1/* Copyright (C) 1991-2022 Free Software Foundation, Inc.
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
15 License along with the GNU C Library; if not, see
16 <https://www.gnu.org/licenses/>. */
17
18#include <errno.h>
19#include <stddef.h>
20#include <unistd.h>
21#include <limits.h>
22#include <sys/stat.h>
23#include <sys/statfs.h>
24#include <sys/statvfs.h>
25
26
27/* Get file-specific information about descriptor FD. */
28long int
29__fpathconf (int fd, int name)
30{
31 if (fd < 0)
32 {
33 __set_errno (EBADF);
34 return -1;
35 }
36
37 switch (name)
38 {
39 default:
40 __set_errno (EINVAL);
41 return -1;
42
43 case _PC_LINK_MAX:
44#ifdef LINK_MAX
45 return LINK_MAX;
46#else
47 return -1;
48#endif
49
50 case _PC_MAX_CANON:
51#ifdef MAX_CANON
52 return MAX_CANON;
53#else
54 return -1;
55#endif
56
57 case _PC_MAX_INPUT:
58#ifdef MAX_INPUT
59 return MAX_INPUT;
60#else
61 return -1;
62#endif
63
64 case _PC_NAME_MAX:
65#ifdef NAME_MAX
66 {
67 struct statvfs64 sv;
68 int save_errno = errno;
69
70 if (__fstatvfs64 (fd, &sv) < 0)
71 {
72 if (errno == ENOSYS)
73 {
74 __set_errno (save_errno);
75 return NAME_MAX;
76 }
77 else if (errno == ENODEV)
78 __set_errno (EINVAL);
79
80 return -1;
81 }
82 else
83 {
84 return sv.f_namemax;
85 }
86 }
87#else
88 return -1;
89#endif
90
91 case _PC_PATH_MAX:
92#ifdef PATH_MAX
93 return PATH_MAX;
94#else
95 return -1;
96#endif
97
98 case _PC_PIPE_BUF:
99#ifdef PIPE_BUF
100 return PIPE_BUF;
101#else
102 return -1;
103#endif
104
105 case _PC_CHOWN_RESTRICTED:
106#if _POSIX_CHOWN_RESTRICTED == -1
107# error "Invalid value for _POSIX_CHOWN_RESTRICTED"
108#endif
109 return _POSIX_CHOWN_RESTRICTED;
110
111 case _PC_NO_TRUNC:
112#if _POSIX_NO_TRUNC == -1
113# error "Invalid value for _POSIX_NO_TRUNC"
114#endif
115 return _POSIX_NO_TRUNC;
116
117 case _PC_VDISABLE:
118#if _POSIX_VDISABLE == -1
119# error "Invalid value for _POSIX_VDISABLE"
120#endif
121 return _POSIX_VDISABLE;
122
123 case _PC_SYNC_IO:
124#ifdef _POSIX_SYNC_IO
125 return _POSIX_SYNC_IO;
126#else
127 return -1;
128#endif
129
130 case _PC_ASYNC_IO:
131#ifdef _POSIX_ASYNC_IO
132 {
133 /* AIO is only allowed on regular files and block devices. */
134 struct __stat64_t64 st;
135
136 if (__fstat64_time64 (fd, &st) < 0
137 || (! S_ISREG (st.st_mode) && ! S_ISBLK (st.st_mode)))
138 return -1;
139 else
140 return 1;
141 }
142#else
143 return -1;
144#endif
145
146 case _PC_PRIO_IO:
147#ifdef _POSIX_PRIO_IO
148 return _POSIX_PRIO_IO;
149#else
150 return -1;
151#endif
152
153 case _PC_SOCK_MAXBUF:
154#ifdef SOCK_MAXBUF
155 return SOCK_MAXBUF;
156#else
157 return -1;
158#endif
159
160 case _PC_FILESIZEBITS:
161#ifdef FILESIZEBITS
162 return FILESIZEBITS;
163#else
164 /* We let platforms with larger file sizes overwrite this value. */
165 return 32;
166#endif
167
168 case _PC_REC_INCR_XFER_SIZE:
169 /* XXX It is not entirely clear what the limit is supposed to do.
170 What is incremented? */
171 return -1;
172
173 case _PC_REC_MAX_XFER_SIZE:
174 /* XXX It is not entirely clear what the limit is supposed to do.
175 In general there is no top limit of the number of bytes which
176 case be transported at once. */
177 return -1;
178
179 case _PC_REC_MIN_XFER_SIZE:
180 {
181 /* XXX It is not entirely clear what the limit is supposed to do.
182 I assume this is the block size of the filesystem. */
183 struct statvfs64 sv;
184
185 if (__fstatvfs64 (fd, &sv) < 0)
186 return -1;
187 return sv.f_bsize;
188 }
189
190 case _PC_REC_XFER_ALIGN:
191 {
192 /* XXX It is not entirely clear what the limit is supposed to do.
193 I assume that the number should reflect the minimal block
194 alignment. */
195 struct statvfs64 sv;
196
197 if (__fstatvfs64 (fd, &sv) < 0)
198 return -1;
199 return sv.f_frsize;
200 }
201
202 case _PC_ALLOC_SIZE_MIN:
203 {
204 /* XXX It is not entirely clear what the limit is supposed to do.
205 I assume that the number should reflect the minimal block
206 alignment. */
207 struct statvfs64 sv;
208
209 if (__fstatvfs64 (fd, &sv) < 0)
210 return -1;
211 return sv.f_frsize;
212 }
213
214 case _PC_SYMLINK_MAX:
215 /* In general there are no limits. If a system has one it should
216 overwrite this case. */
217 return -1;
218
219 case _PC_2_SYMLINKS:
220 /* Unix systems generally have symlinks. */
221 return 1;
222 }
223}
224
225#undef __fpathconf
226weak_alias (__fpathconf, fpathconf)
227

source code of glibc/sysdeps/posix/fpathconf.c