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1 : /* SPDX-License-Identifier: GPL-2.0-only */
2 : /*
3 : * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
4 : */
5 :
6 : #pragma once
7 :
8 : #include <assert.h>
9 : #include <errno.h>
10 : #include <stdbool.h>
11 : #include <stddef.h>
12 : #include <stdlib.h>
13 : #include <string.h>
14 : #include <unistd.h>
15 :
16 : extern const char *strerrordesc_np(int errnum);
17 :
18 : #define bf_packed __attribute__((packed))
19 : #define bf_aligned(x) __attribute__((aligned(x)))
20 : #define bf_unused __attribute__((unused))
21 :
22 : #ifndef bf_assert
23 : #define bf_assert(x) assert(x)
24 : #endif
25 :
26 : #define BF_STR(s) _BF_STR(s)
27 : #define _BF_STR(s) #s
28 :
29 : /**
30 : * Mark a variable as unused, to prevent the compiler from emitting a warning.
31 : *
32 : * @param x The variable to mark as unused.
33 : */
34 : #define UNUSED(x) (void)(x)
35 :
36 : /**
37 : * Set @p ptr to NULL and return its previous value.
38 : *
39 : * Inspired from systemd's TAKE_PTR() macro, which is itself inspired from
40 : * Rust's Option::take() method:
41 : * https://doc.rust-lang.org/std/option/enum.Option.html#method.take
42 : *
43 : * @param var Variable to return the value of.
44 : * @param type Type of @p var.
45 : * @param nullvalue Value to set @p var to.
46 : * @return Value of @p var before it was set to @p nullvalue.
47 : */
48 : #define TAKE_GENERIC(var, type, nullvalue) \
49 : ({ \
50 : /* NOLINTBEGIN: do not enclose 'type' in parentheses */ \
51 : type *_pvar_ = &(var); \
52 : type _var_ = *_pvar_; \
53 : type _nullvalue_ = nullvalue; \
54 : /* NOLINTEND */ \
55 : *_pvar_ = _nullvalue_; \
56 : _var_; \
57 : })
58 :
59 : #define TAKE_PTR_TYPE(ptr, type) TAKE_GENERIC(ptr, type, NULL)
60 : #define TAKE_PTR(ptr) TAKE_PTR_TYPE(ptr, typeof(ptr))
61 : #define TAKE_STRUCT_TYPE(s, type) TAKE_GENERIC(s, type, {})
62 : #define TAKE_STRUCT(s) TAKE_STRUCT_TYPE(s, typeof(s))
63 : #define TAKE_FD(fd) TAKE_GENERIC(fd, int, -1)
64 :
65 : /**
66 : * Get the number of element in an array.
67 : *
68 : * @param x The array.
69 : * @return size_t The number of elements in the array.
70 : */
71 : #define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
72 :
73 : #define _cleanup_free_ __attribute__((__cleanup__(freep)))
74 : #define _cleanup_close_ __attribute__((__cleanup__(closep)))
75 :
76 : /**
77 : * Return a string describing the given error code.
78 : *
79 : * This function must be used over strerror(), which is marked at mt-unsafe.
80 : *
81 : * @param v Error code, can be positive or negative.
82 : */
83 : #define bf_strerror(v) strerrordesc_np(abs(v))
84 :
85 : /**
86 : * Swap two values.
87 : *
88 : * @param a First value to swap.
89 : * @param b Second value to swap.
90 : */
91 : #define bf_swap(a, b) \
92 : do { \
93 : typeof(a) __a = (a); \
94 : (a) = (b); \
95 : (b) = __a; \
96 : } while (0)
97 :
98 : /**
99 : * Free a pointer and set it to NULL.
100 : *
101 : * @param ptr Pointer to free.
102 : */
103 0 : static inline void freep(void *ptr)
104 : {
105 121 : free(*(void **)ptr);
106 44 : *(void **)ptr = NULL;
107 18 : }
108 :
109 : /**
110 : * Close a file descriptor and set it to -1.
111 : *
112 : * File descriptors are expected to be uninitialized to -1, so this function
113 : * can be used to close a file descriptor and set it to -1 in a single
114 : * operation. If the file descriptor is already -1, it is not closed.
115 : *
116 : * @param fd File descriptor to close.
117 : */
118 : static inline void closep(int *fd)
119 : {
120 27 : if (*fd >= 0)
121 6 : close(*fd);
122 20 : *fd = -1;
123 : }
124 :
125 : /**
126 : * Duplicate a memory region.
127 : *
128 : * Allocate a new buffer of size @p len and copy @p src into it. Requirements
129 : * applicable to @p src and @p len:
130 : * - If @p src is NULL, @p len must be 0. In this case, NULL is returned.
131 : * - If @p src is non-NULL, a new buffer of @p len bytes will be allocated to
132 : * store the first @p len bytes of @p src. This new buffer is then returned.
133 : *
134 : * Unless NULL is returned, the new buffer is owned by the caller.
135 : *
136 : * @param src Source buffer to copy to @p dst.
137 : * @param len Number of bytes to copy to @p dst.
138 : * @return Pointer to the new buffer, or NULL on failure.
139 : */
140 0 : static inline void *bf_memdup(const void *src, size_t len)
141 : {
142 : void *dst;
143 :
144 0 : if (!src)
145 : return NULL;
146 :
147 0 : dst = malloc(len);
148 0 : if (!dst)
149 : return NULL;
150 :
151 0 : return memcpy(dst, src, len);
152 : }
153 :
154 : /**
155 : * Copy @p len bytes from @p src to @p dst.
156 : *
157 : * Allow for @p src to be NULL and/or @p len to be zero:
158 : * - If @p src is NULL, @p len must be equal 0. @p dst is not modified.
159 : * - If @p src is not NULL, @p len can be equal to 0, in which case @p dst is
160 : * not modified.
161 : *
162 : * @param dst Destination buffer. Can't be NULL, and must be big enough to store
163 : * @p len bytes from @p src.
164 : * @param src Source buffer to copy to @p dst.
165 : * @param len Number of bytes to copy to @p dst.
166 : * @return Pointer to @p dst.
167 : */
168 172 : static inline void *bf_memcpy(void *dst, const void *src, size_t len)
169 : {
170 172 : bf_assert(dst);
171 172 : bf_assert(src ? 1 : len == 0);
172 :
173 172 : if (!src || !len)
174 : return dst;
175 :
176 125 : return memcpy(dst, src, len);
177 : }
178 :
179 : /**
180 : * Reallocate @p ptr into a new buffer of size @p size.
181 : *
182 : * Behaves similarly to realloc(), except that @p ptr is left unchanged if
183 : * allocation fails, and an error is returned.
184 : *
185 : * @param ptr Memory buffer to grow. Can't be NULL.
186 : * @param size New size of the memory buffer.
187 : * @return 0 on success, or a negative errno value on failure.
188 : */
189 4 : static inline int bf_realloc(void **ptr, size_t size)
190 : {
191 : _cleanup_free_ void *_ptr;
192 :
193 4 : bf_assert(ptr);
194 :
195 4 : _ptr = realloc(*ptr, size);
196 4 : if (!_ptr)
197 : return -ENOMEM;
198 :
199 4 : *ptr = TAKE_PTR(_ptr);
200 :
201 4 : return 0;
202 : }
203 :
204 : /**
205 : * Returns true if @p a is equal to @p b.
206 : *
207 : * @param lhs First string.
208 : * @param rhs Second string.
209 : * @return True if @p a == @p b, false otherwise.
210 : */
211 : static inline bool bf_streq(const char *lhs, const char *rhs) // NOLINT
212 : {
213 303 : return strcmp(lhs, rhs) == 0;
214 : }
215 :
216 : /**
217 : * Read the contents of a file into a buffer.
218 : *
219 : * @param path Path to the file to read. Can't be NULL.
220 : * @param buf Pointer to a pointer to a buffer. The buffer will be allocated
221 : * automatically. The caller is responsible to free it. If @ref bf_read_file
222 : * fails, @p buf is left unchanged.
223 : * @param len Length of the allocated buffer. Populated by the function.
224 : * @return 0 on success, negative errno value on error.
225 : */
226 : int bf_read_file(const char *path, void **buf, size_t *len);
227 :
228 : /**
229 : * Write the contents of a buffer into a file.
230 : *
231 : * @param path Path to the file to write. Can't be NULL.
232 : * @param buf Buffer to write.
233 : * @param len Number of bytes to write the to file.
234 : * @return 0 on success, negative errno value on error.
235 : */
236 : int bf_write_file(const char *path, const void *buf, size_t len);
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