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 <fcntl.h>
23#include <sys/stat.h>
24#include <sys/statfs.h>
25#include <sys/statvfs.h>
26
27
28/* Get file-specific information about PATH. */
29long int
30__pathconf (const char *path, int name)
31{
32 if (path[0] == '\0')
33 {
34 __set_errno (ENOENT);
35 return -1;
36 }
37
38 switch (name)
39 {
40 default:
41 __set_errno (EINVAL);
42 return -1;
43
44 case _PC_LINK_MAX:
45#ifdef LINK_MAX
46 return LINK_MAX;
47#else
48 return -1;
49#endif
50
51 case _PC_MAX_CANON:
52#ifdef MAX_CANON
53 return MAX_CANON;
54#else
55 return -1;
56#endif
57
58 case _PC_MAX_INPUT:
59#ifdef MAX_INPUT
60 return MAX_INPUT;
61#else
62 return -1;
63#endif
64
65 case _PC_NAME_MAX:
66#ifdef NAME_MAX
67 {
68 struct statvfs64 sv;
69 int save_errno = errno;
70
71 if (__statvfs64 (path, &sv) < 0)
72 {
73 if (errno == ENOSYS)
74 {
75 errno = save_errno;
76 return NAME_MAX;
77 }
78 return -1;
79 }
80 else
81 {
82 return sv.f_namemax;
83 }
84 }
85#else
86 return -1;
87#endif
88
89 case _PC_PATH_MAX:
90#ifdef PATH_MAX
91 return PATH_MAX;
92#else
93 return -1;
94#endif
95
96 case _PC_PIPE_BUF:
97#ifdef PIPE_BUF
98 return PIPE_BUF;
99#else
100 return -1;
101#endif
102
103 case _PC_CHOWN_RESTRICTED:
104#if _POSIX_CHOWN_RESTRICTED == -1
105# error "Invalid value for _POSIX_CHOWN_RESTRICTED"
106#endif
107 return _POSIX_CHOWN_RESTRICTED;
108
109 case _PC_NO_TRUNC:
110#if _POSIX_NO_TRUNC == -1
111# error "Invalid value for _POSIX_NO_TRUNC"
112#endif
113 return _POSIX_NO_TRUNC;
114
115 case _PC_VDISABLE:
116#if _POSIX_VDISABLE == -1
117# error "Invalid value for _POSIX_VDISABLE"
118#endif
119 return _POSIX_VDISABLE;
120
121 case _PC_SYNC_IO:
122#ifdef _POSIX_SYNC_IO
123 return _POSIX_SYNC_IO;
124#else
125 return -1;
126#endif
127
128 case _PC_ASYNC_IO:
129#ifdef _POSIX_ASYNC_IO
130 {
131 /* AIO is only allowed on regular files and block devices. */
132 struct __stat64_t64 st;
133
134 if (__stat64_time64 (path, &st) < 0
135 || (! S_ISREG (st.st_mode) && ! S_ISBLK (st.st_mode)))
136 return -1;
137 else
138 return 1;
139 }
140#else
141 return -1;
142#endif
143
144 case _PC_PRIO_IO:
145#ifdef _POSIX_PRIO_IO
146 return _POSIX_PRIO_IO;
147#else
148 return -1;
149#endif
150
151 case _PC_SOCK_MAXBUF:
152#ifdef SOCK_MAXBUF
153 return SOCK_MAXBUF;
154#else
155 return -1;
156#endif
157
158 case _PC_FILESIZEBITS:
159#ifdef FILESIZEBITS
160 return FILESIZEBITS;
161#else
162 /* We let platforms with larger file sizes overwrite this value. */
163 return 32;
164#endif
165
166 case _PC_REC_INCR_XFER_SIZE:
167 /* XXX It is not entirely clear what the limit is supposed to do.
168 What is incremented? */
169 return -1;
170
171 case _PC_REC_MAX_XFER_SIZE:
172 /* XXX It is not entirely clear what the limit is supposed to do.
173 In general there is no top limit of the number of bytes which
174 case be transported at once. */
175 return -1;
176
177 case _PC_REC_MIN_XFER_SIZE:
178 {
179 /* XXX It is not entirely clear what the limit is supposed to do.
180 I assume this is the block size of the filesystem. */
181 struct statvfs64 sv;
182
183 if (__statvfs64 (path, &sv) < 0)
184 return -1;
185 return sv.f_bsize;
186 }
187
188 case _PC_REC_XFER_ALIGN:
189 {
190 /* XXX It is not entirely clear what the limit is supposed to do.
191 I assume that the number should reflect the minimal block
192 alignment. */
193 struct statvfs64 sv;
194
195 if (__statvfs64 (path, &sv) < 0)
196 return -1;
197 return sv.f_frsize;
198 }
199
200 case _PC_ALLOC_SIZE_MIN:
201 {
202 /* XXX It is not entirely clear what the limit is supposed to do.
203 I assume that the number should reflect the minimal block
204 alignment. */
205 struct statvfs64 sv;
206
207 if (__statvfs64 (path, &sv) < 0)
208 return -1;
209 return sv.f_frsize;
210 }
211
212 case _PC_SYMLINK_MAX:
213 /* In general there are no limits. If a system has one it should
214 overwrite this case. */
215 return -1;
216
217 case _PC_2_SYMLINKS:
218 /* Unix systems generally have symlinks. */
219 return 1;
220 }
221}
222
223#undef __pathconf
224weak_alias (__pathconf, pathconf)
225

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