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6d7e8eda 1/* Copyright (C) 1991-2023 Free Software Foundation, Inc.
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2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
febb44a4 15 License along with the GNU C Library; see the file COPYING.LIB. If
5a82c748 16 not, see <https://www.gnu.org/licenses/>. */
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17
18#include <unistd.h>
19#include <hurd.h>
20#include <hurd/paths.h>
21#include <hurd/fd.h>
22#include <fcntl.h>
23#include <string.h>
24
25/* Read the contents of the symbolic link FILE_NAME relative to FD into no more
26 than LEN bytes of BUF. The contents are not null-terminated.
27 Returns the number of characters read, or -1 for errors. */
28ssize_t
7ae60af7 29__readlinkat (int fd, const char *file_name, char *buf, size_t len)
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30{
31 error_t err;
5652e12c 32 file_t file_stat;
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33 struct stat64 st;
34
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35 file_stat = __file_name_lookup_at (fd, 0, file_name, O_NOLINK, 0);
36 if (file_stat == MACH_PORT_NULL)
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37 return -1;
38
5652e12c 39 err = __io_stat (file_stat, &st);
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40 if (! err)
41 if (S_ISLNK (st.st_mode))
42 {
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43 enum retry_type doretry;
44 char retryname[1024];
45 file_t file;
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46 char *rbuf = buf;
47
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48 err = __dir_lookup (file_stat, "", O_READ | O_NOLINK, 0, &doretry, retryname, &file);
49 if (! err && (doretry != FS_RETRY_NORMAL || retryname[0] != '\0'))
50 err = EGRATUITOUS;
51 if (! err)
b29d4053 52 {
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53 err = __io_read (file, &rbuf, &len, 0, len);
54 if (!err && rbuf != buf)
55 {
56 memcpy (buf, rbuf, len);
57 __vm_deallocate (__mach_task_self (), (vm_address_t)rbuf, len);
58 }
59
60 __mach_port_deallocate (__mach_task_self (), file);
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61 }
62 }
63 else
64 err = EINVAL;
65
5652e12c 66 __mach_port_deallocate (__mach_task_self (), file_stat);
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67
68 return err ? __hurd_fail (err) : len;
69}
7ae60af7 70weak_alias (__readlinkat, readlinkat)
b29d4053 71libc_hidden_def (readlinkat)