557 lines
14 KiB
C++
557 lines
14 KiB
C++
/* ntea.cc: code for manipulating Extended Attributes
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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 "tls_pbuf.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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CV 2014-04-04: NtQueryEaFile function chokes on buffers bigger than 64K
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with STATUS_INVALID_PARAMETER if the handle points to a file
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on a remote share, at least on Windows 7 and later.
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In theory the buffer should have a size of
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sizeof (FILE_FULL_EA_INFORMATION) + MAX_EA_NAME_LEN
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+ MAX_EA_VALUE_LEN
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(65804 bytes), but we're opting for simplicity here, and
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a 64K buffer has the advantage that we can use a tmp_pathbuf
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buffer, rather than having to alloca 64K from stack. */
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#define EA_BUFSIZ 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 __reg3
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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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tmp_pathbuf tp;
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/* We have to store the latest EaName to compare with the next one, since
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NtQueryEaFile 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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__try
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{
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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,
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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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__leave;
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}
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}
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fea = (PFILE_FULL_EA_INFORMATION) tp.w_get ();
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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 ENOTSUP 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 (ENOTSUP);
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__leave;
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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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__leave;
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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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pc.init_reopen_attr (attr, h);
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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,
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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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switch (status)
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{
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case STATUS_NO_EAS_ON_FILE:
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ret = 0;
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break;
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case STATUS_INVALID_DEVICE_REQUEST:
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set_errno (ENOTSUP);
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break;
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case STATUS_NOT_FOUND:
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/* STATUS_NOT_FOUND is returned when calling NtQueryEaFile on NFS.
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In theory this should mean that the file just has no EAs, but
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in fact NFS doesn't support EAs, other than the EAs which are
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used for NFS requests. We're playing safe and convert
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STATUS_NOT_FOUND to ENOATTR, unless we're on NFS, where we
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convert it to ENOTSUP. */
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set_errno (pc.fs_is_nfs () ? ENOTSUP : ENOATTR);
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break;
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case STATUS_NONEXISTENT_EA_ENTRY:
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/* Actually STATUS_NONEXISTENT_EA_ENTRY is either never generated,
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or it was only generated in some old and long forgotton NT
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version. See below. For safty reasons, we handle it here,
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nevertheless. */
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set_errno (ENOATTR);
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break;
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default:
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__seterrno_from_nt_status (status);
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break;
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}
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__leave;
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}
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if (name)
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{
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/* Another weird behaviour of NtQueryEaFile. 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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NtQueryEaFile 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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__leave;
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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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__leave;
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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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fea->EaNameLength += 5; /* "user." */
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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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__leave;
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}
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/* For compatibility with Linux, we always prepend "user." to
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the attribute name, so effectively we only support user
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attributes from a application point of view. */
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char tmpbuf[MAX_EA_NAME_LEN * 2];
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char *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
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keep compatibility with ext/xfs EA namespaces and
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accompanying tools, which expect the namespaces to be
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lower case, we return EA names in lowercase if the file
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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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}
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__except (EFAULT) {}
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__endtry
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if (!hdl && h)
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NtClose (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 __reg3
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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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__try
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{
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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,
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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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__leave;
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}
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}
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/* For compatibility with Linux, we only allow user xattrs and
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return ENOTSUP otherwise. */
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if (!ascii_strncasematch (name, "user.", 5))
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{
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set_errno (ENOTSUP);
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__leave;
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}
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/* removexattr is supposed to fail with ENOATTR if the requested EA is
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not available. This is equivalent to XATTR_REPLACE 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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__leave;
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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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__leave;
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}
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if (flags == XATTR_REPLACE && rret < 0)
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__leave;
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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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__leave;
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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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pc.init_reopen_attr (attr, h);
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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,
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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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switch (status)
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{
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case STATUS_EA_TOO_LARGE:
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/* STATUS_EA_TOO_LARGE has a matching Win32 error code
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ERROR_EA_TABLE_FULL. For some reason RtlNtStatusToDosError
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does not translate STATUS_EA_TOO_LARGE to ERROR_EA_TABLE_FULL,
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but instead to ERROR_EA_LIST_INCONSISTENT. This error code is
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also returned for STATUS_EA_LIST_INCONSISTENT, which means the
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incoming EA list is... inconsistent. For obvious reasons we
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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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set_errno (ENOSPC);
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break;
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case STATUS_INVALID_DEVICE_REQUEST:
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set_errno (ENOTSUP);
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break;
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default:
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__seterrno_from_nt_status (status);
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break;
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}
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}
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else
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ret = 0;
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}
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__except (EFAULT) {}
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__endtry
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if (!hdl && h)
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NtClose (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 path_conv", 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 path_conv", 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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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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{
|
|
path_conv pc (path, PC_SYM_FOLLOW | PC_POSIX, stat_suffixes);
|
|
return setxattr_worker (pc, name, NULL, 0, 0);
|
|
}
|
|
|
|
extern "C" int
|
|
lremovexattr (const char *path, const char *name)
|
|
{
|
|
path_conv pc (path, PC_SYM_NOFOLLOW | PC_POSIX, stat_suffixes);
|
|
return setxattr_worker (pc, name, NULL, 0, 0);
|
|
}
|
|
|
|
extern "C" int
|
|
fremovexattr (int fd, const char *name)
|
|
{
|
|
int res;
|
|
|
|
cygheap_fdget cfd (fd);
|
|
if (cfd < 0)
|
|
res = -1;
|
|
else
|
|
res = cfd->fsetxattr (name, NULL, 0, 0);
|
|
return res;
|
|
}
|