1/*
2 * Copyright (C) 2008 The Android Open Source Project
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 *  * Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 *  * Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in
12 *    the documentation and/or other materials provided with the
13 *    distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
16 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
17 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
18 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
19 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
21 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
22 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
23 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
24 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
25 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29#include <unistd.h>
30
31#include <errno.h>
32#include <sys/limits.h>
33#include <sys/vfs.h>
34
35static long __filesizebits(const struct statfs& s) {
36  switch (s.f_type) {
37    case JFFS2_SUPER_MAGIC:
38    case MSDOS_SUPER_MAGIC:
39    case NCP_SUPER_MAGIC:
40      return 32;
41  }
42  // There won't be any new 32-bit file systems.
43  return 64;
44}
45
46static long __link_max(const struct statfs& s) {
47  // These constant values were taken from kernel headers.
48  // They're not available in uapi headers.
49  switch (s.f_type) {
50    case EXT2_SUPER_MAGIC:
51      return 32000;
52    case MINIX_SUPER_MAGIC:
53      return 250;
54    case MINIX2_SUPER_MAGIC:
55      return 65530;
56    case REISERFS_SUPER_MAGIC:
57      return 0xffff - 1000;
58    case UFS_MAGIC:
59      return 32000;
60  }
61  return LINK_MAX;
62}
63
64static long __2_symlinks(const struct statfs& s) {
65  switch (s.f_type) {
66    case ADFS_SUPER_MAGIC:
67    case BFS_MAGIC:
68    case CRAMFS_MAGIC:
69    case EFS_SUPER_MAGIC:
70    case MSDOS_SUPER_MAGIC:
71    case QNX4_SUPER_MAGIC:
72      return 0;
73  }
74  return 1;
75}
76
77static long __pathconf(const struct statfs& s, int name) {
78  switch (name) {
79    case _PC_FILESIZEBITS:
80      return __filesizebits(s);
81
82    case _PC_LINK_MAX:
83      return __link_max(s);
84
85    case _PC_MAX_CANON:
86      return MAX_CANON;
87
88    case _PC_MAX_INPUT:
89      return MAX_INPUT;
90
91    case _PC_NAME_MAX:
92      return s.f_namelen;
93
94    case _PC_PATH_MAX:
95      return PATH_MAX;
96
97    case _PC_PIPE_BUF:
98      return PIPE_BUF;
99
100    case _PC_2_SYMLINKS:
101      return __2_symlinks(s);
102
103    case _PC_ALLOC_SIZE_MIN:  /* fall through */
104    case _PC_REC_XFER_ALIGN:
105      return s.f_frsize;
106
107    case _PC_REC_MIN_XFER_SIZE:
108      return s.f_bsize;
109
110#if 0
111    case _PC_REC_INCR_XFER_SIZE:
112    case _PC_REC_MAX_XFER_SIZE:
113#endif
114
115    case _PC_SYMLINK_MAX:
116      return -1; /* no limit */
117
118    case _PC_CHOWN_RESTRICTED:
119      return _POSIX_CHOWN_RESTRICTED;
120
121    case _PC_NO_TRUNC:
122      return _POSIX_NO_TRUNC;
123
124    case _PC_VDISABLE:
125      return _POSIX_VDISABLE;
126
127    case _PC_ASYNC_IO:
128      return -1;
129
130    case _PC_PRIO_IO:
131      return -1;
132
133    case _PC_SYNC_IO:
134      return -1;
135
136    default:
137      errno = EINVAL;
138      return -1;
139  }
140}
141
142long pathconf(const char* path, int name) {
143  struct statfs sb;
144  if (statfs(path, &sb) == -1) {
145    return -1;
146  }
147  return __pathconf(sb, name);
148}
149
150long fpathconf(int fd, int name) {
151  struct statfs sb;
152  if (fstatfs(fd, &sb) == -1) {
153    return -1;
154  }
155  return __pathconf(sb, name);
156}
157