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a323afb2 JG |
1 | #ifndef _BABELTRACE_COMPAT_FCNTL_H |
2 | #define _BABELTRACE_COMPAT_FCNTL_H | |
3 | ||
4 | /* | |
5 | * babeltrace/compat/fcntl.h | |
6 | * | |
7 | * Copyright 2015 (c) - Jérémie Galarneau <jeremie.galarneau@efficios.com> | |
8 | * | |
9 | * fcntl compatibility layer. | |
10 | * | |
11 | * Permission is hereby granted, free of charge, to any person obtaining a copy | |
12 | * of this software and associated documentation files (the "Software"), to deal | |
13 | * in the Software without restriction, including without limitation the rights | |
14 | * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
15 | * copies of the Software, and to permit persons to whom the Software is | |
16 | * furnished to do so, subject to the following conditions: | |
17 | * | |
18 | * The above copyright notice and this permission notice shall be included in | |
19 | * all copies or substantial portions of the Software. | |
20 | * | |
21 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
22 | * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
23 | * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
24 | * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
25 | * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
26 | * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE | |
27 | * SOFTWARE. | |
28 | */ | |
29 | ||
a323afb2 JG |
30 | #ifdef BABELTRACE_HAVE_POSIX_FALLOCATE |
31 | ||
32 | #include <fcntl.h> | |
33 | ||
34 | static inline | |
35 | int bt_posix_fallocate(int fd, off_t offset, off_t len) | |
36 | { | |
37 | return posix_fallocate(fd, offset, len); | |
38 | } | |
39 | ||
40 | #else /* #ifdef BABELTRACE_HAVE_POSIX_FALLOCATE */ | |
41 | ||
42 | #include <sys/types.h> | |
43 | #include <unistd.h> | |
44 | #include <string.h> | |
45 | ||
46 | #define BABELTRACE_FALLOCATE_BUFLEN 256 | |
47 | ||
48 | #ifndef min_t | |
49 | #define min_t(type, a, b) \ | |
50 | ((type) (a) < (type) (b) ? (type) (a) : (type) (b)) | |
51 | #endif | |
52 | ||
53 | static inline | |
54 | int bt_posix_fallocate(int fd, off_t offset, off_t len) | |
55 | { | |
56 | int ret = 0; | |
57 | ssize_t copy_len; | |
58 | char buf[BABELTRACE_FALLOCATE_BUFLEN]; | |
59 | off_t i, file_pos, orig_end_offset, range_end; | |
60 | ||
61 | if (offset < 0 || len < 0) { | |
62 | ret = EINVAL; | |
63 | goto end; | |
64 | } | |
65 | ||
66 | range_end = offset + len; | |
67 | if (range_end < 0) { | |
68 | ret = EFBIG; | |
69 | goto end; | |
70 | } | |
71 | ||
72 | file_pos = lseek(fd, 0, SEEK_CUR); | |
73 | if (file_pos < 0) { | |
74 | ret = errno; | |
75 | goto end; | |
76 | } | |
77 | ||
78 | orig_end_offset = lseek(fd, 0, SEEK_END); | |
79 | if (orig_end_offset < 0) { | |
80 | ret = errno; | |
81 | goto end; | |
82 | } | |
83 | ||
84 | /* Seek back to original position. */ | |
85 | ret = lseek(fd, file_pos, SEEK_SET); | |
86 | if (ret) { | |
87 | ret = errno; | |
88 | goto end; | |
89 | } | |
90 | ||
91 | /* | |
92 | * The file may not need to grow, but we want to ensure the | |
93 | * space has actually been reserved by the file system. First, copy | |
94 | * the "existing" region of the file, then grow the file if needed. | |
95 | */ | |
96 | for (i = file_pos; i < min_t(off_t, range_end, orig_end_offset); | |
97 | i += copy_len) { | |
98 | ssize_t copy_ret; | |
99 | ||
100 | copy_len = min_t(size_t, BABELTRACE_FALLOCATE_BUFLEN, | |
101 | min_t(off_t, range_end - i, | |
102 | orig_end_offset - i)); | |
103 | copy_ret = pread(fd, &buf, copy_len, i); | |
104 | if (copy_ret < copy_len) { | |
105 | /* | |
106 | * The caller must handle any EINTR. | |
107 | * POSIX_FALLOCATE(3) does not mention EINTR. | |
108 | * However, glibc does forward to fallocate() | |
109 | * directly on Linux, which may be interrupted. | |
110 | */ | |
111 | ret = errno; | |
112 | goto end; | |
113 | } | |
114 | ||
115 | copy_ret = pwrite(fd, &buf, copy_len, i); | |
116 | if (copy_ret < copy_len) { | |
117 | /* Same caveat as noted at pread() */ | |
118 | ret = errno; | |
119 | goto end; | |
120 | } | |
121 | } | |
122 | ||
123 | /* Grow file, as necessary. */ | |
124 | memset(&buf, 0, BABELTRACE_FALLOCATE_BUFLEN); | |
125 | for (i = orig_end_offset; i < range_end; i += copy_len) { | |
126 | ssize_t write_ret; | |
127 | ||
128 | copy_len = min_t(size_t, BABELTRACE_FALLOCATE_BUFLEN, | |
129 | range_end - i); | |
130 | write_ret = pwrite(fd, &buf, copy_len, i); | |
131 | if (write_ret < copy_len) { | |
132 | ret = errno; | |
133 | goto end; | |
134 | } | |
135 | } | |
136 | end: | |
137 | return ret; | |
138 | } | |
139 | #endif /* #else #ifdef BABELTRACE_HAVE_POSIX_FALLOCATE */ | |
140 | ||
0bb657dc MD |
141 | |
142 | #ifdef BABELTRACE_HAVE_FACCESSAT | |
143 | ||
144 | #include <fcntl.h> | |
145 | #include <unistd.h> | |
146 | ||
147 | static inline | |
148 | int bt_faccessat(int dirfd, const char *dirname, | |
149 | const char *pathname, int mode, int flags) | |
150 | { | |
151 | return faccessat(dirfd, pathname, mode, flags); | |
152 | } | |
153 | ||
154 | #else /* #ifdef BABELTRACE_HAVE_FACCESSAT */ | |
155 | ||
156 | #include <string.h> | |
157 | #include <unistd.h> | |
158 | ||
159 | static inline | |
160 | int bt_faccessat(int dirfd, const char *dirname, | |
161 | const char *pathname, int mode, int flags) | |
162 | { | |
163 | char cpath[PATH_MAX]; | |
164 | ||
165 | if (flags != 0) { | |
166 | errno = EINVAL; | |
167 | return -1; | |
168 | } | |
169 | /* Includes middle / and final \0. */ | |
170 | if (strlen(dirname) + strlen(pathname) + 2 > PATH_MAX) { | |
171 | return -1; | |
172 | } | |
173 | strcpy(cpath, dirname); | |
174 | strcat(cpath, "/"); | |
175 | strcat(cpath, pathname); | |
176 | return access(cpath, mode); | |
177 | } | |
178 | ||
179 | #endif /* #else #ifdef BABELTRACE_HAVE_FACCESSAT */ | |
180 | ||
a323afb2 | 181 | #endif /* _BABELTRACE_COMPAT_FCNTL_H */ |