1 /* SPDX-License-Identifier: GPL-2.0+ */
2 /*
3 * Handles a buffer that can be allocated and freed
4 *
5 * Copyright 2021 Google LLC
6 * Written by Simon Glass <sjg@chromium.org>
7 */
8
9 #ifndef __ABUF_H
10 #define __ABUF_H
11
12 #ifdef USE_HOSTCC
13 #include <sys/types.h>
14 #else
15 #include <linux/types.h>
16 #endif
17
18 /**
19 * struct abuf - buffer that can be allocated and freed
20 *
21 * This is useful for a block of data which may be allocated with malloc(), or
22 * not, so that it needs to be freed correctly when finished with.
23 *
24 * For now it has a very simple purpose.
25 *
26 * Using memset() to zero all fields is guaranteed to be equivalent to
27 * abuf_init().
28 *
29 * @data: Pointer to data
30 * @size: Size of data in bytes
31 * @alloced: true if allocated with malloc(), so must be freed after use
32 */
33 struct abuf {
34 void *data;
35 size_t size;
36 bool alloced;
37 };
38
abuf_data(const struct abuf * abuf)39 static inline void *abuf_data(const struct abuf *abuf)
40 {
41 return abuf->data;
42 }
43
abuf_size(const struct abuf * abuf)44 static inline size_t abuf_size(const struct abuf *abuf)
45 {
46 return abuf->size;
47 }
48
49 /**
50 * abuf_addr() - Get the address of a buffer's data
51 *
52 * @abuf: Buffer to check
53 * Return: address of buffer
54 */
55 ulong abuf_addr(const struct abuf *abuf);
56
57 /**
58 * abuf_set() - set the (unallocated) data in a buffer
59 *
60 * This simply makes the abuf point to the supplied data, which must be live
61 * for the lifetime of the abuf. It is not alloced.
62 *
63 * Any existing data in the abuf is freed and the alloced member is set to
64 * false.
65 *
66 * @abuf: abuf to adjust
67 * @data: New contents of abuf
68 * @size: New size of abuf
69 */
70 void abuf_set(struct abuf *abuf, void *data, size_t size);
71
72 /**
73 * abuf_map_sysmem() - calls map_sysmem() to set up an abuf
74 *
75 * This is equivalent to abuf_set(abuf, map_sysmem(addr, size), size)
76 *
77 * Any existing data in the abuf is freed and the alloced member is set to
78 * false.
79 *
80 * @abuf: abuf to adjust
81 * @addr: Address to set the abuf to
82 * @size: New size of abuf
83 */
84 void abuf_map_sysmem(struct abuf *abuf, ulong addr, size_t size);
85
86 /**
87 * abuf_realloc() - Change the size of a buffer
88 *
89 * This uses realloc() to change the size of the buffer, with the same semantics
90 * as that function. If the abuf is not currently alloced, then it will alloc
91 * it if the size needs to increase (i.e. set the alloced member to true)
92 *
93 * @abuf: abuf to adjust
94 * @new_size: new size in bytes.
95 * if 0, the abuf is freed
96 * if greater than the current size, the abuf is extended and the new
97 * space is not inited. The alloced member is set to true
98 * if less than the current size, the abuf is contracted and the data at
99 * the end is lost. If @new_size is 0, this sets the alloced member to
100 * false
101 * Return: true if OK, false if out of memory
102 */
103 bool abuf_realloc(struct abuf *abuf, size_t new_size);
104
105 /**
106 * abuf_realloc_inc() - Increment abuf size by a given amount
107 *
108 * @abuf: abuf to adjust
109 * @inc: Size incrmement to use (the buffer size will be increased by this much)
110 * Return: true if OK, false if out of memory
111 */
112 bool abuf_realloc_inc(struct abuf *abuf, size_t inc);
113
114 /**
115 * abuf_copy() - Make a copy of an abuf
116 *
117 * Creates an allocated copy of @old in @new
118 *
119 * @old: abuf to copy
120 * @new: new abuf to hold the copy (inited by this function)
121 * Return: true if OK, false if out of memory
122 */
123 bool abuf_copy(const struct abuf *old, struct abuf *new);
124
125 /**
126 * abuf_printf() - Format a string and place it in an abuf
127 *
128 * @buf: The buffer to place the result into
129 * @fmt: The format string to use
130 * @...: Arguments for the format string
131 * Return: the number of characters writtenwhich would be
132 * generated for the given input, excluding the trailing null,
133 * as per ISO C99.
134 *
135 * The abuf is expanded as necessary to fit the formated string
136 *
137 * See the vsprintf() documentation for format string extensions over C99.
138 *
139 * Returns: number of characters written (excluding trailing nul) on success,
140 * -E2BIG if the size exceeds 4K, -ENOMEM if out of memory, -EFAULT if there is
141 * an internal bug in the vsnprintf() implementation
142 */
143 int abuf_printf(struct abuf *buf, const char *fmt, ...)
144 __attribute__ ((format (__printf__, 2, 3)));
145
146 /**
147 * abuf_uninit_move() - Return the allocated contents and uninit the abuf
148 *
149 * This returns the abuf data to the caller, allocating it if necessary, so that
150 * the caller receives data that it can be sure will hang around. The caller is
151 * responsible for freeing the data.
152 *
153 * If the abuf has allocated data, it is returned. If the abuf has data but it
154 * is not allocated, then it is first allocated, then returned.
155 *
156 * If the abuf size is 0, this returns NULL
157 *
158 * The abuf is uninited as part of this, except if the allocation fails, in
159 * which NULL is returned and the abuf remains untouched.
160 *
161 * The abuf must be inited before this can be called.
162 *
163 * @abuf: abuf to uninit
164 * @sizep: if non-NULL, returns the size of the returned data
165 * Return: data contents, allocated with malloc(), or NULL if the data could not
166 * be allocated, or the data size is 0
167 */
168 void *abuf_uninit_move(struct abuf *abuf, size_t *sizep);
169
170 /**
171 * abuf_init_move() - Make abuf take over the management of an allocated region
172 *
173 * After this, @data must not be used. All access must be via the abuf.
174 *
175 * @abuf: abuf to init
176 * @data: Existing allocated buffer to place in the abuf
177 * @size: Size of allocated buffer
178 */
179 void abuf_init_move(struct abuf *abuf, void *data, size_t size);
180
181 /**
182 * abuf_init_set() - Set up a new abuf
183 *
184 * Inits a new abuf and sets up its (unallocated) data
185 *
186 * @abuf: abuf to set up
187 * @data: New contents of abuf
188 * @size: New size of abuf
189 */
190 void abuf_init_set(struct abuf *abuf, void *data, size_t size);
191
192 /**
193 * abuf_init_const() - Set up a new const abuf
194 *
195 * Inits a new abuf and sets up its (unallocated) data. The only current
196 * difference between this and abuf_init_set() is the 'data' parameter is a
197 * const pointer. At some point a flag could be used to indicate const-ness.
198 *
199 * @abuf: abuf to set up
200 * @data: New contents of abuf
201 * @size: New size of abuf
202 */
203 void abuf_init_const(struct abuf *abuf, const void *data, size_t size);
204
205 /**
206 * abuf_init_size() - Set up an allocated abuf
207 *
208 * Init a new abuf and allocate its size.
209 *
210 * @abuf: abuf to set up
211 * @data: New contents of abuf
212 * @size: New size of abuf
213 */
214 bool abuf_init_size(struct abuf *buf, size_t size);
215
216 /**
217 * abuf_uninit() - Free any memory used by an abuf
218 *
219 * The buffer must be inited before this can be called.
220 *
221 * @abuf: abuf to uninit
222 */
223 void abuf_uninit(struct abuf *abuf);
224
225 /**
226 * abuf_init() - Set up a new abuf
227 *
228 * This initially has no data and alloced is set to false. This is equivalent to
229 * setting all fields to 0, e.g. with memset(), so callers can do that instead
230 * if desired.
231 *
232 * @abuf: abuf to set up
233 */
234 void abuf_init(struct abuf *abuf);
235
236 #endif
237