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990570ed DG |
1 | /* |
2 | * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca> | |
3 | * Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
4 | * | |
d14d33bf AM |
5 | * This program is free software; you can redistribute it and/or modify |
6 | * it under the terms of the GNU General Public License, version 2 only, | |
7 | * as published by the Free Software Foundation. | |
990570ed DG |
8 | * |
9 | * This program is distributed in the hope that it will be useful, but WITHOUT | |
10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
d14d33bf | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for |
990570ed DG |
12 | * more details. |
13 | * | |
d14d33bf AM |
14 | * You should have received a copy of the GNU General Public License along |
15 | * with this program; if not, write to the Free Software Foundation, Inc., | |
16 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. | |
990570ed DG |
17 | */ |
18 | ||
19 | #ifndef _MACROS_H | |
20 | #define _MACROS_H | |
21 | ||
22 | #include <stdlib.h> | |
93375aa6 | 23 | #include <stddef.h> |
f6835b82 | 24 | #include <string.h> |
639082d2 | 25 | #include <common/compat/string.h> |
990570ed DG |
26 | |
27 | /* | |
28 | * Takes a pointer x and transform it so we can use it to access members | |
29 | * without a function call. Here an example: | |
30 | * | |
31 | * #define GET_SIZE(x) LTTNG_REF(x)->size | |
32 | * | |
33 | * struct { int size; } s; | |
34 | * | |
35 | * printf("size : %d\n", GET_SIZE(&s)); | |
36 | * | |
37 | * For this example we can't use something like this for compatibility purpose | |
38 | * since this will fail: | |
39 | * | |
40 | * #define GET_SIZE(x) x->size; | |
41 | * | |
42 | * This is mostly use for the compatibility layer of lttng-tools. See | |
43 | * poll/epoll for a good example. Since x can be on the stack or allocated | |
44 | * memory using malloc(), we must use generic accessors for compat in order to | |
45 | * *not* use a function to access members and not the variable name. | |
46 | */ | |
47 | #define LTTNG_REF(x) ((typeof(*x) *)(x)) | |
48 | ||
49 | /* | |
50 | * Memory allocation zeroed | |
51 | */ | |
4616a46c MD |
52 | static inline |
53 | void *zmalloc(size_t len) | |
54 | { | |
55 | return calloc(1, len); | |
56 | } | |
990570ed DG |
57 | |
58 | #ifndef ARRAY_SIZE | |
59 | #define ARRAY_SIZE(array) (sizeof(array) / (sizeof((array)[0]))) | |
60 | #endif | |
61 | ||
93375aa6 JG |
62 | #ifndef container_of |
63 | #define container_of(ptr, type, member) \ | |
64 | ({ \ | |
65 | const typeof(((type *)NULL)->member) * __ptr = (ptr); \ | |
66 | (type *)((char *)__ptr - offsetof(type, member)); \ | |
67 | }) | |
68 | #endif | |
69 | ||
cf3f19ae SM |
70 | #ifndef max |
71 | #define max(a, b) ((a) > (b) ? (a) : (b)) | |
72 | #endif | |
73 | ||
331744e3 JD |
74 | #ifndef max_t |
75 | #define max_t(type, a, b) ((type) max(a, b)) | |
76 | #endif | |
77 | ||
cf3f19ae SM |
78 | #ifndef min |
79 | #define min(a, b) ((a) < (b) ? (a) : (b)) | |
80 | #endif | |
81 | ||
54c90d10 DG |
82 | #ifndef LTTNG_PACKED |
83 | #define LTTNG_PACKED __attribute__((__packed__)) | |
84 | #endif | |
85 | ||
70c6956b MJ |
86 | /* |
87 | * LTTNG_HIDDEN: set the hidden attribute for internal functions | |
88 | * On Windows, symbols are local unless explicitly exported, | |
89 | * see https://gcc.gnu.org/wiki/Visibility | |
90 | */ | |
91 | #if defined(_WIN32) || defined(__CYGWIN__) | |
92 | #define LTTNG_HIDDEN | |
93 | #else | |
99c815c1 DG |
94 | #define LTTNG_HIDDEN __attribute__((visibility("hidden"))) |
95 | #endif | |
96 | ||
f8f3885c MD |
97 | #define member_sizeof(type, field) sizeof(((type *) 0)->field) |
98 | ||
f6835b82 MD |
99 | /* |
100 | * lttng_strncpy returns 0 on success, or nonzero on failure. | |
101 | * It checks that the @src string fits into @dst_len before performing | |
102 | * the copy. On failure, no copy has been performed. | |
103 | * | |
104 | * dst_len includes the string's trailing NULL. | |
105 | */ | |
106 | static inline | |
107 | int lttng_strncpy(char *dst, const char *src, size_t dst_len) | |
108 | { | |
639082d2 | 109 | if (lttng_strnlen(src, dst_len) == dst_len) { |
f6835b82 MD |
110 | /* Fail since copying would result in truncation. */ |
111 | return -1; | |
112 | } | |
113 | strncpy(dst, src, dst_len); | |
114 | /* | |
115 | * Be extra careful and put final \0 at the end after strncpy(), | |
116 | * even though we checked the length before. This makes Coverity | |
117 | * happy. | |
118 | */ | |
119 | dst[dst_len - 1] = '\0'; | |
120 | return 0; | |
121 | } | |
122 | ||
990570ed | 123 | #endif /* _MACROS_H */ |