;
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do
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{
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if (pc.fs_is_samba ()) /* See below. */
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fea->EaNameLength += 5;
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if (size > 0)
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{
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if ((size_t) ret + fea->EaNameLength + 1 > size)
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{
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set_errno (ERANGE);
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goto out;
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}
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/* Samba hides the user namespace from Windows clients. We add
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it in EA listings to keep tools like attr/getfattr/setfattr
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happy. */
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char tmpbuf[MAX_EA_NAME_LEN * 2], *tp = tmpbuf;
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tp = stpcpy (tmpbuf, "user.");
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stpcpy (tp, fea->EaName);
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/* NTFS stores all EA names in uppercase unfortunately. To keep
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compatibility with ext/xfs EA namespaces and accompanying
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tools, which expect the namespaces to be lower case, we return
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EA names in lowercase if the file is on a native NTFS. */
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if (pc.fs_is_ntfs ())
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strlwr (tp);
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tp = stpcpy (value, tmpbuf) + 1;
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ret += tp - value;
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value = tp;
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}
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else
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ret += fea->EaNameLength + 1;
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strcpy (lastname, fea->EaName);
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status = NtQueryEaFile (h, &io, fea, EA_BUFSIZ, TRUE, NULL, 0,
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NULL, FALSE);
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}
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while (NT_SUCCESS (status) && strcmp (lastname, fea->EaName) != 0);
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}
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out:
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if (!hdl)
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CloseHandle (h);
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debug_printf ("%d = read_ea (%S, %s, %p, %lu)",
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ret, attr.ObjectName, name, value, size);
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return ret;
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}
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int __stdcall
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write_ea (HANDLE hdl, path_conv &pc, const char *name, const char *value,
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size_t size, int flags)
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{
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OBJECT_ATTRIBUTES attr;
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NTSTATUS status;
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IO_STATUS_BLOCK io;
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int ret = -1;
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HANDLE h = hdl;
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PFILE_FULL_EA_INFORMATION fea;
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ULONG flen;
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size_t nlen;
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myfault efault;
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if (efault.faulted (EFAULT))
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goto out;
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pc.get_object_attr (attr, sec_none_nih);
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debug_printf ("write_ea (%S, %s, %p, %lu, %d)",
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attr.ObjectName, name, value, size, flags);
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/* Early open if handle is NULL. This allows to return error codes like
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ENOENT before we actually check for the correctness of the EA name and
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stuff like that. */
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if (!hdl)
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{
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status = NtOpenFile (&h, READ_CONTROL | FILE_WRITE_EA, &attr, &io,
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FILE_SHARE_VALID_FLAGS, FILE_OPEN_FOR_BACKUP_INTENT);
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if (!NT_SUCCESS (status))
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{
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__seterrno_from_nt_status (status);
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goto out;
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}
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hdl = NULL;
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}
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/* For compatibility with Linux, we only allow user xattrs and
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return EOPNOTSUPP otherwise. */
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if (!ascii_strncasematch (name, "user.", 5))
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{
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set_errno (EOPNOTSUPP);
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goto out;
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}
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/* removexattr is supposed to fail with ENOATTR if the requested EA is not
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available. This is equivalent to the XATTR_REPLACE flag for setxattr. */
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if (!value)
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flags = XATTR_REPLACE;
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if (flags)
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{
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if (flags != XATTR_CREATE && flags != XATTR_REPLACE)
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{
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set_errno (EINVAL);
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goto out;
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}
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ssize_t rret = read_ea (hdl, pc, name, NULL, 0);
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if (flags == XATTR_CREATE && rret > 0)
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{
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set_errno (EEXIST);
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goto out;
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}
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if (flags == XATTR_REPLACE && rret < 0)
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goto out;
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}
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/* Skip "user." prefix. */
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name += 5;
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if ((nlen = strlen (name)) >= MAX_EA_NAME_LEN)
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{
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set_errno (EINVAL);
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goto out;
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}
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flen = sizeof (FILE_FULL_EA_INFORMATION) + nlen + 1 + size;
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fea = (PFILE_FULL_EA_INFORMATION) alloca (flen);
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fea->NextEntryOffset = 0;
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fea->Flags = 0;
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fea->EaNameLength = nlen;
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fea->EaValueLength = size;
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strcpy (fea->EaName, name);
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if (value)
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memcpy (fea->EaName + fea->EaNameLength + 1, value, size);
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while (true)
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{
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if (h)
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{
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status = NtSetEaFile (h, &io, fea, flen);
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if (status != STATUS_ACCESS_DENIED || !hdl)
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break;
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}
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status = NtOpenFile (&h, READ_CONTROL | FILE_WRITE_EA, &attr, &io,
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FILE_SHARE_VALID_FLAGS, FILE_OPEN_FOR_BACKUP_INTENT);
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if (!NT_SUCCESS (status))
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break;
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hdl = NULL;
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}
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if (!NT_SUCCESS (status))
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{
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/* STATUS_EA_TOO_LARGE has a matching Win32 error ERROR_EA_TABLE_FULL.
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Too bad RtlNtStatusToDosError does not translate STATUS_EA_TOO_LARGE
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to ERROR_EA_TABLE_FULL, but to ERROR_EA_LIST_INCONSISTENT. This
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error code is also returned for STATUS_EA_LIST_INCONSISTENT, which
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means the incoming EA list is... inconsistent. For obvious reasons
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we translate ERROR_EA_LIST_INCONSISTENT to EINVAL, so we have to
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handle STATUS_EA_TOO_LARGE explicitely here, to get the correct
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mapping to ENOSPC. */
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if (status == STATUS_EA_TOO_LARGE)
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set_errno (ENOSPC);
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else
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__seterrno_from_nt_status (status);
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}
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else
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ret = 0;
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out:
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if (!hdl)
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CloseHandle (h);
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debug_printf ("%d = write_ea (%S, %s, %p, %lu, %d)",
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ret, attr.ObjectName, name, value, size, flags);
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return ret;
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}
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static ssize_t __stdcall
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getxattr_worker (path_conv &pc, const char *name, void *value, size_t size)
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{
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int res = -1;
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if (pc.error)
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{
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debug_printf ("got %d error from build_fh_name", pc.error);
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set_errno (pc.error);
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}
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else if (pc.exists ())
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{
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fhandler_base *fh;
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if (!(fh = build_fh_pc (pc)))
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return -1;
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res = fh->fgetxattr (name, value, size);
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delete fh;
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}
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else
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set_errno (ENOENT);
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return res;
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}
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extern "C" ssize_t
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getxattr (const char *path, const char *name, void *value, size_t size)
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{
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if (!name)
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{
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set_errno (EINVAL);
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return -1;
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}
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path_conv pc (path, PC_SYM_FOLLOW | PC_POSIX, stat_suffixes);
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return getxattr_worker (pc, name, value, size);
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}
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extern "C" ssize_t
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lgetxattr (const char *path, const char *name, void *value, size_t size)
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{
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if (!name)
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{
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set_errno (EINVAL);
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return -1;
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}
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path_conv pc (path, PC_SYM_NOFOLLOW | PC_POSIX, stat_suffixes);
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return getxattr_worker (pc, name, value, size);
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}
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extern "C" ssize_t
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fgetxattr (int fd, const char *name, void *value, size_t size)
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{
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int res;
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if (!name)
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{
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set_errno (EINVAL);
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return -1;
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}
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cygheap_fdget cfd (fd);
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if (cfd < 0)
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res = -1;
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else
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res = cfd->fgetxattr (name, value, size);
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return res;
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}
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extern "C" ssize_t
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listxattr (const char *path, char *list, size_t size)
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{
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path_conv pc (path, PC_SYM_FOLLOW | PC_POSIX, stat_suffixes);
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return getxattr_worker (pc, NULL, list, size);
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}
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extern "C" ssize_t
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llistxattr (const char *path, char *list, size_t size)
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{
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path_conv pc (path, PC_SYM_NOFOLLOW | PC_POSIX, stat_suffixes);
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return getxattr_worker (pc, NULL, list, size);
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}
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extern "C" ssize_t
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flistxattr (int fd, char *list, size_t size)
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{
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int res;
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cygheap_fdget cfd (fd);
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if (cfd < 0)
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res = -1;
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else
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res = cfd->fgetxattr (NULL, list, size);
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return res;
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}
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static int __stdcall
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setxattr_worker (path_conv &pc, const char *name, const void *value,
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size_t size, int flags)
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{
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int res = -1;
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if (pc.error)
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{
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debug_printf ("got %d error from build_fh_name", pc.error);
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set_errno (pc.error);
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}
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else if (pc.exists ())
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{
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fhandler_base *fh;
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if (!(fh = build_fh_pc (pc)))
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return -1;
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res = fh->fsetxattr (name, value, size, flags);
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delete fh;
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}
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else
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set_errno (ENOENT);
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return res;
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}
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extern "C" int
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setxattr (const char *path, const char *name, const void *value, size_t size,
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int flags)
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{
|
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if (!size)
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{
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set_errno (EINVAL);
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return -1;
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}
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path_conv pc (path, PC_SYM_NOFOLLOW | PC_POSIX, stat_suffixes);
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return setxattr_worker (pc, name, value, size, flags);
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}
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extern "C" int
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lsetxattr (const char *path, const char *name, const void *value, size_t size,
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int flags)
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{
|
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if (!size)
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{
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set_errno (EINVAL);
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return -1;
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}
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path_conv pc (path, PC_SYM_NOFOLLOW | PC_POSIX, stat_suffixes);
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return setxattr_worker (pc, name, value, size, flags);
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}
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extern "C" int
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fsetxattr (int fd, const char *name, const void *value, size_t size, int flags)
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{
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int res;
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|
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if (!size)
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{
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set_errno (EINVAL);
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return -1;
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}
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cygheap_fdget cfd (fd);
|
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if (cfd < 0)
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res = -1;
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else
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res = cfd->fsetxattr (name, value, size, flags);
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return res;
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}
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extern "C" int
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removexattr (const char *path, const char *name)
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{
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path_conv pc (path, PC_SYM_FOLLOW | PC_POSIX, stat_suffixes);
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return setxattr_worker (pc, name, NULL, 0, 0);
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}
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extern "C" int
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lremovexattr (const char *path, const char *name)
|
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{
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path_conv pc (path, PC_SYM_NOFOLLOW | PC_POSIX, stat_suffixes);
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return setxattr_worker (pc, name, NULL, 0, 0);
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}
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extern "C" int
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fremovexattr (int fd, const char *name)
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{
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int res;
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cygheap_fdget cfd (fd);
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if (cfd < 0)
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res = -1;
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else
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res = cfd->fsetxattr (name, NULL, 0, 0);
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return res;
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}
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